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   - brew outdated carthage || brew upgrade carthage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+  - brew outdated carthage || brew upgrade carthage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      = "0.12.1"
+  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 = 0.12.1;
+				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 = 0.12.1;
+				BUNDLE_VERSION_STRING = 0.12.4;
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_EMPTY_BODY = YES;

README.md

@@ -31,15 +31,15 @@ Local and WebDAV providers are fully tested and can be used in production enviro
 - [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 REST API.
+- [x] **DropboxFileProvider** A wrapper around Dropbox Web API.
     * For now it has limitation in uploading files up to 150MB.
 - [x] **OneDriveFileProvider** A wrapper around OneDrive REST API, works with `onedrive.com` and compatible (business) servers.
     * For now it has limitation in uploading files up to 100MB.
 - [ ] **GoogleFileProvider** A wrapper around Goodle Drive REST API.
 - [ ] **AmazonS3FileProvider** Amazon storage backend. Used by many sites.
 - [ ] **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
+    * 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.
 
 ## Requirements
@@ -69,7 +69,7 @@ github "amosavian/FileProvider"
 Or to use in Swift Package Manager add this line in `Dependencies`:
 
 ```swift
-.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0, minorVersion: 8)
+.Package(url: "https://github.com/amosavian/FileProvider.git", majorVersion: 0, minorVersion: 12)
 ```
 
 ### Manually
@@ -329,13 +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.
 

Sources/CloudFileProvider.swift

@@ -11,7 +11,8 @@ import Foundation
 open class CloudFileProvider: LocalFileProvider {
     open override class 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
@@ -24,6 +25,9 @@ open class CloudFileProvider: LocalFileProvider {
     /// The fully-qualified container identifier for an iCloud container directory.
     open fileprivate(set) var 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.
@@ -31,10 +35,11 @@ open class CloudFileProvider: LocalFileProvider {
      - 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.
+         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?) {
+    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
@@ -43,7 +48,14 @@ 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
         
@@ -57,12 +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 {
@@ -91,9 +105,14 @@ open class CloudFileProvider: LocalFileProvider {
                     }
                 }
                 
+                query.stop()
                 completionHandler(contents, nil)
             })
-            query.start()
+            DispatchQueue.main.async {
+                if !query.start() {
+                    completionHandler([], self.throwError(path, code: CocoaError.fileReadNoPermission))
+                }
+            }
         }
     }
     
@@ -107,7 +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 {
@@ -130,7 +149,11 @@ open class CloudFileProvider: LocalFileProvider {
                     completionHandler(nil, noFileError)
                 }
             })
-            query.start()
+            DispatchQueue.main.async {
+                if !query.start() {
+                    completionHandler(nil, self.throwError(path, code: CocoaError.fileReadNoPermission))
+                }
+            }
         }
     }
     
@@ -239,7 +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
             
@@ -302,18 +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
             
@@ -324,24 +351,25 @@ 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
     }
     
     open override func copy(with zone: NSZone? = nil) -> Any {
@@ -401,6 +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
@@ -458,11 +518,12 @@ open class CloudOperationHandle: OperationHandle {
     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 {
@@ -479,8 +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

@@ -133,8 +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)
@@ -244,7 +242,10 @@ extension DropboxFileProvider: FileProviderOperations {
 
 extension DropboxFileProvider: FileProviderReadWrite {
     public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -305,12 +306,12 @@ extension DropboxFileProvider: FileProviderReadWrite {
         NotImplemented()
     }
     
-    // TODO: Implement /copy_reference, /get_account & /get_current_account
+    // TODO: Implement /get_account & /get_current_account
 }
 
 extension DropboxFileProvider {
     /// *DEPRECATED:* Use `publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?))` function instead.
-    @available(*, deprecated, message: "Use publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
+    @available(*, deprecated, renamed: "publicLink(to:completionHandler:)", message: "Use publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?)) function instead.")
     open func temporaryLink(to path: String, completionHandler: @escaping ((_ link: URL?, _ attribute: DropboxFileObject?, _ error: Error?) -> Void)) {
         self.publicLink(to: path) { (url, file, _, error) in
             completionHandler(url, file, error)
@@ -318,7 +319,7 @@ extension DropboxFileProvider {
     }
     
     /// *DEPRECATED:* Use `publicLink(to:, completionHandler: (URL?, DropboxFileObject?, Date?,  Error?))` function instead.
-    @available(*, deprecated, message: "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)

