Use Copy instead of Move in FileSaver UI on iOS (#2981)

* Test file saver with export to service mode

* Used correct constructor with asCopy set to true

* Add temporary directory cleanup in file saving process

* Fixes disposal of temporary file on iOS

Ensures temporary directory used by the file picker is
always removed after the file selection is made, regardless
of success or failure. Also improves error handling when
a view controller cannot be retrieved.

Fixes #2460

* Fixes disposal of temporary directory on iOS

Ensures temporary directory used by the file picker is correctly removed on iOS.

Moves the directory removal to the completion handler of the view controller presentation, ensuring it's executed after the picker is dismissed.

Handles exceptions during file removal by re-throwing them after attempting to remove the temporary directory.

* Update src/CommunityToolkit.Maui.Core/Essentials/FileSaver/FileSaverImplementation.macios.cs

Co-authored-by: Copilot <[email protected]>

* Refactor temp file cleanup in FileSaver (macOS/iOS)

Move temp file removal to finally block to ensure cleanup always occurs. Remove redundant cleanup from view controller presentation callback.

* Apply suggestion from @Copilot

Co-authored-by: Copilot <[email protected]>

* Ensure resources are only created if UI is available, improve error message, ensure temp directory is deleted (not just temp file)

* Move dispose to finally

* fix naming

* fix order

* check for index

* rework File/FolderPicker. Removed IDisposable, Added IsCancelled

* Remove `ConfigureAwait(false)`, Implement CancellationToken, Implement `.WaitAsync()`

* Remove invalid `MemberNotNull`s

* Use `ExceptionDispatchInfo.Throw` to improve exception handling

* Remove `ConfigureAwait(false)`, Use `WaitAsync()`

* Remove invalid `MemberNotNull` attributes, Use `ExceptionDispatchInfo.Throw`

* Use `FolderPickerException`

---------

Co-authored-by: Vladislav Antonyuk <[email protected]>
Co-authored-by: Brandon Minnick <[email protected]>
Co-authored-by: Copilot <[email protected]>

Author: 4 people

samples/CommunityToolkit.Maui.Sample/ViewModels/Essentials/FileSaverViewModel.cs

@@ -88,9 +88,6 @@ async Task SaveFileInstance(CancellationToken cancellationToken)
 			fileSaverResult.EnsureSuccess();
 
 			await Toast.Make($"File is saved: {fileSaverResult.FilePath}").Show(cancellationToken);
-#if IOS || MACCATALYST
-			fileSaverInstance.Dispose();
-#endif
 		}
 		catch (Exception ex)
 		{

samples/CommunityToolkit.Maui.Sample/ViewModels/Essentials/FolderPickerViewModel.cs

@@ -79,9 +79,6 @@ async Task PickFolderInstance(CancellationToken cancellationToken)
 			folderPickerResult.EnsureSuccess();
 
 			await Toast.Make($"Folder picked: Name - {folderPickerResult.Folder.Name}, Path - {folderPickerResult.Folder.Path}", ToastDuration.Long).Show(cancellationToken);
-#if IOS || MACCATALYST
-			folderPickerInstance.Dispose();
-#endif
 		}
 		catch (Exception e)
 		{

src/CommunityToolkit.Maui.Core/Essentials/FileSaver/FileSaverImplementation.macios.cs

