Fixed undo manager bugs

- Fixed contents of file with offset method bugs
- Improved `LocalFileProvider.copy()` implementation

.travis.yml

@@ -3,30 +3,44 @@ 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   - brew outdated carthage || brew upgrade carthage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+  - brew outdated carthage || brew upgrade carthage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 build --no-skip-current --verbose
   - 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      = "0.11.4"
+  s.version      = "0.12.4"
   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 = 0.11.4;
+				BUNDLE_VERSION_STRING = 0.12.4;
 				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 = 0.11.4;
+				BUNDLE_VERSION_STRING = 0.12.4;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2016 Amir Abbas Mousavian
+Copyright (c) 2016-17 Amir Abbas Mousavian
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -3,15 +3,18 @@
 >This Swift library provide a swifty way to deal with local and remote files and directories in a unified way.
 
 [![Swift Version][swift-image]][swift-url]
-[![Platform](https://img.shields.io/badge/Platform-iOS%2C%20macOS%2C%20tvOS-lightgray.svg)](#)
+[![Platform][platform-image]](#)
 [![License][license-image]][license-url]
 
-[![release badge][release-image]][release-url]
-[![CocoaPods Compatible](https://img.shields.io/cocoapods/v/FileProvider.svg)](https://cocoapods.org/pods/FileProvider)
-[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?)](https://github.com/Carthage/Carthage)
+[![Release versin][release-image]][release-url]
+[![CocoaPods version](https://img.shields.io/cocoapods/v/FileProvider.svg)][cocoapods]
+[![Carthage compatible][carthage-image]](https://github.com/Carthage/Carthage)
 
 [![Build Status][travis-image]][travis-url]
-[![codebeat badge][codebeat-image]][codebeat-url]
+[![Codebeat Badge][codebeat-image]][codebeat-url]
+[![Cocoapods Docs][docs-image]][docs-url]
+[![Cocoapods Downloads][cocoapods-downloads]][cocoapods]
+[![Cocoapods Apps][cocoapods-apps]][cocoapods]
 
 <!--- 
 [![codecov](https://codecov.io/gh/amosavian/FileProvider/branch/master/graph/badge.svg)](https://codecov.io/gh/amosavian/FileProvider) 
@@ -26,18 +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
 
@@ -66,7 +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
@@ -138,7 +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
 
@@ -326,13 +329,56 @@ let data = "What's up Newyork!".data(encoding: .utf8)
 documentsProvider.writeContents(path: "old.txt", content: data, atomically: true, completionHandler: nil)
 ```
 
+### Undo Operations
+
+Providers conform to `FileProviderUndoable` can perform undo for **some** operations like moving/renaming, copying and creating (file or folder). **Now, only `LocalFileProvider` supports this feature.** To implement:
+
+```swift
+// To setup a new UndoManager:
+documentsProvider.setupUndoManager()
+// or if you have an UndoManager object already:
+documentsProvider.undoManager = self.undoManager
+
+// e.g.: To undo last operation manually:
+documentsProvider.undoManager?.undo()
+``` 
+
+You can also bind `UndoManager` object with view controller to use shake gesture and builtin undo support in iOS/macOS, add these code to your ViewController class like this sample code:
+
+```swift
+class ViewController: UIViewController
+    override var canBecomeFirstResponder: Bool {
+        return true
+    }
+    
+    override var undoManager: UndoManager? {
+        return (provider as? FileProvideUndoable)?.undoManager
+    }
+    
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        // Your code here
+        UIApplication.shared.applicationSupportsShakeToEdit = true
+        self.becomeFirstResponder()
+    }
+    
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        // Your code here
+        UIApplication.shared.applicationSupportsShakeToEdit = false
+        self.resignFirstResponder()
+    }
+    // The rest of your implementation
+}
+```
+
 ### Operation Handle
 
 Creating/Copying/Deleting functions return a `OperationHandle` for remote operations. It provides operation type, progress and a `.cancel()` method which allows you to cancel operation in midst.
 
 It's not supported by native `(NS)FileManager` so `LocalFileProvider`, but this functionality will be added to future `PosixFileProvider` class.
 
-### Monitoring FIle Changes
+### Monitoring File Changes
 
 You can monitor updates in some file system (Local and SMB2), there is three methods in supporting provider you can use to register a handler, to unregister and to check whether it's being monitored or not. It's useful to find out when new files added or removed from directory and update user interface. The handler will be dispatched to main threads to avoid UI bugs with a 0.25 sec delay.
