Update SystemFolderWatcher

src/OwlCore.Storage.csproj

@@ -14,7 +14,7 @@
     <AllowedOutputExtensionsInPackageBuildOutputFolder>$(AllowedOutputExtensionsInPackageBuildOutputFolder);.pdb</AllowedOutputExtensionsInPackageBuildOutputFolder>
 
     <Author>Arlo Godfrey</Author>
-    <Version>0.11.0</Version>
+    <Version>0.11.1</Version>
     <Product>OwlCore</Product>
     <Description>The most flexible file system abstraction, ever. Built in partnership with the UWP Community.
 
@@ -23,6 +23,10 @@
     <PackageLicenseFile>LICENSE.txt</PackageLicenseFile>
     <PackageIcon>logo.png</PackageIcon>
     <PackageReleaseNotes>
+--- 0.11.1 ---
+[Fixes]
+Fixed an issue where SystemFolderWatcher would not capture any file system events.
+
 --- 0.11.0 ---
 [New]
 Added new FileReadExtensions and FileWriteExtensions for reading and writing IFile as text content or byte arrays.
@@ -280,4 +284,4 @@ Initial release of OwlCore.Storage.
       <PackagePath>\</PackagePath>
     </None>
   </ItemGroup>
-</Project>
+</Project>

src/System/IO/SystemFolderWatcher.cs

@@ -12,6 +12,7 @@ namespace OwlCore.Storage.System.IO
     public class SystemFolderWatcher : IFolderWatcher
     {
         private readonly FileSystemWatcher _watcher;
+        private event NotifyCollectionChangedEventHandler? _collectionChanged;
 
         /// <summary>
         /// Creates a new instance of <see cref="SystemFolderWatcher"/>.
@@ -43,26 +44,38 @@ private void DetachEvents(FileSystemWatcher watcher)
         private void OnCreated(object sender, FileSystemEventArgs e)
         {
             var newItem = CreateStorableFromPath(e.FullPath);
-            CollectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, new List<IStorable> { newItem }));
+            _collectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, new List<IStorable> { newItem }));
         }
 
         private void OnDeleted(object sender, FileSystemEventArgs e)
         {
             var oldItem = CreateStorableFromPath(e.FullPath, minimalImplementation: true);
-            CollectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, new List<IStorable> { oldItem }));
+            _collectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, new List<IStorable> { oldItem }));
         }
 
         private void OnRenamed(object sender, RenamedEventArgs e)
         {
             var newItem = CreateStorableFromPath(e.FullPath);
-            CollectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, new List<IStorable> { newItem }));
+            _collectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, new List<IStorable> { newItem }));
 
             var oldItem = CreateStorableFromPath(e.OldFullPath, minimalImplementation: true);
-            CollectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, new List<IStorable> { oldItem }));
+            _collectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, new List<IStorable> { oldItem }));
         }
 
         /// <inheritdoc />
-        public event NotifyCollectionChangedEventHandler? CollectionChanged;
+        public event NotifyCollectionChangedEventHandler? CollectionChanged
+        {
+            add
+            {
+                _collectionChanged += value;
+                _watcher.EnableRaisingEvents = _collectionChanged is not null;
+            }
+            remove
+            {
+                _collectionChanged -= value;
+                _watcher.EnableRaisingEvents = _collectionChanged is not null;
+            }
+        }
 
         /// <inheritdoc />
         public IMutableFolder Folder { get; }
@@ -106,7 +119,8 @@ private static IStorable CreateStorableFromPath(string path, bool minimalImpleme
                 return new SystemFile(path);
             }
 
-            throw new ArgumentException($"Could not determine if the path '{path}' is a file or folder.");
+            // The item is most likely deleted. Return all available information through SimpleStorableItem
+            return new SimpleStorableItem(id: path, name: Path.GetFileName(path));
         }
 
         private static bool IsFile(string path) => Path.GetFileName(path) is { } str && str != string.Empty && File.Exists(path);

tests/OwlCore.Storage.Tests/SystemIO/IFolderTests.cs

@@ -16,7 +16,7 @@ public override Task<IModifiableFolder> CreateModifiableFolderAsync()
     public override Task<IModifiableFolder> CreateModifiableFolderWithItems(int fileCount, int folderCount)
     {
         var tempFolder = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
-        var dir = Directory.CreateDirectory(tempFolder);
+        _ = Directory.CreateDirectory(tempFolder);
 
         for (var i = 0; i < fileCount; i++)
         {
@@ -33,4 +33,51 @@ public override Task<IModifiableFolder> CreateModifiableFolderWithItems(int file
 
         return Task.FromResult<IModifiableFolder>(new SystemFolder(tempFolder));
     }
+
+    // Folder Watcher tests
+    // TODO: Move these to CommonTests.
+
+    [TestMethod]
+    public async Task FolderWatcherOnFileCreate()
+    {
+        var folder = await CreateModifiableFolderAsync();
+
+        await using var watcher = await folder.GetFolderWatcherAsync();
+        var collectionChangedTaskCompletionSource = new TaskCompletionSource();
+        watcher.CollectionChanged += (sender, args) => collectionChangedTaskCompletionSource.SetResult();
+
+        await folder.CreateFileAsync(GetHashCode().ToString(), overwrite: true);
+
+        await collectionChangedTaskCompletionSource.Task;
+    }
+
+    [TestMethod]
+    [Timeout(2000)]
+    public async Task FolderWatcherOnFolderCreate()
+    {
+        var folder = await CreateModifiableFolderAsync();
+
+        await using var watcher = await folder.GetFolderWatcherAsync();
+        var collectionChangedTaskCompletionSource = new TaskCompletionSource();
+        watcher.CollectionChanged += (sender, args) => collectionChangedTaskCompletionSource.SetResult();
+
+        await folder.CreateFolderAsync(GetHashCode().ToString(), overwrite: true);
+
+        await collectionChangedTaskCompletionSource.Task;
+    }
+
+    [TestMethod]
+    public async Task FolderWatcherOnDelete()
+    {
+        var folder = await CreateModifiableFolderWithItems(1, 0);
+        var existingItem = await folder.GetItemsAsync(StorableType.File).FirstAsync();
+
+        await using var watcher = await folder.GetFolderWatcherAsync();
+        var collectionChangedTaskCompletionSource = new TaskCompletionSource();
+        watcher.CollectionChanged += (sender, args) => collectionChangedTaskCompletionSource.SetResult();
+
+        await folder.DeleteAsync(existingItem);
+
+        await collectionChangedTaskCompletionSource.Task;
+    }
 }