Updated pod version to 0.21

Removed unnecessary properties from SessionDelegate
Added progressive downloading for HTTP-based providers
2017-10-27 09:21:17 +03:30 · 2017-10-26 14:07:57 +03:30 · 2017-10-26 13:56:41 +03:30 · 2017-10-13 08:55:55 +03:30 · 2017-10-13 02:31:31 +03:30 · 2017-10-12 18:30:28 +03:30
35 changed files with 6643 additions and 3291 deletions
@@ -12,8 +12,8 @@ env:
  - MACOS_SDK=macosx
  - TVOS_SDK=appletvsimulator
  matrix:
-    - DESTINATION="OS=10.2,name=iPad Air 2"        SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="YES" CARTHAGEDEPLOY="NO"
-    - DESTINATION="OS=9.0,name=iPhone 6"           SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="YES"
+    - DESTINATION="OS=10.2,name=iPad Air 2"        SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO" CARTHAGEDEPLOY="YES"
+    - DESTINATION="OS=9.0,name=iPhone 6"           SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="YES"  CARTHAGEDEPLOY="NO"
    - DESTINATION="OS=8.1,name=iPhone 4S"          SCHEME="$IOS_FRAMEWORK_SCHEME"     SDK="$IOS_SDK"     RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="NO"

    - DESTINATION="OS=10.1,name=Apple TV 1080p"    SCHEME="$TVOS_FRAMEWORK_SCHEME"    SDK="$TVOS_SDK"    RUN_TESTS="NO" BUILD_EXAMPLE="NO" POD="NO"  CARTHAGEDEPLOY="NO"
@@ -56,7 +56,7 @@ script:
 after_success:
  # Run `pod trunk push` if specified
  - if [ $POD == "YES" ] && [ -n "$TRAVIS_TAG" ]; then
-      pod trunk push;
+      pod trunk push --allow-warnings;
    fi

 #   - bash <(curl -s https://codecov.io/bash)
@@ -75,6 +75,7 @@ deploy:
  file: $FRAMEWORK_NAME.zip
  skip_cleanup: true
  on:
-    repo: amosavian/$PROJECTNAME
+    # repo: amosavian/$PROJECTNAME
+    repo: amosavian/FileProvider
    tags: true
    condition: "$CARTHAGEDEPLOY = YES"
@@ -1,5 +1,5 @@
 #
-#  Be sure to run `pod spec lint FileProvider.podspec' to ensure this is a
+#  Be sure to run `pod spec lint FilesProvider.podspec' to ensure this is a
 #  valid spec and to remove all comments including this before submitting the spec.
 #
 #  To learn more about Podspec attributes see http://docs.cocoapods.org/specification.html
@@ -15,9 +15,9 @@ Pod::Spec.new do |s|
  #  summary should be tweet-length, and the description more in depth.
  #

-  s.name         = "FileProvider"
-  s.version      = "0.14.4"
-  s.summary      = "FileManager replacement for Local and Remote (WebDAV/Dropbox/OneDrive/SMB2) files on iOS and macOS."
+  s.name         = "FilesProvider"
+  s.version      = "0.21.0"
+  s.summary      = "FileManager replacement for Local and Remote (WebDAV/FTP/Dropbox/OneDrive/SMB2) files on iOS and macOS."

  # This description is used to generate tags and improve search results.
  #   * Think: What does it do? Why did you write it? What is the focus?
@@ -58,7 +58,7 @@ Pod::Spec.new do |s|
  s.author             = { "Amir Abbas Mousavian" => "a.mosavian@gmail.com" }
  # Or just: s.author    = "Amir Abbas Mousavian"
  # s.authors            = { "Amir Abbas Mousavian" => "a.mosavian@gmail.com" }
-  # s.social_media_url   = "https://twitter.com/amosavian"
+  s.social_media_url   = "https://twitter.com/amosavian"

  # ――― Platform Specifics ――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
  #
@@ -35,6 +35,15 @@
 		792572411DF23BDA006A1526 /* LocalHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 792572401DF23BDA006A1526 /* LocalHelper.swift */; };
 		792572421DF23BDA006A1526 /* LocalHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 792572401DF23BDA006A1526 /* LocalHelper.swift */; };
 		792572431DF23BDA006A1526 /* LocalHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 792572401DF23BDA006A1526 /* LocalHelper.swift */; };
+		7936BC121E880F5700A6C81C /* FTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7936BC111E880F5700A6C81C /* FTPFileProvider.swift */; };
+		7936BC131E880F5700A6C81C /* FTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7936BC111E880F5700A6C81C /* FTPFileProvider.swift */; };
+		7936BC141E880F5700A6C81C /* FTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7936BC111E880F5700A6C81C /* FTPFileProvider.swift */; };
+		793CCE2A1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */; };
+		793CCE2B1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */; };
+		793CCE2C1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */; };
+		793CCE2E1F4B8C7B00BC8288 /* HashMAC.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */; };
+		793CCE2F1F4B8C7B00BC8288 /* HashMAC.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */; };
+		793CCE301F4B8C7B00BC8288 /* HashMAC.swift in Sources */ = {isa = PBXBuildFile; fileRef = 793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */; };
 		79480FF61E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */; };
 		79480FF71E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */; };
 		79480FF81E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */; };
@@ -47,9 +56,10 @@
 		794C220E1D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
 		794C220F1D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
 		794C22101D591A4B00EC49B8 /* SMB2QueryTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = 794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */; };
-		796807551E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
-		796807561E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
-		796807571E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */; };
+		7958155A1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		7958155B1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		7958155C1F478ED9003344DD /* HTTPFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 795815591F478ED9003344DD /* HTTPFileProvider.swift */; };
+		798654331E8874BC002FA550 /* FTPHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 798654321E8874BC002FA550 /* FTPHelper.swift */; };
 		799396AA1D48C02300086753 /* DropboxFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396931D48C02300086753 /* DropboxFileProvider.swift */; };
 		799396AB1D48C02300086753 /* DropboxFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396931D48C02300086753 /* DropboxFileProvider.swift */; };
 		799396AC1D48C02300086753 /* DropboxFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799396931D48C02300086753 /* DropboxFileProvider.swift */; };
@@ -112,12 +122,14 @@
 		79BD63BE1E2CC3C20035128C /* ImageIO.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 79BD63BD1E2CC3C20035128C /* ImageIO.framework */; };
 		79BD63C01E2CC3CD0035128C /* CoreGraphics.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 79BD63BF1E2CC3CD0035128C /* CoreGraphics.framework */; };
 		79BD63C21E2CC3D30035128C /* AVFoundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 79BD63C11E2CC3D30035128C /* AVFoundation.framework */; };
-		79BD63C51E2D17880035128C /* OneDriveFileProvide.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */; };
-		79BD63C61E2D17880035128C /* OneDriveFileProvide.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */; };
-		79BD63C71E2D17880035128C /* OneDriveFileProvide.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */; };
+		79BD63C51E2D17880035128C /* OneDriveFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */; };
+		79BD63C61E2D17880035128C /* OneDriveFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */; };
+		79BD63C71E2D17880035128C /* OneDriveFileProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */; };
 		79BD63C81E2D17880035128C /* OneDriveHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C41E2D17880035128C /* OneDriveHelper.swift */; };
 		79BD63C91E2D17880035128C /* OneDriveHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C41E2D17880035128C /* OneDriveHelper.swift */; };
 		79BD63CA1E2D17880035128C /* OneDriveHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79BD63C41E2D17880035128C /* OneDriveHelper.swift */; };
+		79F4678B1E8B80F200C91A85 /* FTPHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 798654321E8874BC002FA550 /* FTPHelper.swift */; };
+		79F4678C1E8B80F200C91A85 /* FTPHelper.swift in Sources */ = {isa = PBXBuildFile; fileRef = 798654321E8874BC002FA550 /* FTPHelper.swift */; };
 		79F5745B1DFDB10B00179ABF /* FileObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79F5745A1DFDB10A00179ABF /* FileObject.swift */; };
 		79F5745C1DFDB10B00179ABF /* FileObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79F5745A1DFDB10A00179ABF /* FileObject.swift */; };
 		79F5745D1DFDB10B00179ABF /* FileObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 79F5745A1DFDB10A00179ABF /* FileObject.swift */; };
@@ -133,14 +145,18 @@
 		7924B1921D89DAE000589DB7 /* Parser.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Parser.swift; sourceTree = "<group>"; };
 		7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FPSStreamTask.swift; sourceTree = "<group>"; };
 		792572401DF23BDA006A1526 /* LocalHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LocalHelper.swift; sourceTree = "<group>"; };
+		7936BC111E880F5700A6C81C /* FTPFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FTPFileProvider.swift; sourceTree = "<group>"; };
+		793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FoundationExtensions.swift; sourceTree = "<group>"; };
+		793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HashMAC.swift; sourceTree = "<group>"; };
 		79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CloudFileProvider.swift; sourceTree = "<group>"; };
 		794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DropboxHelper.swift; sourceTree = "<group>"; };
 		794C22091D5893F800EC49B8 /* SMB2Notification.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SMB2Notification.swift; sourceTree = "<group>"; };
 		794C220D1D591A4B00EC49B8 /* SMB2QueryTypes.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SMB2QueryTypes.swift; sourceTree = "<group>"; };
-		796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileProviderExtensions.swift; sourceTree = "<group>"; };
-		799396671D48B7F600086753 /* FileProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FileProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		799396751D48B80D00086753 /* FileProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FileProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		799396821D48B82700086753 /* FileProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FileProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		795815591F478ED9003344DD /* HTTPFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HTTPFileProvider.swift; sourceTree = "<group>"; };
+		798654321E8874BC002FA550 /* FTPHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FTPHelper.swift; sourceTree = "<group>"; };
+		799396671D48B7F600086753 /* FilesProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FilesProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		799396751D48B80D00086753 /* FilesProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FilesProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		799396821D48B82700086753 /* FilesProvider.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = FilesProvider.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		7993968B1D48B8C700086753 /* Info-iOS.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-iOS.plist"; sourceTree = "<group>"; };
 		7993968C1D48B8C700086753 /* Info-MacOS.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-MacOS.plist"; sourceTree = "<group>"; };
 		7993968D1D48B8C700086753 /* Info-tvOS.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = "Info-tvOS.plist"; sourceTree = "<group>"; };
@@ -174,7 +190,7 @@
 		79BD63BD1E2CC3C20035128C /* ImageIO.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = ImageIO.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS10.1.sdk/System/Library/Frameworks/ImageIO.framework; sourceTree = DEVELOPER_DIR; };
 		79BD63BF1E2CC3CD0035128C /* CoreGraphics.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreGraphics.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS10.1.sdk/System/Library/Frameworks/CoreGraphics.framework; sourceTree = DEVELOPER_DIR; };
 		79BD63C11E2CC3D30035128C /* AVFoundation.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AVFoundation.framework; path = Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS10.1.sdk/System/Library/Frameworks/AVFoundation.framework; sourceTree = DEVELOPER_DIR; };
-		79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OneDriveFileProvide.swift; sourceTree = "<group>"; };
+		79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OneDriveFileProvider.swift; sourceTree = "<group>"; };
 		79BD63C41E2D17880035128C /* OneDriveHelper.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OneDriveHelper.swift; sourceTree = "<group>"; };
 		79F5745A1DFDB10A00179ABF /* FileObject.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = FileObject.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -247,6 +263,15 @@
 			path = AEXML;
 			sourceTree = "<group>";
 		};
+		793CCE281F4B8C3600BC8288 /* Extensions */ = {
+			isa = PBXGroup;
+			children = (
+				793CCE291F4B8C5C00BC8288 /* FoundationExtensions.swift */,
+				793CCE2D1F4B8C7B00BC8288 /* HashMAC.swift */,
+			);
+			path = Extensions;
+			sourceTree = "<group>";
+		};
 		7993965B1D48B7BF00086753 = {
 			isa = PBXGroup;
 			children = (
@@ -261,9 +286,9 @@
 		799396681D48B7F600086753 /* Products */ = {
 			isa = PBXGroup;
 			children = (
-				799396671D48B7F600086753 /* FileProvider.framework */,
-				799396751D48B80D00086753 /* FileProvider.framework */,
-				799396821D48B82700086753 /* FileProvider.framework */,
+				799396671D48B7F600086753 /* FilesProvider.framework */,
+				799396751D48B80D00086753 /* FilesProvider.framework */,
+				799396821D48B82700086753 /* FilesProvider.framework */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -282,24 +307,27 @@
 			isa = PBXGroup;
 			children = (
 				7924B18B1D89DAE000589DB7 /* AEXML */,
+				793CCE281F4B8C3600BC8288 /* Extensions */,
 				799396991D48C02300086753 /* SMBTypes */,
 				799396941D48C02300086753 /* FileProvider.h */,
 				799396951D48C02300086753 /* FileProvider.swift */,
-				796807541E7BF17E00BBB87B /* FileProviderExtensions.swift */,
 				79F5745A1DFDB10A00179ABF /* FileObject.swift */,
 				799396961D48C02300086753 /* LocalFileProvider.swift */,
 				792572401DF23BDA006A1526 /* LocalHelper.swift */,
 				79480FF51E3ABDD0007E7275 /* CloudFileProvider.swift */,
 				79BD638B1E2CC2300035128C /* ExtendedLocalFileProvider.swift */,
+				7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */,
 				7902C0851D61B56D00564440 /* RemoteSession.swift */,
+				795815591F478ED9003344DD /* HTTPFileProvider.swift */,
 				799396931D48C02300086753 /* DropboxFileProvider.swift */,
 				794C21FD1D58912A00EC49B8 /* DropboxHelper.swift */,
-				79BD63C31E2D17880035128C /* OneDriveFileProvide.swift */,
+				79BD63C31E2D17880035128C /* OneDriveFileProvider.swift */,
 				79BD63C41E2D17880035128C /* OneDriveHelper.swift */,
-				7924B1A81D89F79200589DB7 /* FPSStreamTask.swift */,
+				799396A61D48C02300086753 /* WebDAVFileProvider.swift */,
+				7936BC111E880F5700A6C81C /* FTPFileProvider.swift */,
+				798654321E8874BC002FA550 /* FTPHelper.swift */,
 				799396971D48C02300086753 /* SMBClient.swift */,
 				799396981D48C02300086753 /* SMBFileProvider.swift */,
-				799396A61D48C02300086753 /* WebDAVFileProvider.swift */,
 			);
 			path = Sources;
 			sourceTree = "<group>";
@@ -358,9 +386,9 @@
 /* End PBXHeadersBuildPhase section */

 /* Begin PBXNativeTarget section */
-		799396661D48B7F600086753 /* FileProvider iOS */ = {
+		799396661D48B7F600086753 /* FilesProvider iOS */ = {
 			isa = PBXNativeTarget;
-			buildConfigurationList = 7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FileProvider iOS" */;
+			buildConfigurationList = 7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FilesProvider iOS" */;
 			buildPhases = (
 				799396621D48B7F600086753 /* Sources */,
 				799396631D48B7F600086753 /* Frameworks */,
@@ -371,14 +399,14 @@
 			);
 			dependencies = (
 			);
-			name = "FileProvider iOS";
+			name = "FilesProvider iOS";
 			productName = "FileProvider iOS";
-			productReference = 799396671D48B7F600086753 /* FileProvider.framework */;
+			productReference = 799396671D48B7F600086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
-		799396741D48B80D00086753 /* FileProvider OSX */ = {
+		799396741D48B80D00086753 /* FilesProvider OSX */ = {
 			isa = PBXNativeTarget;
-			buildConfigurationList = 7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FileProvider OSX" */;
+			buildConfigurationList = 7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FilesProvider OSX" */;
 			buildPhases = (
 				799396701D48B80D00086753 /* Sources */,
 				799396711D48B80D00086753 /* Frameworks */,
@@ -389,14 +417,14 @@
 			);
 			dependencies = (
 			);
-			name = "FileProvider OSX";
+			name = "FilesProvider OSX";
 			productName = "FileProvider OSX";
-			productReference = 799396751D48B80D00086753 /* FileProvider.framework */;
+			productReference = 799396751D48B80D00086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
-		799396811D48B82700086753 /* FileProvider tvOS */ = {
+		799396811D48B82700086753 /* FilesProvider tvOS */ = {
 			isa = PBXNativeTarget;
-			buildConfigurationList = 799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FileProvider tvOS" */;
+			buildConfigurationList = 799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FilesProvider tvOS" */;
 			buildPhases = (
 				7993967D1D48B82700086753 /* Sources */,
 				7993967E1D48B82700086753 /* Frameworks */,
@@ -407,9 +435,9 @@
 			);
 			dependencies = (
 			);
-			name = "FileProvider tvOS";
+			name = "FilesProvider tvOS";
 			productName = "FileProvider tvOS";
-			productReference = 799396821D48B82700086753 /* FileProvider.framework */;
+			productReference = 799396821D48B82700086753 /* FilesProvider.framework */;
 			productType = "com.apple.product-type.framework";
 		};
 /* End PBXNativeTarget section */
@@ -432,7 +460,7 @@
 					};
 				};
 			};
-			buildConfigurationList = 7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FileProvider" */;
+			buildConfigurationList = 7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FilesProvider" */;
 			compatibilityVersion = "Xcode 3.2";
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
@@ -444,9 +472,9 @@
 			projectDirPath = "";
 			projectRoot = "";
 			targets = (
-				799396661D48B7F600086753 /* FileProvider iOS */,
-				799396741D48B80D00086753 /* FileProvider OSX */,
-				799396811D48B82700086753 /* FileProvider tvOS */,
+				799396661D48B7F600086753 /* FilesProvider iOS */,
+				799396741D48B80D00086753 /* FilesProvider OSX */,
+				799396811D48B82700086753 /* FilesProvider tvOS */,
 			);
 		};
 /* End PBXProject section */
@@ -480,17 +508,19 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				796807551E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B31D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D41D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A21D89DAE000589DB7 /* Options.swift in Sources */,
 				792572411DF23BDA006A1526 /* LocalHelper.swift in Sources */,
+				7936BC121E880F5700A6C81C /* FTPFileProvider.swift in Sources */,
 				79480FF61E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */,
 				79F5745B1DFDB10B00179ABF /* FileObject.swift in Sources */,
-				79BD63C51E2D17880035128C /* OneDriveFileProvide.swift in Sources */,
+				79BD63C51E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1991D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C81D48C02300086753 /* SMB2IOCtl.swift in Sources */,
 				799396D71D48C02300086753 /* SMB2Types.swift in Sources */,
+				7958155A1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
+				798654331E8874BC002FA550 /* FTPHelper.swift in Sources */,
 				7924B1B21D89FCDA00589DB7 /* FPSStreamTask.swift in Sources */,
 				799396C51D48C02300086753 /* SMB2FileOperation.swift in Sources */,
 				79BD63C81E2D17880035128C /* OneDriveHelper.swift in Sources */,
@@ -507,10 +537,12 @@
 				799396E01D48C02300086753 /* WebDAVFileProvider.swift in Sources */,
 				799396DA1D48C02300086753 /* SMBErrorType.swift in Sources */,
 				799396C21D48C02300086753 /* SMB2FileHandle.swift in Sources */,
+				793CCE2E1F4B8C7B00BC8288 /* HashMAC.swift in Sources */,
 				799396CB1D48C02300086753 /* SMB2Query.swift in Sources */,
 				799396AA1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
 				79BD638C1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				7924B1B31D89FD6400589DB7 /* SMBClient.swift in Sources */,
+				793CCE2A1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */,
 				7924B1A51D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B01D48C02300086753 /* FileProvider.swift in Sources */,
 				7924B19C1D89DAE000589DB7 /* Error.swift in Sources */,
@@ -521,17 +553,19 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				796807561E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B41D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D51D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A31D89DAE000589DB7 /* Options.swift in Sources */,
 				792572421DF23BDA006A1526 /* LocalHelper.swift in Sources */,
+				7936BC131E880F5700A6C81C /* FTPFileProvider.swift in Sources */,
 				79480FF71E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */,
 				79F5745C1DFDB10B00179ABF /* FileObject.swift in Sources */,
-				79BD63C61E2D17880035128C /* OneDriveFileProvide.swift in Sources */,
+				79BD63C61E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1B01D89F7DE00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19A1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396C91D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				7958155B1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
+				79F4678B1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D81D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C61D48C02300086753 /* SMB2FileOperation.swift in Sources */,
 				79BD63C91E2D17880035128C /* OneDriveHelper.swift in Sources */,
@@ -548,10 +582,12 @@
 				799396E11D48C02300086753 /* WebDAVFileProvider.swift in Sources */,
 				799396DB1D48C02300086753 /* SMBErrorType.swift in Sources */,
 				799396C31D48C02300086753 /* SMB2FileHandle.swift in Sources */,
+				793CCE2F1F4B8C7B00BC8288 /* HashMAC.swift in Sources */,
 				799396CC1D48C02300086753 /* SMB2Query.swift in Sources */,
 				7924B1AD1D89F7D800589DB7 /* SMBClient.swift in Sources */,
 				79BD638D1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				799396AB1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
+				793CCE2B1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */,
 				7924B1A61D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B11D48C02300086753 /* FileProvider.swift in Sources */,
 				7924B19D1D89DAE000589DB7 /* Error.swift in Sources */,
@@ -562,17 +598,19 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				796807571E7BF17E00BBB87B /* FileProviderExtensions.swift in Sources */,
 				799396B51D48C02300086753 /* LocalFileProvider.swift in Sources */,
 				799396D61D48C02300086753 /* SMB2Tree.swift in Sources */,
 				7924B1A41D89DAE000589DB7 /* Options.swift in Sources */,
 				792572431DF23BDA006A1526 /* LocalHelper.swift in Sources */,
+				7936BC141E880F5700A6C81C /* FTPFileProvider.swift in Sources */,
 				79480FF81E3ABDD0007E7275 /* CloudFileProvider.swift in Sources */,
 				79F5745D1DFDB10B00179ABF /* FileObject.swift in Sources */,
-				79BD63C71E2D17880035128C /* OneDriveFileProvide.swift in Sources */,
+				79BD63C71E2D17880035128C /* OneDriveFileProvider.swift in Sources */,
 				7924B1B11D89F7DF00589DB7 /* FPSStreamTask.swift in Sources */,
 				7924B19B1D89DAE000589DB7 /* Element.swift in Sources */,
 				799396CA1D48C02300086753 /* SMB2IOCtl.swift in Sources */,
+				7958155C1F478ED9003344DD /* HTTPFileProvider.swift in Sources */,
+				79F4678C1E8B80F200C91A85 /* FTPHelper.swift in Sources */,
 				799396D91D48C02300086753 /* SMB2Types.swift in Sources */,
 				799396C71D48C02300086753 /* SMB2FileOperation.swift in Sources */,
 				79BD63CA1E2D17880035128C /* OneDriveHelper.swift in Sources */,
@@ -589,10 +627,12 @@
 				799396E21D48C02300086753 /* WebDAVFileProvider.swift in Sources */,
 				799396DC1D48C02300086753 /* SMBErrorType.swift in Sources */,
 				799396C41D48C02300086753 /* SMB2FileHandle.swift in Sources */,
+				793CCE301F4B8C7B00BC8288 /* HashMAC.swift in Sources */,
 				799396CD1D48C02300086753 /* SMB2Query.swift in Sources */,
 				7924B1AE1D89F7D900589DB7 /* SMBClient.swift in Sources */,
 				79BD638E1E2CC2300035128C /* ExtendedLocalFileProvider.swift in Sources */,
 				799396AC1D48C02300086753 /* DropboxFileProvider.swift in Sources */,
+				793CCE2C1F4B8C5C00BC8288 /* FoundationExtensions.swift in Sources */,
 				7924B1A71D89DAE000589DB7 /* Parser.swift in Sources */,
 				799396B21D48C02300086753 /* FileProvider.swift in Sources */,
 				7924B19E1D89DAE000589DB7 /* Error.swift in Sources */,
@@ -605,7 +645,7 @@
 		799396601D48B7BF00086753 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.14.4;
+				BUNDLE_VERSION_STRING = 0.21.0;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -615,6 +655,7 @@
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				COPY_PHASE_STRIP = NO;
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				ENABLE_BITCODE = YES;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
@@ -628,6 +669,7 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				ONLY_ACTIVE_ARCH = YES;
+				PRODUCT_NAME = FilesProvider;
 				SWIFT_VERSION = 3.0;
 			};
 			name = Debug;
@@ -635,7 +677,7 @@
 		799396611D48B7BF00086753 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.14.4;
+				BUNDLE_VERSION_STRING = 0.21.0;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -655,6 +697,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
+				PRODUCT_NAME = FilesProvider;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 				SWIFT_VERSION = 3.0;
 			};
@@ -665,7 +708,6 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				APPLICATION_EXTENSION_API_ONLY = YES;
-				BUNDLE_VERSION_STRING = 0.8.2;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
@@ -702,8 +744,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-iOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-iOS";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -718,7 +759,6 @@
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				APPLICATION_EXTENSION_API_ONLY = YES;
-				BUNDLE_VERSION_STRING = 0.8.2;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
@@ -750,8 +790,7 @@
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = NO;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-iOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-iOS";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
 				TARGETED_DEVICE_FAMILY = "1,2";
@@ -807,8 +846,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/Frameworks";
 				MACOSX_DEPLOYMENT_TARGET = 10.10;
 				MTL_ENABLE_DEBUG_INFO = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-OSX";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-OSX";
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -858,8 +896,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/Frameworks";
 				MACOSX_DEPLOYMENT_TARGET = 10.10;
 				MTL_ENABLE_DEBUG_INFO = NO;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-OSX";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-OSX";
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
 				VERSIONING_SYSTEM = "apple-generic";
@@ -910,8 +947,7 @@
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = YES;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-tvOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-tvOS";
 				SDKROOT = appletvos;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -960,8 +996,7 @@
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MTL_ENABLE_DEBUG_INFO = NO;
-				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FileProvider-tvOS";
-				PRODUCT_NAME = FileProvider;
+				PRODUCT_BUNDLE_IDENTIFIER = "com.mousavian.FilesProvider-tvOS";
 				SDKROOT = appletvos;
 				SKIP_INSTALL = YES;
 				TARGETED_DEVICE_FAMILY = 3;
@@ -975,7 +1010,7 @@
 /* End XCBuildConfiguration section */

 /* Begin XCConfigurationList section */
-		7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FileProvider" */ = {
+		7993965F1D48B7BF00086753 /* Build configuration list for PBXProject "FilesProvider" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				799396601D48B7BF00086753 /* Debug */,
@@ -984,7 +1019,7 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
-		7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FileProvider iOS" */ = {
+		7993966F1D48B7F600086753 /* Build configuration list for PBXNativeTarget "FilesProvider iOS" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				7993966D1D48B7F600086753 /* Debug */,
@@ -993,7 +1028,7 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
-		7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FileProvider OSX" */ = {
+		7993967A1D48B80D00086753 /* Build configuration list for PBXNativeTarget "FilesProvider OSX" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				7993967B1D48B80D00086753 /* Debug */,
@@ -1002,7 +1037,7 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
-		799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FileProvider tvOS" */ = {
+		799396871D48B82700086753 /* Build configuration list for PBXNativeTarget "FilesProvider tvOS" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
 				799396881D48B82700086753 /* Debug */,
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0810"
+   LastUpgradeVersion = "0820"
   version = "1.3">
   <BuildAction
      parallelizeBuildables = "YES"
@@ -15,9 +15,9 @@
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "799396741D48B80D00086753"
-               BuildableName = "FileProvider.framework"
-               BlueprintName = "FileProvider OSX"
-               ReferencedContainer = "container:FileProvider.xcodeproj">
+               BuildableName = "FilesProvider.framework"
+               BlueprintName = "FilesProvider OSX"
+               ReferencedContainer = "container:FilesProvider.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
@@ -26,6 +26,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
@@ -36,6 +37,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
@@ -46,9 +48,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396741D48B80D00086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider OSX"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider OSX"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
@@ -64,9 +66,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396741D48B80D00086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider OSX"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider OSX"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
   </ProfileAction>
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0810"
+   LastUpgradeVersion = "0820"
   version = "1.3">
   <BuildAction
      parallelizeBuildables = "YES"
@@ -15,9 +15,9 @@
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "799396661D48B7F600086753"
-               BuildableName = "FileProvider.framework"
-               BlueprintName = "FileProvider iOS"
-               ReferencedContainer = "container:FileProvider.xcodeproj">
+               BuildableName = "FilesProvider.framework"
+               BlueprintName = "FilesProvider iOS"
+               ReferencedContainer = "container:FilesProvider.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
@@ -26,6 +26,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
@@ -36,6 +37,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
@@ -46,9 +48,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396661D48B7F600086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider iOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider iOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
@@ -64,9 +66,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396661D48B7F600086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider iOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider iOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
   </ProfileAction>
@@ -15,9 +15,9 @@
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "799396811D48B82700086753"
-               BuildableName = "FileProvider.framework"
-               BlueprintName = "FileProvider tvOS"
-               ReferencedContainer = "container:FileProvider.xcodeproj">
+               BuildableName = "FilesProvider.framework"
+               BlueprintName = "FilesProvider tvOS"
+               ReferencedContainer = "container:FilesProvider.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
@@ -26,6 +26,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
@@ -36,6 +37,7 @@
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
@@ -46,9 +48,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396811D48B82700086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider tvOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider tvOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
@@ -64,9 +66,9 @@
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "799396811D48B82700086753"
-            BuildableName = "FileProvider.framework"
-            BlueprintName = "FileProvider tvOS"
-            ReferencedContainer = "container:FileProvider.xcodeproj">
+            BuildableName = "FilesProvider.framework"
+            BlueprintName = "FilesProvider tvOS"
+            ReferencedContainer = "container:FilesProvider.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
   </ProfileAction>
@@ -1,5 +1,5 @@
 import PackageDescription

 let package = Package(
-    name: "FileProvider"
-)
+    name: "FilesProvider"
+)
@@ -2,60 +2,70 @@

 >This Swift library provide a swifty way to deal with local and remote files and directories in a unified way.

+<center>
+
 [![Swift Version][swift-image]][swift-url]
 [![Platform][platform-image]](#)
 [![License][license-image]][license-url]
-
-[![Release versin][release-image]][release-url]
-[![CocoaPods version](https://img.shields.io/cocoapods/v/FileProvider.svg)][cocoapods]
-[![Carthage compatible][carthage-image]](https://github.com/Carthage/Carthage)
-
 [![Build Status][travis-image]][travis-url]
 [![Codebeat Badge][codebeat-image]][codebeat-url]
-[![Cocoapods Docs][docs-image]][docs-url]
+
+[![Release version][release-image]][release-url]
+[![CocoaPods version](https://img.shields.io/cocoapods/v/FilesProvider.svg)][cocoapods]
+[![Carthage compatible][carthage-image]](https://github.com/Carthage/Carthage)
 [![Cocoapods Downloads][cocoapods-downloads]][cocoapods]
 [![Cocoapods Apps][cocoapods-apps]][cocoapods]

+Old Cocoapods repo stats:
+[![Cocoapods Downloads][cocoapods-downloads-old]][cocoapods-old]
+[![Cocoapods Apps][cocoapods-apps-old]][cocoapods-old]
+
+</center>
+
 <!--- 
+[![Cocoapods Doc][docs-image]][docs-url]
 [![codecov](https://codecov.io/gh/amosavian/FileProvider/branch/master/graph/badge.svg)](https://codecov.io/gh/amosavian/FileProvider) 
 ---> 

-This library provides implementaion of WebDav, Dropbox, OneDrive and SMB2 (incomplete) and local files.
+This library provides implementaion of WebDav, FTP, Dropbox, OneDrive and SMB2 (incomplete) and local files.

-All functions are async calls and it wont block your main thread.
+All functions do async calls and it wont block your main thread.

 ## Features

- [x] **LocalFileProvider** a wrapper around `FileManager` with some additions like searching and reading a portion of file.
- [x] **CloudFileProvider** A wrapper around app's ubiquitous container to iCloud Drive in iOS 8+ API.
- [x] **WebDAVFileProvider** WebDAV protocol is defacto file transmission standard, replaced FTP.
+- [x] **LocalFileProvider** a wrapper around `FileManager` with some additions like builtin coordinating, searching and reading a portion of file.
+- [x] **CloudFileProvider** A wrapper around app's ubiquitous container API of iCloud Drive.
+- [x] **WebDAVFileProvider** WebDAV protocol is defacto file transmission standard, supported by some cloud services like `ownCloud`, `Box.com` and `Yandex.disk`.
+- [x] **FTPFileProvider** While deprecated in 1990s due to serious security concerns, it's still in use on some Web hosts.
 - [x] **DropboxFileProvider** A wrapper around Dropbox Web API.
    * For now it has limitation in uploading files up to 150MB.
 - [x] **OneDriveFileProvider** A wrapper around OneDrive REST API, works with `onedrive.com` and compatible (business) servers.
    * For now it has limitation in uploading files up to 100MB.
- [ ] **GoogleFileProvider** A wrapper around Goodle Drive REST API.
 - [ ] **AmazonS3FileProvider** Amazon storage backend. Used by many sites.
+- [ ] **GoogleFileProvider** A wrapper around Goodle Drive REST API.
 - [ ] **SMBFileProvider** SMB2/3 introduced in 2006, which is a file and printer sharing protocol originated from Microsoft Windows and now is replacing AFP protocol on macOS.
    * Data types and some basic functions are implemented but *main interface is not implemented yet!*.
-    * SMB1/CIFS is deprecated and very tricky to be implemented.
- [ ] **FTPFileProvider** while deprecated in 1990s, it's still in use on some Web hosts.
+    * SMBv1/CIFS is insecure, deprecated and kinda tricky to be implemented due to strict memory allignment in Swift.

 ## Requirements

- **Swift 3.0 +**
+- **Swift 3.0 or higher**
 - iOS 8.0 , OSX 10.10
 - XCode 8.0

-Legacy version is available in swift-2 branch
+Legacy version is available in swift-2 branch.

 ## Installation

+### Important: this library has been renamed to avoid conflict in iOS 11, macOS 10.13 and Xcode 9.0. Please read issue [#53](https://github.com/amosavian/FileProvider/issues/53) to find more.
+
+
 ### Cocoapods / Carthage / Swift Package Manager

 Add this line to your pods file:

 ```ruby
-pod "FileProvider"
+pod "FilesProvider"
 ```

 Or add this to Cartfile:
@@ -67,7 +77,7 @@ github "amosavian/FileProvider"
 Or to use in Swift Package Manager add this line in `Dependencies`:

 ```swift
-.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0, minorVersion: 12)
+.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0)
 ```

 ### Manually
@@ -93,7 +103,7 @@ Then you can do either:

 * Copy Source folder to your project and Voila!

-* Drop `FileProvider.xcodeproj` to you Xcode workspace and add the framework to your Embeded Binaries in target.
+* Drop `FilesProvider.xcodeproj` to you Xcode workspace and add the framework to your Embeded Binaries in target.

 ## Usage

@@ -104,6 +114,8 @@ Each provider has a specific class which conforms to FileProvider protocol and s
 For LocalFileProvider if you want to deal with `Documents` folder

 ```	swift
+import FilesProvider
+
 let documentsProvider = LocalFileProvider()

 // Equals with:
@@ -117,6 +129,8 @@ let documentsProvider = LocalFileProvider(baseURL: documentsURL)
 Also for using group shared container:

 ```swift
+import FilesProvider
+
 let documentsProvider = LocalFileProvider(sharedContainerId: "group.yourcompany.appContainer")
 // Replace your group identifier
 ```
@@ -126,6 +140,8 @@ You can't change the base url later. and all paths are related to this base url
 To initialize an iCloud Container provider look at [here](https://medium.com/ios-os-x-development/icloud-drive-documents-1a46b5706fe1) to see how to update project settings then use below code, This will automatically manager creating Documents folder in container:

 ```swift
+import FilesProvider
+
 let documentsProvider = CloudFileProvider(containerId: nil)
 ```

@@ -133,11 +149,13 @@ let documentsProvider = CloudFileProvider(containerId: nil)
 For remote file providers authentication may be necessary:

 ```	swift
+import FilesProvider
+
 let credential = URLCredential(user: "user", password: "pass", persistence: .permanent)
 let webdavProvider = WebDAVFileProvider(baseURL: URL(string: "http://www.example.com/dav")!, credential: credential)
 ```

-* In case you want to connect non-secure servers for WebDAV (http) in iOS 9+ / macOS 10.11+ you should disable App Transport Security (ATS) according to [this guide.](https://gist.github.com/mlynch/284699d676fe9ed0abfa)
+* In case you want to connect non-secure servers for WebDAV (http) or FTP in iOS 9+ / macOS 10.11+ you should disable App Transport Security (ATS) according to [this guide.](https://gist.github.com/mlynch/284699d676fe9ed0abfa)

 * For Dropbox & OneDrive, user is clientID and password is Token which both must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide). There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. The latter is easier to use and prefered.
 	
@@ -149,7 +167,7 @@ You can use `url(of:)` method if provider to get direct access url (local or rem

 For updating User interface please consider using delegate method instead of completion handlers. Delegate methods are guaranteed to run in main thread to avoid bugs.

-It's simply three method which indicated whether the operation failed, succeed and how much of operation has been done (suitable for uploading and downloading operations).
+There's simply three method which indicated whether the operation failed, succeed and how much of operation has been done (suitable for uploading and downloading operations).

 Your class should conforms `FileProviderDelegate` class:

@@ -202,7 +220,7 @@ You can also implement `FileOperationDelegate` protocol to control behaviour of

 `fileProvider(shouldProceedAfterError:, operation:)` will be called if an error occured during file operations. Return `true` if you want to continue operation on next files or `false` if you want stop operation further. Default value is false if you don't implement delegate.

-**Note: these methods will be called for files in a directory and its subfolders recursively.**
+**Note: In `LocalFileProvider`, these methods will be called for files in a directory and its subfolders recursively.**

 ### Directory contents and file attributes

@@ -228,10 +246,10 @@ To get list of files in a directory:
 documentsProvider.contentsOfDirectory(path: "/", completionHandler: {
 	contents, error in
 	for file in contents {
-		print("Name: \(attributes.name)")
-		print("Size: \(attributes.size)")
-		print("Creation Date: \(attributes.creationDate)")
-		print("Modification Date: \(attributes.modifiedDate)")
+		print("Name: \(file.name)")
+		print("Size: \(file.size)")
+		print("Creation Date: \(file.creationDate)")
+		print("Modification Date: \(file.modifiedDate)")
 	}
 })
 ```
@@ -248,15 +266,6 @@ func storageProperties(completionHandler: { total, used in
 	
 * if this function is unavailable on provider or an error has been occurred, total space will be reported `-1` and used space `0`

-### Change current directory
-
-```swift
-documentsProvider.currentPath = "/New Folder"
-// now path is ~/Documents/New Folder
-```
-	
-You can then pass "" (empty string) to `contentsOfDirectory` method to list files in current directory.
-
 ### Creating File and Folders

 Creating new directory:
@@ -271,12 +280,7 @@ documentsProvider.create(folder: "new folder", at: "/", completionHandler: { err
 })
 ```

-Creating new file from data:
-
-```swift
-let data = "hello world!".data(encoding: .utf8)
-documentsProvider.create(file: "newFile.txt", at: "/", contents: data, completionHandler: nil)
-```
+To create a file, use `writeContents(path:, content:, atomically:, completionHandler:)` method.

 ### Copy and Move/Rename Files

@@ -300,11 +304,9 @@ documentsProvider.moveItem(path: "new folder/old.txt", to: "new.txt", overwrite:
 documentsProvider.removeItem(path: "new.txt", completionHandler: nil)
 ```

-***Caution:*** This method will delete directories with all it's contents recursively.
-
 ### Fetching Contents of File

-There is two method for this purpose, one of them loads entire file into NSData and another can load a portion of file.
+There is two method for this purpose, one of them loads entire file into `Data` and another can load a portion of file.

 ```swift
 documentsProvider.contents(path: "old.txt", completionHandler: {
@@ -333,6 +335,33 @@ let data = "What's up Newyork!".data(encoding: .utf8)
 documentsProvider.writeContents(path: "old.txt", content: data, atomically: true, completionHandler: nil)
 ```

+### Copying Files to and From Local Storage
+
+There are two methods to download and upload files between provider's and local storage. These methods use `URLSessionDownloadTask` and `URLSessionUploadTask` classes and allows to use background session and provide progress via delegate.
+
+To upload a file:
+
+```swift
+let fileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image.jpg")
+documentsProvider.copyItem(localFile: fileURL, to: "/upload/image.jpg", overwrite: true, completionHandler: nil)
+```
+
+To download a file:
+
+```swift
+let fileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("image.jpg")
+documentsProvider.copyItem(path: "/download/image.jpg", toLocalURL: fileURL, overwrite: true, completionHandler: nil)
+```
+
+* It's safe only to assume these methods **won't** handle directories to upload/download recursively. If you need, you can list directories, create directories on target and copy files using these methods.
+* FTP provider allows developer to either use apple implemented `URLSessionDownloadTask` or custom implemented method based on stream task via `useAppleImplementation` property. FTP protocol is not supported by background session.
+
+### Operation Progress
+
+Creating/Copying/Deleting/Searching functions return a `(NS)Progress`. It provides operation type, progress and a `.cancel()` method which allows you to cancel operation in midst. You can check `cancellable` property to check either you can cancel operation via this object or not.
+
+- **Note:** Progress reporting is not supported by native `(NS)FileManager` so `LocalFileProvider`.
+
 ### Undo Operations

 Providers conform to `FileProviderUndoable` can perform undo for **some** operations like moving/renaming, copying and creating (file or folder). **Now, only `LocalFileProvider` supports this feature.** To implement:
@@ -376,11 +405,9 @@ class ViewController: UIViewController
 }
 ```

-### Operation Handle
+### File Coordination

-Creating/Copying/Deleting functions return a `OperationHandle` for remote operations. It provides operation type, progress and a `.cancel()` method which allows you to cancel operation in midst.
-
-It's not supported by native `(NS)FileManager` so `LocalFileProvider`, but this functionality will be added to future `PosixFileProvider` class.
+`LocalFileProvider` and its descendents has a `isCoordinating` property. By setting this, provider will use `NSFileCoordinating` class to do all file operations. It's mandatory for iCloud, while recommended when using shared container or anywhere that simultaneous operations on a file/folder is common.

 ### Monitoring File Changes

@@ -388,12 +415,12 @@ You can monitor updates in some file system (Local and SMB2), there is three met

 ```swift
 // to register a new notification handler
-documentsProvider.registerNotifcation(path: provider.currentPath) {
+documentsProvider.registerNotifcation(path: "/") {
 	// calling functions to update UI 
 }
 	
 // To discontinue monitoring folders:
-documentsProvider.unregisterNotifcation(path: provider.currentPath)
+documentsProvider.unregisterNotifcation(path: "/")
 ```

 * **Please note** in LocalFileProvider it will also monitor changes in subfolders. This behaviour can varies according to file system specification.
@@ -409,9 +436,10 @@ To check either file thumbnail is supported or not and fetch thumbnail, use (and

 ```swift
 let path = "/newImage.jpg"
-let thumbSize = CGSize(width: 64, height: 64)
+let thumbSize = CGSize(width: 64, height: 64) // or nil which renders to default dimension of provider
 if documentsProvider.thumbnailOfFileSupported(path: path {
    documentsProvider.thumbnailOfFile(path: file.path, dimension: thumbSize, completionHandler: { (image, error) in
+        // Interacting with UI must be placed in main thread
        DispatchQueue.main.async {
            self.previewImage.image = image
        }
@@ -439,9 +467,10 @@ if documentsProvider..propertiesOfFile(path: file.path, completionHandler: { (pr

 We would love for you to contribute to **FileProvider**, check the `LICENSE` file for more info.

-Things to do:
+Things you may consider to help us:

- [ ] Implement Test-case (XCTest)
+- [ ] Implement request/response stack for `SMBClient`
+- [ ] Implement Test-case (`XCTest`)
 - [ ] Add Sample project for iOS
 - [ ] Add Sample project for macOS

@@ -462,10 +491,11 @@ Distributed under the MIT license. See `LICENSE` for more information.

 [https://github.com/amosavian/](https://github.com/amosavian/)

-[cocoapods]: https://cocoapods.org/pods/FileProvider
-[swift-image]: https://img.shields.io/badge/swift-3.0-orange.svg
+[cocoapods]: https://cocoapods.org/pods/FilesProvider
+[cocoapods-old]: https://cocoapods.org/pods/FileProvider
+[swift-image]: https://img.shields.io/badge/swift-3.0,%203.1-orange.svg
 [swift-url]: https://swift.org/
-[platform-image]: https://img.shields.io/cocoapods/p/FileProvider.svg
+[platform-image]: https://img.shields.io/cocoapods/p/FilesProvider.svg
 [license-image]: https://img.shields.io/github/license/amosavian/FileProvider.svg
 [license-url]: LICENSE
 [codebeat-image]: https://codebeat.co/badges/7b359f48-78eb-4647-ab22-56262a827517
@@ -475,7 +505,9 @@ Distributed under the MIT license. See `LICENSE` for more information.
 [release-url]: https://github.com/amosavian/FileProvider/releases
 [release-image]: https://img.shields.io/github/release/amosavian/FileProvider.svg
 [carthage-image]: https://img.shields.io/badge/Carthage-compatible-4BC51D.svg
-[cocoapods-downloads]: https://img.shields.io/cocoapods/dt/FileProvider.svg
-[cocoapods-apps]: https://img.shields.io/cocoapods/at/FileProvider.svg
-[docs-image]: https://img.shields.io/cocoapods/metrics/doc-percent/FileProvider.svg
-[docs-url]: http://cocoadocs.org/docsets/FileProvider/
+[cocoapods-downloads-old]: https://img.shields.io/cocoapods/dt/FileProvider.svg
+[cocoapods-apps-old]: https://img.shields.io/cocoapods/at/FileProvider.svg
+[cocoapods-downloads]: https://img.shields.io/cocoapods/dt/FilesProvider.svg
+[cocoapods-apps]: https://img.shields.io/cocoapods/at/FilesProvider.svg
+[docs-image]: https://img.shields.io/cocoapods/metrics/doc-percent/FilesProvider.svg
+[docs-url]: http://cocoadocs.org/docsets/FilesProvider/
@@ -0,0 +1,19 @@
+Copyright (c) 2014-2017 Marko Tadić <tadija@me.com> http://tadija.net
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
@@ -15,7 +15,7 @@ import Foundation
 To setup a functional iCloud container, please
 [read this page](https://medium.com/ios-os-x-development/icloud-drive-documents-1a46b5706fe1).
 */
-open class CloudFileProvider: LocalFileProvider {
+open class CloudFileProvider: LocalFileProvider, FileProviderSharing {
    /// An string to identify type of provider.
    open override class var type: String { return "iCloudDrive" }
    
@@ -26,8 +26,7 @@ open class CloudFileProvider: LocalFileProvider {
            return true
        }
        set {
-            assert(true, "CloudFileProvider.isCoorinating can't be set")
-            return
+            assert(newValue, "CloudFileProvider.isCoorinating can't be set to false")
        }
    }
    
@@ -51,16 +50,15 @@ open class CloudFileProvider: LocalFileProvider {
         If you specify nil for this parameter, this method uses the first container listed in the `com.apple.developer.ubiquity-container-identifiers` entitlement array.
     - Parameter scope: Use `.documents` (default) to put documents that the user is allowed to access inside a Documents subdirectory. Otherwise use `.data` to store user-related data files that your app needs to share but that are not files you want the user to manipulate directly.
    */
-    public init? (containerId: String?, scope: UbiquitousScope = .documents) {
-        assert(!CloudFileProvider.asserting || !Thread.isMainThread, "LocalFileProvider.init(containerId:) is not recommended to be executed on Main Thread.")
+    public convenience init? (containerId: String?, scope: UbiquitousScope = .documents) {
+        assert(!(CloudFileProvider.asserting && Thread.isMainThread), "CloudFileProvider.init(containerId:) is not recommended to be executed on Main Thread.")
        guard FileManager.default.ubiquityIdentityToken != nil else {
            return nil
        }
        guard let ubiquityURL = FileManager.default.url(forUbiquityContainerIdentifier: containerId) else {
            return nil
        }
-        self.containerId = containerId
-        self.scope = scope
+
        let baseURL: URL
        if scope == .documents {
            baseURL = ubiquityURL.appendingPathComponent("Documents/")
@@ -68,85 +66,79 @@ open class CloudFileProvider: LocalFileProvider {
            baseURL = ubiquityURL
        }
        
-        super.init(baseURL: baseURL)
-        self.isCoorinating = true
-        
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
-        operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
+        self.init(baseURL: baseURL)
+        self.containerId = containerId
+        self.scope = scope
        
+        // To prepare FileManager objects?!
        fileManager.url(forUbiquityContainerIdentifier: containerId)
        opFileManager.url(forUbiquityContainerIdentifier: containerId)
        
        try? fileManager.createDirectory(at: baseURL, withIntermediateDirectories: true)
    }
    
+    public override init(baseURL: URL) {
+        self.scope = .data
+        super.init(baseURL: baseURL)
+        self.isCoorinating = true
+        
+        #if swift(>=3.1)
+            let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+            let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        if let containerId = aDecoder.decodeObject(forKey: "containerId") as? String,
+            let scopeString = aDecoder.decodeObject(forKey: "scope") as? String,
+            let scope = UbiquitousScope(rawValue: scopeString) {
+            self.init(containerId: containerId, scope: scope)
+        } else if let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL {
+            self.init(baseURL: baseURL)
+        } else {
+            return nil
+        }
+        
+        self.isCoorinating = aDecoder.decodeBool(forKey: "isCoorinating")
+    }
+    
+    open override func encode(with aCoder: NSCoder) {
+        super.encode(with: aCoder)
+        aCoder.encode(self.containerId, forKey: "containerId")
+        aCoder.encode(self.scope.rawValue, forKey: "scope")
+    }
+    
+    open override func copy(with zone: NSZone? = nil) -> Any {
+        let copy = CloudFileProvider(containerId: self.containerId, scope: self.scope)
+        copy?.delegate = self.delegate
+        copy?.fileOperationDelegate = self.fileOperationDelegate
+        return copy as Any
+    }
+    
    /**
     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
     
     If the directory contains no entries or an error is occured, this method will return the empty array.
     
-     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
-     - Parameter completionHandler: a closure with result of directory entries or error.
-         `contents`: An array of `FileObject` identifying the the directory entries.
-         `error`: Error returned by system.
+     - Parameters:
+       - path: path to target directory. If empty, root will be iterated.
+       - completionHandler: a closure with result of directory entries or error.
+       - contents: An array of `FileObject` identifying the the directory entries.
+       - error: Error returned by system.
     */
-    open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
        // FIXME: create runloop for dispatch_queue, start query on it
-        dispatch_queue.async {
-            let pathURL = self.url(of: path)
-            
-            let query = NSMetadataQuery()
-            query.predicate = NSPredicate(format: "%K BEGINSWITH %@", NSMetadataItemPathKey, pathURL.path)
-            query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
-            query.searchScopes = [self.scope.rawValue]
-            var finishObserver: NSObjectProtocol?
-            finishObserver = NotificationCenter.default.addObserver(forName: NSNotification.Name.NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
-                defer {
-                    query.stop()
-                    NotificationCenter.default.removeObserver(finishObserver!)
-                }
-                
-                guard let results = query.results as? [NSMetadataItem] else {
-                    return
-                }
-                
-                query.disableUpdates()
-                
-                var contents = [FileObject]()
-                for result in results {
-                    guard let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
-                        continue
-                    }
-                    
-                    guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardized, url.deletingLastPathComponent().path.trimmingCharacters(in: pathTrimSet) == pathURL.path.trimmingCharacters(in: pathTrimSet) else {
-                        continue
-                    }
-                    
-                    if let file = self.mapFileObject(attributes: attribs) {
-                        contents.append(file)
-                    }
-                }
-                
-                query.stop()
-                self.dispatch_queue.async {
-                    completionHandler(contents, nil)
-                }
-                
-            })
-            DispatchQueue.main.async {
-                if !query.start() {
-                    self.dispatch_queue.async {
-                        completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
-                    }
-                }
-            }
-        }
+        let query = NSPredicate(format: "TRUEPREDICATE")
+        _ = searchFiles(path: path, recursive: false, query: query, foundItemHandler: nil, completionHandler: completionHandler)
    }
    
    /// Please don't rely this function to get iCloud drive total and remaining capacity
    /// - Important: iCloud Storage size and free space is unavailable, it returns local space
-    open override func storageProperties(completionHandler: (@escaping (_ total: Int64, _ used: Int64) -> Void)) {
+    open override func storageProperties(completionHandler: @escaping (VolumeObject?) -> Void) {
        super.storageProperties(completionHandler: completionHandler)
    }
    
@@ -155,20 +147,21 @@ open class CloudFileProvider: LocalFileProvider {
     
     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
     
-     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
-     - Parameter completionHandler: a closure with result of directory entries or error.
-         `attributes`: A `FileObject` containing the attributes of the item.
-         `error`: Error returned by system.
+     - Parameters:
+       - path: path to target directory. If empty, attributes of root will be returned.
+       - completionHandler: a closure with result of directory entries or error.
+       - attributes: A `FileObject` containing the attributes of the item.
+       - error: Error returned by system.
     */
-    open override func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    open override func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
        dispatch_queue.async {
            let pathURL = self.url(of: path)
            let query = NSMetadataQuery()
-            query.predicate = NSPredicate(format: "%K LIKE %@", NSMetadataItemPathKey, pathURL.path)
+            query.predicate = NSPredicate(format: "%K LIKE[CD] %@", NSMetadataItemPathKey, pathURL.path)
            query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
            query.searchScopes = [self.scope.rawValue]
            var finishObserver: NSObjectProtocol?
-            finishObserver = NotificationCenter.default.addObserver(forName: NSNotification.Name.NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
                defer {
                    query.stop()
                    NotificationCenter.default.removeObserver(finishObserver!)
@@ -177,7 +170,7 @@ open class CloudFileProvider: LocalFileProvider {
                query.disableUpdates()
                
                guard let result = (query.results as? [NSMetadataItem])?.first, let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
-                    let error = self.throwError(path, code: CocoaError.fileNoSuchFile)
+                    let error = self.cocoaError(path, code: .fileNoSuchFile)
                    self.dispatch_queue.async {
                        completionHandler(nil, error)
                    }
@@ -189,7 +182,7 @@ open class CloudFileProvider: LocalFileProvider {
                        completionHandler(file, nil)
                    }
                } else {
-                    let noFileError = self.throwError(path, code: CocoaError.fileNoSuchFile)
+                    let noFileError = self.cocoaError(path, code: .fileNoSuchFile)
                    self.dispatch_queue.async {
                        completionHandler(nil, noFileError)
                    }
@@ -198,7 +191,7 @@ open class CloudFileProvider: LocalFileProvider {
            DispatchQueue.main.async {
                if !query.start() {
                    self.dispatch_queue.async {
-                        completionHandler(nil, self.throwError(path, code: CocoaError.fileReadNoPermission))
+                        completionHandler(nil, self.cocoaError(path, code: .fileReadNoPermission))
                    }
                }
            }
@@ -208,101 +201,51 @@ open class CloudFileProvider: LocalFileProvider {
    /**
     Search files inside directory using query asynchronously.
     