 
@@ -405,13 +451,20 @@ Distributed under the MIT license. See `LICENSE` for more information.
 
 [https://github.com/amosavian/](https://github.com/amosavian/)
 
-[swift-image]:https://img.shields.io/badge/swift-3.0-orange.svg
+[cocoapods]: https://cocoapods.org/pods/FileProvider
+[swift-image]: https://img.shields.io/badge/swift-3.0-orange.svg
 [swift-url]: https://swift.org/
-[license-image]: https://img.shields.io/badge/License-MIT-blue.svg
+[platform-image]: https://img.shields.io/cocoapods/p/FileProvider.svg
+[license-image]: https://img.shields.io/github/license/amosavian/FileProvider.svg
 [license-url]: LICENSE
 [codebeat-image]: https://codebeat.co/badges/7b359f48-78eb-4647-ab22-56262a827517
 [codebeat-url]: https://codebeat.co/projects/github-com-amosavian-fileprovider
 [travis-image]: https://img.shields.io/travis/amosavian/FileProvider/master.svg
 [travis-url]: https://travis-ci.org/amosavian/FileProvider
 [release-url]: https://github.com/amosavian/FileProvider/releases
-[release-image]: https://img.shields.io/github/release/amosavian/FileProvider.svg
+[release-image]: https://img.shields.io/github/release/amosavian/FileProvider.svg
+[carthage-image]: https://img.shields.io/badge/Carthage-compatible-4BC51D.svg
+[cocoapods-downloads]: https://img.shields.io/cocoapods/dt/FileProvider.svg
+[cocoapods-apps]: https://img.shields.io/cocoapods/at/FileProvider.svg
+[docs-image]: https://img.shields.io/cocoapods/metrics/doc-percent/FileProvider.svg
+[docs-url]: http://cocoadocs.org/docsets/FileProvider/

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
@@ -366,7 +401,9 @@ open class CloudFileProvider: LocalFileProvider {
         return file
     }
     
-    /// Removes local copy of file, but spares cloud copy
+    /// Removes local copy of file, but spares cloud copy/
+    /// - Parameter path: Path of file or directory to be remoed from local
+    /// - Parameter completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
     open func evictItem(path: String, completionHandler: SimpleCompletionHandler) {
         operation_queue.addOperation {
             do {
@@ -378,6 +415,7 @@ open class CloudFileProvider: LocalFileProvider {
         }
     }
     
+    /// Returns a pulic url with expiration date, can be shared with other people.
     open func temporaryLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: FileObject?, _ expiration: Date?, _ error: Error?) -> Void)) {
         operation_queue.addOperation {
             do {
@@ -391,6 +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
@@ -410,7 +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")
         
@@ -428,7 +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 }
@@ -444,18 +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 {
@@ -472,8 +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 {
@@ -231,6 +242,13 @@ 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 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
+            return nil
+        }
+        
         let opType = FileOperationType.fetch(path: path)
         let url = URL(string: "files/download", relativeTo: contentURL)!
         var request = URLRequest(url: url)
@@ -244,12 +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()
@@ -288,18 +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"
@@ -308,12 +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)
@@ -325,12 +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"
@@ -339,12 +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] {
@@ -352,13 +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")
@@ -366,12 +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()
     }
@@ -460,17 +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()
     }
@@ -478,7 +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

@@ -61,6 +61,7 @@ extension LocalFileProvider: ExtendedFileProvider {
     }
     
     public func thumbnailOfFile(path: String, dimension: CGSize? = nil, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void)) {
+        let dimension = dimension ?? CGSize(width: 64, height: 64)
         (dispatch_queue).async {
             var thumbnailImage: ImageClass? = nil
             // Check cache
@@ -85,7 +86,7 @@ extension LocalFileProvider: ExtendedFileProvider {
             }
             
             if let image = thumbnailImage {
-                let scaledImage = dimension != nil ? LocalFileProvider.scaleDown(image: image, toSize: dimension!) : image
+                let scaledImage = LocalFileProvider.scaleDown(image: image, toSize: dimension)
                 completionHandler(scaledImage, nil)
             }
         }
@@ -122,25 +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)
@@ -188,6 +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
@@ -202,79 +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
@@ -286,8 +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
@@ -300,12 +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)
@@ -314,6 +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
@@ -328,17 +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
@@ -346,12 +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!) {
@@ -377,56 +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)
     }
@@ -438,6 +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

@@ -10,95 +10,99 @@ import Foundation
 
 /// Containts path and attributes of a file or resource.
 open class FileObject {
-    open internal(set) var allValues: [String: Any]
+    /// A `Dictionary` contains file information,  using `URLResourceKey` keys.