Sources/DropboxHelper.swift

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

Sources/ExtendedLocalFileProvider.swift

@@ -123,7 +123,6 @@ extension LocalFileProvider: ExtendedFileProvider {
             
             completionHandler(dic, keys, nil)
         }
-        
     }
 }
 
@@ -189,6 +188,16 @@ public struct LocalFileInformationGenerator {
     }
     
     static public var imageProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         func simplify(_ top:Int64, _ bottom:Int64) -> (newTop:Int, newBottom:Int) {
             var x = top
             var y = bottom
@@ -203,79 +212,57 @@ public struct LocalFileInformationGenerator {
             return(Int(newTopVal), Int(newBottomVal))
         }
         
-        var dic = [String: Any]()
-        var keys = [String]()
         guard let cgDataRef = CGImageSourceCreateWithURL(fileURL as CFURL, nil), let cfImageDict = CGImageSourceCopyPropertiesAtIndex(cgDataRef, 0, nil) else {
             return (dic, keys)
         }
         let imageDict = cfImageDict as NSDictionary
-        let tiffDict = imageDict[kCGImagePropertyTIFFDictionary as String] as? [String : AnyObject] ?? [:]
-        let exifDict = imageDict[kCGImagePropertyExifDictionary as String] as? [String : AnyObject] ?? [:]
-        if let pixelWidth: AnyObject = imageDict.object(forKey: kCGImagePropertyPixelWidth) as? NSNumber, let pixelHeight: AnyObject = imageDict.object(forKey: kCGImagePropertyPixelHeight) as? NSNumber {
-            keys.append("Dimensions")
-            dic["Dimensions"] = "\(pixelWidth)x\(pixelHeight)"
-        }
-        if let dpi = imageDict[kCGImagePropertyDPIWidth as String] {
-            keys.append("DPI")
-            dic["DPI"] = dpi
-        }
-        if let devicemake = tiffDict[kCGImagePropertyTIFFMake as String] {
-            keys.append("Device make")
-            dic["Device make"] = devicemake
-        }
-        if let devicemodel = tiffDict[kCGImagePropertyTIFFModel as String] {
-            keys.append("Device model")
-            dic["Device model"] = devicemodel
-        }
-        if let lensmodel = exifDict[kCGImagePropertyExifLensModel as String] {
-            keys.append("Lens model")
-            dic["Lens model"] = lensmodel
-        }
-        if let artist = tiffDict[kCGImagePropertyTIFFArtist as String] as? String , !artist.isEmpty {
-            keys.append("Artist")
-            dic["Artist"] = artist
+        let tiffDict = imageDict[kCGImagePropertyTIFFDictionary as String] as? NSDictionary ?? [:]
+        let exifDict = imageDict[kCGImagePropertyExifDictionary as String] as? NSDictionary ?? [:]
+        if let pixelWidth = imageDict.object(forKey: kCGImagePropertyPixelWidth) as? NSNumber, let pixelHeight = imageDict.object(forKey: kCGImagePropertyPixelHeight) as? NSNumber {
+            add(key: "Dimensions", value: "\(pixelWidth)x\(pixelHeight)")
         }
+        
+        add(key: "DPI", value: imageDict[kCGImagePropertyDPIWidth as String])
+        add(key: "Device make", value: tiffDict[kCGImagePropertyTIFFMake as String])
+        add(key: "Device model", value: tiffDict[kCGImagePropertyTIFFModel as String])
+        add(key: "Lens model", value: exifDict[kCGImagePropertyExifLensModel as String])
+        add(key: "Artist", value: tiffDict[kCGImagePropertyTIFFArtist as String] as? String)
         if let cr = tiffDict[kCGImagePropertyTIFFCopyright as String] as? String , !cr.isEmpty {
-            keys.append("Copyright")
-            dic["Copyright"] = cr
+            add(key: "Copyright", value: cr)
+
         }
         if let date = tiffDict[kCGImagePropertyTIFFDateTime as String] as? String , !date.isEmpty {
-            keys.append("Date taken")
-            dic["Date taken"] = date
+            add(key: "Date taken", value: date)
         }
-        if let latitude = tiffDict[kCGImagePropertyGPSLatitude as String]?.doubleValue, let longitude = tiffDict[kCGImagePropertyGPSLongitude as String]?.doubleValue {
-            keys.append("Location")
-            dic["Location"] = "\(latitude), \(longitude)"
+        if let latitude = tiffDict[kCGImagePropertyGPSLatitude as String] as? NSNumber, let longitude = tiffDict[kCGImagePropertyGPSLongitude as String] as? NSNumber {
+            add(key: "Location", value: "\(latitude), \(longitude)")
         }
-        if let colorspace = imageDict[kCGImagePropertyColorModel as String] {
-            keys.append("Color space")
-            dic["Color space"] = colorspace
-        }
-        if let focallen = exifDict[kCGImagePropertyExifFocalLength as String] {
-            keys.append("Focal length")
-            dic["Focal length"] = focallen
-        }
-        if let fnum = exifDict[kCGImagePropertyExifFNumber as String] {
-            keys.append("F number")
-            dic["F number"] = fnum
-        }
-        if let expprog = exifDict[kCGImagePropertyExifExposureProgram as String] {
-            keys.append("Exposure program")
-            dic["Exposure program"] = expprog
-        }
-        if let exp = exifDict[kCGImagePropertyExifExposureTime as String]?.doubleValue {
-            let expfrac = simplify(Int64(exp * 10_000_000_000_000), 10_000_000_000_000)
-            keys.append("Exposure time")
-            dic["Exposure time"] = "\(expfrac.newTop)/\(expfrac.newBottom)"
+        add(key: "Color space", value: imageDict[kCGImagePropertyColorModel as String])
+        add(key: "Focal length", value: exifDict[kCGImagePropertyExifFocalLength as String])
+        add(key: "F number", value: exifDict[kCGImagePropertyExifFNumber as String])
+        add(key: "Exposure program", value: exifDict[kCGImagePropertyExifExposureProgram as String])
+        
+        if let exp = exifDict[kCGImagePropertyExifExposureTime as String] as? NSNumber {
+            let expfrac = simplify(Int64(exp.doubleValue * 10_000_000_000_000), 10_000_000_000_000)
+            add(key: "Exposure time", value: "\(expfrac.newTop)/\(expfrac.newBottom)")
         }
         if let iso = exifDict[kCGImagePropertyExifISOSpeedRatings as String] as? NSArray , iso.count > 0 {
-            keys.append("ISO speed")
-            dic["ISO speed"] = iso[0]
+            add(key: "ISO speed", value: iso[0])
         }
         return (dic, keys)
     }
     