-     - Note: For now only it's limited to file names. `query` parameter may take `NSPredicate` format in near future.
+     Sample predicates:
+     ```
+     NSPredicate(format: "(name CONTAINS[c] 'hello') && (filesize >= 10000)")
+     NSPredicate(format: "(modifiedDate >= %@)", Date())
+     NSPredicate(format: "(path BEGINSWITH %@)", "folder/child folder")
+     ```
+     
+     - Note: Don't pass Spotlight predicates to this method directly, use `FileProvider.convertSpotlightPredicateTo()` method to get usable predicate.
+     
+     - Important: A file name criteria should be provided for Dropbox.
     
     - Parameters:
-     - path: location of directory to start search
-     - recursive: Searching subdirectories of path
-     - query: Simple string of file name to be search (for now).
-     - foundItemHandler: Closure which is called when a file is found
-     - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+       - path: location of directory to start search
+       - recursive: Searching subdirectories of path
+       - query: An `NSPredicate` object with keys like `FileObject` members, except `size` which becomes `filesize`.
+       - foundItemHandler: Closure which is called when a file is found
+       - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+       - files: all files meat the `query` criteria.
+       - error: `Error` returned by server if occured.
+     - Returns: An `Progress` to get progress or cancel progress. Use `completedUnitCount` to iterate count of found items.
     */
-    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let progress = Progress(totalUnitCount: -1)
        
-        let mapDict: [String: String] = ["url": NSMetadataItemURLKey, "name": NSMetadataItemFSNameKey, "path": NSMetadataItemPathKey, "filesize": NSMetadataItemFSSizeKey, "modifiedDate": NSMetadataItemFSContentChangeDateKey, "creationDate": NSMetadataItemFSCreationDateKey, "contentType": NSMetadataItemContentTypeKey]
+        let pathURL = self.url(of: path)
+        progress.setUserInfoObject(pathURL, forKey: .fileURLKey)
+        let mdquery = NSMetadataQuery()
+        mdquery.predicate = NSPredicate(format: "(%K BEGINSWITH[CD] %@) && (\(updateQueryTypeKeys(query).predicateFormat))", NSMetadataItemPathKey, pathURL.path)
+        mdquery.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]
+        mdquery.searchScopes = [self.scope.rawValue]
        
-        func updateQueryKeys(_ queryComponent: NSPredicate) -> NSPredicate {
-            if let cQuery = queryComponent as? NSCompoundPredicate {
-                let newSub = cQuery.subpredicates.map { updateQueryKeys($0 as! NSPredicate) }
-                switch cQuery.compoundPredicateType {
-                case .and: return NSCompoundPredicate(andPredicateWithSubpredicates: newSub)
-                case .not: return NSCompoundPredicate(notPredicateWithSubpredicate: newSub.first!)
-                case .or:  return NSCompoundPredicate(orPredicateWithSubpredicates: newSub)
-                }
-            } else if let cQuery = queryComponent as? NSComparisonPredicate {
-                var newLeft = cQuery.leftExpression
-                var newRight = cQuery.rightExpression
-                if newLeft.expressionType == .keyPath, let newKey = mapDict[newLeft.keyPath] {
-                    newLeft = NSExpression(forKeyPath: newKey)
-                }
-                if newRight.expressionType == .keyPath, let newKey = mapDict[newRight.keyPath] {
-                    newRight = NSExpression(forKeyPath: newKey)
-                }
-                if newLeft.expressionType == .keyPath, newLeft.keyPath == "type" {
-                    newRight = NSExpression(forConstantValue: newRight.constantValue as? String == "directory" ? "public.directory": "public.data")
-                }
-                if newRight.expressionType == .keyPath, newRight.keyPath == "type" {
-                    newLeft = NSExpression(forConstantValue: newLeft.constantValue as? String == "directory" ? "public.directory": "public.data")
-                }
-                return NSComparisonPredicate(leftExpression: newLeft, rightExpression: newRight, modifier: cQuery.comparisonPredicateModifier, type: cQuery.predicateOperatorType, options: cQuery.options)
-            } else {
-                return queryComponent
-            }
+        var lastReportedCount = 0
+        
+        progress.cancellationHandler = { [weak mdquery] in
+            mdquery?.stop()
        }
        
-        dispatch_queue.async {
-            let pathURL = self.url(of: path)
-            let mdquery = NSMetadataQuery()
-            mdquery.predicate = NSPredicate(format: "(%K BEGINSWITH %@) && (\(updateQueryKeys(query).predicateFormat))", NSMetadataItemPathKey, pathURL.path)
-            mdquery.searchScopes = [self.scope.rawValue]
-            
-            var lastReportedCount = 0
-            
-            if let foundItemHandler = foundItemHandler {
-                var updateObserver: NSObjectProtocol?
-                
-                // FIXME: Remove this section as it won't work as expected on iCloud
-                updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryGatheringProgress, object: mdquery, queue: nil, using: { (notification) in
-                    
-                    mdquery.disableUpdates()
-                    
-                    guard mdquery.resultCount > lastReportedCount else { return }
-                    
-                    for index in lastReportedCount..<mdquery.resultCount {
-                        guard let attribs = (mdquery.result(at: index) as? NSMetadataItem)?.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
-                            continue
-                        }
-                        
-                        guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardized, recursive || url.deletingLastPathComponent().path.trimmingCharacters(in: pathTrimSet) == pathURL.path.trimmingCharacters(in: pathTrimSet) else {
-                            continue
-                        }
-                        
-                        if let file = self.mapFileObject(attributes: attribs) {
-                            foundItemHandler(file)
-                        }
-                    }
-                    lastReportedCount = mdquery.resultCount
-                    
-                    mdquery.enableUpdates()
-                })
-            }
-            
-            var finishObserver: NSObjectProtocol?
-            finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: mdquery, queue: nil, using: { (notification) in
-                defer {
-                    mdquery.stop()
-                    NotificationCenter.default.removeObserver(finishObserver!)
-                }
-                
-                guard let results = mdquery.results as? [NSMetadataItem] else {
-                    return
-                }
-                
+        var updateObserver: NSObjectProtocol?
+        if let foundItemHandler = foundItemHandler {
+            // FIXME: Remove this section as it won't work as expected on iCloud
+            updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryGatheringProgress, object: mdquery, queue: nil, using: { (notification) in
                mdquery.disableUpdates()
                
-                var contents = [FileObject]()
-                for result in results {
-                    guard let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
+                for index in lastReportedCount..<mdquery.resultCount {
+                    guard let attribs = (mdquery.result(at: index) as? NSMetadataItem)?.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
                        continue
                    }
                    
@@ -310,23 +253,63 @@ open class CloudFileProvider: LocalFileProvider {
                        continue
                    }
                    
-                    if let file = self.mapFileObject(attributes: attribs) {
-                        contents.append(file)
+                    if let file = self.mapFileObject(attributes: attribs), query.evaluate(with: file.mapPredicate()) {
+                        foundItemHandler(file)
                    }
                }
-                self.dispatch_queue.async {
-                    completionHandler(contents, nil)
-                }
+                lastReportedCount = mdquery.resultCount
+                progress.totalUnitCount = Int64(lastReportedCount)
+                
+                mdquery.enableUpdates()
            })
+        }
+        
+        var finishObserver: NSObjectProtocol?
+        finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: mdquery, queue: nil, using: { (notification) in
+            defer {
+                mdquery.stop()
+                finishObserver.flatMap(NotificationCenter.default.removeObserver)
+                finishObserver = nil
+                updateObserver.flatMap(NotificationCenter.default.removeObserver)
+                updateObserver = nil
+            }
            
-            DispatchQueue.main.async {
-                if !mdquery.start() {
-                    self.dispatch_queue.async {
-                        completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
-                    }
+            guard let results = mdquery.results as? [NSMetadataItem] else {
+                return
+            }
+            
+            mdquery.disableUpdates()
+            
+            var contents = [FileObject]()
+            for result in results {
+                guard let attribs = result.values(forAttributes: [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataItemFSSizeKey, NSMetadataItemContentTypeTreeKey, NSMetadataItemFSCreationDateKey, NSMetadataItemFSContentChangeDateKey]) else {
+                    continue
+                }
+                
+                guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardized, recursive || url.deletingLastPathComponent().path.trimmingCharacters(in: pathTrimSet) == pathURL.path.trimmingCharacters(in: pathTrimSet) else {
+                    continue
+                }
+                
+                if let file = self.mapFileObject(attributes: attribs), query.evaluate(with: file.mapPredicate()) {
+                    contents.append(file)
+                }
+            }
+            progress.completedUnitCount = Int64(contents.count)
+            self.dispatch_queue.async {
+                completionHandler(contents, nil)
+            }
+        })
+        
+        DispatchQueue.main.async {
+            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            if !mdquery.start() {
+                self.dispatch_queue.async {
+                    completionHandler([], self.cocoaError(path, code: .fileReadNoPermission))
                }
            }
        }
+        
+        return progress
    }
    
    open override func isReachable(completionHandler: @escaping (Bool) -> Void) {
@@ -335,75 +318,6 @@ open class CloudFileProvider: LocalFileProvider {
        }
    }
    
-    /**
-     Creates a new directory at the specified path asynchronously.
-     This will create any necessary intermediate directories.
-     
-     - Parameters:
-       - folder: Directory name.
-       - at: Parent path of new directory.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.create(folder: folderName, at: atPath, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
-    }
-    
-    /**
-     Creates an new file with data passed to method asynchronously.
-     Returns error via completionHandler if file is already exists.
-     
-     - Parameters:
-       - file: New file name with extension separated by period.
-       - at: Parent path of new file.
-       - data: Data of new files. Pass nil or `Data()` to create empty file.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.create(file: fileName, at: atPath, contents: data, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
-    }
-    
-    /**
-     Moves a file or directory from `path` to designated path asynchronously.
-     When you want move a file, destination path should also consists of file name.
-     Either a new name or the old one.
-     
-     - Parameters:
-       - path: original file or directory path.
-       - to: destination path of file or directory, including file/directory name.
-       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
-    }
-    
-    /**
-     Copies a file or directory from `path` to designated path asynchronously.
-     When want copy a file, destination path should also consists of file name.
-     Either a new name or the old one.
-     
-     - Parameters:
-       - path: original file or directory path.
-       - to: destination path of file or directory, including file/directory name.
-       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     */
-    @discardableResult
-    open override func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
-    }
-    
    /**
     Removes the file or directory at the specified path.
     
@@ -414,13 +328,11 @@ open class CloudFileProvider: LocalFileProvider {
     - Parameters:
       - path: file or directory path.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
-     
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `CloudFileProvider`.
     */
    @discardableResult
-    open override func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.removeItem(path: path, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+    open override func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return super.removeItem(path: path, completionHandler: completionHandler)
    }
    
    /**
@@ -432,12 +344,19 @@ open class CloudFileProvider: LocalFileProvider {
       - to: destination path of file, including file/directory name.
       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress.
+     - Returns: A `Progress` object to get progress or cancel progress.
     */
    @discardableResult
-    open override func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open override func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        // TODO: Make use of overwrite parameter
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        let progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.isCancellable = false
+        progress.setUserInfoObject(localFile, forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: toPath, operation: operation, progress: progress)
        operation_queue.addOperation {
            let tempFolder: URL
            if #available(iOS 10.0, macOS 10.12, tvOS 10.0, *) {
@@ -448,24 +367,22 @@ open class CloudFileProvider: LocalFileProvider {
            let tmpFile = tempFolder.appendingPathComponent(UUID().uuidString)
            
            do {
+                progress.totalUnitCount = localFile.fileSize
                try self.opFileManager.copyItem(at: localFile, to: tmpFile)
                let toUrl = self.url(of: toPath)
                try self.opFileManager.setUbiquitous(true, itemAt: tmpFile, destinationURL: toUrl)
+                self.monitorFile(path: toPath, operation: operation, progress: progress)
                completionHandler?(nil)
-                DispatchQueue.main.async(execute: {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                })
-            } catch let e {
+                self.delegateNotify(operation)
+            } catch  {
                if self.opFileManager.fileExists(atPath: tmpFile.path) {
                    try? self.opFileManager.removeItem(at: tmpFile)
                }
-                completionHandler?(e)
-                DispatchQueue.main.async(execute: {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                })
+                completionHandler?(error)
+                self.delegateNotify(operation, error: error)
            }
        }
-        return CloudOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return progress
    }
    
    /**
@@ -476,24 +393,21 @@ open class CloudFileProvider: LocalFileProvider {
       - path: original file or directory path.
       - toLocalURL: destination local url of file, including file/directory name.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress.
+     - Returns: A `Progress` object to get progress or cancel progress.
     */
    @discardableResult
-    open override func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
-        
+    open override func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
+        let progress = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler)
+        monitorFile(path: path, operation: operation, progress: progress)
        do {
            try self.opFileManager.startDownloadingUbiquitousItem(at: self.url(of: path))
-        } catch let e {
-            completionHandler?(e)
-            DispatchQueue.main.async(execute: {
-                self.delegate?.fileproviderFailed(self, operation: opType)
-            })
+        } catch {
+            completionHandler?(error)
+            self.delegateNotify(operation, error: error)
            return nil
        }
-        
-        guard let r = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+        return progress
    }
    
    /**
@@ -505,12 +419,14 @@ open class CloudFileProvider: LocalFileProvider {
       - completionHandler: a closure with result of file contents or error.
         `contents`: contents of file in a `Data` object.
         `error`: Error returned by system.
-     - Returns: An `OperationHandle` to get progress or cancel progress.
+     - Returns: A `Progress` object to get progress or cancel progress.
     */
    @discardableResult
-    open override func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        guard let r = super.contents(path: path, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+    open override func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let progress = super.contents(path: path, completionHandler: completionHandler)
+        monitorFile(path: path, operation: operation, progress: progress)
+        return progress
    }
    
    /**
@@ -524,12 +440,14 @@ open class CloudFileProvider: LocalFileProvider {
       - completionHandler: a closure with result of file contents or error.
         `contents`: contents of file in a `Data` object.
         `error`: Error returned by system.
-     - Returns: An `OperationHandle` to get progress or cancel progress.
+     - Returns: A `Progress` object to get progress or cancel progress.
     */
    @discardableResult
-    open override func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        guard let r = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+    open override func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let progress = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler)
+        monitorFile(path: path, operation: operation, progress: progress)
+        return progress
    }
    
    /**
@@ -541,12 +459,19 @@ open class CloudFileProvider: LocalFileProvider {
       - overwrite: Destination file should be overwritten if file is already exists. Default is `false`.
       - atomically: data will be written to a temporary file before writing to final location. Default is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: A `Progress` object to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    open override func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard let r = super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
-        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
+    open override func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        monitorFile(path: path, operation: operation, progress: progress)
+        _ = super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler)
+        return progress
    }
    
    fileprivate var monitors = [String: (NSMetadataQuery, NSObjectProtocol)]()
@@ -611,13 +536,37 @@ open class CloudFileProvider: LocalFileProvider {
        return monitors[path] != nil
    }
    
-    open override func copy(with zone: NSZone? = nil) -> Any {
-        let copy = CloudFileProvider(containerId: self.containerId)
-        copy?.currentPath = self.currentPath
-        copy?.delegate = self.delegate
-        copy?.fileOperationDelegate = self.fileOperationDelegate
-        return copy as Any
+    fileprivate func updateQueryTypeKeys(_ queryComponent: NSPredicate) -> NSPredicate {
+        let mapDict: [String: String] = ["url": NSMetadataItemURLKey, "name": NSMetadataItemFSNameKey, "path": NSMetadataItemPathKey, "filesize": NSMetadataItemFSSizeKey, "modifiedDate": NSMetadataItemFSContentChangeDateKey, "creationDate": NSMetadataItemFSCreationDateKey, "contentType": NSMetadataItemContentTypeKey]
+        
+        if let cQuery = queryComponent as? NSCompoundPredicate {
+            let newSub = cQuery.subpredicates.map { updateQueryTypeKeys($0 as! NSPredicate) }
+            switch cQuery.compoundPredicateType {
+            case .and: return NSCompoundPredicate(andPredicateWithSubpredicates: newSub)
+            case .not: return NSCompoundPredicate(notPredicateWithSubpredicate: newSub.first!)
+            case .or:  return NSCompoundPredicate(orPredicateWithSubpredicates: newSub)
+            }
+        } else if let cQuery = queryComponent as? NSComparisonPredicate {
+            var newLeft = cQuery.leftExpression
+            var newRight = cQuery.rightExpression
+            if newLeft.expressionType == .keyPath, let newKey = mapDict[newLeft.keyPath] {
+                newLeft = NSExpression(forKeyPath: newKey)
+            }
+            if newRight.expressionType == .keyPath, let newKey = mapDict[newRight.keyPath] {
+                newRight = NSExpression(forKeyPath: newKey)
+            }
+            if newLeft.expressionType == .keyPath, newLeft.keyPath == "type" {
+                newRight = NSExpression(forConstantValue: newRight.constantValue as? String == "directory" ? "public.directory": "public.data")
+            }
+            if newRight.expressionType == .keyPath, newRight.keyPath == "type" {
+                newLeft = NSExpression(forConstantValue: newLeft.constantValue as? String == "directory" ? "public.directory": "public.data")
+            }
+            return NSComparisonPredicate(leftExpression: newLeft, rightExpression: newRight, modifier: cQuery.comparisonPredicateModifier, type: cQuery.predicateOperatorType, options: cQuery.options)
+        } else {
+            return queryComponent
+        }
    }
+
    
    fileprivate func mapFileObject(attributes attribs: [String: Any]) -> FileObject? {
        guard let url = (attribs[NSMetadataItemURLKey] as? URL)?.standardizedFileURL, let name = attribs[NSMetadataItemFSNameKey] as? String else {
@@ -625,8 +574,12 @@ open class CloudFileProvider: LocalFileProvider {
        }
        
        let path = self.relativePathOf(url: url)
+        #if swift(>=4.0)
+        let rpath = path.hasPrefix("/") ? String(path[path.index(after: path.startIndex)...]) : path
+        #else
        let rpath = path.hasPrefix("/") ? path.substring(from: path.index(after: path.startIndex)) : path
-        let relativeUrl = URL(string: rpath, relativeTo: self.baseURL)
+        #endif
+        let relativeUrl = URL(string: rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath, relativeTo: self.baseURL)
        let file = FileObject(url: relativeUrl ?? url, name: name, path: path)
        
        file.size = (attribs[NSMetadataItemFSSizeKey] as? NSNumber)?.int64Value ?? -1
@@ -639,33 +592,23 @@ open class CloudFileProvider: LocalFileProvider {
        return file
    }
    
-    /// Removes local copy of file, but spares cloud copy/
-    /// - Parameter path: Path of file or directory to be remoed from local
-    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-    open func evictItem(path: String, completionHandler: SimpleCompletionHandler) {
-        operation_queue.addOperation {
-            do {
-                try self.opFileManager.evictUbiquitousItem(at: self.url(of: path))
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
+    lazy fileprivate var observer: KVOObserver = KVOObserver()
+    
+    fileprivate func monitorFile(path: String, operation: FileOperationType, progress: Progress?) {
+        let pathURL = self.url(of: path).standardizedFileURL
+        let query = NSMetadataQuery()
+        query.predicate = NSPredicate(format: "%K LIKE[CD] %@", NSMetadataItemPathKey, pathURL.path)
+        query.valueListAttributes = [NSMetadataItemURLKey, NSMetadataItemFSNameKey, NSMetadataItemPathKey, NSMetadataUbiquitousItemPercentDownloadedKey, NSMetadataUbiquitousItemPercentUploadedKey, NSMetadataUbiquitousItemDownloadingStatusKey, NSMetadataItemFSSizeKey]
+        query.searchScopes = [self.scope.rawValue]
+        var context = QueryProgressWrapper(provider: self, progress: progress, operation: operation)
+        query.addObserver(self.observer, forKeyPath: "results", options: [.initial, .new, .old], context: &context)
+        
+        DispatchQueue.main.async {
+            query.start()
+            progress?.setUserInfoObject(Date(), forKey: .startingTimeKey)
        }
    }
    
-    /**
-     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
-     
-     - Important: URL will be available for a limitied time, determined in `expiration` argument.
-     
-     - Parameters:
-     - to: path of file, including file/directory name.
-     - completionHandler: a closure with result of directory entries or error.
-     `link`: a url returned by Dropbox to share.
-     `attribute`: a `FileObject` containing the attributes of the item.
-     `expiration`: a `Date` object, determines when the public url will expires.
-     `error`: Error returned by Dropbox.
-     */
    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
        operation_queue.addOperation {
            do {
@@ -674,22 +617,56 @@ open class CloudFileProvider: LocalFileProvider {
                self.dispatch_queue.async {
                    completionHandler(url, nil, expiration as Date?, nil)
                }
-            } catch let e {
+            } catch {
                self.dispatch_queue.async {
-                    completionHandler(nil, nil, nil, e)
+                    completionHandler(nil, nil, nil, error)
                }
            }
        }
    }
+    
+    /// Removes local copy of file, but spares cloud copy.
+    /// - Parameter path: Path of file or directory to be removed from local
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    open func evictItem(path: String, completionHandler: SimpleCompletionHandler) {
+        operation_queue.addOperation {
+            do {
+                try self.opFileManager.evictUbiquitousItem(at: self.url(of: path))
+                completionHandler?(nil)
+            } catch {
+                completionHandler?(error)
+            }
+        }
+    }
+    
+    /// Returns current version of file on this device and all versions of files in user devices.
+    /// - Parameter path: Path of file or directory.
+    /// - Parameter completionHandler: Retrieve current version on this device and all versions available. `currentVersion` will be nil if file doesn't exist. If an error parameter was provided, a presentable `Error` will be returned.
+    func versionsOfItem(path: String, completionHandler: @escaping ((_ currentVersion: NSFileVersion?, _ versions: [NSFileVersion], _ error: Error?) -> Void)) {
+        NotImplemented()
+    }
+    
+    /// Resolves conflicts by selecting a version.
+    /// - Parameter path: Path of file or directory.
+    /// - Parameter version: Version than will be choose as main version. `nil` value indicates current version on this device will be selected.
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    func selectVersionOfItem(path: String, version: NSFileVersion? = nil, completionHandler: SimpleCompletionHandler) {
+        NotImplemented()
+    }
 }

+/// Scope of iCloud, wrapper for NSMetadataQueryUbiquitous...Scope constants
 public enum UbiquitousScope: RawRepresentable {
    /// Search all files not in the Documents directories of the app’s iCloud container directories.
    /// Use this scope to store user-related data files that your app needs to share 
    /// but that are not files you want the user to manipulate directly.
+    ///
+    /// Raw value is equivalent to `NSMetadataQueryUbiquitousDataScope`
    case data
    /// Search all files in the Documents directories of the app’s iCloud container directories.
    /// Put documents that the user is allowed to access inside a Documents subdirectory.
+    ///
+    /// Raw value is equivalent to `NSMetadataQueryUbiquitousDocumentsScope`
    case documents
    
    public typealias RawValue = String
@@ -715,89 +692,86 @@ public enum UbiquitousScope: RawRepresentable {
    }
 }

-open class CloudOperationHandle: OperationHandle {
-    public let baseURL: URL?
-    public let operationType: FileOperationType
-    
-    init (operationType: FileOperationType, baseURL: URL?) {
-        self.baseURL = baseURL
-        self.operationType = operationType
-    }
-    
-    private var sourceURL: URL? {
-        guard let source = operationType.source, let baseURL = baseURL else { return nil }
-        return source.hasPrefix("file://") ? URL(fileURLWithPath: source) : baseURL.appendingPathComponent(source)
-    }
-    
-    private var destURL: URL? {
-        guard let dest = operationType.destination, let baseURL = baseURL else { return nil }
-        return dest.hasPrefix("file://") ? URL(fileURLWithPath: dest) : baseURL.appendingPathComponent(dest)
-    }
-    
-    open var bytesSoFar: Int64 {
-        assert(!Thread.isMainThread, "Don't run \(#function) method on main thread")
+struct QueryProgressWrapper {
+    weak var provider: CloudFileProvider?
+    weak var progress: Progress?
+    let operation: FileOperationType
+}
+
+fileprivate class KVOObserver: NSObject {
+    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
+        guard let query = object as? NSMetadataQuery else {
+            return
+        }
+        guard let wrapper = context?.load(as: QueryProgressWrapper.self) else {
+            query.stop()
+            query.removeObserver(self, forKeyPath: "results")
+            return
+        }
+        let provider = wrapper.provider
+        let progress = wrapper.progress
+        let operation = wrapper.operation
        
-        guard let url = destURL ?? sourceURL, let item = CloudOperationHandle.getMetadataItem(url: url) else { return 0 }
+        guard let results = change?[.newKey], let item = (results as? [NSMetadataItem])?.first else {
+            return
+        }
+        
+        query.disableUpdates()
+        var size = progress?.totalUnitCount ?? -1
+        if size < 0, let size_d = item.value(forAttribute: NSMetadataItemFSSizeKey) as? Int64 {
+            size = size_d
+            progress?.totalUnitCount = size
+        }
+        let downloadStatus = item.value(forAttribute: NSMetadataUbiquitousItemPercentDownloadedKey) as? String ?? ""
        let downloaded = item.value(forAttribute: NSMetadataUbiquitousItemPercentDownloadedKey) as? Double ?? 0
        let uploaded = item.value(forAttribute: NSMetadataUbiquitousItemPercentUploadedKey) as? Double ?? 0
-        guard let size = item.value(forAttribute: NSMetadataItemFSSizeKey) as? Int64 else { return -1 }
        if (downloaded == 0 || downloaded == 100) && (uploaded > 0 && uploaded < 100) {
-            return Int64(uploaded * (Double(size) / 100))
-        } else if (uploaded == 0 || uploaded == 100) && (downloaded > 0 && downloaded < 100) {
-            return Int64(downloaded * (Double(size) / 100))
-        } else if uploaded == 100 || downloaded == 100 {
-            return size
+            progress?.completedUnitCount = Int64(uploaded / 100 * Double(size))
+            provider?.delegateNotify(operation, progress: uploaded / 100)
+        } else if (uploaded == 0 || uploaded == 100) && downloadStatus != NSMetadataUbiquitousItemDownloadingStatusCurrent {
+            progress?.completedUnitCount = Int64(downloaded / 100 * Double(size))
+            provider?.delegateNotify(operation, progress: downloaded / 100)
+        } else if uploaded == 100 || downloadStatus == NSMetadataUbiquitousItemDownloadingStatusCurrent {
+            progress?.completedUnitCount = size
+            query.stop()
+            query.removeObserver(self, forKeyPath: "results")
+            provider?.delegateNotify(operation)
        }
-        return 0
-    }
-    
-    open var totalBytes: Int64 {
-        assert(!Thread.isMainThread, "Don't run \(#function) method on main thread")
-        guard let url = destURL ?? sourceURL, let item = CloudOperationHandle.getMetadataItem(url: url) else { return -1 }
-        return item.value(forAttribute: NSMetadataItemFSSizeKey) as? Int64 ?? -1
-    }
-    
-    open var inProgress: Bool {
-        guard let url = destURL ?? sourceURL, let item = CloudOperationHandle.getMetadataItem(url: url) else { return false }
-        let downloadStatus = item.value(forAttribute: NSMetadataUbiquitousItemDownloadingStatusKey) as? String ?? NSMetadataUbiquitousItemDownloadingStatusNotDownloaded
-        let isUploading = item.value(forAttribute: NSMetadataUbiquitousItemIsUploadingKey) as? Bool ?? false
-        return downloadStatus == NSMetadataUbiquitousItemDownloadingStatusCurrent || isUploading
-    }
-    
-    /// Not usable in local provider
-    open func cancel() -> Bool {
-        return false
-    }
-    
-    fileprivate static func getMetadataItem(url: URL) -> NSMetadataItem? {
-        let query = NSMetadataQuery()
-        query.predicate = NSPredicate(format: "(%K LIKE %@)", NSMetadataItemPathKey, url.path)
-        query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope, NSMetadataQueryUbiquitousDataScope]
        
-        var item: NSMetadataItem?
-        
-        let group = DispatchGroup()
-        group.enter()
-        var finishObserver: NSObjectProtocol?
-        finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
-            defer {
-                query.stop()
-                group.leave()
-                NotificationCenter.default.removeObserver(finishObserver!)
-            }
-            
-            if query.resultCount > 0 {
-                item = query.result(at: 0) as? NSMetadataItem
-            }
-            
-            query.disableUpdates()
-            
-        })
-        
-        DispatchQueue.main.async {
-            query.start()
-        }
-        _ = group.wait(timeout: .now() + 30)
-        return item
+        query.enableUpdates()
    }
 }
+
+/*
+func getMetadataItem(url: URL) -> NSMetadataItem? {
+    let query = NSMetadataQuery()
+    query.predicate = NSPredicate(format: "(%K LIKE %@)", NSMetadataItemPathKey, url.path)
+    query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope, NSMetadataQueryUbiquitousDataScope]
+    
+    var item: NSMetadataItem?
+    
+    let group = DispatchGroup()
+    group.enter()
+    var finishObserver: NSObjectProtocol?
+    finishObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
+        defer {
+            query.stop()
+            group.leave()
+            NotificationCenter.default.removeObserver(finishObserver!)
+        }
+        
+        if query.resultCount > 0 {
+            item = query.result(at: 0) as? NSMetadataItem
+        }
+        
+        query.disableUpdates()
+        
+    })
+    
+    DispatchQueue.main.async {
+        query.start()
+    }
+    _ = group.wait(timeout: .now() + 30)
+    return item
+}
+*/
@@ -14,109 +14,89 @@ import CoreGraphics
 Allows accessing to Dropbox stored files. This provider doesn't cache or save files internally, however you can
 set `useCache` and `cache` properties to use Foundation `NSURLCache` system.
 
+ - Note: You can pass file id or rev instead of file path, e.g `"id:1234abcd"` or `"rev:1234abcd"`, to point to a file or folder by ID.
+ 
 - Note: Uploading files and data are limited to 150MB, for now.
 */
-open class DropboxFileProvider: FileProviderBasicRemote {
-    open class var type: String { return "DropBox" }
-    open let baseURL: URL?
-    open var currentPath: String
+open class DropboxFileProvider: HTTPFileProvider, FileProviderSharing {
+    override open class var type: String { return "Dropbox" }
    
    /// Dropbox RPC API URL, which is equal with [https://api.dropboxapi.com/2/](https://api.dropboxapi.com/2/)
    open let apiURL: URL
    /// Dropbox contents download/upload API URL, which is equal with [https://content.dropboxapi.com/2/](https://content.dropboxapi.com/2/)
    open let contentURL: URL
    
-    open var dispatch_queue: DispatchQueue
-    open var operation_queue: OperationQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    
-    open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
-    open private(set) var cache: URLCache?
-    public var useCache: Bool
-    public var validatingCache: Bool
-   
-    fileprivate var _session: URLSession?
-    fileprivate var sessionDelegate: SessionDelegate?
-    public var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let config = URLSessionConfiguration.default
-            config.urlCache = cache
-            config.requestCachePolicy = .returnCacheDataElseLoad
-            _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
-        }
-        return _session!
-    }
-    
-    fileprivate var _longpollSession: URLSession?
-    internal var longpollSession: URLSession {
-        if _longpollSession == nil {
-            let config = URLSessionConfiguration.default
-            config.timeoutIntervalForRequest = 600
-            _longpollSession = URLSession(configuration: config, delegate: nil, delegateQueue: nil)
-        }
-        return _longpollSession!
-    }
-    
    /**
     Initializer for Dropbox provider with given client ID and Token.
     These parameters must be retrieved via [OAuth2 API of Dropbox](https://www.dropbox.com/developers/reference/oauth-guide).
     
-     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. 
-     The latter is easier to use and prefered. Also you can use [auth0/Lock](https://github.com/auth0/Lock.iOS-OSX) which provides graphical user interface.
+     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. The latter is easier to use and prefered.
     
     - Parameter credential: a `URLCredential` object with Client ID set as `user` and Token set as `password`.
     - Parameter cache: A URLCache to cache downloaded files and contents.
    */
    public init(credential: URLCredential?, cache: URLCache? = nil) {
-        self.baseURL = nil
-        self.currentPath = ""
-        self.useCache = false
-        self.validatingCache = true
-        self.cache = cache
-        self.credential = credential
-        
        self.apiURL = URL(string: "https://api.dropboxapi.com/2/")!
        self.contentURL = URL(string: "https://content.dropboxapi.com/2/")!
-        
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
-        operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
-
+        super.init(baseURL: nil, credential: credential, cache: cache)
    }
    
-    deinit {
-        if fileProviderCancelTasksOnInvalidating {
-            _session?.invalidateAndCancel()
-        } else {
-            _session?.finishTasksAndInvalidate()
-        }
+    public required convenience init?(coder aDecoder: NSCoder) {
+        self.init(credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.useCache        = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
    }
    
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
-        list(path) { (contents, cursor, error) in
-            completionHandler(contents, error)
-        }
+    override open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = DropboxFileProvider(credential: self.credential, cache: self.cache)
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        return copy
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameters:
+       - path: path to target directory. If empty, root will be iterated.
+       - completionHandler: a closure with result of directory entries or error.
+       - contents: An array of `FileObject` identifying the the directory entries.
+       - error: Error returned by system.
+     */
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
+        let query = NSPredicate(format: "TRUEPREDICATE")
+        _ = searchFiles(path: path, recursive: false, query: query, foundItemHandler: nil, completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameters:
+       - path: path to target directory. If empty, attributes of root will be returned.
+       - completionHandler: a closure with result of directory entries or error.
+       - attributes: A `FileObject` containing the attributes of the item.
+       - error: Error returned by system.
+     */
+    open override func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
        let url = URL(string: "files/get_metadata", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(httpContentType: .json)
        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
+            var serverError: FileProviderHTTPError?
            var fileObject: DropboxFileObject?
            if let response = response as? HTTPURLResponse {
                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code.flatMap { self.serverError(with: $0, path: path, data: data) }
                if let json = data?.deserializeJSON(), let file = DropboxFileObject(json: json) {
                    fileObject = file
                }
@@ -126,106 +106,151 @@ open class DropboxFileProvider: FileProviderBasicRemote {
        task.resume()
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+    /// Returns volume/provider information asynchronously.
+    /// - Parameter volumeInfo: Information of filesystem/Provider returned by system/server.
+    open override func storageProperties(completionHandler: @escaping (_ volumeInfo: VolumeObject?) -> Void) {
        let url = URL(string: "users/get_space_usage", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var totalSize: Int64 = -1
-            var usedSize: Int64 = 0
-            if let json = data?.deserializeJSON() {
-                totalSize = ((json["allocation"] as? NSDictionary)?["allocated"] as? NSNumber)?.int64Value ?? -1
-                usedSize = (json["used"] as? NSNumber)?.int64Value ?? 0
+            guard let json = data?.deserializeJSON() else {
+                completionHandler(nil)
+                return
            }
-            completionHandler(totalSize, usedSize)
+            
+            let volume = VolumeObject(allValues: [:])
+            volume.totalCapacity = ((json["allocation"] as? NSDictionary)?["allocated"] as? NSNumber)?.int64Value ?? -1
+            volume.usage = (json["used"] as? NSNumber)?.int64Value ?? 0
+            completionHandler(volume)
        }) 
        task.resume()
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
-        var foundFiles = [DropboxFileObject]()
-        if let queryStr = query.findValue(forKey: "name", operator: .beginsWith) as? String {
-            // Dropbox only support searching for file names begin with query in non-enterprise accounts.
-            // We will use it if there is a `name BEGINSWITH[c] "query"` in predicate, then filter to form final result.
-            search(path, query: queryStr, foundItem: { (file) in
-                if query.evaluate(with: file.mapPredicate()) {
-                    foundFiles.append(file)
-                    foundItemHandler?(file)
-                }
-            }, completionHandler: { (error) in
-                completionHandler(foundFiles, error)
-            })
+    /**
+     Search files inside directory using query asynchronously.
+     
+     Sample predicates:
+     ```
+     NSPredicate(format: "(name CONTAINS[c] 'hello') && (filesize >= 10000)")
+     NSPredicate(format: "(modifiedDate >= %@)", Date())
+     NSPredicate(format: "(path BEGINSWITH %@)", "folder/child folder")
+     ```
+     
+     - Note: Don't pass Spotlight predicates to this method directly, use `FileProvider.convertSpotlightPredicateTo()` method to get usable predicate.
+     
+     - Important: A file name criteria should be provided for Dropbox.
+     
+     - Parameters:
+       - path: location of directory to start search
+       - recursive: Searching subdirectories of path
+       - query: An `NSPredicate` object with keys like `FileObject` members, except `size` which becomes `filesize`.
+       - foundItemHandler: Closure which is called when a file is found
+       - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+       - files: all files meat the `query` criteria.
+       - error: `Error` returned by server if occured.
+     - Returns: An `Progress` to get progress or cancel progress. Use `completedUnitCount` to iterate count of found items.
+     */
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let queryStr: String?
+        if query.predicateFormat == "TRUEPREDICATE" {
+            queryStr = nil
        } else {
-            // Dropbox doesn't support searching attributes natively. The workaround is to fallback to listing all files
-            // and filter it locally. It may have a network burden in case there is many files in Dropbox, so please use it concisely.
-            list(path, recursive: true, progressHandler: { (files, _, error) in
-                for file in files where query.evaluate(with: file.mapPredicate()) {
+            queryStr = query.findValue(forKey: "name", operator: .beginsWith) as? String
+        }
+        let requestHandler = self.listRequest(path: path, queryStr: queryStr, recursive: recursive)
+        let queryIsTruePredicate = query.predicateFormat == "TRUEPREDICATE"
+        return paginated(path, requestHandler: requestHandler,
+            pageHandler: { [weak self] (data, progress) -> (files: [FileObject], error: Error?, newToken: String?) in
+            guard let json = data?.deserializeJSON(), let entries = (json["entries"] ?? json["matches"]) as? [AnyObject] else {
+                let err = self?.urlError(path, code: .badServerResponse)
+                return ([], err, nil)
+            }
+            
+            var files = [FileObject]()
+            for entry in entries {
+                if let entry = entry as? [String: AnyObject], let file = DropboxFileObject(json: entry), queryIsTruePredicate || query.evaluate(with: file.mapPredicate()) {
+                    files.append(file)
+                    progress.completedUnitCount += 1
                    foundItemHandler?(file)
                }
-            }, completionHandler: { (files, _, error) in
-                let predicatedFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
-                completionHandler(predicatedFiles, error)
-            })
+            }
+            let ncursor: String?
+            if let hasmore = (json["has_more"] as? NSNumber)?.boolValue, hasmore {
+                ncursor = json["cursor"] as? String
+            } else if let hasmore = (json["more"] as? NSNumber)?.boolValue, hasmore {
+                ncursor = (json["start"] as? Int).flatMap(String.init)
+            } else {
+                ncursor = nil
+            }
+            return (files, nil, ncursor)
+        }, completionHandler: completionHandler)
+    }
+    
+    override func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey : Any] = [:]) -> URLRequest {
+        
+        func uploadRequest(to path: String) -> URLRequest {
+            var requestDictionary = [String: AnyObject]()
+            let url: URL = URL(string: "files/upload", relativeTo: contentURL)!
+            requestDictionary["path"] = correctPath(path) as NSString?
+            requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
+            requestDictionary["client_modified"] = (attributes[.contentModificationDateKey] as? Date)?.format(with: .rfc3339) as NSString?
+            var request = URLRequest(url: url)
+            request.httpMethod = "POST"
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(httpContentType: .stream)
+            request.set(dropboxArgKey: requestDictionary)
+            return request
+        }
+        
+        func downloadRequest(from path: String) -> URLRequest {
+            let url = URL(string: "files/download", relativeTo: contentURL)!
+            var request = URLRequest(url: url)
+            request = URLRequest(url: url)
+            request.set(httpAuthentication: credential, with: .oAuth2)
+            request.set(dropboxArgKey: ["path": correctPath(path)! as NSString])
+            return request
+        }
+        
+        // content operations
+        switch operation {
+        case .copy(source: let source, destination: let dest) where dest.lowercased().hasPrefix("file://"):
+            return downloadRequest(from: source)
+        case .fetch(let path):
+            return downloadRequest(from: path)
+        case .copy(source: let source, destination: let dest) where source.lowercased().hasPrefix("file://"):
+            return uploadRequest(to: dest)
+        case .modify(let path):
+            return uploadRequest(to: path)
+        default:
+            return self.apiRequest(for: operation, overwrite: overwrite)
        }
    }
    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
-        self.storageProperties { total, _ in
-            completionHandler(total > 0)
-        }
-    }
-    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension DropboxFileProvider: FileProviderOperations {
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
-        return doOperation(.create(path: path), completionHandler: completionHandler)
-    }
-    
-    open func create(file fileName: String, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let filePath = (path as NSString).appendingPathComponent(fileName)
-        return self.writeContents(path: filePath, contents: data ?? Data(), completionHandler: completionHandler)
-    }
-    
-    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.remove(path: path), completionHandler: completionHandler)
-    }
-    
-    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
-            return nil
-        }
+    func apiRequest(for operation: FileOperationType, overwrite: Bool = false) -> URLRequest {
        let url: String
-        guard let sourcePath = operation.source else { return nil }
+        let sourcePath = operation.source
        let destPath = operation.destination
+        var requestDictionary = [String: AnyObject]()
        switch operation {
        case .create:
-            url = "files/create_folder"
+            url = "files/create_folder_v2"
+            
        case .copy:
-            url = "files/copy"
+            url = "files/copy_v2"
+            requestDictionary["allow_shared_folder"] = NSNumber(value: true)
        case .move:
-            url = "files/move"
+            url = "files/move_v2"
+            requestDictionary["allow_shared_folder"] = NSNumber(value: true)
        case .remove:
-            url = "files/delete"
+            url = "files/delete_v2"
        default: // modify, link, fetch
-            return nil
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
        }
        var request = URLRequest(url: URL(string: url, relativeTo: apiURL)!)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        var requestDictionary = [String: AnyObject]()
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(httpContentType: .json)
        if let dest = correctPath(destPath) as NSString? {
            requestDictionary["from_path"] = correctPath(sourcePath) as NSString?
            requestDictionary["to_path"] = dest
@@ -233,101 +258,21 @@ extension DropboxFileProvider: FileProviderOperations {
            requestDictionary["path"] = correctPath(sourcePath) as NSString?
        }
        request.httpBody = Data(jsonDictionary: requestDictionary)
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
-            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                 serverError = FileProviderDropboxError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(serverError ?? error)
-            self.delegateNotify(operation, error: serverError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
+        return request
    }
    
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        let errorDesc: String?
+        if let response = data?.deserializeJSON() {
+            errorDesc = (response["user_message"] as? String) ?? (response["error"]?["tag"] as? String)
+        } else {
+            errorDesc = data.flatMap({ String(data: $0, encoding: .utf8) })
        }
-        return upload_simple(toPath, localFile: localFile, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
+        return FileProviderDropboxError(code: code, path: path ?? "", errorDescription: errorDesc)
    }
    
-    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = URL(string: "files/download", relativeTo: contentURL)!
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let requestDictionary: [String: AnyObject] = ["path": path as NSString]
-        let requestJson = String(jsonDictionary: requestDictionary) ?? ""
-        request.setValue(requestJson, forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.downloadTask(with: request, completionHandler: { (cacheURL, response, error) in
-            guard let cacheURL = cacheURL, let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (response as? HTTPURLResponse)?.statusCode ?? -1)
-                let errorData : Data? = nil //Data(contentsOf:cacheURL) // TODO: Figure out how to get error response data for the error description
-                let serverError : FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                completionHandler?(serverError ?? error)
-                return
-            }
-            do {
-                try FileManager.default.moveItem(at: cacheURL, to: destURL)
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-}
-
-extension DropboxFileProvider: FileProviderReadWrite {
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 || offset < 0 {
-            dispatch_queue.async {
-                completionHandler(Data(), nil)
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.fetch(path: path)
-        let url = URL(string: "files/download", relativeTo: contentURL)!
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
-        }
-        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
-        request.setValue(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
-            if let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: httpResponse.statusCode) {
-                serverError = FileProviderDropboxError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            let filedata = serverError ?? error == nil ? data : nil
-            completionHandler(filedata, serverError ?? error)
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
-    public func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
+    override var maxUploadSimpleSupported: Int64 {
+        return 157_286_400 // 150MB
    }
    
    /*
@@ -345,53 +290,22 @@ extension DropboxFileProvider: FileProviderReadWrite {
    }
    */
    // TODO: Implement /get_account & /get_current_account
-}
-
-extension DropboxFileProvider {
-    /// *DEPRECATED:* Use `publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?))` function instead.
-    @available(*, deprecated, renamed: "publicLink(to:completionHandler:)", message: "Use publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
-    open func temporaryLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ error: Error?) -> Void)) {
-        self.publicLink(to: path) { (url, file, _, error) in
-            completionHandler(url, file, error)
-        }
-    }
    
-    /// *DEPRECATED:* Use `publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?))` function instead.
-    @available(*, deprecated, renamed: "publicLink(to:completionHandler:)", message: "Use publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
-    open func temporaryLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
-        self.publicLink(to: path) { (url, file, expiration, error) in
-            completionHandler(url, file, expiration, error)
-        }
-    }
-    
-    /**
-     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
-     
-     - Important: URL will be available for a limitied time (4 hours according to Dropbox documentation).
-     
-     - Parameters:
-       - to: path of file, including file/directory name.
-       - completionHandler: a closure with result of directory entries or error.
-         `link`: a url returned by Dropbox to share.
-         `attribute`: a `FileObject` containing the attributes of the item.
-         `expiration`: a `Date` object, determines when the public url will expires.
-         `error`: Error returned by Dropbox.
-    */
-    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
        let url = URL(string: "files/get_temporary_link", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(httpContentType: .json)
        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
+            var serverError: FileProviderHTTPError?
            var link: URL?
            var fileObject: DropboxFileObject?
            if let response = response as? HTTPURLResponse {
                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code.flatMap { self.serverError(with: $0, path: path, data: data) }
                if let json = data?.deserializeJSON() {
                    if let linkStr = json["link"] as? String {
                        link = URL(string: linkStr)
@@ -415,29 +329,29 @@ extension DropboxFileProvider {
       - remoteURL: a valid remote url to file.
       - to: Destination path of file, including file/directory name.
       - completionHandler: a closure with result of directory entries or error.
-         `jobId`: Job ID returned by Dropbox to monitor the copy/download progress.
-         `attribute`: A `FileObject` containing the attributes of the item.
-         `error`: Error returned by Dropbox.
+         - `jobId`: Job ID returned by Dropbox to monitor the copy/download progress.
+         - `attribute`: A `FileObject` containing the attributes of the item.
+         - `error`: Error returned by Dropbox.
     */
    open func copyItem(remoteURL: URL, to toPath: String, completionHandler: @escaping ((_ jobId: String?, _ attribute: DropboxFileObject?, _ error: Error?) -> Void)) {
        if remoteURL.isFileURL {
-            completionHandler(nil, nil, self.throwError(remoteURL.path, code: URLError.badURL))
+            completionHandler(nil, nil, self.urlError(remoteURL.path, code: .badURL))
            return
        }
        let url = URL(string: "files/save_url", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(httpContentType: .json)
        let requestDictionary: [String: AnyObject] = ["path": correctPath(toPath)! as NSString, "url" : remoteURL.absoluteString as NSString]
        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
+            var serverError: FileProviderHTTPError?
            var jobId: String?
            var fileObject: DropboxFileObject?
            if let response = response as? HTTPURLResponse {
                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code.flatMap { self.serverError(with: $0, path: toPath, data: data) }
                if let json = data?.deserializeJSON() {
                    jobId = json["async_job_id"] as? String
                    if let attribDic = json["metadata"] as? [String: AnyObject] {
@@ -462,15 +376,15 @@ extension DropboxFileProvider {
        let url = URL(string: "files/copy_reference/save", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(httpContentType: .json)
        let requestDictionary: [String: AnyObject] = ["path": correctPath(toPath)! as NSString, "copy_reference" : reference as NSString]
        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
+            var serverError: FileProviderHTTPError?
            if let response = response as? HTTPURLResponse {
                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code.flatMap { self.serverError(with: $0, path: toPath, data: data) }
            }
            completionHandler?(serverError ?? error)
        })
@@ -511,31 +425,42 @@ extension DropboxFileProvider: ExtendedFileProvider {
    /// Default value for dimension is 64x64, according to Dropbox documentation
    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
        let url: URL
+        let thumbAPI: Bool
        switch (path as NSString).pathExtension.lowercased() {
        case "jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff":
            url = URL(string: "files/get_thumbnail", relativeTo: contentURL)!
+            thumbAPI = true
        case "doc", "docx", "docm", "xls", "xlsx", "xlsm":
            fallthrough
        case  "ppt", "pps", "ppsx", "ppsm", "pptx", "pptm":
            fallthrough
        case "rtf":
            url = URL(string: "files/get_preview", relativeTo: contentURL)!
+            thumbAPI = false
        default:
            return
        }
        var request = URLRequest(url: url)
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
+        request.set(httpAuthentication: credential, with: .oAuth2)
        var requestDictionary: [String: AnyObject] = ["path": path as NSString]
-        requestDictionary["format"] = "jpeg" as NSString
-        if let dimension = dimension {
-            requestDictionary["size"] = "w\(Int(dimension.width))h\(Int(dimension.height))" as NSString
+        if thumbAPI {
+            requestDictionary["format"] = "jpeg" as NSString
+            let size: String
+            switch dimension?.height ?? 64 {
+            case 0...32:    size = "w32h32"
+            case 33...64:   size = "w64h64"
+            case 65...128:  size = "w128h128"
+            case 129...480: size = "w640h480"
+            default: size = "w1024h768"
+            }
+            requestDictionary["size"] = size as NSString
        }
-        request.setValue(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
+        request.set(dropboxArgKey: requestDictionary)
        let task = self.session.dataTask(with: request, completionHandler: { (data, response, error) in
            var image: ImageClass? = nil
            if let r = response as? HTTPURLResponse, let result = r.allHeaderFields["Dropbox-API-Result"] as? String, let jsonResult = result.deserializeJSON() {
                if jsonResult["error"] != nil {
-                    completionHandler(nil, self.throwError(path, code: URLError.cannotDecodeRawData as FoundationErrorEnum))
+                    completionHandler(nil, self.urlError(path, code: .cannotDecodeRawData))
                }
            }
            if let data = data {
@@ -543,8 +468,12 @@ extension DropboxFileProvider: ExtendedFileProvider {
                    image = pageImage
                } else if let contentType = (response as? HTTPURLResponse)?.allHeaderFields["Content-Type"] as? String, contentType.contains("text/html") {
                     // TODO: Implement converting html returned type of get_preview to image
-                } else {
-                    image = ImageClass(data: data)
+                } else if let fetchedimage = ImageClass(data: data){
+                    if let dimension = dimension {
+                        image = DropboxFileProvider.scaleDown(image: fetchedimage, toSize: dimension)
+                    } else {
+                        image = fetchedimage
+                    }
                }
            }
            completionHandler(image, error)
@@ -556,18 +485,18 @@ extension DropboxFileProvider: ExtendedFileProvider {
        let url = URL(string: "files/get_metadata", relativeTo: apiURL)!
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        request.set(httpContentType: .json)
        let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString, "include_media_info": NSNumber(value: true)]
        request.httpBody = Data(jsonDictionary: requestDictionary)
        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderDropboxError?
+            var serverError: FileProviderHTTPError?
            var dic = [String: Any]()
            var keys = [String]()
            if let response = response as? HTTPURLResponse {
                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
-                if let json = data?.deserializeJSON(), let properties = json["media_info"] as? [String: Any] {
+                serverError = code.flatMap { self.serverError(with: $0, path: path, data: data) }
+                if let json = data?.deserializeJSON(), let properties = (json["media_info"] as? [String: Any])?["metadata"] as? [String: Any] {
                    (dic, keys) = self.mapMediaInfo(properties)
                }
            }
@@ -576,15 +505,3 @@ extension DropboxFileProvider: ExtendedFileProvider {
        task.resume()
    }
 }
-
-extension DropboxFileProvider: FileProvider {
-    open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = DropboxFileProvider(credential: self.credential, cache: self.cache)
-        copy.currentPath = self.currentPath
-        copy.delegate = self.delegate
-        copy.fileOperationDelegate = self.fileOperationDelegate
-        copy.useCache = self.useCache
-        copy.validatingCache = self.validatingCache
-        return copy
-    }
-}
@@ -17,22 +17,22 @@ public struct FileProviderDropboxError: FileProviderHTTPError {

 /// Containts path, url and attributes of a Dropbox file or resource.
 public final class DropboxFileObject: FileObject {
-    internal init(name: String, path: String) {
-        super.init(url: URL(string: path) ?? URL(string: "/")!, name: name, path: path)
-    }
-    
    internal convenience init? (jsonStr: String) {
        guard let json = jsonStr.deserializeJSON() else { return nil }
        self.init(json: json)
    }
    
-    internal convenience init? (json: [String: AnyObject]) {
+    internal init? (json: [String: AnyObject]) {
+        var json = json
+        if json["name"] == nil, let metadata = json["metadata"] as? [String: AnyObject] {
+            json = metadata
+        }
        guard let name = json["name"] as? String else { return nil }
        guard let path = json["path_display"] as? String else { return nil }
-        self.init(name: name, path: path)
+        super.init(url: nil, name: name, path: path)
        self.size = (json["size"] as? NSNumber)?.int64Value ?? -1
-        self.serverTime = resolve(dateString: json["server_modified"] as? String ?? "")
-        self.modifiedDate = resolve(dateString: json["client_modified"] as? String ?? "")
+        self.serverTime =  (json["server_modified"] as? String).flatMap(Date.init(rfcString:))
+        self.modifiedDate = (json["client_modified"] as? String).flatMap(Date.init(rfcString:))
        self.type = (json[".tag"] as? String) == "folder" ? .directory : .regular
        self.isReadOnly = (json["sharing_info"]?["read_only"] as? NSNumber)?.boolValue ?? false
        self.id = json["id"] as? String
@@ -42,22 +42,21 @@ public final class DropboxFileObject: FileObject {
    /// The time contents of file has been modified on server, returns nil if not set
    open internal(set) var serverTime: Date? {
        get {
-            return allValues[.serverDate] as? Date
+            return allValues[.serverDateKey] as? Date
        }
        set {
-            allValues[.serverDate] = newValue
+            allValues[.serverDateKey] = newValue
        }
    }
    