@@ -6,85 +6,93 @@ namespace CommunityToolkit.Maui.Storage;
 /// <inheritdoc cref="IFileSaver" />
 [SupportedOSPlatform("iOS14.0")]
 [SupportedOSPlatform("MacCatalyst14.0")]
-public sealed partial class FileSaverImplementation : IFileSaver, IDisposable
+public sealed partial class FileSaverImplementation : IFileSaver
 {
-	UIDocumentPickerViewController? documentPickerViewController;
-	TaskCompletionSource<string>? taskCompetedSource;
-
-	/// <inheritdoc />
-	public void Dispose()
+	Task<string> InternalSaveAsync(string fileName, Stream stream, IProgress<double>? progress, CancellationToken cancellationToken)
 	{
-		InternalDispose();
+		return InternalSaveAsync("/", fileName, stream, progress, cancellationToken);
 	}
-
-	async Task<string> InternalSaveAsync(string initialPath, string fileName, Stream stream, IProgress<double>? progress, CancellationToken cancellationToken)
+	
+	async Task<string> InternalSaveAsync(
+		string initialPath,
+		string fileName,
+		Stream stream,
+		IProgress<double>? progress,
+		CancellationToken cancellationToken)
 	{
 		cancellationToken.ThrowIfCancellationRequested();
+
+		var currentViewController = Platform.GetCurrentUIViewController()
+		                            ?? throw new FileSaveException(
+			                            "Cannot present file picker: No active view controller found. Ensure the app is active with a visible window.");
+
 		var fileManager = NSFileManager.DefaultManager;
-		var tempDirectoryPath = fileManager.GetTemporaryDirectory().Append(Guid.NewGuid().ToString(), true);
-		var isDirectoryCreated = fileManager.CreateDirectory(tempDirectoryPath, true, null, out var error);
-		if (!isDirectoryCreated)
+
+		var tempDirectoryPath = fileManager
+			.GetTemporaryDirectory()
+			.Append(Guid.NewGuid().ToString(), true);
+
+		if (!fileManager.CreateDirectory(tempDirectoryPath, true, null, out var error))
 		{
 			throw new FileSaveException(error?.LocalizedDescription ?? "Unable to create temp directory.");
 		}
 
 		var fileUrl = tempDirectoryPath.Append(fileName, false);
-		await WriteStream(stream, fileUrl.Path ?? throw new Exception("Path cannot be null."), progress, cancellationToken);
 
-		cancellationToken.ThrowIfCancellationRequested();
-		taskCompetedSource?.TrySetCanceled(CancellationToken.None);
-		var tcs = taskCompetedSource = new(cancellationToken);
+		await WriteStream(
+			stream,
+			fileUrl.Path ?? throw new FileSaveException("Path cannot be null."),
+			progress,
+			cancellationToken);
 
-		documentPickerViewController = new([fileUrl])
-		{
-			DirectoryUrl = NSUrl.FromString(initialPath)
-		};
-		documentPickerViewController.DidPickDocumentAtUrls += DocumentPickerViewControllerOnDidPickDocumentAtUrls;
-		documentPickerViewController.WasCancelled += DocumentPickerViewControllerOnWasCancelled;
+		var tcs = new TaskCompletionSource<string>(
+			TaskCreationOptions.RunContinuationsAsynchronously);
 
-		var currentViewController = Platform.GetCurrentUIViewController();
-		if (currentViewController is not null)
-		{
-			currentViewController.PresentViewController(documentPickerViewController, true, null);
-		}
-		else
-		{
-			throw new FileSaveException("Unable to get a window where to present the file saver UI.");
-		}
+		await using var registration = cancellationToken.Register(() =>
+			tcs.TrySetCanceled(cancellationToken));
 
-		return await tcs.Task.WaitAsync(cancellationToken).ConfigureAwait(false);
-	}
+		using var picker = new UIDocumentPickerViewController([fileUrl], true);
+		picker.DirectoryUrl = NSUrl.FromString(initialPath);
 
-	Task<string> InternalSaveAsync(string fileName, Stream stream, IProgress<double>? progress, CancellationToken cancellationToken)
-	{
-		return InternalSaveAsync("/", fileName, stream, progress, cancellationToken);
-	}
-
-	void DocumentPickerViewControllerOnWasCancelled(object? sender, EventArgs e)
-	{
-		taskCompetedSource?.TrySetException(new FileSaveException("Operation cancelled."));
-		InternalDispose();
-	}
+		picker.DidPickDocumentAtUrls += OnPicked;
+		picker.WasCancelled += OnCancelled;
 