+    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
     }
@@ -107,20 +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
         }
     }
     
@@ -215,13 +219,19 @@ public struct FileObjectSorting {
     public static let createdAscending = FileObjectSorting(type: .creationDate, ascending: true)
     public static let createdDesceding = FileObjectSorting(type: .creationDate, ascending: false)
     
+    /// Initializes a `FileObjectSorting` allows to sort an `Array` of `FileObject`.
+    ///
+    /// - Parameters:
+    ///   - type: Determines to sort based on which file property.
+    ///   - ascending: `true` of resulting `Array` is ascending
+    ///   - isDirectoriesFirst: Puts directoris on the top of resulting `Array`.
     public init (type: SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) {
         self.sortType = type
         self.ascending = ascending
         self.isDirectoriesFirst = isDirectoriesFirst
     }
     
-    /// Sorts array of FileObjects by criterias set in properties
+    /// Sorts array of `FileObject`s by criterias set in properties
     public func sort(_ files: [FileObject]) -> [FileObject] {
         return files.sorted {
             if isDirectoriesFirst {
@@ -259,11 +269,13 @@ public struct FileObjectSorting {
 }
 
 extension Array where Element: FileObject {
+    /// Returns a sorted array of `FileObject`s by criterias set in properties.
     public func sorted(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) -> [Element] {
         let sorting = FileObjectSorting(type: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
         return sorting.sort(self) as! [Element]
     }
     
+    /// Sorts array of `FileObject`s by criterias set in properties
     public mutating func sorted(by type: FileObjectSorting.SortType, ascending: Bool = true, isDirectoriesFirst: Bool = false) {
         self = self.sorted(by: type, ascending: ascending, isDirectoriesFirst: isDirectoriesFirst)
     }
@@ -284,6 +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

@@ -18,25 +18,89 @@ public typealias ImageClass = NSImage
 public typealias SimpleCompletionHandler = ((_ error: Error?) -> Void)?
 
 public protocol FileProviderBasic: class {
+    /// An string to identify type of provider.
     static var type: String { get }
+    
+    /// An string to identify type of provider.
     var type: String { get }
+    
+    /// The paths in arguments should resolved against base url.
     var isPathRelative: Bool { get }
+    
+    /// The url of which paths should resolve against.
     var baseURL: URL? { get }
+    
+    /// Current active path used in `contentsOfDirectory(path:completionHandler:)` method.
     var currentPath: String { get set }
+    
+    /**
+     Dispatch queue usually used in query methods.
+     Set it to a new object to switch between cuncurrent and serial queues.
+     - **Default:** Cuncurrent `DispatchQueue` object.
+    */
     var dispatch_queue: DispatchQueue { get set }
+    
+    /// Operation queue ususlly used in file operation methods.
+    /// use `maximumOperationTasks` property of provider to manage operation queue.
     var operation_queue: OperationQueue { get set }
+    
+    /// Delegate to update UI after finishing file operations.
     var delegate: FileProviderDelegate? { get set }
+    
+    /**
+     login credential for provider. Should be set in `init` method.
+     
+     **Example initialization:**
+     ````
+     let credential = URLCredential(user: "user", password: "password", persistence: .forSeession)
+     ````
+     
+     - Note: In OAuth based providers like `DropboxFileProvider` and `OneDriveFileProvider`, password is Token.
+     use [OAuthSwift](https://github.com/OAuthSwift/OAuthSwift) library to fetch clientId and Token of user.
+     */
     var credential: URLCredential? { get }
     
+    /**
+     Returns an Array of `FileObject`s identifying the the directory entries via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty array.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter completionHandler: a block with result of directory entries or error.
+        `contents`: An array of `FileObject` identifying the the directory entries.
+        `error`: Error returned by system.
+     */
     func contentsOfDirectory(path: String, completionHandler: @escaping ((_ contents: [FileObject], _ error: Error?) -> Void))
+    
+    /**
+     Returns a `FileObject` containing the attributes of the item (file, directory, symlink, etc.) at the path in question via asynchronous completion handler.
+     
+     If the directory contains no entries or an error is occured, this method will return the empty `FileObject`.
