Changed FileObject.allValues key type to URLResourceKey

- LocalFileProvider.storageProperties method now uses url resource values

.travis.yml

@@ -3,30 +3,43 @@ language: objective-c
 osx_image: xcode8.2
 
 xcode_project: FileProvider.xcodeproj
+
 env:
   global: 
     - PROJECTNAME="FileProvider"
     - FRAMEWORK_NAME="FileProvider.framework"
-  matrix:
-    - SHCEME="FileProvider OSX" SDK="macosx" ACTION="build"
-    - SHCEME="FileProvider iOS" SDK="iphonesimulator" ACTION="build"
-    - SHCEME="FileProvider tvOS" SDK="appletvsimulator" ACTION="build"
+#  matrix:
+#    - SHCEME="FileProvider OSX" SDK="macosx" ACTION="build"
+#    - SHCEME="FileProvider iOS" SDK="iphonesimulator" ACTION="build"
+#    - SHCEME="FileProvider tvOS" SDK="appletvsimulator" ACTION="build"
+
 before_install:
   - gem install xcpretty --no-rdoc --no-ri --no-document --quiet
   - brew update
   - brew outdated carthage || brew upgrade carthage
+
 script:
   - set pipefail
   - xcodebuild -version
-  - xcodebuild -project $PROJECT.xcodeproj -scheme "$SCHEME" -sdk $SDK $ACTION ONLY_ACTIVE_ARCH=NO | xcpretty
-#  - pod lib lint --quick
+  - pod lib lint --quick
+#  - xcodebuild -project $PROJECTNAME.xcodeproj -scheme "$SCHEME" -sdk $SDK $ACTION ONLY_ACTIVE_ARCH=NO
+  - xcodebuild -project $PROJECTNAME.xcodeproj -scheme "FileProvider OSX" -sdk macosx build | xcpretty
+  - xcodebuild -project $PROJECTNAME.xcodeproj -scheme "FileProvider iOS" -sdk iphonesimulator build ONLY_ACTIVE_ARCH=NO | xcpretty
+  - xcodebuild -project $PROJECTNAME.xcodeproj -scheme "FileProvider tvOS" -sdk appletvsimulator build ONLY_ACTIVE_ARCH=NO | xcpretty
+
 # after_success:
 #   - bash <(curl -s https://codecov.io/bash)
+
 before_deploy:
-  - carthage build --no-skip-current
+  - brew update
+  - brew outdated carthage || brew upgrade carthage
+  - carthage version
   - carthage archive $PROJECTNAME
+  
 deploy:
-  file: $PROJECTNAME.framework.zip
+  provider: releases
+  file: $FRAMEWORK_NAME.zip
   skip_cleanup: true
   on:
+    repo: amosavian/FileProvider
     tags: true

FileProvider.podspec

@@ -16,7 +16,7 @@ Pod::Spec.new do |s|
   #
 
   s.name         = "FileProvider"
-  s.version      = "0.12.0"
+  s.version      = "0.12.3"
   s.summary      = "FileManager replacement for Local and Remote (WebDAV/Dropbox/OneDrive/SMB2) files on iOS and macOS."
 
   # This description is used to generate tags and improve search results.

FileProvider.xcodeproj/project.pbxproj

@@ -603,7 +603,7 @@
 		799396601D48B7BF00086753 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.12.0;
+				BUNDLE_VERSION_STRING = 0.12.3;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -633,7 +633,7 @@
 		799396611D48B7BF00086753 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				BUNDLE_VERSION_STRING = 0.12.0;
+				BUNDLE_VERSION_STRING = 0.12.3;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;

README.md

@@ -12,7 +12,7 @@
 
 [![Build Status][travis-image]][travis-url]
 [![Codebeat Badge][codebeat-image]][codebeat-url]
-[![Cocoapods Docs][docs-image]](docs-url)
+[![Cocoapods Docs][docs-image]][docs-url]
 [![Cocoapods Downloads][cocoapods-downloads]][cocoapods]
 [![Cocoapods Apps][cocoapods-apps]][cocoapods]
 
@@ -29,18 +29,18 @@ Local and WebDAV providers are fully tested and can be used in production enviro
 ## 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] **DropboxFileProvider** A wrapper around Dropbox Web API.
-	* For now it has limitation in uploading files up to 150MB.
-- [x] **OneDriveFileProvider** A wrapper around OneDrive Web API, works with `onedrive.com` and compatible (business) servers.
-* For now it has limitation in uploading files up to 100MB.
-- [x] **CloudFileProvider** A wrapper around app's ubiquitous container to iCloud Drive in iOS 8+ 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 depericated and very tricky to be implemented
+    * 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.
+- [ ] **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.
-- [ ] **AmazonS3FileProvider** 
-- [ ] **GoogleDriveFileProvider**
 
