feat: Support for CachedFileManager

src/Uno.UI/Resources/Strings/cs-CZ/Resources.resw

@@ -129,7 +129,10 @@
   <data name="StorageProviderLocalDisplayName" xml:space="preserve">
     <value>Tento počítač</value>
   </data>
-  <data name="StorageProviderNativeWasmDisplayName" xml:space="preserve">
+  <data name="StorageProviderWasmDownloadPickerName" xml:space="preserve">
+    <value>WASM dialog pro stažení</value>
+  </data>
+  <data name="StorageProviderWasmNativeDisplayName" xml:space="preserve">
     <value>JS File Access API</value>
   </data>
-</root>
+</root>

src/Uno.UI/Resources/Strings/en/Resources.resw

@@ -129,7 +129,7 @@
   <data name="StorageProviderLocalDisplayName" xml:space="preserve">
     <value>This PC</value>
   </data>
-  <data name="StorageProviderNativeWasmDisplayName" xml:space="preserve">
+  <data name="StorageProviderWasmNativeDisplayName" xml:space="preserve">
     <value>JS File Access API</value>
   </data>
   <data name="TEXT_CALENDARDATEPICKER_DEFAULT_PLACEHOLDER_TEXT" xml:space="preserve">
@@ -141,4 +141,7 @@
   <data name="UIA_FLIPVIEW_NEXT" xml:space="preserve">
     <value>Next</value>
   </data>
+  <data name="StorageProviderWasmDownloadPickerName" xml:space="preserve">
+    <value>WASM Download picker</value>
+  </data>
 </root>

src/Uno.UWP/Generated/3.0.0.0/Windows.Storage.Provider/FileUpdateStatus.cs

@@ -2,28 +2,28 @@
 #pragma warning disable 114 // new keyword hiding
 namespace Windows.Storage.Provider
 {
-#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
-#if __ANDROID__ || __IOS__ || NET461 || false || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+#if false
+#if false
 	[global::Uno.NotImplemented]
 	#endif
 	public enum FileUpdateStatus 
 	{
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		Incomplete,
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		Complete,
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		UserInputNeeded,
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		CurrentlyUnavailable,
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		Failed,
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false
 		CompleteAndRenamed,
 		#endif
 	}

src/Uno.UWP/Generated/3.0.0.0/Windows.Storage/CachedFileManager.cs

@@ -2,19 +2,19 @@
 #pragma warning disable 114 // new keyword hiding
 namespace Windows.Storage
 {
-#if __ANDROID__ || __IOS__ || NET461 || false || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+#if false
 	[global::Uno.NotImplemented]
 	#endif
-	public  partial class CachedFileManager 
+	public partial class CachedFileManager 
 	{
-#if __ANDROID__ || __IOS__ || NET461 || false || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+#if false
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
 		public static void DeferUpdates( global::Windows.Storage.IStorageFile file)
 		{
 			global::Windows.Foundation.Metadata.ApiInformation.TryRaiseNotImplemented("Windows.Storage.CachedFileManager", "void CachedFileManager.DeferUpdates(IStorageFile file)");
 		}
 #endif
-#if __ANDROID__ || __IOS__ || NET461 || false || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+#if false
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461","__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
 		public static global::Windows.Foundation.IAsyncOperation<global::Windows.Storage.Provider.FileUpdateStatus> CompleteUpdatesAsync( global::Windows.Storage.IStorageFile file)
 		{

