Fix: Fixed issue where loading thumbnails sometimes took very long time

src/Files.App/Data/Models/ItemViewModel.cs

@@ -30,6 +30,7 @@ public sealed class ItemViewModel : ObservableObject, IDisposable
 		private readonly SemaphoreSlim enumFolderSemaphore;
 		private readonly SemaphoreSlim getFileOrFolderSemaphore;
 		private readonly SemaphoreSlim bulkOperationSemaphore;
+		private readonly SemaphoreSlim loadThumbnailSemaphore;
 		private readonly ConcurrentQueue<(uint Action, string FileName)> operationQueue;
 		private readonly ConcurrentQueue<uint> gitChangesQueue;
 		private readonly ConcurrentDictionary<string, bool> itemLoadQueue;
@@ -485,6 +486,7 @@ public ItemViewModel(LayoutPreferencesManager folderSettingsViewModel)
 			enumFolderSemaphore = new SemaphoreSlim(1, 1);
 			getFileOrFolderSemaphore = new SemaphoreSlim(50);
 			bulkOperationSemaphore = new SemaphoreSlim(1, 1);
+			loadThumbnailSemaphore = new SemaphoreSlim(1, 1);
 			dispatcherQueue = DispatcherQueue.GetForCurrentThread();
 
 			UserSettingsService.OnSettingChangedEvent += UserSettingsService_OnSettingChangedEvent;
@@ -914,18 +916,51 @@ private async Task<BitmapImage> GetShieldIcon()
 			return shieldIcon;
 		}
 
-		private async Task LoadThumbnailAsync(ListedItem item)
+		private async Task LoadThumbnailAsync(ListedItem item, CancellationToken cancellationToken)
 		{
-			// Cancel if thumbnails aren't enabled
+			var loadNonCachedThumbnail = false;
 			var thumbnailSize = folderSettings.GetRoundedIconSize();
 			var returnIconOnly = UserSettingsService.FoldersSettingsService.ShowThumbnails == false || thumbnailSize < 48;
 
-			// Get thumbnail
-			var result = await FileThumbnailHelper.GetIconAsync(
-					item.ItemPath,
-					thumbnailSize,
-					item.IsFolder,
-					returnIconOnly ? IconOptions.ReturnIconOnly : IconOptions.None);
+			byte[]? result = null;
+			if (item.IsFolder)
+			{
+				if (!returnIconOnly)
+				{
+					// Get cached thumbnail
+					result = await FileThumbnailHelper.GetIconAsync(
+							item.ItemPath,
+							thumbnailSize,
+							item.IsFolder,
+							IconOptions.ReturnThumbnailOnly | IconOptions.ReturnOnlyIfCached);
+
+					cancellationToken.ThrowIfCancellationRequested();
+					loadNonCachedThumbnail = true;
+				}
+
+				if (result is null)
+				{
+					// Get icon
+					result = await FileThumbnailHelper.GetIconAsync(
+							item.ItemPath,
+							thumbnailSize,
+							item.IsFolder,
+							IconOptions.ReturnIconOnly);
+
+					cancellationToken.ThrowIfCancellationRequested();
+				}
+			}
+			else
+			{
+				// Get icon or thumbnail
+				result = await FileThumbnailHelper.GetIconAsync(
+						item.ItemPath,
+						thumbnailSize,
+						item.IsFolder,
+						returnIconOnly ? IconOptions.ReturnIconOnly : IconOptions.None);
+
+				cancellationToken.ThrowIfCancellationRequested();
+			}
 
 			if (result is not null)
 			{
@@ -936,17 +971,57 @@ await dispatcherQueue.EnqueueOrInvokeAsync(async () =>
 					if (image is not null)
 						item.FileImage = image;
 				}, Microsoft.UI.Dispatching.DispatcherQueuePriority.Low);
+
+				cancellationToken.ThrowIfCancellationRequested();
 			}
 
 			// Get icon overlay
 			var iconOverlay = await FileThumbnailHelper.GetIconOverlayAsync(item.ItemPath, true);
+
+			cancellationToken.ThrowIfCancellationRequested();
+
 			if (iconOverlay is not null)
 			{
 				await dispatcherQueue.EnqueueOrInvokeAsync(async () =>
 				{
 					item.IconOverlay = await iconOverlay.ToBitmapAsync();
 					item.ShieldIcon = await GetShieldIcon();
 				}, Microsoft.UI.Dispatching.DispatcherQueuePriority.Low);
+
+				cancellationToken.ThrowIfCancellationRequested();
+			}
+
+			if (loadNonCachedThumbnail)
+			{
+				// Get non-cached thumbnail asynchronously
+				_ = Task.Run(async () => {
+					await loadThumbnailSemaphore.WaitAsync(cancellationToken);
+					try
+					{
+						result = await FileThumbnailHelper.GetIconAsync(
+								item.ItemPath,
+								thumbnailSize,
+								item.IsFolder,
+								IconOptions.ReturnThumbnailOnly);
+					}
+					finally
+					{
+						loadThumbnailSemaphore.Release();
+					}
+
+					cancellationToken.ThrowIfCancellationRequested();
+
+					if (result is not null)
+					{
+						await dispatcherQueue.EnqueueOrInvokeAsync(async () =>
+						{
+							// Assign FileImage property
+							var image = await result.ToBitmapAsync();
+							if (image is not null)
+								item.FileImage = image;
+						}, Microsoft.UI.Dispatching.DispatcherQueuePriority.Low);
+					}
+				}, cancellationToken);
 			}
 		}
 