+     
+     - Parameter path: path to target directory. If empty, `currentPath` value will be used.
+     - Parameter completionHandler: a block with result of directory entries or error.
+        `attributes`: A `FileObject` containing the attributes of the item.
+        `error`: Error returned by system.
+     */
     func attributesOfItem(path: String, completionHandler: @escaping ((_ attributes: FileObject?, _ error: Error?) -> Void))
     
+    
+    /// Returns total and used space in provider container asynchronously.
     func storageProperties(completionHandler: @escaping ((_ total: Int64, _ used: Int64) -> Void))
     
+    /**
+     Returns an independent url to access the file. Some providers like `Dropbox` due to their nature.
+     don't return an absolute url to be used to access file directly.
+     - Parameter path: Relative path of file or directory.
+     - Returns: An url, can be used to access to file directly.
+    */
     func url(of path: String?) -> URL
 }
 
 public extension FileProviderBasic {
+    /// The maximum number of queued operations that can execute at the same time.
+    ///
+    /// The default value of this property is `OperationQueue.defaultMaxConcurrentOperationCount`.
     public var maximumOperationTasks: Int {
         get {
             return operation_queue.maxConcurrentOperationCount
@@ -47,10 +111,22 @@ 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.
+    ///
+    /// If set to nil, `URLCache.shared` object will be used.
+    /// - Note: It has no effect unless setting `useCache` property to `true`.
     var cache: URLCache? { get }
+    
+    /// Determine to use `cache` property to cache downloaded file objects. Doesn't have effect on query type methods.
     var useCache: Bool { get set }
+    
+    /// Validating cached data using E-Tag or Revision identifier if possible.
     var validatingCache: Bool { get set }
 }
 
@@ -103,26 +179,143 @@ 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 }
     
+    /**
+     Creates a new directory at the specified path asynchronously. 
+     This will create any necessary intermediate directories.
+     
+     - Parameters:
+       - folder: Directory name.
+       - at: Parent path of new directory.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     */
     @discardableResult
     func create(folder: String, at: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Creates an new file with data passed to method asynchronously. 
+     Returns error via completionHandler if file is already exists.
+     
+     - Parameters:
+       - file: New file name with extension separated by period.
+       - at: Parent path of new file.
+       - data: Data of new files. Pass nil or `Data()` to create empty file.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
+    
     func create(file: String, at: String, contents data: Data?, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Moves a file or directory from `path` to designated path asynchronously.
+     When you want move a file, destination path should also consists of file name.
+     Either a new name or the old one. If file is already exist, an error will be returned via completionHandler.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - to: destination path of file or directory, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func moveItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Moves a file or directory from `path` to designated path asynchronously.
+     When you want move a file, destination path should also consists of file name.
+     Either a new name or the old one.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - to: destination path of file or directory, including file/directory name.
+       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func moveItem(path: String, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Copies a file or directory from `path` to designated path asynchronously.
+     When want copy a file, destination path should also consists of file name.
+     Either a new name or the old one. If file is already exist, an error will be returned via completionHandler.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - to: destination path of file or directory, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func copyItem(path: String, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Copies a file or directory from `path` to designated path asynchronously.
+     When want copy a file, destination path should also consists of file name.
+     Either a new name or the old one.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - to: destination path of file or directory, including file/directory name.
+       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func copyItem(path: String, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Removes the file or directory at the specified path.
+     
+     - Parameters:
+       - path: file or directory path.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     
+     */
     @discardableResult
     func removeItem(path: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Uploads a file from local file url to designated path asynchronously.
+     Method will fail if source is not a local url with `file://` scheme.
+     
+     - Parameters:
+       - localFile: a file url to file.
+       - to: destination path of file, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress.
+     */
     @discardableResult
     func copyItem(localFile: URL, to: String, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Uploads a file from local file url to designated path asynchronously.
+     Method will fail if source is not a local url with `file://` scheme.
+     
+     - Parameters:
+       - localFile: a file url to file.
+       - to: destination path of file, including file/directory name.
+       - overwrite: Destination file should be overwritten if file is already exists. **Default** is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress.
+     */
     @discardableResult
     func copyItem(localFile: URL, to: String, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Download a file from `path` to designated local file url asynchronously.
+     Method will fail if destination is not a local url with `file://` scheme.
+     
+     - Parameters:
+       - path: original file or directory path.