src/Uno.UWP/Storage/CachedFileManager.cs

@@ -0,0 +1,41 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Windows.Foundation;
+using Windows.Storage.Provider;
+
+namespace Windows.Storage
+{
+	/// <summary>
+	/// Lets apps manage real-time updates to files.
+	/// </summary>
+	public static partial class CachedFileManager
+    {
+		/// <summary>
+		/// Lets apps defer real-time updates for a specified file.
+		/// </summary>
+		/// <param name="file">The file to defer updates for.</param>
+		/// <remarks>
+		/// In case of Uno Platform, this method currently
+		/// does not have any impact.
+		/// </remarks>
+		public static void DeferUpdates(IStorageFile file)
+		{
+		}
+
+		/// <summary>
+		/// Initiates updates for the specified file. This method contacts the app that provided the file to perform the updates.
+		/// </summary>
+		/// <param name="file">The file to update.</param>
+		/// <returns>
+		/// When this method completes, it returns a FileUpdateStatus
+		/// enum value that describes the status of the updates to the file.
+		/// </returns>
+		/// <remarks>
+		///	On most Uno Platform targets, this method immediately returns
+		///	success, as the file is already updated. In case of WASM using
+		///	the download file picker, this triggers the download file dialog.
+		/// </remarks>
+		public static IAsyncOperation<FileUpdateStatus> CompleteUpdatesAsync(IStorageFile file) =>
+			AsyncOperation.FromTask(ct => CompleteUpdatesTaskAsync(file, ct));
+	}
+}

src/Uno.UWP/Storage/CachedFileManager.other.cs

@@ -0,0 +1,14 @@
+#if !__WASM__
+using System.Threading;
+using System.Threading.Tasks;
+using Windows.Storage.Provider;
+
+namespace Windows.Storage
+{
+	public static partial class CachedFileManager
+    {
+		private static Task<FileUpdateStatus> CompleteUpdatesTaskAsync(IStorageFile file, CancellationToken token) =>
+			Task.FromResult(FileUpdateStatus.Complete);
+	}
+}
+#endif

src/Uno.UWP/Storage/CachedFileManager.wasm.cs

@@ -1,45 +1,38 @@
-using System;
 using System.IO;
 using System.Runtime.InteropServices;
-using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 using Uno.Foundation;
-using Windows.Foundation;
-using Windows.Foundation.Metadata;
+using Uno.Storage.Internal;
 using Windows.Storage.Provider;
 
 namespace Windows.Storage
 {
-	public partial class CachedFileManager
+	public static partial class CachedFileManager
 	{
-		public static void DeferUpdates(IStorageFile file)
+		private static async Task<FileUpdateStatus> CompleteUpdatesTaskAsync(IStorageFile file, CancellationToken token)
 		{
-			// The method does nothing in wasm since we don't really acces the filesystem.
-		}
-
-
-		public static IAsyncOperation<FileUpdateStatus> CompleteUpdatesAsync(IStorageFile file) => DownloadFile(file).AsAsyncOperation();
-
-		private async static Task<FileUpdateStatus> DownloadFile(IStorageFile file)
-		{
-			var stream = await file.OpenStreamForReadAsync();
-			byte[] data;
-
-			using (var reader = new BinaryReader(stream))
-			{
-				data = reader.ReadBytes((int)stream.Length);
-			}
-
-			var gch = GCHandle.Alloc(data, GCHandleType.Pinned);
-			var pinnedData = gch.AddrOfPinnedObject();
-
-			try
-			{
-				WebAssemblyRuntime.InvokeJS($"Windows.Storage.Pickers.FileSavePicker.SaveAs('{file.Name}', {pinnedData}, {data.Length})");
-			}
-			finally
+			if (file is StorageFile storageFile && storageFile.Provider == StorageProviders.WasmDownloadPicker)
 			{
-				gch.Free();
+				var stream = await file.OpenStreamForReadAsync();
+				byte[] data;
+
+				using (var reader = new BinaryReader(stream))
+				{
+					data = reader.ReadBytes((int)stream.Length);
+				}
+
+				var gch = GCHandle.Alloc(data, GCHandleType.Pinned);
+				var pinnedData = gch.AddrOfPinnedObject();
+
+				try
+				{
+					WebAssemblyRuntime.InvokeJS($"Windows.Storage.Pickers.FileSavePicker.SaveAs('{file.Name}', {pinnedData}, {data.Length})");
+				}
+				finally
+				{
+					gch.Free();
+				}
 			}
 
 			return FileUpdateStatus.Complete;

src/Uno.UWP/Storage/Internal/StorageProviders.cs

@@ -7,7 +7,9 @@ internal static class StorageProviders
 		public static StorageProvider Local { get; } = new StorageProvider("computer", "StorageProviderLocalDisplayName");
 