 ## Requirements
 
@@ -69,7 +69,7 @@ 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: 8)
+.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0, minorVersion: 12)
 ```
 
 ### Manually
@@ -141,7 +141,7 @@ let webdavProvider = WebDAVFileProvider(baseURL: URL(string: "http://www.example
 
 * 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)
 
-* 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.
+* 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. Also you can use [auth0/Lock](https://github.com/auth0/Lock.iOS-OSX) which provides graphical user interface.
 	
 For interaction with UI, set delegate variable of `FileProvider` object
 

Sources/AEXML/AEXML.h

@@ -1,29 +0,0 @@
-//
-// AEXML.h
-//
-// Copyright (c) 2014 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.
-//
-
-#import <Foundation/Foundation.h>
-
-FOUNDATION_EXPORT double AEXMLVersionNumber;
-FOUNDATION_EXPORT const unsigned char AEXMLVersionString[];
-

Sources/AEXML/Document.swift

@@ -29,7 +29,7 @@ import Foundation
 
     XML Parsing is also done with this object.
 */
-open class AEXMLDocument: AEXMLElement {
+internal class AEXMLDocument: AEXMLElement {
     
     // MARK: - Properties
     

Sources/AEXML/Element.swift

@@ -30,7 +30,7 @@ import Foundation
     You can access its structure by using subscript like this: `element["foo"]["bar"]` which would
     return `<bar></bar>` element from `<element><foo><bar></bar></foo></element>` XML as an `AEXMLElement` object.
 */
-open class AEXMLElement {
+internal class AEXMLElement {
     
     // MARK: - Properties
     
@@ -86,7 +86,7 @@ open class AEXMLElement {
     /// The first element with given name **(Empty element with error if not exists)**.
     open subscript(key: String) -> AEXMLElement {
         guard let
-            first = children.filter({ $0.name == key }).first
+            first = children.first(where: { $0.name == key })
         else {
             let errorElement = AEXMLElement(name: key)
             errorElement.error = AEXMLError.elementNotFound

Sources/AEXML/Error.swift

@@ -25,7 +25,7 @@
 import Foundation
 
 /// A type representing error value that can be thrown or inside `error` property of `AEXMLElement`.
-public enum AEXMLError: Error {
+internal enum AEXMLError: Error {
     /// This will be inside `error` property of `AEXMLElement` when subscript is used for not-existing element.
     case elementNotFound
     

Sources/AEXML/Info.plist

@@ -1,26 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-<dict>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>en</string>
-	<key>CFBundleExecutable</key>
-	<string>$(EXECUTABLE_NAME)</string>
-	<key>CFBundleIdentifier</key>
-	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleName</key>
-	<string>$(PRODUCT_NAME)</string>
-	<key>CFBundlePackageType</key>
-	<string>FMWK</string>
-	<key>CFBundleShortVersionString</key>
-	<string>3.0.0</string>
-	<key>CFBundleSignature</key>
-	<string>????</string>
-	<key>CFBundleVersion</key>
-	<string>$(CURRENT_PROJECT_VERSION)</string>
-	<key>NSPrincipalClass</key>
-	<string></string>
-</dict>
-</plist>

Sources/AEXML/Options.swift

@@ -9,7 +9,7 @@
 import Foundation
 
 /// Options used in `AEXMLDocument`
-public struct AEXMLOptions {
+internal struct AEXMLOptions {
     
     /// Values used in XML Document header
     public struct DocumentHeader {

Sources/CloudFileProvider.swift

@@ -9,12 +9,10 @@
 import Foundation
 
 open class CloudFileProvider: LocalFileProvider {
+    open override class var type: String { return "iCloudDrive" }
     
-    public var type: String {
-        return "iCloudDrive"
-    }
-    
-    /// Actually is readonly, value is true
+    /// Forces file operations to use `NSFileCoordinating`,
+    /// Actually this is readonly, and value is always true.
     override open var isCoorinating: Bool {
         get {
             return true
@@ -24,9 +22,24 @@ open class CloudFileProvider: LocalFileProvider {
         }
     }
     
-    open var containerId: String?
+    /// The fully-qualified container identifier for an iCloud container directory.
+    open fileprivate(set) var containerId: String?
     
-    public init? (containerId: String?) {
+    /// Scope of container, indicates user can manipulate data/files or not.
+    open fileprivate(set) var scope: UbiquitousScope
+    
+    /**
+     Initializes the provider for the iCloud container associated with the specified identifier and 
+     establishes access to that container.
+     
+     - Important: Do not call this method from your app’s main thread. Because this method might take a nontrivial amount of time to set up iCloud and return the requested URL, you should always call it from a secondary thread.
+     
+     - Parameter containerId: The fully-qualified container identifier for an iCloud container directory. The string you specify must not contain wildcards and must be of the form `<TEAMID>.<CONTAINER>`, where `<TEAMID>` is your development team ID and `<CONTAINER>` is the bundle identifier of the container you want to access.\
+         The container identifiers for your app must be declared in the `com.apple.developer.ubiquity-container-identifiers` array of the `.entitlements` property list file in your Xcode project.\
+         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(!Thread.isMainThread, "LocalFileProvider.init(containerId:) is not recommended to be executed on Main Thread.")
         guard FileManager.default.ubiquityIdentityToken == nil else {
             return nil
@@ -35,13 +48,20 @@ open class CloudFileProvider: LocalFileProvider {
             return nil
         }
         self.containerId = containerId
-        let baseURL = ubiquityURL.standardized.appendingPathComponent("Documents/")
+        self.scope = scope
+        let baseURL: URL
+        if scope == .documents {
+            baseURL = ubiquityURL.standardized.appendingPathComponent("Documents/")
+        } else {
+            baseURL = ubiquityURL.standardized
+        }
+        
         super.init(baseURL: baseURL)
         self.isCoorinating = true
         
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(self.type)", attributes: DispatchQueue.Attributes.concurrent)
+        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
         operation_queue = OperationQueue()
-        operation_queue.name = "FileProvider.\(self.type).Operation"
+        operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
         
         fileManager.url(forUbiquityContainerIdentifier: containerId)
         opFileManager.url(forUbiquityContainerIdentifier: containerId)
@@ -49,12 +69,14 @@ open class CloudFileProvider: LocalFileProvider {
         try? fileManager.createDirectory(at: baseURL, withIntermediateDirectories: true)
     }
     
+    // FIXME: create runloop for dispatch_queue, start query on it
     open override func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
         dispatch_queue.async {
             let pathURL = self.url(of: path)
+            
             let query = NSMetadataQuery()
             query.predicate = NSPredicate(format: "%K BEGINSWITH %@", NSMetadataItemPathKey, pathURL.path)
-            query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope]
+            query.searchScopes = [self.scope.rawValue]
             var finishObserver: NSObjectProtocol?
             finishObserver = NotificationCenter.default.addObserver(forName: NSNotification.Name.NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
                 defer {
@@ -83,13 +105,18 @@ open class CloudFileProvider: LocalFileProvider {
                     }
                 }
                 
+                query.stop()
                 completionHandler(contents, nil)
             })
-            query.start()
+            DispatchQueue.main.async {
+                if !query.start() {
+                    completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
+                }
+            }
         }
     }
     
-    /// iCloud Storage size and free space is unavailable, it returns local space
+    /// - Important: iCloud Storage size and free space is unavailable, it returns local space
     open override func storageProperties(completionHandler: (@escaping (_ total: Int64, _ used: Int64) -> Void)) {
         super.storageProperties(completionHandler: completionHandler)
     }
@@ -99,7 +126,7 @@ open class CloudFileProvider: LocalFileProvider {
             let pathURL = self.url(of: path)
             let query = NSMetadataQuery()
             query.predicate = NSPredicate(format: "%K LIKE %@", NSMetadataItemPathKey, pathURL.path)
-            query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope]
+            query.searchScopes = [self.scope.rawValue]
             var finishObserver: NSObjectProtocol?
             finishObserver = NotificationCenter.default.addObserver(forName: NSNotification.Name.NSMetadataQueryDidFinishGathering, object: query, queue: nil, using: { (notification) in
                 defer {
@@ -122,38 +149,42 @@ open class CloudFileProvider: LocalFileProvider {
                     completionHandler(nil, noFileError)
                 }
             })
-            query.start()
+            DispatchQueue.main.async {
+                if !query.start() {
+                    completionHandler(nil, self.throwError(path, code: CocoaError.fileReadNoPermission))
+                }
+            }
         }
     }
     
     @discardableResult
     open override func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let r = super.create(folder: folderName, at: atPath, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.create(folder: folderName, at: atPath, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let r = super.create(file: fileName, at: atPath, contents: data, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.create(file: fileName, at: atPath, contents: data, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func moveItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let r = super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.moveItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func copyItem(path: String, to toPath: String, overwrite: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let r = super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.copyItem(path: path, to: toPath, overwrite: overwrite, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let r = super.removeItem(path: path, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.removeItem(path: path, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
@@ -204,26 +235,26 @@ open class CloudFileProvider: LocalFileProvider {
             return nil
         }
         
-        let r = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.copyItem(path: path, toLocalURL: toLocalURL, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        let r = super.contents(path: path, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.contents(path: path, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        let r = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        guard let r = super.contents(path: path, offset: offset, length: length, completionHandler: completionHandler) else { return nil }
+        return CloudOperationHandle(operationType: r.operationType, baseURL: self.baseURL)
     }
     
     @discardableResult
     open override func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let r = super.writeContents(path: path, contents: data, atomically: atomically, overwrite: overwrite, completionHandler: completionHandler)
-        return CloudOperationHandle(operationType: r!.operationType, baseURL: self.baseURL)
+        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 searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
@@ -231,7 +262,7 @@ open class CloudFileProvider: LocalFileProvider {
             let pathURL = self.url(of: path)
             let query = NSMetadataQuery()
             query.predicate = NSPredicate(format: "(%K BEGINSWITH %@) && (%K LIKE %@)", NSMetadataItemPathKey, pathURL.path, NSMetadataItemFSNameKey, query)
-            query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope]
+            query.searchScopes = [self.scope.rawValue]
             
             var lastReportedCount = 0
             
@@ -294,18 +325,22 @@ open class CloudFileProvider: LocalFileProvider {
                 completionHandler(contents, nil)
             })
             
-            query.start()
+            DispatchQueue.main.async {
+                if !query.start() {
+                    completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
+                }
+            }
         }
     }
     
-    fileprivate var monitors = [URL: (NSMetadataQuery, NSObjectProtocol)]()
-    //
+    fileprivate var monitors = [String: (NSMetadataQuery, NSObjectProtocol)]()
+    
     open override func registerNotifcation(path: String, eventHandler: @escaping (() -> Void)) {
         self.unregisterNotifcation(path: path)
         let pathURL = self.url(of: path)
         let query = NSMetadataQuery()
         query.predicate = NSPredicate(format: "(%K BEGINSWITH %@)", NSMetadataItemPathKey, pathURL.path)
-        query.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope]
+        query.searchScopes = [self.scope.rawValue]
         
         let updateObserver = NotificationCenter.default.addObserver(forName: .NSMetadataQueryDidUpdate, object: query, queue: nil, using: { (notification) in
             
@@ -316,27 +351,27 @@ open class CloudFileProvider: LocalFileProvider {
             query.enableUpdates()
         })
         
-        query.start()
-        