     static var audioProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         func makeDescription(_ key: String?) -> String? {
             guard let key = key else {
                 return nil
@@ -287,8 +274,6 @@ public struct LocalFileInformationGenerator {
             return newKey.capitalized
         }
         
-        var dic = [String: Any]()
-        var keys = [String]()
         if FileManager.default.fileExists(atPath: fileURL.path) {
             let playerItem = AVPlayerItem(url: fileURL)
             let metadataList = playerItem.asset.commonMetadata
@@ -301,12 +286,8 @@ public struct LocalFileInformationGenerator {
                 }
             }
             if let ap = try? AVAudioPlayer(contentsOf: fileURL) {
-                keys.append("Duration")
-                dic["Duration"] = LocalFileProvider.formatshort(interval: ap.duration)
-                if let bitRate = ap.settings[AVSampleRateKey] as? Int {
-                    keys.append("Bitrate")
-                    dic["Bitrate"] = bitRate
-                }
+                add(key: "Duration", value: LocalFileProvider.formatshort(interval: ap.duration))
+                add(key: "Bitrate", value: ap.settings[AVSampleRateKey] as? Int)
             }
         }
         return (dic, keys)
@@ -315,6 +296,14 @@ public struct LocalFileInformationGenerator {
     static public var videoProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
         var dic = [String: Any]()
         var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         if let audioprops = LocalFileInformationGenerator.audioProperties?(fileURL) {
             dic = audioprops.prop
             keys = audioprops.keys
@@ -329,17 +318,14 @@ public struct LocalFileInformationGenerator {
             var bitrate: Float = 0
             let width = Int(videoTracks[0].naturalSize.width)
             let height = Int(videoTracks[0].naturalSize.height)
-            keys.append("Dimensions")
-            dic["Dimensions"] = "\(width)x\(height)"
+            add(key: "Dimensions", value: "\(width)x\(height)")
             var duration: Int64 = 0
             for track in videoTracks {
                 duration += track.timeRange.duration.timescale > 0 ? track.timeRange.duration.value / Int64(track.timeRange.duration.timescale) : 0
                 bitrate += track.estimatedDataRate
             }
-            keys.append("Duration")
-            dic["Duration"] = LocalFileProvider.formatshort(interval: TimeInterval(duration))
-            keys.append("Video Bitrate")
-            dic["Video Bitrate"] = "\(Int(ceil(bitrate / 1000))) kbps"
+            add(key: "Duration", value: LocalFileProvider.formatshort(interval: TimeInterval(duration)))
+            add(key: "Video Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
         }
         let audioTracks = asset.tracks(withMediaType: AVMediaTypeAudio)
         // dic["Audio channels"] = audioTracks.count
@@ -347,12 +333,21 @@ public struct LocalFileInformationGenerator {
         for track in audioTracks {
             bitrate += track.estimatedDataRate
         }
-        keys.append("Audio Bitrate")
-        dic["Audio Bitrate"] = "\(Int(ceil(bitrate / 1000))) kbps"
+        add(key: "Audio Bitrate", value: "\(Int(ceil(bitrate / 1000))) kbps")
         return (dic, keys)
     }
     