@@ -990,7 +1065,7 @@ public async Task LoadExtendedItemPropertiesAsync(ListedItem item)
 					}
 
 					cts.Token.ThrowIfCancellationRequested();
-					await LoadThumbnailAsync(item);
+					await LoadThumbnailAsync(item, cts.Token);
 
 					cts.Token.ThrowIfCancellationRequested();
 					if (item.IsLibrary || item.PrimaryItemAttribute == StorageItemTypes.File || item.IsArchive)
@@ -1104,7 +1179,8 @@ await dispatcherQueue.EnqueueOrInvokeAsync(() =>
 						{
 							_ = Task.Run(async () => {
 								await Task.Delay(500);
-								await LoadThumbnailAsync(item);
+								cts.Token.ThrowIfCancellationRequested();
+								await LoadThumbnailAsync(item, cts.Token);
 							});
 						}
 					}

src/Files.App/Files.App.csproj

@@ -80,7 +80,7 @@
         <PackageReference Include="LiveChartsCore.SkiaSharpView.WinUI" Version="2.0.0-rc1.2" />
         <PackageReference Include="Microsoft.AppCenter.Analytics" Version="5.0.3" />
         <PackageReference Include="Microsoft.AppCenter.Crashes" Version="5.0.3" />
-        <PackageReference Include="Microsoft.Data.Sqlite.Core" Version="8.0.2" />
+        <PackageReference Include="Microsoft.Data.Sqlite.Core" Version="8.0.3" />
         <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
         <PackageReference Include="Microsoft.Extensions.Hosting" Version="8.0.0" />
         <PackageReference Include="Microsoft.Extensions.Logging" Version="8.0.0" />

src/Files.App/Helpers/Win32/Win32Helper.Storage.cs

@@ -281,13 +281,13 @@ public static string ExtractStringFromDLL(string file, int number)
 		/// <param name="path"></param>
 		/// <param name="size"></param>
 		/// <param name="isFolder"></param>
-		/// <param name="returnIconOnly"></param>
+		/// <param name="iconOptions"></param>
 		/// <returns></returns>
 		public static byte[]? GetIcon(
 			string path,
 			int size,
 			bool isFolder,
-			bool returnIconOnly)
+			IconOptions iconOptions)
 		{
 			byte[]? iconData = null;
 
@@ -301,9 +301,15 @@ public static string ExtractStringFromDLL(string file, int number)
 				{
 					var flags = Shell32.SIIGBF.SIIGBF_BIGGERSIZEOK;
 
-					if (returnIconOnly)
+					if (iconOptions.HasFlag(IconOptions.ReturnIconOnly))
 						flags |= Shell32.SIIGBF.SIIGBF_ICONONLY;
 
+					if (iconOptions.HasFlag(IconOptions.ReturnThumbnailOnly))
+						flags |= Shell32.SIIGBF.SIIGBF_THUMBNAILONLY;
+
+					if (iconOptions.HasFlag(IconOptions.ReturnOnlyIfCached))
+						flags |= Shell32.SIIGBF.SIIGBF_INCACHEONLY;
+
 					var hres = shellFactory.GetImage(new SIZE(size, size), flags, out var hbitmap);
 					if (hres == HRESULT.S_OK)
 					{
@@ -315,7 +321,7 @@ public static string ExtractStringFromDLL(string file, int number)
 					Marshal.ReleaseComObject(shellFactory);
 				}
 
-				if (iconData is not null)
+				if (iconData is not null || iconOptions.HasFlag(IconOptions.ReturnThumbnailOnly))
 					return iconData;			
 				else
 				{

src/Files.App/Utils/Storage/Helpers/FileThumbnailHelper.cs

@@ -13,9 +13,8 @@ public static class FileThumbnailHelper
 		public static async Task<byte[]?> GetIconAsync(string path, uint requestedSize, bool isFolder, IconOptions iconOptions)
 		{
 			var size = iconOptions.HasFlag(IconOptions.UseCurrentScale) ? requestedSize * App.AppModel.AppWindowDPI : requestedSize;
-			var returnIconOnly = iconOptions.HasFlag(IconOptions.ReturnIconOnly);
 
-			return await Win32Helper.StartSTATask(() => Win32Helper.GetIcon(path, (int)size, isFolder, returnIconOnly));
+			return await Win32Helper.StartSTATask(() => Win32Helper.GetIcon(path, (int)size, isFolder, iconOptions));
 		}
 
 		/// <summary>

src/Files.Core/Data/Enums/IconOptions.cs

@@ -12,21 +12,26 @@ public enum IconOptions
 		/// <summary>
 		/// Default. No options.
 		/// </summary>
-		None,
+		None = 0,
 
 		/// <summary>
 		/// Increase requested size based on the displays DPI setting.
 		/// </summary>
-		UseCurrentScale,
+		UseCurrentScale = 1,
 
 		/// <summary>
 		/// Retrieve only the file icon, even a thumbnail is available. This has the best performance.
 		/// </summary>
-		ReturnIconOnly,
+		ReturnIconOnly = 2,
+
+		/// <summary>
+		/// Retrieve only the thumbnail.
+		/// </summary>
+		ReturnThumbnailOnly = 4,
 
 		/// <summary>
 		/// Retrieve a thumbnail only if it is cached or embedded in the file.
 		/// </summary>
-		ReturnOnlyIfCached,
+		ReturnOnlyIfCached = 8,
 	}
 }