-        monitors[pathURL] = (query, updateObserver)
+        DispatchQueue.main.async {
+            if query.start() {
+                self.monitors[path] = (query, updateObserver)
+            }
+        }
     }
     
     open override func unregisterNotifcation(path: String) {
-        let key = url(of: path)
-        guard let (query, observer) = monitors[key] else {
+        guard let (query, observer) = monitors[path] else {
             return
         }
         query.disableUpdates()
         query.stop()
-        monitors.removeValue(forKey: key)
         NotificationCenter.default.removeObserver(observer)
+        monitors.removeValue(forKey: path)
     }
     
     open override func isRegisteredForNotification(path: String) -> Bool {
-        return monitors[url(of: path)] != nil
+        return monitors[path] != nil
     }
     
-    /// may return nil
     open override func copy(with zone: NSZone? = nil) -> Any {
         let copy = CloudFileProvider(containerId: self.containerId)
         copy?.currentPath = self.currentPath
@@ -394,6 +429,38 @@ open class CloudFileProvider: LocalFileProvider {
     }
 }
 
+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.
+    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.
+    case documents
+    
+    public typealias RawValue = String
+    
+    public init? (rawValue: String) {
+        switch rawValue {
+        case NSMetadataQueryUbiquitousDataScope:
+            self = .data
+        case NSMetadataQueryUbiquitousDocumentsScope:
+            self = .documents
+        default:
+            return nil
+        }
+    }
+    
+    public var rawValue: String {
+        switch self {
+        case .data:
+            return NSMetadataQueryUbiquitousDataScope
+        case .documents:
+            return NSMetadataQueryUbiquitousDocumentsScope
+        }
+    }
+}
+
 open class CloudOperationHandle: OperationHandle {
     public let baseURL: URL?
     public let operationType: FileOperationType
@@ -413,7 +480,6 @@ open class CloudOperationHandle: OperationHandle {
         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")
         
@@ -431,7 +497,6 @@ open class CloudOperationHandle: OperationHandle {
         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")
         guard let url = destURL ?? sourceURL, let item = CloudOperationHandle.getMetadataItem(url: url) else { return -1 }
@@ -447,18 +512,18 @@ open class CloudOperationHandle: OperationHandle {
     
     /// 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]
+        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 {
@@ -475,8 +540,9 @@ open class CloudOperationHandle: OperationHandle {
             
         })
         
-        group.enter()
-        query.start()
+        DispatchQueue.main.async {
+            query.start()
+        }
         _ = group.wait(timeout: DispatchTime.now() + 30)
         return item
     }

Sources/DropboxFileProvider.swift

@@ -10,16 +10,15 @@
 import Foundation
 import CoreGraphics
 
-// Because this class uses NSURLSession, it's necessary to disable App Transport Security
-// in case of using this class with unencrypted HTTP connection.
-
 open class DropboxFileProvider: FileProviderBasicRemote {
-    open static let type: String = "DropBox"
+    open class var type: String { return "DropBox" }
     open let isPathRelative: Bool
     open let baseURL: URL?
     open var currentPath: String
     
+    /// 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
@@ -48,7 +47,17 @@ open class DropboxFileProvider: FileProviderBasicRemote {
         return _session!
     }
     
-    public init? (credential: URLCredential?, cache: URLCache? = nil) {
+    /**
+     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.
+     
+     - 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. If set to nil, URLCache.shared object will be used.
+    */
+    public init(credential: URLCredential?, cache: URLCache? = nil) {
         self.baseURL = nil
         self.isPathRelative = true
         self.currentPath = ""
@@ -60,14 +69,18 @@ open class DropboxFileProvider: FileProviderBasicRemote {
         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: DispatchQueue.Attributes.concurrent)
+        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
         operation_queue = OperationQueue()
         operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
 
     }
     
     deinit {
-        _session?.invalidateAndCancel()
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
     }
     
     open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
@@ -85,16 +98,16 @@ open class DropboxFileProvider: FileProviderBasicRemote {
         let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
         request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             var fileObject: DropboxFileObject?
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
                 if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr), let file = DropboxFileObject(json: json) {
                     fileObject = file
                 }
             }
-            completionHandler(fileObject, dbError ?? error)
+            completionHandler(fileObject, serverError ?? error)
         }) 
         task.resume()
     }
@@ -120,8 +133,6 @@ open class DropboxFileProvider: FileProviderBasicRemote {
 }
 
 extension DropboxFileProvider: FileProviderOperations {
-    
-    
     public 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)
@@ -176,12 +187,12 @@ extension DropboxFileProvider: FileProviderOperations {
         }
         request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                 dbError = FileProviderDropboxError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+                 serverError = FileProviderDropboxError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
             }
-            completionHandler?(dbError ?? error)
-            self.delegateNotify(operation, error: dbError ?? error)
+            completionHandler?(serverError ?? error)
+            self.delegateNotify(operation, error: serverError ?? error)
         })
         task.taskDescription = operation.json
         task.resume()
@@ -212,8 +223,8 @@ extension DropboxFileProvider: FileProviderOperations {
             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 dbError : FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                completionHandler?(dbError ?? error)
+                let serverError : FileProviderDropboxError? = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
+                completionHandler?(serverError ?? error)
                 return
             }
             do {
@@ -231,7 +242,10 @@ extension DropboxFileProvider: FileProviderOperations {
 
 extension DropboxFileProvider: FileProviderReadWrite {
     public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -248,12 +262,12 @@ extension DropboxFileProvider: FileProviderReadWrite {
         let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
         request.setValue(dictionaryToJSON(requestDictionary), forHTTPHeaderField: "Dropbox-API-Arg")
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             if let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: httpResponse.statusCode) {
-                dbError = FileProviderDropboxError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+                serverError = FileProviderDropboxError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
             }
-            let filedata = dbError ?? error == nil ? data : nil
-            completionHandler(filedata, dbError ?? error)
+            let filedata = serverError ?? error == nil ? data : nil
+            completionHandler(filedata, serverError ?? error)
         })
         task.taskDescription = opType.json
         task.resume()
@@ -292,18 +306,40 @@ extension DropboxFileProvider: FileProviderReadWrite {
         NotImplemented()
     }
     
-    // TODO: Implement /copy_reference, /get_account & /get_current_account
+    // TODO: Implement /get_account & /get_current_account
 }
 
 extension DropboxFileProvider {
-    @available(*, deprecated, message: "Use DropboxFileProvider.temporaryLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
+    /// *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.temporaryLink(to: path) { (url, file, _, error) in
+        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 block 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)) {
         let url = URL(string: "files/get_temporary_link", relativeTo: apiURL)!
         var request = URLRequest(url: url)
         request.httpMethod = "POST"
@@ -312,12 +348,12 @@ extension DropboxFileProvider {
         let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString]
         request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             var link: URL?
             var fileObject: DropboxFileObject?
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
                 if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr) {
                     if let linkStr = json["link"] as? String {
                         link = URL(string: linkStr)
@@ -329,12 +365,27 @@ extension DropboxFileProvider {
             }
             
             let expiration: Date? = link != nil ? Date(timeIntervalSinceNow: 4 * 60 * 60) : nil
-            completionHandler(link, fileObject, expiration, dbError ?? error)
+            completionHandler(link, fileObject, expiration, serverError ?? error)
         })
         task.resume()
     }
     
+    /**
+     Downloads a file from remote url to designated path asynchronously.
+     
+     - Parameters:
+       - remoteURL: a valid remote url to file.
+       - to: Destination path of file, including file/directory name.
+       - completionHandler: a block 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.
+     */
     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))
+            return
+        }
         let url = URL(string: "files/save_url", relativeTo: apiURL)!
         var request = URLRequest(url: url)
         request.httpMethod = "POST"
@@ -343,12 +394,12 @@ extension DropboxFileProvider {
         let requestDictionary: [String: AnyObject] = ["path": correctPath(toPath)! as NSString, "url" : remoteURL.absoluteString as NSString]
         request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             var jobId: String?
             var fileObject: DropboxFileObject?
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
                 if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr) {
                     jobId = json["async_job_id"] as? String
                     if let attribDic = json["metadata"] as? [String: AnyObject] {
@@ -356,13 +407,21 @@ extension DropboxFileProvider {
                     }
                 }
             }
-            completionHandler(jobId, fileObject, dbError ?? error)
+            completionHandler(jobId, fileObject, serverError ?? error)
         })
         task.resume()
     }
     
-    open func copyItem(reference: String, to toPath: String, completionHandler:SimpleCompletionHandler) {
-        let url = URL(string: "files/save_url", relativeTo: apiURL)!
+    /**
+     Copys a file from another user Dropbox storage to designated path asynchronously.
+     
+     - Parameters:
+       - reference: a valid reference string from another user via `copy_reference/get` REST method.
+       - to: Destination path of file, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     */
+    open func copyItem(reference: String, to toPath: String, completionHandler: SimpleCompletionHandler) {
+        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")
@@ -370,12 +429,12 @@ extension DropboxFileProvider {
         let requestDictionary: [String: AnyObject] = ["path": correctPath(toPath)! as NSString, "copy_reference" : reference as NSString]
         request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: toPath, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
             }
-            completionHandler?(dbError ?? error)
+            completionHandler?(serverError ?? error)
         })
         task.resume()
     }
@@ -464,17 +523,17 @@ extension DropboxFileProvider: ExtendedFileProvider {
         let requestDictionary: [String: AnyObject] = ["path": correctPath(path)! as NSString, "include_media_info": NSNumber(value: true)]
         request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderDropboxError?
+            var serverError: FileProviderDropboxError?
             var dic = [String: Any]()
             var keys = [String]()
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderDropboxError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
                 if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr), let properties = json["media_info"] as? [String: Any] {
                     (dic, keys) = self.mapMediaInfo(properties)
                 }
             }
-            completionHandler(dic, keys, dbError ?? error)
+            completionHandler(dic, keys, serverError ?? error)
         })
         task.resume()
     }
@@ -482,7 +541,7 @@ extension DropboxFileProvider: ExtendedFileProvider {
 
 extension DropboxFileProvider: FileProvider {
     open func copy(with zone: NSZone? = nil) -> Any {
-        let copy = DropboxFileProvider(credential: self.credential, cache: self.cache)!
+        let copy = DropboxFileProvider(credential: self.credential, cache: self.cache)
         copy.currentPath = self.currentPath
         copy.delegate = self.delegate
         copy.fileOperationDelegate = self.fileOperationDelegate

Sources/DropboxHelper.swift