 #if __WASM__
-		public static StorageProvider NativeWasm { get; } = new StorageProvider("jsfileaccessapi", "StorageProviderNativeWasmDisplayName");
+		public static StorageProvider WasmDownloadPicker { get; } = new StorageProvider("wasmdownloadpicker", "StorageProviderWasmDownloadPickerName");
+
+		public static StorageProvider WasmNative { get; } = new StorageProvider("jsfileaccessapi", "StorageProviderWasmNativeDisplayName");
 #endif
 
 #if __ANDROID__

src/Uno.UWP/Storage/Pickers/FileSavePicker.wasm.cs

@@ -98,6 +98,7 @@ private NativeFilePickerAcceptType[] BuildFileTypesMap()
 				// The mime type is chosen by the extension, and we cannot reliably send multiple mime type in the browser
 				var fileName = SuggestedFileName + extension;
 				SuggestedSaveFile = await temporaryFolder.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);
+				SuggestedSaveFile.ProviderOverride = StorageProviders.WasmDownloadPicker;
 			}
 			return SuggestedSaveFile;
 		}

src/Uno.UWP/Storage/Provider/FileUpdateStatus.cs

@@ -0,0 +1,44 @@
+namespace Windows.Storage.Provider
+{
+	/// <summary>
+	/// Describes the status of a file update request.
+	/// </summary>
+	public enum FileUpdateStatus
+	{
+		/// <summary>
+		/// The file update was not fully completed and should be retried.
+		/// </summary>
+		Incomplete,
+
+		/// <summary>
+		/// The file update was completed successfully.
+		/// </summary>
+		Complete,
+
+		/// <summary>
+		/// User input (like credentials) is needed to update the file.
+		/// </summary>
+		UserInputNeeded,
+
+		/// <summary>
+		/// The remote version of the file was not updated because the storage location
+		/// wasn't available. The file remains valid and subsequent updates
+		/// to the file may succeed.
+		/// </summary>
+		CurrentlyUnavailable,
+
+		/// <summary>
+		/// The file is now invalid and can't be updated now or in the future. For example,
+		/// this could occur if the remote version of the file was deleted.
+		/// </summary>
+		Failed,
+
+		/// <summary>
+		/// The file update was completed successfully and the file has been renamed.
+		/// For example, this could occur if the user chose to save their changes under
+		/// a different file name because of conflicting changes made to the remote
+		/// version of the file.
+		/// </summary>
+		CompleteAndRenamed,
+	}
+}

src/Uno.UWP/Storage/StorageFile.cs

@@ -41,7 +41,12 @@ private StorageFile(ImplementationBase implementation)
 
 		internal ImplementationBase Implementation { get; }
 
-		public StorageProvider Provider => Implementation.Provider;
+		/// <summary>
+		/// Allows internal Uno implementations to override the storage provider.
+		/// </summary>
+		internal StorageProvider? ProviderOverride { get; set; }
+
+		public StorageProvider Provider => ProviderOverride ?? Implementation.Provider;
 
 		public string Path => Implementation.Path;
 

src/Uno.UWP/Storage/StorageFile.native.wasm.cs

@@ -39,7 +39,7 @@ public NativeStorageFile(NativeStorageItemInfo nativeStorageItem, StorageFolder?
 				_parent = parent;
 			}
 
-			public override StorageProvider Provider => StorageProviders.NativeWasm;
+			public override StorageProvider Provider => StorageProviders.WasmNative;
 
 			public override string Name => _fileName;
 

src/Uno.UWP/Storage/StorageFolder.native.wasm.cs

@@ -41,7 +41,7 @@ public NativeStorageFolder(NativeStorageItemInfo info, StorageFolder? parent)
 				_parent = parent;
 			}
 
-			public override StorageProvider Provider => StorageProviders.NativeWasm;
+			public override StorageProvider Provider => StorageProviders.WasmNative;
 
 			public static async Task<StorageFolder?> GetPrivateRootAsync()
 			{