    /// The document identifier is a value assigned by the Dropbox to a file.
    /// This value is used to identify the document regardless of where it is moved on a volume.
-    /// The identifier persists across system restarts.
    open internal(set) var id: String? {
        get {
-            return allValues[.documentIdentifierKey] as? String
+            return allValues[.fileResourceIdentifierKey] as? String
        }
        set {
-            allValues[.documentIdentifierKey] = newValue
+            allValues[.fileResourceIdentifierKey] = newValue
        }
    }
    
@@ -73,157 +72,57 @@ public final class DropboxFileObject: FileObject {
    }
 }

-// codebeat:disable[ARITY]
 internal extension DropboxFileProvider {
-    func list(_ path: String, cursor: String? = nil, prevContents: [DropboxFileObject] = [], recursive: Bool = false, session: URLSession? = nil, progressHandler: ((_ contents: [FileObject], _ nextCursor: String?, _ error: Error?) -> Void)? = nil, completionHandler: @escaping ((_ contents: [FileObject], _ cursor: String?, _ error: Error?) -> Void)) {
-        var requestDictionary = [String: AnyObject]()
-        let url: URL
-        if let cursor = cursor {
-            url = URL(string: "files/list_folder/continue", relativeTo: apiURL)!
-            requestDictionary["cursor"] = cursor as NSString?
+    internal func correctPath(_ path: String?) -> String? {
+        guard let path = path else { return nil }
+        if path.hasPrefix("id:") || path.hasPrefix("rev:") {
+            return path
+        }
+        var p = path.hasPrefix("/") ? path : "/" + path
+        if p.hasSuffix("/") {
+            p.remove(at: p.index(before:p.endIndex))
+        }
+        return p
+    }
+    
+    internal func listRequest(path: String, queryStr: String? = nil, recursive: Bool = false) -> ((_ token: String?) -> URLRequest?) {
+        if let queryStr = queryStr {
+            return { [weak self] (token) -> URLRequest? in
+                guard let `self` = self else { return nil }
+                let url = URL(string: "files/search", relativeTo: self.apiURL)!
+                var request = URLRequest(url: url)
+                request.httpMethod = "POST"
+                request.set(httpAuthentication: self.credential, with: .oAuth2)
+                request.set(httpContentType: .json)
+                var requestDictionary: [String: AnyObject] = ["path": self.correctPath(path) as NSString!]
+                requestDictionary["query"] = queryStr as NSString
+                requestDictionary["start"] = NSNumber(value: (token.flatMap( { Int($0) } ) ?? 0))
+                request.httpBody = Data(jsonDictionary: requestDictionary)
+                return request
+            }
        } else {
-            url = URL(string: "files/list_folder", relativeTo: apiURL)!
-            requestDictionary["path"] = correctPath(path) as NSString?
-            requestDictionary["recursive"] = recursive as NSNumber?
-        }
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        request.httpBody = Data(jsonDictionary: requestDictionary)
-        let task = (session ?? self.session).dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderDropboxError?
-            var files = [DropboxFileObject]()
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderDropboxError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            if let json = data?.deserializeJSON() {
-                if let entries = json["entries"] as? [AnyObject] , entries.count > 0 {
-                    files.reserveCapacity(entries.count)
-                    for entry in entries {
-                        if let entry = entry as? [String: AnyObject], let file = DropboxFileObject(json: entry) {
-                            files.append(file)
-                        }
-                    }
-                    let ncursor = json["cursor"] as? String
-                    let hasmore = (json["has_more"] as? NSNumber)?.boolValue ?? false
-                    if hasmore {
-                        progressHandler?(files, ncursor, responseError ?? error)
-                        self.list(path, cursor: ncursor, prevContents: prevContents + files, completionHandler: completionHandler)
-                        return
-                    }
+            return { [weak self] (token) -> URLRequest? in
+                guard let `self` = self else { return nil }
+                var requestDictionary = [String: AnyObject]()
+                let url: URL
+                if let token = token {
+                    url = URL(string: "files/list_folder/continue", relativeTo: self.apiURL)!
+                    requestDictionary["cursor"] = token as NSString?
+                } else {
+                    url = URL(string: "files/list_folder", relativeTo: self.apiURL)!
+                    requestDictionary["path"] = self.correctPath(path) as NSString?
+                    requestDictionary["recursive"] = NSNumber(value: recursive)
                }
+                var request = URLRequest(url: url)
+                request.httpMethod = "POST"
+                request.set(httpAuthentication: self.credential, with: .oAuth2)
+                request.set(httpContentType: .json)
+                request.httpBody = Data(jsonDictionary: requestDictionary)
+                return request
            }
-            progressHandler?(files, nil, responseError ?? error)
-            completionHandler(prevContents + files, nil, responseError ?? error)
-        })
-        task.taskDescription = FileOperationType.fetch(path: path).json
-        task.resume()
-    }
-    
-    func upload_simple(_ targetPath: String, data: Data, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        if data.count > 150 * 1024 * 1024 {
-            let error = FileProviderDropboxError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
        }
-        var requestDictionary = [String: AnyObject]()
-        let url: URL
-        url = URL(string: "files/upload", relativeTo: contentURL)!
-        requestDictionary["path"] = correctPath(targetPath) as NSString?
-        requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
-        requestDictionary["client_modified"] = rfc3339utc(of: modifiedDate) as NSString
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        request.setValue(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        request.httpBody = data
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderDropboxError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderDropboxError(code: rCode, path: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(.create(path: targetPath), error: responseError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    func upload_simple(_ targetPath: String, localFile: URL, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let size = (try? localFile.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1
-        if size > 150 * 1024 * 1024 {
-            let error = FileProviderDropboxError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        var requestDictionary = [String: AnyObject]()
-        let url: URL
-        url = URL(string: "files/upload", relativeTo: contentURL)!
-        requestDictionary["path"] = correctPath(targetPath) as NSString?
-        requestDictionary["mode"] = (overwrite ? "overwrite" : "add") as NSString
-        requestDictionary["client_modified"] = rfc3339utc(of: modifiedDate) as NSString
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        request.setValue(String(jsonDictionary: requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
-            var responseError: FileProviderDropboxError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderDropboxError(code: rCode, path: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(.create(path: targetPath), error: responseError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    func search(_ startPath: String = "", query: String, start: Int = 0, maxResultPerPage: Int = 25, maxResults: Int = -1, foundItem:@escaping ((_ file: DropboxFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
-        let url = URL(string: "files/search", relativeTo: apiURL)!
-        var request = URLRequest(url: url)
-        request.httpMethod = "POST"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        var requestDictionary: [String: AnyObject] = ["path": startPath as NSString]
-        requestDictionary["query"] = query as NSString
-        requestDictionary["start"] = start as NSNumber
-        requestDictionary["max_results"] = maxResultPerPage as NSNumber
-        request.httpBody = Data(jsonDictionary: requestDictionary)
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderDropboxError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderDropboxError(code: rCode, path: startPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            if let json = data?.deserializeJSON() {
-                if let entries = json["matches"] as? [AnyObject] , entries.count > 0 {
-                    for entry in entries {
-                        if let entry = entry as? [String: AnyObject], let file = DropboxFileObject(json: entry) {
-                            foundItem(file)
-                        }
-                    }
-                    let rstart = json["start"] as? Int
-                    let hasmore = (json["more"] as? NSNumber)?.boolValue ?? false
-                    if hasmore, let rstart = rstart {
-                        self.search(startPath, query: query, start: rstart + entries.count, maxResultPerPage: maxResultPerPage, foundItem: foundItem, completionHandler: completionHandler)
-                    } else {
-                        completionHandler(responseError ?? error)
-                    }
-                    return
-                }
-            }
-            completionHandler(responseError ?? error)
-        }) 
-        task.resume()
    }
 }
-// codebeat:enable[ARITY]

 internal extension DropboxFileProvider {
    static let dateFormatter = DateFormatter()
@@ -241,11 +140,11 @@ internal extension DropboxFileProvider {
            DropboxFileProvider.decimalFormatter.numberStyle = .decimal
            DropboxFileProvider.decimalFormatter.maximumFractionDigits = 5
            keys.append("Location")
-            let latStr = DropboxFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))
-            let longStr = DropboxFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))
+            let latStr = DropboxFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))!
+            let longStr = DropboxFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))!
            dic["Location"] = "\(latStr), \(longStr)"
        }
-        if let timeTakenStr = json["time_taken"] as? String, let timeTaken = resolve(dateString: timeTakenStr) {
+        if let timeTakenStr = json["time_taken"] as? String, let timeTaken = Date(rfcString: timeTakenStr) {
            keys.append("Date taken")
            DropboxFileProvider.dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
            dic["Date taken"] = DropboxFileProvider.dateFormatter.string(from: timeTaken)
@@ -256,14 +155,4 @@ internal extension DropboxFileProvider {
        }
        return (dic, keys)
    }
-    
-    func delegateNotify(_ operation: FileOperationType, error: Error?) {
-        DispatchQueue.main.async(execute: {
-            if error == nil {
-                self.delegate?.fileproviderSucceed(self, operation: operation)
-            } else {
-                self.delegate?.fileproviderFailed(self, operation: operation)
-            }
-        })
-    }
 }
@@ -12,41 +12,41 @@ import CoreGraphics
 import AVFoundation

 extension LocalFileProvider: ExtendedFileProvider {
-    public func thumbnailOfFileSupported(path: String) -> Bool {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
        switch (path as NSString).pathExtension.lowercased() {
-        case LocalFileInformationGenerator.imageThumbnailExtensions:
+        case LocalFileInformationGenerator.imageThumbnailExtensions.contains:
            return true
-        case LocalFileInformationGenerator.audioThumbnailExtensions:
+        case LocalFileInformationGenerator.audioThumbnailExtensions.contains:
            return true
-        case LocalFileInformationGenerator.videoThumbnailExtensions:
+        case LocalFileInformationGenerator.videoThumbnailExtensions.contains:
            return true
-        case LocalFileInformationGenerator.pdfThumbnailExtensions:
+        case LocalFileInformationGenerator.pdfThumbnailExtensions.contains:
            return true
-        case LocalFileInformationGenerator.officeThumbnailExtensions:
+        case LocalFileInformationGenerator.officeThumbnailExtensions.contains:
            return true
-        case LocalFileInformationGenerator.customThumbnailExtensions:
+        case LocalFileInformationGenerator.customThumbnailExtensions.contains:
            return true
        default:
            return false
        }
    }
    
-    public func propertiesOfFileSupported(path: String) -> Bool {
+    open func propertiesOfFileSupported(path: String) -> Bool {
        let fileExt = (path as NSString).pathExtension.lowercased()
        switch fileExt {
-        case LocalFileInformationGenerator.imagePropertiesExtensions:
+        case LocalFileInformationGenerator.imagePropertiesExtensions.contains:
            return LocalFileInformationGenerator.imageProperties != nil
-        case LocalFileInformationGenerator.audioPropertiesExtensions:
+        case LocalFileInformationGenerator.audioPropertiesExtensions.contains:
            return LocalFileInformationGenerator.audioProperties != nil
-        case LocalFileInformationGenerator.videoPropertiesExtensions:
+        case LocalFileInformationGenerator.videoPropertiesExtensions.contains:
            return LocalFileInformationGenerator.videoProperties != nil
-        case LocalFileInformationGenerator.pdfPropertiesExtensions:
+        case LocalFileInformationGenerator.pdfPropertiesExtensions.contains:
            return LocalFileInformationGenerator.pdfProperties != nil
-        case LocalFileInformationGenerator.archivePropertiesExtensions:
+        case LocalFileInformationGenerator.archivePropertiesExtensions.contains:
            return LocalFileInformationGenerator.archiveProperties != nil
-        case LocalFileInformationGenerator.officePropertiesExtensions:
+        case LocalFileInformationGenerator.officePropertiesExtensions.contains:
            return LocalFileInformationGenerator.officeProperties != nil
-        case LocalFileInformationGenerator.customPropertiesExtensions:
+        case LocalFileInformationGenerator.customPropertiesExtensions.contains:
            return LocalFileInformationGenerator.customProperties != nil

        default:
@@ -54,7 +54,7 @@ extension LocalFileProvider: ExtendedFileProvider {
        }
    }
    
-    public func thumbnailOfFile(path: String, dimension: CGSize? = nil, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+    open func thumbnailOfFile(path: String, dimension: CGSize? = nil, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
        let dimension = dimension ?? CGSize(width: 64, height: 64)
        (dispatch_queue).async {
            var thumbnailImage: ImageClass? = nil
@@ -62,17 +62,17 @@ extension LocalFileProvider: ExtendedFileProvider {
            let fileURL = self.url(of: path)
            // Create Thumbnail and cache
            switch fileURL.pathExtension.lowercased() {
-            case LocalFileInformationGenerator.videoThumbnailExtensions:
+            case LocalFileInformationGenerator.videoThumbnailExtensions.contains:
                thumbnailImage = LocalFileInformationGenerator.videoThumbnail(fileURL)
-            case LocalFileInformationGenerator.audioThumbnailExtensions:
+            case LocalFileInformationGenerator.audioThumbnailExtensions.contains:
                thumbnailImage = LocalFileInformationGenerator.audioThumbnail(fileURL)
-            case LocalFileInformationGenerator.imageThumbnailExtensions:
+            case LocalFileInformationGenerator.imageThumbnailExtensions.contains:
                thumbnailImage = LocalFileInformationGenerator.imageThumbnail(fileURL)
-            case LocalFileInformationGenerator.pdfThumbnailExtensions:
+            case LocalFileInformationGenerator.pdfThumbnailExtensions.contains:
                thumbnailImage = LocalFileInformationGenerator.pdfThumbnail(fileURL)
-            case LocalFileInformationGenerator.officeThumbnailExtensions:
+            case LocalFileInformationGenerator.officeThumbnailExtensions.contains:
                thumbnailImage = LocalFileInformationGenerator.officeThumbnail(fileURL)
-            case LocalFileInformationGenerator.customThumbnailExtensions:
+            case LocalFileInformationGenerator.customThumbnailExtensions.contains:
                thumbnailImage = LocalFileInformationGenerator.customThumbnail(fileURL)
            default:
                completionHandler(nil, nil)
@@ -86,24 +86,24 @@ extension LocalFileProvider: ExtendedFileProvider {
        }
    }
    
-    public func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void)) {
+    open func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void)) {
        (dispatch_queue).async {
            let fileExt = (path as NSString).pathExtension.lowercased()
            var getter: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))?
            switch fileExt {
-            case LocalFileInformationGenerator.imagePropertiesExtensions:
+            case LocalFileInformationGenerator.imagePropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.imageProperties
-             case LocalFileInformationGenerator.audioPropertiesExtensions:
+             case LocalFileInformationGenerator.audioPropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.audioProperties
-            case LocalFileInformationGenerator.videoPropertiesExtensions:
+            case LocalFileInformationGenerator.videoPropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.videoProperties
-            case LocalFileInformationGenerator.pdfPropertiesExtensions:
+            case LocalFileInformationGenerator.pdfPropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.pdfProperties
-            case LocalFileInformationGenerator.archivePropertiesExtensions:
+            case LocalFileInformationGenerator.archivePropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.archiveProperties
-            case LocalFileInformationGenerator.officePropertiesExtensions:
+            case LocalFileInformationGenerator.officePropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.officeProperties
-            case LocalFileInformationGenerator.customPropertiesExtensions:
+            case LocalFileInformationGenerator.customPropertiesExtensions.contains:
                getter = LocalFileInformationGenerator.customProperties
            default:
                break
@@ -125,18 +125,18 @@ public struct LocalFileInformationGenerator {
    /// Image extensions supportes for thumbnail.
    ///
    /// Default: `["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]`
-    static public var imageThumbnailExtensions: [String]  = ["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]
+    static public var imageThumbnailExtensions: [String]  = ["heic", "jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]
    
    /// Audio and music extensions supportes for thumbnail.
    ///
-    /// Default: `["mp3", "aac", "m4a"]`
-    static public var audioThumbnailExtensions: [String]  = ["mp3", "aac", "m4a"]
+    /// Default: `["mp1", "mp2", "mp3", "mpa", "mpga", "m1a", "m2a", "m4a", "m4b", "m4p", "m4r", "aac", "snd", "caf", "aa", "aax", "adts", "aif", "aifc", "aiff", "au", "flac", "amr", "wav", "wave", "bwf", "ac3", "eac3", "ec3", "cdda"]`
+    static public var audioThumbnailExtensions: [String]  = ["mp1", "mp2", "mp3", "mpa", "mpga", "m1a", "m2a", "m4a", "m4b", "m4p", "m4r", "aac", "snd", "caf", "aa", "aax", "adts", "aif", "aifc", "aiff", "au", "flac", "amr", "wav", "wave", "bwf", "ac3", "eac3", "ec3", "cdda"]
    
    /// Video extensions supportes for thumbnail.
    ///
-    /// Default: `["mov", "mp4", "m4v", "mpg", "mpeg"]`
-    static public var videoThumbnailExtensions: [String]  = ["mov", "mp4", "m4v", "mpg", "mpeg"]
-    
+    /// Default: `["mov", "mp4", "mpg4", "m4v", "mqv", "mpg", "mpeg", "avi", "vfw", "3g2", "3gp", "3gp2", "3gpp", "qt"]`
+    static public var videoThumbnailExtensions: [String]  = ["mov", "mp4", "mpg4", "m4v", "mqv", "mpg", "mpeg", "avi", "vfw", "3g2", "3gp", "3gp2", "3gpp", "qt"]
+
    /// Portable document file extensions supportes for thumbnail.
    ///
    /// Default: `["pdf"]`
@@ -156,17 +156,17 @@ public struct LocalFileInformationGenerator {
    /// Image extensions supportes for properties.
    ///
    /// Default: `["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff"]`
-    static public var imagePropertiesExtensions: [String]   = ["jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff"]
+    static public var imagePropertiesExtensions: [String]   = ["heic", "jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff"]
    
    /// Audio and music extensions supportes for properties.
    ///
-    /// Default: `["mp3", "aac", "m4a", "caf"]`
-    static public var audioPropertiesExtensions: [String]   = ["mp3", "aac", "m4a", "caf"]
+    /// Default: `["mp1", "mp2", "mp3", "mpa", "mpga", "m1a", "m2a", "m4a", "m4b", "m4p", "m4r", "aac", "snd", "caf", "aa", "aax", "adts", "aif", "aifc", "aiff", "au", "flac", "amr", "wav", "wave", "bwf", "ac3", "eac3", "ec3", "cdda"]`
+    static public var audioPropertiesExtensions: [String]   = ["mp1", "mp2", "mp3", "mpa", "mpga", "m1a", "m2a", "m4a", "m4b", "m4p", "m4r", "aac", "snd", "caf", "aa", "aax", "adts", "aif", "aifc", "aiff", "au", "flac", "amr", "wav", "wave", "bwf", "ac3", "eac3", "ec3", "cdda"]
    
    /// Video extensions supportes for properties.
    ///
-    /// Default: `["mp4", "mpg", "3gp", "mov", "avi"]`
-    static public var videoPropertiesExtensions: [String]   = ["mp4", "mpg", "3gp", "mov", "avi"]
+    /// Default: `["mov", "mp4", "mpg4", "m4v", "mqv", "mpg", "mpeg", "avi", "vfw", "3g2", "3gp", "3gp2", "3gpp", "qt"]`
+    static public var videoPropertiesExtensions: [String]   = ["mov", "mp4", "mpg4", "m4v", "mqv", "mpg", "mpeg", "avi", "vfw", "3g2", "3gp", "3gp2", "3gpp", "qt"]
    
    /// Portable document file extensions supportes for properties.
    ///
@@ -197,8 +197,13 @@ public struct LocalFileInformationGenerator {
    static public var audioThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
        let playerItem = AVPlayerItem(url: fileURL)
        let metadataList = playerItem.asset.commonMetadata
+        #if swift(>=4.0)
+        let commonKeyArtwork = AVMetadataKey.commonKeyArtwork
+        #else
+        let commonKeyArtwork = AVMetadataCommonKeyArtwork
+        #endif
        for item in metadataList {
-            if item.commonKey == AVMetadataCommonKeyArtwork {
+            if item.commonKey == commonKeyArtwork {
                if let data = item.dataValue {
                    return ImageClass(data: data)
                }
@@ -319,28 +324,34 @@ public struct LocalFileInformationGenerator {
            guard let key = key else {
                return nil
            }
-            guard let regex = try? NSRegularExpression(pattern: "([a-z])([A-Z])" , options: NSRegularExpression.Options()) else {
+            guard let regex = try? NSRegularExpression(pattern: "([a-z])([A-Z])" , options: []) else {
                return nil
            }
-            let newKey = regex.stringByReplacingMatches(in: key, options: NSRegularExpression.MatchingOptions(), range: NSMakeRange(0, (key as NSString).length) , withTemplate: "$1 $2")
+            let newKey = regex.stringByReplacingMatches(in: key, options: [], range: NSRange(location: 0, length: (key as NSString).length) , withTemplate: "$1 $2")
            return newKey.capitalized
        }
        
-        if FileManager.default.fileExists(atPath: fileURL.path) {
-            let playerItem = AVPlayerItem(url: fileURL)
-            let metadataList = playerItem.asset.commonMetadata
-            for item in metadataList {
-                if let description = makeDescription(item.commonKey) {
-                    if let value = item.stringValue {
-                        keys.append(description)
-                        dic[description] = value
-                    }
+        guard FileManager.default.fileExists(atPath: fileURL.path) else {
+            return (dic, keys)
+        }
+        let playerItem = AVPlayerItem(url: fileURL)
+        let metadataList = playerItem.asset.commonMetadata
+        for item in metadataList {
+            #if swift(>=4.0)
+                let commonKey = item.commonKey?.rawValue
+            #else
+                let commonKey = item.commonKey
+            #endif
+            if let description = makeDescription(commonKey) {
+                if let value = item.stringValue {
+                    keys.append(description)
+                    dic[description] = value
                }
            }
-            if let ap = try? AVAudioPlayer(contentsOf: fileURL) {
-                add(key: "Duration", value: ap.duration.formatshort)
-                add(key: "Bitrate", value: ap.settings[AVSampleRateKey] as? Int)
-            }
+        }
+        if let ap = try? AVAudioPlayer(contentsOf: fileURL) {
+            add(key: "Duration", value: ap.duration.formatshort)
+            add(key: "Bitrate", value: ap.settings[AVSampleRateKey] as? Int)
        }
        return (dic, keys)
    }
@@ -366,7 +377,11 @@ public struct LocalFileInformationGenerator {
            }
        }
        let asset = AVURLAsset(url: fileURL, options: nil)
+        #if swift(>=4.0)
+        let videoTracks = asset.tracks(withMediaType: AVMediaType.video)
+        #else
        let videoTracks = asset.tracks(withMediaType: AVMediaTypeVideo)
+        #endif
        if let videoTrack = videoTracks.first {
            var bitrate: Float = 0
            let width = Int(videoTrack.naturalSize.width)
@@ -380,7 +395,11 @@ public struct LocalFileInformationGenerator {
            add(key: "Duration", value: TimeInterval(duration).formatshort)
            add(key: "Video Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
        }
+        #if swift(>=4.0)
+        let audioTracks = asset.tracks(withMediaType: AVMediaType.audio)
+        #else
        let audioTracks = asset.tracks(withMediaType: AVMediaTypeAudio)
+        #endif
        // dic["Audio channels"] = audioTracks.count
        var bitrate: Float = 0
        for track in audioTracks {
@@ -403,21 +422,37 @@ public struct LocalFileInformationGenerator {
        }
        
        func getKey(_ key: String, from dict: CGPDFDictionaryRef) -> String? {
-            var cfValue: CGPDFStringRef? = nil
-            if (CGPDFDictionaryGetString(dict, key, &cfValue)), let value = CGPDFStringCopyTextString(cfValue!) {
+            var cfStrValue: CGPDFStringRef?
+            if (CGPDFDictionaryGetString(dict, key, &cfStrValue)), let value = cfStrValue.flatMap({ CGPDFStringCopyTextString($0) }) {
                return value as String
            }
+            var cfArrayValue: CGPDFArrayRef?
+            if (CGPDFDictionaryGetArray(dict, key, &cfArrayValue)), let cfArray = cfArrayValue {
+                var array = [String]()
+                for i in 0..<CGPDFArrayGetCount(cfArray) {
+                    var cfItemValue: CGPDFStringRef?
+                    if CGPDFArrayGetString(cfArray, i, &cfItemValue), let item = cfItemValue.flatMap({ CGPDFStringCopyTextString($0) }) {
+                        array.append(item as String)
+                    }
+                }
+                return array.joined(separator: ", ")
+            }
            return nil
        }
        
        func convertDate(_ date: String?) -> Date? {
            guard let date = date else { return nil }
-            var dateStr = date
-            if dateStr.hasPrefix("D:") {
-                dateStr = date.substring(from: date.characters.index(date.startIndex, offsetBy: 2))
-            }
+            let dateStr = date.replacingOccurrences(of: "'", with: "").replacingOccurrences(of: "D:", with: "", options: .anchored)
            let dateFormatter = DateFormatter()
-            dateFormatter.dateFormat = "yyyyMMddHHmmssTZD"
+            dateFormatter.dateFormat = "yyyyMMddHHmmssTZ"
+            if let result = dateFormatter.date(from: dateStr) {
+                return result
+            }
+            dateFormatter.dateFormat = "yyyyMMddHHmmssZZZZZ"
+            if let result = dateFormatter.date(from: dateStr) {
+                return result
+            }
+            dateFormatter.dateFormat = "yyyyMMddHHmmssZ"
            if let result = dateFormatter.date(from: dateStr) {
                return result
            }
@@ -428,29 +463,32 @@ public struct LocalFileInformationGenerator {
            return nil
        }
        
-        if let provider = CGDataProvider(url: fileURL as CFURL), let reference = CGPDFDocument(provider), let dict = reference.info {
-            add(key: "Title", value: getKey("Title", from: dict))
-            add(key: "Author", value: getKey("Author", from: dict))
-            add(key: "Subject", value: getKey("Subject", from: dict))
-            var majorVersion: Int32 = 0
-            var minorVersion: Int32 = 0
-            reference.getVersion(majorVersion: &majorVersion, minorVersion: &minorVersion)
-            if majorVersion > 0 {
-                add(key: "Version", value:  String(majorVersion) + "." + String(minorVersion))
-            }
-            add(key: "Pages", value: reference.numberOfPages)
-            
-            if reference.numberOfPages > 0, let pageRef = reference.page(at: 1) {
-                let size = pageRef.getBoxRect(CGPDFBox.mediaBox).size
-                add(key: "Resolution", value: "\(Int(size.width))x\(Int(size.height))")
-            }
-            add(key: "Content creator", value: getKey("Creator", from: dict))
-            add(key: "Creation date", value: convertDate(getKey("CreationDate", from: dict)))
-            add(key: "Modified date", value: convertDate(getKey("ModDate", from: dict)))
-            add(key: "Security", value: reference.isEncrypted ? "Present" : "None")
-            add(key: "Allows printing", value: reference.allowsPrinting ? "Yes" : "No")
-            add(key: "Allows copying", value: reference.allowsCopying ? "Yes" : "No")
+        guard let provider = CGDataProvider(url: fileURL as CFURL), let reference = CGPDFDocument(provider), let dict = reference.info else {
+            return (dic, keys)
        }
+        add(key: "Title", value: getKey("Title", from: dict))
+        add(key: "Author", value: getKey("Author", from: dict))
+        add(key: "Subject", value: getKey("Subject", from: dict))
+        add(key: "Producer", value: getKey("Producer", from: dict))
+        add(key: "Keywords", value: getKey("Keywords", from: dict))
+        var majorVersion: Int32 = 0
+        var minorVersion: Int32 = 0
+        reference.getVersion(majorVersion: &majorVersion, minorVersion: &minorVersion)
+        if majorVersion > 0 {
+            add(key: "Version", value:  String(majorVersion) + "." + String(minorVersion))
+        }
+        add(key: "Pages", value: reference.numberOfPages)
+        
+        if reference.numberOfPages > 0, let pageRef = reference.page(at: 1) {
+            let size = pageRef.getBoxRect(CGPDFBox.mediaBox).size
+            add(key: "Resolution", value: "\(Int(size.width))x\(Int(size.height))")
+        }
+        add(key: "Content creator", value: getKey("Creator", from: dict))
+        add(key: "Creation date", value: convertDate(getKey("CreationDate", from: dict)))
+        add(key: "Modified date", value: convertDate(getKey("ModDate", from: dict)))
+        add(key: "Security", value: reference.isEncrypted)
+        add(key: "Allows printing", value: reference.allowsPrinting)
+        add(key: "Allows copying", value: reference.allowsCopying)
        return (dic, keys)
    }
    
