Fix ToSignal to throw OperationCanceledException

README.md

@@ -46,8 +46,14 @@ public Test : Node
 		var cts = new CancellationTokenSource();
 		WaitAndEmitMySignal(TimeSpan.FromSeconds(2)).Forget();
 		WaitAndCancelToken(TimeSpan.FromSeconds(1), cts).Forget();
-		var signalResults = await GDTask.ToSignal(this, nameof(MySignal), cts.Token);
-		// signalResults = null, since we cancelled awaiting the signal before the signal could fire.
+		try 
+		{
+			var signalResults = await GDTask.ToSignal(this, nameof(MySignal), cts.Token);
+		}
+		catch (OperationCanceledException _)
+		{
+			GD.Print("Awaiting MySignal cancelled!");
+		}
 
 		// Waiting a single frame
 		await GDTask.Yield();

addons/GDTask/GDTask.ToSignal.cs

@@ -1,89 +1,25 @@
 using Godot;
-using System;
-using System.Runtime.CompilerServices;
 using System.Threading;
 
 namespace Fractural.Tasks
 {
-    /// <summary>
-    /// A cancellable signal awaiter that wraps the Godot <see cref="SignalAwaiter"/>. Using ToSignal 
-    /// with an additional <see cref="CancellationToken"/> as parameter automatically returns this awaiter. 
-    /// See <see cref="GodotObjectExtensions.ToSignal(GodotObject, GodotObject, StringName, CancellationToken)"/>.
-    /// 
-    /// Originally from <see href="https://github.com/altamkp/GodotEx/blob/master/src/GodotEx.Async/src/Core/CancellableSignalAwaiter.cs">GodotEx</see>
-    /// </summary>
-    public class CancellableSignalAwaiter : IAwaiter<Variant[]>, INotifyCompletion, IAwaitable<Variant[]>
-    {
-        private readonly SignalAwaiter _signalAwaiter;
-        private readonly CancellationToken _cancellationToken;
-        private readonly CancellationTokenRegistration _cancellationTokenRegistration;
-
-        private Action? _continuation;
-        private bool _isCancelled;
-
-        /// <summary>
-        /// Creates a new <see cref="CancellableSignalAwaiter"/> that wraps the Godot <see cref="SignalAwaiter"/>.
-        /// </summary>
-        /// <param name="signalAwaiter">Godot <see cref="SignalAwaiter"/>.</param>
-        /// <param name="cancellationToken">Cancellation token for cancellation request.</param>
-        public CancellableSignalAwaiter(SignalAwaiter signalAwaiter, CancellationToken cancellationToken)
-        {
-            _signalAwaiter = signalAwaiter;
-            _cancellationToken = cancellationToken;
-            _cancellationTokenRegistration = _cancellationToken.Register(() =>
-            {
-                _cancellationTokenRegistration.Dispose();
-                _isCancelled = true;
-                OnAwaiterCompleted();
-            });
-        }
-
-        /// <summary>
-        /// Completion status of the awaiter. True if canceled or if signal is emitted.
-        /// </summary>
-        public bool IsCompleted => _isCancelled || _signalAwaiter.IsCompleted;
-
-        /// <summary>
-        /// Registers action delegate upon completion.
-        /// </summary>
-        /// <param name="continuation">Action delegate up completion.</param>
-        public void OnCompleted(Action continuation)
-        {
-            _continuation = continuation;
-            _signalAwaiter.OnCompleted(OnAwaiterCompleted);
-        }
-
-        /// <summary>
-        /// Returns current awaiter as <see cref="IAwaiter"/> that can be used with the await keyword.
-        /// </summary>
-        /// <returns>Current awaiter as <see cref="IAwaiter"/>.</returns>
-        public IAwaiter<Variant[]> GetAwaiter() => this;
-
-        /// <summary>
-        /// Returns result upon completion.
-        /// </summary>
-        /// <returns>Result upon completion.</returns>
-        public Variant[] GetResult() => _signalAwaiter.GetResult();
-
-        private void OnAwaiterCompleted()
-        {
-            var continuation = _continuation;
-            _continuation = null;
-            continuation?.Invoke();
-        }
-    }
-
     public partial struct GDTask
     {
-        public static async GDTask<Variant[]> ToSignal(GodotObject self, string signal)
+        public static async GDTask<Variant[]> ToSignal(GodotObject self, StringName signal)
         {
             return await self.ToSignal(self, signal);
         }
 
-        public static async GDTask<Variant[]> ToSignal(GodotObject self, string signal, CancellationToken ct)
+        public static async GDTask<Variant[]> ToSignal(GodotObject self, StringName signal, CancellationToken ct)
         {
-            var cancellableSignalAwaiter = new CancellableSignalAwaiter(self.ToSignal(self, signal), ct);
-            return await cancellableSignalAwaiter;
+            var tcs = new GDTaskCompletionSource<Variant[]>();
+            ct.Register(() => tcs.TrySetCanceled(ct));
+            Create(async () =>
+            {
+                var result = await self.ToSignal(self, signal);
+                tcs.TrySetResult(result);
+            }).Forget();
+            return await tcs.Task;
         }
     }
 }

tests/manual/Test.cs

@@ -85,15 +85,29 @@ private async GDTaskVoid Run()
             GD.Print("Run: Await Cancellable MyEmptySignal");
             WaitAndEmitMyEmptySignal(TimeSpan.FromSeconds(3)).Forget();
             WaitAndCancelToken(TimeSpan.FromSeconds(0.5), cts).Forget();
-            signalResult = await GDTask.ToSignal(this, nameof(MyEmptySignal), cts.Token);
-            GD.Print("Run: Await Cancellable MyEmptySignal Cancelled, result: ", signalResult);
+            try
+            {
+                signalResult = await GDTask.ToSignal(this, nameof(MyEmptySignal), cts.Token);
+                GD.Print("Run: Await Cancellable MyEmptySignal ran with result: ", signalResult);
+            }
+            catch (OperationCanceledException _)
+            {
+                GD.Print("Run: Await Cancellable MyEmptySignal Cancelled");
+            }
 
             cts = new CancellationTokenSource();
             GD.Print("Run: Await Cancellable MyArgSignal");
             WaitAndEmitMyArgSignal(TimeSpan.FromSeconds(3)).Forget();
             WaitAndCancelToken(TimeSpan.FromSeconds(0.5), cts).Forget();
-            signalResult = await GDTask.ToSignal(this, nameof(MyArgSignal), cts.Token);
-            GD.Print("Run: Await Cancellable MyArgSignal Cancelled, result: ", signalResult);
+            try
+            {
+                signalResult = await GDTask.ToSignal(this, nameof(MyArgSignal), cts.Token);
+                GD.Print("Run: Await Cancellable MyArgSignal ran with result: ", signalResult);
+            }
+            catch (OperationCanceledException _)
+            {
+                GD.Print("Run: Await Cancellable MyArgSignal Cancelled");
+            }
 
             GD.Print("Run: Pre RunWithResult");
             string runResult = await RunWithResult();