@@ -43,28 +43,28 @@ public final class DropboxFileObject: FileObject {
     
     open internal(set) var serverTime: Date? {
         get {
-            return allValues["NSURLServerDateKey"] as? Date
+            return allValues[.serverDate] as? Date
         }
         set {
-            allValues["NSURLServerDateKey"] = newValue
+            allValues[.serverDate] = newValue
         }
     }
     
     open internal(set) var id: String? {
         get {
-            return allValues["NSURLDocumentIdentifyKey"] as? String
+            return allValues[.documentIdentifierKey] as? String
         }
         set {
-            allValues["NSURLDocumentIdentifyKey"] = newValue
+            allValues[.documentIdentifierKey] = newValue
         }
     }
     
     open internal(set) var rev: String? {
         get {
-            return allValues[URLResourceKey.generationIdentifierKey.rawValue] as? String
+            return allValues[.generationIdentifierKey] as? String
         }
         set {
-            allValues[URLResourceKey.generationIdentifierKey.rawValue] = newValue
+            allValues[.generationIdentifierKey] = newValue
         }
     }
 }

Sources/ExtendedLocalFileProvider.swift

@@ -123,25 +123,24 @@ extension LocalFileProvider: ExtendedFileProvider {
             
             completionHandler(dic, keys, nil)
         }
-        
     }
 }
 
 public struct LocalFileInformationGenerator {
-    static public var imageThumbnailExtensions: [String] = ["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]
-    static public var audioThumbnailExtensions: [String] = ["mp3", "aac", "m4a"]
-    static public var videoThumbnailExtensions: [String] = ["mov", "mp4", "m4v", "mpg", "mpeg"]
-    static public var pdfThumbnailExtensions: [String] = ["pdf"]
+    static public var imageThumbnailExtensions: [String]  = ["jpg", "jpeg", "gif", "bmp", "png", "tif", "tiff", "ico"]
+    static public var audioThumbnailExtensions: [String]  = ["mp3", "aac", "m4a"]
+    static public var videoThumbnailExtensions: [String]  = ["mov", "mp4", "m4v", "mpg", "mpeg"]
+    static public var pdfThumbnailExtensions: [String]    = ["pdf"]
     static public var officeThumbnailExtensions: [String] = []
     static public var customThumbnailExtensions: [String] = []
     
-    static public var imagePropertiesExtensions: [String] = ["jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff"]
-    static public var audioPropertiesExtensions: [String] = ["mp3", "aac", "m4a", "caf"]
-    static public var videoPropertiesExtensions: [String] = ["mp4", "mpg", "3gp", "mov", "avi"]
-    static public var pdfPropertiesExtensions: [String] = ["pdf"]
+    static public var imagePropertiesExtensions: [String]   = ["jpg", "jpeg", "bmp", "gif", "png", "tif", "tiff"]
+    static public var audioPropertiesExtensions: [String]   = ["mp3", "aac", "m4a", "caf"]
+    static public var videoPropertiesExtensions: [String]   = ["mp4", "mpg", "3gp", "mov", "avi"]
+    static public var pdfPropertiesExtensions: [String]     = ["pdf"]
     static public var archivePropertiesExtensions: [String] = []
-    static public var officePropertiesExtensions: [String] = []
-    static public var customPropertiesExtensions: [String] = []
+    static public var officePropertiesExtensions: [String]  = []
+    static public var customPropertiesExtensions: [String]  = []
     
     static public var imageThumbnail: (_ fileURL: URL) -> ImageClass? = { fileURL in
         return ImageClass(contentsOfFile: fileURL.path)
@@ -189,6 +188,16 @@ public struct LocalFileInformationGenerator {
     }
     
     static public var imageProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         func simplify(_ top:Int64, _ bottom:Int64) -> (newTop:Int, newBottom:Int) {
             var x = top
             var y = bottom
@@ -203,79 +212,57 @@ public struct LocalFileInformationGenerator {
             return(Int(newTopVal), Int(newBottomVal))
         }
         
-        var dic = [String: Any]()
-        var keys = [String]()
         guard let cgDataRef = CGImageSourceCreateWithURL(fileURL as CFURL, nil), let cfImageDict = CGImageSourceCopyPropertiesAtIndex(cgDataRef, 0, nil) else {
             return (dic, keys)
         }
         let imageDict = cfImageDict as NSDictionary
-        let tiffDict = imageDict[kCGImagePropertyTIFFDictionary as String] as? [String : AnyObject] ?? [:]
-        let exifDict = imageDict[kCGImagePropertyExifDictionary as String] as? [String : AnyObject] ?? [:]
-        if let pixelWidth: AnyObject = imageDict.object(forKey: kCGImagePropertyPixelWidth) as? NSNumber, let pixelHeight: AnyObject = imageDict.object(forKey: kCGImagePropertyPixelHeight) as? NSNumber {
-            keys.append("Dimensions")
-            dic["Dimensions"] = "\(pixelWidth)x\(pixelHeight)"
-        }
-        if let dpi = imageDict[kCGImagePropertyDPIWidth as String] {
-            keys.append("DPI")
-            dic["DPI"] = dpi
-        }
-        if let devicemake = tiffDict[kCGImagePropertyTIFFMake as String] {
-            keys.append("Device make")
-            dic["Device make"] = devicemake
-        }
-        if let devicemodel = tiffDict[kCGImagePropertyTIFFModel as String] {
-            keys.append("Device model")
-            dic["Device model"] = devicemodel
-        }
-        if let lensmodel = exifDict[kCGImagePropertyExifLensModel as String] {
-            keys.append("Lens model")
-            dic["Lens model"] = lensmodel
-        }
-        if let artist = tiffDict[kCGImagePropertyTIFFArtist as String] as? String , !artist.isEmpty {
-            keys.append("Artist")
-            dic["Artist"] = artist
+        let tiffDict = imageDict[kCGImagePropertyTIFFDictionary as String] as? NSDictionary ?? [:]
+        let exifDict = imageDict[kCGImagePropertyExifDictionary as String] as? NSDictionary ?? [:]
+        if let pixelWidth = imageDict.object(forKey: kCGImagePropertyPixelWidth) as? NSNumber, let pixelHeight = imageDict.object(forKey: kCGImagePropertyPixelHeight) as? NSNumber {
+            add(key: "Dimensions", value: "\(pixelWidth)x\(pixelHeight)")
         }
+        
+        add(key: "DPI", value: imageDict[kCGImagePropertyDPIWidth as String])
+        add(key: "Device make", value: tiffDict[kCGImagePropertyTIFFMake as String])
+        add(key: "Device model", value: tiffDict[kCGImagePropertyTIFFModel as String])
+        add(key: "Lens model", value: exifDict[kCGImagePropertyExifLensModel as String])
+        add(key: "Artist", value: tiffDict[kCGImagePropertyTIFFArtist as String] as? String)
         if let cr = tiffDict[kCGImagePropertyTIFFCopyright as String] as? String , !cr.isEmpty {
-            keys.append("Copyright")
-            dic["Copyright"] = cr
+            add(key: "Copyright", value: cr)
+
         }
         if let date = tiffDict[kCGImagePropertyTIFFDateTime as String] as? String , !date.isEmpty {
-            keys.append("Date taken")
-            dic["Date taken"] = date
+            add(key: "Date taken", value: date)
         }
-        if let latitude = tiffDict[kCGImagePropertyGPSLatitude as String]?.doubleValue, let longitude = tiffDict[kCGImagePropertyGPSLongitude as String]?.doubleValue {
-            keys.append("Location")
-            dic["Location"] = "\(latitude), \(longitude)"
+        if let latitude = tiffDict[kCGImagePropertyGPSLatitude as String] as? NSNumber, let longitude = tiffDict[kCGImagePropertyGPSLongitude as String] as? NSNumber {
+            add(key: "Location", value: "\(latitude), \(longitude)")
         }
-        if let colorspace = imageDict[kCGImagePropertyColorModel as String] {
-            keys.append("Color space")
-            dic["Color space"] = colorspace
-        }
-        if let focallen = exifDict[kCGImagePropertyExifFocalLength as String] {
-            keys.append("Focal length")
-            dic["Focal length"] = focallen
-        }
-        if let fnum = exifDict[kCGImagePropertyExifFNumber as String] {
-            keys.append("F number")
-            dic["F number"] = fnum
-        }
-        if let expprog = exifDict[kCGImagePropertyExifExposureProgram as String] {
-            keys.append("Exposure program")
-            dic["Exposure program"] = expprog
-        }
-        if let exp = exifDict[kCGImagePropertyExifExposureTime as String]?.doubleValue {
-            let expfrac = simplify(Int64(exp * 10_000_000_000_000), 10_000_000_000_000)
-            keys.append("Exposure time")
-            dic["Exposure time"] = "\(expfrac.newTop)/\(expfrac.newBottom)"
+        add(key: "Color space", value: imageDict[kCGImagePropertyColorModel as String])
+        add(key: "Focal length", value: exifDict[kCGImagePropertyExifFocalLength as String])
+        add(key: "F number", value: exifDict[kCGImagePropertyExifFNumber as String])
+        add(key: "Exposure program", value: exifDict[kCGImagePropertyExifExposureProgram as String])
+        
+        if let exp = exifDict[kCGImagePropertyExifExposureTime as String] as? NSNumber {
+            let expfrac = simplify(Int64(exp.doubleValue * 10_000_000_000_000), 10_000_000_000_000)
+            add(key: "Exposure time", value: "\(expfrac.newTop)/\(expfrac.newBottom)")
         }
         if let iso = exifDict[kCGImagePropertyExifISOSpeedRatings as String] as? NSArray , iso.count > 0 {
-            keys.append("ISO speed")
-            dic["ISO speed"] = iso[0]
+            add(key: "ISO speed", value: iso[0])
         }
         return (dic, keys)
     }
     
     static var audioProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         func makeDescription(_ key: String?) -> String? {
             guard let key = key else {
                 return nil
@@ -287,8 +274,6 @@ public struct LocalFileInformationGenerator {
             return newKey.capitalized
         }
         
-        var dic = [String: Any]()
-        var keys = [String]()
         if FileManager.default.fileExists(atPath: fileURL.path) {
             let playerItem = AVPlayerItem(url: fileURL)
             let metadataList = playerItem.asset.commonMetadata
@@ -301,12 +286,8 @@ public struct LocalFileInformationGenerator {
                 }
             }
             if let ap = try? AVAudioPlayer(contentsOf: fileURL) {
-                keys.append("Duration")
-                dic["Duration"] = LocalFileProvider.formatshort(interval: ap.duration)
-                if let bitRate = ap.settings[AVSampleRateKey] as? Int {
-                    keys.append("Bitrate")
-                    dic["Bitrate"] = bitRate
-                }
+                add(key: "Duration", value: LocalFileProvider.formatshort(interval: ap.duration))
+                add(key: "Bitrate", value: ap.settings[AVSampleRateKey] as? Int)
             }
         }
         return (dic, keys)
@@ -315,6 +296,14 @@ public struct LocalFileInformationGenerator {
     static public var videoProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
         var dic = [String: Any]()
         var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         if let audioprops = LocalFileInformationGenerator.audioProperties?(fileURL) {
             dic = audioprops.prop
             keys = audioprops.keys
@@ -329,17 +318,14 @@ public struct LocalFileInformationGenerator {
             var bitrate: Float = 0
             let width = Int(videoTracks[0].naturalSize.width)
             let height = Int(videoTracks[0].naturalSize.height)
-            keys.append("Dimensions")
-            dic["Dimensions"] = "\(width)x\(height)"
+            add(key: "Dimensions", value: "\(width)x\(height)")
             var duration: Int64 = 0
             for track in videoTracks {
                 duration += track.timeRange.duration.timescale > 0 ? track.timeRange.duration.value / Int64(track.timeRange.duration.timescale) : 0
                 bitrate += track.estimatedDataRate
             }
-            keys.append("Duration")
-            dic["Duration"] = LocalFileProvider.formatshort(interval: TimeInterval(duration))
-            keys.append("Video Bitrate")
-            dic["Video Bitrate"] = "\(Int(ceil(bitrate / 1000))) kbps"
+            add(key: "Duration", value: LocalFileProvider.formatshort(interval: TimeInterval(duration)))
+            add(key: "Video Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
         }
         let audioTracks = asset.tracks(withMediaType: AVMediaTypeAudio)
         // dic["Audio channels"] = audioTracks.count
@@ -347,12 +333,21 @@ public struct LocalFileInformationGenerator {
         for track in audioTracks {
             bitrate += track.estimatedDataRate
         }
-        keys.append("Audio Bitrate")
-        dic["Audio Bitrate"] = "\(Int(ceil(bitrate / 1000))) kbps"
+        add(key: "Audio Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
         return (dic, keys)
     }
     
     static public var pdfProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         func getKey(_ key: String, from dict: CGPDFDictionaryRef) -> String? {
             var cfValue: CGPDFStringRef? = nil
             if (CGPDFDictionaryGetString(dict, key, &cfValue)), let value = CGPDFStringCopyTextString(cfValue!) {
@@ -378,56 +373,40 @@ public struct LocalFileInformationGenerator {
             return nil
         }
         
-        var dic = [String: Any]()
-        var keys = [String]()
         if let data = try? Data(contentsOf: fileURL), let provider = CGDataProvider(data: data as CFData), let reference = CGPDFDocument(provider), let dict = reference.info {
             if let title = getKey("Title", from: dict), !title.isEmpty {
-                keys.append("Title")
-                dic["Title"] = title
+                add(key: "Title", value: title)