@@ -466,7 +504,3 @@ public struct LocalFileInformationGenerator {
    /// - Note: No default implementation is avaiable
    static public var customProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = nil
 }
-
-fileprivate func ~=<T : Equatable>(array: [T], value: T) -> Bool {
-    return array.contains(value)
-}
@@ -0,0 +1,502 @@
+//
+//  FileProviderExtensions.swift
+//  FileProvider
+//
+//  Created by Amir Abbas on 12/27/1395 AP.
+//
+//
+
+import Foundation
+
+public extension Array where Element: FileObject {
+    /// Returns a sorted array of `FileObject`s by criterias set in attributes.
+    public func sort(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) -> [Element] {
+        let sorting = FileObjectSorting(type: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
+        return sorting.sort(self) as! [Element]
+    }
+    
+    /// Sorts array of `FileObject`s by criterias set in attributes.
+    public mutating func sorted(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) {
+        self = self.sort(by: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
+    }
+}
+
+public extension Sequence where Iterator.Element == UInt8 {
+    func hexString() -> String {
+        return self.map{String(format: "%02X", $0)}.joined()
+    }
+}
+
+public extension URLFileResourceType {
+    /// **FileProvider** returns corresponding `URLFileResourceType` of a `FileAttributeType` value
+    public init(fileTypeValue: FileAttributeType) {
+        switch fileTypeValue {
+        case FileAttributeType.typeCharacterSpecial: self = .characterSpecial
+        case FileAttributeType.typeDirectory: self = .directory
+        case FileAttributeType.typeBlockSpecial: self = .blockSpecial
+        case FileAttributeType.typeRegular: self = .regular
+        case FileAttributeType.typeSymbolicLink: self = .symbolicLink
+        case FileAttributeType.typeSocket: self = .socket
+        case FileAttributeType.typeUnknown: self = .unknown
+        default: self = .unknown
+        }
+    }
+}
+
+public extension URLResourceKey {
+    /// **FileProvider** returns url of file object.
+    public static let fileURLKey = URLResourceKey(rawValue: "NSURLFileURLKey")
+    /// **FileProvider** returns modification date of file in server
+    public static let serverDateKey = URLResourceKey(rawValue: "NSURLServerDateKey")
+    /// **FileProvider** returns HTTP ETag string of remote resource
+    public static let entryTagKey = URLResourceKey(rawValue: "NSURLEntryTagKey")
+    /// **FileProvider** returns MIME type of file, if returned by server
+    public static let mimeTypeKey = URLResourceKey(rawValue: "NSURLMIMETypeIdentifierKey")
+    /// **FileProvider** returns either file is encrypted or not
+    public static let isEncryptedKey = URLResourceKey(rawValue: "NSURLIsEncryptedKey")
+    /// **FileProvider** count of items in directory
+    public static let childrensCount = URLResourceKey(rawValue: "MFPURLChildrensCount")
+}
+
+public extension ProgressUserInfoKey {
+    /// **FileProvider** returns associated `FileProviderOperationType`
+    public static let fileProvderOperationTypeKey = ProgressUserInfoKey("MFPOperationTypeKey")
+    /// **FileProvider** returns start date/time of operation
+    public static let startingTimeKey = ProgressUserInfoKey("NSProgressStartingTimeKey")
+}
+
+internal extension URL {
+    var uw_scheme: String {
+        return self.scheme ?? ""
+    }
+    
+    var fileIsDirectory: Bool {
+        return (try? self.resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory ?? false
+    }
+    
+    var fileSize: Int64 {
+        return Int64((try? self.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1)
+    }
+    
+    var fileExists: Bool {
+        return self.isFileURL && FileManager.default.fileExists(atPath: self.path)
+    }
+}
+
+public extension URLRequest {
+    /// Defines HTTP Authentication method required to access
+    public enum AuthenticationType {
+        /// Basic method for authentication
+        case basic
+        /// Digest method for authentication
+        case digest
+        /// OAuth 1.0 method for authentication (OAuth)
+        case oAuth1
+        /// OAuth 2.0 method for authentication (Bearer)
+        case oAuth2
+    }
+}
+
+struct Quality<T> {
+    let value: T
+    let quality: Float
+    
+    var stringifed: String {
+        var representaion: String = String(describing: value)
+        let quality: Float = min(1, max(self.quality, 0))
+        if let value = value as? Locale {
+            representaion = value.identifier.replacingOccurrences(of: "_", with: "-")
+        }
+        if let value = value as? String.Encoding {
+            let cfEncoding = CFStringConvertNSStringEncodingToEncoding(value.rawValue)
+            representaion = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? ?? "*"
+        }
+        let qualityDesc = String(format: "%.1f", quality)
+        return "\(representaion); q=\(qualityDesc)"
+    }
+}
+
+internal extension URLRequest {
+    mutating func set(httpAuthentication credential: URLCredential?, with type: AuthenticationType) {
+        func base64(_ str: String) -> String {
+            let plainData = str.data(using: .utf8)
+            let base64String = plainData!.base64EncodedString(options: [])
+            return base64String
+        }
+        
+        guard let credential = credential else { return }
+        switch type {
+        case .basic:
+            let user = credential.user?.replacingOccurrences(of: ":", with: "") ?? ""
+            let pass = credential.password ?? ""
+            let authStr = "\(user):\(pass)"
+            if let base64Auth = authStr.data(using: .utf8)?.base64EncodedString() {
+                self.setValue("Basic \(base64Auth)", forHTTPHeaderField: "Authorization")
+            }
+        case .digest:
+            // handled by RemoteSessionDelegate
+            break
+        case .oAuth1:
+            if let oauth = credential.password {
+                self.setValue("OAuth \(oauth)", forHTTPHeaderField: "Authorization")
+            }
+        case .oAuth2:
+            if let bearer = credential.password {
+                self.setValue("Bearer \(bearer)", forHTTPHeaderField: "Authorization")
+            }
+        }
+    }
+    
+    mutating func set(httpAcceptCharset acceptCharset: String.Encoding) {
+        let cfEncoding = CFStringConvertNSStringEncodingToEncoding(acceptCharset.rawValue)
+        if let charsetString = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? {
+            self.addValue(charsetString, forHTTPHeaderField: "Accept-Charset")
+        }
+    }
+    
+    mutating func set(httpAcceptCharset acceptCharset: Quality<String.Encoding>) {
+        self.addValue(acceptCharset.stringifed, forHTTPHeaderField: "Accept-Charset")
+    }
+    
+    mutating func set(httpAcceptCharsets acceptCharsets: [String.Encoding]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Charset")
+        for charset in acceptCharsets {
+            let cfEncoding = CFStringConvertNSStringEncodingToEncoding(charset.rawValue)
+            if let charsetString = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? {
+                self.addValue(charsetString, forHTTPHeaderField: "Accept-Charset")
+            }
+        }
+    }
+    
+    mutating func set(httpAcceptCharsets acceptCharsets: [Quality<String.Encoding>]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Charset")
+        for charset in acceptCharsets.sorted(by: { $0.quality > $1.quality }) {
+            self.addValue(charset.stringifed, forHTTPHeaderField: "Accept-Charset")
+        }
+    }
+    
+    enum Encoding: String {
+        case all = "*"
+        case identity
+        case gzip
+        case deflate
+    }
+    
+    mutating func set(httpAcceptEncoding acceptEncoding: Encoding) {
+        self.addValue(acceptEncoding.rawValue, forHTTPHeaderField: "Accept-Encoding")
+    }
+    
+    mutating func set(httpAcceptEncoding acceptEncoding: Quality<Encoding>) {
+        self.addValue(acceptEncoding.stringifed, forHTTPHeaderField: "Accept-Encoding")
+    }
+    
+    mutating func set(httpAcceptEncodings acceptEncodings: [Encoding]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Encoding")
+        for encoding in acceptEncodings {
+            self.addValue(encoding.rawValue, forHTTPHeaderField: "Accept-Encoding")
+        }
+    }
+    
+    mutating func set(httpAcceptEncodings acceptEncodings: [Quality<Encoding>]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Encoding")
+        for encoding in acceptEncodings.sorted(by: { $0.quality > $1.quality }) {
+            self.addValue(encoding.stringifed, forHTTPHeaderField: "Accept-Encoding")
+        }
+    }
+    
+    mutating func set(httpAcceptLanguage acceptLanguage: Locale) {
+        let langCode = acceptLanguage.identifier.replacingOccurrences(of: "_", with: "-")
+        self.addValue(langCode, forHTTPHeaderField: "Accept-Language")
+    }
+    
+    mutating func set(httpAcceptLanguage acceptLanguage: Quality<Locale>) {
+        self.addValue(acceptLanguage.stringifed, forHTTPHeaderField: "Accept-Language")
+    }
+    
+    mutating func set(httpAcceptLanguages acceptLanguages: [Locale]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Language")
+        for lang in acceptLanguages {
+            let langCode = lang.identifier.replacingOccurrences(of: "_", with: "-")
+            self.addValue(langCode, forHTTPHeaderField: "Accept-Language")
+        }
+    }
+    
+    mutating func set(httpAcceptLanguages acceptLanguages: [Quality<Locale>]) {
+        self.setValue(nil, forHTTPHeaderField: "Accept-Language")
+        for lang in acceptLanguages.sorted(by: { $0.quality > $1.quality} ) {
+            self.addValue(lang.stringifed, forHTTPHeaderField: "Accept-Language")
+        }
+    }
+    
+    mutating func set(httpRangeWithOffset offset: Int64, length: Int) {
+        if length > 0 {
+            self.setValue("bytes=\(offset)-\(offset + Int64(length) - 1)", forHTTPHeaderField: "Range")
+        } else if offset > 0 && length < 0 {
+            self.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
+        }
+    }
+    
+    mutating func set(httpRange range: Range<Int>) {
+        let range = max(0, range.lowerBound)..<range.upperBound
+        if range.upperBound < Int.max && range.count > 0 {
+            self.setValue("bytes=\(range.lowerBound)-\(range.upperBound - 1)", forHTTPHeaderField: "Range")
+        } else if range.lowerBound > 0 {
+            self.setValue("bytes=\(range.lowerBound)-", forHTTPHeaderField: "Range")
+        }
+    }
+    
+    struct ContentMIMEType: RawRepresentable {
+        public var rawValue: String
+        public typealias RawValue = String
+        
+        public init(rawValue: String) {
+            self.rawValue = rawValue
+        }
+        
+        static let javascript = ContentMIMEType(rawValue: "application/javascript")
+        static let json = ContentMIMEType(rawValue: "application/json")
+        static let pdf = ContentMIMEType(rawValue: "application/pdf")
+        static let stream = ContentMIMEType(rawValue: "application/octet-stream")
+        static let zip = ContentMIMEType(rawValue: "application/zip")
+        
+        // Texts
+        static let css = ContentMIMEType(rawValue: "text/css")
+        static let html = ContentMIMEType(rawValue: "text/html")
+        static let plainText = ContentMIMEType(rawValue: "text/plain")
+        static let xml = ContentMIMEType(rawValue: "text/xml")
+        
+        // Images
+        static let gif = ContentMIMEType(rawValue: "image/gif")
+        static let jpeg = ContentMIMEType(rawValue: "image/jpeg")
+        static let png = ContentMIMEType(rawValue: "image/png")
+    }
+    
+    mutating func set(httpContentType contentType: ContentMIMEType, charset: String.Encoding? = nil) {
+        var parameter = ""
+        if let charset = charset {
+            let cfEncoding = CFStringConvertNSStringEncodingToEncoding(charset.rawValue)
+            if let charsetString = CFStringConvertEncodingToIANACharSetName(cfEncoding) as String? {
+                parameter = ";charset=" + charsetString
+            }
+        }
+        
+        self.setValue(contentType.rawValue + parameter, forHTTPHeaderField: "Content-Type")
+    }
+    
+    mutating func set(dropboxArgKey requestDictionary: [String: AnyObject]) {
+        guard let jsonData = try? JSONSerialization.data(withJSONObject: requestDictionary, options: []) else {
+            return
+        }
+        guard var jsonString = String(data: jsonData, encoding: .utf8) else { return }
+        jsonString = jsonString.asciiEscaped().replacingOccurrences(of: "\\/", with: "/")
+        
+        self.setValue(jsonString, forHTTPHeaderField: "Dropbox-API-Arg")
+    }
+}
+
+internal extension CharacterSet {
+    static let filePathAllowed = CharacterSet.urlPathAllowed.subtracting(CharacterSet(charactersIn: ":"))
+}
+
+internal extension Data {
+    internal var isPDF: Bool {
+        return self.count > 4 && self.scanString(length: 4, using: .ascii) == "%PDF"
+    }
+    
+    init? (jsonDictionary dictionary: [String: AnyObject]) {
+        guard let data = try? JSONSerialization.data(withJSONObject: dictionary, options: []) else {
+            return nil
+        }
+        self = data
+    }
+    
+    func deserializeJSON() -> [String: AnyObject]? {
+        if let dic = try? JSONSerialization.jsonObject(with: self, options: []) as? [String: AnyObject] {
+            return dic
+        }
+        return nil
+    }
+    
+    init<T>(value: T) {
+        var value = value
+        self = Data(buffer: UnsafeBufferPointer(start: &value, count: 1))
+    }
+    
+    func scanValue<T>() -> T? {
+        guard MemoryLayout<T>.size <= self.count else { return nil }
+        return self.withUnsafeBytes { $0.pointee }
+    }
+    
+    func scanValue<T>(start: Int) -> T? {
+        let length = MemoryLayout<T>.size
+        guard self.count >= start + length else { return nil }
+        return self.subdata(in: start..<start+length).withUnsafeBytes { $0.pointee }
+    }
+    
+    func scanString(start: Int = 0, length: Int, using encoding: String.Encoding = .utf8) -> String? {
+        guard self.count >= start + length else { return nil }
+        return String(data: self.subdata(in: start..<start+length), encoding: encoding)
+    }
+    
+    static func mapMemory<T, U>(from: T) -> U? {
+        guard MemoryLayout<T>.size >= MemoryLayout<U>.size else { return nil }
+        let data = Data(value: from)
+        return data.scanValue()
+    }
+}
+
+internal extension String {
+    init? (jsonDictionary: [String: AnyObject]) {
+        guard let data = Data(jsonDictionary: jsonDictionary) else {
+            return nil
+        }
+        self.init(data: data, encoding: .utf8)
+    }
+    
+    func deserializeJSON(using encoding: String.Encoding = .utf8) -> [String: AnyObject]? {
+        guard let data = self.data(using: encoding) else {
+            return nil
+        }
+        return data.deserializeJSON()
+    }
+    
+    func asciiEscaped() -> String {
+        var res = ""
+        for char in self.unicodeScalars {
+            let substring = String(char)
+            if substring.canBeConverted(to: .ascii) {
+                res.append(substring)
+            } else {
+                res = res.appendingFormat("\\u%04x", char.value)
+            }
+        }
+        return res
+    }
+}
+
+#if swift(>=4.0)
+#else
+extension String {
+    var count: Int {
+        return self.characters.count
+    }
+}
+#endif
+
+internal extension TimeInterval {
+    internal var formatshort: String {
+        var result = "0:00"
+        if self < TimeInterval(Int32.max) {
+            result = ""
+            var time = DateComponents()
+            time.hour   = Int(self / 3600)
+            time.minute = Int((self.truncatingRemainder(dividingBy: 3600)) / 60)
+            time.second = Int(self.truncatingRemainder(dividingBy: 60))
+            let formatter = NumberFormatter()
+            formatter.paddingCharacter = "0"
+            formatter.minimumIntegerDigits = 2
+            formatter.maximumFractionDigits = 0
+            let formatterFirst = NumberFormatter()
+            formatterFirst.maximumFractionDigits = 0
+            if time.hour! > 0 {
+                result = "\(formatterFirst.string(from: NSNumber(value: time.hour!))!):\(formatter.string(from: NSNumber(value: time.minute!))!):\(formatter.string(from: NSNumber(value: time.second!))!)"
+            } else {
+                result = "\(formatterFirst.string(from: NSNumber(value: time.minute!))!):\(formatter.string(from: NSNumber(value: time.second!))!)"
+            }
+        }
+        result = result.trimmingCharacters(in: CharacterSet(charactersIn: ": "))
+        return result
+    }
+}
+
+public extension Date {
+    /// Date formats used commonly in internet messaging defined by various RFCs.
+    public enum RFCStandards: String {
+        /// Date format defined by usenet, commonly used in old implementations.
+        case rfc850 = "EEEE',' dd'-'MMM'-'yy HH':'mm':'ss z"
+        /// Date format defined by RFC 1132 for http.
+        case rfc1123 = "EEE',' dd' 'MMM' 'yyyy HH':'mm':'ss z"
+        /// Date format defined by ISO 8601, also defined in RFC 3339. Used by Dropbox.
+        case iso8601 = "yyyy'-'MM'-'dd'T'HH':'mm':'ssZ"
+        /// Date string returned by asctime() function.
+        case asctime = "EEE MMM d HH':'mm':'ss yyyy"
+        
+        /// Equivalent to and defined by RFC 1123.
+        public static let http = RFCStandards.rfc1123
+        /// Equivalent to and defined by ISO 8610.
+        public static let rfc3339 = RFCStandards.iso8601
+        /// Equivalent to and defined by RFC 850.
+        public static let usenet = RFCStandards.rfc850
+        
+        // Sorted by commonness
+        fileprivate static let allValues: [RFCStandards] = [.rfc1123, .rfc850, .iso8601, .asctime]
+    }
+    
+    /// Checks date string against various RFC standards and returns `Date`.
+    public init?(rfcString: String) {
+        let dateFor: DateFormatter = DateFormatter()
+        dateFor.locale = Locale(identifier: "en_US")
+        
+        for standard in RFCStandards.allValues {
+            dateFor.dateFormat = standard.rawValue
+            if let date = dateFor.date(from: rfcString) {
+                self = date
+                return
+            }
+        }
+        
+        return nil
+    }
+    
+    /// Formats date according to RFCs standard.
+    public func format(with standard: RFCStandards, locale: Locale? = nil, timeZone: TimeZone? = nil) -> String {
+        let fm = DateFormatter()
+        fm.dateFormat = standard.rawValue
+        fm.timeZone = timeZone ?? TimeZone(identifier: "UTC")
+        fm.locale = locale ?? Locale(identifier: "en_US_POSIX")
+        return fm.string(from: self)
+    }
+}
+
+internal extension NSPredicate {
+    func findValue(forKey key: String?, operator op: NSComparisonPredicate.Operator? = nil) -> Any? {
+        let val = findAllValues(forKey: key).lazy.filter { (op == nil || $0.operator == op!) && !$0.not }
+        return val.first?.value
+    }
+    
+    func findAllValues(forKey key: String?) -> [(value: Any, operator: NSComparisonPredicate.Operator, not: Bool)] {
+        if let cQuery = self as? NSCompoundPredicate {
+            let find = cQuery.subpredicates.flatMap { ($0 as! NSPredicate).findAllValues(forKey: key) }
+            if cQuery.compoundPredicateType == .not {
+                return find.map { return ($0.value, $0.operator, !$0.not) }
+            }
+            return find
+        } else if let cQuery = self as? NSComparisonPredicate {
+            if cQuery.leftExpression.expressionType == .keyPath, key == nil || cQuery.leftExpression.keyPath == key!, let const = cQuery.rightExpression.constantValue {
+                return [(value: const, operator: cQuery.predicateOperatorType, false)]
+            }
+            if cQuery.rightExpression.expressionType == .keyPath, key == nil || cQuery.rightExpression.keyPath == key!, let const = cQuery.leftExpression.constantValue {
+                return [(value: const, operator: cQuery.predicateOperatorType, false)]
+            }
+            return []
+        } else {
+            return []
+        }
+    }
+}
+
+func ~=<T>(pattern: (T) -> Bool, value: T) -> Bool {
+    return pattern(value)
+}
+
+func hasPrefix(_ prefix: String) -> (_ value: String) -> Bool {
+    return { (value: String) -> Bool in
+        value.hasPrefix(prefix)
+    }
+}
+
+func hasSuffix(_ suffix: String) -> (_ value: String) -> Bool {
+    return { (value: String) -> Bool in
+        value.hasSuffix(suffix)
+    }
+}
@@ -0,0 +1,445 @@
+// Originally based on CryptoSwift by Marcin Krzyżanowski <marcin.krzyzanowski@gmail.com>
+// Copyright (C) 2014 Marcin Krzyżanowski <marcin.krzyzanowski@gmail.com>
+// This software is provided 'as-is', without any express or implied warranty.
+//
+// In no event will the authors be held liable for any damages arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
+//
+// - The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation is required.
+// - Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+// - This notice may not be removed or altered from any source or binary distribution.
+
+import Foundation
+
+protocol SHA2Variant {
+    static var size: Int { get }
+    static var h: [UInt64] { get }
+    static var k: [UInt64] { get }
+    
+    static func resultingArray<T>(_ hh:[T]) -> ArraySlice<T>
+    static func calculate(_ message: [UInt8]) -> [UInt8]
+}
+
+protocol SHA2Variant32: SHA2Variant { }
+protocol SHA2Variant64: SHA2Variant { }
+
+extension SHA2Variant32 {
+    static var size: Int {
+        return 64
+    }
+    
+    static var k: [UInt64] {
+        return [0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+                0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+                0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+                0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+                0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+                0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+                0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+                0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2]
+    }
+    
+    // codebeat:disable[ABC]
+    static func calculate(_ message: [UInt8]) -> [UInt8] {
+        var tmpMessage = message
+        
+        let len = Self.size
+        
+        // Step 1. Append Padding Bits
+        tmpMessage.append(0x80) // append one bit (UInt8 with one bit) to message
+        
+        // append "0" bit until message length in bits ≡ 448 (mod 512)
+        var msgLength = tmpMessage.count
+        var counter = 0
+        
+        while msgLength % len != (len - 8) {
+            counter += 1
+            msgLength += 1
+        }
+        
+        tmpMessage.append(contentsOf: [UInt8](repeating: 0, count: counter))
+        
+        // hash values
+        var hh: [UInt32] = Self.h.map { UInt32($0) }
+        let k = Self.k
+        
+        // append message length, in a 64-bit big-endian integer. So now the message length is a multiple of 512 bits.
+        tmpMessage.append(contentsOf: arrayOfBytes(message.count * 8, length: 64 / 8))
+        
+        // Process the message in successive 512-bit chunks:
+        let chunkSizeBytes = 512 / 8 // 64
+        for chunk in BytesSequence(chunkSize: chunkSizeBytes, data: tmpMessage) {
+            // break chunk into sixteen 32-bit words M[j], 0 ≤ j ≤ 15, big-endian
+            // Extend the sixteen 32-bit words into sixty-four 32-bit words:
+            var M:[UInt32] = [UInt32](repeating: 0, count: k.count)
+            for x in 0..<M.count {
+                switch (x) {
+                case 0...15:
+                    let start: Int = chunk.startIndex + (x * MemoryLayout.size(ofValue: M[x]))
+                    let end: Int = start + MemoryLayout.size(ofValue: M[x])
+                    let le = toUInt32Array(chunk[start..<end])[0]
+                    M[x] = le.bigEndian
+                    break
+                default:
+                    let s0 = rotateRight(M[x-15], n: 7) ^ rotateRight(M[x-15], n: 18) ^ (M[x-15] >> 3) //FIXME: n
+                    let s1 = rotateRight(M[x-2], n: 17) ^ rotateRight(M[x-2], n: 19) ^ (M[x-2] >> 10)
+                    let s2 = M[x-16]
+                    let s3 = M[x-7]
+                    M[x] = s2 &+ s0 &+ s3 &+ s1
+                    break
+                }
+            }
+            
+            var A = hh[0], B = hh[1], C = hh[2], D = hh[3], E = hh[4], F = hh[5], G = hh[6], H = hh[7]
+            
+            // Main loop
+            for j in 0..<k.count {
+                let s0 = rotateRight(A,n: 2) ^ rotateRight(A,n: 13) ^ rotateRight(A,n: 22)
+                let maj = (A & B) ^ (A & C) ^ (B & C)
+                let t2 = s0 &+ maj
+                let s1 = rotateRight(E,n: 6) ^ rotateRight(E,n: 11) ^ rotateRight(E,n: 25)
+                let ch = (E & F) ^ ((~E) & G)
+                let t1 = H &+ s1 &+ ch &+ UInt32(k[j]) &+ M[j]
+                
+                H = G; G = F; F = E; E = D &+ t1
+                D = C; C = B; B = A; A = t1 &+ t2
+            }
+            
+            hh[0] = (hh[0] &+ A)
+            hh[1] = (hh[1] &+ B)
+            hh[2] = (hh[2] &+ C)
+            hh[3] = (hh[3] &+ D)
+            hh[4] = (hh[4] &+ E)
+            hh[5] = (hh[5] &+ F)
+            hh[6] = (hh[6] &+ G)
+            hh[7] = (hh[7] &+ H)
+        }
+        
+        // Produce the final hash value (big-endian) as a 160 bit number:
+        var result = [UInt8]()
+        result.reserveCapacity(hh.count / 4)
+        Self.resultingArray(hh).forEach {
+            let item = $0.bigEndian
+            #if swift(>=4.0)
+                result.append(UInt8(truncatingIfNeeded: item))
+                result.append(UInt8(truncatingIfNeeded: item >> 8))
+                result.append(UInt8(truncatingIfNeeded: item >> 16))
+                result.append(UInt8(truncatingIfNeeded: item >> 24))
+            #else
+                result.append(UInt8(item))
+                result.append(UInt8((item >> 8)  & 0xFF))
+                result.append(UInt8((item >> 16) & 0xFF))
+                result.append(UInt8((item >> 24) & 0xFF))
+            #endif
+            
+        }
+        return result
+    }
+    // codebeat:enable[ABC]
+}
+
+extension SHA2Variant64 {
+    static var size: Int {
+        return 128
+    }
+    
+    static var k: [UInt64] {
+        return [0x428a2f98d728ae22, 0x7137449123ef65cd, 0xb5c0fbcfec4d3b2f, 0xe9b5dba58189dbbc, 0x3956c25bf348b538,
+                0x59f111f1b605d019, 0x923f82a4af194f9b, 0xab1c5ed5da6d8118, 0xd807aa98a3030242, 0x12835b0145706fbe,
+                0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, 0x80deb1fe3b1696b1, 0x9bdc06a725c71235,
+                0xc19bf174cf692694, 0xe49b69c19ef14ad2, 0xefbe4786384f25e3, 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65,
+                0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, 0x983e5152ee66dfab,
+                0xa831c66d2db43210, 0xb00327c898fb213f, 0xbf597fc7beef0ee4, 0xc6e00bf33da88fc2, 0xd5a79147930aa725,
+                0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed,
+                0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, 0x81c2c92e47edaee6, 0x92722c851482353b,
+                0xa2bfe8a14cf10364, 0xa81a664bbc423001, 0xc24b8b70d0f89791, 0xc76c51a30654be30, 0xd192e819d6ef5218,
+                0xd69906245565a910, 0xf40e35855771202a, 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53,
+                0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373,
+                0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, 0x84c87814a1f0ab72, 0x8cc702081a6439ec,
+                0x90befffa23631e28, 0xa4506cebde82bde9, 0xbef9a3f7b2c67915, 0xc67178f2e372532b, 0xca273eceea26619c,
+                0xd186b8c721c0c207, 0xeada7dd6cde0eb1e, 0xf57d4f7fee6ed178, 0x06f067aa72176fba, 0x0a637dc5a2c898a6,
+                0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc,
+                0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817]
+    }
+    
+    // codebeat:disable[ABC]
+    static func calculate(_ message: [UInt8]) -> [UInt8] {
+        var tmpMessage = message
+        
+        let len = Self.size
+        
+        // Step 1. Append Padding Bits
+        tmpMessage.append(0x80) // append one bit (UInt8 with one bit) to message
+        
+        // append "0" bit until message length in bits ≡ 448 (mod 512)
+        var msgLength = tmpMessage.count
+        var counter = 0
+        
+        while msgLength % len != (len - 8) {
+            counter += 1
+            msgLength += 1
+        }
+        
+        tmpMessage += [UInt8](repeating: 0, count: counter)
+        
+        // hash values
+        var hh: [UInt64] = Self.h
+        let k = Self.k
+        
+        // append message length, in a 64-bit big-endian integer. So now the message length is a multiple of 512 bits.
+        tmpMessage += arrayOfBytes(message.count * 8, length: 64 / 8)
+        
+        // Process the message in successive 1024-bit chunks:
+        let chunkSizeBytes = 1024 / 8 // 128
+        for chunk in BytesSequence(chunkSize: chunkSizeBytes, data: tmpMessage) {
+            // break chunk into sixteen 64-bit words M[j], 0 ≤ j ≤ 15, big-endian
+            // Extend the sixteen 64-bit words into eighty 64-bit words:
+            var M = [UInt64](repeating: 0, count: k.count)
+            for x in 0..<M.count {
+                switch (x) {
+                case 0...15:
+                    let start = chunk.startIndex + (x * MemoryLayout.size(ofValue: M[x]))
+                    let end = start + MemoryLayout.size(ofValue: M[x])
+                    let le = toUInt64Array(chunk[start..<end])[0]
+                    M[x] = le.bigEndian
+                    break
+                default:
+                    let s0 = rotateRight(M[x-15], n: 1) ^ rotateRight(M[x-15], n: 8) ^ (M[x-15] >> 7)
+                    let s1 = rotateRight(M[x-2], n: 19) ^ rotateRight(M[x-2], n: 61) ^ (M[x-2] >> 6)
+                    let s2 = M[x-16]
+                    let s3 = M[x-7]
+                    M[x] = s2 &+ s0 &+ s3 &+ s1
+                    break
+                }
+            }
+            
+            var A = hh[0], B = hh[1], C = hh[2], D = hh[3], E = hh[4], F = hh[5], G = hh[6], H = hh[7]
+            
+            // Main loop
+            for j in 0..<k.count {
+                let s0 = rotateRight(A,n: 28) ^ rotateRight(A,n: 34) ^ rotateRight(A,n: 39) //FIXME: n:
+                let maj = (A & B) ^ (A & C) ^ (B & C)
+                let t2 = s0 &+ maj
+                let s1 = rotateRight(E,n: 14) ^ rotateRight(E,n: 18) ^ rotateRight(E,n: 41)
+                let ch = (E & F) ^ ((~E) & G)
+                let t1 = H &+ s1 &+ ch &+ k[j] &+ UInt64(M[j])
+                
+                H = G; G = F; F = E; E = D &+ t1
+                D = C; C = B; B = A; A = t1 &+ t2
+            }
+            
+            hh[0] = (hh[0] &+ A)
+            hh[1] = (hh[1] &+ B)
+            hh[2] = (hh[2] &+ C)
+            hh[3] = (hh[3] &+ D)
+            hh[4] = (hh[4] &+ E)
+            hh[5] = (hh[5] &+ F)
+            hh[6] = (hh[6] &+ G)
+            hh[7] = (hh[7] &+ H)
+        }
+        
+        // Produce the final hash value (big-endian)
+        var result = [UInt8]()
+        result.reserveCapacity(hh.count / 4)
+        Self.resultingArray(hh).forEach {
+            let item = $0.bigEndian
+            var partialResult = [UInt8]()
+            partialResult.reserveCapacity(8)
+            for i in 0..<8 {
+                let shift = UInt64(8 * i)
+                partialResult.append(UInt8((item >> shift) & 0xff))
+            }
+            result += partialResult
+        }
+        return result
+    }
+    // codebeat:enable[ABC]
+}
+
+final class SHA256 : SHA2Variant32 {
+    static let h: [UInt64] = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19]
+    
+    static func resultingArray<T>(_ hh: [T]) -> ArraySlice<T> {
+        return ArraySlice(hh)
+    }
+}
+
+final class SHA384 : SHA2Variant64 {
+    static let h: [UInt64] = [0xcbbb9d5dc1059ed8, 0x629a292a367cd507, 0x9159015a3070dd17, 0x152fecd8f70e5939, 0x67332667ffc00b31, 0x8eb44a8768581511, 0xdb0c2e0d64f98fa7, 0x47b5481dbefa4fa4]
+    
+    public static func resultingArray<T>(_ hh: [T]) -> ArraySlice<T> {
+        return hh[0..<6]
+    }
+}
+
+final class SHA512 : SHA2Variant64 {
+    static let h: [UInt64] = [0x6a09e667f3bcc908, 0xbb67ae8584caa73b, 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1, 0x510e527fade682d1, 0x9b05688c2b3e6c1f, 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179]
+    
+    static func resultingArray<T>(_ hh: [T]) -> ArraySlice<T> {
+        return ArraySlice(hh)
+    }
+}
+
+final class SHA2<Variant: SHA2Variant> {
+    static var size: Int {
+        return Variant.size
+    }
+    
+    static func calculate(_ message: [UInt8]) -> [UInt8] {
+        return Variant.calculate(message)
+    }
+}
+
+final class HMAC<Variant: SHA2Variant> {
+    public static func authenticate(message:[UInt8], withKey key: [UInt8]) -> [UInt8] {
+        var key = key
+        
+        if (key.count > Variant.size) {
+            key = Variant.calculate(key)
+        }
+        
+        if (key.count < Variant.size) { // keys shorter than blocksize are zero-padded
+            key = key + [UInt8](repeating: 0, count: Variant.size - key.count)
+        }
+        
+        var opad = [UInt8](repeating: 0x5c, count: Variant.size)
+        for (idx, _) in key.enumerated() {
+            opad[idx] = key[idx] ^ opad[idx]
+        }
+        var ipad = [UInt8](repeating: 0x36, count: Variant.size)
+        for (idx, _) in key.enumerated() {
+            ipad[idx] = key[idx] ^ ipad[idx]
+        }
+        
+        let ipadAndMessageHash = Variant.calculate(ipad + message)
+        let finalHash = Variant.calculate(opad + ipadAndMessageHash);
+        
+        return finalHash
+    }
+    
+    static func authenticate(message: String, withKey key: [UInt8]) -> [UInt8] {
+        return authenticate(message: [UInt8](message.utf8), withKey: key)
+    }
+    
+    static func authenticate(message: Data, withKey key: Data) -> Data {
+        return Data(bytes: authenticate(message: Array(message), withKey: Array(key)))
+    }
+    
+    static func authenticate(message: String, withKey key: Data) -> Data {
+        return Data(bytes: authenticate(message: [UInt8](message.utf8), withKey: Array(key)))
+    }
+}
+
+fileprivate struct BytesSequence: Sequence {
+    let chunkSize: Int
+    let data: [UInt8]
+    
+    init(chunkSize: Int, data: [UInt8]) {
+        self.chunkSize = chunkSize
+        self.data = data
+    }
+    
+    func makeIterator() -> AnyIterator<ArraySlice<UInt8>> {
+        var offset:Int = 0
+        
+        return AnyIterator {
+            let end = Swift.min(self.chunkSize, self.data.count - offset)
+            let result = self.data[offset..<offset + end]
+            offset += result.count
+            return result.count > 0 ? result : nil
+        }
+    }
+}
+
+fileprivate func rotateRight(_ x:UInt16, n:UInt16) -> UInt16 {
+    return (x >> n) | (x << (16 - n))
+}
+
+fileprivate func rotateRight(_ x:UInt32, n:UInt32) -> UInt32 {
+    return (x >> n) | (x << (32 - n))
+}
+
+fileprivate func rotateRight(_ x:UInt64, n:UInt64) -> UInt64 {
+    return ((x >> n) | (x << (64 - n)))
+}
+
+fileprivate func toUInt32Array(_ slice: ArraySlice<UInt8>) -> Array<UInt32> {
+    var result = Array<UInt32>()
+    result.reserveCapacity(16)
+    
+    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: MemoryLayout<UInt32>.size) {
+        let val1:UInt32 = (UInt32(slice[idx.advanced(by: 3)]) << 24)
+        let val2:UInt32 = (UInt32(slice[idx.advanced(by: 2)]) << 16)
+        let val3:UInt32 = (UInt32(slice[idx.advanced(by: 1)]) << 8)
+        let val4:UInt32 = UInt32(slice[idx])
+        let val:UInt32 = val1 | val2 | val3 | val4
+        result.append(val)
+    }
+    return result
+}
+
+fileprivate func toUInt64Array(_ slice: ArraySlice<UInt8>) -> Array<UInt64> {
+    var result = Array<UInt64>()
+    result.reserveCapacity(32)
+    for idx in stride(from: slice.startIndex, to: slice.endIndex, by: MemoryLayout<UInt64>.size) {
+        var val:UInt64 = 0
+        val |= UInt64(slice[idx.advanced(by: 7)]) << 56
+        val |= UInt64(slice[idx.advanced(by: 6)]) << 48
+        val |= UInt64(slice[idx.advanced(by: 5)]) << 40
+        val |= UInt64(slice[idx.advanced(by: 4)]) << 32
+        val |= UInt64(slice[idx.advanced(by: 3)]) << 24
+        val |= UInt64(slice[idx.advanced(by: 2)]) << 16
+        val |= UInt64(slice[idx.advanced(by: 1)]) << 8
+        val |= UInt64(slice[idx.advanced(by: 0)]) << 0
+        result.append(val)
+    }
+    return result
+}
+
+fileprivate func arrayOfBytes<T>(_ value:T, length:Int? = nil) -> [UInt8] {
+    let totalBytes = length ?? MemoryLayout<T>.size
+    
+    let valuePointer = UnsafeMutablePointer<T>.allocate(capacity: 1)
+    
+    valuePointer.pointee = value
+    
+    let bytesPointer = UnsafeMutableRawPointer(valuePointer).assumingMemoryBound(to: UInt8.self)
+    var bytes = [UInt8](repeating: 0, count: totalBytes)
+    for j in 0..<min(MemoryLayout<T>.size,totalBytes) {
+        bytes[totalBytes - 1 - j] = (bytesPointer + j).pointee
+    }
+    
+    valuePointer.deinitialize()
+    valuePointer.deallocate(capacity: 1)
+    
+    return bytes
+}
+
+public extension String {
+    public func fp_sha256() -> [UInt8] {
+        return SHA2<SHA256>.calculate([UInt8](self.utf8))
+    }
+    
+    public func fp_sha384() -> [UInt8] {
+        return SHA2<SHA384>.calculate([UInt8](self.utf8))
+    }
+    
+    public func fp_sha512() -> [UInt8] {
+        return SHA2<SHA512>.calculate([UInt8](self.utf8))
+    }
+}
+
+public extension Data {
+    public func fp_sha256() -> [UInt8] {
+        return SHA2<SHA256>.calculate(Array(self))
+    }
+    
+    public func fp_sha384() -> [UInt8] {
+        return SHA2<SHA384>.calculate(Array(self))
+    }
+    
+    public func fp_sha512() -> [UInt8] {
+        return SHA2<SHA512>.calculate(Array(self))
+    }
+}
@@ -0,0 +1,867 @@
+//
+//  FTPFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/**
+ Allows accessing to FTP files and directories. This provider doesn't cache or save files internally.
+ It's a complete reimplementation and doesn't use CFNetwork deprecated API.
+ */
+open class FTPFileProvider: FileProviderBasicRemote, FileProviderOperations, FileProviderReadWrite {
+    open class var type: String { return "FTP" }
+    open let baseURL: URL?
+    /// **OBSOLETED** Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
+    @available(*, obsoleted: 0.22, message: "This property is redundant with almost no use internally.")
+    open var currentPath: String = ""
+    
+    open var dispatch_queue: DispatchQueue
+    open var operation_queue: OperationQueue {
+        willSet {
+            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
+        }
+    }
+    
+    open weak var delegate: FileProviderDelegate?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
+    open private(set) var cache: URLCache?
+    public var useCache: Bool
+    public var validatingCache: Bool
+    
+    /// Determine either FTP session is in passive or active mode.
+    public let passiveMode: Bool
+    
+    /// Force to use URLSessionDownloadTask/URLSessionDataTask when possible
+    public var useAppleImplementation = true
+    
+    fileprivate var _session: URLSession!
+    internal var sessionDelegate: SessionDelegate?
+    public var session: URLSession {
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let config = URLSessionConfiguration.default
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
+                _session.sessionDescription = UUID().uuidString
+                initEmptySessionHandler(_session.sessionDescription!)
+            }
+            return _session
+        }
+        
+        set {
+            assert(newValue.delegate is SessionDelegate, "session instances should have a SessionDelegate instance as delegate.")
+            _session = newValue
+            if _session.sessionDescription?.isEmpty ?? true {
+                _session.sessionDescription = UUID().uuidString
+            }
+            self.sessionDelegate = newValue.delegate as? SessionDelegate
+            initEmptySessionHandler(_session.sessionDescription!)
+        }
+    }
+    
+    /**
+     Initializer for FTP provider with given username and password.
+     
+     - Note: `passive` value should be set according to server settings and firewall presence.
+     
+     - Parameter baseURL: a url with `ftp://hostaddress/` format.
+     - Parameter passive: FTP server data connection, `true` means passive connection (data connection created by client)
+         and `false` means active connection (data connection created by server). Default is `true` (passive mode).
+     - Parameter credential: a `URLCredential` object contains user and password.
+     - Parameter cache: A URLCache to cache downloaded files and contents. (unimplemented for FTP and should be nil)
+     */
+    public init? (baseURL: URL, passive: Bool = true, credential: URLCredential? = nil, cache: URLCache? = nil) {
+        guard (baseURL.scheme ?? "ftp").lowercased().hasPrefix("ftp") else { return nil }
+        guard baseURL.host != nil else { return nil }
+        var urlComponents = URLComponents(url: baseURL, resolvingAgainstBaseURL: true)!
+        let defaultPort: Int = baseURL.scheme == "ftps" ? 990 : 21
+        urlComponents.port = urlComponents.port ?? defaultPort
+        urlComponents.scheme = urlComponents.scheme ?? "ftp"
+        urlComponents.path = urlComponents.path.hasSuffix("/") ? urlComponents.path : urlComponents.path + "/"
+        
+        self.baseURL =  urlComponents.url!.absoluteURL
+        self.passiveMode = passive
+        self.useCache = false
+        self.validatingCache = true
+        self.cache = cache
+        self.credential = credential
+        
+        #if swift(>=3.1)
+        let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+        let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else { return nil }
+        self.init(baseURL: baseURL, passive: aDecoder.decodeBool(forKey: "passiveMode"), credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.useCache        = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
+        self.useAppleImplementation = aDecoder.decodeBool(forKey: "useAppleImplementation")
+    }
+    
+    public func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.useCache, forKey: "useCache")
+        aCoder.encode(self.validatingCache, forKey: "validatingCache")
+        aCoder.encode(self.useAppleImplementation, forKey: "useAppleImplementation")
+        aCoder.encode(self.passiveMode, forKey: "passiveMode")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = FTPFileProvider(baseURL: self.baseURL!, credential: self.credential, cache: self.cache)!
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        copy.useAppleImplementation = self.useAppleImplementation
+        return copy
+    }
+    
+    deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
+    }
+    
+    internal var serverSupportsRFC3659: Bool = true
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping ([FileObject], Error?) -> Void) {
+        self.contentsOfDirectory(path: path, rfc3659enabled: serverSupportsRFC3659, completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameter path: path to target directory. If empty, root will be iterated.
+     - Parameter rfc3659enabled: uses MLST command instead of old LIST to get files attributes, default is `true`.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+     - Parameter contents: An array of `FileObject` identifying the the directory entries.
+     - Parameter error: Error returned by system.
+     */
+    open func contentsOfDirectory(path apath: String, rfc3659enabled: Bool , completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
+        let path = ftpPath(apath)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler([], error)
+                }
+                return
+            }
+            
+            self.ftpList(task, of: self.ftpPath(path), useMLST: rfc3659enabled, completionHandler: { (contents, error) in
+                defer {
+                    self.ftpQuit(task)
+                }
+                if let error = error {
+                    if ((error as NSError).domain == URLError.errorDomain && (error as NSError).code == URLError.unsupportedURL.rawValue) {
+                        self.contentsOfDirectory(path: path, rfc3659enabled: false, completionHandler: completionHandler)
+                        return
+                    }
+                    
+                    self.dispatch_queue.async {
+                        completionHandler([], error)
+                    }
+                    return
+                }
+                
+                
+                let files: [FileObject] = contents.flatMap {
+                    rfc3659enabled ? self.parseMLST($0, in: path) : self.parseUnixList($0, in: path)
+                }
+                
+                self.dispatch_queue.async {
+                    completionHandler(files, nil)
+                }
+            })
+        }
+    }
+    
+    open func attributesOfItem(path: String, completionHandler: @escaping (FileObject?, Error?) -> Void) {
+        self.attributesOfItem(path: path, rfc3659enabled: serverSupportsRFC3659, completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameter path: path to target directory. If empty, attributes of root will be returned.
+     - Parameter rfc3659enabled: uses MLST command instead of old LIST to get files attributes, default is true.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+         `attributes`: A `FileObject` containing the attributes of the item.
+         `error`: Error returned by system.
+     */
+    open func attributesOfItem(path apath: String, rfc3659enabled: Bool, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
+        let path = ftpPath(apath)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler(nil, error)
+                }
+                return
+            }
+            
+            let command = rfc3659enabled ? "MLST \(path)" : "LIST \(path)"
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                defer {
+                    self.ftpQuit(task)
+                }
+                do {
+                    if let error = error {
+                        throw error
+                    }
+                    
+                    guard let response = response, response.hasPrefix("250") || (response.hasPrefix("50") && rfc3659enabled) else {
+                        throw self.urlError(path, code: .badServerResponse)
+                    }
+                    
+                    if response.hasPrefix("500") {
+                        self.serverSupportsRFC3659 = false
+                        self.attributesOfItem(path: path, rfc3659enabled: false, completionHandler: completionHandler)
+                    }
+                    
+                    let lines = response.components(separatedBy: "\n").flatMap { $0.isEmpty ? nil : $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+                    guard lines.count > 2 else {
+                        throw self.urlError(path, code: .badServerResponse)
+                    }
+                    let file: FileObject? = rfc3659enabled ? self.parseMLST(lines[1], in: path) : self.parseUnixList(lines[1], in: path)
+                    self.dispatch_queue.async {
+                        completionHandler(file, nil)
+                    }
+                } catch {
+                    self.dispatch_queue.async {
+                        completionHandler(nil, error)
+                    }
+                }
+            })
+        }
+    }
+    
+    open func storageProperties(completionHandler: @escaping (_ volume: VolumeObject?) -> Void) {
+        dispatch_queue.async {
+            completionHandler(nil)
+        }
+    }
+    
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let progress = Progress(totalUnitCount: -1)
+        if recursive {
+            return self.recursiveList(path: path, useMLST: true, foundItemsHandler: { items in
+                if let foundItemHandler = foundItemHandler {
+                    for item in items where query.evaluate(with: item.mapPredicate()) {
+                        foundItemHandler(item)
+                    }
+                    progress.totalUnitCount = Int64(items.count)
+                }
+            }, completionHandler: {files, error in
+                if let error = error {
+                    completionHandler([], error)
+                    return
+                }
+                
+                let foundFiles = files.filter { query.evaluate(with: $0.mapPredicate()) }
+                completionHandler(foundFiles, nil)
+            })
+        } else {
+            self.contentsOfDirectory(path: path, completionHandler: { (items, error) in
+                if let error = error {
+                    completionHandler([], error)
+                    return
+                }
+                
+                var result = [FileObject]()
+                for item in items where query.evaluate(with: item.mapPredicate()) {
+                    foundItemHandler?(item)
+                    result.append(item)
+                }
+                completionHandler(result, nil)
+            })
+        }
+        
+        return progress
+    }
+    
+    open func url(of path: String?) -> URL {
+        let path = path?.trimmingCharacters(in: CharacterSet(charactersIn: "/ ")).addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? (path ?? "")
+        
+        var baseUrlComponent = URLComponents(url: self.baseURL!, resolvingAgainstBaseURL: true)
+        baseUrlComponent?.user = credential?.user
+        baseUrlComponent?.password = credential?.password
+        return URL(string: path, relativeTo: baseUrlComponent?.url ?? baseURL) ?? baseUrlComponent?.url ?? baseURL!
+    }
+    
+    open func relativePathOf(url: URL) -> String {
+        // check if url derieved from current base url
+        let relativePath = url.relativePath
+        if !relativePath.isEmpty, url.baseURL == self.baseURL {
+            return (relativePath.removingPercentEncoding ?? relativePath).replacingOccurrences(of: "/", with: "", options: .anchored)
+        }
+        
+        if !relativePath.isEmpty, self.baseURL == self.url(of: "/") {
+            return (relativePath.removingPercentEncoding ?? relativePath).replacingOccurrences(of: "/", with: "", options: .anchored)
+        }
+        
+        return relativePath.replacingOccurrences(of: "/", with: "", options: .anchored)
+    }
+    
+    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        self.attributesOfItem(path: "/") { (file, error) in
+            completionHandler(file != nil)
+        }
+    }
+    
+    open weak var fileOperationDelegate: FileOperationDelegate?
+    
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
+        return doOperation(.create(path: path), completionHandler: completionHandler)
+    }
+    
+    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
+    }
+    
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.remove(path: path), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        // check file is not a folder
+        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
+            dispatch_queue.async {
+                completionHandler?(self.urlError(localFile.path, code: .fileIsDirectory))
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: 0)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                return
+            }
+            
+            self.ftpStore(task, filePath: self.ftpPath(toPath), fromData: nil, fromFile: localFile, onTask: { task in
+                weak var weakTask = task
+                progress.cancellationHandler = {
+                    weakTask?.cancel()
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            }, onProgress: { bytesSent, totalSent, expectedBytes in
+                progress.completedUnitCount = totalSent
+                self.delegateNotify(operation, progress: progress.fractionCompleted)
+            }, completionHandler: { (error) in
+                if error != nil {
+                    progress.cancel()
+                }
+                self.ftpQuit(task)
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+            })
+        }
+        
+        return progress
+    }
+    
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        var progress = Progress(totalUnitCount: 0)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        if self.useAppleImplementation {
+            self.attributesOfItem(path: path, completionHandler: { (file, error) in
+                do {
+                    if let error = error {
+                        throw error
+                    }
+                    
+                    if file?.isDirectory ?? false {
+                        throw self.urlError(path, code: .fileIsDirectory)
+                    }
+                } catch {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(operation, error: error)
+                    }
+                    return
+                }
+                
+                progress.totalUnitCount = file?.size ?? 0
+                
+                let task = self.session.downloadTask(with: self.url(of: path))
+                completionHandlersForTasks[self.session.sessionDescription!]?[task.taskIdentifier] = completionHandler
+                downloadCompletionHandlersForTasks[self.session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+                    var error: NSError?
+                    NSFileCoordinator().coordinate(writingItemAt: tempURL, options: .forMoving, writingItemAt: destURL, options: .forReplacing, error: &error, byAccessor: { (tempURL, destURL) in
+                        do {
+                            try FileManager.default.moveItem(at: tempURL, to: destURL)
+                            completionHandler?(nil)
+                        } catch {
+                            completionHandler?(error)
+                        }
+                    })
+                    if let error = error {
+                        completionHandler?(error)
+                    }
+                }
+                task.taskDescription = operation.json
+                task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+                task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+                progress.cancellationHandler = { [weak task] in
+                    task?.cancel()
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                task.resume()
+            })
+        } else {
+            let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+            self.ftpLogin(task) { (error) in
+                if let error = error {
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                    }
+                    return
+                }
+                
+                self.ftpRetrieveFile(task, filePath: self.ftpPath(path), onTask: { task in
+                    weak var weakTask = task
+                    progress.cancellationHandler = {
+                        weakTask?.cancel()
+                    }
+                    progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                }, onProgress: { recevied, totalReceived, totalSize in
+                    progress.totalUnitCount = totalSize
+                    progress.completedUnitCount = totalReceived
+                    self.delegateNotify(operation, progress: progress.fractionCompleted)
+                }) { (tmpurl, error) in
+                    if let error = error {
+                        progress.cancel()
+                        self.dispatch_queue.async {
+                            completionHandler?(error)
+                            self.delegateNotify(operation, error: error)
+                        }
+                        return
+                    }
+                    
+                    if let tmpurl = tmpurl {
+                        try? FileManager.default.moveItem(at: tmpurl, to: destURL)
+                        self.dispatch_queue.async {
+                            completionHandler?(nil)
+                            self.delegateNotify(operation)
+                        }
+                    }
+                }
+            }
+        }
+        return progress
+    }
+    
+    open func contents(path: String, completionHandler: @escaping ((Data?, Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        
+        if self.useAppleImplementation {
+            var progress = Progress(totalUnitCount: 0)
+            progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+            progress.kind = .file
+            progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+            
+            let task = session.downloadTask(with: url(of: path))
+            completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+                if error != nil {
+                    progress.cancel()
+                }
+                completionHandler(nil, error)
+            }
+            downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+                do {
+                    let data = try Data(contentsOf: tempURL)
+                    completionHandler(data, nil)
+                } catch {
+                    completionHandler(nil, error)
+                }
+            }
+            task.taskDescription = operation.json
+            task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+            task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+            progress.cancellationHandler = { [weak task] in
+                task?.cancel()
+            }
+            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            task.resume()
+            return progress
+        } else {
+            return self.contents(path: path, offset: 0, length: -1, completionHandler: completionHandler)
+        }
+    }
+    
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+                self.delegateNotify(operation)
+            }
+            return nil
+        }
+        let progress = Progress(totalUnitCount: 0)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler(nil, error)
+                }
+                return
+            }
+            
+            self.ftpRetrieveData(task, filePath: self.ftpPath(path), from: offset, length: length, onTask: { task in
+                weak var weakTask = task
+                progress.cancellationHandler = {
+                    weakTask?.cancel()
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            }, onProgress: { recevied, totalReceived, totalSize in
+                progress.totalUnitCount = totalSize
+                progress.completedUnitCount = totalReceived
+                self.delegateNotify(operation, progress: progress.fractionCompleted)
+            }) { (data, error) in
+                if let error = error {
+                    progress.cancel()
+                    self.dispatch_queue.async {
+                        completionHandler(nil, error)
+                        self.delegateNotify(operation, error: error)
+                    }
+                    return
+                }
+                
+                if let data = data {
+                    self.dispatch_queue.async {
+                        completionHandler(data, nil)
+                        self.delegateNotify(operation)
+                    }
+                }
+            }
+        }
+        
+        return progress
+    }
+    
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: Int64(data?.count ?? 0))
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                return
+            }
+            
+            let storeHandler = {
+                self.ftpStore(task, filePath: self.ftpPath(path), fromData: data ?? Data(), fromFile: nil, onTask: { task in
+                    weak var weakTask = task
+                    progress.cancellationHandler = {
+                        weakTask?.cancel()
+                    }
+                    progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                }, onProgress: { bytesSent, totalSent, expectedBytes in
+                    progress.completedUnitCount = totalSent
+                    self.delegateNotify(operation, progress: progress.fractionCompleted)
+                }, completionHandler: { (error) in
+                    if error != nil {
+                        progress.cancel()
+                    }
+                    self.ftpQuit(task)
+                    self.dispatch_queue.async {
+                        completionHandler?(error)
+                        self.delegateNotify(operation, error: error)
+                    }
+                })
+            }
+            
+            if overwrite {
+                storeHandler()
+            } else {
+                self.attributesOfItem(path: path, completionHandler: { (file, erroe) in
+                    if file == nil {
+                        storeHandler()
+                    }
+                })
+            }
+        }
+        
+        return progress
+    }
+    
+    /**
+     Creates a symbolic link at the specified path that points to an item at the given path.
+     This method does not traverse symbolic links contained in destination path, making it possible
+     to create symbolic links to locations that do not yet exist.
+     Also, if the final path component is a symbolic link, that link is not followed.
+     
+     - Note: Many servers does't support this functionality.
+     
+     - Parameters:
+       - symbolicLink: The file path at which to create the new symbolic link. The last component of the path issued as the name of the link.
+       - withDestinationPath: The path that contains the item to be pointed to by the link. In other words, this is the destination of the link.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     */
+    open func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
+        let operation = FileOperationType.link(link: path, target: destPath)
+        _=self.doOperation(operation, completionHandler: completionHandler)
+    }
+}
+
+extension FTPFileProvider {
+    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let sourcePath = operation.source
+        let destPath = operation.destination
+        
+        let command: String
+        switch operation {
+        case .create: command = "MKD \(ftpPath(sourcePath))"
+        case .copy: command = "SITE CPFR \(ftpPath(sourcePath))\r\nSITE CPTO \(ftpPath(destPath!))"
+        case .move: command = "RNFR \(ftpPath(sourcePath))\r\nRNTO \(ftpPath(destPath!))"
+        case .remove: command = "DELE \(ftpPath(sourcePath))"
+        case .link: command = "SITE SYMLINK \(ftpPath(sourcePath)) \(ftpPath(destPath!))"
+        default: return nil // modify, fetch
+        }
+        let progress = Progress(totalUnitCount: 1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.fpstreamTask(withHostName: baseURL!.host!, port: baseURL!.port!)
+        self.ftpLogin(task) { (error) in
+            if let error = error {
+                completionHandler?(error)
+                self.delegateNotify(operation, error: error)
+                return
+            }
+            
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                if let error = error {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                    return
+                }
+                
+                guard let response = response else {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: self.urlError(sourcePath, code: .badServerResponse))
+                    return
+                }
+                
+                let codes: [Int] = response.components(separatedBy: .newlines).flatMap({ $0.isEmpty ? nil : $0})
+                    .flatMap {
+                        let code = $0.components(separatedBy: .whitespaces).flatMap({ $0.isEmpty ? nil : $0}).first
+                        return code != nil ? Int(code!) : nil
+                }
+                
+                if codes.filter({ (450..<560).contains($0) }).count > 0 {
+                    let errorCode: URLError.Code
+                    switch operation {
+                    case .create: errorCode = .cannotCreateFile
+                    case .modify: errorCode = .cannotWriteToFile
+                    case .copy:
+                        self.fallbackCopy(operation, progress: progress, completionHandler: completionHandler)
+                        return
+                    case .move: errorCode = .cannotMoveFile
+                    case .remove:
+                        self.fallbackRemove(operation, progress: progress, on: task, completionHandler: completionHandler)
+                        return
+                    case .link: errorCode = .cannotWriteToFile
+                    default: errorCode = .cannotOpenFile
+                    }
+                    let error = self.urlError(sourcePath, code: errorCode)
+                    progress.cancel()
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                    return
+                }
+                
+                progress.completedUnitCount = progress.totalUnitCount
+                completionHandler?(nil)
+                self.delegateNotify(operation)
+            })
+        }
+        
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        return progress
+    }
+    
+    private func fallbackCopy(_ operation: FileOperationType, progress: Progress, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = operation.source
+        guard let destPath = operation.destination else { return }
+        
+        let localURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
+        
+        progress.becomeCurrent(withPendingUnitCount: 1)
+        _ = self.copyItem(path: sourcePath, toLocalURL: localURL) { (error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                return
+            }
+            
+            progress.becomeCurrent(withPendingUnitCount: 1)
+            _ = self.copyItem(localFile: localURL, to: destPath) { error in
+                completionHandler?(nil)
+                self.delegateNotify(operation)
+            }
+            progress.resignCurrent()
+        }
+        progress.resignCurrent()
+        return
+    }
+    
+    private func fallbackRemove(_ operation: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = operation.source
+        
+        self.execute(command: "SITE RMDIR \(ftpPath(sourcePath))", on: task) { (response, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let response = response else {
+                    throw  self.urlError(sourcePath, code: .badServerResponse)
+                }
+                
+                if response.hasPrefix("50") {
+                    self.fallbackRecursiveRemove(operation, progress: progress, on: task, completionHandler: completionHandler)
+                    return
+                }
+                
+                if !response.hasPrefix("2") {
+                    throw self.urlError(sourcePath, code: .cannotRemoveFile)
+                }
+                self.dispatch_queue.async {
+                    completionHandler?(nil)
+                }
+                self.delegateNotify(operation)
+            } catch {
+                progress.cancel()
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                }
+                self.delegateNotify(operation, error: error)
+            }
+        }
+    }
+    
+    private func fallbackRecursiveRemove(_ operation: FileOperationType, progress: Progress, on task: FileProviderStreamTask, completionHandler: SimpleCompletionHandler) {
+        let sourcePath = operation.source
+        
+        _ = self.recursiveList(path: sourcePath, useMLST: true, completionHandler: { (contents, error) in
+            if let error = error {
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                return
+            }
+            
+            progress.becomeCurrent(withPendingUnitCount: 1)
+            let recursiveProgress = Progress(totalUnitCount: Int64(contents.count))
+            let sortedContents = contents.sorted(by: {
+                $0.path.localizedStandardCompare($1.path) == .orderedDescending
+            })
+            progress.resignCurrent()
+            var command = ""
+            for file in sortedContents {
+                command += (file.isDirectory ? "RMD \(self.ftpPath(file.path))" : "DELE \(self.ftpPath(file.path))") + "\r\n"
+            }
+            command += "RMD \(self.ftpPath(sourcePath))"
+            
+            self.execute(command: command, on: task, completionHandler: { (response, error) in
+                recursiveProgress.completedUnitCount += 1
+                self.dispatch_queue.async {
+                    completionHandler?(error)
+                    self.delegateNotify(operation, error: error)
+                }
+                // TODO: Digest response
+            })
+        })
+    }
+}
+
+extension FTPFileProvider: FileProvider { }
@@ -0,0 +1,957 @@
+//
+//  FTPHelper.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+internal extension FTPFileProvider {
+    func readDataUntilEOF(of task: FileProviderStreamTask, minLength: Int, receivedData: Data? = nil, timeout: TimeInterval, completionHandler: @escaping (_ data: Data?, _ errror:Error?) -> Void) {
+        task.readData(ofMinLength: minLength, maxLength: 65535, timeout: timeout) { (data, eof, error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            
+            var receivedData = receivedData
+            if let data = data {
+                if receivedData != nil {
+                    receivedData!.append(data)
+                } else {
+                    receivedData = data
+                }
+            }
+            
+            if eof {
+                completionHandler(receivedData, nil)
+            } else {
+                self.readDataUntilEOF(of: task, minLength: 0, receivedData: receivedData, timeout: timeout, completionHandler: completionHandler)
+            }
+            
+        }
+    }
+    
+    func execute(command: String, on task: FileProviderStreamTask, minLength: Int = 4, afterSend: ((_ error: Error?) -> Void)? = nil, completionHandler: @escaping (_ response: String?, _ error: Error?) -> Void) {
+        let timeout = session.configuration.timeoutIntervalForRequest
+        let terminalcommand = command + "\r\n"
+        task.write(terminalcommand.data(using: .utf8)!, timeout: timeout) { (error) in
+            if let error = error {
+                completionHandler(nil, error)
+                return
+            }
+            afterSend?(error)
+            
+            if task.state == .suspended {
+                task.resume()
+            }
+            
+            task.readData(ofMinLength: minLength, maxLength: 1024, timeout: timeout) { (data, eof, error) in
+                if let error = error {
+                    completionHandler(nil, error)
+                    return
+                }
+                
+                if let data = data, let response = String(data: data, encoding: .utf8) {
+                    completionHandler(response.trimmingCharacters(in: .whitespacesAndNewlines), nil)
+                } else {
+                    completionHandler(nil, self.urlError("", code: .cannotParseResponse))
+                    return
+                }
+            }
+        }
+    }
+    
+    func ftpLogin(_ task: FileProviderStreamTask, completionHandler: @escaping (_ error: Error?) -> Void) {
+        let timeout = session.configuration.timeoutIntervalForRequest
+        if task.state == .suspended {
+            task.resume()
+        }
+        
+        var isSecure = false
+        // Implicit FTP Connection
+        if self.baseURL?.port == 990 || self.baseURL?.scheme == "ftps" {
+            task.startSecureConnection()
+            isSecure = true
+        }
+        
+        let credential = self.credential
+        
+        task.readData(ofMinLength: 4, maxLength: 2048, timeout: timeout) { (data, eof, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let data = data, let response = String(data: data, encoding: .utf8) else {
+                    throw self.urlError("", code: .cannotParseResponse)
+                }
+                
+                guard response.hasPrefix("22") else {
+                    throw FileProviderFTPError(message: response)
+                }
+            } catch {
+                completionHandler(error)
+                return
+            }
+            
+            let loginHandle: () -> Void = {
+                self.execute(command: "USER \(credential?.user ?? "anonymous")", on: task) { (response, error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    
+                    guard let response = response else {
+                        completionHandler(self.urlError("", code: .badServerResponse))
+                        return
+                    }
+                    
+                    // successfully logged in
+                    if response.hasPrefix("23") {
+                        completionHandler(nil)
+                        return
+                    }
+                    
+                    // needs password
+                    if FileProviderFTPError(message: response).code == 331 {
+                        self.execute(command: "PASS \(credential?.password ?? "fileprovider@")", on: task) { (response, error) in
+                            if response?.hasPrefix("23") ?? false {
+                                completionHandler(nil)
+                            } else {
+                                completionHandler(self.urlError("", code: .userAuthenticationRequired))
+                            }
+                        }
+                        return
+                    }
+                    
+                    let error = FileProviderFTPError(message: response)
+                    completionHandler(error)
+                }
+            }
+            
+            if !isSecure && self.baseURL?.scheme == "ftpes" {
+                // Explicit FTP Connection, by upgrading connection to FTP/SSL
+                self.execute(command: "AUTH TLS", on: task, minLength: 0, completionHandler: { (response, error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    
+                    if let response = response, response.hasPrefix("23") {
+                        task.startSecureConnection()
+                        isSecure = true
+                        self.execute(command: "PBSZ 0\r\nPROT P", on: task, completionHandler: { (response, error) in
+                            if let error = error {
+                                completionHandler(error)
+                                return
+                            }
+                            
+                            loginHandle()
+                        })
+                    }
+                })
+            } else if isSecure {
+                self.execute(command: "PBSZ 0\r\nPROT P", on: task, completionHandler: { (response, error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    
+                    loginHandle()
+                })
+            } else {
+                loginHandle()
+            }
+        }
+    }
+    
+    func ftpCwd(_ task: FileProviderStreamTask, to path: String, completionHandler: @escaping (_ error: Error?) -> Void) {
+        self.execute(command: "CWD \(path)", on: task) { (response, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let response = response else {
+                    throw self.urlError(path, code: .badServerResponse)
+                }
+                
+                // successfully logged in
+                if response.hasPrefix("25") {
+                    completionHandler(nil)
+                }
+                    // not logged in
+                else if response.hasPrefix("55") {
+                    throw FileProviderFTPError(message: response)
+                }
+            } catch {
+                completionHandler(error)
+            }
+        }
+    }
+    
+    func ftpPassive(_ task: FileProviderStreamTask, completionHandler: @escaping (_ dataTask: FileProviderStreamTask?, _ error: Error?) -> Void) {
+        func trimmedNumber(_ s : String) -> String {
+            return s.components(separatedBy: CharacterSet.decimalDigits.inverted).joined()
+        }
+        
+        self.execute(command: "PASV", on: task) { (response, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let response = response, let destString = response.components(separatedBy: " ").flatMap({ $0 }).last.flatMap(String.init) else {
+                    throw self.urlError("", code: .badServerResponse)
+                }
+                
+                let destArray = destString.components(separatedBy: ",").flatMap({ UInt32(trimmedNumber($0)) })
+                guard destArray.count == 6 else {
+                    throw self.urlError("", code: .badServerResponse)
+                }
+                
+                // first 4 elements are ip, 2 next are port, as byte
+                var host = destArray.prefix(4).flatMap(String.init).joined(separator: ".")
+                let portHi = Int(destArray[4]) << 8
+                let portLo = Int(destArray[5])
+                let port = portHi + portLo
+                // IPv6 workaround
+                if host == "127.555.555.555" {
+                    host = self.baseURL!.host!
+                }
+                
+                let passiveTask = self.session.fpstreamTask(withHostName: host, port: port)
+                passiveTask.resume()
+                if self.baseURL?.scheme == "ftps" || self.baseURL?.scheme == "ftpes" || self.baseURL?.port == 990 {
+                    passiveTask.startSecureConnection()
+                }
+                completionHandler(passiveTask, nil)
+            } catch {
+                completionHandler(nil, error)
+                return
+            }
+            
+        }
+    }
+    
+    func ftpActive(_ task: FileProviderStreamTask, completionHandler: @escaping (_ dataTask: FileProviderStreamTask?, _ error: Error?) -> Void) {
+        let service = NetService(domain: "", type: "_tcp.", name: "", port: 0)
+        service.publish(options: .listenForConnections)
+        let startTime = Date()
+        while service.port < 1 && startTime.timeIntervalSinceNow > -self.session.configuration.timeoutIntervalForRequest {
+            usleep(100_000)
+        }
+        let activeTask = self.session.fpstreamTask(withNetService: service)
+        activeTask.resume()
+        if self.baseURL?.scheme == "ftps" || self.baseURL?.port == 990 {
+            activeTask.startSecureConnection()
+        }
+        
+        self.execute(command: "PORT \(service.port)", on: task) { (response, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let response = response else {
+                    throw self.urlError("", code: .badServerResponse)
+                }
+                
+                guard !response.hasPrefix("5") else {
+                    throw self.urlError("", code: .cannotConnectToHost)
+                }
+                
+                completionHandler(activeTask, nil)
+            } catch {
+                activeTask.cancel()
+                completionHandler(nil, error)
+            }
+        }
+    }
+    
+    func ftpDataConnect(_ task: FileProviderStreamTask, completionHandler: @escaping (_ dataTask: FileProviderStreamTask?, _ error: Error?) -> Void) {
+        if self.passiveMode {
+            self.ftpPassive(task, completionHandler: completionHandler)
+        } else {
+            dispatch_queue.async {
+                self.ftpActive(task, completionHandler: completionHandler)
+            }
+        }
+    }
+    
+    func ftpRest(_ task: FileProviderStreamTask, startPosition: Int64, completionHandler: @escaping (_ error: Error?) -> Void) {
+        self.execute(command: "REST \(startPosition)", on: task) { (response, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                // Successful
+                guard let response = response else {
+                    throw self.urlError("", code: .badServerResponse)
+                }
+                
+                if response.hasPrefix("35") {
+                    completionHandler(nil)
+                } else {
+                    throw FileProviderFTPError(message: response, path: "")
+                }
+            } catch {
+                completionHandler(error)
+            }
+            
+        }
+    }
+    
+    func ftpList(_ task: FileProviderStreamTask, of path: String, useMLST: Bool, completionHandler: @escaping (_ contents: [String], _ error: Error?) -> Void) {
+        self.ftpDataConnect(task) { (dataTask, error) in
+            if let error = error {
+                completionHandler([], error)
+                return
+            }
+            
+            guard let dataTask = dataTask else {
+                completionHandler([], self.urlError(path, code: .badServerResponse))
+                return
+            }
+            
+            var success = false
+            let command = useMLST ? "MLSD \(path)" : "LIST \(path)"
+            self.execute(command: command, on: task, minLength: 20, afterSend: { error in
+                // starting passive task
+                let timeout = self.session.configuration.timeoutIntervalForRequest
+                
+                DispatchQueue.global().async {
+                    var finalData = Data()
+                    var eof = false
+                    var error: Error?
+                    
+                    do {
+                        while !eof {
+                            let group = DispatchGroup()
+                            group.enter()
+                            dataTask.readData(ofMinLength: 1, maxLength: 65535, timeout: timeout, completionHandler: { (data, seof, serror) in
+                                if let data = data {
+                                    finalData.append(data)
+                                }
+                                eof = seof
+                                error = serror
+                                group.leave()
+                            })
+                            let waitResult = group.wait(timeout: .now() + timeout)
+                            
+                            if let error = error {
+                                if !((error as NSError).domain == URLError.errorDomain && (error as NSError).code == URLError.cancelled.rawValue) {
+                                    throw error
+                                }
+                                return
+                            }
+                            
+                            if waitResult == .timedOut {
+                                throw self.urlError(path, code: .timedOut)
+                            }
+                        }
+                        
+                        guard let response = String(data: finalData, encoding: .utf8) else {
+                            throw self.urlError(path, code: .badServerResponse)
+                        }
+                        
+                        let contents: [String] = response.components(separatedBy: "\n").flatMap({ $0.trimmingCharacters(in: .whitespacesAndNewlines) })
+                        success = true
+                        completionHandler(contents, nil)
+                    } catch {
+                        completionHandler([], error)
+                    }
+                }
+            }) { (response, error) in
+                do {
+                    if let error = error {
+                        throw error
+                    }
+                    
+                    guard let response = response else {
+                        throw self.urlError(path, code: .cannotParseResponse)
+                    }
+                    
+                    if response.hasPrefix("500") && useMLST {
+                        dataTask.cancel()
+                        self.serverSupportsRFC3659 = false
+                        throw self.urlError(path, code: .unsupportedURL)
+                    }
+                    
+                    if !success && !(response.hasPrefix("25") || response.hasPrefix("15")) {
+                        throw FileProviderFTPError(message: response, path: path)
+                    }
+                } catch {
+                    self.dispatch_queue.async {
+                        completionHandler([], error)
+                    }
+                }
+            }
+        }
+    }
+    
+    func recursiveList(path: String, useMLST: Bool, foundItemsHandler: ((_ contents: [FileObject]) -> Void)? = nil, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let progress = Progress(totalUnitCount: -1)
+        let queue = DispatchQueue(label: "\(self.type).recursiveList")
+        queue.async {
+            let group = DispatchGroup()
+            var result = [FileObject]()
+            var success = true
+            group.enter()
+            self.contentsOfDirectory(path: path, completionHandler: { (files, error) in
+                success = success && (error == nil)
+                if let error = error {
+                    completionHandler([], error)
+                    group.leave()
+                    return
+                }
+                
+                result.append(contentsOf: files)
+                progress.completedUnitCount = Int64(files.count)
+                foundItemsHandler?(files)
+                
+                let directories: [FileObject] = files.filter { $0.isDirectory }
+                progress.becomeCurrent(withPendingUnitCount: Int64(directories.count))
+                for dir in directories {
+                    group.enter()
+                    _=self.recursiveList(path: dir.path, useMLST: useMLST, foundItemsHandler: foundItemsHandler, completionHandler: { (contents, error) in
+                        success = success && (error == nil)
+                        if let error = error {
+                            completionHandler([], error)
+                            group.leave()
+                            return
+                        }
+                        
+                        foundItemsHandler?(files)
+                        result.append(contentsOf: contents)
+                        
+                        group.leave()
+                    })
+                }
+                progress.resignCurrent()
+                group.leave()
+            })
+            group.wait()
+            
+            if success {
+                self.dispatch_queue.async {
+                    completionHandler(result, nil)
+                }
+            }
+        }
+        return progress
+    }
+    
+    func ftpRetrieveData(_ task: FileProviderStreamTask, filePath: String, from position: Int64 = 0, length: Int = -1, onTask: ((_ task: FileProviderStreamTask) -> Void)?, onProgress: ((_ bytesReceived: Int64, _ totalReceived: Int64, _ expectedBytes: Int64) -> Void)?, completionHandler: @escaping (_ data: Data?, _ error: Error?) -> Void) {
+        
+        // Check cache
+        if useCache, let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL, let cachedResponse = self.cache?.cachedResponse(for: URLRequest(url: url)), cachedResponse.data.count > 0 {
+            dispatch_queue.async {
+                completionHandler(cachedResponse.data, nil)
+            }
+            return
+        }
+        
+        self.attributesOfItem(path: filePath) { (file, error) in
+            let totalSize = file?.size ?? -1
+            // Retreive data from server
+            self.ftpDataConnect(task) { (dataTask, error) in
+                if let error = error {
+                    completionHandler(nil, error)
+                    return
+                }
+                
+                guard let dataTask = dataTask else {
+                    completionHandler(nil, self.urlError(filePath, code: .badServerResponse))
+                    return
+                }
+                
+                // Send retreive command
+                let len = 19 /* TYPE response */ + 65 + String(position).count /* REST Response */ + 53 + filePath.count + String(totalSize).count /* RETR open response */ + 26 /* RETR Transfer complete message. */
+                self.execute(command: "TYPE I" + "\r\n" + "REST \(position)" + "\r\n" + "RETR \(filePath)", on: task, minLength: len, afterSend: { error in
+                    // starting passive task
+                    onTask?(dataTask)
+                    
+                    let timeout = self.session.configuration.timeoutIntervalForRequest
+                    DispatchQueue.global().async {
+                        var finalData = Data()
+                        var eof = false
+                        var error: Error?
+                        while !eof {
+                            let group = DispatchGroup()
+                            group.enter()
+                            dataTask.readData(ofMinLength: 0, maxLength: 65535, timeout: timeout, completionHandler: { (data, seof, serror) in
+                                if let data = data {
+                                    finalData.append(data)
+                                    onProgress?(Int64(data.count), Int64(finalData.count), totalSize)
+                                }
+                                eof = seof || (length > 0 && finalData.count >= length)
+                                if length > 0 && finalData.count > length {
+                                    finalData.count = length
+                                }
+                                error = serror
+                                group.leave()
+                            })
+                            let waitResult = group.wait(timeout: .now() + timeout)
+                            
+                            if let error = error {
+                                completionHandler(nil, error)
+                                return
+                            }
+                            
+                            if waitResult == .timedOut {
+                                completionHandler(nil, self.urlError(filePath, code: .timedOut))
+                                return
+                            }
+                        }
+                        
+                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL {
+                            let urlresponse = URLResponse(url: url, mimeType: nil, expectedContentLength: finalData.count, textEncodingName: nil)
+                            let cachedResponse = CachedURLResponse(response: urlresponse, data: finalData)
+                            let request = URLRequest(url: url)
+                            self.cache?.storeCachedResponse(cachedResponse, for: request)
+                        }
+                        
+                        completionHandler(finalData, nil)
+                        return
+                    }
+                }) { (response, error) in
+                    do {
+                        if let error = error {
+                            throw error
+                        }
+                        
+                        guard let response = response else {
+                            throw self.urlError(filePath, code: .cannotParseResponse)
+                        }
+                        
+                        if !(response.hasPrefix("1") || !response.hasPrefix("2")) {
+                            throw FileProviderFTPError(message: response)
+                        }
+                    } catch {
+                        self.dispatch_queue.async {
+                            completionHandler(nil, error)
+                        }
+                    }
+                }
+            }
+        }
+    }
+    
+    func ftpRetrieveFile(_ task: FileProviderStreamTask, filePath: String, from position: Int64 = 0, length: Int = -1, onTask: ((_ task: FileProviderStreamTask) -> Void)?, onProgress: ((_ bytesReceived: Int64, _ totalReceived: Int64, _ expectedBytes: Int64) -> Void)?, completionHandler: @escaping (_ file: URL?, _ error: Error?) -> Void) {
+        let tempURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString).appendingPathExtension("tmp")
+        
+        // Check cache
+        if useCache, let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL, let cachedResponse = self.cache?.cachedResponse(for: URLRequest(url: url)), cachedResponse.data.count > 0 {
+            dispatch_queue.async {
+                do {
+                    try cachedResponse.data.write(to: tempURL)
+                    completionHandler(tempURL, nil)
+                } catch {
+                    completionHandler(nil, error)
+                }
+                try? FileManager.default.removeItem(at: tempURL)
+            }
+            return
+        }
+        
+        self.attributesOfItem(path: filePath) { (file, error) in
+            let totalSize = file?.size ?? -1
+            // Retreive data from server
+            self.ftpDataConnect(task) { (dataTask, error) in
+                if let error = error {
+                    completionHandler(nil, error)
+                    return
+                }
+                
+                guard let dataTask = dataTask else {
+                    completionHandler(nil, self.urlError(filePath, code: .badServerResponse))
+                    return
+                }
+                
+                // Send retreive command
+                let len = 19 /* TYPE response */ + 65 + String(position).count /* REST Response */ + 53 + filePath.count + String(totalSize).count /* RETR open response */ + 26 /* RETR Transfer complete message. */
+                self.execute(command: "TYPE I"  + "\r\n" + "REST \(position)" + "\r\n" + "RETR \(filePath)", on: task, minLength: len, afterSend: { error in
+                    // starting passive task
+                    onTask?(dataTask)
+                    
+                    let timeout = self.session.configuration.timeoutIntervalForRequest
+                    DispatchQueue.global().async {
+                        var finalData = Data()
+                        var eof = false
+                        var error: Error?
+                        while !eof {
+                            let group = DispatchGroup()
+                            group.enter()
+                            dataTask.readData(ofMinLength: 0, maxLength: 65535, timeout: timeout, completionHandler: { (data, seof, serror) in
+                                if let data = data {
+                                    finalData.append(data)
+                                    onProgress?(Int64(data.count), Int64(finalData.count), totalSize)
+                                }
+                                eof = seof || (length > 0 && finalData.count >= length)
+                                if length > 0 && finalData.count > length {
+                                    finalData.count = length
+                                }
+                                error = serror
+                                group.leave()
+                            })
+                            let waitResult = group.wait(timeout: .now() + timeout)
+                            
+                            if let error = error {
+                                completionHandler(nil, error)
+                                return
+                            }
+                            
+                            if waitResult == .timedOut {
+                                error = self.urlError("", code: .timedOut)
+                                completionHandler(nil, error)
+                                return
+                            }
+                        }
+                        
+                        if let url = URL(string: filePath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? filePath, relativeTo: self.baseURL!)?.absoluteURL {
+                            let urlresponse = URLResponse(url: url, mimeType: nil, expectedContentLength: finalData.count, textEncodingName: nil)
+                            let cachedResponse = CachedURLResponse(response: urlresponse, data: finalData)
+                            let request = URLRequest(url: url)
+                            self.cache?.storeCachedResponse(cachedResponse, for: request)
+                        }
+                        
+                        self.dispatch_queue.async {
+                            do {
+                                try finalData.write(to: tempURL)
+                                completionHandler(tempURL, nil)
+                                // Removing temporary file after coordinating
+                                NSFileCoordinator().coordinate(writingItemAt: tempURL, options: .forDeleting, error: nil, byAccessor: { (tempURL) in
+                                    try? FileManager.default.removeItem(at: tempURL)
+                                })
+                            } catch {
+                                completionHandler(nil, error)
+                            }
+                        }
+                    }
+                }) { (response, error) in
+                    do {
+                        if let error = error {
+                            throw error
+                        }
+                        
+                        guard let response = response else {
+                            throw self.urlError(filePath, code: .cannotParseResponse)
+                        }
+                        
+                        if !(response.hasPrefix("1") || response.hasPrefix("2")) {
+                            throw FileProviderFTPError(message: response)
+                        }
+                    } catch {
+                        self.dispatch_queue.async {
+                            completionHandler(nil, error)
+                        }
+                    }
+                }
+            }
+        }
+    }
+    
+    func ftpStore(_ task: FileProviderStreamTask, filePath: String, fromData: Data?, fromFile: URL?, onTask: ((_ task: FileProviderStreamTask) -> Void)?,  onProgress: ((_ bytesSent: Int64, _ totalSent: Int64, _ expectedBytes: Int64) -> Void)?, completionHandler: @escaping (_ error: Error?) -> Void) {
+        let timeout = self.session.configuration.timeoutIntervalForRequest
+        operation_queue.addOperation {
+            guard let size: Int64 = (fromData != nil ? Int64(fromData!.count) : nil) ?? fromFile?.fileSize else { return }
+            
+            var error: Error?
+            let chunkSize: Int
+            switch size {
+            case 0..<262_144: chunkSize = 32_768 // 0KB To 256KB, chunk size is 32KB
+            case 262_144..<1_048_576: chunkSize = 65_536 // 256KB To 1MB, chunk size is 64KB
+            case 1_048_576..<10_485_760: chunkSize = 131_072 // 1MB To 10MB, chunk size is 128KB
+            case 10_048_576..<33_554_432: chunkSize = 262_144 // 10MB To 32MB, chunk size is 256KB
+            default: chunkSize = 524_288 // Larger than 32MB, chunk size is 512KB
+            }
+            
+            var fileHandle: FileHandle?
+            if let file = fromFile {
+                fileHandle = FileHandle(forReadingAtPath: file.path)
+            }
+            defer {
+                fileHandle?.closeFile()
+            }
+            
+            var eof = false
+            var sent: Int64 = 0
+            
+            while !eof {
+                let subdata: Data
+                if let data = fromData {
+                    let endIndex = min(data.count, Int(sent) + chunkSize)
+                    eof = endIndex == data.count
+                    subdata = data.subdata(in: Int(sent)..<endIndex)
+                }else if let fileHandle = fileHandle {
+                    subdata = fileHandle.readData(ofLength: chunkSize)
+                    eof = Int64(fileHandle.offsetInFile) == size
+                } else {
+                    return
+                }
+                if subdata.count == 0 { continue }
+                
+                let group = DispatchGroup()
+                group.enter()
+                self.ftpStore(task, data: subdata, to: filePath, from: sent, onTask: onTask, completionHandler: { (serror) in
+                    error = serror
+                    sent += Int64(subdata.count)
+                    group.leave()
+                    onProgress?(Int64(subdata.count), sent, size)
+                })
+                let waitResult = group.wait(timeout: .now() + timeout)
+                
+                if let error = error {
+                    completionHandler(error)
+                    return
+                }
+                
+                if waitResult == .timedOut {
+                    error = self.urlError(filePath, code: .timedOut)
+                    completionHandler(error)
+                    return
+                }
+            }
+            completionHandler(nil)
+        }
+    }
+    
+    func ftpStore(_ task: FileProviderStreamTask, data: Data, to filePath: String, from position: Int64, onTask: ((_ task: FileProviderStreamTask) -> Void)?, completionHandler: @escaping (_ error: Error?) -> Void) {
+        self.ftpDataConnect(task) { (dataTask, error) in
+            if let error = error {
+                completionHandler(error)
+                return
+            }
+            
+            guard let dataTask = dataTask else {
+                completionHandler(self.urlError(filePath, code: .badServerResponse))
+                return
+            }
+            
+            // Send retreive command
+            var success = false
+            let len = 19 /* TYPE response */ + 65 + String(position).count /* REST Response */ + 44 + filePath.count /* STOR open response */ + 10 /* RETR Transfer complete message. */
+            self.execute(command: "TYPE I"  + "\r\n" + "REST \(position)"  + "\r\n" + "STOR \(filePath)", on: task, minLength: len, afterSend: { error in
+                // starting passive task
+                let timeout = self.session.configuration.timeoutIntervalForRequest
+                onTask?(dataTask)
+                
+                if data.count == 0 { return }
+                
+                dataTask.write(data, timeout: timeout, completionHandler: { (error) in
+                    if let error = error {
+                        completionHandler(error)
+                        return
+                    }
+                    success = true
+                    
+                    dataTask.closeRead()
+                    dataTask.closeWrite()
+                })
+            }) { (response, error) in
+                guard success else { return }
+                
+                do {
+                    if let error = error {
+                        throw error
+                    }
+                    
+                    guard let response = response else {
+                        throw self.urlError(filePath, code: .cannotParseResponse)
+                    }
+                    
+                    if !(response.hasPrefix("1") || response.hasPrefix("2")) {
+                        throw FileProviderFTPError(message: response)
+                    }
+                    
+                    completionHandler(nil)
+                } catch {
+                    self.dispatch_queue.async {
+                        completionHandler(error)
+                    }
+                }
+            }
+        }
+    }
+    
+    func ftpQuit(_ task: FileProviderStreamTask) {
+        self.execute(command: "QUIT", on: task) { (_, _) in
+            //task.closeRead()
+            //task.closeWrite()
+        }
+    }
+    
+    func ftpPath(_ apath: String) -> String {
+        // path of base url should be concreted into file path! And remove final slash
+        var path = baseURL!.appendingPathComponent(apath).path.replacingOccurrences(of: "/", with: "", options: [.anchored, .backwards])
+        
+        // Fixing slashes
+        if !path.hasPrefix("/") {
+            path = "/" + path
+        }
+        
+        return path
+    }
+    
+    func parseUnixList(_ text: String, in path: String) -> FileObject? {
+        let gregorian = Calendar(identifier: .gregorian)
+        let nearDateFormatter = DateFormatter()
+        nearDateFormatter.calendar = gregorian
+        nearDateFormatter.locale = Locale(identifier: "en_US_POSIX")
+        nearDateFormatter.dateFormat = "MMM dd hh:ss yyyy"
+        let farDateFormatter = DateFormatter()
+        farDateFormatter.calendar = gregorian
+        farDateFormatter.locale = Locale(identifier: "en_US_POSIX")
+        farDateFormatter.dateFormat = "MMM dd yyyy"
+        let thisYear = gregorian.component(.year, from: Date())
+        
+        let components = text.components(separatedBy: " ").flatMap { $0.isEmpty ? nil : $0 }
+        guard components.count >= 9 else { return nil }
+        let posixPermission = components[0]
+        let linksCount = Int(components[1]) ?? 0
+        //let owner = components[2]
+        //let groupOwner = components[3]
+        let size = Int64(components[4]) ?? -1
+        let date = components[5..<8].joined(separator: " ")
+        let name = components[8..<components.count].joined(separator: " ")
+        
+        guard name != "." && name != ".." else { return nil }
+        let path = (path as NSString).appendingPathComponent(name).replacingOccurrences(of: "/", with: "", options: .anchored)
+        
+        let file = FileObject(url: url(of: path), name: name, path: path)
+        #if swift(>=4.0)
+        let typeChar = posixPermission.first ?? Character(" ")
+        #else
+        let typeChar = posixPermission.characters.first ?? Character(" ")
+        #endif
+        switch String(typeChar) {
+        case "d": file.type = .directory
+        case "l": file.type = .symbolicLink
+        default:  file.type = .regular
+        }
+        file.isReadOnly = !posixPermission.contains("w")
+        file.size = file.isDirectory ? -1 : size
+        file.allValues[.linkCountKey] = linksCount
+        
+        if let parsedDate = nearDateFormatter.date(from: date + " " + String(thisYear)) {
+            if parsedDate > Date() {
+                file.modifiedDate = gregorian.date(byAdding: .year, value: -1, to: parsedDate)
+            } else {
+                file.modifiedDate = parsedDate
+            }
+        } else if let parsedDate = farDateFormatter.date(from: date) {
+            file.modifiedDate = parsedDate
+        }
+        
+        return file
+    }
+    
+    func parseMLST(_ text: String, in path: String) -> FileObject? {
+        var components = text.components(separatedBy: ";").flatMap { $0.isEmpty ? nil : $0 }
+        guard components.count > 1 else { return nil }
+        
+        let nameOrPath = components.removeLast().trimmingCharacters(in: .whitespacesAndNewlines)
+        var correctedPath: String
+        let name: String
+        if nameOrPath.hasPrefix("/") {
+            correctedPath = nameOrPath.replacingOccurrences(of: baseURL!.path, with: "", options: .anchored)
+            name = (nameOrPath as NSString).lastPathComponent
+        } else {
+            name = nameOrPath
+            correctedPath = (path as NSString).appendingPathComponent(nameOrPath)
+        }
+        correctedPath = correctedPath.replacingOccurrences(of: "/", with: "", options: .anchored)
+        
+        var attributes = [String: String]()
+        for component in components {
+            let keyValue = component.components(separatedBy: "=") .flatMap { $0.isEmpty ? nil : $0 }
+            guard keyValue.count >= 2, !keyValue[0].isEmpty else { continue }
+            attributes[keyValue[0].lowercased()] = keyValue.dropFirst().joined(separator: "=")
+        }
+        
+        let file = FileObject(url: url(of: correctedPath), name: name, path: correctedPath)
+        let dateFormatter = DateFormatter()
+        dateFormatter.calendar = Calendar(identifier: .gregorian)
+        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
+        dateFormatter.dateFormat = "yyyyMMddhhmmss"
+        for (key, attribute) in attributes {
+            switch key {
+            case "type":
+                switch attribute.lowercased() {
+                case "file": file.type = .regular
+                case "dir": file.type = .directory
+                case "link": file.type = .symbolicLink
+                case "os.unix=block": file.type = .blockSpecial
+                case "cdir", "pdir": return nil // . and .. files are redundant in listing
+                default: file.type = .unknown
+                }
+                
+            case "unique":
+                file.allValues[.fileResourceIdentifierKey] = attribute
+                
+            case "modify":
+                file.modifiedDate = dateFormatter.date(from: attribute)
+            
+            case "create":
+                file.creationDate = dateFormatter.date(from: attribute)
+                
+            case "perm":
+                file.allValues[.isReadableKey] = attribute.contains("r") || attribute.contains("l")
+                file.allValues[.isWritableKey] = attribute.contains("w") || attribute.contains("a")
+                
+            case "size":
+                file.size = Int64(attribute) ?? -1
+                
+            case "media-type":
+                file.allValues[.mimeTypeKey] = attribute
+                
+            default:
+                break
+            }
+        }
+        
+        return file
+    }
+}
+
+/// Contains error code and description returned by FTP/S provider.
+public struct FileProviderFTPError: Error {
+    /// HTTP status code returned for error by server.
+    public let code: Int
+    /// Path of file/folder casued that error
+    public let path: String
+    /// Contents returned by server as error description
+    public let errorDescription: String?
+    
+    init(code: Int, path: String, errorDescription: String?) {
+        self.code = code
+        self.path = path
+        self.errorDescription = errorDescription
+    }
+    
+    init(message response: String, path: String = "") {
+        let message = response.components(separatedBy: .newlines).last ?? "No Response"
+        #if swift(>=4.0)
+        let startIndex = (message.index(of: "-") ?? message.index(of: " ")) ?? message.startIndex
+        self.code = Int(message[..<startIndex].trimmingCharacters(in: .whitespacesAndNewlines)) ?? -1
+        #else
+        let startIndex = (message.characters.index(of: "-") ?? message.characters.index(of: " ")) ?? message.startIndex
+        self.code = Int(message.substring(to: startIndex).trimmingCharacters(in: .whitespacesAndNewlines)) ?? -1
+        #endif
+        self.path = path
+        if code > 0 {
+            #if swift(>=4.0)
+            self.errorDescription = message[startIndex...].trimmingCharacters(in: .whitespacesAndNewlines)
+            #else
+            self.errorDescription = message.substring(from: startIndex).trimmingCharacters(in: .whitespacesAndNewlines)
+            #endif
+        } else {
+            self.errorDescription = message
+        }
+    }
+}
@@ -13,31 +13,32 @@ open class FileObject: Equatable {
    /// A `Dictionary` contains file information,  using `URLResourceKey` keys.
    open internal(set) var allValues: [URLResourceKey: Any]
    