-	void DocumentPickerViewControllerOnDidPickDocumentAtUrls(object? sender, UIDocumentPickedAtUrlsEventArgs e)
-	{
 		try
 		{
-			taskCompetedSource?.TrySetResult(e.Urls[0].Path ?? throw new FileSaveException("Unable to retrieve the path of the saved file."));
+			cancellationToken.ThrowIfCancellationRequested();
+			currentViewController.PresentViewController(picker, true, null);
+
+			return await tcs.Task.WaitAsync(cancellationToken);
 		}
 		finally
 		{
-			InternalDispose();
+			fileManager.Remove(tempDirectoryPath, out _);
+
+			picker.DidPickDocumentAtUrls -= OnPicked;
+			picker.WasCancelled -= OnCancelled;
+		}
+		
+		void OnPicked(object? sender, UIDocumentPickedAtUrlsEventArgs e)
+		{
+			if (e.Urls.Length is 0)
+			{
+				tcs.TrySetException(new FileSaveException("No file was selected."));
+				return;
+			}
+			
+			var path = e.Urls[0].Path;
+			if (path is null)
+			{
+				tcs.TrySetException(new FileSaveException("File path cannot be null."));
+				return;
+			}
+			
+			tcs.TrySetResult(path);
 		}
-	}
 
-	void InternalDispose()
-	{
-		if (documentPickerViewController is not null)
+		void OnCancelled(object? sender, EventArgs e)
 		{
-			documentPickerViewController.DidPickDocumentAtUrls -= DocumentPickerViewControllerOnDidPickDocumentAtUrls;
-			documentPickerViewController.WasCancelled -= DocumentPickerViewControllerOnWasCancelled;
-			documentPickerViewController.Dispose();
+			tcs.TrySetCanceled(cancellationToken);
 		}
 	}
 }

src/CommunityToolkit.Maui.Core/Essentials/FileSaver/FileSaverResult.shared.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.ExceptionServices;
 
 namespace CommunityToolkit.Maui.Storage;
 
@@ -15,6 +16,11 @@ public record FileSaverResult(string? FilePath, Exception? Exception)
 	[MemberNotNullWhen(true, nameof(FilePath))]
 	[MemberNotNullWhen(false, nameof(Exception))]
 	public bool IsSuccessful => Exception is null;
+	
+	/// <summary>
+	/// Check if the operation was cancelled.
+	/// </summary>
+	public bool IsCancelled => Exception is OperationCanceledException;
 
 	/// <summary>
 	/// Check if the operation was successful.
@@ -24,7 +30,7 @@ public void EnsureSuccess()
 	{
 		if (!IsSuccessful)
 		{
-			throw Exception;
+			ExceptionDispatchInfo.Throw(Exception);
 		}
 	}
 }

src/CommunityToolkit.Maui.Core/Essentials/FolderPicker/FolderPickerImplementation.macios.cs

@@ -8,65 +8,64 @@ namespace CommunityToolkit.Maui.Storage;
 /// <inheritdoc cref="IFolderPicker" />
 [SupportedOSPlatform("iOS14.0")]
 [SupportedOSPlatform("MacCatalyst14.0")]
-public sealed partial class FolderPickerImplementation : IFolderPicker, IDisposable
+public sealed partial class FolderPickerImplementation : IFolderPicker
 {
-	readonly UIDocumentPickerViewController documentPickerViewController = new([UTTypes.Folder])
-	{
-		AllowsMultipleSelection = false
-	};
-
-	TaskCompletionSource<Folder>? taskCompetedSource;
-
-	/// <summary>
-	/// Initializes a new instance of the <see cref="FolderPickerImplementation"/> class.
-	/// </summary>
-	public FolderPickerImplementation()
-	{
-		documentPickerViewController.DidPickDocumentAtUrls += DocumentPickerViewControllerOnDidPickDocumentAtUrls;
-		documentPickerViewController.WasCancelled += DocumentPickerViewControllerOnWasCancelled;
-	}
-
-	/// <inheritdoc />
-	public void Dispose()
+	Task<Folder> InternalPickAsync(CancellationToken cancellationToken)
 	{
-		documentPickerViewController.DidPickDocumentAtUrls -= DocumentPickerViewControllerOnDidPickDocumentAtUrls;
-		documentPickerViewController.WasCancelled -= DocumentPickerViewControllerOnWasCancelled;
-		documentPickerViewController.Dispose();
+		return InternalPickAsync("/", cancellationToken);
 	}
-
+	
 	async Task<Folder> InternalPickAsync(string initialPath, CancellationToken cancellationToken)
 	{
 		cancellationToken.ThrowIfCancellationRequested();
-		documentPickerViewController.DirectoryUrl = NSUrl.FromString(initialPath);
-		var currentViewController = Platform.GetCurrentUIViewController();
 