     static public var pdfProperties: ((_ fileURL: URL) -> (prop: [String: Any], keys: [String]))? = { fileURL in
+        var dic = [String: Any]()
+        var keys = [String]()
+        
+        func add(key: String, value: Any?) {
+            if let value = value {
+                keys.append(key)
+                dic[key] = value
+            }
+        }
+        
         func getKey(_ key: String, from dict: CGPDFDictionaryRef) -> String? {
             var cfValue: CGPDFStringRef? = nil
             if (CGPDFDictionaryGetString(dict, key, &cfValue)), let value = CGPDFStringCopyTextString(cfValue!) {
@@ -378,56 +373,40 @@ public struct LocalFileInformationGenerator {
             return nil
         }
         
-        var dic = [String: Any]()
-        var keys = [String]()
         if let data = try? Data(contentsOf: fileURL), let provider = CGDataProvider(data: data as CFData), let reference = CGPDFDocument(provider), let dict = reference.info {
             if let title = getKey("Title", from: dict), !title.isEmpty {
-                keys.append("Title")
-                dic["Title"] = title
+                add(key: "Title", value: title)
             }
             if let author = getKey("Author", from: dict), !author.isEmpty {
-                keys.append("Author")
-                dic["Author"] = author
+                add(key: "Author", value: author)
             }
             if let subject = getKey("Subject", from: dict), !subject.isEmpty {
-                keys.append("Subject")
-                dic["Subject"] = subject
+                add(key: "Subject", value: subject)
             }
             var majorVersion: Int32 = 0
             var minorVersion: Int32 = 0
             reference.getVersion(majorVersion: &majorVersion, minorVersion: &minorVersion)
             if majorVersion > 0 {
-                keys.append("Version")
-                dic["Version"] = String(majorVersion) + "." + String(minorVersion)
-            }
-            if reference.numberOfPages > 0 {
-                keys.append("Pages")
-                dic["Pages"] = reference.numberOfPages
+                add(key: "Version", value:  String(majorVersion) + "." + String(minorVersion))
             }
+            add(key: "Pages", value: reference.numberOfPages)
             
             if reference.numberOfPages > 0, let pageRef = reference.page(at: 1) {
                 let size = pageRef.getBoxRect(CGPDFBox.mediaBox).size
-                keys.append("Resolution")
-                dic["Resolution"] = "\(Int(size.width))x\(Int(size.height))"
+                add(key: "Resolution", value: "\(Int(size.width))x\(Int(size.height))")
             }
             if let creator = getKey("Creator", from: dict), !creator.isEmpty {
-                keys.append("Content creator")
-                dic["Content creator"] = creator
+                add(key: "Content creator", value: creator)
             }
-            if let creationDateString = getKey("CreationDate", from: dict), let creationDate = convertDate(creationDateString) {
-                keys.append("Creation date")
-                dic["Creation date"] = creationDate
+            if let creationDateString = getKey("CreationDate", from: dict) {
+                add(key: "Creation date", value: convertDate(creationDateString))
             }
-            if let modifiedDateString = getKey("ModDate", from: dict), let modDate = convertDate(modifiedDateString) {
-                keys.append("Modified date")
-                dic["Modified date"] = modDate
+            if let modifiedDateString = getKey("ModDate", from: dict) {
+                add(key: "Modified date", value: convertDate(modifiedDateString))
             }
-            keys.append("Security")
-            dic["Security"] = reference.isEncrypted ? "Present" : "None"
-            keys.append("Allows printing")
-            dic["Allows printing"] = reference.allowsPrinting ? "Yes" : "No"
-            keys.append("Allows copying")
-            dic["Allows copying"] = reference.allowsCopying ? "Yes" : "No"
+            add(key: "Security", value: reference.isEncrypted ? "Present" : "None")
+            add(key: "Allows printing", value: reference.allowsPrinting ? "Yes" : "No")
+            add(key: "Allows copying", value: reference.allowsCopying ? "Yes" : "No")
         }
         return (dic, keys)
     }