             }
             if let author = getKey("Author", from: dict), !author.isEmpty {
-                keys.append("Author")
-                dic["Author"] = author
+                add(key: "Author", value: author)
             }
             if let subject = getKey("Subject", from: dict), !subject.isEmpty {
-                keys.append("Subject")
-                dic["Subject"] = subject
+                add(key: "Subject", value: subject)
             }
             var majorVersion: Int32 = 0
             var minorVersion: Int32 = 0
             reference.getVersion(majorVersion: &majorVersion, minorVersion: &minorVersion)
             if majorVersion > 0 {
-                keys.append("Version")
-                dic["Version"] = String(majorVersion) + "." + String(minorVersion)
-            }
-            if reference.numberOfPages > 0 {
-                keys.append("Pages")
-                dic["Pages"] = reference.numberOfPages
+                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
-                keys.append("Resolution")
-                dic["Resolution"] = "\(Int(size.width))x\(Int(size.height))"
+                add(key: "Resolution", value: "\(Int(size.width))x\(Int(size.height))")
             }
             if let creator = getKey("Creator", from: dict), !creator.isEmpty {
-                keys.append("Content creator")
-                dic["Content creator"] = creator
+                add(key: "Content creator", value: creator)
             }
-            if let creationDateString = getKey("CreationDate", from: dict), let creationDate = convertDate(creationDateString) {
-                keys.append("Creation date")
-                dic["Creation date"] = creationDate
+            if let creationDateString = getKey("CreationDate", from: dict) {
+                add(key: "Creation date", value: convertDate(creationDateString))
             }
-            if let modifiedDateString = getKey("ModDate", from: dict), let modDate = convertDate(modifiedDateString) {
-                keys.append("Modified date")
-                dic["Modified date"] = modDate
+            if let modifiedDateString = getKey("ModDate", from: dict) {
+                add(key: "Modified date", value: convertDate(modifiedDateString))
             }
-            keys.append("Security")
-            dic["Security"] = reference.isEncrypted ? "Present" : "None"
-            keys.append("Allows printing")
-            dic["Allows printing"] = reference.allowsPrinting ? "Yes" : "No"
-            keys.append("Allows copying")
-            dic["Allows copying"] = reference.allowsCopying ? "Yes" : "No"
+            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")
         }
         return (dic, keys)
     }
@@ -439,6 +418,6 @@ public struct LocalFileInformationGenerator {
     static public var customProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = nil
 }
 
-func ~=<T : Equatable>(array: [T], value: T) -> Bool {
+fileprivate func ~=<T : Equatable>(array: [T], value: T) -> Bool {
     return array.contains(value)
 }

Sources/FileObject.swift

@@ -11,95 +11,98 @@ import Foundation
 /// Containts path and attributes of a file or resource.
 open class FileObject {
     /// A `Dictionary` contains file information,  using `URLResourceKey` keys.
-    open internal(set) var allValues: [String: Any]
+    open internal(set) var allValues: [URLResourceKey: Any]
     
-    internal init(allValues: [String: Any]) {
+    internal init(allValues: [URLResourceKey: Any]) {
         self.allValues = allValues
     }
     
     internal init(url: URL, name: String, path: String) {
-        self.allValues = [String: Any]()
+        self.allValues = [URLResourceKey: Any]()
         self.url = url
         self.name = name
         self.path = path
     }
     
     /// url to access the resource, not supported by Dropbox provider
-    @available(*, deprecated, message: "Use FileObject.url.absoluteURL instead.")
+    @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? {
         get {
-            return allValues["NSURLFileURLKey"] as? URL
+            return allValues[.fileURL] as? URL
         }
         set {
-            allValues["NSURLFileURLKey"] = newValue
+            allValues[.fileURL] = newValue
         }
     }
     
     /// Name of the file, usually equals with the last path component
     open internal(set) var name: String {
         get {
-            return allValues[URLResourceKey.nameKey.rawValue] as! String
+            return allValues[.nameKey] as! String
         }
         set {
-            allValues[URLResourceKey.nameKey.rawValue] = newValue
+            allValues[.nameKey] = newValue
         }
     }
     
     /// Relative path of file object
     open internal(set) var path: String {
         get {
-            return allValues[URLResourceKey.pathKey.rawValue] as! String
+            return allValues[.pathKey] as! String
         }
         set {
-            allValues[URLResourceKey.pathKey.rawValue] = newValue
+            allValues[.pathKey] = newValue
         }
     }
     
     /// Size of file on disk, return -1 for directories.
     open internal(set) var size: Int64 {
         get {
-            return allValues[URLResourceKey.fileSizeKey.rawValue] as? Int64 ?? -1
+            return allValues[.fileSizeKey] as? Int64 ?? -1
         }
         set {
-            allValues[URLResourceKey.fileSizeKey.rawValue] = newValue
+            allValues[.fileSizeKey] = newValue
         }
     }
     
     /// The time contents of file has been created, returns nil if not set
     open internal(set) var creationDate: Date? {
         get {
-            return allValues[URLResourceKey.creationDateKey.rawValue] as? Date
+            return allValues[.creationDateKey] as? Date
         }
         set {
-            allValues[URLResourceKey.creationDateKey.rawValue] = newValue
+            allValues[.creationDateKey] = newValue
         }
     }
     
     /// The time contents of file has been modified, returns nil if not set
     open internal(set) var modifiedDate: Date? {
         get {
-            return allValues[URLResourceKey.contentModificationDateKey.rawValue] as? Date
+            return allValues[.contentModificationDateKey] as? Date
         }
         set {
-            allValues[URLResourceKey.contentModificationDateKey.rawValue] = newValue
+            allValues[.contentModificationDateKey] = newValue
         }
     }
     
     /// return resource type of file, usually directory, regular or symLink
     open internal(set) var type: URLFileResourceType? {
         get {
-            return allValues[URLResourceKey.fileResourceTypeKey.rawValue] as? URLFileResourceType
+            return allValues[.fileResourceTypeKey] as? URLFileResourceType
         }
         set {
-            allValues[URLResourceKey.fileResourceTypeKey.rawValue] = newValue
+            allValues[.fileResourceTypeKey] = newValue
         }
     }
     
-    @available(*, deprecated, message: "Use FileObject.type property instead.")
+    /// **OBSOLETED:** Use `type` property instead.
+    @available(*, obsoleted: 1.0, renamed: "type", message: "Use type property instead.")
     open var fileType: URLFileResourceType? {
         return self.type
     }
@@ -108,20 +111,20 @@ open class FileObject {
     /// Setting this value on a file begining with dot has no effect
     open internal(set) var isHidden: Bool {
         get {
-            return allValues[URLResourceKey.isHiddenKey.rawValue] as? Bool ?? false
+            return allValues[.isHiddenKey] as? Bool ?? false
         }
         set {
-            allValues[URLResourceKey.isHiddenKey.rawValue] = newValue
+            allValues[.isHiddenKey] = newValue
         }
     }
     
     /// File can not be written
     open internal(set) var isReadOnly: Bool {
         get {
-            return !(allValues[URLResourceKey.isWritableKey.rawValue] as? Bool ?? true)
+            return !(allValues[.isWritableKey] as? Bool ?? true)
         }
         set {
-            allValues[URLResourceKey.isWritableKey.rawValue] = !newValue
+            allValues[.isWritableKey] = !newValue
         }
     }
     
@@ -293,6 +296,13 @@ extension URLFileResourceType {
     }
 }
 
+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 ?? ""

Sources/FileProvider.swift

@@ -111,8 +111,10 @@ public extension FileProviderBasic {
     }
 }
 
+public var fileProviderCancelTasksOnInvalidating = true
+
 public protocol FileProviderBasicRemote: FileProviderBasic {
-    ///
+    /// Underlying URLSession instance used for HTTP/S requests
     var session: URLSession { get }
     
     /// A `URLCache` to cache downloaded files and contents.
@@ -177,6 +179,7 @@ internal extension FileProviderBasicRemote {
 }
 
 public protocol FileProviderOperations: FileProviderBasic {
+    /// Delgate for managing operations involving the copying, moving, linking, or removal of files and directories. When you use an FileManager object to initiate a copy, move, link, or remove operation, the file provider asks its delegate whether the operation should begin at all and whether it should proceed when an error occurs.
     var fileOperationDelegate : FileOperationDelegate? { get set }
     
     /**
@@ -489,6 +492,42 @@ public protocol FileProviderMonitor: FileProviderBasic {
     func isRegisteredForNotification(path: String) -> Bool
 }
 
+public protocol FileProvideUndoable: FileProviderOperations {
+    var undoManager: UndoManager? { get set }
+    
+    func canUndo(handle: OperationHandle) -> Bool
+    func canUndo(operation: FileOperationType) -> Bool
+}
+
+public extension FileProvideUndoable {
+    public func canUndo(operation: FileOperationType) -> Bool {
+        return undoOperation(for: operation) != nil
+    }
+    
+    public func canUndo(handle: OperationHandle) -> Bool {
+        return canUndo(operation: handle.operationType)
+    }
+    
+    internal func undoOperation(for operation: FileOperationType) -> FileOperationType? {
+        switch operation {
+        case .create(path: let path):
+            return .remove(path: path)
+        case .modify(path: _):
+            return nil
+        case .copy(source: _, destination: let dest):
+            return .remove(path: dest)
+        case .move(source: let source, destination: let dest):
+            return .move(source: dest, destination: source)
+        case .link(link: let link, target: _):
+            return .remove(path: link)
+        case .remove(path: _):
+            return nil
+        default:
+            return nil
+        }
+    }
+}
+
 public protocol FileProvider: FileProviderBasic, FileProviderOperations, FileProviderReadWrite, NSCopying {
 }
 
@@ -507,7 +546,8 @@ extension FileProviderBasic {
         return path.trimmingCharacters(in: pathTrimSet).addingPercentEncoding(withAllowedCharacters: .urlPathAllowed)!
     }
     
-    @available(*, deprecated, message: "Use FileProvider.url(of:).absoluteURL instead.")
+    /// **OBSOLETED:** Use `url(of:).absoluteURL` instead.
+    @available(*, obsoleted: 1.0, renamed: "url(of:)", message: "Use url(of:).absoluteURL instead.")
     public func absoluteURL(_ path: String? = nil) -> URL {
         return url(of: path).absoluteURL
     }
@@ -530,12 +570,21 @@ extension FileProviderBasic {
         }
     }
     
+    
+    /// 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 {
-        if url.baseURL == self.baseURL {
+        // check if url derieved from current base url
+        if url.relativeString.isEmpty, url.baseURL == self.baseURL {
             return url.relativePath.removingPercentEncoding!
         }
         
-        guard let baseURL = self.baseURL else { return url.absoluteString }
+        // resolve url string against baseurl
+        guard let baseURL = self.baseURL?.standardizedFileURL else { return url.absoluteString }
         return url.standardizedFileURL.absoluteString.replacingOccurrences(of: baseURL.absoluteString, with: "/").removingPercentEncoding!
     }
     

Sources/LocalFileProvider.swift

@@ -8,8 +8,8 @@
 
 import Foundation
 
-open class LocalFileProvider: FileProvider, FileProviderMonitor {
-    open static let type: String = "Local"
+open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndoable {
+    open class var type: String { return "Local" }
     open var isPathRelative: Bool
     open fileprivate(set) var baseURL: URL?
     open var currentPath: String
@@ -22,17 +22,43 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     open private(set) var opFileManager = FileManager()
     fileprivate var fileProviderManagerDelegate: LocalFileProviderManagerDelegate? = nil
     
-    /// Forces file operations to use NSFileCoordinating, should be set true if:
-    /// - Files are on ubiquity(iCloud) container
-    /// - Multiple processes are accessing same file, recommended always in macOS and when using app extensions in iOS/tvOS (shared container)
+    open var undoManager: UndoManager? = nil
+    
+    /**
+     Forces file operations to use `NSFileCoordinating`, should be set `true` if:
+     - Files are on ubiquity (iCloud) container.
+     - Multiple processes are accessing same file, recommended when accessing a shared/public 
+     user document in macOS and when using app extensions in iOS/tvOS (shared container).
+     
+     By default it's `true` when using iCloud or shared container (App Group) initializers,
+     otherwise it's `false` to accelerate operations.
+    */
     open var isCoorinating: Bool
     
-    /// default values are `directory: .documentDirectory, domainMask: .userDomainMask`
+    /**
+     Initializes provider for the specified common directory in the requested domains.