-		taskCompetedSource?.TrySetCanceled(CancellationToken.None);
-		var tcs = taskCompetedSource = new();
-		if (currentViewController is not null)
+		var currentViewController = Platform.GetCurrentUIViewController()
+		                            ?? throw new FolderPickerException("Unable to get a window where to present the folder picker UI.");
+
+		var tcs = new TaskCompletionSource<Folder>(
+			TaskCreationOptions.RunContinuationsAsynchronously);
+
+		await using var registration = cancellationToken.Register(() => tcs.TrySetCanceled(cancellationToken));
+
+		using var picker = new UIDocumentPickerViewController([UTTypes.Folder]);
+		picker.AllowsMultipleSelection = false;
+		picker.DirectoryUrl = NSUrl.FromString(initialPath);
+
+		picker.DidPickDocumentAtUrls += OnPicked;
+		picker.WasCancelled += OnCancelled;
+
+		try
 		{
-			currentViewController.PresentViewController(documentPickerViewController, true, null);
+			currentViewController.PresentViewController(picker, true, null);
+			return await tcs.Task.WaitAsync(cancellationToken);
 		}
-		else
+		finally
 		{
-			throw new FolderPickerException("Unable to get a window where to present the folder picker UI.");
+			picker.DidPickDocumentAtUrls -= OnPicked;
+			picker.WasCancelled -= OnCancelled;
 		}
+		
+		void OnPicked(object? sender, UIDocumentPickedAtUrlsEventArgs e)
+		{
+			if (e.Urls.Length is 0)
+			{
+				tcs.TrySetException(new FolderPickerException("No folder was selected."));
+				return;
+			}
 
-		return await tcs.Task.WaitAsync(cancellationToken).ConfigureAwait(false);
-	}
-
-	Task<Folder> InternalPickAsync(CancellationToken cancellationToken)
-	{
-		return InternalPickAsync("/", cancellationToken);
-	}
+			var path = e.Urls[0].Path;
+			if (path is null)
+			{
+				tcs.TrySetException(new FolderPickerException("File path cannot be null."));
+				return;
+			}
 
-	void DocumentPickerViewControllerOnWasCancelled(object? sender, EventArgs e)
-	{
-		taskCompetedSource?.TrySetException(new FolderPickerException("Operation cancelled."));
-	}
+			tcs.TrySetResult(new Folder(path, new DirectoryInfo(path).Name));
+		}
 
-	void DocumentPickerViewControllerOnDidPickDocumentAtUrls(object? sender, UIDocumentPickedAtUrlsEventArgs e)
-	{
-		var path = e.Urls[0].Path ?? throw new FolderPickerException("Path cannot be null.");
-		taskCompetedSource?.TrySetResult(new Folder(path, new DirectoryInfo(path).Name));
+		void OnCancelled(object? sender, EventArgs e)
+		{
+			tcs.TrySetCanceled(cancellationToken);
+		}
 	}
 }

src/CommunityToolkit.Maui.Core/Essentials/FolderPicker/FolderPickerResult.shared.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics.CodeAnalysis;
+using System.Runtime.ExceptionServices;
 using CommunityToolkit.Maui.Core.Primitives;
 
 namespace CommunityToolkit.Maui.Storage;
@@ -17,6 +18,11 @@ public record FolderPickerResult(Folder? Folder, Exception? Exception)
 	[MemberNotNullWhen(false, nameof(Exception))]
 	public bool IsSuccessful => Exception is null;
 
+	/// <summary>
+	/// Check if the operation was cancelled.
+	/// </summary>
+	public bool IsCancelled => Exception is OperationCanceledException;
+
 	/// <summary>
 	/// Check if operation was successful.
 	/// </summary>
@@ -25,7 +31,7 @@ public void EnsureSuccess()
 	{
 		if (!IsSuccessful)
 		{
-			throw Exception;
+			ExceptionDispatchInfo.Throw(Exception);
 		}
 	}
 }