Sources/FileObject.swift

@@ -11,21 +11,21 @@ import Foundation
 /// Containts path and attributes of a file or resource.
 open class FileObject {
     /// A `Dictionary` contains file information,  using `URLResourceKey` keys.
-    open internal(set) var allValues: [String: Any]
+    open internal(set) var allValues: [URLResourceKey: Any]
     
-    internal init(allValues: [String: Any]) {
+    internal init(allValues: [URLResourceKey: Any]) {
         self.allValues = allValues
     }
     
     internal init(url: URL, name: String, path: String) {
-        self.allValues = [String: Any]()
+        self.allValues = [URLResourceKey: Any]()
         self.url = url
         self.name = name
         self.path = path
     }
     
     /// url to access the resource, not supported by Dropbox provider
-    @available(*, deprecated, message: "Use url.absoluteURL instead.")
+    @available(*, deprecated, renamed: "url", message: "Use url.absoluteURL instead.")
     open var absoluteURL: URL? {
         return url?.absoluteURL
     }
@@ -34,75 +34,75 @@ open class FileObject {
     /// 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
         }
     }
     
-    /// **DEPRECATED:** Use `type` property instead.
-    @available(*, deprecated, message: "Use 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
     }
@@ -111,20 +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
         }
     }
     
@@ -296,6 +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

@@ -492,6 +492,55 @@ public protocol FileProviderMonitor: FileProviderBasic {
     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 {
 }
 
@@ -510,8 +559,8 @@ extension FileProviderBasic {
         return path.trimmingCharacters(in: pathTrimSet).addingPercentEncoding(withAllowedCharacters: .urlPathAllowed)!
     }
     
-    /// **DEPRECATED:** Use `url(of:).absoluteURL` instead.
-    @available(*, deprecated, message: "Use 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
     }
@@ -534,11 +583,20 @@ 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!
         }
         
+        // resolve url string against baseurl
         guard let baseURL = self.baseURL?.standardizedFileURL else { return url.absoluteString }
         return url.standardizedFileURL.absoluteString.replacingOccurrences(of: baseURL.absoluteString, with: "/").removingPercentEncoding!
     }

Sources/LocalFileProvider.swift

@@ -8,7 +8,7 @@
 
 import Foundation
 
-open class LocalFileProvider: FileProvider, FileProviderMonitor {
+open class LocalFileProvider: FileProvider, FileProviderMonitor, FileProvideUndoable {
     open class var type: String { return "Local" }
     open var isPathRelative: Bool
     open fileprivate(set) var baseURL: URL?
@@ -22,6 +22,8 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     open private(set) var opFileManager = FileManager()
     fileprivate var fileProviderManagerDelegate: LocalFileProviderManagerDelegate? = nil
     
+    open var undoManager: UndoManager? = nil
+    
     /**
      Forces file operations to use `NSFileCoordinating`, should be set `true` if:
      - Files are on ubiquity (iCloud) container.
@@ -112,7 +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)
@@ -125,9 +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)
     }
     
@@ -142,245 +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)
     }
     
@@ -417,7 +334,10 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
     
     @discardableResult
     open func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -429,12 +349,8 @@ 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.fileDoesNotExist 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
             }
             
@@ -442,17 +358,18 @@ open class LocalFileProvider: FileProvider, FileProviderMonitor {
                 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.fileReadUnknown as FoundationErrorEnum))
+                completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
                 return
             }
             
             let data = handle.readData(ofLength: length)
-            guard length > 0 && data.count == length else {
-                completionHandler(nil, self.throwError(path, code: CocoaError.fileReadTooLarge as FoundationErrorEnum))
-                return
-            }
             
             completionHandler(data, nil)
         }
@@ -477,45 +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)) {
@@ -575,6 +454,8 @@ 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
     }
 }
@@ -638,19 +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

@@ -240,7 +240,10 @@ extension OneDriveFileProvider: FileProviderOperations {
 
 extension OneDriveFileProvider: FileProviderReadWrite {
     public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         

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/WebDAVFileProvider.swift

@@ -331,7 +331,10 @@ extension WebDAVFileProvider: FileProviderOperations {
 extension WebDAVFileProvider: FileProviderReadWrite {
     @discardableResult
     public func contents(path: String, offset: Int64, length: Int, completionHandler: @escaping ((_ contents: Data?, _ error: Error?) -> Void)) -> OperationHandle? {
-        if length == 0 {
+        if length == 0 || offset < 0 {
+            dispatch_queue.async {
+                completionHandler(Data(), nil)
+            }
             return nil
         }
         
@@ -579,20 +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
         }
     }
 }