+       - toLocalURL: destination local url of file, including file/directory name.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func copyItem(path: String, toLocalURL: URL, completionHandler: SimpleCompletionHandler) -> OperationHandle?
 }
@@ -145,20 +338,104 @@ extension FileProviderOperations {
 }
 
 public protocol FileProviderReadWrite: FileProviderBasic {
+    /**
+     Retreives a `Data` object with the contents of the file asynchronously vis contents argument of completion handler.
+     If path specifies a directory, or if some other error occurs, data will be nil.
+     
+     - Parameters:
+       - path: Path of file.
+       - completionHandler: a block with result of file contents or error.
+         `contents`: contents of file in a `Data` object.
+         `error`: Error returned by system.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+    */
     @discardableResult
     func contents(path: String, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle?
+    
+    /**
+     Retreives a `Data` object with a portion contents of the file asynchronously vis contents argument of completion handler.
+     If path specifies a directory, or if some other error occurs, data will be nil.
+     
+     - Parameters:
+       - path: Path of file.
+       - offset: First byte index which should be read. **Starts from 0.**
+       - length: Bytes count of data. Pass `-1` to read until the end of file.
+       - completionHandler: a block with result of file contents or error.
+         `contents`: contents of file in a `Data` object.
+         `error`: Error returned by system.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle?
     
+    /**
+     Write the contents of the `Data` to a location asynchronously.
+     It will return error if file is already exists.
+     Not attomically by default, unless the provider enforces it.
+     
+     - Parameters:
+       - path: Path of target file.
+       - contents: Data to be written into file.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func writeContents(path: String, contents: Data, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Write the contents of the `Data` to a location asynchronously.
+     It will return error if file is already exists.
+     
+     - Parameters:
+       - path: Path of target file.
+       - contents: Data to be written into file.
+       - atomically: data will be written to a temporary file before writing to final location. Default is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func writeContents(path: String, contents: Data, atomically: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Write the contents of the `Data` to a location asynchronously.
+     Not attomically by default, unless the provider enforces it.
+     
+     - Parameters:
+     - path: Path of target file.
+       - contents: Data to be written into file.
+       - overwrite: Destination file should be overwritten if file is already exists. Default is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func writeContents(path: String, contents: Data, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
+    
+    /**
+     Write the contents of the `Data` to a location asynchronously.
+     
+     - Parameters:
+       - path: Path of target file.
+       - contents: Data to be written into file.
+       - overwrite: Destination file should be overwritten if file is already exists. Default is `false`.
+       - atomically: data will be written to a temporary file before writing to final location. Default is `false`.
+       - completionHandler: If an error parameter was provided, a presentable `Error` will be returned.
+     - Returns: An `OperationHandle` to get progress or cancel progress. Doesn't work on `LocalFileProvider`.
+     */
     @discardableResult
     func writeContents(path: String, contents: Data, atomically: Bool, overwrite: Bool, completionHandler: SimpleCompletionHandler) -> OperationHandle?
     
+    /**
+     Search files inside directory using query asynchronously.
+     
+     - Note: For now only it's limited to file names. `query` parameter may take `NSPredicate` format in near future.
+     
+     - Parameters:
+       - path: location of directory to start search
+       - recursive: Searching subdirectories of path
+       - query: Simple string of file name to be search (for now).
+       - foundItemHandler: Block which is called when a file is found
+       - completionHandler: Block which will be called after finishing search. Returns an arry of `FileObject` or error if occured.
+     */
     func searchFiles(path: String, recursive: Bool, query: String, foundItemHandler: ((FileObject) -> Void)?, completionHandler: @escaping ((_ files: [FileObject], _ error: Error?) -> Void))
 }
 
@@ -185,11 +462,85 @@ extension FileProviderReadWrite {
 }
 
 public protocol FileProviderMonitor: FileProviderBasic {
+    
+    /**
+     Starts monitoring a path and its subpaths, including files and folders, for any change,
+     including copy, move/rename, content changes, etc.
+     To avoid thread congestion, `evetHandler` will be triggered with 0.2 seconds interval,
+     and has a 0.25 second delay, to ensure it's called after updates.
+     
+     - Note: this functionality is available only in `LocalFileProvider` and `CloudFileProvider`.
+     - Note: `eventHandler` is not called on main thread, for updating UI. dispatch routine to main thread.
+     - Important: `eventHandler` may be called if file is changed in recursive subpaths of registered path.
+       This may cause negative impact on performance if a root path is being monitored.