+     default values are `directory: .documentDirectory, domainMask: .userDomainMask`.
+     
+     - Parameters:
+       - directory: The search path directory. The supported values are described in `FileManager.SearchPathDirectory`.
+       - domainMask: The file system domain to search. The value for this parameter is one or more of the constants described in `FileManager.SearchPathDomainMask`.
+    */
     public convenience init (directory: FileManager.SearchPathDirectory = .documentDirectory, domainMask: FileManager.SearchPathDomainMask = .userDomainMask) {
         self.init(baseURL: FileManager.default.urls(for: directory, in: domainMask).first!)
     }
     
-    public convenience init ? (sharedContainerId: String, directory: FileManager.SearchPathDirectory = .userDirectory) {
+    /**
+     Failable initializer for the specified shared container directory, allows data and files to be shared among app
+     and extensions regarding sandbox requirements. Container ID is same with app group specified in project `Capabilities`
+     tab under `App Group` item. If you don't have enough privilage to access container or the app group imply does't exist,
+     initialing will fail.
+     default values are `directory: .documentDirectory`.
+    
+     - Parameters:
+       - sharedContainerId: Same  with `App Group` identifier defined in project settings.
+       - directory: The search path directory. The supported values are described in `FileManager.SearchPathDirectory`.
+    */
+    public convenience init? (sharedContainerId: String, directory: FileManager.SearchPathDirectory = .documentDirectory) {
         guard let baseURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: sharedContainerId) else {
             return nil
         }
@@ -57,14 +83,20 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
         try? fileManager.createDirectory(at: finalBaseURL, withIntermediateDirectories: true)
     }
     
+    /// Initializes provider for the specified local URL.
+    ///
+    /// - Parameter baseURL: Local URL location for base directory.
     public init (baseURL: URL) {
+        guard baseURL.isFileURL else {
+            fatalError("Cannot initialize a Local provider from remote URL.")
+        }
         self.baseURL = baseURL
         self.isPathRelative = true
         self.currentPath = ""
         self.credential = nil
         self.isCoorinating = false
         
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: DispatchQueue.Attributes.concurrent)
+        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
         operation_queue = OperationQueue()
         operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
         
@@ -73,6 +105,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
         
     }
     
+    /// **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!
@@ -81,7 +114,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     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: [.nameKey, .fileSizeKey, .fileAllocatedSizeKey, .creationDateKey, .contentModificationDateKey, .isHiddenKey, .volumeIsReadOnlyKey], options: .skipsSubdirectoryDescendants)
+                let contents = try self.fileManager.contentsOfDirectory(at: self.url(of: path), includingPropertiesForKeys: nil, options: .skipsSubdirectoryDescendants)
                 let filesAttributes = contents.flatMap({ (fileURL) -> LocalFileObject? in
                     let path = self.relativePathOf(url: fileURL)
                     return LocalFileObject(fileWithPath: path, relativeTo: self.baseURL)
@@ -94,9 +127,9 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     }
     
     open func storageProperties(completionHandler: (@escaping (_ total: Int64, _ used: Int64) -> Void)) {
-        let dict = (try? FileManager.default.attributesOfFileSystem(forPath: baseURL?.path ?? "/"))
-        let totalSize = (dict?[.systemSize] as? NSNumber)?.int64Value ?? -1;
-        let freeSize = (dict?[.systemFreeSize] as? NSNumber)?.int64Value ?? 0;
+        let values = try? baseURL?.resourceValues(forKeys: [.volumeTotalCapacityKey, .volumeAvailableCapacityKey])
+        let totalSize = Int64(values??.volumeTotalCapacity ?? -1)
+        let freeSize = Int64(values??.volumeAvailableCapacity ?? 0)
         completionHandler(totalSize, totalSize - freeSize)
     }
     
@@ -111,245 +144,165 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     @discardableResult
     open func create(folder folderName: String, at atPath: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(folderName) + "/")
-        let url = self.url(of: atPath).appendingPathComponent(folderName)
-        
-        let operationHandler: (URL) -> Void = { url in
-            do {
-                try self.opFileManager.createDirectory(at: url, withIntermediateDirectories: true, attributes: [:])
-                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        }
-        
-        if isCoorinating {
-            let intent = NSFileAccessIntent.writingIntent(with: url, options: .forReplacing)
-            self.coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
-                completionHandler?(error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            })
-        } else {
-            operation_queue.addOperation {
-                operationHandler(url)
-            }
-        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return self.doOperation(opType, completionHandler: completionHandler)
     }
     
     @discardableResult
     open func create(file fileName: String, at atPath: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
-        let opType = FileOperationType.create(path: (atPath as NSString).appendingPathComponent(fileName))
-        let url = self.url(of: atPath).appendingPathComponent(fileName, isDirectory: false)
+        let fileName = fileName.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
+        let path = (atPath as NSString).appendingPathComponent(fileName)
+        let opType = FileOperationType.create(path: path)
         
-        let operationHandler: (URL) -> Void = { url in
-            let success = self.opFileManager.createFile(atPath: url.path, contents: data, attributes: nil)
-            if success {
-                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } else {
-                completionHandler?(self.throwError(atPath, code: URLError.cannotCreateFile as FoundationErrorEnum))
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        }
-        
-        if isCoorinating {
-            let intent = NSFileAccessIntent.writingIntent(with:url, options: .forReplacing)
-            self.coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
-                completionHandler?(error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            })
-        } else {
-            operation_queue.addOperation {
-                operationHandler(url)
-            }
-        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        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)
-        let sourceUrl = self.url(of: path)
-        let destUrl = self.url(of: toPath)
-        
-        let sourceIntent = NSFileAccessIntent.writingIntent(with: sourceUrl, options: .forDeleting)
-        let destIntent = NSFileAccessIntent.writingIntent(with: destUrl, options: .forReplacing)
-        
-        let operationHandler: (URL, URL) -> Void = { sourceUrl, destUrl in
-            if !overwrite && self.fileManager.fileExists(atPath: destUrl.path) {
-                completionHandler?(self.throwError(toPath, code: URLError.cannotMoveFile as FoundationErrorEnum))
-                return
-            }
-            do {
-                try self.opFileManager.moveItem(at: sourceUrl, to: destUrl)
-                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
+
+        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
+            completionHandler?(self.throwError(toPath, code: URLError.cannotMoveFile as FoundationErrorEnum))
+            return nil
         }
         
-        if isCoorinating {
-            coordinated(intents: [sourceIntent, destIntent], completionHandler: operationHandler) { (error) in
-                completionHandler?(error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        } else {
-            operation_queue.addOperation {
-                operationHandler(sourceUrl, destUrl)
-            }
-        }
-        
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        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)
-        let sourceUrl = self.url(of: path)
-        let destUrl = self.url(of: toPath)
         
-        let sourceIntent = NSFileAccessIntent.readingIntent(with: sourceUrl, options: .withoutChanges)
-        let destIntent = NSFileAccessIntent.writingIntent(with: destUrl, options: .forDeleting)
-        
-        let operationHandler: (URL, URL) -> Void = { sourceUrl, destUrl in
-            if !overwrite && self.fileManager.fileExists(atPath: destUrl.path) {
-                completionHandler?(self.throwError(toPath, code: URLError.cannotMoveFile as FoundationErrorEnum))
-                return
-            }
-            do {
-                try self.opFileManager.copyItem(at: sourceUrl, to: destUrl)
-                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
+        if !overwrite && self.fileManager.fileExists(atPath: self.url(of: toPath).path) {
+            completionHandler?(self.throwError(toPath, code: URLError.cannotWriteToFile as FoundationErrorEnum))
+            return nil
         }
         
-        if isCoorinating {
-            coordinated(intents: [sourceIntent, destIntent], moving: true, completionHandler: operationHandler) { (error) in
-                completionHandler?(error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        } else {
-            operation_queue.addOperation {
-                operationHandler(sourceUrl, destUrl)
-            }
-        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return self.doOperation(opType, completionHandler: completionHandler)
     }
     
     @discardableResult
     open func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.remove(path: path)
-        let url = self.url(of: path)
-        
-        let operationHandler: (URL) -> Void = { url in
-            do {
-                let successfulSecurityScopedResourceAccess = url.startAccessingSecurityScopedResource()
-                try self.opFileManager.removeItem(at: url)
-                if successfulSecurityScopedResourceAccess {
-                    url.stopAccessingSecurityScopedResource()
-                }
-                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        }
-        
-        if isCoorinating {
-            let intent = NSFileAccessIntent.writingIntent(with:url, options: .forReplacing)
-            self.coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
-                completionHandler?(error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            })
-        } else {
-            operation_queue.addOperation {
-                operationHandler(url)
-            }
-        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return self.doOperation(opType, completionHandler: completionHandler)
     }
     
     @discardableResult
     open func copyItem(localFile: URL, to toPath: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         // TODO: Make use of overwrite parameter
         let opType = FileOperationType.copy(source: localFile.absoluteString, destination: toPath)
-        operation_queue.addOperation {
-            do {
-                try self.opFileManager.copyItem(at: localFile, to: self.url(of: toPath))
-                completionHandler?(nil)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        }
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return self.doOperation(opType, completionHandler: completionHandler)
     }
     
     @discardableResult
     open func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.copy(source: path, destination: toLocalURL.absoluteString)
-        operation_queue.addOperation {
+        return self.doOperation(opType, completionHandler: completionHandler)
+    }
+    
+    dynamic func doSimpleOperation(_ box: UndoBox) {
+        _ = self.doOperation(box.operation) { (_) in
+            return
+        }
+    }
+    
+    @discardableResult
+    fileprivate func doOperation(_ opType: FileOperationType, data: Data? = nil, atomically: Bool = false, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
+        guard let sourcePath = opType.source else { return nil }
+        let destPath = opType.destination
+        let source: URL, dest: URL?
+        
+        if sourcePath.hasPrefix("file://") {
+            source = URL(string: sourcePath)!
+        } else {
+            source = self.url(of: sourcePath)
+        }
+        
+        if let destPath = destPath {
+            if destPath.hasPrefix("file://") {
+                dest = URL(string: destPath)!
+            } else {
+                dest = self.url(of: destPath)
+            }
+        } else {
+            dest = nil
+        }
+        
+        let operationHandler: (URL, URL?) -> Void = { source, dest in
+            let successfulSecurityScopedResourceAccess = source.startAccessingSecurityScopedResource()
             do {
-                try self.opFileManager.copyItem(at: self.url(of: path), to: toLocalURL)
+                switch opType {
+                case .create:
+                    if sourcePath.hasSuffix("/") {
+                        try self.opFileManager.createDirectory(at: source, withIntermediateDirectories: true, attributes: [:])