-    internal init(allValues: [URLResourceKey: Any]) {
+    public init(allValues: [URLResourceKey: Any]) {
        self.allValues = allValues
    }
    
-    internal init(url: URL, name: String, path: String) {
+    internal init(url: URL?, name: String, path: String) {
        self.allValues = [URLResourceKey: Any]()
-        self.url = url
+        if let url = url {
+            self.url = url
+        }
        self.name = name
        self.path = path
    }
    
-    /// url to access the resource, not supported by Dropbox provider
-    @available(*, deprecated, renamed: "url", message: "Use url.absoluteURL instead.")
-    open var absoluteURL: URL? {
-        return url?.absoluteURL
-    }
-    
    /// URL to access the resource, can be a relative URL against base URL.
    /// not supported by Dropbox provider.
-    open internal(set) var url: URL? {
+    open internal(set) var url: URL {
        get {
-            return allValues[.fileURL] as? URL
+            if let url = allValues[.fileURLKey] as? URL {
+                return url
+            } else {
+                let path = self.path.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? self.path
+                return URL(string: path) ?? URL(string: "/")!
+            }
        }
        set {
-            allValues[.fileURL] = newValue
+            allValues[.fileURLKey] = newValue
        }
    }
    
@@ -71,6 +72,16 @@ open class FileObject: Equatable {
        }
    }
    
+    /// Count of children items of a driectory.
+    open internal(set) var childrensCount: Int? {
+        get {
+            return allValues[.childrensCount] as? Int
+        }
+        set {
+            allValues[.childrensCount] = newValue
+        }
+    }
+    
    /// The time contents of file has been created, returns nil if not set
    open internal(set) var creationDate: Date? {
        get {
@@ -92,9 +103,9 @@ open class FileObject: Equatable {
    }
    
    /// return resource type of file, usually directory, regular or symLink
-    open internal(set) var type: URLFileResourceType? {
+    open internal(set) var type: URLFileResourceType {
        get {
-            return allValues[.fileResourceTypeKey] as? URLFileResourceType
+            return allValues[.fileResourceTypeKey] as? URLFileResourceType ?? .unknown
        }
        set {
            allValues[.fileResourceTypeKey] = newValue
@@ -139,21 +150,28 @@ open class FileObject: Equatable {
    
    /// Check `FileObject` equality
    public static func ==(lhs: FileObject, rhs: FileObject) -> Bool {
-        if rhs === lhs {
+        if rhs === lhs  {
            return true
        }
+        #if swift(>=3.1)
+        if Swift.type(of: lhs) != Swift.type(of: rhs) {
+            return false
+        }
+        #else
        if type(of: lhs) != type(of: rhs) {
            return false
        }
-        if let rurl = rhs.url, let lurl = lhs.url {
+        #endif
+        
+        if let rurl = rhs.allValues[.fileURLKey] as? URL, let lurl = lhs.allValues[.fileURLKey] as? URL {
            return rurl == lurl
        }
        return rhs.path == lhs.path && rhs.size == lhs.size && rhs.modifiedDate == lhs.modifiedDate
    }
    
    internal func mapPredicate() -> [String: Any] {
-        let mapDict: [URLResourceKey: String] = [.fileURL: "url", .nameKey: "name", .pathKey: "path", .fileSizeKey: "filesize", .creationDateKey: "creationDate",
-                                                 .contentModificationDateKey: "modifiedDate", .isHiddenKey: "isHidden", .isWritableKey: "isWritable", .serverDate: "serverDate", .entryTag: "entryTag", .mimeType: "mimeType"]
+        let mapDict: [URLResourceKey: String] = [.fileURLKey: "url", .nameKey: "name", .pathKey: "path", .fileSizeKey: "filesize", .creationDateKey: "creationDate",
+                                                 .contentModificationDateKey: "modifiedDate", .isHiddenKey: "isHidden", .isWritableKey: "isWritable", .serverDateKey: "serverDate", .entryTagKey: "entryTag", .mimeTypeKey: "mimeType"]
        let typeDict: [URLFileResourceType: String] = [.directory: "directory", .regular: "regular", .symbolicLink: "symbolicLink", .unknown: "unknown"]
        var result = [String: Any]()
        for (key, value) in allValues {
@@ -166,14 +184,15 @@ open class FileObject: Equatable {
        result["isDirectory"] = self.isDirectory
        result["isRegularFile"] = self.isRegularFile
        result["isSymLink"] = self.isSymLink
-        result["type"] = typeDict[self.type ?? .unknown] ?? "unknown"
+        result["type"] = typeDict[self.type] ?? "unknown"
        return result
    }
    
+    /// Converts macOS spotlight query for searching files to a query that can be used for `searchFiles()` method
    static public func convertPredicate(fromSpotlight query: NSPredicate) -> NSPredicate {
-        let mapDict: [String: URLResourceKey] = [NSMetadataItemURLKey: .fileURL, NSMetadataItemFSNameKey: .nameKey, NSMetadataItemPathKey: .pathKey,
+        let mapDict: [String: URLResourceKey] = [NSMetadataItemURLKey: .fileURLKey, NSMetadataItemFSNameKey: .nameKey, NSMetadataItemPathKey: .pathKey,
                                                 NSMetadataItemFSSizeKey: .fileSizeKey, NSMetadataItemFSCreationDateKey: .creationDateKey,
-                                                 NSMetadataItemFSContentChangeDateKey: .contentModificationDateKey, "kMDItemFSInvisible": .isHiddenKey, "kMDItemFSIsWriteable": .isWritableKey, "kMDItemKind": .mimeType]
+                                                 NSMetadataItemFSContentChangeDateKey: .contentModificationDateKey, "kMDItemFSInvisible": .isHiddenKey, "kMDItemFSIsWriteable": .isWritableKey, "kMDItemKind": .mimeTypeKey]
        
        if let cQuery = query as? NSCompoundPredicate {
            let newSub = cQuery.subpredicates.map { convertPredicate(fromSpotlight: $0 as! NSPredicate) }
@@ -198,36 +217,96 @@ open class FileObject: Equatable {
    }
 }

-internal func resolve(dateString: String) -> Date? {
-    let dateFor: DateFormatter = DateFormatter()
-    dateFor.locale = Locale(identifier: "en_US")
-    dateFor.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ssZ"
-    if let rfc3339 = dateFor.date(from: dateString) {
-        return rfc3339
-    }
-    dateFor.dateFormat = "EEE',' dd' 'MMM' 'yyyy HH':'mm':'ss z"
-    if let rfc1123 = dateFor.date(from: dateString) {
-        return rfc1123
-    }
-    dateFor.dateFormat = "EEEE',' dd'-'MMM'-'yy HH':'mm':'ss z"
-    if let rfc850 = dateFor.date(from: dateString) {
-        return rfc850
-    }
-    dateFor.dateFormat = "EEE MMM d HH':'mm':'ss yyyy"
-    if let asctime = dateFor.date(from: dateString) {
-        return asctime
+/// Containts attributes of a provider.
+open class VolumeObject {
+    /// A `Dictionary` contains volume information,  using `URLResourceKey` keys.
+    open internal(set) var allValues: [URLResourceKey: Any]
+    
+    public init(allValues: [URLResourceKey: Any]) {
+        self.allValues = allValues
    }
    
-    return nil
+    /// The root directory of the resource’s volume, returned as an `URL` object.
+    open internal(set) var url: URL? {
+        get {
+            return allValues[.volumeURLKey] as? URL
+        }
+        set {
+            allValues[.volumeURLKey] = newValue
+        }
+    }
+    
+    /// The name of the volume.
+    open internal(set) var name: String? {
+        get {
+            return allValues[.volumeNameKey] as? String
+        }
+        set {
+            allValues[.volumeNameKey] = newValue
+        }
+    }
+
+    
+    /// the volume’s capacity in bytes, return -1 if is undetermined.
+    open internal(set) var totalCapacity: Int64 {
+        get {
+            return allValues[.volumeTotalCapacityKey] as? Int64 ?? -1
+        }
+        set {
+            allValues[.volumeTotalCapacityKey] = newValue
+        }
+    }
+    
+    /// The volume’s available capacity in bytes.
+    open internal(set) var availableCapacity: Int64 {
+        get {
+            return allValues[.volumeAvailableCapacityKey] as? Int64 ?? 0
+        }
+        set {
+            allValues[.volumeAvailableCapacityKey] = newValue
+        }
+    }
+    
+    open internal(set) var usage: Int64 {
+        get {
+            return totalCapacity >= 0 ? totalCapacity - availableCapacity : -availableCapacity
+        }
+        set {
+            availableCapacity = totalCapacity >= 0 ? totalCapacity - newValue : -newValue
+        }
+    }
+    
+    ///  the volume’s creation date, returned as an `Date` object, or NULL if it cannot be determined
+    open internal(set) var creationDate: Date? {
+        get {
+            return allValues[.volumeCreationDateKey] as? Date
+        }
+        set {
+            allValues[.volumeCreationDateKey] = newValue
+        }
+    }
+    
+    /// Determining whether the volume is read-only
+    open internal(set) var isReadOnly: Bool {
+        get {
+            return allValues[.volumeIsReadOnlyKey] as? Bool ?? false
+        }
+        set {
+            allValues[.volumeIsReadOnlyKey] = newValue
+        }
+    }
+    
+    @available(iOS 10.0, macOS 10.12, tvOS 10.0, *)
+    open internal(set) var isEncrypted: Bool {
+        get {
+            return allValues[.volumeIsEncryptedKey] as? Bool ?? false
+        }
+        set {
+            allValues[.volumeIsEncryptedKey] = !newValue
+        }
+    }
 }

-internal func rfc3339utc(of date:Date) -> String {
-    let fm = DateFormatter()
-    fm.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"
-    fm.timeZone = TimeZone(identifier:"UTC")
-    fm.locale = Locale(identifier:"en_US_POSIX")
-    return fm.string(from:date)
-}

 /// Sorting FileObject array by given criteria, **not thread-safe**
 public struct FileObjectSorting {
@@ -19,7 +19,7 @@ public typealias ImageClass = NSImage
 public typealias SimpleCompletionHandler = ((_ error: Error?) -> Void)?

 /// This protocol defines FileProvider neccesary functions and properties to connect and get contents list
-public protocol FileProviderBasic: class {
+public protocol FileProviderBasic: class, NSSecureCoding {
    /// An string to identify type of provider.
    static var type: String { get }
    
@@ -29,9 +29,6 @@ public protocol FileProviderBasic: class {
    /// The url of which paths should resolve against.
    var baseURL: URL? { get }
    
-    /// Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
-    var currentPath: String { get set }
-    
    /**
     Dispatch queue usually used in query methods.
     Set it to a new object to switch between cuncurrent and serial queues.
@@ -51,41 +48,44 @@ public protocol FileProviderBasic: class {
     
     **Example initialization:**
     ````
-     let credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
+     provider.credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
     ````
     
     - Note: In OAuth based providers like `DropboxFileProvider` and `OneDriveFileProvider`, password is Token.
     use [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) library to fetch clientId and Token of user.
     */
-    var credential: URLCredential? { get }
+    var credential: URLCredential? { get set }
    
    /**
     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
     
     If the directory contains no entries or an error is occured, this method will return the empty array.
     
-     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
-     - Parameter completionHandler: a closure with result of directory entries or error.
-        `contents`: An array of `FileObject` identifying the the directory entries.
-        `error`: Error returned by system.
+     - Parameters:
+       - path: path to target directory. If empty, root will be iterated.
+       - completionHandler: a closure with result of directory entries or error.
+       - contents: An array of `FileObject` identifying the the directory entries.
+       - error: Error returned by system.
     */
-    func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void))
+    func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void)
    
    /**
     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
     
     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
     
-     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
-     - Parameter completionHandler: a closure with result of directory entries or error.
-        `attributes`: A `FileObject` containing the attributes of the item.
-        `error`: Error returned by system.
+     - Parameters:
+       - path: path to target directory. If empty, attributes of root will be returned.
+       - completionHandler: a closure with result of directory entries or error.
+       - attributes: A `FileObject` containing the attributes of the item.
+       - error: Error returned by system.
     */
-    func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void))
+    func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void)
    
    
-    /// Returns total and used capacity in provider container asynchronously.
-    func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void))
+    /// Returns volume/provider information asynchronously.
+    /// - Parameter volumeInfo: Information of filesystem/Provider returned by system/server.
+    func storageProperties(completionHandler: @escaping (_ volumeInfo: VolumeObject?) -> Void)
    
    /**
     Search files inside directory using query asynchronously.
@@ -98,8 +98,11 @@ public protocol FileProviderBasic: class {
       - query: Simple string that file name begins with to be search, case-insensitive.
       - foundItemHandler: Closure which is called when a file is found
       - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+       - files: all files meat the `query` criteria.
+       - error: `Error` returned by server if occured.
     */
-    func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void))
+    @discardableResult
+    func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress?
    
    /**
     Search files inside directory using query asynchronously.
@@ -121,8 +124,12 @@ public protocol FileProviderBasic: class {
       - query: An `NSPredicate` object with keys like `FileObject` members, except `size` which becomes `filesize`.
       - foundItemHandler: Closure which is called when a file is found
       - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+       - files: all files meat the `query` criteria.
+       - error: `Error` returned by server if occured.
+     - Returns: An `Progress` to get progress or cancel progress. Use `completedUnitCount` to iterate count of found items.
     */
-    func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void))
+    @discardableResult
+    func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress?
    
    /**
     Returns an independent url to access the file. Some providers like `Dropbox` due to their nature.
@@ -130,22 +137,29 @@ public protocol FileProviderBasic: class {
     - Parameter path: Relative path of file or directory.
     - Returns: An url, can be used to access to file directly.
    */
-    func url(of path: String?) -> URL
+    func url(of path: String) -> URL
+    
+    
+    /// Returns the relative path of url, wothout percent encoding. Even if url is absolute or
+    /// retrieved from another provider, it will try to resolve the url against `baseURL` of
+    /// current provider. It's highly recomended to use this method for displaying purposes.
+    ///
+    /// - Parameter url: Absolute url to file or directory.
+    /// - Returns: A `String` contains relative path of url against base url.
+    func relativePathOf(url: URL) -> String
    
    /// Checks the connection to server or permission on local
+    ///
+    /// - Note: To prevent race condition, use this method wisely and avoid it as far possible.
+    ///
+    /// - Parameter success: indicated server is reachable or not.
    func isReachable(completionHandler: @escaping(_ success: Bool) -> Void)
 }

 extension FileProviderBasic {
-    public func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
+    public func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
        let predicate = NSPredicate(format: "name BEGINSWITH[c] %@", query)
-        self.searchFiles(path: path, recursive: recursive, query: predicate, foundItemHandler: foundItemHandler, completionHandler: completionHandler)
-    }
-    
-    /// Converts Spotlight search predicate to `FileProvider.searchFiles()` method usable predicate.
-    @available(*, obsoleted: 1.0, renamed: "FileObject.convertProdicate(fromSpotlight:)", message: "Use FileObject.convertProdicate(fromSpotlight:) instead.")
-    public func convertSpotlightPredicateTo(_ query: NSPredicate) -> NSPredicate {
-        return FileObject.convertPredicate(fromSpotlight: query)
+        return self.searchFiles(path: path, recursive: recursive, query: predicate, foundItemHandler: foundItemHandler, completionHandler: completionHandler)
    }
    
    /// The maximum number of queued operations that can execute at the same time.
@@ -159,6 +173,14 @@ extension FileProviderBasic {
            operation_queue.maxConcurrentOperationCount = newValue
        }
    }
+    
+    /// Returns total and used capacity in provider container asynchronously.
+    @available(*, deprecated, message: "Use storageProperties which returns VolumeObject")
+    func storageProperties(completionHandler: @escaping (_ total: Int64, _ used: Int64) -> Void) {
+        self.storageProperties { (info) in
+            completionHandler(info?.totalCapacity ?? -1, info?.usage ?? 0)
+        }
+    }
 }

 /// Checking equality of two file provider, regardless of current path queues and delegates.
@@ -199,7 +221,13 @@ public protocol FileProviderBasicRemote: FileProviderBasic {
    var validatingCache: Bool { get set }
 }

-internal extension FileProviderBasicRemote {
+internal protocol FileProviderBasicRemoteInternal: FileProviderBasic {
+    var completionHandlersForTasks: [Int: SimpleCompletionHandler] { get set }
+    var downloadCompletionHandlersForTasks: [Int: (URL) -> Void] { get set }
+    var dataCompletionHandlersForTasks: [Int: (Data) -> Void] { get set }
+}
+
+internal extension FileProviderBasicRemote {    
    func returnCachedDate(with request: URLRequest, validatingCache: Bool, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> Bool {
        guard let cache = self.cache else { return false }
        if let response = cache.cachedResponse(for: request) {
@@ -230,7 +258,7 @@ internal extension FileProviderBasicRemote {
        return false
    }
    
-    func runDataTask(with request: URLRequest, operationHandle: RemoteOperationHandle? = nil, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) {
+    func runDataTask(with request: URLRequest, operation: FileOperationType? = nil, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) {
        let useCache = self.useCache
        let validatingCache = self.validatingCache
        dispatch_queue.async {
@@ -240,8 +268,7 @@ internal extension FileProviderBasicRemote {
                }
            }
            let task = self.session.dataTask(with: request, completionHandler: completionHandler)
-            task.taskDescription = operationHandle?.operationType.json
-            operationHandle?.add(task: task)
+            task.taskDescription = operation?.json
            task.resume()
        }
    }
@@ -260,24 +287,10 @@ public protocol FileProviderOperations: FileProviderBasic {
       - folder: Directory name.
       - at: Parent path of new directory.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func create(folder: String, at: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
-    
-    /**
-     Creates an new file with data passed to method asynchronously. 
-     Returns error via completionHandler if file is already exists.
-     
-     - Parameters:
-       - file: New file name with extension separated by period.
-       - at: Parent path of new file.
-       - data: Data of new files. Pass nil or `Data()` to create empty file.
-       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
-     */
-    @discardableResult
-    func create(file: String, at: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func create(folder: String, at: String, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Moves a file or directory from `path` to designated path asynchronously.
@@ -288,10 +301,10 @@ public protocol FileProviderOperations: FileProviderBasic {
       - path: original file or directory path.
       - to: destination path of file or directory, including file/directory name.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func moveItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func moveItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Moves a file or directory from `path` to designated path asynchronously.
@@ -303,10 +316,10 @@ public protocol FileProviderOperations: FileProviderBasic {
       - to: destination path of file or directory, including file/directory name.
       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func moveItem(path: String, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func moveItem(path: String, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Copies a file or directory from `path` to designated path asynchronously.
@@ -317,10 +330,10 @@ public protocol FileProviderOperations: FileProviderBasic {
       - path: original file or directory path.
       - to: destination path of file or directory, including file/directory name.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func copyItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func copyItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Copies a file or directory from `path` to designated path asynchronously.
@@ -332,10 +345,10 @@ public protocol FileProviderOperations: FileProviderBasic {
       - to: destination path of file or directory, including file/directory name.
       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func copyItem(path: String, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func copyItem(path: String, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Removes the file or directory at the specified path.
@@ -343,70 +356,102 @@ public protocol FileProviderOperations: FileProviderBasic {
     - Parameters:
       - path: file or directory path.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     
     */
    @discardableResult
-    func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Uploads a file from local file url to designated path asynchronously.
     Method will fail if source is not a local url with `file://` scheme.
     
+     - Note: It's safe to assume that this method only works on individual files and **won't** copy folders recursively.
+     
     - Parameters:
       - localFile: a file url to file.
       - to: destination path of file, including file/directory name.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress.
+     - Returns: An `Progress` to get progress or cancel progress.
     */
    @discardableResult
-    func copyItem(localFile: URL, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func copyItem(localFile: URL, to: String, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Uploads a file from local file url to designated path asynchronously.
     Method will fail if source is not a local url with `file://` scheme.
     
+     - Note: It's safe to assume that this method only works on individual files and **won't** copy folders recursively.
+     
     - Parameters:
       - localFile: a file url to file.
       - to: destination path of file, including file/directory name.
       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress.
+     - Returns: An `Progress` to get progress or cancel progress.
     */
    @discardableResult
-    func copyItem(localFile: URL, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func copyItem(localFile: URL, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Download a file from `path` to designated local file url asynchronously.
     Method will fail if destination is not a local url with `file://` scheme.
     
+     - Note: It's safe to assume that this method only works on individual files and **won't** copy folders recursively.
+     
     - Parameters:
       - path: original file or directory path.
       - toLocalURL: destination local url of file, including file/directory name.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress?
 }

-extension FileProviderOperations {
+public extension FileProviderOperations {
+    /// *DEPRECATED:* Use Use FileProviderReadWrite.writeContents(path:, data:, completionHandler:) method instead.
+    @available(*, deprecated, message: "Use FileProviderReadWrite.writeContents(path:, data:, completionHandler:) method instead.")
    @discardableResult
-    public func moveItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func create(file: String, at: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let path = (at as NSString).appendingPathComponent(file)
+        return (self as? FileProviderReadWrite)?.writeContents(path: path, contents: data, completionHandler: completionHandler)
+    }
+    
+    @discardableResult
+    public func moveItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        return self.moveItem(path: path, to: to, overwrite: false, completionHandler: completionHandler)
    }
    
    @discardableResult
-    public func copyItem(localFile: URL, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func copyItem(localFile: URL, to: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        return self.copyItem(localFile: localFile, to: to, overwrite: false, completionHandler: completionHandler)
    }
    
    @discardableResult
-    public func copyItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func copyItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        return self.copyItem(path: path, to: to, overwrite: false, completionHandler: completionHandler)
    }
 }

+internal extension FileProviderOperations {
+    internal func delegateNotify(_ operation: FileOperationType, error: Error? = nil) {
+        DispatchQueue.main.async(execute: {
+            if let error = error {
+                self.delegate?.fileproviderFailed(self, operation: operation, error: error)
+            } else {
+                self.delegate?.fileproviderSucceed(self, operation: operation)
+            }
+        })
+    }
+    
+    internal func delegateNotify(_ operation: FileOperationType, progress: Double) {
+        DispatchQueue.main.async(execute: {
+            self.delegate?.fileproviderProgress(self, operation: operation, progress: Float(progress))
+        })
+    }
+}
+
 /// Defines method for fetching and modifying file contents
 public protocol FileProviderReadWrite: FileProviderBasic {
    /**
@@ -416,12 +461,12 @@ public protocol FileProviderReadWrite: FileProviderBasic {
     - Parameters:
       - path: Path of file.
       - completionHandler: a closure with result of file contents or error.
-         `contents`: contents of file in a `Data` object.
-         `error`: Error returned by system.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+       - contents: contents of file in a `Data` object.
+       - error: `Error` returned by system if occured.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
    */
    @discardableResult
-    func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle?
+    func contents(path: String, completionHandler: @escaping (_ contents: Data?, _ error: Error?) -> Void) -> Progress?
    
    /**
     Retreives a `Data` object with a portion contents of the file asynchronously vis contents argument of completion handler.
@@ -432,12 +477,12 @@ public protocol FileProviderReadWrite: FileProviderBasic {
       - offset: First byte index which should be read. **Starts from 0.**
       - length: Bytes count of data. Pass `-1` to read until the end of file.
       - completionHandler: a closure with result of file contents or error.
-         `contents`: contents of file in a `Data` object.
-         `error`: Error returned by system.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+       - contents: contents of file in a `Data` object.
+       - error: Error returned by system if occured.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle?
+    func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping (_ contents: Data?, _ error: Error?) -> Void) -> Progress?
    
    /**
     Write the contents of the `Data` to a location asynchronously.
@@ -446,12 +491,12 @@ public protocol FileProviderReadWrite: FileProviderBasic {
     
     - Parameters:
       - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func writeContents(path: String, contents: Data, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Write the contents of the `Data` to a location asynchronously.
@@ -459,13 +504,13 @@ public protocol FileProviderReadWrite: FileProviderBasic {
     
     - Parameters:
       - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
       - atomically: data will be written to a temporary file before writing to final location. Default is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func writeContents(path: String, contents: Data, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, atomically: Bool, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Write the contents of the `Data` to a location asynchronously.
@@ -473,47 +518,47 @@ public protocol FileProviderReadWrite: FileProviderBasic {
     
     - Parameters:
     - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
       - overwrite: Destination file should be overwritten if file is already exists. Default is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func writeContents(path: String, contents: Data, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress?
    
    /**
     Write the contents of the `Data` to a location asynchronously.
     
     - Parameters:
       - path: Path of target file.
-       - contents: Data to be written into file.
+       - contents: Data to be written into file, pass nil to create empty file.
       - overwrite: Destination file should be overwritten if file is already exists. Default is `false`.
       - atomically: data will be written to a temporary file before writing to final location. Default is `false`.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
-     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     - Returns: An `Progress` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
     */
    @discardableResult
-    func writeContents(path: String, contents: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    func writeContents(path: String, contents: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress?
 }

 extension FileProviderReadWrite {
    @discardableResult
-    public func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle?{
+    public func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
        return self.contents(path: path, offset: 0, length: -1, completionHandler: completionHandler)
    }
    
    @discardableResult
-    public func writeContents(path: String, contents: Data, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents: Data?, completionHandler: SimpleCompletionHandler) -> Progress? {
        return self.writeContents(path: path, contents: contents, atomically: false, overwrite: false, completionHandler: completionHandler)
    }
    
    @discardableResult
-    public func writeContents(path: String, contents: Data, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents: Data?, atomically: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        return self.writeContents(path: path, contents: contents, atomically: atomically, overwrite: false, completionHandler: completionHandler)
    }
    
    @discardableResult
-    public func writeContents(path: String, contents: Data, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    public func writeContents(path: String, contents: Data?, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        return self.writeContents(path: path, contents: contents, atomically: false, overwrite: overwrite, completionHandler: completionHandler)
    }
 }
@@ -536,7 +581,7 @@ public protocol FileProviderMonitor: FileProviderBasic {
       - path: path of directory.
       - eventHandler: Closure executed after change, on a secondary thread.
     */
-    func registerNotifcation(path: String, eventHandler: @escaping (() -> Void))
+    func registerNotifcation(path: String, eventHandler: @escaping () -> Void)
    
    /// Stops monitoring the path.
    ///
@@ -559,8 +604,10 @@ public protocol FileProvideUndoable: FileProviderOperations {
    var undoManager: UndoManager? { get set }
    
    /// UndoManager supports undoing this file operation
-    func canUndo(handle: OperationHandle) -> Bool
+    /// - Parameter handle: determines wheither this progress can be rolled back or not.
+    func canUndo(handle: Progress) -> Bool
    /// UndoManager supports undoing this operation
+    /// - Parameter operation: determines wheither this operation can be rolled back or not.
    func canUndo(operation: FileOperationType) -> Bool
 }

@@ -569,10 +616,14 @@ public extension FileProvideUndoable {
        return undoOperation(for: operation) != nil
    }
    
-    public func canUndo(handle: OperationHandle) -> Bool {
-        return canUndo(operation: handle.operationType)
+    public func canUndo(handle: Progress) -> Bool {
+        if let operationType = handle.userInfo[.fileProvderOperationTypeKey] as? FileOperationType {
+            return canUndo(operation: operationType)
+        }
+        return false
    }
    
+    /// Reuturns roll back operation for provided `operation`.
    internal func undoOperation(for operation: FileOperationType) -> FileOperationType? {
        switch operation {
        case .create(path: let path):
@@ -600,68 +651,82 @@ public extension FileProvideUndoable {
    }
 }

+/// This protocol defines method to share a public link with other users
+public protocol FileProviderSharing {
+    /**
+     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
+     
+     - Important: In some providers url will be available for a limitied time, determined in `expiration` argument.
+         e.g. Dropbox links will be expired after 4 hours.
+     
+     - Parameters:
+         - to: path of file, including file/directory name.
+         - completionHandler: a closure with result of directory entries or error.
+         - link: a url returned by Dropbox to share.
+         - attribute: a `FileObject` containing the attributes of the item.
+         - expiration: a `Date` object, determines when the public url will expires.
+         - error: Error returned by server.
+     */
+    func publicLink(to path: String, completionHandler: @escaping (_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)
+}
+
 /// Defines protocol for provider allows all common operations.
-public protocol FileProvider: FileProviderBasic, FileProviderOperations, FileProviderReadWrite, NSCopying {
+public protocol FileProvider: FileProviderOperations, FileProviderReadWrite, NSCopying {
 }

 internal let pathTrimSet = CharacterSet(charactersIn: " /")
 extension FileProviderBasic {
    public var type: String {
+        #if swift(>=3.1)
+        return Swift.type(of: self).type
+        #else
        return type(of: self).type
+        #endif
    }
    
-    /// **DEPRECATED** This property never worked as expected and is redundant as only supported by `LocalFileProvider`.
-    /// To simulate `false` value, assign `URL(fileURLWithPath: "/")` to `baseURL`.
-    @available(*, deprecated, message: "Redundant property, now is always true.")
-    var isPathRelative: Bool { return true }
-    
-    public func url(of path: String? = nil) -> URL {
-        var rpath: String = path ?? self.currentPath
-        rpath = rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath
+    public func url(of path: String) -> URL {
+        var rpath: String = path
+        rpath = rpath.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? rpath
        if let baseURL = baseURL {
            if rpath.hasPrefix("/") {
                rpath.remove(at: rpath.startIndex)
            }
            return URL(string: rpath, relativeTo: baseURL) ?? baseURL
        } else {
-            return URL(string: rpath)!
+            return URL(string: rpath) ?? URL(string: "/")!
        }
    }
    
-    
-    /// Returns the relative path of url, wothout percent encoding. Even if url is absolute or
-    /// retrieved from another provider, it will try to resolve the url against `baseURL` of
-    /// current provider. It's highly recomended to use this method for displaying purposes.
-    ///
-    /// - Parameter url: Absolute url to file or directory.
-    /// - Returns: A `String` contains relative path of url against base url.
    public func relativePathOf(url: URL) -> String {
        // check if url derieved from current base url
        let relativePath = url.relativePath
        if !relativePath.isEmpty, url.baseURL == self.baseURL {
-            return relativePath.removingPercentEncoding ?? relativePath
+            return (relativePath.removingPercentEncoding ?? relativePath).replacingOccurrences(of: "/", with: "", options: .anchored)
        }
        
        // resolve url string against baseurl
-        guard let baseURL = self.baseURL?.standardizedFileURL else { return url.absoluteString }
-        let standardPath = url.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
-        let standardBase = baseURL.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
-        let standardRelativePath = standardPath.replacingOccurrences(of: standardBase, with: "/")
-        return standardRelativePath.removingPercentEncoding ?? standardRelativePath
-    }
-    
-    internal func correctPath(_ path: String?) -> String? {
-        guard let path = path else { return nil }
-        var p = path.hasPrefix("/") ? path : "/" + path
-        if p.hasSuffix("/") {
-            p.remove(at: p.index(before:p.endIndex))
+        if baseURL?.isFileURL ?? false {
+            guard let baseURL = self.baseURL?.standardizedFileURL else { return url.absoluteString }
+            let standardPath = url.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
+            let standardBase = baseURL.absoluteString.replacingOccurrences(of: "file:///private/var/", with: "file:///var/", options: .anchored)
+            let standardRelativePath = standardPath.replacingOccurrences(of: standardBase, with: "/").replacingOccurrences(of: "/", with: "", options: .anchored)
+            return standardRelativePath.removingPercentEncoding ?? standardRelativePath
+        } else {
+            guard let baseURL = self.baseURL else { return url.absoluteString }
+            let standardRelativePath = url.absoluteString.replacingOccurrences(of: baseURL.absoluteString, with: "/").replacingOccurrences(of: "/", with: "", options: .anchored)
+            if URLComponents(string: standardRelativePath)?.host?.isEmpty ?? true {
+                return standardRelativePath.removingPercentEncoding ?? standardRelativePath
+            } else {
+                return relativePath.replacingOccurrences(of: "/", with: "", options: .anchored)
+            }
        }
-        return p
    }
    
    /// Returns a file name supposed to be unique with adding numbers to end of file.
-    /// - Important: It's a synchronous method. Don't use it on matin thread.
+    /// - Important: It's a synchronous method. Don't use it on main thread.
+    /// - Parameter filePath: supposed path of file which should be examined.
    public func fileByUniqueName(_ filePath: String) -> String {
+        //assert(!Thread.isMainThread, "\(#function) is not recommended to be executed on Main Thread.")
        let fileUrl = URL(fileURLWithPath: filePath)
        let dirPath = fileUrl.deletingLastPathComponent().path 
        let fileName = fileUrl.deletingPathExtension().lastPathComponent
@@ -682,7 +747,7 @@ extension FileProviderBasic {
            }
            var i = number ?? 2
            let similiar = contents.map {
-                $0.url?.lastPathComponent ?? $0.name
+                $0.url.lastPathComponent.isEmpty ? $0.name : $0.url.lastPathComponent
            }.filter {
                $0.hasPrefix(result)
            }
@@ -697,16 +762,14 @@ extension FileProviderBasic {
        return (dirPath as NSString).appendingPathComponent(finalFile)
    }
    
-    internal func throwError(_ path: String, code: FoundationErrorEnum) -> NSError {
+    internal func urlError(_ path: String, code: URLError.Code) -> Error {
        let fileURL = self.url(of: path)
-        let domain: String
-        switch code {
-        case is URLError:
-            domain = NSURLErrorDomain
-        default:
-            domain = NSCocoaErrorDomain
-        }
-        return NSError(domain: domain, code: code.rawValue, userInfo: [NSURLErrorFailingURLErrorKey: fileURL, NSURLErrorFailingURLStringErrorKey: fileURL.absoluteString])
+        return URLError(code, userInfo: [NSURLErrorKey: fileURL, NSURLErrorFailingURLErrorKey: fileURL, NSURLErrorFailingURLStringErrorKey: fileURL.absoluteString])
+    }
+    
+    internal func cocoaError(_ path: String, code: CocoaError.Code) -> Error {
+        let fileURL = self.url(of: path)
+        return CocoaError(code, userInfo: [NSFilePathErrorKey: path, NSURLErrorKey: fileURL])
    }
    
    internal func NotImplemented(_ fn: String = #function, file: StaticString = #file) {
@@ -730,19 +793,19 @@ public protocol ExtendedFileProvider: FileProviderBasic {
    func propertiesOfFileSupported(path: String) -> Bool
    
    /**
-     Generates ans returns a thumbnail preview of document asynchronously. The defualt dimension of returned image is different
+     Generates and returns a thumbnail preview of document asynchronously. The defualt dimension of returned image is different
     regarding provider type, usually 64x64 pixels.
     
     - Parameters:
       - path: path of file.
       - completionHandler: a closure with result of preview image or error.
-         `image`: `NSImage`/`UIImage` object contains preview.
-         `error`: Error returned by system.
+       - image: `NSImage`/`UIImage` object contains preview.
+       - error: `Error` returned by system.
    */
-    func thumbnailOfFile(path: String, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void))
+    func thumbnailOfFile(path: String, completionHandler: @escaping (_ image: ImageClass?, _ error: Error?) -> Void)
    
    /**
-     Generates ans returns a thumbnail preview of document asynchronously. The defualt dimension of returned image is different
+     Generates and returns a thumbnail preview of document asynchronously. The defualt dimension of returned image is different
     regarding provider type, usually 64x64 pixels. Default value used when `dimenstion` is `nil`.
     