+    
+     - Parameters:
+       - path: path of directory.
+       - eventHandler: Block executed after change, on a secondary thread.
+     */
     func registerNotifcation(path: String, eventHandler: @escaping (() -> Void))
+    
+    /// Stops monitoring the path.
+    ///
+    /// - Parameter path: path of directory.
     func unregisterNotifcation(path: String)
+    
+    /// Investigate either the path is registered for change notification or not.
+    ///
+    /// - Parameter path: path of directory.
+    /// - Returns: Directory is being monitored or not.
     func isRegisteredForNotification(path: String) -> Bool
 }
 
+public protocol FileProvideUndoable: FileProviderOperations {
+    /// To initialize undo manager either call `setupUndoManager()` or set it manually.
+    ///
+    /// - Note: Only some operations (moving/renaming, copying and creating) are supported for undoing.
+    /// - Note: recording operations will occur after setting this object.
+    var undoManager: UndoManager? { get set }
+    
+    /// UndoManager supports undoing this file operation
+    func canUndo(handle: OperationHandle) -> Bool
+    /// UndoManager supports undoing this operation
+    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
+        }
+    }
+    
+    /// Initiates `self.undoManager` if equals with `nil`, and set `levelsOfUndo` to 10.
+    public func setupUndoManager() {
+        guard self.undoManager == nil else { return }
+        self.undoManager = UndoManager()
+        self.undoManager?.levelsOfUndo = 10
+    }
+}
+
 public protocol FileProvider: FileProviderBasic, FileProviderOperations, FileProviderReadWrite, NSCopying {
 }
 
@@ -199,6 +550,7 @@ extension FileProviderBasic {
         return Self.type
     }
     
+    /// path without heading and trailing slash
     public var bareCurrentPath: String {
         return currentPath.trimmingCharacters(in: pathTrimSet)
     }
@@ -207,7 +559,8 @@ 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
     }
@@ -230,12 +583,21 @@ 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!
     }
     
@@ -248,6 +610,8 @@ extension FileProviderBasic {
         return p
     }
     
+    /// Returns a file name supposed to be unique with adding numbers to end of file.
+    /// - Important: It's a synchronous method. Don't use it on matin thread.
     public func fileByUniqueName(_ filePath: String) -> String {
         let fileUrl = URL(fileURLWithPath: filePath)
         let dirPath = fileUrl.deletingLastPathComponent().path 
@@ -302,10 +666,61 @@ extension FileProviderBasic {
 }
 
 public protocol ExtendedFileProvider: FileProviderBasic {
+    /// Returuns true if thumbnail preview is supported by provider and file type accordingly.
+    ///
+    /// - Parameter path: path of file.
+    /// - Returns: A `Bool` idicates path can have thumbnail.
     func thumbnailOfFileSupported(path: String) -> Bool
+    
+    /// Returns true if provider supports fetching properties of file like dimensions, duration, etc.
+    /// Usually media or document files support these meta-infotmations.
+    ///
+    /// - Parameter path: path of file.
+    /// - Returns: A `Bool` idicates path can have properties.
     func propertiesOfFileSupported(path: String) -> Bool
+    
+    /**
+     Generates ans returns a thumbnail preview of document asynchronously. The defualt dimension of returned image is different
+     regarding provider type, usually 64x64 pixels.
+     
+     - Parameters:
+       - path: path of file.
+       - completionHandler: a block with result of preview image or error.
+         `image`: `NSImage`/`UIImage` object contains preview.
+         `error`: Error returned by system.
+    */
     func thumbnailOfFile(path: String, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void))
+    
+    /**
+     Generates ans returns a thumbnail preview of document asynchronously. The defualt dimension of returned image is different
+     regarding provider type, usually 64x64 pixels. Default value used when `dimenstion` is `nil`.
+     
+     - Note: `LocalFileInformationGenerator` variables can be set to change default behavior of
+             thumbnail and properties generator of `LocalFileProvider`.
+     
+     - Parameters:
+       - path: path of file.
+       - dimension: width and height of result preview image.
+       - completionHandler: a block with result of preview image or error.
+         `image`: `NSImage`/`UIImage` object contains preview.
+     `error`: Error returned by system.
+     */
     func thumbnailOfFile(path: String, dimension: CGSize?, completionHandler: @escaping ((_ image: ImageClass?, _ error: Error?) -> Void))
+    
+    /**
+     Fetching properties of file like dimensions, duration, etc. It's variant depending on file type.