+                    } else {
+                        try data?.write(to: source, options: Data.WritingOptions.atomic)
+                    }
+                case .modify:
+                    try data?.write(to: source, options: atomically ? [.atomic] : [])
+                case .copy:
+                    guard let dest = dest else { return }
+                    try self.opFileManager.copyItem(at: source, to: dest)
+                case .move:
+                    guard let dest = dest else { return }
+                    try self.opFileManager.moveItem(at: source, to: dest)
+                case.remove:
+                    try self.opFileManager.removeItem(at: source)
+                default:
+                    return
+                }
+                if successfulSecurityScopedResourceAccess {
+                    source.stopAccessingSecurityScopedResource()
+                }
+                
+                if let undoOp = self.undoOperation(for: opType) {
+                    let undoBox = UndoBox(provider: self, operation: undoOp)
+                    self.undoManager?.registerUndo(withTarget: self, selector: #selector(LocalFileProvider.doSimpleOperation(_:)), object: undoBox)
+                }
+                
                 completionHandler?(nil)
                 DispatchQueue.main.async {
                     self.delegate?.fileproviderSucceed(self, operation: opType)
                 }
             } catch let e {
+                if successfulSecurityScopedResourceAccess {
+                    source.stopAccessingSecurityScopedResource()
+                }
                 completionHandler?(e)
                 DispatchQueue.main.async {
                     self.delegate?.fileproviderFailed(self, operation: opType)
                 }
             }
         }
+        
+        if isCoorinating {
+            var intents = [NSFileAccessIntent]()
+            
+            switch opType {
+            case .create, .remove, .modify:
+                intents.append(NSFileAccessIntent.writingIntent(with: source, options: .forReplacing))
+            case .copy:
+                guard let dest = dest else { return nil }
+                intents.append(NSFileAccessIntent.readingIntent(with: source, options: .withoutChanges))
+                intents.append(NSFileAccessIntent.writingIntent(with: dest, options: .forReplacing))
+            case .move:
+                guard let dest = dest else { return nil }
+                intents.append(NSFileAccessIntent.writingIntent(with: source, options: .forDeleting))
+                intents.append(NSFileAccessIntent.writingIntent(with: dest, options: .forReplacing))
+            default:
+                return nil
+            }
+            self.coordinated(intents: intents, completionHandler: operationHandler, errorHandler: { error in
+                completionHandler?(error)
+                DispatchQueue.main.async {
+                    self.delegate?.fileproviderFailed(self, operation: opType)
+                }
+            })
+        } else {
+            operation_queue.addOperation {
+                operationHandler(source, dest)
+            }
+        }
+        
         return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
     }
     
@@ -386,7 +339,10 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     
     @discardableResult
     open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -399,11 +355,11 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
         
         let operationHandler: (URL) -> Void = { url in
             guard self.fileManager.fileExists(atPath: url.path) && !url.fileIsDirectory else {
-                completionHandler(nil, self.throwError(path, code: URLError.fileDoesNotExist as FoundationErrorEnum))
+                completionHandler(nil, self.throwError(path, code: CocoaError.fileNoSuchFile as FoundationErrorEnum))
                 return
             }
             guard let handle = FileHandle(forReadingAtPath: url.path) else {
-                completionHandler(nil, self.throwError(path, code: URLError.cannotOpenFile as FoundationErrorEnum))
+                completionHandler(nil, self.throwError(path, code: CocoaError.fileReadNoPermission as FoundationErrorEnum))
                 return
             }
             
@@ -446,45 +402,7 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     @discardableResult
     open func writeContents(path: String, contents data: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle? {
         let opType = FileOperationType.modify(path: path)
-        let url = self.url(of: path)
-        var options: Data.WritingOptions = []
-        if atomically {
-            options.insert(.atomic)
-        }
-        if overwrite {
-            options.insert(.withoutOverwriting)
-        }
-        
-        let operationHandler: (URL) -> Void = { url in
-            do {
-                try data.write(to: url, options: atomically ? [.atomic] : [])
-                completionHandler?(nil)
-                DispatchQueue.main.async{
-                    self.delegate?.fileproviderSucceed(self, operation: opType)
-                }
-            } catch let e {
-                completionHandler?(e)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            }
-        }
-        
-        if isCoorinating {
-            let intent = NSFileAccessIntent.writingIntent(with: url, options: .forReplacing)
-            coordinated(intents: [intent], completionHandler: operationHandler, errorHandler: { error in
-                completionHandler?(error)
-                DispatchQueue.main.async {
-                    self.delegate?.fileproviderFailed(self, operation: opType)
-                }
-            })
-        } else {
-            operation_queue.addOperation {
-                operationHandler(url)
-            }
-        }
-        
-        return LocalOperationHandle(operationType: opType, baseURL: self.baseURL)
+        return self.doOperation(opType, data: data, atomically: atomically, completionHandler: completionHandler)
     }
     
     open func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void)) {
@@ -549,6 +467,17 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
 }
 
 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.
+    
+     - 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.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+    */
     public func create(symbolicLink path: String, withDestinationPath destPath: String, completionHandler: SimpleCompletionHandler) {
         operation_queue.addOperation {
             do {
@@ -566,6 +495,11 @@ public extension LocalFileProvider {
         }
     }
     
+    /// Returns the path of the item pointed to by a symbolic link.
+    ///
+    /// - 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) {
         dispatch_queue.async {
             do {
@@ -591,19 +525,21 @@ internal extension LocalFileProvider {
         }
     }
     
-    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, completionHandler: @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 {
                 errorHandler?(error)
                 return
             }
-            if moving {
-                coordinator.item(at: intents[0].url, willMoveTo: intents[1].url)
+            let newSource: URL = intents[0].url
+            let newDest: URL? = intents.count > 1 ? intents[1].url : nil
+            if moving, let newDest = newDest {
+                coordinator.item(at: newSource, willMoveTo: newDest)
             }
-            completionHandler(intents[0].url, intents[1].url)
-            if moving {
-                coordinator.item(at: intents[0].url, didMoveTo: intents[1].url)
+            completionHandler(newSource, newDest)
+            if moving, let newDest = newDest {
+                coordinator.item(at: newSource, didMoveTo: newDest)
             }
         }
     }

Sources/LocalHelper.swift

@@ -37,12 +37,12 @@ public final class LocalFileObject: FileObject {
     
     public convenience init?(fileWithURL fileURL: URL) {
         do {
-            let values = try fileURL.resourceValues(forKeys: [.nameKey, .fileSizeKey, .fileAllocatedSizeKey, .creationDateKey, .contentModificationDateKey, .fileResourceTypeKey, .isHiddenKey, .isWritableKey, .typeIdentifierKey, .generationIdentifierKey])
+            let values = try fileURL.resourceValues(forKeys: [.nameKey, .fileSizeKey, .fileAllocatedSizeKey, .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)
             for (key, value) in values.allValues {
-                self.allValues[key.rawValue] = value
+                self.allValues[key] = value
             }
         } catch {
             return nil
@@ -51,23 +51,31 @@ public final class LocalFileObject: FileObject {
     
     open internal(set) var allocatedSize: Int64 {
         get {
-            return allValues[URLResourceKey.fileAllocatedSizeKey.rawValue] as? Int64 ?? 0
+            return allValues[.fileAllocatedSizeKey] as? Int64 ?? 0
         }
         set {
-            allValues[URLResourceKey.fileAllocatedSizeKey.rawValue] = Int(exactly: newValue) ?? Int.max
+            allValues[.fileAllocatedSizeKey] = Int(exactly: newValue) ?? Int.max
+        }
+    }
+    
+    open internal(set) var id: Int? {
+        get {
+            return allValues[.documentIdentifierKey] as? Int
+        }
+        set {
+            allValues[.documentIdentifierKey] = newValue
         }
     }
     
     open var rev: String? {
         get {
-            let data = allValues[URLResourceKey.generationIdentifierKey.rawValue] as? Data
+            let data = allValues[.generationIdentifierKey] as? Data
             return data?.map { String(format: "%02hhx", $0) }.joined()
         }
     }
-
 }
 
-internal class LocalFolderMonitor {
+internal final class LocalFolderMonitor {
     fileprivate let source: DispatchSourceFileSystemObject
     fileprivate let descriptor: CInt
     fileprivate let qq: DispatchQueue = DispatchQueue.global(qos: .default)
@@ -297,6 +305,16 @@ open class LocalOperationHandle: OperationHandle {
     }
 }
 
+class UndoBox: NSObject {
+    weak var provider: FileProvideUndoable?
+    let operation: FileOperationType
+    
+    init(provider: FileProvideUndoable, operation: FileOperationType) {
+        self.provider = provider
+        self.operation = operation
+    }
+}
+
 internal extension URL {
     var fileIsDirectory: Bool {
         return (try? self.resourceValues(forKeys: [.isDirectoryKey]))?.isDirectory ?? false

Sources/OneDriveFileProvide.swift

@@ -10,15 +10,15 @@
 import Foundation
 import CoreGraphics
 
-// Because this class uses NSURLSession, it's necessary to disable App Transport Security
-// in case of using this class with unencrypted HTTP connection.
-
 open class OneDriveFileProvider: FileProviderBasicRemote {
-    open static let type: String = "OneDrive"
+    open class var type: String { return "OneDrive" }
     open let isPathRelative: Bool
     open let baseURL: URL?
+    /// OneDrive server url, equals with unwrapped `baseURL`
     open var serverURL: URL { return baseURL! }
+    /// 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 driveURL: URL {
         return URL(string: "/drive/\(drive):/", relativeTo: baseURL)!
     }
@@ -52,7 +52,21 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
         return _session!
     }
     
-    public init? (credential: URLCredential?, serverURL: URL? = nil, drive: String = "root", cache: URLCache? = nil) {
+    /**
+     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. If set to nil, URLCache.shared object will be used.
+     */
+    public init(credential: URLCredential?, serverURL: URL? = nil, drive: String = "root", cache: URLCache? = nil) {
         self.baseURL = (serverURL ?? URL(string: "https://api.onedrive.com/")!).appendingPathComponent("")
         self.drive = drive
         self.isPathRelative = true
@@ -61,13 +75,17 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
         self.validatingCache = true
         self.cache = cache
         self.credential = credential
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: DispatchQueue.Attributes.concurrent)
+        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
         operation_queue = OperationQueue()
         operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
     }
     
     deinit {
-        _session?.invalidateAndCancel()
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
     }
     
     open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
@@ -82,16 +100,16 @@ open class OneDriveFileProvider: FileProviderBasicRemote {
         request.httpMethod = "GET"
         request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderOneDriveError?
+            var serverError: FileProviderOneDriveError?
             var fileObject: OneDriveFileObject?
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
                 if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr), let file = OneDriveFileObject(baseURL: self.baseURL, drive: self.drive, json: json) {
                     fileObject = file
                 }
             }
-            completionHandler(fileObject, dbError ?? error)
+            completionHandler(fileObject, serverError ?? error)
         }) 
         task.resume()
     }
@@ -170,12 +188,12 @@ extension OneDriveFileProvider: FileProviderOperations {
             request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
         }
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderOneDriveError?
+            var serverError: FileProviderOneDriveError?