     - Note: `LocalFileInformationGenerator` variables can be set to change default behavior of
@@ -752,10 +815,10 @@ public protocol ExtendedFileProvider: FileProviderBasic {
       - path: path of file.
       - dimension: width and height of result preview image.
       - completionHandler: a closure with result of preview image or error.
-         `image`: `NSImage`/`UIImage` object contains preview.
-     `error`: Error returned by system.
+       - image: `NSImage`/`UIImage` object contains preview.
+       - error: `Error` returned by system.
     */
-    func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void))
+    func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping (_ image: ImageClass?, _ error: Error?) -> Void)
    
    /**
     Fetching properties of file like dimensions, duration, etc. It's variant depending on file type.
@@ -767,11 +830,11 @@ public protocol ExtendedFileProvider: FileProviderBasic {
     - Parameters:
       - path: path of file.
       - completionHandler: a closure with result of preview image or error.
-         `propertiesDictionary`: A `Dictionary` of proprty keys and values.
-         `keys`: An `Array` contains ordering of keys.
-         `error`: Error returned by system.
+       - propertiesDictionary: A `Dictionary` of proprty keys and values.
+       - keys: An `Array` contains ordering of keys.
+       - error: Error returned by system.
     */
-    func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void))
+    func propertiesOfFile(path: String, completionHandler: @escaping (_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void)
 }

 extension ExtendedFileProvider {
@@ -833,19 +896,20 @@ extension ExtendedFileProvider {
            return resultingImage
        #else
            let ppp = Int(UIScreen.main.scale) // fetch device is retina or not
-            guard let context = UIGraphicsGetCurrentContext() else {
-                return nil
-            }
            size.width  *= CGFloat(ppp)
            size.height *= CGFloat(ppp)
            UIGraphicsBeginImageContext(size)
-            
+            guard let context = UIGraphicsGetCurrentContext() else {
+                return nil
+            }
            context.saveGState()
            let transform = pdfPage.getDrawingTransform(CGPDFBox.mediaBox, rect: rect, rotate: 0, preserveAspectRatio: true)
            context.concatenate(transform)
            
            context.translateBy(x: 0, y: size.height)
            context.scaleBy(x: CGFloat(ppp), y: CGFloat(-ppp))
+            context.setFillColor(UIColor.white.cgColor)
+            context.fill(rect)
            context.drawPDFPage(pdfPage)
            
            context.restoreGState()
@@ -918,10 +982,10 @@ public enum FileOperationType: CustomStringConvertible {
    }
    
    /// Path of subjecting file.
-    public var source: String? {
-        guard let reflect = Mirror(reflecting: self).children.first?.value else { return nil }
+    public var source: String {
+        let reflect = Mirror(reflecting: self).children.first!.value
        let mirror = Mirror(reflecting: reflect)
-        return reflect as? String ?? mirror.children.first?.value as? String
+        return reflect as? String ?? mirror.children.first?.value as! String
    }
    
    /// Path of subjecting file.
@@ -942,6 +1006,8 @@ public enum FileOperationType: CustomStringConvertible {
        }
        let dest = json["dest"] as? String
        switch type {
+        case "Fetch":
+            self = .fetch(path: source)
        case "Create":
            self = .create(path: source)
        case "Modify":
@@ -971,33 +1037,8 @@ public enum FileOperationType: CustomStringConvertible {
 }

 /// Allows to get progress or cancel an in-progress operation, useful for remote providers
-public protocol OperationHandle {
-    /// Operation supposed to be done on files. Contains file paths as associated value.
-    var operationType: FileOperationType { get }
-    
-    /// Bytes written/read by operation so far.
-    var bytesSoFar: Int64 { get }
-    
-    /// Total bytes of operation.
-    var totalBytes: Int64 { get }
-    
-    /// Operation is progress or not, Returns false if operation is done or not initiated yet.
-    var inProgress: Bool { get }
-    
-    /// Progress of operation, usually equals with `bytesSoFar/totalBytes`. or NaN if not available.
-    var progress: Float { get }
-    
-    /// Cancels operation while in progress, or cancels data/download/upload url session task.
-    func cancel() -> Bool
-}
-
-public extension OperationHandle {
-    public var progress: Float {
-        let bytesSoFar = self.bytesSoFar
-        let totalBytes = self.totalBytes
-        return totalBytes > 0 ? Float(Double(bytesSoFar) / Double(totalBytes)) : Float.nan
-    }
-}
+@available(*, obsoleted: 1.0, message: "Use Foudation.Progress class instead.")
+public protocol OperationHandle {}

 /// Delegate methods for reporting provider's operation result and progress, when it's ready to update
 /// user interface.
@@ -1008,7 +1049,7 @@ public protocol FileProviderDelegate: class {
    func fileproviderSucceed(_ fileProvider: FileProviderOperations, operation: FileOperationType)
    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation finished with failure.
    /// This method is called in main thread to avoids UI bugs.
-    func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperationType)
+    func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperationType, error: Error)
    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation progess.
    /// Supported by some providers, especially remote ones.
    /// This method is called in main thread to avoids UI bugs.
@@ -1024,17 +1065,3 @@ public protocol FileOperationDelegate: class {
    /// fileProvider(_:shouldProceedAfterError:copyingItemAtPath:toPath:) gives the delegate an opportunity to recover from or continue copying after an error. If an error occurs, the error object will contain an ErrorType indicating the problem. The source path and destination paths are also provided. If this method returns true, the FileProvider instance will continue as if the error had not occurred. If this method returns false, the NSFileManager instance will stop copying, return false from copyItemAtPath:toPath:error: and the error will be provied there.
    func fileProvider(_ fileProvider: FileProviderOperations, shouldProceedAfterError error: Error, operation: FileOperationType) -> Bool
 }
-
-internal class Weak<T: AnyObject> {
-    weak var value : T?
-    init (_ value: T) {
-        self.value = value
-    }
-}
-
-/// For internal use in `FileProvider` framework
-public protocol FoundationErrorEnum {
-    init? (rawValue: Int)
-    var rawValue: Int { get }
-}
-
@@ -1,182 +0,0 @@
-//
-//  FileProviderExtensions.swift
-//  FileProvider
-//
-//  Created by Amir Abbas on 12/27/1395 AP.
-//
-//
-
-import Foundation
-
-extension Array where Element: FileObject {
-    /// Returns a sorted array of `FileObject`s by criterias set in attributes.
-    public func sort(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) -> [Element] {
-        let sorting = FileObjectSorting(type: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
-        return sorting.sort(self) as! [Element]
-    }
-    
-    /// Sorts array of `FileObject`s by criterias set in attributes.
-    public mutating func sorted(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) {
-        self = self.sort(by: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
-    }
-}
-
-extension URLFileResourceType {
-    /// Returns corresponding `URLFileResourceType` of a `FileAttributeType` value
-    public init(fileTypeValue: FileAttributeType) {
-        switch fileTypeValue {
-        case FileAttributeType.typeCharacterSpecial: self = .characterSpecial
-        case FileAttributeType.typeDirectory: self = .directory
-        case FileAttributeType.typeBlockSpecial: self = .blockSpecial
-        case FileAttributeType.typeRegular: self = .regular
-        case FileAttributeType.typeSymbolicLink: self = .symbolicLink
-        case FileAttributeType.typeSocket: self = .socket
-        case FileAttributeType.typeUnknown: self = .unknown
-        default: self = .unknown
-        }
-    }
-}
-
-internal extension URLResourceKey {
-    static let fileURL = URLResourceKey(rawValue: "NSURLFileURLKey")
-    static let serverDate = URLResourceKey(rawValue: "NSURLServerDateKey")
-    static let entryTag = URLResourceKey(rawValue: "NSURLEntryTagKey")
-    static let mimeType = URLResourceKey(rawValue: "NSURLMIMETypeIdentifierKey")
-}
-
-internal extension URL {
-    var uw_scheme: String {
-        return self.scheme ?? ""
-    }
-    
-    var fileIsDirectory: Bool {
-        return (try? self.resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory ?? false
-    }
-    
-    var fileSize: Int64 {
-        return Int64((try? self.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1)
-    }
-    
-    var fileExists: Bool {
-        return self.isFileURL && FileManager.default.fileExists(atPath: self.path)
-    }
-}
-
-internal extension Data {
-    internal var isPDF: Bool {
-        return self.count > 4 && self.scanString(length: 4, using: .ascii) == "%PDF"
-    }
-    
-    init? (jsonDictionary dictionary: [String: AnyObject]) {
-        guard let data = try? JSONSerialization.data(withJSONObject: dictionary, options: []) else {
-            return nil
-        }
-        self = data
-    }
-    
-    func deserializeJSON() -> [String: AnyObject]? {
-        if let dic = try? JSONSerialization.jsonObject(with: self, options: []) as? [String: AnyObject] {
-            return dic
-        }
-        return nil
-    }
-    
-    init<T>(value: T) {
-        var value = value
-        self = Data(buffer: UnsafeBufferPointer(start: &value, count: 1))
-    }
-    
-    func scanValue<T>() -> T? {
-        guard MemoryLayout<T>.size <= self.count else { return nil }
-        return self.withUnsafeBytes { $0.pointee }
-    }
-    
-    func scanValue<T>(start: Int) -> T? {
-        let length = MemoryLayout<T>.size
-        guard self.count >= start + length else { return nil }
-        return self.subdata(in: start..<start+length).withUnsafeBytes { $0.pointee }
-    }
-    
-    func scanString(start: Int = 0, length: Int, using encoding: String.Encoding = .utf8) -> String? {
-        guard self.count >= start + length else { return nil }
-        return String(data: self.subdata(in: start..<start+length), encoding: encoding)
-    }
-    
-    static func mapMemory<T, U>(from: T) -> U? {
-        guard MemoryLayout<T>.size >= MemoryLayout<U>.size else { return nil }
-        let data = Data(value: from)
-        return data.scanValue()
-    }
-}
-
-internal extension String {
-    init? (jsonDictionary: [String: AnyObject]) {
-        guard let data = Data(jsonDictionary: jsonDictionary) else {
-            return nil
-        }
-        self.init(data: data, encoding: .utf8)
-    }
-    
-    func deserializeJSON(using encoding: String.Encoding = .utf8) -> [String: AnyObject]? {
-        guard let data = self.data(using: encoding) else {
-            return nil
-        }
-        return data.deserializeJSON()
-    }
-}
-
-internal extension TimeInterval {
-    internal var formatshort: String {
-        var result = "0:00"
-        if self < TimeInterval(Int32.max) {
-            result = ""
-            var time = DateComponents()
-            time.hour   = Int(self / 3600)
-            time.minute = Int((self.truncatingRemainder(dividingBy: 3600)) / 60)
-            time.second = Int(self.truncatingRemainder(dividingBy: 60))
-            let formatter = NumberFormatter()
-            formatter.paddingCharacter = "0"
-            formatter.minimumIntegerDigits = 2
-            formatter.maximumFractionDigits = 0
-            let formatterFirst = NumberFormatter()
-            formatterFirst.maximumFractionDigits = 0
-            if time.hour! > 0 {
-                result = "\(formatterFirst.string(from: NSNumber(value: time.hour!))!):\(formatter.string(from: NSNumber(value: time.minute!))!):\(formatter.string(from: NSNumber(value: time.second!))!)"
-            } else {
-                result = "\(formatterFirst.string(from: NSNumber(value: time.minute!))!):\(formatter.string(from: NSNumber(value: time.second!))!)"
-            }
-        }
-        result = result.trimmingCharacters(in: CharacterSet(charactersIn: ": "))
-        return result
-    }
-}
-
-extension NSPredicate {
-    func findValue(forKey key: String?, operator op: NSComparisonPredicate.Operator? = nil) -> Any? {
-        let val = findAllValues(forKey: key).lazy.filter { (op == nil || $0.operator == op!) && !$0.not }
-        return val.first?.value
-    }
-    
-    func findAllValues(forKey key: String?) -> [(value: Any, operator: NSComparisonPredicate.Operator, not: Bool)] {
-        if let cQuery = self as? NSCompoundPredicate {
-            let find = cQuery.subpredicates.flatMap { ($0 as! NSPredicate).findAllValues(forKey: key) }
-            if cQuery.compoundPredicateType == .not {
-                return find.map { return ($0.value, $0.operator, !$0.not) }
-            }
-            return find
-        } else if let cQuery = self as? NSComparisonPredicate {
-            if cQuery.leftExpression.expressionType == .keyPath, key == nil || cQuery.leftExpression.keyPath == key!, let const = cQuery.rightExpression.constantValue {
-                return [(value: const, operator: cQuery.predicateOperatorType, false)]
-            }
-            if cQuery.rightExpression.expressionType == .keyPath, key == nil || cQuery.rightExpression.keyPath == key!, let const = cQuery.leftExpression.constantValue {
-                return [(value: const, operator: cQuery.predicateOperatorType, false)]
-            }
-            return []
-        } else {
-            return []
-        }
-    }
-}
-
-extension URLError.Code: FoundationErrorEnum {}
-extension CocoaError.Code: FoundationErrorEnum {}
@@ -0,0 +1,550 @@
+//
+//  HTTPFileProvider.swift
+//  FilesProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+
+/**
+ The abstract base class for all REST/Web based providers such as WebDAV, Dropbox, OneDrive, Google Drive, etc. and encapsulates basic
+ functionalitis such as downloading/uploading.
+ 
+ No instance of this class should (and can) be created. Use derived classes instead. It leads to a crash with `fatalError()`.
+ */
+open class HTTPFileProvider: FileProviderBasicRemote, FileProviderOperations, FileProviderReadWrite {
+    open class var type: String { fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.") }
+    open let baseURL: URL?
+    
+    /// **OBSOLETED** Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
+    @available(*, obsoleted: 0.22, message: "This property is redundant with almost no use internally.")
+    open var currentPath: String = ""
+    
+    open var dispatch_queue: DispatchQueue
+    open var operation_queue: OperationQueue {
+        willSet {
+            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
+        }
+    }
+    
+    open weak var delegate: FileProviderDelegate?
+    open var credential: URLCredential? {
+        didSet {
+            sessionDelegate?.credential = self.credential
+        }
+    }
+    open private(set) var cache: URLCache?
+    public var useCache: Bool
+    public var validatingCache: Bool
+    
+    fileprivate var _session: URLSession!
+    internal fileprivate(set) var sessionDelegate: SessionDelegate?
+    public var session: URLSession {
+        get {
+            if _session == nil {
+                self.sessionDelegate = SessionDelegate(fileProvider: self)
+                let config = URLSessionConfiguration.default
+                config.urlCache = cache
+                config.requestCachePolicy = .returnCacheDataElseLoad
+                _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: self.operation_queue)
+                _session.sessionDescription = UUID().uuidString
+                initEmptySessionHandler(_session.sessionDescription!)
+            }
+            return _session
+        }
+        
+        set {
+            assert(newValue.delegate is SessionDelegate, "session instances should have a SessionDelegate instance as delegate.")
+            _session = newValue
+            if _session.sessionDescription?.isEmpty ?? true {
+                _session.sessionDescription = UUID().uuidString
+            }
+            self.sessionDelegate = newValue.delegate as? SessionDelegate
+            initEmptySessionHandler(_session.sessionDescription!)
+        }
+    }
+    
+    fileprivate var _longpollSession: URLSession?
+    /// This session has extended timeout up to 10 minutes, suitable for monitoring.
+    internal var longpollSession: URLSession {
+        if _longpollSession == nil {
+            let config = URLSessionConfiguration.default
+            config.timeoutIntervalForRequest = 600
+            _longpollSession = URLSession(configuration: config, delegate: nil, delegateQueue: nil)
+        }
+        return _longpollSession!
+    }
+    
+    /**
+     This is parent initializer for subclasses. Using this method on `HTTPFileProvider` will fail as `type` is not implemented.
+     
+     - Parameters:
+     - baseURL: Location of WebDAV server.
+     - credential: An `URLCredential` object with `user` and `password`.
+     - cache: A URLCache to cache downloaded files and contents.
+     */
+    public init(baseURL: URL?, credential: URLCredential?, cache: URLCache?) {
+        // Make base url absolute and path as directory
+        let urlStr = baseURL?.absoluteString
+        self.baseURL = urlStr.flatMap { $0.hasSuffix("/") ? URL(string: $0) : URL(string: $0 + "/") }
+        self.useCache = false
+        self.validatingCache = true
+        self.cache = cache
+        self.credential = credential
+        
+        #if swift(>=3.1)
+            let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+            let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
+        operation_queue = OperationQueue()
+        operation_queue.name = "\(queueLabel).Operation"
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    public func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.useCache, forKey: "useCache")
+        aCoder.encode(self.validatingCache, forKey: "validatingCache")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    open func copy(with zone: NSZone? = nil) -> Any {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    deinit {
+        if let sessionuuid = _session?.sessionDescription {
+            removeSessionHandler(for: sessionuuid)
+        }
+        
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
+    }
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func storageProperties(completionHandler: @escaping (_ volumeInfo: VolumeObject?) -> Void) {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        self.storageProperties { volume in
+            completionHandler(volume != nil)
+        }
+    }
+    
+    open weak var fileOperationDelegate: FileOperationDelegate?
+    
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
+        return doOperation(.create(path: path), completionHandler: completionHandler)
+    }
+    
+    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.move(source: path, destination: toPath), overwrite: overwrite, completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.copy(source: path, destination: toPath), overwrite: overwrite, completionHandler: completionHandler)
+    }
+    
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        return doOperation(.remove(path: path), completionHandler: completionHandler)
+    }
+    
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        // check file is not a folder
+        guard (try? localFile.resourceValues(forKeys: [.fileResourceTypeKey]))?.fileResourceType ?? .unknown == .regular else {
+            dispatch_queue.async {
+                completionHandler?(self.urlError(localFile.path, code: .fileIsDirectory))
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let request = self.request(for: operation, overwrite: overwrite)
+        return upload_simple(toPath, request: request, localFile: localFile, operation: operation, completionHandler: completionHandler)
+    }
+    
+    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: destURL.absoluteString)
+        let request = self.request(for: operation)
+        let cantLoadError = urlError(path, code: .cannotLoadFromNetwork)
+        return self.download_simple(path: path, request: request, operation: operation, completionHandler: { [weak self] (tempURL, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let tempURL = tempURL else {
+                    throw cantLoadError
+                }
+                
+                var coordError: NSError?
+                NSFileCoordinator().coordinate(writingItemAt: tempURL, options: .forMoving, writingItemAt: destURL, options: .forReplacing, error: &coordError, byAccessor: { (tempURL, destURL) in
+                    do {
+                        try FileManager.default.moveItem(at: tempURL, to: destURL)
+                        
+                        completionHandler?(nil)
+                        self?.delegateNotify(operation)
+                    } catch {
+                        completionHandler?(error)
+                        self?.delegateNotify(operation, error: error)
+                    }
+                })
+                
+                if let error = coordError {
+                    throw error
+                }
+            } catch {
+                completionHandler?(error)
+                self?.delegateNotify(operation, error: error)
+            }
+        })
+    }
+    
+    /**
+     Progressively fetch data of file and returns fetched data in `progressHandler`.
+     If path specifies a directory, or if some other error occurs, data will be nil.
+     
+     - Parameters:
+       - path: Path of file.
+       - progressHandler: a closure called every time a new `Data` is available.
+       - position: start position of data fetched.
+       - data: a portion of contents of file in a `Data` object.
+       - completionHandler: a closure with result of file contents or error.
+       - error: `Error` returned by system if occured.
+     - Returns: An `Progress` to get progress or cancel progress.
+     */
+    open func contents(path: String, progressHandler: @escaping (_ position: Int64, _ data: Data) -> Void, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
+        let request = self.request(for: operation)
+        var position: Int64 = 0
+        return download_progressive(path: path, request: request, operation: operation, progressHandler: { data in
+            progressHandler(position, data)
+            position += Int64(data.count)
+        }, completionHandler: (completionHandler ?? { _ in return }))
+    }
+    
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
+            return nil
+        }
+        
+        let operation = FileOperationType.fetch(path: path)
+        var request = self.request(for: operation)
+        let cantLoadError = urlError(path, code: .cannotLoadFromNetwork)
+        request.set(httpRangeWithOffset: offset, length: length)
+        return self.download_simple(path: path, request: request, operation: operation, completionHandler: { (tempURL, error) in
+            do {
+                if let error = error {
+                    throw error
+                }
+                
+                guard let tempURL = tempURL else {
+                    throw cantLoadError
+                }
+                
+                let data = try Data(contentsOf: tempURL)
+                completionHandler(data, nil)
+            } catch {
+                completionHandler(nil, error)
+            }
+        })
+    }
+    
+    public func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.modify(path: path)
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        let request = self.request(for: operation, overwrite: overwrite, attributes: [.contentModificationDateKey: Date()])
+        return upload_simple(path, request: request, data: data ?? Data(), operation: operation, completionHandler: completionHandler)
+    }
+    
+    internal func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey: Any] = [:]) -> URLRequest {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    internal func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        fatalError("HTTPFileProvider is an abstract class. Please implement \(#function) in subclass.")
+    }
+    
+    internal func multiStatusHandler(source: String, data: Data, completionHandler: SimpleCompletionHandler) -> Void {
+        // WebDAV will override this function
+    }
+    
+    fileprivate func doOperation(_ operation: FileOperationType, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
+            return nil
+        }
+        
+        let progress = Progress(totalUnitCount: 1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let request = self.request(for: operation, overwrite: overwrite)
+        
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderHTTPError?
+            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
+                serverError = self.serverError(with: code, path: operation.source, data: data)
+            }
+            
+            if let response = response as? HTTPURLResponse, FileProviderHTTPErrorCode(rawValue: response.statusCode) == .multiStatus, let data = data {
+                self.multiStatusHandler(source: operation.source, data: data, completionHandler: completionHandler)
+            }
+            
+            if serverError == nil && error == nil {
+                progress.completedUnitCount = 1
+            } else {
+                progress.cancel()
+            }
+            completionHandler?(serverError ?? error)
+            self.delegateNotify(operation, error: serverError ?? error)
+        })
+        task.taskDescription = operation.json
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+    
+    /// This method should be used in subclasses to fetch directory content from servers which support paginated results.
+    /// Almost all HTTP based provider, except WebDAV, supports this method.
+    ///
+    /// - Important: Please use `[weak self]` when implementing handlers to prevent retain cycles. In these cases,
+    ///     return `nil` as the result of handler as the operation will be aborted.
+    ///
+    /// - Parameters:
+    ///    - path: path of directory which enqueued for listing, for informational use like errpr reporting.
+    ///    - requestHandler: Get token of next page and returns appropriate `URLRequest` to be sent to server.
+    ///        handler can return `nil` to cancel entire operation.
+    ///    - token: Token of the page which `URLRequest` is needed, token will be `nil` for initial page. .
+    ///    - pageHandler: Handler which is called after fetching results of a page to parse data. will return parse result as
+    ///        array of `FileObject` or error if data is nil or parsing is failed. Method will not continue to next page if
+    ///        `error` is returned, otherwise `nextToken` will be used for next page. `nil` value for `newToken` will indicate
+    ///        last page of directory contents.
+    ///    - data: Raw data returned from server. Handler should parse them and return files.
+    ///    - progress: `Progress` object that `completedUnits` will be increased when a new `FileObject` is parsed in method.
+    ///    - completionHandler: All file objects returned by `pageHandler` will be passed to this handler, or error if occured.
+    ///        This handler will be called when `pageHandler` returns `nil for `newToken`.
+    ///    - contents: all files parsed via `pageHandler` will be return aggregated.
+    ///    - error: `Error` returned by server. `nil` means success. If exists, it means `contents` are incomplete.
+    internal func paginated(_ path: String, requestHandler: @escaping (_ token: String?) -> URLRequest?, pageHandler: @escaping (_ data: Data?, _ progress: Progress) -> (files: [FileObject], error: Error?, newToken: String?), completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) -> Progress {
+        let progress = Progress(totalUnitCount: -1)
+        self.paginated(path, startToken: nil, currentProgress: progress, previousResult: [], requestHandler: requestHandler, pageHandler: pageHandler, completionHandler: completionHandler)
+        return progress
+    }
+    
+    // codebeat:disable[ARITY]
+    private func paginated(_ path: String, startToken: String?, currentProgress progress: Progress, previousResult: [FileObject], requestHandler: @escaping (_ token: String?) -> URLRequest?, pageHandler: @escaping (_ data: Data?, _ progress: Progress) -> (files: [FileObject], error: Error?, newToken: String?), completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
+        guard !progress.isCancelled, let request = requestHandler(startToken) else {
+            return
+        }
+        
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            if let error = error {
+                completionHandler(previousResult, error)
+                return
+            }
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                let responseError = self.serverError(with: rCode, path: path, data: data)
+                completionHandler(previousResult, responseError)
+                return
+            }
+            
+            let (newFiles, err, newToken) = pageHandler(data, progress)
+            if let error = err {
+                completionHandler(previousResult, error)
+                return
+            }
+            let files = previousResult + newFiles
+            if let newToken = newToken, !progress.isCancelled {
+                _ = self.paginated(path, startToken: newToken, currentProgress: progress, previousResult: files, requestHandler: requestHandler, pageHandler: pageHandler, completionHandler: completionHandler)
+            } else {
+                completionHandler(files, nil)
+            }
+            
+        })
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+    }
+    // codebeat:enable[ARITY]
+ 
+    internal var maxUploadSimpleSupported: Int64 { return Int64.max }
+    
+    internal func upload_simple(_ targetPath: String, request: URLRequest, data: Data? = nil, localFile: URL? = nil, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let size: Int64
+        if let data = data {
+            size = Int64(data.count)
+        } else if let localFile = localFile {
+            let fSize = (try? localFile.resourceValues(forKeys: [.fileSizeKey]))?.fileSize
+            size = Int64(fSize ?? -1)
+        } else {
+            return nil
+        }
+        if size > maxUploadSimpleSupported {
+            let error = self.serverError(with: .payloadTooLarge, path: targetPath, data: nil)
+            completionHandler?(error)
+            self.delegateNotify(operation, error: error)
+            return nil
+        }
+        
+        var progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        progress.totalUnitCount = size
+        
+        let taskHandler = { (task: URLSessionTask) -> Void in
+            completionHandlersForTasks[self.session.sessionDescription!]?[task.taskIdentifier] = { [weak self] error in
+                var responseError: FileProviderHTTPError?
+                if let code = (task.response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                    // We can't fetch server result from delegate!
+                    responseError = self?.serverError(with: rCode, path: targetPath, data: nil)
+                }
+                if !(responseError == nil && error == nil) {
+                    progress.cancel()
+                }
+                completionHandler?(responseError ?? error)
+                self?.delegateNotify(operation, error: responseError ?? error)
+            }
+            task.taskDescription = operation.json
+            task.addObserver(self.sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent), options: .new, context: &progress)
+            progress.cancellationHandler = { [weak task] in
+                task?.cancel()
+            }
+            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+            task.resume()
+        }
+        
+        if let data = data {
+            let task = session.uploadTask(with: request, from: data)
+            taskHandler(task)
+        } else if let localFile = localFile {
+            var error: NSError?
+            NSFileCoordinator().coordinate(readingItemAt: localFile, options: .forUploading, error: &error, byAccessor: { (url) in
+                let task = self.session.uploadTask(with: request, fromFile: localFile)
+                taskHandler(task)
+            })
+            if let error = error {
+                completionHandler?(error)
+            }
+        }
+        
+        return progress
+    }
+    
+    internal func download_progressive(path: String, request: URLRequest, operation: FileOperationType, responseHandler: ((_ response: URLResponse) -> Void)? = nil, progressHandler: @escaping (_ data: Data) -> Void, completionHandler: @escaping (_ error: Error?) -> Void) -> Progress? {
+        var progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.dataTask(with: request)
+        responseCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { response in
+            responseHandler?(response)
+        }
+        
+        dataCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { data in
+            progressHandler(data)
+        }
+        
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            if error != nil {
+                progress.cancel()
+            }
+            completionHandler(error)
+            self.delegateNotify(operation, error: error)
+        }
+        
+        task.taskDescription = operation.json
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+    
+    internal func download_simple(path: String, request: URLRequest, operation: FileOperationType, completionHandler: @escaping ((_ tempURL: URL?, _ error: Error?) -> Void)) -> Progress? {
+        var progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.setUserInfoObject(Progress.FileOperationKind.downloading, forKey: .fileOperationKindKey)
+        
+        let task = session.downloadTask(with: request)
+        completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { error in
+            if error != nil {
+                progress.cancel()
+            }
+            completionHandler(nil, error)
+            self.delegateNotify(operation, error: error)
+        }
+        downloadCompletionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] = { tempURL in
+            guard let httpResponse = task.response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
+                let code = FileProviderHTTPErrorCode(rawValue: (task.response as? HTTPURLResponse)?.statusCode ?? -1)
+                let errorData : Data? = try? Data(contentsOf: tempURL)
+                let serverError = code.flatMap { self.serverError(with: $0, path: path, data: errorData) }
+                if serverError != nil {
+                    progress.cancel()
+                }
+                completionHandler(nil, serverError)
+                self.delegateNotify(operation)
+                return
+            }
+            
+            completionHandler(tempURL, nil)
+        }
+        task.taskDescription = operation.json
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived), options: .new, context: &progress)
+        task.addObserver(sessionDelegate!, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive), options: .new, context: &progress)
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
+    }
+}
+
+extension HTTPFileProvider: FileProvider { }
@@ -17,11 +17,13 @@ import Foundation
 open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndoable {
    open class var type: String { return "Local" }
    open fileprivate(set) var baseURL: URL?
-    open var currentPath: String
+    /// **OBSOLETED** Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
+    @available(*, obsoleted: 0.21, message: "This property is redundant with almost no use internally.")
+    open var currentPath: String = ""
    open var dispatch_queue: DispatchQueue
    open var operation_queue: OperationQueue
    open weak var delegate: FileProviderDelegate?
-    open internal(set) var credential: URLCredential?
+    open var credential: URLCredential?
    
    /// Underlying `FileManager` object for listing and metadata fetching.
    open private(set) var fileManager = FileManager()
@@ -42,12 +44,6 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    */
    open var isCoorinating: Bool
    
-    /// **OBSOLETED**: Use FileProvider.init(for:in:) instead.
-    @available(*, obsoleted: 1.0, renamed: "init(for:in:)", message: "Use FileProvider.init(for:in:) instead.")
-    public convenience init (directory: FileManager.SearchPathDirectory = .documentDirectory, domainMask: FileManager.SearchPathDomainMask = .userDomainMask) {
-        self.init(baseURL: FileManager.default.urls(for: directory, in: domainMask).first!)
-    }
-    
    /**
     Initializes provider for the specified common directory in the requested domains.
     default values are `directory: .documentDirectory, domainMask: .userDomainMask`.
@@ -76,7 +72,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            return nil
        }
        
-        var finalBaseURL = baseURL
+        var finalBaseURL = baseURL.absoluteURL
        
        switch directory {
        case .documentDirectory:
@@ -104,27 +100,50 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
        guard baseURL.isFileURL else {
            fatalError("Cannot initialize a Local provider from remote URL.")
        }
-        self.baseURL = baseURL
-        self.currentPath = ""
+        self.baseURL = URL(fileURLWithPath: baseURL.path, isDirectory: true)
        self.credential = nil
        self.isCoorinating = false
        
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        #if swift(>=3.1)
+        let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+        let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
        operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
+        operation_queue.name = "\(queueLabel).Operation"
        
        fileProviderManagerDelegate = LocalFileProviderManagerDelegate(provider: self)
        opFileManager.delegate = fileProviderManagerDelegate
-        
    }
    
-    /// **DEPRECATED:** No longer is in use and overriding this method has no effect anymore.
-    @available(*, deprecated, message: "Overriding this method has no effect anymore.")
-    open class func defaultBaseURL() -> URL {
-        return FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else {
+            return nil
+        }
+        self.init(baseURL: baseURL)
+        self.isCoorinating = aDecoder.decodeBool(forKey: "isCoorinating")
    }
    
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
+    open func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "currentPath")
+        aCoder.encode(self.isCoorinating, forKey: "isCoorinating")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    public func copy(with zone: NSZone? = nil) -> Any {
+        let copy = LocalFileProvider(baseURL: self.baseURL!)
+        copy.undoManager = self.undoManager
+        copy.isCoorinating = self.isCoorinating
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        return copy
+    }
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
        dispatch_queue.async {
            do {
                let contents = try self.fileManager.contentsOfDirectory(at: self.url(of: path), includingPropertiesForKeys: nil, options: .skipsSubdirectoryDescendants)
@@ -133,44 +152,58 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                    return LocalFileObject(fileWithPath: path, relativeTo: self.baseURL)
                })
                completionHandler(filesAttributes, nil)
-            } catch let e {
-                completionHandler([], e)
+            } catch {
+                completionHandler([], error)
            }
        }
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    open func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
        dispatch_queue.async {
            completionHandler(LocalFileObject(fileWithPath: path, relativeTo: self.baseURL), nil)
        }
    }
    
-    open func storageProperties(completionHandler: (@escaping (_ total: Int64, _ used: Int64) -> Void)) {
-        let values = try? baseURL?.resourceValues(forKeys: [.volumeTotalCapacityKey, .volumeAvailableCapacityKey])
-        let totalSize = Int64(values??.volumeTotalCapacity ?? -1)
-        let freeSize = Int64(values??.volumeAvailableCapacity ?? 0)
-        completionHandler(totalSize, totalSize - freeSize)
+    public func storageProperties(completionHandler: @escaping (_ volumeInfo: VolumeObject?) -> Void) {
+        dispatch_queue.async {
+            var keys: Set<URLResourceKey> = [.volumeTotalCapacityKey, .volumeAvailableCapacityKey, .volumeURLKey, .volumeNameKey, .volumeIsReadOnlyKey, .volumeCreationDateKey]
+            if #available(iOS 10.0, macOS 10.12, tvOS 10.0, *) {
+                keys.insert(.isEncryptedKey)
+            }
+            let values: URLResourceValues? = self.baseURL.flatMap { try? $0.resourceValues(forKeys: keys) }
+            completionHandler(values.flatMap({ VolumeObject(allValues: $0.allValues) }))
+        }
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(self.url(of: path), forKey: .fileURLKey)
+        
        dispatch_queue.async {
+            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
            let iterator = self.fileManager.enumerator(at: self.url(of: path), includingPropertiesForKeys: nil, options: recursive ? [] : [.skipsSubdirectoryDescendants, .skipsPackageDescendants]) { (url, e) -> Bool in
                completionHandler([], e)
                return true
            }
            var result = [LocalFileObject]()
            while let fileURL = iterator?.nextObject() as? URL {
+                if progress.isCancelled {
+                    break
+                }
                let path = self.relativePathOf(url: fileURL)
                if let fileObject = LocalFileObject(fileWithPath: path, relativeTo: self.baseURL), query.evaluate(with: fileObject.mapPredicate()) {
                    result.append(fileObject)
+                    progress.completedUnitCount = Int64(result.count)
                    foundItemHandler?(fileObject)
                }
            }
            completionHandler(result, nil)
        }
+        
+        return progress
    }
    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+    open func isReachable(completionHandler: @escaping (_ success: Bool) -> Void) {
        dispatch_queue.async {
            completionHandler(self.fileManager.isReadableFile(atPath: self.baseURL!.path))
        }
@@ -179,71 +212,77 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    open weak var fileOperationDelegate : FileOperationDelegate?
    
    @discardableResult
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
-        return self.doOperation(opType, completionHandler: completionHandler)
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
-    open func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let fileName = fileName.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
-        let path = (atPath as NSString).appendingPathComponent(fileName)
-        let opType = FileOperationType.create(path: path)
+    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.move(source: path, destination: toPath)
        
-        return self.doOperation(opType, data: data, atomically: true, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.move(source: path, destination: toPath)
-
-        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
-            completionHandler?(self.throwError(toPath, code: CocoaError.fileWriteFileExists as FoundationErrorEnum))
-            return nil
-        }
-        
-        return self.doOperation(opType, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: toPath)
-        
-        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
-            self.dispatch_queue.async {
-                completionHandler?(self.throwError(toPath, code: CocoaError.fileWriteFileExists as FoundationErrorEnum))
+        let fileExists = ((try? self.url(of: toPath).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: toPath).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.cocoaError(toPath, code: .fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
            }
+            self.delegateNotify(operation, error: e)
            return nil
        }
        
-        return self.doOperation(opType, completionHandler: completionHandler)
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.remove(path: path)
-        return self.doOperation(opType, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
-            self.dispatch_queue.async {
-                completionHandler?(self.throwError(toPath, code: CocoaError.fileWriteFileExists as FoundationErrorEnum))
+    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: toPath)
+        
+        let fileExists = ((try? self.url(of: toPath).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: toPath).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.cocoaError(toPath, code: .fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
            }
+            self.delegateNotify(operation, error: e)
            return nil
        }
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        return self.doOperation(opType, forUploading: true, completionHandler: completionHandler)
+        
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
    @discardableResult
-    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
-        return self.doOperation(opType, completionHandler: completionHandler)
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.remove(path: path)
+        return self.doOperation(operation, completionHandler: completionHandler)
    }
    
-    dynamic func doSimpleOperation(_ box: UndoBox) {
+    @discardableResult
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
+        
+        let fileExists = ((try? self.url(of: toPath).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: toPath).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.cocoaError(toPath, code: .fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
+            }
+            self.delegateNotify(operation, error: e)
+            return nil
+        }
+        return self.doOperation(operation, forUploading: true, completionHandler: completionHandler)
+    }
+    
+    @discardableResult
+    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let operation = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
+        return self.doOperation(operation, completionHandler: completionHandler)
+    }
+    
+    @objc dynamic func doSimpleOperation(_ box: UndoBox) {
        guard let _ = self.undoManager else { return }
        _ = self.doOperation(box.undoOperation) { (_) in
            return
@@ -251,7 +290,12 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
    }
    
    @discardableResult
-    fileprivate func doOperation(_ opType: FileOperationType, data: Data? = nil, atomically: Bool = false, forUploading: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    fileprivate func doOperation(_ operation: FileOperationType, data: Data? = nil, atomically: Bool = false, forUploading: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.isCancellable = false
+        progress.setUserInfoObject(Progress.FileOperationKind.receiving, forKey: .fileOperationKindKey)
        
        func urlofpath(path: String) -> URL {
            if path.hasPrefix("file://") {
@@ -263,9 +307,10 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            }
        }
        
-        guard let sourcePath = opType.source else { return nil }
-        let destPath = opType.destination
+        let sourcePath = operation.source
+        let destPath = operation.destination
        let source: URL = urlofpath(path: sourcePath)
+        progress.setUserInfoObject(source, forKey: .fileURLKey)
        
        let dest: URL?
        if let destPath = destPath {
@@ -274,11 +319,11 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            dest = nil
        }
        
-        if let undoManager = self.undoManager, let undoOp = self.undoOperation(for: opType) {
-            let undoBox = UndoBox(provider: self, operation: opType, undoOperation: undoOp)
+        if let undoManager = self.undoManager, let undoOp = self.undoOperation(for: operation) {
+            let undoBox = UndoBox(provider: self, operation: operation, undoOperation: undoOp)
            undoManager.beginUndoGrouping()
            undoManager.registerUndo(withTarget: self, selector: #selector(LocalFileProvider.doSimpleOperation(_:)), object: undoBox)
-            undoManager.setActionName(opType.actionDescription)
+            undoManager.setActionName(operation.actionDescription)
            undoManager.endUndoGrouping()
        }
        
@@ -286,22 +331,31 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
        
        let operationHandler: (URL, URL?) -> Void = { source, dest in
            do {
-                switch opType {
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                switch operation {
                case .create:
                    if sourcePath.hasSuffix("/") {
+                        progress.totalUnitCount = 1
                        try self.opFileManager.createDirectory(at: source, withIntermediateDirectories: true, attributes: [:])
                    } else {
+                        progress.totalUnitCount = Int64(data?.count ?? -1)
                        try data?.write(to: source, options: .atomic)
                    }
                case .modify:
+                    progress.totalUnitCount = Int64(data?.count ?? -1)
                    try data?.write(to: source, options: atomically ? [.atomic] : [])
                case .copy:
                    guard let dest = dest else { return }
+                    progress.setUserInfoObject(Progress.FileOperationKind.copying, forKey: .fileOperationKindKey)
+                    progress.totalUnitCount = abs(source.fileSize)
                    try self.opFileManager.copyItem(at: source, to: dest)
                case .move:
+                    progress.setUserInfoObject(Progress.FileOperationKind.copying, forKey: .fileOperationKindKey)
                    guard let dest = dest else { return }
+                    progress.totalUnitCount = abs(source.fileSize)
                    try self.opFileManager.moveItem(at: source, to: dest)
                case.remove:
+                    progress.totalUnitCount = abs(source.fileSize)
                    try self.opFileManager.removeItem(at: source)
                default:
                    return
@@ -309,30 +363,28 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
                if successfulSecurityScopedResourceAccess {
                    source.stopAccessingSecurityScopedResource()
                }
-                
+
+                progress.completedUnitCount = progress.totalUnitCount
                self.dispatch_queue.async {
                    completionHandler?(nil)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
+                self.delegateNotify(operation)
+            } catch {
                if successfulSecurityScopedResourceAccess {
                    source.stopAccessingSecurityScopedResource()
                }
+                progress.cancel()
                self.dispatch_queue.async {
-                    completionHandler?(e)
-                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
+                    completionHandler?(error)
                }
+                self.delegateNotify(operation, error: error)
            }
        }
        
        if isCoorinating {
            successfulSecurityScopedResourceAccess = source.startAccessingSecurityScopedResource()
            var intents = [NSFileAccessIntent]()
-            switch opType {
+            switch operation {
            case .create, .modify:
                intents.append(NSFileAccessIntent.writingIntent(with: source, options: .forReplacing))
            case .copy:
@@ -348,117 +400,133 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            default:
                return nil
            }
-            self.coordinated(intents: intents, completionHandler: operationHandler, errorHandler: { error in
+            self.coordinated(intents: intents, moving: true, operationHandler: operationHandler, errorHandler: { error in
                self.dispatch_queue.async {
                    completionHandler?(error)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: error)
            })
        } else {
            operation_queue.addOperation {
                operationHandler(source, dest)
            }
        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return progress
    }
    
    @discardableResult
-    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        let opType = FileOperationType.fetch(path: path)
+    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
+        let operation = FileOperationType.fetch(path: path)
        let url = self.url(of: path)
        
+        let progress = Progress(totalUnitCount: url.fileSize)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.isCancellable = false
+        progress.setUserInfoObject(Progress.FileOperationKind.receiving, forKey: .fileOperationKindKey)
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
+        
        let operationHandler: (URL) -> Void = { url in
+            progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
            do {
                let data = try Data(contentsOf: url)
+                progress.completedUnitCount = progress.totalUnitCount
                self.dispatch_queue.async {
                    completionHandler(data, nil)
                }
-            } catch let e {
+                self.delegateNotify(operation)
+            } catch {
+                progress.cancel()
                self.dispatch_queue.async {
-                    completionHandler(nil, e)
+                    completionHandler(nil, error)
                }
+                self.delegateNotify(operation, error: error)
            }
        }
        
        if isCoorinating {
            let intent = NSFileAccessIntent.readingIntent(with: url, options: .withoutChanges)
-            coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
+            coordinated(intents: [intent], operationHandler: operationHandler, errorHandler: { error in
                self.dispatch_queue.async {
                    completionHandler(nil, error)
                }
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: error)
            })
        } else {
            dispatch_queue.async {
                operationHandler(url)
            }
        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+
+        return progress
    }
    
    @discardableResult
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping (_ contents: Data?, _ error: Error?) -> Void) -> Progress? {
        if length == 0 || offset < 0 {
            dispatch_queue.async {
                completionHandler(Data(), nil)
            }
            return nil
        }
-        
+
        if offset == 0 && length < 0 {
            return self.contents(path: path, completionHandler: completionHandler)
        }
-        
-        let opType = FileOperationType.fetch(path: path)
+
+        let operation = FileOperationType.fetch(path: path)
        let url = self.url(of: path)
        
+        let progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(operation, forKey: .fileProvderOperationTypeKey)
+        progress.kind = .file
+        progress.isCancellable = false
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
+        progress.setUserInfoObject(Progress.FileOperationKind.receiving, forKey: .fileOperationKindKey)
+        
        let operationHandler: (URL) -> Void = { url in
-            guard let handle = FileHandle(forReadingAtPath: url.path) else {
-                self.dispatch_queue.async {
-                    completionHandler(nil, self.throwError(path, code: CocoaError.fileNoSuchFile as FoundationErrorEnum))
+            do {
+                guard let handle = FileHandle(forReadingAtPath: url.path) else {
+                    throw self.cocoaError(path, code: .fileNoSuchFile)
                }
-                return
-            }
-            
-            defer {
-                handle.closeFile()
-            }
-            
-            let size = LocalFileObject(fileWithURL: url)?.size ?? -1
-            guard size > offset else {
-                self.dispatch_queue.async {
-                    completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
+                
+                defer {
+                    handle.closeFile()
                }
-                return
-            }
-            handle.seek(toFileOffset: UInt64(offset))
-            guard Int64(handle.offsetInFile) == offset else {
-                self.dispatch_queue.async {
-                    completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
+                
+                let size = LocalFileObject(fileWithURL: url)?.size ?? -1
+                progress.totalUnitCount = size
+                guard size > offset else {
+                    progress.cancel()
+                    throw self.cocoaError(path, code: .fileReadTooLarge)
+                }
+                progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+                handle.seek(toFileOffset: UInt64(offset))
+                guard Int64(handle.offsetInFile) == offset else {
+                    progress.cancel()
+                    throw self.cocoaError(path, code: .fileReadTooLarge)
+                }
+                
+                let data = handle.readData(ofLength: length)
+                progress.completedUnitCount = progress.totalUnitCount
+                self.dispatch_queue.async {
+                    completionHandler(data, nil)
+                    self.delegateNotify(operation)
                }
-                return
            }
-            
-            let data = handle.readData(ofLength: length)
-            
-            self.dispatch_queue.async {
-                completionHandler(data, nil)
+            catch {
+                self.dispatch_queue.async {
+                    completionHandler(nil, error)
+                    self.delegateNotify(operation, error: error)
+                }
            }
        }
        
        if isCoorinating {
            let intent = NSFileAccessIntent.readingIntent(with: url, options: .withoutChanges)
-            coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
+            coordinated(intents: [intent], operationHandler: operationHandler, errorHandler: { error in
                completionHandler(nil, error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
+                self.delegateNotify(operation, error: error)
            })
        } else {
            dispatch_queue.async {
@@ -466,13 +534,24 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
            }
        }
        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return progress
    }
    
    @discardableResult
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.modify(path: path)
-        return self.doOperation(opType, data: data, atomically: atomically, completionHandler: completionHandler)
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
+        let fileExists = ((try? self.url(of: path).checkResourceIsReachable()) ?? false) ||
+            ((try? self.url(of: path).checkPromisedItemIsReachable()) ?? false)
+        if !overwrite && fileExists {
+            let e = self.cocoaError(path, code: .fileWriteFileExists)
+            dispatch_queue.async {
+                completionHandler?(e)
+            }
+            self.delegateNotify(.modify(path: path), error: e)
+            return nil
+        }
+        
+        let operation: FileOperationType = fileExists ? .modify(path: path) : .create(path: path)
+        return self.doOperation(operation, data: data ?? Data(), atomically: atomically, completionHandler: completionHandler)
    }
    
    fileprivate var monitors = [LocalFolderMonitor]()
@@ -506,42 +585,27 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndo
        return monitors.map( { self.relativePathOf(url: $0.url) } ).contains(path.trimmingCharacters(in: CharacterSet(charactersIn: "/")))
    }
    
-    open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = LocalFileProvider(baseURL: self.baseURL!)
-        copy.currentPath = self.currentPath
-        copy.undoManager = self.undoManager
-        copy.isCoorinating = self.isCoorinating
-        copy.delegate = self.delegate
-        copy.fileOperationDelegate = self.fileOperationDelegate
-        return copy
-    }
-}
-
-public extension LocalFileProvider {
    /**
     Creates a symbolic link at the specified path that points to an item at the given path.
-     This method does not traverse symbolic links contained in destURL, making it possible 
-     to create symbolic links to locations that do not yet exist. 
-     Also, if the final path component in url is a symbolic link, that link is not followed.
+     This method does not traverse symbolic links contained in destination path, making it possible
+     to create symbolic links to locations that do not yet exist.
+     Also, if the final path component is a symbolic link, that link is not followed.
    
     - Parameters:
-       - path: The file path at which to create the new symbolic link. The last component of the path issued as the name of the link.
-       - destPath: The path that contains the item to be pointed to by the link. In other words, this is the destination of the link.
+       - symbolicLink: The file path at which to create the new symbolic link. The last component of the path issued as the name of the link.
+       - withDestinationPath: The path that contains the item to be pointed to by the link. In other words, this is the destination of the link.
       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
    */
-    public func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
+    open func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
        operation_queue.addOperation {
+            let operation = FileOperationType.link(link: path, target: destPath)
            do {
                try self.opFileManager.createSymbolicLink(at: self.url(of: path), withDestinationURL: self.url(of: destPath))
                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: .link(link: path, target: destPath))
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: .link(link: path, target: destPath))
-                }
+                self.delegateNotify(operation)
+            } catch {
+                completionHandler?(error)
+                self.delegateNotify(operation, error: error)
            }
        }
    }
@@ -551,32 +615,32 @@ public extension LocalFileProvider {
    /// - Parameters:
    ///   - path: The path of a file or directory.
    ///   - completionHandler: Returns destination url of given symbolic link, or an `Error` object if it fails.
-    public func destination(ofSymbolicLink path: String, completionHandler: @escaping (_ url: URL?, _ error: Error?) -> Void) {
+    open func destination(ofSymbolicLink path: String, completionHandler: @escaping (_ url: URL?, _ error: Error?) -> Void) {
        dispatch_queue.async {
            do {
                let destPath = try self.opFileManager.destinationOfSymbolicLink(atPath: self.url(of: path).path)
                let destUrl = URL(fileURLWithPath: destPath)
                completionHandler(destUrl, nil)
-            } catch let e{
-                completionHandler(nil, e)
+            } catch {
+                completionHandler(nil, error)
            }
        }
    }
 }

 internal extension LocalFileProvider {
-    func coordinated(intents: [NSFileAccessIntent], completionHandler: @escaping (_ url: URL) -> Void, errorHandler: ((_ error: Error) -> Void)? = nil) {
+    func coordinated(intents: [NSFileAccessIntent], operationHandler: @escaping (_ url: URL) -> Void, errorHandler: ((_ error: Error) -> Void)? = nil) {
        let coordinator = NSFileCoordinator(filePresenter: nil)
        coordinator.coordinate(with: intents, queue: operation_queue) { (error) in
            if let error = error {
                errorHandler?(error)
                return
            }
-            completionHandler(intents.first!.url)
+            operationHandler(intents.first!.url)
        }
    }
    
-    func coordinated(intents: [NSFileAccessIntent], moving: Bool = false, completionHandler: @escaping (_ sourceUrl: URL, _ destURL: URL?) -> Void, errorHandler:  ((_ error: Error) -> Void)? = nil) {
+    func coordinated(intents: [NSFileAccessIntent], moving: Bool = false, operationHandler: @escaping (_ sourceUrl: URL, _ destURL: URL?) -> Void, errorHandler:  ((_ error: Error) -> Void)? = nil) {
        let coordinator = NSFileCoordinator(filePresenter: nil)
        coordinator.coordinate(with: intents, queue: operation_queue) { (error) in
            if let error = error {
@@ -588,7 +652,7 @@ internal extension LocalFileProvider {
            if moving, let newDest = newDest {
                coordinator.item(at: newSource, willMoveTo: newDest)
            }
-            completionHandler(newSource, newDest)
+            operationHandler(newSource, newDest)
            if moving, let newDest = newDest {
                coordinator.item(at: newSource, didMoveTo: newDest)
            }
@@ -10,21 +10,19 @@ import Foundation

 /// Containts path, url and attributes of a local file or resource.
 public final class LocalFileObject: FileObject {
-    internal override init(url: URL, name: String, path: String) {
+    internal override init(url: URL?, name: String, path: String) {
        super.init(url: url, name: name, path: path)
    }
    
    /// Initiates a `LocalFileObject` with attributes of file in path.
    public convenience init? (fileWithPath path: String, relativeTo relativeURL: URL?) {
        var fileURL: URL?
-        var rpath = path.replacingOccurrences(of: relativeURL?.path ?? "", with: "", options: .anchored)
-        if relativeURL != nil && rpath.hasPrefix("/") {
-            rpath.remove(at: rpath.startIndex)
-        }
-        if #available(iOS 9.0, macOS 10.11, tvOS 9.0, *) {
+        var rpath = path.replacingOccurrences(of: relativeURL?.path ?? "", with: "", options: .anchored).replacingOccurrences(of: "/", with: "", options: .anchored)
+        if #available(iOS 9.0, macOS 10.11, *) {
            fileURL = URL(fileURLWithPath: rpath, relativeTo: relativeURL)
        } else {
-            fileURL = URL(string: rpath.isEmpty ? "./" : rpath, relativeTo: relativeURL)
+            rpath = rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath
+            fileURL = URL(string: rpath, relativeTo: relativeURL) ?? relativeURL
        }
        
        if let fileURL = fileURL {
@@ -37,7 +35,7 @@ public final class LocalFileObject: FileObject {
    /// Initiates a `LocalFileObject` with attributes of file in url.
    public convenience init?(fileWithURL fileURL: URL) {
        do {
-            let values = try fileURL.resourceValues(forKeys: [.nameKey, .fileSizeKey, .fileAllocatedSizeKey, .creationDateKey, .contentModificationDateKey, .fileResourceTypeKey, .isHiddenKey, .isWritableKey, .typeIdentifierKey, .generationIdentifierKey, .documentIdentifierKey])
+            let values = try fileURL.resourceValues(forKeys: [.nameKey, .fileSizeKey, .totalFileSizeKey, .fileAllocatedSizeKey, .totalFileAllocatedSizeKey, .creationDateKey, .contentModificationDateKey, .fileResourceTypeKey, .isHiddenKey, .isWritableKey, .typeIdentifierKey, .generationIdentifierKey, .documentIdentifierKey])
            let path = fileURL.relativePath.hasPrefix("/") ? fileURL.relativePath : "/" + fileURL.relativePath
            
            self.init(url: fileURL, name: values.name ?? fileURL.lastPathComponent, path: path)
@@ -79,6 +77,16 @@ public final class LocalFileObject: FileObject {
            return data?.map { String(format: "%02hhx", $0) }.joined()
        }
    }
+    
+    /// Count of children items of a driectory. It costs disk access for local directories.
+    open public(set) override var childrensCount: Int? {
+        get {
+            return try? FileManager.default.contentsOfDirectory(atPath: self.url.path).count
+        }
+        set {
+            //
+        }
+    }
 }

 internal final class LocalFolderMonitor {
@@ -216,102 +224,6 @@ internal class LocalFileProviderManagerDelegate: NSObject, FileManagerDelegate {
    }
 }