+     Images, videos and audio files meta-information will be returned.
+     
+     - Note: `LocalFileInformationGenerator` variables can be set to change default behavior of 
+             thumbnail and properties generator of `LocalFileProvider`.
+     
+     - Parameters:
+       - path: path of file.
+       - completionHandler: a block with result of preview image or error.
+         `propertiesDictionary`: A `Dictionary` of proprty keys and values.
+         `keys`: An `Array` contains ordering of keys.
+         `error`: Error returned by system.
+     */
     func propertiesOfFile(path: String, completionHandler: @escaping ((_ propertiesDictionary: [String: Any], _ keys: [String], _ error: Error?) -> Void))
 }
 
@@ -432,13 +847,21 @@ extension ExtendedFileProvider {
     }
 }
 
+/// Operation type description of file operation, included files path in associated values.
 public enum FileOperationType: CustomStringConvertible {
+    /// Creating a file or directory in path.
     case create (path: String)
+    /// Copying a file or directory from source to destination.
     case copy   (source: String, destination: String)
+    /// Moving a file or directory from source to destination.
     case move   (source: String, destination: String)
+    /// Modifying data of a file o in path by writing new data.
     case modify (path: String)
+    /// Deleting file or directory in path.
     case remove (path: String)
+    /// Creating a symbolic link or alias to target.
     case link   (link: String, target: String)
+    /// Fetching data in file located in path.
     case fetch  (path: String)
     
     public var description: String {
@@ -453,16 +876,24 @@ public enum FileOperationType: CustomStringConvertible {
         }
     }
     
+    /// present participle of action, like 'Copying`.
     public var actionDescription: String {
         return description.trimmingCharacters(in: CharacterSet(charactersIn: "e")) + "ing"
     }
     
+    /// Path of subjecting file.
     public var source: String? {
         guard let reflect = Mirror(reflecting: self).children.first?.value else { return nil }
         let mirror = Mirror(reflecting: reflect)
         return reflect as? String ?? mirror.children.first?.value as? String
     }
     
+    /// Path of subjecting file.
+    public var path: String? {
+        return source
+    }
+    
+    /// Path of destination file.
     public var destination: String? {
         guard let reflect = Mirror(reflecting: self).children.first?.value else { return nil }
         let mirror = Mirror(reflecting: reflect)
@@ -479,11 +910,22 @@ public enum FileOperationType: CustomStringConvertible {
 
 
 public protocol OperationHandle {
+    /// Operation supposed to be done on files. Contains file paths as associated value.
     var operationType: FileOperationType { get }
+    
+    /// Bytes written/read by operation so far.
     var bytesSoFar: Int64 { get }
+    
+    /// Total bytes of operation.
     var totalBytes: Int64 { get }
+    
+    /// Operation is progress or not, Returns false if operation is done or not initiated yet.
     var inProgress: Bool { get }
+    
+    /// Progress of operation, usually equals with `bytesSoFar/totalBytes`. or NaN if not available.
     var progress: Float { get }
+    
+    /// Cancels operation while in progress, or cancels data/download/upload url session task.
     func cancel() -> Bool
 }
 
@@ -496,8 +938,15 @@ public extension OperationHandle {
 }
 
 public protocol FileProviderDelegate: class {
+    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation finished with success.
+    /// This method is called in main thread to avoids UI bugs.
     func fileproviderSucceed(_ fileProvider: FileProviderOperations, operation: FileOperationType)
+    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation finished with failure.
+    /// This method is called in main thread to avoids UI bugs.
     func fileproviderFailed(_ fileProvider: FileProviderOperations, operation: FileOperationType)
+    /// fileproviderSucceed(_:operation:) gives delegate a notification when an operation progess.
+    /// Supported by some providers, especially remote ones.
+    /// This method is called in main thread to avoids UI bugs.
     func fileproviderProgress(_ fileProvider: FileProviderOperations, operation: FileOperationType, progress: Float)
 }
 

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 +144,160 @@ 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) {
+        guard let _ = self.undoManager else { return }
+        _ = self.doOperation(box.undoOperation) { (_) 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 = sourcePath.hasPrefix("file://") ? URL(string: sourcePath)! : self.url(of: sourcePath)
+        let dest: URL?