             if let response = response as? HTTPURLResponse, response.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: response.statusCode) {
-                 dbError = FileProviderOneDriveError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+                 serverError = FileProviderOneDriveError(code: code, path: sourcePath, errorDescription: String(data: data ?? Data(), encoding: .utf8))
             }
-            completionHandler?(dbError ?? error)
-            self.delegateNotify(operation, error: dbError ?? error)
+            completionHandler?(serverError ?? error)
+            self.delegateNotify(operation, error: serverError ?? error)
         })
         task.taskDescription = operation.json
         task.resume()
@@ -203,8 +221,8 @@ extension OneDriveFileProvider: FileProviderOperations {
             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 dbError : FileProviderOneDriveError? = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
-                completionHandler?(dbError ?? error)
+                let serverError : FileProviderOneDriveError? = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: errorData ?? Data(), encoding: .utf8)) : nil
+                completionHandler?(serverError ?? error)
                 return
             }
             do {
@@ -222,7 +240,10 @@ extension OneDriveFileProvider: FileProviderOperations {
 
 extension OneDriveFileProvider: FileProviderReadWrite {
     public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -237,12 +258,12 @@ extension OneDriveFileProvider: FileProviderReadWrite {
             request.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
         }
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderOneDriveError?
+            var serverError: FileProviderOneDriveError?
             if let httpResponse = response as? HTTPURLResponse , httpResponse.statusCode >= 300, let code = FileProviderHTTPErrorCode(rawValue: httpResponse.statusCode) {
-                dbError = FileProviderOneDriveError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
+                serverError = FileProviderOneDriveError(code: code, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8))
             }
-            let filedata = dbError ?? error == nil ? data : nil
-            completionHandler(filedata, dbError ?? error)
+            let filedata = serverError ?? error == nil ? data : nil
+            completionHandler(filedata, serverError ?? error)
         })
         task.taskDescription = opType.json
         task.resume()
@@ -281,7 +302,40 @@ extension OneDriveFileProvider: FileProviderReadWrite {
         NotImplemented()
     }
     
-    // TODO: Implement /copy_reference, /get_account & /get_current_account
+    /**
+     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 block 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)) {
+        let url =  URL(string: escaped(path: path) + ":/action.createLink", relativeTo: driveURL)!
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        let requestDictionary: [String: AnyObject] = ["type": "view" as NSString]
+        request.httpBody = dictionaryToJSON(requestDictionary)?.data(using: .utf8)
+        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 data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr) {
+                    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()
+    }
 }
 
 
@@ -335,17 +389,17 @@ extension OneDriveFileProvider: ExtendedFileProvider {
         request.httpMethod = "GET"
         request.setValue("Bearer \(credential?.password ?? "")", forHTTPHeaderField: "Authorization")
         let task = session.dataTask(with: request, completionHandler: { (data, response, error) in
-            var dbError: FileProviderOneDriveError?
+            var serverError: FileProviderOneDriveError?
             var dic = [String: Any]()
             var keys = [String]()
             if let response = response as? HTTPURLResponse {
                 let code = FileProviderHTTPErrorCode(rawValue: response.statusCode)
-                dbError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
+                serverError = code != nil ? FileProviderOneDriveError(code: code!, path: path, errorDescription: String(data: data ?? Data(), encoding: .utf8)) : nil
                 if let data = data, let jsonStr = String(data: data, encoding: .utf8), let json = jsonToDictionary(jsonStr) {
                     (dic, keys) = self.mapMediaInfo(json)
                 }
             }
-            completionHandler(dic, keys, dbError ?? error)
+            completionHandler(dic, keys, serverError ?? error)
         })
         task.resume()
     }
@@ -353,7 +407,7 @@ extension OneDriveFileProvider: ExtendedFileProvider {
 
 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)!
+        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

Sources/OneDriveHelper.swift

@@ -48,28 +48,28 @@ public final class OneDriveFileObject: FileObject {
     
     open internal(set) var id: String? {
         get {
-            return allValues["NSURLDocumentIdentifyKey"] as? String
+            return allValues[.documentIdentifierKey] as? String
         }
         set {
-            allValues["NSURLDocumentIdentifyKey"] = newValue
+            allValues[.documentIdentifierKey] = newValue
         }
     }
     
     open internal(set) var contentType: String {
         get {
-            return allValues["NSURLContentTypeKey"] as? String ?? ""
+            return allValues[.mimeType] as? String ?? ""
         }
         set {
-            allValues["NSURLContentTypeKey"] = newValue
+            allValues[.mimeType] = newValue
         }
     }
     
     open internal(set) var entryTag: String? {
         get {
-            return allValues["NSURLEntryTagKey"] as? String
+            return allValues[.entryTag] as? String
         }
         set {
-            allValues["NSURLEntryTagKey"] = newValue
+            allValues[.entryTag] = newValue
         }
     }
 }
@@ -235,72 +235,51 @@ internal extension OneDriveFileProvider {
         var dic = [String: Any]()
         var keys = [String]()
         
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         if let parent = json["image"] as? [String: Any] ?? json["video"] as? [String: Any], let height = parent["height"] as? UInt64, let width = parent["width"] as? UInt64 {
-            keys.append("Dimensions")
-            dic["Dimensions"] = "\(width)x\(height)"
+            add(key: "Dimensions", value: "\(width)x\(height)")
         }
         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
-            keys.append("Location")
             let latStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: latitude))
             let longStr = OneDriveFileProvider.decimalFormatter.string(from: NSNumber(value: longitude))
-            dic["Location"] = "\(latStr), \(longStr)"
+            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 {
-            keys.append("Duration")
-            dic["Duration"] = OneDriveFileProvider.formatshort(interval: TimeInterval(duration) / 1000)
+            add(key: "Duration", value: OneDriveFileProvider.formatshort(interval: TimeInterval(duration) / 1000))
         }
         if let timeTakenStr = json["takenDateTime"] as? String, let timeTaken = resolve(dateString: timeTakenStr) {
-            keys.append("Date taken")
             OneDriveFileProvider.dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
-            dic["Date taken"] = OneDriveFileProvider.dateFormatter.string(from: timeTaken)
+            add(key: "Date taken", value:  OneDriveFileProvider.dateFormatter.string(from: timeTaken))
         }
         
         if let photo = json["photo"] as? [String: Any] {
-            if let devicemake = photo["cameraMake"] as? String {
-                keys.append("Device make")
-                dic["Device make"] = devicemake
-            }
-            if let devicemodel = photo["cameraModel"] as? String {
-                keys.append("Device model")
-                dic["Device model"] = devicemodel
-            }
-            if let focallen = photo["focalLength"] as? Double {
-                keys.append("Focal length")
-                dic["Focal length"] = focallen
-            }
-            if let fnum = photo["fNumber"] as? Double {
-                keys.append("F number")
-                dic["F number"] = fnum
-            }
+            add(key: "Device make", value: photo["cameraMake"] as? String)
+            add(key: "Device model", value: photo["cameraModel"] as? String)
+            add(key: "focalLength", value: photo["focalLength"] as? Double)
+            add(key: "fNumber", value: photo["fNumber"] as? Double)
             if let expNom = photo["exposureNumerator"] as? Double, let expDen = photo["exposureDenominator"] as? Double {
-                keys.append("Exposure time")
-                dic["Exposure time"] = "\(Int(expNom))/\(Int(expDen))"
+                add(key: "Exposure time", value: "\(Int(expNom))/\(Int(expDen))")
             }
-            if let iso = photo["iso"] as? Int64 {
-                keys.append("ISO speed")
-                dic["ISO speed"] = iso
-            }
-
+            add(key: "ISO speed", value: photo["iso"] as? Int64)
         }
         
         if let audio = json["audio"] as? [String: Any] {
             for (key, value) in audio {
                 if key == "bitrate" || key == "isVariableBitrate" { continue }
                 let casedKey = spaceCamelCase(key)
-                keys.append(casedKey)
-                dic[casedKey] = value
+                add(key: casedKey, value: value)
             }
         }
         
-        if let video = json["video"] as? [String: Any] {
-            if let bitRate = video["bitrate"] as? Int {
-                keys.append("Bitrate")
-                dic["Bitrate"] = bitRate
-            }
-        }
+        add(key: "Bitrate", value: (json["video"] as? NSDictionary)?["bitrate"] as? Int)
         
         return (dic, keys)
     }

Sources/SMBFileProvider.swift

@@ -9,8 +9,7 @@
 import Foundation
 
 class SMBFileProvider: FileProvider, FileProviderMonitor {
-
-    open static var type: String = "Samba"
+    open class var type: String { return "SMB" }
     open var isPathRelative: Bool = true
     open var baseURL: URL?
     open var currentPath: String = ""
@@ -26,7 +25,7 @@ class SMBFileProvider: FileProvider, FileProviderMonitor {
             return nil
         }
         self.baseURL = baseURL.appendingPathComponent("")
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: DispatchQueue.Attributes.concurrent)
+        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
         operation_queue = OperationQueue()
         operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
         

Sources/WebDAVFileProvider.swift

@@ -12,7 +12,7 @@ import Foundation
 /// in case of using this class with unencrypted HTTP connection.
 
 open class WebDAVFileProvider: FileProviderBasicRemote {
-    open static let type: String = "WebDAV"
+    open class var type: String { return "WebDAV" }
     open let isPathRelative: Bool
     open let baseURL: URL?
     open var currentPath: String
@@ -45,6 +45,14 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         return _session!
     }
     
+    /**
+     Initializes WebDAV provider.
+     
+     - Parameters:
+       - baseURL: Location of WebDAV server.
+       - credential: An `URLCredential` object with `user` and `password`.
+       - cache: A URLCache to cache downloaded files and contents. If set to nil, URLCache.shared object will be used.
+    */
     public init? (baseURL: URL, credential: URLCredential?, cache: URLCache? = nil) {
         if  !["http", "https"].contains(baseURL.uw_scheme.lowercased()) {
             return nil
@@ -56,13 +64,17 @@ open class WebDAVFileProvider: FileProviderBasicRemote {
         self.validatingCache = true
         self.cache = cache
         self.credential = credential
-        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: DispatchQueue.Attributes.concurrent)
+        dispatch_queue = DispatchQueue(label: "FileProvider.\(type(of: self).type)", attributes: .concurrent)
         operation_queue = OperationQueue()
         operation_queue.name = "FileProvider.\(type(of: self).type).Operation"
     }
     
     deinit {
-        _session?.invalidateAndCancel()
+        if fileProviderCancelTasksOnInvalidating {
+            _session?.invalidateAndCancel()
+        } else {
+            _session?.finishTasksAndInvalidate()
+        }
     }
     
     open func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void)) {
@@ -319,7 +331,10 @@ extension WebDAVFileProvider: FileProviderOperations {
 extension WebDAVFileProvider: FileProviderReadWrite {
     @discardableResult
     public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -567,20 +582,20 @@ public final class WebDavFileObject: FileObject {
     /// MIME type of the file
     open internal(set) var contentType: String {
         get {
-            return allValues["NSURLContentTypeKey"] as? String ?? ""
+            return allValues[.mimeType] as? String ?? ""
         }
         set {
-            allValues["NSURLContentTypeKey"] = newValue
+            allValues[.mimeType] = newValue
         }
     }
     
     /// HTTP E-Tag, can be used to mark changed files
     open internal(set) var entryTag: String? {
         get {
-            return allValues["NSURLEntryTagKey"] as? String
+            return allValues[.entryTag] as? String
         }
         set {
-            allValues["NSURLEntryTagKey"] = newValue
+            allValues[.entryTag] = newValue
         }
     }
 }