-/// Local operation handling is limited. Please don't use as much as possible.
-open class LocalOperationHandle: OperationHandle {
-    public let baseURL: URL
-    public let operationType: FileOperationType
-    
-    init (operationType: FileOperationType, baseURL: URL?) {
-        self.baseURL = baseURL ?? URL(fileURLWithPath: "/")
-        self.operationType = operationType
-    }
-    
-    private var sourceURL: URL? {
-        guard let source = operationType.source else { return nil }
-        return source.hasPrefix("file://") ? URL(fileURLWithPath: source) : baseURL.appendingPathComponent(source)
-    }
-    
-    private var destURL: URL? {
-        guard let dest = operationType.destination else { return nil }
-        return dest.hasPrefix("file://") ? URL(fileURLWithPath: dest) : baseURL.appendingPathComponent(dest)
-    }
-    
-    /// Caution: may put pressure on CPU, may have latency
-    open var bytesSoFar: Int64 {
-        assert(!Thread.isMainThread, "Don't run \(#function) method on main thread")
-        switch operationType {
-        case .modify:
-            guard let url = sourceURL, url.isFileURL else { return 0 }
-            if url.fileIsDirectory {
-                return iterateDirectory(url, deep: true).totalsize
-            } else {
-                return url.fileSize
-            }
-        case .copy, .move:
-            guard let url = destURL, url.isFileURL else { return 0 }
-            if url.fileIsDirectory {
-                return iterateDirectory(url, deep: true).totalsize
-            } else {
-                return url.fileSize
-            }
-        default:
-            return 0
-        }
-        
-    }
-    
-    /// Caution: may put pressure on CPU, may have latency
-    open var totalBytes: Int64 {
-        assert(!Thread.isMainThread, "Don't run \(#function) method on main thread")
-        switch operationType {
-        case .copy, .move:
-            guard let url = sourceURL, url.isFileURL else { return 0 }
-            if url.fileIsDirectory {
-                return iterateDirectory(url, deep: true).totalsize
-            } else {
-                return url.fileSize
-            }
-        default:
-            return 0
-        }
-    }
-    
-    /// Not usable in local provider
-    open var inProgress: Bool {
-        return false
-    }
-    
-    /// Not usable in local provider
-    open func cancel() -> Bool{
-        return false
-    }
-    
-    func iterateDirectory(_ pathURL: URL, deep: Bool) -> (folders: Int, files: Int, totalsize: Int64) {
-        var folders = 0
-        var files = 0
-        var totalsize: Int64 = 0
-        let keys: [URLResourceKey] = [.isDirectoryKey, .fileSizeKey]
-        let enumOpt: FileManager.DirectoryEnumerationOptions = !deep ? [.skipsSubdirectoryDescendants, .skipsPackageDescendants] : []
-        
-        let fp = FileManager()
-        let filesList = fp.enumerator(at: pathURL, includingPropertiesForKeys: keys, options: enumOpt, errorHandler: nil)
-        while let fileURL = filesList?.nextObject() as? URL {
-            guard let values = try? fileURL.resourceValues(forKeys: [.isDirectoryKey, .fileSizeKey]) else { continue }
-            let isdir = values.isDirectory ?? false
-            let size = Int64(values.fileSize ?? 0)
-            if isdir {
-                folders += 1
-            } else {
-                files += 1
-            }
-            totalsize += size
-        }
-        
-        return (folders, files, totalsize)
-        
-    }
-}
-
 class UndoBox: NSObject {
    weak var provider: FileProvideUndoable?
    let operation: FileOperationType
@@ -1,455 +0,0 @@
-
-//
-//  OneDriveFileProvider.swift
-//  FileProvider
-//
-//  Created by Amir Abbas Mousavian.
-//  Copyright © 2017 Mousavian. Distributed under MIT license.
-//
-
-import Foundation
-import CoreGraphics
-
-/**
- Allows accessing to OneDrive stored files, either hosted on Microsoft servers or business coprporate one.
- This provider doesn't cache or save files internally, however you can set `useCache` and `cache` properties
- to use Foundation `NSURLCache` system.
- 
- - Note: Uploading files and data are limited to 100MB, for now.
- */
-open class OneDriveFileProvider: FileProviderBasicRemote {
-    open class var type: String { return "OneDrive" }
-    open let baseURL: URL?
-    /// Drive name for user, default is `root`. Changing its value will effect on new operations.
-    open var drive: String
-    /// Generated storage url from server url and drive name
-    open var currentPath: String
-    
-    open var dispatch_queue: DispatchQueue
-    open var operation_queue: OperationQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    
-    open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
-    open private(set) var cache: URLCache?
-    public var useCache: Bool
-    public var validatingCache: Bool
-   
-    fileprivate var _session: URLSession?
-    fileprivate var sessionDelegate: SessionDelegate?
-    public var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let queue = OperationQueue()
-            //queue.underlyingQueue = dispatch_queue
-            let config = URLSessionConfiguration.default
-            config.urlCache = cache
-            config.requestCachePolicy = .returnCacheDataElseLoad
-            _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDelegate?, delegateQueue: queue)
-        }
-        return _session!
-    }
-    
-    /**
-     Initializer for Onedrive provider with given client ID and Token.
-     These parameters must be retrieved via [Authentication for the OneDrive API](https://dev.onedrive.com/auth/readme.htm).
-     
-     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token.
-     The latter is easier to use and prefered. Also you can use [auth0/Lock](https://github.com/auth0/Lock.iOS-OSX) which provides graphical user interface.
-     
-     - Parameters:
-       - credential: a `URLCredential` object with Client ID set as `user` and Token set as `password`.
-       - serverURL: server url, Set it if you are trying to connect OneDrive Business server, otherwise leave it
-         `nil` to connect to OneDrive Personal uses.
-       - drive: drive name for user on server, default value is `root`.
-       - cache: A URLCache to cache downloaded files and contents.
-     */
-    public init(credential: URLCredential?, serverURL: URL? = nil, drive: String = "root", cache: URLCache? = nil) {
-        let baseURL = serverURL ?? URL(string: "https://api.onedrive.com/")!
-        self.baseURL = baseURL.path.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
-        self.drive = drive
-        self.currentPath = ""
-        self.useCache = false
-        self.validatingCache = true
-        self.cache = cache
-        self.credential = credential
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
-        operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
-    }
-    
-    deinit {
-        if fileProviderCancelTasksOnInvalidating {
-            _session?.invalidateAndCancel()
-        } else {
-            _session?.finishTasksAndInvalidate()
-        }
-    }
-    
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
-        list(path) { (contents, cursor, error) in
-            completionHandler(contents, error)
-        }
-    }
-    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
-        var request = URLRequest(url: url(of: path))
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            var fileObject: OneDriveFileObject?
-            if let response = response as? HTTPURLResponse {
-                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
-                if let json = data?.deserializeJSON(), let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: json) {
-                    fileObject = file
-                }
-            }
-            completionHandler(fileObject, serverError ?? error)
-        }) 
-        task.resume()
-    }
-    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
-        var request = URLRequest(url: url())
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var totalSize: Int64 = -1
-            var usedSize: Int64 = 0
-            if let json = data?.deserializeJSON() {
-                totalSize = (json["total"] as? NSNumber)?.int64Value ?? -1
-                usedSize = (json["used"] as? NSNumber)?.int64Value ?? 0
-            }
-            completionHandler(totalSize, usedSize)
-        }) 
-        task.resume()
-    }
-    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
-        var foundFiles = [OneDriveFileObject]()
-        var queryStr: String?
-        queryStr = query.findValue(forKey: "name") as? String ?? query.findAllValues(forKey: nil).flatMap { $0.value as? String }.first
-        guard let finalQueryStr = queryStr else { return }
-        search(path, query: finalQueryStr, foundItem: { (file) in
-            if query.evaluate(with: file.mapPredicate()) {
-                foundFiles.append(file)
-                foundItemHandler?(file)
-            }
-        }, completionHandler: { (error) in
-            completionHandler(foundFiles, error)
-        })
-    }
-    
-    open func url(of path: String? = nil, modifier: String? = nil) -> URL {
-        var rpath: String
-        if let path = path {
-            rpath = path
-        } else {
-            rpath = self.currentPath
-        }
-        
-        if rpath.hasPrefix("/") {
-            rpath.remove(at: rpath.startIndex)
-        }
-        if rpath.isEmpty {
-            if let modifier = modifier {
-                return baseURL!.appendingPathComponent("drive/\(drive)/\(modifier)")
-            }
-            return baseURL!.appendingPathComponent("drive/\(drive)")
-        }
-        let driveURL = baseURL!.appendingPathComponent("drive/\(drive):/")
-        rpath = (rpath.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? rpath)
-        rpath = rpath.trimmingCharacters(in: pathTrimSet)
-        if let modifier = modifier {
-            rpath = rpath + ":/" + modifier
-        }
-        return URL(string: rpath, relativeTo: driveURL) ?? driveURL
-    }
-    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
-        var request = URLRequest(url: url())
-        request.httpMethod = "HEAD"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            let status = (response as? HTTPURLResponse)?.statusCode ?? 400
-            completionHandler(status == 200)
-        })
-        task.resume()
-    }
-    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension OneDriveFileProvider: FileProviderOperations {
-    
-    
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let path = (atPath as NSString).appendingPathComponent(folderName) + "/"
-        return doOperation(.create(path: path), completionHandler: completionHandler)
-    }
-    
-    open func create(file fileName: String, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let filePath = (path as NSString).appendingPathComponent(fileName)
-        return self.writeContents(path: filePath, contents: data ?? Data(), completionHandler: completionHandler)
-    }
-    
-    open func moveItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.move(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func copyItem(path: String, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.copy(source: path, destination: toPath), completionHandler: completionHandler)
-    }
-    
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        return doOperation(.remove(path: path), completionHandler: completionHandler)
-    }
-    
-    fileprivate func doOperation(_ operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: operation) ?? true == true else {
-            return nil
-        }
-        guard let sourcePath = operation.source else { return nil }
-        let destPath = operation.destination
-        var request = URLRequest(url: url(of: sourcePath))
-        switch operation {
-        case .create:
-            request.httpMethod = "CREATE"
-        case .copy:
-            request.httpMethod = "POST"
-        case .move:
-            request.httpMethod = "PATCH"
-        case .remove:
-            request.httpMethod = "DELETE"
-        default: // modify, link, fetch
-            return nil
-        }
-        
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        var requestDictionary = [String: AnyObject]()
-        if let dest = correctPath(destPath) as NSString? {
-            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
-            requestDictionary["parentReference"] = ("/drive/\(drive):" + dest.deletingLastPathComponent) as NSString
-            requestDictionary["name"] = dest.lastPathComponent as NSString
-            request.httpBody = Data(jsonDictionary: requestDictionary)
-        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                 serverError = FileProviderOneDriveError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(serverError ?? error)
-            self.delegateNotify(operation, error: serverError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return upload_simple(toPath, localFile: localFile, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
-    }
-    
-    open func copyItem(path: String, toLocalURL destURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: destURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        var request = URLRequest(url: self.url(of: path, modifier: "content"))
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.downloadTask(with: request, completionHandler: { (cacheURL, response, error) in
-            guard let cacheURL = cacheURL, let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode < 300 else {
-                let code = FileProviderHTTPErrorCode(rawValue: (response as? HTTPURLResponse)?.statusCode ?? -1)
-                let errorData : Data? = nil //Data(contentsOf:cacheURL) // TODO: Figure out how to get error response data for the error description
-                let serverError : FileProviderOneDriveError? = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                completionHandler?(serverError ?? error)
-                return
-            }
-            do {
-                try FileManager.default.moveItem(at: cacheURL, to: destURL)
-                completionHandler?(nil)
-            } catch let e {
-                completionHandler?(e)
-            }
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-}
-
-extension OneDriveFileProvider: FileProviderReadWrite {
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 || offset < 0 {
-            dispatch_queue.async {
-                completionHandler(Data(), nil)
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.fetch(path: path)
-        var request = URLRequest(url: self.url(of: path, modifier: "content"))
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
-        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            if let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: httpResponse.statusCode) {
-                serverError = FileProviderOneDriveError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            let filedata = serverError ?? error == nil ? data : nil
-            completionHandler(filedata, serverError ?? error)
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        // FIXME: remove 150MB restriction
-        return upload_simple(path, data: data, overwrite: overwrite, operation: opType, completionHandler: completionHandler)
-    }
-    
-    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
-        /* There is two ways to monitor folders changing in OneDrive. Either using webooks
-         * which means you have to implement a server to translate it to push notifications
-         * or using apiv2 list_folder/longpoll method. The second one is implemeted here.
-         * Tough webhooks are much more efficient, longpoll is much simpler to implement!
-         * You can implemnt your own webhook service and replace this method accordingly.
-         */
-        NotImplemented()
-    }
-    fileprivate func unregisterNotifcation(path: String) {
-        NotImplemented()
-    }
-    
-    /**
-     Genrates a public url to a file to be shared with other users and can be downloaded without authentication.
-     
-     - Parameters:
-       - to: path of file, including file/directory name.
-       - completionHandler: a closure with result of directory entries or error.
-         `link`: a url returned by OneDrive to share.
-         `attribute`: `nil` for OneDrive.
-         `expiration`: `nil` for OneDrive, as it doesn't expires.
-         `error`: Error returned by OneDrive.
-     */
-    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: OneDriveFileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
-        var request = URLRequest(url: self.url(of: path, modifier: "action.createLink"))
-        request.httpMethod = "POST"
-        let requestDictionary: [String: AnyObject] = ["type": "view" as NSString]
-        request.httpBody = Data(jsonDictionary: requestDictionary)
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            var link: URL?
-            if let response = response as? HTTPURLResponse {
-                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
-                if let json = data?.deserializeJSON() {
-                    if let linkDic = json["link"] as? NSDictionary, let linkStr = linkDic["webUrl"] as? String {
-                        link = URL(string: linkStr)
-                    }
-                }
-            }
-            
-            completionHandler(link, nil, nil, serverError ?? error)
-        })
-        task.resume()
-    }
-}
-
-
-extension OneDriveFileProvider: ExtendedFileProvider {
-    open func thumbnailOfFileSupported(path: String) -> Bool {
-        return true
-    }
-    
-    open func propertiesOfFileSupported(path: String) -> Bool {
-        let fileExt = (path as NSString).pathExtension.lowercased()
-        switch fileExt {
-        case "jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff":
-            return true
-        case "mp3", "aac", "m4a", "wma":
-            return true
-        case "mp4", "mpg", "3gp", "mov", "avi", "wmv":
-            return true
-        default:
-            return false
-        }
-    }
-    
-    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
-        let url: URL
-        if let dimension = dimension {
-            url = self.url(of: path, modifier: "thumbnails/0/=c\(dimension.width)x\(dimension.height)/content")
-        } else {
-            url =  self.url(of: path, modifier: "thumbnails/0/small/content")
-        }
-        
-        var request = URLRequest(url: url)
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = self.session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var image: ImageClass? = nil
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                let responseError = FileProviderOneDriveError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-                completionHandler(nil, responseError)
-                return
-            }
-            if let data = data {
-                image = ImageClass(data: data)
-            }
-            completionHandler(image, error)
-        })
-        task.resume()
-    }
-    
-    open func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String : Any], _ keys: [String], _ error: Error?) -> Void)) {
-        var request = URLRequest(url: url(of: path))
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var serverError: FileProviderOneDriveError?
-            var dic = [String: Any]()
-            var keys = [String]()
-            if let response = response as? HTTPURLResponse {
-                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
-                if let json = data?.deserializeJSON() {
-                    (dic, keys) = self.mapMediaInfo(json)
-                }
-            }
-            completionHandler(dic, keys, serverError ?? error)
-        })
-        task.resume()
-    }
-}
-
-extension OneDriveFileProvider: FileProvider {
-    open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = OneDriveFileProvider(credential: self.credential, serverURL: self.baseURL, drive: self.drive, cache: self.cache)
-        copy.currentPath = self.currentPath
-        copy.delegate = self.delegate
-        copy.fileOperationDelegate = self.fileOperationDelegate
-        copy.useCache = self.useCache
-        copy.validatingCache = self.validatingCache
-        return copy
-    }
-}
@@ -0,0 +1,514 @@
+
+//
+//  OneDriveFileProvider.swift
+//  FileProvider
+//
+//  Created by Amir Abbas Mousavian.
+//  Copyright © 2017 Mousavian. Distributed under MIT license.
+//
+
+import Foundation
+import CoreGraphics
+
+/**
+ Allows accessing to OneDrive stored files, either hosted on Microsoft servers or business coprporate one.
+ This provider doesn't cache or save files internally, however you can set `useCache` and `cache` properties
+ to use Foundation `NSURLCache` system.
+ 
+ - Note: You can pass file id instead of file path, e.g `"id:1234abcd"`, to point to a file or folder by ID.
+ 
+ - Note: Uploading files and data are limited to 100MB, for now.
+ */
+open class OneDriveFileProvider: HTTPFileProvider, FileProviderSharing {
+    override open class var type: String { return "OneDrive" }
+    
+    /// Route to access file container on OneDrive. For default logined user use `.me` otherwise you can acesss
+    /// container based on drive id, group id, site id or user id for another user's default container
+    public enum Route: RawRepresentable {
+        /// Access to default container for current user
+        case me
+        /// Access to a specific drive by id
+        case drive(uuid: UUID)
+        /// Access to a default drive of a group by their id
+        case group(uuid: UUID)
+        /// Access to a default drive of a site by their id
+        case site(uuid: UUID)
+        /// Access to a default drive of a user by their id
+        case user(uuid: UUID)
+        
+        public init?(rawValue: String) {
+            let components = rawValue.components(separatedBy: ";")
+            guard let type = components.first else {
+                return nil
+            }
+            if type == "me" {
+                self = .me
+            }
+            guard let uuid = components.last.flatMap({ UUID(uuidString: $0) }) else {
+                return nil
+            }
+            switch type {
+            case "drive":
+                self = .drive(uuid: uuid)
+            case "group":
+                self = .group(uuid: uuid)
+            case "site":
+                self = .site(uuid: uuid)
+            case "user":
+                self = .user(uuid: uuid)
+            default:
+                return nil
+            }
+        }
+        
+        public var rawValue: String {
+            switch self {
+            case .me:
+                return "me;"
+            case .drive(uuid: let uuid):
+                return "drive;" + uuid.uuidString
+            case .group(uuid: let uuid):
+                return "group;" + uuid.uuidString
+            case .site(uuid: let uuid):
+                return "site;" + uuid.uuidString
+            case .user(uuid: let uuid):
+                return "user;" + uuid.uuidString
+            }
+        }
+        
+        /// Return path component in URL for selected drive
+        var drivePath: String {
+            switch self {
+                case .me:
+                return "me/drive"
+                case .drive(uuid: let uuid):
+                return "drives/" + uuid.uuidString
+                case .group(uuid: let uuid):
+                return "groups/" + uuid.uuidString + "/drive"
+                case .site(uuid: let uuid):
+                return "sites/" + uuid.uuidString + "/drive"
+                case .user(uuid: let uuid):
+                return "users/" + uuid.uuidString + "/drive"
+            }
+        }
+    }
+    /// Route for container, default is `.me`.
+    open let route: Route
+    
+    /**
+     Initializer for Onedrive provider with given client ID and Token.
+     These parameters must be retrieved via [Authentication for the OneDrive API](https://dev.onedrive.com/auth/readme.htm).
+     
+     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token. The latter is easier to use and prefered.
+     
+     - Parameters:
+       - credential: a `URLCredential` object with Client ID set as `user` and Token set as `password`.
+       - serverURL: server url, Set it if you are trying to connect OneDrive Business server, otherwise leave it
+         `nil` to connect to OneDrive Personal user.
+       - drive: drive name for user on server, default value is `root`.
+       - cache: A URLCache to cache downloaded files and contents.
+     */
+    @available(*, deprecated, message: "use init(credential:, serverURL:, route:, cache:) instead.")
+    public init(credential: URLCredential?, serverURL: URL? = nil, drive: String?, cache: URLCache? = nil) {
+        let baseURL = serverURL?.absoluteURL ?? URL(string: "https://api.onedrive.com/")!
+        let refinedBaseURL = baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
+        self.route = drive.flatMap({ UUID(uuidString: $0) }).flatMap({ Route.drive(uuid: $0) }) ?? .me
+        super.init(baseURL: refinedBaseURL, credential: credential, cache: cache)
+    }
+    
+    /**
+     Initializer for Onedrive provider with given client ID and Token.
+     These parameters must be retrieved via [Authentication for the OneDrive API](https://dev.onedrive.com/auth/readme.htm).
+     
+     There are libraries like [p2/OAuth2](https://github.com/p2/OAuth2) or [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) which can facilate the procedure to retrieve token.
+     The latter is easier to use and prefered. Also you can use [auth0/Lock](https://github.com/auth0/Lock.iOS-OSX) which provides graphical user interface.
+     
+     - Parameters:
+       - credential: a `URLCredential` object with Client ID set as `user` and Token set as `password`.
+       - serverURL: server url, Set it if you are trying to connect OneDrive Business server, otherwise leave it
+         `nil` to connect to OneDrive Personal uses.
+       - route: drive name for user on server, default value is `.me`.
+       - cache: A URLCache to cache downloaded files and contents.
+     */
+    public init(credential: URLCredential?, serverURL: URL? = nil, route: Route = .me, cache: URLCache? = nil) {
+        let baseURL = serverURL?.absoluteURL ?? URL(string: "https://api.onedrive.com/")!
+        let refinedBaseURL = baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
+        self.route = route
+        super.init(baseURL: refinedBaseURL, credential: credential, cache: cache)
+    }
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        let route: Route
+        if let driveId = aDecoder.decodeObject(forKey: "drive") as? String, let uuid = UUID(uuidString: driveId) {
+            route = .drive(uuid: uuid)
+        } else {
+            route = (aDecoder.decodeObject(forKey: "route") as? String).flatMap({ Route(rawValue: $0) }) ?? .me
+        }
+        self.init(credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential,
+                  serverURL: aDecoder.decodeObject(forKey: "baseURL") as? URL,
+                  route: route)
+        self.useCache = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
+    }
+    
+    open override func encode(with aCoder: NSCoder) {
+        super.encode(with: aCoder)
+        aCoder.encode(self.route.rawValue, forKey: "route")
+    }
+    
+    open override func copy(with zone: NSZone? = nil) -> Any {
+        let copy = OneDriveFileProvider(credential: self.credential, serverURL: self.baseURL, route: self.route, cache: self.cache)
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        return copy
+    }
+    
+    open override func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
+        _ = paginated(path, requestHandler: { [weak self] (token) -> URLRequest? in
+            guard let `self` = self else { return nil }
+            let url = token.flatMap(URL.init(string:)) ?? self.url(of: path, modifier: "children")
+            var request = URLRequest(url: url)
+            request.httpMethod = "GET"
+            request.set(httpAuthentication: self.credential, with: .oAuth2)
+            return request
+        }, pageHandler: { [weak self] (data, _) -> (files: [FileObject], error: Error?, newToken: String?) in
+            guard let `self` = self else { return ([], nil, nil) }
+            
+            guard let json = data?.deserializeJSON(), let entries = json["value"] as? [AnyObject] else {
+                let err = self.urlError(path, code: .badServerResponse)
+                return ([], err, nil)
+            }
+            
+            var files = [FileObject]()
+            for entry in entries {
+                if let entry = entry as? [String: AnyObject], let file = OneDriveFileObject(baseURL: self.baseURL, route: self.route, json: entry) {
+                    files.append(file)
+                }
+            }
+            return (files, nil, json["@odata.nextLink"] as? String)
+        }, completionHandler: completionHandler)
+    }
+    
+    open override func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
+        var request = URLRequest(url: url(of: path))
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderHTTPError?
+            var fileObject: OneDriveFileObject?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code.flatMap { self.serverError(with: $0, path: path, data: data) }
+                if let json = data?.deserializeJSON(), let file = OneDriveFileObject(baseURL: self.baseURL, route: self.route, json: json) {
+                    fileObject = file
+                }
+            }
+            completionHandler(fileObject, serverError ?? error)
+        }) 
+        task.resume()
+    }
+    
+    open override func storageProperties(completionHandler: @escaping  (_ volumeInfo: VolumeObject?) -> Void) {
+        var request = URLRequest(url: url(of: ""))
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            guard let json = data?.deserializeJSON() else {
+                completionHandler(nil)
+                return
+            }
+            
+            let volume = VolumeObject(allValues: [:])
+            volume.url = request.url
+            volume.name = json["name"] as? String
+            volume.creationDate = (json["createdDateTime"] as? String).flatMap { Date(rfcString: $0) }
+            volume.totalCapacity = (json["quota"]?["total"] as? NSNumber)?.int64Value ?? -1
+            volume.availableCapacity = (json["quota"]?["remaining"] as? NSNumber)?.int64Value ?? 0
+            completionHandler(volume)
+        }) 
+        task.resume()
+    }
+    
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
+        let queryStr = query.findValue(forKey: "name") as? String ?? query.findAllValues(forKey: nil).flatMap { $0.value as? String }.first
+        
+        return paginated(path, requestHandler: { [weak self] (token) -> URLRequest? in
+            guard let `self` = self else { return nil }
+            
+            let url: URL
+            if let next = token.flatMap(URL.init(string:)) {
+                url = next
+            } else {
+                let bURL = self.baseURL!.appendingPathComponent(self.route.drivePath).appendingPathComponent("root/search")
+                var components = URLComponents(url: bURL, resolvingAgainstBaseURL: false)!
+                let qItem = URLQueryItem(name: "q", value: (queryStr ?? "*"))
+                components.queryItems = [qItem]
+                if recursive {
+                    components.queryItems?.append(URLQueryItem(name: "expand", value: "children"))
+                }
+                url = components.url!
+            }
+            
+            var request = URLRequest(url: url)
+            request.httpMethod = "GET"
+            return request
+        }, pageHandler: { [weak self] (data, progress) -> (files: [FileObject], error: Error?, newToken: String?) in
+            guard let `self` = self else { return ([], nil, nil) }
+            guard let json = data?.deserializeJSON(), let entries = json["value"] as? [AnyObject] else {
+                let err = self.urlError(path, code: .badServerResponse)
+                return ([], err, nil)
+            }
+            
+            var foundFiles = [FileObject]()
+            for entry in entries {
+                if let entry = entry as? [String: AnyObject], let file = OneDriveFileObject(baseURL: self.baseURL, route: self.route, json: entry), query.evaluate(with: file.mapPredicate()) {
+                    foundFiles.append(file)
+                    foundItemHandler?(file)
+                }
+            }
+            
+            return (foundFiles, nil, json["@odata.nextLink"] as? String)
+        }, completionHandler: completionHandler)
+    }
+    
+    open func url(of path: String, modifier: String? = nil) -> URL {
+        var url: URL = baseURL!
+        var rpath: String = path
+        let isId = path.hasPrefix("id:")
+        
+        url.appendPathComponent(route.drivePath)
+        
+        if isId {
+            url.appendPathComponent("root:")
+        } else {
+            url.appendPathComponent("items")
+        }
+        
+        rpath = rpath.trimmingCharacters(in: pathTrimSet)
+        
+        switch (modifier == nil, rpath.isEmpty, isId) {
+        case (true, false, _):
+            url.appendPathComponent(rpath)
+        case (true, true, _):
+            break
+        case (false, true, _):
+            url.appendPathComponent(modifier!)
+        case (false, false, true):
+            url.appendPathComponent(rpath)
+            url.appendPathComponent(modifier!)
+        case (false, false, false):
+            url.appendPathComponent(rpath + ":")
+            url.appendPathComponent(modifier!)
+        }
+        
+        return url
+    }
+    
+    open override func isReachable(completionHandler: @escaping (Bool) -> Void) {
+        var request = URLRequest(url: url(of: ""))
+        request.httpMethod = "HEAD"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            let status = (response as? HTTPURLResponse)?.statusCode ?? 400
+            completionHandler(status == 200)
+        })
+        task.resume()
+    }
+    
+    override func request(for operation: FileOperationType, overwrite: Bool = false, attributes: [URLResourceKey : Any] = [:]) -> URLRequest {
+        
+        func correctPath(_ path: String) -> String {
+            if path.hasPrefix("id:") {
+                return path
+            }
+            var p = path.hasPrefix("/") ? path : "/" + path
+            if p.hasSuffix("/") {
+                p.remove(at: p.index(before:p.endIndex))
+            }
+            return p
+        }
+        
+        let method: String
+        let url: URL
+        switch operation {
+        case .fetch(path: let path):
+            method = "GET"
+            url = self.url(of: path, modifier: "content")
+        case .modify(path: let path):
+            method = "PUT"
+            let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
+            url = self.url(of: path, modifier: "content\(queryStr)")
+        case .create(path: let path):
+            method = "CREATE"
+            url = self.url(of: path)
+        case .copy(let source, let dest) where !source.hasPrefix("file://") && !dest.hasPrefix("file://"):
+            method = "POST"
+            url = self.url(of: source)
+        case .copy(let source, let dest) where source.hasPrefix("file://"):
+            method = "PUT"
+            let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
+            url = self.url(of: dest, modifier: "content\(queryStr)")
+        case .copy(let source, let dest) where dest.hasPrefix("file://"):
+            method = "GET"
+            url = self.url(of: source, modifier: "content")
+        case .move(source: let source, destination: _):
+            method = "PATCH"
+            url = self.url(of: source)
+        case .remove(path: let path):
+            method = "DELETE"
+            url = self.url(of: path)
+        default: // link
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
+        }
+        var request = URLRequest(url: url)
+        request.httpMethod = method
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        // Remove gzip to fix availability of progress per (Oleg Marchik)[https://github.com/evilutioner] PR (#61)
+        request.set(httpAcceptEncodings: [.deflate, .identity])
+        
+        switch operation {
+        case .copy(let source, let dest) where !source.hasPrefix("file://") && !dest.hasPrefix("file://"),
+             .move(source: let source, destination: let dest):
+            request.set(httpContentType: .json)
+            let cdest = correctPath(dest) as NSString
+            var parentRefrence: [String: AnyObject] = [:]
+            if cdest.hasPrefix("id:") {
+                parentRefrence["id"] = cdest.components(separatedBy: "/").first as NSString?
+                switch self.route {
+                case .drive(uuid: let uuid):
+                    parentRefrence["driveId"] = uuid.uuidString as NSString
+                default:
+                    break
+                }
+            } else {
+                parentRefrence["path"] = cdest.deletingLastPathComponent as NSString
+            }
+            var requestDictionary = [String: AnyObject]()
+            requestDictionary["parentReference"] = parentRefrence as NSDictionary
+            requestDictionary["name"] = (cdest as NSString).lastPathComponent as NSString
+            request.httpBody = Data(jsonDictionary: requestDictionary)
+        default:
+            break
+        }
+        
+        return request
+    }
+    
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        let errorDesc: String?
+        if let response = data?.deserializeJSON() {
+            errorDesc = response["error"]?["message"] as? String
+        } else {
+            errorDesc = data.flatMap({ String(data: $0, encoding: .utf8) })
+        }
+        return FileProviderOneDriveError(code: code, path: path ?? "", errorDescription: errorDesc)
+    }
+    
+    override var maxUploadSimpleSupported: Int64 {
+        return 104_857_600 // 100MB
+    }
+
+    fileprivate func registerNotifcation(path: String, eventHandler: (() -> Void)) {
+        /* There is two ways to monitor folders changing in OneDrive. Either using webooks
+         * which means you have to implement a server to translate it to push notifications
+         * or using apiv2 list_folder/longpoll method. The second one is implemeted here.
+         * Tough webhooks are much more efficient, longpoll is much simpler to implement!
+         * You can implemnt your own webhook service and replace this method accordingly.
+         */
+        NotImplemented()
+    }
+    fileprivate func unregisterNotifcation(path: String) {
+        NotImplemented()
+    }
+    
+    open func publicLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
+        var request = URLRequest(url: self.url(of: path, modifier: "action.createLink"))
+        request.httpMethod = "POST"
+        let requestDictionary: [String: AnyObject] = ["type": "view" as NSString]
+        request.httpBody = Data(jsonDictionary: requestDictionary)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderHTTPError?
+            var link: URL?
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code.flatMap { self.serverError(with: $0, path: path, data: data) }
+                if let json = data?.deserializeJSON() {
+                    if let linkDic = json["link"] as? NSDictionary, let linkStr = linkDic["webUrl"] as? String {
+                        link = URL(string: linkStr)
+                    }
+                }
+            }
+            
+            completionHandler(link, nil, nil, serverError ?? error)
+        })
+        task.resume()
+    }
+}
+
+
+extension OneDriveFileProvider: ExtendedFileProvider {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
+        return true
+    }
+    
+    open func propertiesOfFileSupported(path: String) -> Bool {
+        let fileExt = (path as NSString).pathExtension.lowercased()
+        switch fileExt {
+        case "jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff":
+            return true
+        case "mp3", "aac", "m4a", "wma":
+            return true
+        case "mp4", "mpg", "3gp", "mov", "avi", "wmv":
+            return true
+        default:
+            return false
+        }
+    }
+    
+    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+        let url: URL
+        if let dimension = dimension {
+            url = self.url(of: path, modifier: "thumbnails/0/=c\(dimension.width)x\(dimension.height)/content")
+        } else {
+            url =  self.url(of: path, modifier: "thumbnails/0/small/content")
+        }
+        
+        var request = URLRequest(url: url)
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = self.session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var image: ImageClass? = nil
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                let responseError = self.serverError(with: rCode, path: path, data: data)
+                completionHandler(nil, responseError)
+                return
+            }
+            if let data = data {
+                image = ImageClass(data: data)
+            }
+            completionHandler(image, error)
+        })
+        task.resume()
+    }
+    
+    open func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String : Any], _ keys: [String], _ error: Error?) -> Void)) {
+        var request = URLRequest(url: url(of: path))
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: .oAuth2)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var serverError: FileProviderHTTPError?
+            var dic = [String: Any]()
+            var keys = [String]()
+            if let response = response as? HTTPURLResponse {
+                let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
+                serverError = code.flatMap { self.serverError(with: $0, path: path, data: data) }
+                if let json = data?.deserializeJSON() {
+                    (dic, keys) = self.mapMediaInfo(json)
+                }
+            }
+            completionHandler(dic, keys, serverError ?? error)
+        })
+        task.resume()
+    }
+}
@@ -18,38 +18,70 @@ public struct FileProviderOneDriveError: FileProviderHTTPError {
 /// Containts path, url and attributes of a OneDrive file or resource.
 public final class OneDriveFileObject: FileObject {
    internal init(baseURL: URL?, name: String, path: String) {
-        var rpath = path
-        if path.hasPrefix("/") {
-            rpath.remove(at: rpath.startIndex)
-        }
-        let url = URL(string: rpath, relativeTo: baseURL) ?? URL(string: path)!
-        super.init(url: url, name: name, path: path)
+        let rpath = (URL(string:path)?.appendingPathComponent(name).absoluteString)!.replacingOccurrences(of: "/", with: "", options: .anchored)
+        let url = URL(string: rpath, relativeTo: baseURL) ?? URL(string: rpath)!
+        
+        super.init(url: url, name: name, path: rpath.removingPercentEncoding ?? path)
    }
    
-    internal convenience init? (baseURL: URL?, drive: String, jsonStr: String) {
+    internal convenience init? (baseURL: URL?, route: OneDriveFileProvider.Route, jsonStr: String) {
        guard let json = jsonStr.deserializeJSON() else { return nil }
-        self.init(baseURL: baseURL, drive: drive, json: json)
+        self.init(baseURL: baseURL, route: route, json: json)
    }
    
-    internal convenience init? (baseURL: URL?, drive: String, json: [String: AnyObject]) {
+    internal convenience init? (baseURL: URL?, route: OneDriveFileProvider.Route, json: [String: AnyObject]) {
        guard let name = json["name"] as? String else { return nil }
-        guard let path = (json["parentReference"] as? NSDictionary)?["path"] as? String else { return nil }
-        var lPath = path.replacingOccurrences(of: "/drive/\(drive)", with: "/", options: .anchored, range: nil)
+        guard let path = json["parentReference"]?["path"] as? String else { return nil }
+        var lPath = path.replacingOccurrences(of: route.drivePath, with: "", options: .anchored, range: nil)
        lPath = lPath.replacingOccurrences(of: "/:", with: "", options: .anchored)
        lPath = lPath.replacingOccurrences(of: "//", with: "", options: .anchored)
        self.init(baseURL: baseURL, name: name, path: lPath)
        self.size = (json["size"] as? NSNumber)?.int64Value ?? -1
-        self.modifiedDate = resolve(dateString: json["lastModifiedDateTime"] as? String ?? "")
-        self.creationDate = resolve(dateString: json["createdDateTime"] as? String ?? "")
-        self.type = (json["folder"] as? String) != nil ? .directory : .regular
+        self.childrensCount = json["folder"]?["childCount"] as? Int
+        self.modifiedDate = (json["lastModifiedDateTime"] as? String).flatMap { Date(rfcString: $0) }
+        self.creationDate = (json["createdDateTime"] as? String).flatMap { Date(rfcString: $0) }
+        self.type = json["folder"] != nil ? .directory : .regular
+        self.contentType = json["file"]?["mimeType"] as? String ?? "application/octet-stream"
        self.id = json["id"] as? String
        self.entryTag = json["eTag"] as? String
+        let hashes = json["file"]?["hashes"] as? NSDictionary
+        // checks for both sha1 or quickXor. First is available in personal drives, second in business one.
+        self.hash = (hashes?["sha1Hash"] as? String) ?? (hashes?["quickXorHash"] as? String)
    }
    
    /// The document identifier is a value assigned by the OneDrive to a file.
    /// This value is used to identify the document regardless of where it is moved on a volume.
-    /// The identifier persists across system restarts.
    open internal(set) var id: String? {
+        get {
+            return allValues[.fileResourceIdentifierKey] as? String
+        }
+        set {
+            allValues[.fileResourceIdentifierKey] = newValue
+        }
+    }
+    
+    /// MIME type of file contents returned by OneDrive server.
+    open internal(set) var contentType: String {
+        get {
+            return allValues[.mimeTypeKey] as? String ?? "application/octet-stream"
+        }
+        set {
+            allValues[.mimeTypeKey] = newValue
+        }
+    }
+    
+    /// HTTP E-Tag, can be used to mark changed files.
+    open internal(set) var entryTag: String? {
+        get {
+            return allValues[.entryTagKey] as? String
+        }
+        set {
+            allValues[.entryTagKey] = newValue
+        }
+    }
+    
+    /// Calculated hash from OneDrive server. Hex string SHA1 in personal or Base65 string [QuickXOR](https://dev.onedrive.com/snippets/quickxorhash.htm) in business drives.
+    open internal(set) var hash: String? {
        get {
            return allValues[.documentIdentifierKey] as? String
        }
@@ -57,152 +89,8 @@ public final class OneDriveFileObject: FileObject {
            allValues[.documentIdentifierKey] = newValue
        }
    }
-    
-    /// MIME type of file contents returned by OneDrive server.
-    open internal(set) var contentType: String {
-        get {
-            return allValues[.mimeType] as? String ?? ""
-        }
-        set {
-            allValues[.mimeType] = newValue
-        }
-    }
-    
-    /// HTTP E-Tag, can be used to mark changed files.
-    open internal(set) var entryTag: String? {
-        get {
-            return allValues[.entryTag] as? String
-        }
-        set {
-            allValues[.entryTag] = newValue
-        }
-    }
 }

-// codebeat:disable[ARITY]
-internal extension OneDriveFileProvider {
-    func list(_ path: String, cursor: URL? = nil, prevContents: [OneDriveFileObject] = [], completionHandler: @escaping ((_ contents: [FileObject], _ cursor: String?, _ error: Error?) -> Void)) {
-        let url = cursor ?? self.url(of: path, modifier: "children")
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderOneDriveError?
-            var files = prevContents
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderOneDriveError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            if let json = data?.deserializeJSON() {
-                if let entries = json["value"] as? [AnyObject] , entries.count > 0 {
-                    for entry in entries {
-                        if let entry = entry as? [String: AnyObject], let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: entry) {
-                            files.append(file)
-                        }
-                    }
-                    let ncursor: URL? = (json["@odata.nextLink"] as? String).flatMap { URL(string: $0) }
-                    let hasmore = ncursor != nil
-                    if hasmore {
-                        self.list(path, cursor: ncursor, prevContents: files, completionHandler: completionHandler)
-                        return
-                    }
-                }
-            }
-            completionHandler(files, nil, responseError ?? error)
-        })
-        task.taskDescription = FileOperationType.fetch(path: path).json
-        task.resume()
-    }
-    
-    func upload_simple(_ targetPath: String, data: Data, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        if data.count > 100 * 1024 * 1024 {
-            let error = FileProviderOneDriveError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
-        let url = self.url(of: targetPath, modifier: "content\(queryStr)")
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        request.httpBody = data
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderOneDriveError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderOneDriveError(code: rCode, path: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(operation, error: responseError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    func upload_simple(_ targetPath: String, localFile: URL, modifiedDate: Date = Date(), overwrite: Bool, operation: FileOperationType, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let size = (try? localFile.resourceValues(forKeys: [.fileSizeKey]))?.fileSize ?? -1
-        if size > 100 * 1024 * 1024 {
-            let error = FileProviderOneDriveError(code: .payloadTooLarge, path: targetPath, errorDescription: nil)
-            completionHandler?(error)
-            self.delegateNotify(.create(path: targetPath), error: error)
-            return nil
-        }
-        let queryStr = overwrite ? "" : "?@name.conflictBehavior=fail"
-        let url = self.url(of: targetPath, modifier: "content\(queryStr)")
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
-            var responseError: FileProviderOneDriveError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderOneDriveError(code: rCode, path: targetPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(operation, error: responseError ?? error)
-        })
-        task.taskDescription = operation.json
-        task.resume()
-        return RemoteOperationHandle(operationType: operation, tasks: [task])
-    }
-    
-    func search(_ startPath: String = "", query: String, next: URL? = nil, foundItem:@escaping ((_ file: OneDriveFileObject) -> Void), completionHandler: @escaping ((_ error: Error?) -> Void)) {
-        let url: URL
-        let q = query.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
-        url = next ?? self.url(of: startPath, modifier: "view.search?q=\(q)")
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
-        
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderOneDriveError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderOneDriveError(code: rCode, path: startPath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
-            }
-            if let json = data?.deserializeJSON() {
-                if let entries = json["value"] as? [AnyObject] , entries.count > 0 {
-                    for entry in entries {
-                        if let entry = entry as? [String: AnyObject], let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: entry) {
-                            foundItem(file)
-                        }
-                    }
-                    let next: URL? = (json["@odata.nextLink"] as? String).flatMap { URL(string: $0) }
-                    if let next = next {
-                        self.search(startPath, query: query, next: next, foundItem: foundItem, completionHandler: completionHandler)
-                    } else {
-                        completionHandler(responseError ?? error)
-                    }
-                    return
-                }
-            }
-            completionHandler(responseError ?? error)
-        }) 
-        task.resume()
-    }
-}
-// codebeat:enable[ARITY]
-
 internal extension OneDriveFileProvider {
    static let dateFormatter = DateFormatter()
    static let decimalFormatter = NumberFormatter()
@@ -240,14 +128,14 @@ internal extension OneDriveFileProvider {
        if let location = json["location"] as? [String: Any], let latitude = location["latitude"] as? Double, let longitude = location["longitude"] as? Double {
            OneDriveFileProvider.decimalFormatter.numberStyle = .decimal
            OneDriveFileProvider.decimalFormatter.maximumFractionDigits = 5
-            let latStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))
-            let longStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))
+            let latStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))!
+            let longStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))!
            add(key: "Location", value: "\(latStr), \(longStr)")
        }
        if let parent = json["image"] as? [String: Any] ?? json["video"] as? [String: Any], let duration = parent["duration"] as? UInt64 {
            add(key: "Duration", value: (TimeInterval(duration) / 1000).formatshort)
        }
-        if let timeTakenStr = json["takenDateTime"] as? String, let timeTaken = resolve(dateString: timeTakenStr) {
+        if let timeTakenStr = json["takenDateTime"] as? String, let timeTaken = Date(rfcString: timeTakenStr) {
            OneDriveFileProvider.dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
            add(key: "Date taken", value:  OneDriveFileProvider.dateFormatter.string(from: timeTaken))
        }
@@ -275,14 +163,4 @@ internal extension OneDriveFileProvider {
        
        return (dic, keys)
    }
-    
-    func delegateNotify(_ operation: FileOperationType, error: Error?) {
-        DispatchQueue.main.async(execute: {
-            if error == nil {
-                self.delegate?.fileproviderSucceed(self, operation: operation)
-            } else {
-                self.delegate?.fileproviderFailed(self, operation: operation)
-            }
-        })
-    }
 }
@@ -8,63 +8,11 @@

 import Foundation

-/// Allows to get progress or cancel an in-progress operation, for remote, `URLSession` based providers.
-open class RemoteOperationHandle: OperationHandle {
-    
-    internal var tasks: [Weak<URLSessionTask>]
-    
-    open private(set) var operationType: FileOperationType
-    
-    init(operationType: FileOperationType, tasks: [URLSessionTask]) {
-        self.operationType = operationType
-        self.tasks = tasks.map { Weak<URLSessionTask>($0) }
-    }
-    
-    internal func add(task: URLSessionTask) {
-        tasks.append(Weak<URLSessionTask>(task))
-    }
-    
-    private func reape() {
-        self.tasks = tasks.filter { $0.value != nil }
-    }
-    
-    open var bytesSoFar: Int64 {
-        return tasks.reduce(0) {
-            if let task = $1.value as? URLSessionUploadTask {
-                return $0 + task.countOfBytesSent
-            } else {
-                return $0 + ($1.value?.countOfBytesReceived ?? 0)
-            }
-        }
-    }
-    
-    open var totalBytes: Int64 {
-        return tasks.reduce(0) {
-            if let task = $1.value as? URLSessionUploadTask {
-                return $0 + task.countOfBytesExpectedToSend
-            } else {
-                return $0 + ($1.value?.countOfBytesExpectedToReceive ?? 0)
-            }
-        }
-    }
-    
-    open func cancel() -> Bool {
-        var canceled = false
-        for taskbox in tasks {
-            taskbox.value?.cancel()
-            canceled = true
-        }
-        return canceled
-    }
-    
-    open var inProgress: Bool {
-        return tasks.reduce(false) { $0 || $1.value?.state ?? .canceling == .running }
-    }
-}
-
 /// A protocol defines properties for errors returned by HTTP/S based providers.
 /// Including Dropbox, OneDrive and WebDAV.
 public protocol FileProviderHTTPError: Error, CustomStringConvertible {
+    /// HTTP status codes as an enum.
+    typealias Code = FileProviderHTTPErrorCode
    /// HTTP status code returned for error by server.
    var code: FileProviderHTTPErrorCode { get }
    /// Path of file/folder casued that error
@@ -77,57 +25,181 @@ extension FileProviderHTTPError {
    public var description: String {
        return code.description
    }
+    
+    public var localizedDescription: String {
+        return description
+    }
 }

-class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDelegate {
+internal var completionHandlersForTasks = [String: [Int: SimpleCompletionHandler]]()
+internal var downloadCompletionHandlersForTasks = [String: [Int: (URL) -> Void]]()
+internal var dataCompletionHandlersForTasks = [String: [Int: (Data) -> Void]]()
+internal var responseCompletionHandlersForTasks = [String: [Int: (URLResponse) -> Void]]()
+
+internal func initEmptySessionHandler(_ uuid: String) {
+    completionHandlersForTasks[uuid] = [:]
+    downloadCompletionHandlersForTasks[uuid] = [:]
+    dataCompletionHandlersForTasks[uuid] = [:]
+}
+
+internal func removeSessionHandler(for uuid: String) {
+    _ = completionHandlersForTasks.removeValue(forKey: uuid)
+    _ = downloadCompletionHandlersForTasks.removeValue(forKey: uuid)
+    _ = dataCompletionHandlersForTasks.removeValue(forKey: uuid)
+}
+
+/// All objects set to `FileProviderRemote.session` must be an instance of this class
+final public class SessionDelegate: NSObject, URLSessionDataDelegate, URLSessionDownloadDelegate, URLSessionStreamDelegate {
    
-    weak var fileProvider: FileProvider?
+    weak var fileProvider: (FileProviderBasicRemote & FileProviderOperations)?
    var credential: URLCredential?
    
-    var finishDownloadHandler: ((_ session: Foundation.URLSession, _ downloadTask: URLSessionDownloadTask, _ didFinishDownloadingToURL: URL) -> Void)?
-    var didSendDataHandler: ((_ session: Foundation.URLSession, _ task: URLSessionTask, _ bytesSent: Int64, _ totalBytesSent: Int64, _ totalBytesExpectedToSend: Int64) -> Void)?
-    var didReceivedData: ((_ session: Foundation.URLSession, _ downloadTask: URLSessionDownloadTask, _ bytesWritten: Int64, _ totalBytesWritten: Int64, _ totalBytesExpectedToWrite: Int64) -> Void)?
-    
-    init(fileProvider: FileProvider, credential: URLCredential?) {
+    public init(fileProvider: FileProviderBasicRemote & FileProviderOperations) {
        self.fileProvider = fileProvider
-        self.credential = credential
+        self.credential = fileProvider.credential
+    }
+    
+    open override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
+        if let progress = context?.load(as: Progress.self), let newVal = change?[.newKey] as? Int64 {
+            switch keyPath ?? "" {
+            case #keyPath(URLSessionTask.countOfBytesReceived):
+                progress.completedUnitCount = newVal
+                if let startTime = progress.userInfo[ProgressUserInfoKey.startingTimeKey] as? Date, let task = object as? URLSessionTask {
+                    let elapsed = Date().timeIntervalSince(startTime)
+                    let throughput = Double(newVal) / elapsed
+                    progress.setUserInfoObject(NSNumber(value: throughput), forKey: .throughputKey)
+                    if task.countOfBytesExpectedToReceive > 0 {
+                        let remain = task.countOfBytesExpectedToReceive - task.countOfBytesReceived
+                        let estimatedTimeRemaining = Double(remain) / elapsed
+                        progress.setUserInfoObject(NSNumber(value: estimatedTimeRemaining), forKey: .estimatedTimeRemainingKey)
+                    }
+                }
+            case #keyPath(URLSessionTask.countOfBytesSent):
+                progress.completedUnitCount = newVal
+                if let startTime = progress.userInfo[ProgressUserInfoKey.startingTimeKey] as? Date, let task = object as? URLSessionTask {
+                    let elapsed = Date().timeIntervalSince(startTime)
+                    let throughput = Double(newVal) / elapsed
+                    progress.setUserInfoObject(NSNumber(value: throughput), forKey: .throughputKey)
+                    if task.countOfBytesExpectedToSend > 0 {
+                        let remain = task.countOfBytesExpectedToSend - task.countOfBytesSent
+                        let estimatedTimeRemaining = Double(remain) / elapsed
+                        progress.setUserInfoObject(NSNumber(value: estimatedTimeRemaining), forKey: .estimatedTimeRemainingKey)
+                    }
+                }
+            case #keyPath(URLSessionTask.countOfBytesExpectedToReceive), #keyPath(URLSessionTask.countOfBytesExpectedToSend):
+                progress.totalUnitCount = newVal
+            default:
+                super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
+            }
+        }
    }
    
    // codebeat:disable[ARITY]
-    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
-        self.finishDownloadHandler?(session, downloadTask, location)
-        return
+    public func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
+        if task is URLSessionUploadTask {
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesSent))
+            //task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToSend))
+        } else if task is URLSessionDownloadTask {
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived))
+            task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive))
+        }
+        
+        _ = dataCompletionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: task.taskIdentifier)
+        if !(error == nil && task is URLSessionDownloadTask) {
+            let completionHandler = completionHandlersForTasks[session.sessionDescription!]?[task.taskIdentifier] ?? nil
+            completionHandler?(error)
+            _ = completionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: task.taskIdentifier)
+        }
+        
+        guard let json = task.taskDescription?.deserializeJSON(),
+            let op = FileOperationType(json: json), let fileProvider = fileProvider else {
+                return
+        }
+        
+        switch op {
+        case .fetch:
+            if task is URLSessionDataTask {
+                task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesReceived))
+                task.removeObserver(self, forKeyPath: #keyPath(URLSessionTask.countOfBytesExpectedToReceive))
+            }
+        default:
+            break
+        }
+        
+        if !(task is URLSessionDownloadTask), case FileOperationType.fetch = op {
+            return
+        }
+        if #available(iOS 9.0, macOS 10.11, *) {
+            if task is URLSessionStreamTask {
+                return
+            }
+        }
+        
+        fileProvider.delegateNotify(op, error: error)
    }
    
-    func urlSession(_ session: URLSession, task: URLSessionTask, didSendBodyData bytesSent: Int64, totalBytesSent: Int64, totalBytesExpectedToSend: Int64) {
-        self.didSendDataHandler?(session, task, bytesSent, totalBytesSent, totalBytesExpectedToSend)
+    public func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
+        let dcompletionHandler = downloadCompletionHandlersForTasks[session.sessionDescription!]?[downloadTask.taskIdentifier]
+        dcompletionHandler?(location)
+        _ = downloadCompletionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: downloadTask.taskIdentifier)
+        _ = completionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: downloadTask.taskIdentifier)
+    }
+    
+    public func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive response: URLResponse, completionHandler: @escaping (URLSession.ResponseDisposition) -> Void) {
+        let handler = responseCompletionHandlersForTasks[session.sessionDescription!]?[dataTask.taskIdentifier] ?? nil
+        handler?(response)
+        completionHandler(.allow)
+        _ = responseCompletionHandlersForTasks[session.sessionDescription!]?.removeValue(forKey: dataTask.taskIdentifier)
+    }
+    
+    public func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
+        if let completionHandler = dataCompletionHandlersForTasks[session.sessionDescription!]?[dataTask.taskIdentifier] {
+            if let json = dataTask.taskDescription?.deserializeJSON(),
+               let op = FileOperationType(json: json), let fileProvider = fileProvider {
+                fileProvider.delegateNotify(op, progress: Double(dataTask.countOfBytesReceived) / Double(dataTask.countOfBytesExpectedToReceive))
+            }
+            completionHandler(data)
+        }
        
+    }
+    
+    public func urlSession(_ session: URLSession, task: URLSessionTask, didSendBodyData bytesSent: Int64, totalBytesSent: Int64, totalBytesExpectedToSend: Int64) {
        guard let json = task.taskDescription?.deserializeJSON(),
              let op = FileOperationType(json: json), let fileProvider = fileProvider else {
            return
        }
        
-        let progress = Float(totalBytesSent) / Float(totalBytesExpectedToSend)
+        switch op {
+        case .create(path: let path):
+            if path.hasSuffix("/") { return }
+            break
+        case .modify:
+            break
+        case .copy(source: let source, destination: _) where source.hasPrefix("file://"):
+            break
+        default:
+            return
+        }
        
-        fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, progress: progress)
+        fileProvider.delegateNotify(op, progress: Double(totalBytesSent) / Double(totalBytesExpectedToSend))
    }
    
-    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
-        self.didReceivedData?(session, downloadTask, bytesWritten, totalBytesWritten, totalBytesExpectedToWrite)
+    public func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
+        if totalBytesExpectedToWrite == NSURLSessionTransferSizeUnknown { return }
        
        guard let json = downloadTask.taskDescription?.deserializeJSON(),
              let op = FileOperationType(json: json), let fileProvider = fileProvider else {
            return
        }
        
-        fileProvider.delegate?.fileproviderProgress(fileProvider, operation: op, progress: Float(totalBytesWritten) / Float(totalBytesExpectedToWrite))
+        fileProvider.delegateNotify(op, progress: Double(totalBytesWritten) / Double(totalBytesExpectedToWrite))
    }
    
-    func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+    public func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        authenticate(didReceive: challenge, completionHandler: completionHandler)
    }
    
-    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+    public func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        authenticate(didReceive: challenge, completionHandler: completionHandler)
    }
    
@@ -286,6 +358,10 @@ public enum FileProviderHTTPErrorCode: Int, CustomStringConvertible {
        }
    }
    
+    public var localizedDescription: String {
+        return HTTPURLResponse.localizedString(forStatusCode: self.rawValue)
+    }
+    
    /// Description of status based on first digit which indicated fail or success.
    public var typeDescription: String {
        switch self.rawValue {
@@ -11,11 +11,11 @@ import Foundation
 // This client implementation is for little-endian platform, namely x86, x64 & arm
 // For big-endian platforms like PowerPC, there must be a huge overhaul

-protocol SMBProtocolClientDelegate: class {
-    func receivedResponse(client: SMB2ProtocolClient, response: SMBResponse, for: SMBRequest)
+protocol FileProviderSMBTaskDelegate: class {
+    func receivedResponse(client: FileProviderSMBTask, response: SMBResponse, for: SMBRequest)
 }

-class SMB2ProtocolClient: FPSStreamTask {
+class FileProviderSMBTask: FileProviderStreamTask {
    var timeout: TimeInterval = 30
    
    private(set) var lastMessageID: UInt64 = 0
@@ -31,14 +31,14 @@ class SMB2ProtocolClient: FPSStreamTask {
    private(set) var requestStack = [Int: SMBRequest]()
    private(set) var responseStack = [Int: SMBResponse]()
    
-    weak var delegate: SMBProtocolClientDelegate?
+    weak var delegate: FileProviderSMBTaskDelegate?
    
    func sendNegotiate(completionHandler: SimpleCompletionHandler) -> UInt64 {
        let mId = messageId()
        let smbHeader = SMB2.Header(command: .NEGOTIATE, creditRequestResponse: UInt16(126), messageId: mId, treeId: UInt32(0), sessionId: UInt64(0))
        let msg = SMB2.NegotiateRequest()
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
        })
        return mId
@@ -50,9 +50,9 @@ class SMB2ProtocolClient: FPSStreamTask {
        let smbHeader = SMB2.Header(command: SMB2.Command.SESSION_SETUP, creditRequestResponse: credit, messageId: mId, treeId: UInt32(0), sessionId: sessionId)
        let msg = SMB2.SessionSetupRequest(singing: [])
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            if self.sessionId == 0 {
-                self.readData(OfMinLength: 64, maxLength: 65536, timeout: self.timeout, completionHandler: { (data, eof, e2) in
+                self.readData(ofMinLength: 64, maxLength: 65536, timeout: self.timeout, completionHandler: { (data, eof, e2) in
                    // TODO: set session id
                    completionHandler?(e2 ?? e)
                })
@@ -73,7 +73,7 @@ class SMB2ProtocolClient: FPSStreamTask {
        let tcHeader = SMB2.TreeConnectRequest.Header(flags: [])
        let msg = SMB2.TreeConnectRequest(header: tcHeader, host: host, share: share)
        let data = createSMB2Message(header: smbHeader, message: msg!)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
            
        })
@@ -85,7 +85,7 @@ class SMB2ProtocolClient: FPSStreamTask {
        let smbHeader = SMB2.Header(command: .TREE_DISCONNECT, creditRequestResponse: 111, messageId: mId, treeId: treeId, sessionId: sessionId)
        let msg = SMB2.TreeDisconnect()
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
        })
        return mId
@@ -96,7 +96,7 @@ class SMB2ProtocolClient: FPSStreamTask {
        let smbHeader = SMB2.Header(command: .LOGOFF, creditRequestResponse: 0, messageId: mId, treeId: 0, sessionId: sessionId)
        let msg = SMB2.LogOff()
        let data = createSMB2Message(header: smbHeader, message: msg)
-        self.writeData(data, timeout: 0, completionHandler: { (e) in
+        self.write(data, timeout: timeout, completionHandler: { (e) in
            completionHandler?(e)
        })
        return mId
@@ -108,7 +108,7 @@ class SMB2ProtocolClient: FPSStreamTask {
 }

 // MARK: create and analyse messages
-extension SMB2ProtocolClient {
+extension FileProviderSMBTask {
    func determineSMBVersion(_ data: Data) -> Float {
        let smbverChar: Int8 = Int8(bitPattern: data.first ?? 0)
        let version = 0 - smbverChar
@@ -138,7 +138,8 @@ extension SMB2ProtocolClient {
            let paramData = Data(bytesNoCopy: UnsafeMutablePointer<UInt8>(&rawParamWords), count: rawParamWords.count, deallocator: .free)
            paramWords = paramData.scanValue()!
            offset += paramWordsCount * 2
-            let messageBytesCount = Int(UInt16(buffer[0]) + UInt16(buffer[1]) << 8)
+            let messageBytesCountHi = Int(buffer[1]) << 8
+            let messageBytesCount = Int(buffer[0]) + messageBytesCountHi
            offset += MemoryLayout<UInt16>.size
            guard data.count >= (offset + messageBytesCount) else {
                throw SMBFileProviderError.incorrectMessageLength
@@ -15,31 +15,56 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
    open var dispatch_queue: DispatchQueue
    open var operation_queue: OperationQueue
    open weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
+    open var credential: URLCredential?
    
    public typealias FileObjectClass = FileObject
    
-    public init? (baseURL: URL, credential: URLCredential, afterInitialized: SimpleCompletionHandler) {
+    public init? (baseURL: URL, credential: URLCredential?) {
        guard baseURL.uw_scheme.lowercased() == "smb" else {
            return nil
        }
        self.baseURL = baseURL.appendingPathComponent("")
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
+        
+        #if swift(>=3.1)
+        let queueLabel = "FileProvider.\(Swift.type(of: self).type)"
+        #else
+        let queueLabel = "FileProvider.\(type(of: self).type)"
+        #endif
+        dispatch_queue = DispatchQueue(label: queueLabel, attributes: .concurrent)
        operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
+        operation_queue.name = "\(queueLabel).Operation"
        
        self.credential = credential
    }
-        
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObjectClass], _ error: Error?) -> Void)) {
+    
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else {
+            return nil
+        }
+        self.init(baseURL: baseURL,
+                  credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.currentPath   = aDecoder.decodeObject(forKey: "currentPath") as? String ?? ""
+    }
+    
+    open func encode(with aCoder: NSCoder) {
+        aCoder.encode(self.baseURL, forKey: "baseURL")
+        aCoder.encode(self.credential, forKey: "credential")
+        aCoder.encode(self.currentPath, forKey: "currentPath")
+    }
+    
+    public static var supportsSecureCoding: Bool {
+        return true
+    }
+    
+    open func contentsOfDirectory(path: String, completionHandler: @escaping (_ contents: [FileObjectClass], _ error: Error?) -> Void) {
        NotImplemented()
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObjectClass?, _ error: Error?) -> Void)) {
+    open func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObjectClass?, _ error: Error?) -> Void) {
        NotImplemented()
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+    open func storageProperties(completionHandler: @escaping (_ volume: VolumeObject?) -> Void) {
        NotImplemented()
    }
    
@@ -49,60 +74,56 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
    
    open weak var fileOperationDelegate: FileOperationDelegate?
    