+        
+        if let destPath = destPath {
+            dest = destPath.hasPrefix("file://") ? URL(string: destPath)! : self.url(of: destPath)
+        } else {
+            dest = nil
+        }
+        
+        if let undoManager = self.undoManager, let undoOp = self.undoOperation(for: opType) {
+            let undoBox = UndoBox(provider: self, operation: opType, undoOperation: undoOp)
+            undoManager.beginUndoGrouping()
+            undoManager.registerUndo(withTarget: self, selector: #selector(LocalFileProvider.doSimpleOperation(_:)), object: undoBox)
+            undoManager.setActionName(opType.actionDescription)
+            undoManager.endUndoGrouping()
+        }
+        
+        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()
+                }
+                
                 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)
     }
     
@@ -359,8 +307,12 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
         let url = self.url(of: path)
         
         let operationHandler: (URL) -> Void = { url in
-            let data = self.fileManager.contents(atPath: url.path)
-            completionHandler(data, nil)
+            do {
+                let data = try Data(contentsOf: url)
+                completionHandler(data, nil)
+            } catch let e {
+                completionHandler(nil, e)
+            }
         }
         
         if isCoorinating {
@@ -382,7 +334,14 @@ 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
+        }
+        
+        if offset == 0 && length < 0 {
             return self.contents(path: path, completionHandler: completionHandler)
         }
         
@@ -390,19 +349,28 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
         let url = self.url(of: path)
         
         let operationHandler: (URL) -> Void = { url in
-            guard self.fileManager.fileExists(atPath: url.path) && !url.fileIsDirectory else {
-                completionHandler(nil, self.throwError(path, code: URLError.cannotOpenFile 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.fileNoSuchFile as FoundationErrorEnum))
                 return
             }
+            
             defer {
                 handle.closeFile()
             }
+            
+            let size = LocalFileObject(fileWithURL: url)?.size ?? -1
+            guard size > offset else {
+                completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
+                return
+            }
             handle.seek(toFileOffset: UInt64(offset))
+            guard Int64(handle.offsetInFile) == offset else {
+                completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
+                return
+            }
+            
             let data = handle.readData(ofLength: length)
+            
             completionHandler(data, nil)
         }
         
@@ -426,45 +394,7 @@ 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)) {
@@ -524,11 +454,24 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
         copy.delegate = self.delegate
         copy.fileOperationDelegate = self.fileOperationDelegate
         copy.isPathRelative = self.isPathRelative
+        copy.undoManager = self.undoManager
+        copy.isCoorinating = self.isCoorinating
         return copy
     }
 }
 
 public extension LocalFileProvider {
+    /**
+     Creates a symbolic link at the specified path that points to an item at the given path.
+     This method does not traverse symbolic links contained in destURL, making it possible 
+     to create symbolic links to locations that do not yet exist. 
+     Also, if the final path component in url is a symbolic link, that link is not followed.
+    
+     - 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 {
@@ -546,6 +489,11 @@ 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 {
@@ -571,19 +519,21 @@ 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 +305,18 @@ open class LocalOperationHandle: OperationHandle {
     }
 }
 
+class UndoBox: NSObject {
+    weak var provider: FileProvideUndoable?
+    let operation: FileOperationType
+    let undoOperation: FileOperationType
+    
+    init(provider: FileProvideUndoable, operation: FileOperationType, undoOperation: FileOperationType) {
+        self.provider = provider
+        self.operation = operation
+        self.undoOperation = undoOperation
+    }
+}
+
 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 {
@@ -222,6 +240,13 @@ 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 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
+            return nil
+        }
+        
         let opType = FileOperationType.fetch(path: path)
         let url =  URL(string: escaped(path: path) + ":/content", relativeTo: driveURL)!
         var request = URLRequest(url: url)
@@ -233,12 +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()
@@ -277,7 +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()
+    }
 }
 
 
@@ -331,17 +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()
     }
@@ -349,7 +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)) {
@@ -319,6 +331,13 @@ 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 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
+            return nil
+        }
+        
         let opType = FileOperationType.fetch(path: path)
         let url = self.url(of: path)
         var request = URLRequest(url: url)
@@ -412,9 +431,10 @@ extension WebDAVFileProvider: FileProviderReadWrite {
          * A messy approach is listing a directory with an interval period and compare
          * with previous results
          */
+        NotImplemented()
     }
     fileprivate func unregisterNotifcation(path: String) {
-        
+        NotImplemented()
     }
     // TODO: implements methods for lock mechanism
 }
@@ -562,20 +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
         }
     }
 }