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
+    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
+    open func writeContents(path: String, contents data: Data?, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler:((FileObjectClass) -> Void)?, completionHandler: @escaping ((_ files: [FileObjectClass], _ error: Error?) -> Void)) -> Progress? {
        NotImplemented()
        return nil
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler:((FileObjectClass) -> Void)?, completionHandler: @escaping ((_ files: [FileObjectClass], _ error: Error?) -> Void)) {
-        NotImplemented()
-    }
-    
    open func registerNotifcation(path: String, eventHandler: @escaping (() -> Void)) {
        NotImplemented()
    }
@@ -116,7 +137,7 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
    }
    
    open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = SMBFileProvider(baseURL: self.baseURL!, credential: self.credential!, afterInitialized: { _ in })!
+        let copy = SMBFileProvider(baseURL: self.baseURL!, credential: self.credential!)!
        copy.currentPath = self.currentPath
        copy.delegate = self.delegate
        copy.fileOperationDelegate = self.fileOperationDelegate
@@ -8,6 +8,7 @@

 import Foundation

+// codebeat:disable[TOO_MANY_IVARS]
 // SMB/CIFS Types
 struct SMB1 {
    struct Header { // 32 bytes
@@ -75,6 +76,7 @@ struct SMB1 {
            }
        }
        
+        // codebeat:disable[ARITY]
        init(command: Command, treeId: UInt16, pid: UInt32, userId: UInt16, multiplexId: UInt16, flags: Flags, flags2: Flags2 = [.LONG_NAMES, .ERR_STATUS, .UNICODE], ntStatus: UInt32 = 0, securityKey: UInt32 = 0, securityCID: UInt16 = 0, securitySequenceNumber: UInt16 = 0) {
            self.protocolID = Header.protocolConst
            self._command = command.rawValue
@@ -91,6 +93,7 @@ struct SMB1 {
            self.userId = userId
            self.multiplexId = multiplexId
        }
+        // codebeat:enable[ARITY]
    }
    
    struct Flags: OptionSet {
@@ -215,3 +218,4 @@ struct SMB1 {
        case INVALID                = 0xFE
    }
 }
+// codebeat:enable[TOO_MANY_IVARS]
@@ -64,7 +64,10 @@ extension SMB2 {
            var contextCount: UInt16
            fileprivate let reserved2: UInt16
            var clientStartTime: SMBTime {
-                let time = Int64(contextOffset) + (Int64(contextCount) << 32) + (Int64(contextCount) << 48)
+                let lo = Int64(contextOffset)
+                let hi1 = Int64(contextCount) << 32
+                let hi2 = Int64(contextCount) << 48
+                let time: Int64 = lo + hi1 + hi2
                return SMBTime(time: time)
            }
            
@@ -26,7 +26,7 @@ extension SMB2 {
                return nil
            }
            self.header = header
-            let path = "\\\\\(host)\\\(share)"
+            let path = "\\\\" + host + "\\" + share
            self.buffer = path.data(using: .utf16)
        }
        
@@ -7,50 +7,25 @@
 //

 import Foundation
+import CoreGraphics

 /**
 Allows accessing to WebDAV server files. This provider doesn't cache or save files internally, however you can
 set `useCache` and `cache` properties to use Foundation `NSURLCache` system.
 
- WebDAV system supported by many cloud services including [Box.net](https://www.box.com/home) 
+ WebDAV system supported by many cloud services including [Box.com](https://www.box.com/home) 
 and [Yandex disk](https://disk.yandex.com) and [ownCloud](https://owncloud.org).
 
 - Important: Because this class uses `URLSession`, it's necessary to disable App Transport Security
     in case of using this class with unencrypted HTTP connection.
     [Read this to know how](http://iosdevtips.co/post/121756573323/ios-9-xcode-7-http-connect-server-error).
 */
-open class WebDAVFileProvider: FileProviderBasicRemote {
-    open class var type: String { return "WebDAV" }
-    open let baseURL: URL?
-    open var currentPath: String
+open class WebDAVFileProvider: HTTPFileProvider, FileProviderSharing {
+    override open class var type: String { return "WebDAV" }
    
-    open var dispatch_queue: DispatchQueue
-    open var operation_queue: OperationQueue {
-        willSet {
-            assert(_session == nil, "It's not effective to change dispatch_queue property after session is initialized.")
-        }
-    }
-    
-    public weak var delegate: FileProviderDelegate?
-    open let credential: URLCredential?
-    open private(set) var cache: URLCache?
-    public var useCache: Bool
-    public var validatingCache: Bool
-    
-    fileprivate var _session: URLSession?
-    fileprivate var sessionDelegate: SessionDelegate?
-    public var session: URLSession {
-        if _session == nil {
-            self.sessionDelegate = SessionDelegate(fileProvider: self, credential: credential)
-            let queue = OperationQueue()
-            //queue.underlyingQueue = dispatch_queue
-            let config = URLSessionConfiguration.default
-            config.urlCache = cache
-            config.requestCachePolicy = .returnCacheDataElseLoad
-            _session = URLSession(configuration: config, delegate: sessionDelegate as URLSessionDownloadDelegate?, delegateQueue: queue)
-        }
-        return _session!
-    }
+    /// An enum which defines HTTP Authentication method, usually you should it default `.digest`.
+    /// If the server uses OAuth authentication, credential must be set with token as `password`, like Dropbox.
+    public var credentialType: URLRequest.AuthenticationType = .digest
    
    /**
     Initializes WebDAV provider.
@@ -64,65 +39,77 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        if  !["http", "https"].contains(baseURL.uw_scheme.lowercased()) {
            return nil
        }
-        self.baseURL = baseURL.path.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent("")
-        self.currentPath = ""
-        self.useCache = false
-        self.validatingCache = true
-        self.cache = cache
-        self.credential = credential
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
-        operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
+        let refinedBaseURL = (baseURL.absoluteString.hasSuffix("/") ? baseURL : baseURL.appendingPathComponent(""))
+        super.init(baseURL: refinedBaseURL.absoluteURL, credential: credential, cache: cache)
    }
    
-    deinit {
-        if fileProviderCancelTasksOnInvalidating {
-            _session?.invalidateAndCancel()
-        } else {
-            _session?.finishTasksAndInvalidate()
+    public required convenience init?(coder aDecoder: NSCoder) {
+        guard let baseURL = aDecoder.decodeObject(forKey: "baseURL") as? URL else {
+            return nil
        }
+        self.init(baseURL: baseURL,
+                  credential: aDecoder.decodeObject(forKey: "credential") as? URLCredential)
+        self.useCache        = aDecoder.decodeBool(forKey: "useCache")
+        self.validatingCache = aDecoder.decodeBool(forKey: "validatingCache")
    }
    
-    open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
-        let opType = FileOperationType.fetch(path: path)
-        let url = self.url(of: path).appendingPathComponent("")
-        var request = URLRequest(url: url)
-        request.httpMethod = "PROPFIND"
-        request.setValue("1", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
-        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
-        runDataTask(with: request, operationHandle: RemoteOperationHandle(operationType: opType, tasks: []), completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
-            }
-            var fileObjects = [WebDavFileObject]()
-            if let data = data {
-                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
-                for attr in xresponse where attr.href != url {
-                    if attr.href.path == url.path {
-                        continue
-                    }
-                    fileObjects.append(WebDavFileObject(attr))
-                }
-            }
-            completionHandler(fileObjects, responseError ?? error)
-        })
+    override open func copy(with zone: NSZone? = nil) -> Any {
+        let copy = WebDAVFileProvider(baseURL: self.baseURL!, credential: self.credential, cache: self.cache)!
+        copy.delegate = self.delegate
+        copy.fileOperationDelegate = self.fileOperationDelegate
+        copy.useCache = self.useCache
+        copy.validatingCache = self.validatingCache
+        return copy
    }
    
-    open func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void)) {
+    override open func contentsOfDirectory(path: String, completionHandler: @escaping (([FileObject], Error?) -> Void)) {
+        let query = NSPredicate(format: "TRUEPREDICATE")
+        _ = searchFiles(path: path, recursive: false, query: query, including: [], foundItemHandler: nil, completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameter path: path to target directory. If empty, root will be iterated.
+     - Parameter including: An array which determines which file properties should be considered to fetch.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+     - Parameter contents: An array of `FileObject` identifying the the directory entries.
+     - Parameter error: Error returned by system.
+     */
+    open func contentsOfDirectory(path: String, including: [URLResourceKey], completionHandler: @escaping (_ contents: [FileObject], _ error: Error?) -> Void) {
+        let query = NSPredicate(format: "TRUEPREDICATE")
+        _ = searchFiles(path: path, recursive: false, query: query, including: including, foundItemHandler: nil, completionHandler: completionHandler)
+    }
+    
+    override open func attributesOfItem(path: String, completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
+        self.attributesOfItem(path: path, including: [], completionHandler: completionHandler)
+    }
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameter path: path to target directory. If empty, attributes of root will be returned.
+     - Parameter including: An array which determines which file properties should be considered to fetch.
+     - Parameter completionHandler: a closure with result of directory entries or error.
+     - Parameter attributes: A `FileObject` containing the attributes of the item.
+     - Parameter error: Error returned by system.
+     */
+    open func attributesOfItem(path: String, including: [URLResourceKey], completionHandler: @escaping (_ attributes: FileObject?, _ error: Error?) -> Void) {
        let url = self.url(of: path)
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
-        request.setValue("1", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
-        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
+        request.setValue("0", forHTTPHeaderField: "Depth")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(httpContentType: .xml, charset: .utf8)
+        request.httpBody = WebDavFileObject.xmlProp(including)
        runDataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
+            var responseError: FileProviderHTTPError?
            if let code = (response as? HTTPURLResponse)?.statusCode, code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+                responseError = self.serverError(with: rCode, path: path, data: data)
            }
            if let data = data {
                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
@@ -135,7 +122,7 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        })
    }
    
-    open func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void)) {
+    override open func storageProperties(completionHandler: @escaping (_ volumeInfo: VolumeObject?) -> Void) {
        // Not all WebDAV clients implements RFC2518 which allows geting storage quota.
        // In this case you won't get error. totalSize is NSURLSessionTransferSizeUnknown
        // and used space is zero.
@@ -145,306 +132,197 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
        var request = URLRequest(url: baseURL)
        request.httpMethod = "PROPFIND"
        request.setValue("0", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:prop><D:quota-available-bytes/><D:quota-used-bytes/></D:prop>\n</D:propfind>".data(using: .utf8)
-        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(httpContentType: .xml, charset: .utf8)
+        request.httpBody = WebDavFileObject.xmlProp([.volumeTotalCapacityKey, .volumeAvailableCapacityKey, .creationDateKey])
        runDataTask(with: request, completionHandler: { (data, response, error) in
-            var totalSize: Int64 = -1
-            var usedSize: Int64 = 0
-            if let data = data {
-                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
-                if let attr = xresponse.first {
-                    totalSize = Int64(attr.prop["quota-available-bytes"] ?? "") ?? -1
-                    usedSize = Int64(attr.prop["quota-used-bytes"] ?? "") ?? 0
-                }
+            guard let data = data, let attr = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL).first else {
+                completionHandler(nil)
+                return
            }
-            completionHandler(totalSize, usedSize)
+            
+            let volume = VolumeObject(allValues: [:])
+            volume.creationDate = attr.prop["creationdate"].flatMap { Date(rfcString: $0) }
+            volume.availableCapacity = attr.prop["quota-available-bytes"].flatMap({ Int64($0) }) ?? 0
+            if let usage = attr.prop["quota-used-bytes"].flatMap({ Int64($0) }) {
+                volume.totalCapacity = volume.availableCapacity + usage
+            }
+            completionHandler(volume)
        })
    }
    
-    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
+    open override func searchFiles(path: String, recursive: Bool, query: NSPredicate, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ([FileObject], Error?) -> Void) -> Progress? {
+        return searchFiles(path: path, recursive: recursive, query: query, including: [], foundItemHandler: foundItemHandler, completionHandler: completionHandler)
+    }
+    
+    /**
+     Search files inside directory using query asynchronously.
+     
+     - Note: Query string is limited to file name, to search based on other file attributes, use NSPredicate version.
+     
+     - Parameters:
+       - path: location of directory to start search
+       - recursive: Searching subdirectories of path
+       - query: Simple string that file name begins with to be search, case-insensitive.
+       - including: An array which determines which file properties should be considered to fetch.
+       - foundItemHandler: Closure which is called when a file is found
+       - completionHandler: Closure which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+       - files: all files meat the `query` criteria.
+       - error: `Error` returned by server if occured.
+     */
+    open func searchFiles(path: String, recursive: Bool, query: NSPredicate, including: [URLResourceKey], foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping (_ files: [FileObject], _ error: Error?) -> Void) -> Progress? {
        let url = self.url(of: path)
        var request = URLRequest(url: url)
        request.httpMethod = "PROPFIND"
-        //request.setValue("1", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:allprop/></D:propfind>".data(using: .utf8)
-        runDataTask(with: request, completionHandler: { (data, response, error) in
+        // Depth infinity is disabled on some servers. Implement workaround?!
+        request.setValue(recursive ? "infinity" : "1", forHTTPHeaderField: "Depth")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(httpContentType: .xml, charset: .utf8)
+        request.httpBody = WebDavFileObject.xmlProp([])
+        let progress = Progress(totalUnitCount: -1)
+        progress.setUserInfoObject(url, forKey: .fileURLKey)
+        
+        let queryIsTruePredicate = query.predicateFormat == "TRUEPREDICATE"
+        let task = session.dataTask(with: request) { (data, response, error) in
            // FIXME: paginating results
-            var responseError: FileProviderWebDavError?
+            var responseError: FileProviderHTTPError?
            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+                responseError = self.serverError(with: rCode, path: path, data: data)
            }
-            if let data = data {
-                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
-                var fileObjects = [WebDavFileObject]()
-                for attr in xresponse {
-                    let fileObject = WebDavFileObject(attr)
-                    if !query.evaluate(with: fileObject.mapPredicate()) {
-                        continue
-                    }
-                    
-                    fileObjects.append(fileObject)
-                    foundItemHandler?(fileObject)
-                }
-                completionHandler(fileObjects, responseError ?? error)
+            guard let data = data else {
+                completionHandler([], responseError ?? error)
                return
            }
-            completionHandler([], responseError ?? error)
-        })
+            
+            let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+            var fileObjects = [WebDavFileObject]()
+            for attr in xresponse where attr.href.path != url.path {
+                let fileObject = WebDavFileObject(attr)
+                if !queryIsTruePredicate && !query.evaluate(with: fileObject.mapPredicate()) {
+                    continue
+                }
+                
+                fileObjects.append(fileObject)
+                progress.completedUnitCount = Int64(fileObjects.count)
+                foundItemHandler?(fileObject)
+            }
+            completionHandler(fileObjects, responseError ?? error)
+        }
+        progress.cancellationHandler = { [weak task] in
+            task?.cancel()
+        }
+        progress.setUserInfoObject(Date(), forKey: .startingTimeKey)
+        task.resume()
+        return progress
    }
    
-    open func isReachable(completionHandler: @escaping (Bool) -> Void) {
+    override open func isReachable(completionHandler: @escaping (Bool) -> Void) {
        var request = URLRequest(url: baseURL!)
        request.httpMethod = "PROPFIND"
        request.setValue("0", forHTTPHeaderField: "Depth")
-        request.setValue("text/xml; charset=\"utf-8\"", forHTTPHeaderField: "Content-Type")
-        request.httpBody = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n<D:prop><D:quota-available-bytes/><D:quota-used-bytes/></D:prop>\n</D:propfind>".data(using: .utf8)
-        request.setValue(String(request.httpBody!.count), forHTTPHeaderField: "Content-Length")
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(httpContentType: .xml, charset: .utf8)
+        request.httpBody = WebDavFileObject.xmlProp([.volumeTotalCapacityKey, .volumeAvailableCapacityKey])
        runDataTask(with: request, completionHandler: { (data, response, error) in
            let status = (response as? HTTPURLResponse)?.statusCode ?? 400
            completionHandler(status < 300)
        })
    }
    
-    open weak var fileOperationDelegate: FileOperationDelegate?
-}
-
-extension WebDAVFileProvider: FileProviderOperations {
-    @discardableResult
-    open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = self.url(of: atPath).appendingPathComponent(folderName, isDirectory: true)
-        var request = URLRequest(url: url)
-        request.httpMethod = "MKCOL"
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: url.relativePath, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+    open func publicLink(to path: String, completionHandler: @escaping ((URL?, FileObject?, Date?, Error?) -> Void)) {
+        guard self.baseURL?.host?.contains("dav.yandex.") ?? false else {
+            dispatch_queue.async {
+                completionHandler(nil, nil, nil, self.urlError(path, code: .resourceUnavailable))
            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
-    @discardableResult
-    open func create(file fileName: String, at path: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.create(path: (path as NSString).appendingPathComponent(fileName))
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = self.url(of: path).appendingPathComponent(fileName)
-        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
-            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
-    @discardableResult
-    open func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.move(source: path, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, overwrite: overwrite, completionHandler: completionHandler)
-    }
-    
-    @discardableResult
-    open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.remove(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        return self.doOperation(operation: opType, completionHandler: completionHandler)
-    }
-    
-    func doOperation(operation opType: FileOperationType, overwrite: Bool? = nil, completionHandler: SimpleCompletionHandler) -> OperationHandle?  {
-        let source = opType.source!
-        let sourceURL = self.url(of: source)
-        var request = URLRequest(url: sourceURL)
-        if let dest = opType.destination {
-            request.setValue(url(of:dest).absoluteString, forHTTPHeaderField: "Destination")
-        }
-        switch opType {
-        case .copy:
-            request.httpMethod = "COPY"
-        case .move:
-            request.httpMethod = "MOVE"
-        case .remove:
-            request.httpMethod = "DELETE"
-        default:
-            return nil
+            return
        }
        
-        if let overwrite = overwrite, !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
-        }
-        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let response = response as? HTTPURLResponse, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                if response.statusCode >= 300  {
-                    responseError = FileProviderWebDavError(code: code, path: source, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: sourceURL)
-                }
-                if code == .multiStatus, let data = data {
-                    let xresponses = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
-                    for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
-                        let error = FileProviderWebDavError(code: code, path: source, errorDescription: String(data: data, encoding: .utf8), url: sourceURL)
-                        completionHandler?(error)
-                    }
-                }
-            }
-            if (response as? HTTPURLResponse)?.statusCode ?? 0 != FileProviderHTTPErrorCode.multiStatus.rawValue {
-                completionHandler?(responseError ?? error)
-            }
-            
-            self.delegateNotify(opType, error: responseError ?? error)
-        })
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
-    @discardableResult
-    open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = self.url(of:toPath)
+        let url = self.url(of: path)
        var request = URLRequest(url: url)
-        if !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
-        }
-        request.httpMethod = "PUT"
-        let task = session.uploadTask(with: request, fromFile: localFile, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
+        request.httpMethod = "PROPPATCH"
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.set(httpContentType: .xml, charset: .utf8)
+        let body = "<propertyupdate xmlns=\"DAV:\">\n<set><prop>\n<public_url xmlns=\"urn:yandex:disk:meta\">true</public_url>\n</prop></set>\n</propertyupdate>"
+        request.httpBody = body.data(using: .utf8)
+        runDataTask(with: request, completionHandler: { (data, response, error) in
+            var responseError: FileProviderHTTPError?
+            if let code = (response as? HTTPURLResponse)?.statusCode, code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                responseError = self.serverError(with: rCode, path: path, data: data)
            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        }) 
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-    
-    @discardableResult
-    open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
-        }
-        let url = self.url(of:path)
-        let request = URLRequest(url: url)
-        let task = session.downloadTask(with: request, completionHandler: { (sourceFileURL, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: nil, url: url)
-            }
-            if let sourceFileURL = sourceFileURL {
-                do {
-                    try FileManager.default.copyItem(at: sourceFileURL, to: toLocalURL)
-                } catch let e {
-                    completionHandler?(e)
+            if let data = data {
+                let xresponse = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+                if let urlStr = xresponse.first?.prop["public_url"], let url = URL(string: urlStr) {
+                    completionHandler(url, nil, nil, nil)
                    return
                }
            }
-            completionHandler?(responseError ?? error)
-            self.delegateNotify(opType, error: responseError ?? error)
-        }) 
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
-    }
-}
-
-extension WebDAVFileProvider: FileProviderReadWrite {
-    @discardableResult
-    open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 || offset < 0 {
-            dispatch_queue.async {
-                completionHandler(Data(), nil)
-            }
-            return nil
-        }
-        
-        let opType = FileOperationType.fetch(path: path)
-        let url = self.url(of: path)
-        var request = URLRequest(url: url)
-        request.httpMethod = "GET"
-        if length > 0 {
-            request.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else if offset > 0 && length < 0 {
-            request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
-        }
-        let handle = RemoteOperationHandle(operationType: opType, tasks: [])
-        runDataTask(with: request, operationHandle: handle, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: url)
-            }
-            completionHandler(data, responseError ?? error)
+            completionHandler(nil, nil, nil, responseError ?? error)
        })
-        return handle
    }
    
-    @discardableResult
-    open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.modify(path: path)
-        guard fileOperationDelegate?.fileProvider(self, shouldDoOperation: opType) ?? true == true else {
-            return nil
+    override func request(for operation: FileOperationType, overwrite: Bool = true, attributes: [URLResourceKey: Any] = [:]) -> URLRequest {
+        let method: String
+        let url: URL
+        let sourceURL = self.url(of: operation.source)
+        
+        switch operation {
+        case .fetch:
+            method = "GET"
+            url = sourceURL
+        case .create:
+            if sourceURL.absoluteString.hasSuffix("/") {
+                method = "MKCOL"
+                url = sourceURL
+            } else {
+                fallthrough
+            }
+        case .modify:
+            method = "PUT"
+            url = sourceURL
+            break
+        case .copy(let source, let dest):
+            if source.hasPrefix("file://") {
+                method = "PUT"
+                url = self.url(of: dest)
+            } else if dest.hasPrefix("file://") {
+                method = "GET"
+                url = sourceURL
+            } else {
+                method = "COPY"
+                url = sourceURL
+            }
+        case .move:
+            method = "MOVE"
+            url = sourceURL
+        case .remove:
+            method = "DELETE"
+            url = sourceURL
+        default:
+            fatalError("Unimplemented operation \(operation.description) in \(#file)")
        }
-        // FIXME: lock destination before writing process
-        let url = atomically ? self.url(of: path).appendingPathExtension("tmp") : self.url(of: path)
+        
        var request = URLRequest(url: url)
-        request.httpMethod = "PUT"
-        if !overwrite {
-            request.setValue("F", forHTTPHeaderField: "Overwrite")
+        request.httpMethod = method
+        request.set(httpAuthentication: credential, with: credentialType)
+        request.setValue(overwrite ? "T" : "F", forHTTPHeaderField: "Overwrite")
+        if let dest = operation.destination, !dest.hasPrefix("file://") {
+            request.setValue(self.url(of:dest).absoluteString, forHTTPHeaderField: "Destination")
+        }
+        
+        return request
+    }
+    
+    override func serverError(with code: FileProviderHTTPErrorCode, path: String?, data: Data?) -> FileProviderHTTPError {
+        return FileProviderWebDavError(code: code, path: path ?? "", errorDescription:  data.flatMap({ String(data: $0, encoding: .utf8) }), url: self.url(of: path ?? ""))
+    }
+    
+    override func multiStatusHandler(source: String, data: Data, completionHandler: SimpleCompletionHandler) {
+        let xresponses = DavResponse.parse(xmlResponse: data, baseURL: self.baseURL)
+        for xresponse in xresponses where (xresponse.status ?? 0) >= 300 {
+            let code = xresponse.status.flatMap { FileProviderHTTPErrorCode(rawValue: $0) } ?? .internalServerError
+            let error = self.serverError(with: code, path: source, data: data)
+            completionHandler?(error)
        }
-        let task = session.uploadTask(with: request, from: data, completionHandler: { (data, response, error) in
-            var responseError: FileProviderWebDavError?
-            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
-                responseError = FileProviderWebDavError(code: rCode, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8), url: self.url(of: path))
-            }
-            defer {
-                self.delegateNotify(opType, error: responseError ?? error)
-            }
-            if let error = error {
-                completionHandler?(error)
-                return
-            }
-            if atomically {
-                self.moveItem(path: (path as NSString).appendingPathExtension("tmp")!, to: path, completionHandler: completionHandler)
-            }
-        }) 
-        task.taskDescription = opType.json
-        task.resume()
-        return RemoteOperationHandle(operationType: opType, tasks: [task])
    }
    
    /*
@@ -463,32 +341,54 @@ extension WebDAVFileProvider: FileProviderReadWrite {
    // TODO: implements methods for lock mechanism
 }

-extension WebDAVFileProvider: FileProvider {
-    open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = WebDAVFileProvider(baseURL: self.baseURL!, credential: self.credential, cache: self.cache)!
-        copy.currentPath = self.currentPath
-        copy.delegate = self.delegate
-        copy.fileOperationDelegate = self.fileOperationDelegate
-        copy.useCache = self.useCache
-        copy.validatingCache = self.validatingCache
-        return copy
+extension WebDAVFileProvider: ExtendedFileProvider {
+    open func thumbnailOfFileSupported(path: String) -> Bool {
+        guard self.baseURL?.host?.contains("dav.yandex.") ?? false else {
+            return false
+        }
+        let supportedExt: [String] = ["jpg", "jpeg", "png", "gif"]
+        return supportedExt.contains((path as NSString).pathExtension)
+    }
+    
+    open func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((ImageClass?, Error?) -> Void)) {
+        guard self.baseURL?.host?.contains("dav.yandex.") ?? false else {
+            dispatch_queue.async {
+                completionHandler(nil, self.urlError(path, code: .resourceUnavailable))
+            }
+            return
+        }
+        
+        let dimension = dimension ?? CGSize(width: 64, height: 64)
+        let url = URL(string: self.url(of: path).absoluteString + "?preview&size=\(dimension.width)x\(dimension.height)")!
+        var request = URLRequest(url: url)
+        request.httpMethod = "GET"
+        request.set(httpAuthentication: credential, with: credentialType)
+        let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
+            var responseError: FileProviderHTTPError?
+            if let code = (response as? HTTPURLResponse)?.statusCode , code >= 300, let rCode = FileProviderHTTPErrorCode(rawValue: code) {
+                responseError = self.serverError(with: rCode, path: url.relativePath, data: data)
+                completionHandler(nil, responseError ?? error)
+                return
+            }
+            
+            completionHandler(data.flatMap({ ImageClass(data: $0) }), nil)
+        })
+        task.resume()
+    }
+    
+    open func propertiesOfFileSupported(path: String) -> Bool {
+        return false
+    }
+    
+    open func propertiesOfFile(path: String, completionHandler: @escaping (([String : Any], [String], Error?) -> Void)) {
+        dispatch_queue.async {
+            completionHandler([:], [], self.urlError(path, code: .resourceUnavailable))
+        }
    }
 }

 // MARK: WEBDAV XML response implementation

-internal extension WebDAVFileProvider {
-    fileprivate func delegateNotify(_ operation: FileOperationType, error: Error?) {
-        DispatchQueue.main.async(execute: {
-            if error == nil {
-                self.delegate?.fileproviderSucceed(self, operation: operation)
-            } else {
-                self.delegate?.fileproviderFailed(self, operation: operation)
-            }
-        })
-    }
-}
-
 struct DavResponse {
    let href: URL
    let hrefString: String
@@ -497,12 +397,13 @@ struct DavResponse {
    
    init? (_ node: AEXMLElement, baseURL: URL?) {
        
-        func removeSlash(_ str: String) -> String {
-            if str.hasPrefix("/") {
-                return str.substring(from: str.index(after: str.startIndex))
-            } else {
-                return str
-            }
+        func standardizePath(_ str: String) -> String {
+            #if swift(>=4.0)
+            let trimmedStr = str.hasPrefix("/") ? String(str[str.index(after: str.startIndex)...]) : str
+            #else
+            let trimmedStr = str.hasPrefix("/") ? str.substring(from: str.index(after: str.startIndex)) : str
+            #endif
+            return trimmedStr.addingPercentEncoding(withAllowedCharacters: .filePathAllowed) ?? str
        }
        
        // find node names with namespace
@@ -524,9 +425,14 @@ struct DavResponse {
        guard let hrefString = node[hreftag].value else { return nil }
        
        // trying to figure out relative path out of href
-        let hrefAbsolute = URL(string: hrefString, relativeTo: baseURL)?.absoluteString ?? hrefString
-        let relativePath = hrefAbsolute.replacingOccurrences(of: baseURL?.absoluteString ?? "", with: "", options: .anchored, range: nil)
-        let hrefURL = URL(string: removeSlash(relativePath), relativeTo: baseURL) ?? baseURL
+        let hrefAbsolute = URL(string: hrefString, relativeTo: baseURL)?.absoluteURL
+        let relativePath: String
+        if hrefAbsolute?.host?.replacingOccurrences(of: "www.", with: "", options: .anchored) == baseURL?.host?.replacingOccurrences(of: "www.", with: "", options: .anchored) {
+            relativePath = hrefAbsolute?.path.replacingOccurrences(of: baseURL?.absoluteURL.path ?? "", with: "", options: .anchored, range: nil) ?? hrefString
+        } else {
+            relativePath = hrefAbsolute?.absoluteString.replacingOccurrences(of: baseURL?.absoluteString ?? "", with: "", options: .anchored, range: nil) ?? hrefString
+        }
+        let hrefURL = URL(string: standardizePath(relativePath), relativeTo: baseURL) ?? baseURL
        
        guard let href = hrefURL?.standardized else { return nil }
        
@@ -588,14 +494,14 @@ struct DavResponse {
 public final class WebDavFileObject: FileObject {
    internal init(_ davResponse: DavResponse) {
        let href = davResponse.href
-        let name = davResponse.prop["displayname"] ?? (davResponse.hrefString.removingPercentEncoding! as NSString).lastPathComponent
+        let name = davResponse.prop["displayname"] ?? davResponse.href.lastPathComponent
        let relativePath = href.relativePath
        let path = relativePath.hasPrefix("/") ? relativePath : ("/" + relativePath)
        super.init(url: href, name: name, path: path)
        self.size = Int64(davResponse.prop["getcontentlength"] ?? "-1") ?? NSURLSessionTransferSizeUnknown
-        self.creationDate = resolve(dateString: davResponse.prop["creationdate"] ?? "")
-        self.modifiedDate = resolve(dateString: davResponse.prop["getlastmodified"] ?? "")
-        self.contentType = davResponse.prop["getcontenttype"] ?? "octet/stream"
+        self.creationDate = davResponse.prop["creationdate"].flatMap { Date(rfcString: $0) }
+        self.modifiedDate = davResponse.prop["getlastmodified"].flatMap { Date(rfcString: $0) }
+        self.contentType = davResponse.prop["getcontenttype"] ?? "application/octet-stream"
        self.isHidden = (Int(davResponse.prop["ishidden"] ?? "0") ?? 0) > 0
        self.type = self.contentType == "httpd/unix-directory" ? .directory : .regular
        self.entryTag = davResponse.prop["getetag"]
@@ -604,22 +510,63 @@ public final class WebDavFileObject: FileObject {
    /// MIME type of the file.
    open internal(set) var contentType: String {
        get {
-            return allValues[.mimeType] as? String ?? ""
+            return allValues[.mimeTypeKey] as? String ?? "application/octet-stream"
        }
        set {
-            allValues[.mimeType] = newValue
+            allValues[.mimeTypeKey] = newValue
        }
    }
    
    /// HTTP E-Tag, can be used to mark changed files.
    open internal(set) var entryTag: String? {
        get {
-            return allValues[.entryTag] as? String
+            return allValues[.entryTagKey] as? String
        }
        set {
-            allValues[.entryTag] = newValue
+            allValues[.entryTagKey] = newValue
        }
    }
+    
+    internal class func resourceKeyToDAVProp(_ key: URLResourceKey) -> String? {
+        switch key {
+        case URLResourceKey.fileSizeKey:
+            return "getcontentlength"
+        case URLResourceKey.creationDateKey:
+            return "creationdate"
+        case URLResourceKey.contentModificationDateKey:
+            return "getlastmodified"
+        case URLResourceKey.fileResourceTypeKey, URLResourceKey.mimeTypeKey:
+            return "getcontenttype"
+        case URLResourceKey.isHiddenKey:
+            return "ishidden"
+        case URLResourceKey.entryTagKey:
+            return "getetag"
+        case URLResourceKey.volumeTotalCapacityKey:
+            // WebDAV doesn't have total capacity, but it's can be calculated via used capacity
+            return "quota-used-bytes"
+        case URLResourceKey.volumeAvailableCapacityKey:
+            return "quota-available-bytes"
+        default:
+            return nil
+        }
+    }
+    
+    internal class func propString(_ keys: [URLResourceKey]) -> String {
+        var propKeys = ""
+        for item in keys {
+            if let prop = WebDavFileObject.resourceKeyToDAVProp(item) {
+                propKeys += "<D:prop><D:\(prop)/></D:prop>"
+            }
+        }
+        if propKeys.isEmpty {
+            propKeys = "<D:allprop/>"
+        }
+        return propKeys
+    }
+    
+    internal class func xmlProp(_ keys: [URLResourceKey]) -> Data {
+        return "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n<D:propfind xmlns:D=\"DAV:\">\n\(WebDavFileObject.propString(keys))\n</D:propfind>".data(using: .utf8)!
+    }
 }

 /// Error returned by WebDAV server when trying to access or do operations on a file or folder.
Author	SHA1	Message	Date
Amir Abbas	435ed37d93	Updated pod version to 0.21	2017-10-27 09:21:17 +03:30
Amir Abbas	9e4a803345	Removed unnecessary properties from SessionDelegate	2017-10-26 14:07:57 +03:30
Amir Abbas	0e53036855	Added progressive downloading for HTTP-based providers - Added HEIC/HEIF image thumbnail and properties - Fixed bug: data task recieve data body called only once	2017-10-26 13:56:41 +03:30
Amir Abbas	87317c1d42	Fixed #61 , OneDrive progress availibility	2017-10-13 08:55:55 +03:30
Amir Abbas	4c35e446a7	Fix provider base url (as directory), caused Cloud provider misbehaves	2017-10-13 02:31:31 +03:30
Amir Abbas	47516c63ad	Refactored contentsOfDirectory to searchFiles where applicable	2017-10-12 18:30:28 +03:30
Amir Abbas	6cd5b7d8c5	Fixed error description in Dropbox (except uploads) - Refactors in Dropbox request maker method	2017-10-11 01:14:02 +03:30
Amir Abbas	598444c90f	Codebeat GPA improvements	2017-10-10 16:48:55 +03:30
Amir Abbas	370866442a	Fixed Compilation error for upload size type	2017-10-10 11:40:32 +03:30
Amir Abbas	9cc9a6a96a	Improving documentation - Renaming OneDriveProvider.SubAddress to Route - Refactors to improve codebeat score	2017-10-10 11:07:28 +03:30
Amir Abbas	2969af28b8	Small refactors	2017-10-09 13:32:46 +03:30
Amir Abbas	d41e86b30a	Fixed Swift 3 flatMap error	2017-10-09 11:31:02 +03:30
Amir Abbas	aaa1def9e7	Refactored paginated listing in Dropbox and OneDrive - Removed currentPath	2017-10-09 11:16:17 +03:30
Amir Abbas	024a3637b4	Fix compile time error	2017-10-04 16:32:54 +03:30
Amir Abbas	b20fc3efe5	Fix compilation error on swift 3	2017-10-04 15:11:26 +03:30
Amir Abbas	682dd40072	File coordination enabled by default for copyItem(locaURL:) methods	2017-10-04 15:06:27 +03:30
Amir Abbas	3f35e600cd	Removing deprecated String.characters usage - Documentation for using file id in Dropbox & OneDrive	2017-10-04 15:04:23 +03:30
Amir Abbas	9cd2fa2e3a	Compilation optimizations, refactoring	2017-10-01 02:04:29 +03:30
Amir Abbas	7be6985454	Updated OneDrive API to new version	2017-09-29 21:39:28 +03:30
Amir Abbas	04ac3e22e7	Refactored correctPath to specified providers	2017-09-29 20:51:09 +03:30
Amir Abbas	c8de7fdb69	Fixed NSProgress parenting, iCloud KVO, crash in url(of)	2017-09-29 18:11:26 +03:30
Amir Abbas	42b879d4e2	Fix Swift 3 bug	2017-09-24 15:37:00 +03:30
Amir Abbas	5800c9a2ec	Improved compile speed, Fixed Swift 4 warnings	2017-09-24 13:12:31 +03:30
Amir Abbas Mousavian	7c9b2bf09a	Merge pull request #65 from yuyan7/fix_webdav Fix HTTP providers not be overwritten	2017-09-16 20:31:59 +04:30
yuya-nakamura	ba08cdda1d	Fixed WebDAV not be overwritten	2017-09-16 23:01:57 +09:00
Amir Abbas	b380685932	Added VolumeObject for storageProperties method - Refined error handling in HTTP provider - Added contentType and hash to OneDriveFileObject	2017-09-05 02:26:09 +04:30
Amir Abbas	5a5beb6891	Refined error handling	2017-09-04 01:22:44 +04:30
Amir Abbas	c7201a8be7	Fixed currentPath docs, delegateNotify method default error arg	2017-08-29 01:40:15 +04:30
Amir Abbas	d2a03369fd	Fixed FTP crash on rucursive remove	2017-08-28 00:06:02 +04:30
Amir Abbas	d08098008a	Removed FoundationErrorEnum, Refactoed delegate progress routine	2017-08-27 13:48:29 +04:30
Amir Abbas	3c5303214e	Fixed Array extension error in HashMAC	2017-08-24 15:08:22 +04:30
Amir Abbas	ad8f333d16	Fixed swift 3 compile error on Array extenson	2017-08-24 08:36:11 +04:30
Amir Abbas	5e8f653c52	Fixed compile bug in Swift 3.0 for Array.Iterator.Element	2017-08-23 23:21:17 +04:30
Amir Abbas	e4cd7ddf22	Fixed Quality<T> percision	2017-08-23 22:18:18 +04:30
Amir Abbas	1efb0e3fe5	Fixed Quality<T>	2017-08-23 22:15:45 +04:30
Amir Abbas	1292856646	Added convenience methods for URLRequest headers	2017-08-23 22:04:47 +04:30
Amir Abbas	e39f9c29ec	Merge commit '3d44de0b407c3cd604189cc161dc1fc039409763'	2017-08-23 10:54:59 +04:30
Amir Abbas	f43199c22a	fixed colon in url string problem across provider	2017-08-23 10:52:45 +04:30
Amir Abbas Mousavian	3d44de0b40	Added missed filePathAllowed const to CharacterSet	2017-08-23 01:22:19 +04:30
Amir Abbas	21b5214481	Deprecate currentPath property, returning error in provider delegate - Using checkResourceIsReachable to check file exists - fixed bug: downloading/uploading files with colon in name	2017-08-23 01:19:56 +04:30
Amir Abbas	f0b4925db2	Consistancy to delegate call in all contents(of:) methods - renamed opType instances to operation - moved to v2 in Dropbox - removed redundant CloudFileProvider methods	2017-08-20 22:41:53 +04:30
Amir Abbas	0da957d25f	Making protocol method implementations overridable	2017-08-19 19:47:54 +04:30
Amir Abbas	0de558c160	Recursive search fixed in FTP, OneDrive, WebDAV	2017-08-19 06:49:15 +04:30
Amir Abbas	cad68da076	Refactored Dropbox, WebDAV & OneDrive to HTTPFileProvider - FileOperationType.source is not optional anymore - critical bugfix: KVO exception crash on task completion	2017-08-19 05:51:25 +04:30
Amir Abbas Mousavian	39da09edd4	Merge pull request #60 from evilutioner/master Fixed file downloading progress	2017-08-15 18:53:21 +04:30
Amir Abbas	5129aee1b5	Added fileURL to Progress	2017-08-15 18:41:48 +04:30
Oleg Marchik	478f0819b5	Fixed file downloading progress	2017-08-15 16:57:50 +03:00
Amir Abbas	b2a7800f7c	Fixed typo	2017-08-15 15:08:06 +04:30
Amir Abbas	96c102d156	Updated readme and podspec to ver 0.19.0	2017-08-15 14:57:36 +04:30
Amir Abbas	8aedd8e72a	Replaced OperationHandle with (NS)Progress	2017-08-15 13:42:41 +04:30
Amir Abbas	5b55debe8a	Fix warning in OneDrive provider	2017-08-12 17:50:00 +04:30
Amir Abbas Mousavian	0fa062a946	Merge pull request #59 from evilutioner/master OneDrive: list folder issue fixed, removed escape symbols in path	2017-08-11 20:43:28 +04:30
Oleg Marchik	879f86c1f9	Merge branch 'master' into master	2017-08-11 18:07:25 +03:00
Oleg Marchik	80d5f02bbd	OneDrive: list folder issue fixed, removed escape symbols in path	2017-08-11 18:04:18 +03:00
Amir Abbas Mousavian	b8a7721b2f	Merge pull request #58 from evilutioner/master Dropbox bug fixing: added unicode symbols support in http header path	2017-08-10 22:29:08 +04:30
Oleg Marchik	44b4784cd3	Important dropbox bug fixing: added unicode symbols support in path	2017-08-10 11:36:15 +03:00
Amir Abbas	7d9e2247f2	Fixed Compile error, removed redundant comments	2017-08-04 00:30:46 +04:30
Amir Abbas Mousavian	0ace562442	Merge pull request #57 from evilutioner/master Fixed outdated OneDrive API	2017-08-04 00:27:36 +04:30
evilutioner	63d831ef90	Merge branch 'master' into master	2017-08-01 16:08:51 +03:00
Oleg Marchik	d6b91348a3	Fixed outdated OneDrive API	2017-08-01 12:55:39 +03:00
Amir Abbas	fd9d4c1ab4	Probable fix for # 55 (OneDrive url issue)	2017-07-31 20:10:40 +04:30
Amir Abbas	41e266c2a9	Fix #54(FTP login), Refactored ExtendedLocalFileProvider	2017-07-17 05:36:30 +04:30
Amir Abbas	6127f4a7d9	Fixed Readme errors	2017-07-14 19:28:41 +04:30
Amir Abbas	faca943beb	Updated Readme fot FTP and SMB description	2017-07-14 16:49:55 +04:30
Amir Abbas	9345436fa2	Enhanced PDF Meta-info, Better FTPS handling	2017-07-14 16:49:24 +04:30
Amir Abbas	6228d88d41	Adjusting readme badges	2017-07-05 21:35:15 +04:30
Amir Abbas	5b395915a9	Updated Readme for Pods and SPM file	2017-07-02 18:26:34 +04:30
Amir Abbas	e4f12a502b	Fixed repo name and Readme	2017-07-01 16:57:23 +04:30
Amir Abbas	8faad0ec65	Fixed project name in schemes	2017-07-01 14:14:45 +04:30
Amir Abbas	bd5569d213	Updated scheme names	2017-07-01 14:09:39 +04:30
Amir Abbas	14ed279879	Renamed framework for compatibility with iOS 11	2017-07-01 13:50:22 +04:30
Amir Abbas	fd293f7bdb	[Amend] Fixed swift 3.0 compile error for type(of:)	2017-07-01 11:08:49 +04:30
Amir Abbas	3d9625e243	Fixed swift 3.0 compile error for type(of:)	2017-07-01 11:03:22 +04:30
Amir Abbas	0d017ebfc4	Fix #52 (Swift 4.0 source compatibility)	2017-07-01 10:47:48 +04:30
Amir Abbas	fd36df67f3	FTP passive property encoding - removed redundant protocol conforming	2017-07-01 09:43:45 +04:30
Amir Abbas	5be8c4ef5e	podspec and version update	2017-06-27 14:02:00 +04:30
Amir Abbas	0374fd7688	Making ftp active data task creation async	2017-06-24 12:09:16 +04:30
Amir Abbas	5ddfa43555	Fix #49 (Workaround colon in url path bug in NSURL relative url)	2017-06-24 12:04:50 +04:30
Amir Abbas	21850bb548	Probable fix for #51	2017-06-24 11:44:12 +04:30
Amir Abbas	b166e111e0	FTP Active mode, FTPS bugfix, possible fix for #47	2017-05-25 17:33:56 +04:30
Amir Abbas	1dd7561215	Caching ftp server support for RFC3659, Possible fix for #47	2017-05-23 19:10:04 +04:30
Amir Abbas	f94719deb0	Fixes #39 (FTP listing), Error domain determination	2017-05-05 13:02:07 +04:30
Amir Abbas	b13df0a977	Fixes #38 (Creating folder on WebDAV)	2017-05-05 10:06:17 +04:30
Amir Abbas	24af7aa4c2	Fixed LocalFileProvider init baseURL issue	2017-04-20 01:27:59 +04:30
Amir Abbas	06039ad993	CloudFileProvider operation handle improvements	2017-04-20 01:06:36 +04:30
Amir Abbas Mousavian	d8fec3e346	Merge pull request #37 from hansvdam/master Making `inProgress` of LocalFileProvider working	2017-04-18 14:22:08 +04:30
Hans van Dam	5c93bc8731	making 'inProgress' of LocalFileProvider work more consistently	2017-04-18 11:03:35 +02:00
Hans van Dam	61ba245189	making 'inProgress' of LocalFileProvider work	2017-04-17 18:16:04 +02:00
Amir Abbas	02e6cd37dd	WebDAV OAuth 1,2 support	2017-04-16 19:19:17 +04:30
Amir Abbas	55608fb8d0	New FileProviderSharing protocol for publicLinks - fixed DropboxFileProvider.propertiesOfFile() bug - minor URLRequest refactors - Added documentation and scope declaration	2017-04-16 19:07:45 +04:30
Amir Abbas	3e3582f6fa	Changed DropboxFileProvider.type constant to “Dropbox”	2017-04-15 21:31:47 +04:30
Amir Abbas	dd7a9d20b6	Fixed macOS build error	2017-04-14 23:26:40 +04:30
Amir Abbas	d4a9b4a34f	Fixed Dropbox thumbnail issue	2017-04-14 22:07:35 +04:30
Amir Abbas	34c663e62c	FileObject.url is unwraped. fixed url initializing from path	2017-04-14 18:57:50 +04:30
Amir Abbas	1415dda987	Fixed #36 (FTP Uploading bug)	2017-04-14 18:55:07 +04:30
Amir Abbas	cd465c1288	Fixes #35 (Dropbox handlers), Fixed FTP response reading length	2017-04-14 11:15:09 +04:30
Amir Abbas	a605b0cd85	Added FTP Recursive listing, Implemented ftp search - Implemented FTP full directory remove - Fixed FTP STOR bug - Implemented relativePath(of:) for FTP - Initial implementation of FTP active mode	2017-04-11 22:21:13 +04:30
Amir Abbas	bf7043de29	Fixed `relativePath(of:)` bug, made it overridable - Fixed StreamTask.taskDescription bug	2017-04-11 19:43:34 +04:30
Amir Abbas	ff5e13931f	Fixed WebDAVProvider.contents bug, refactored FTP Error	2017-04-09 14:09:03 +04:30
Amir Abbas	75af738d2e	Made SessionDelegate init public, fixed pod issue	2017-04-05 02:05:28 +04:30
Amir Abbas	f54a1253e4	Throwing error when trying to upload a directory	2017-04-05 00:24:24 +04:30
Amir Abbas	1394a92662	Add Documentation	2017-04-03 21:03:48 +04:30
Amir Abbas	dab171c755	Setting sessionDelgate credential to updated one.	2017-04-03 18:59:50 +04:30
Amir Abbas	ea5de2e2aa	Added progress for content(path:) method - Fixed issue with colliding handlers between sessions. - Sessions can be set. - SessionDelegate class is now public.	2017-04-03 18:50:13 +04:30
Amir Abbas	2253cca086	Fixed deprecated URLResourceKey items	2017-04-03 12:52:27 +04:30
Amir Abbas	e15a900ade	Renamed URLResourceKey additions to have `Key` prefix	2017-04-03 12:49:35 +04:30
Amir Abbas	5c2c56c44c	Fixed: Calling completion handler for upload task - Added including (file object properties) argument to WebDAV provider (resolves #31)	2017-04-03 12:41:11 +04:30
Amir Abbas Mousavian	ff4bbdf0de	Updated readme and podspec for FTP, minor fixes.	2017-04-01 14:56:20 +04:30
Amir Abbas Mousavian	163a218ac2	Fixed operation progress (in delegate) for all remote providers - Now also compatible with background session - added delegate notify (success, progress, failure) to FTP - added `FTPFileProvider.useAppleImplementation`, allows developer choose to use apple download task instead of custom implementation - enabling to download non-text files in FTP - implementation of `url(of:) in FTP - various fixes in error reporting - disabled closing streams in ftpQuit() due to crash	2017-04-01 01:33:56 +04:30
Amir Abbas Mousavian	81401ee36f	Added Documentation, refactors of related Date methods	2017-03-31 10:15:39 +04:30
Amir Abbas Mousavian	759ba3c7bf	Added AEXML license file	2017-03-31 00:49:08 +04:30
Amir Abbas Mousavian	f5c8f6308b	FileProviderStreamTask (URLSessionStreakTask replica) is now public - closing streams after ftpQuit() executed. - added ability to add FTP Active Mode.	2017-03-30 23:49:28 +04:30
Amir Abbas Mousavian	4dbb0adb18	FTP better error handling	2017-03-30 13:16:03 +04:30
Amir Abbas Mousavian	bf62d585fd	implemented FTP copy fallback, FTPS manual auth	2017-03-30 10:41:14 +04:30
Amir Abbas Mousavian	f21f658874	Deprecated create(file:) method, replaced by writeContents() - RemoteOperationHandle now retains task - FTP provider returns correct operation handle task	2017-03-29 23:03:04 +04:30
Amir Abbas	e6eba3d198	Fixed macOS and tvOS build	2017-03-29 10:13:47 +04:30
Amir Abbas	6959a14dc1	Fixed compiler error, closing streams in FTP provider	2017-03-29 09:29:22 +04:30
Amir Abbas	29a9e0fb82	Initial implementation of FTP - ftp copy and search is not implemented	2017-03-29 04:17:03 +04:30
Amir Abbas Mousavian	c7b4e1f124	Ensure baseURL is absolute, fixed warnings for Swift 3.1	2017-03-28 19:25:41 +04:30
Amir Abbas Mousavian	99a433a0fc	Credential is open to set anytime	2017-03-26 15:54:55 +04:30
Amir Abbas Mousavian	4023fbc62e	Fixed: WebDAV file listing omit files contains space in name	2017-03-26 02:03:43 +04:30
Amir Abbas Mousavian	1045901d7c	Added NSCoding support - Better relative path handling in WebDAV - obsolete deprecated methods	2017-03-25 19:19:49 +04:30