Use RVTS

Author: ManickaP

src/libraries/System.Net.Quic/src/System/Net/Quic/Internal/ValueTaskSource.cs

@@ -25,15 +25,13 @@ private enum State : byte
     private State _state;
     private ManualResetValueTaskSourceCore<bool> _valueTaskSource;
     private CancellationTokenRegistration _cancellationRegistration;
-    private Exception? _exception;
     private GCHandle _keepAlive;
 
     public ValueTaskSource()
     {
         _state = State.None;
         _valueTaskSource = new ManualResetValueTaskSourceCore<bool>() { RunContinuationsAsynchronously = true };
         _cancellationRegistration = default;
-        _exception = default;
         _keepAlive = default;
     }
 
@@ -77,7 +75,7 @@ public bool TryInitialize(out ValueTask valueTask, object? keepAlive = null, Can
             State state = _state;
 
             // If we're the first here, we will return true.
-            if (state == State.None && _valueTaskSource.GetStatus(_valueTaskSource.Version) == ValueTaskSourceStatus.Pending)
+            if (state == State.None)
             {
                 // Keep alive the caller object until the result is read from the task.
                 // Used for keeping caller alive during async interop calls.
@@ -106,42 +104,30 @@ private bool TryComplete(Exception? exception)
                 {
                     State state = _state;
 
-                    // Completed: nothing to do.
-                    if (state == State.Completed)
+                    if (state != State.Completed)
                     {
-                        return false;
-                    }
-
-                    // With cancellation, keep the state as-is so it can be restored after the OCE is consumed.
-                    _state = exception is OperationCanceledException ? state : State.Completed;
+                        _state = State.Completed;
 
-                    // Swap the cancellation registration so the one that's been registered gets eventually Disposed.
-                    // Ideally, we would dispose it here, but if the callbacks kicks in, it tries to take the lock held by this thread leading to deadlock.
-                    cancellationRegistration = _cancellationRegistration;
-                    _cancellationRegistration = default;
+                        // Swap the cancellation registration so the one that's been registered gets eventually Disposed.
+                        // Ideally, we would dispose it here, but if the callbacks kicks in, it tries to take the lock held by this thread leading to deadlock.
+                        cancellationRegistration = _cancellationRegistration;
+                        _cancellationRegistration = default;
 
-                    if (exception is not null)
-                    {
-                        // Set up the exception stack trace for the caller.
-                        exception = exception.StackTrace is null ? ExceptionDispatchInfo.SetCurrentStackTrace(exception) : exception;
-                        if (_valueTaskSource.GetStatus(_valueTaskSource.Version) == ValueTaskSourceStatus.Pending)
+                        if (exception is not null)
                         {
+                            // Set up the exception stack trace for the caller.
+                            exception = exception.StackTrace is null ? ExceptionDispatchInfo.SetCurrentStackTrace(exception) : exception;
                             _valueTaskSource.SetException(exception);
                         }
-                        else if (exception is not OperationCanceledException)
-                        {
-                            _exception = exception;
-                        }
-                    }
-                    else
-                    {
-                        if (_valueTaskSource.GetStatus(_valueTaskSource.Version) == ValueTaskSourceStatus.Pending)
+                        else
                         {
                             _valueTaskSource.SetResult(true);
                         }
+
+                        return true;
                     }
 
-                    return true;
+                    return false;
                 }
                 finally
                 {
@@ -187,34 +173,5 @@ void IValueTaskSource.OnCompleted(Action<object?> continuation, object? state, s
         => _valueTaskSource.OnCompleted(continuation, state, token, flags);
 
     void IValueTaskSource.GetResult(short token)
-    {
-        try
-        {
-            _valueTaskSource.GetResult(token);
-        }
-        finally
-        {
-            lock (this)
-            {
-                State state = _state;
-
-                // In case of a cancellation, reset the task and set the stored results if necessary.
-                if (_valueTaskSource.GetStatus(_valueTaskSource.Version) == ValueTaskSourceStatus.Canceled)
-                {
-                    _valueTaskSource.Reset();
-                    if (state == State.Completed)
-                    {
-                        if (_exception is not null)
-                        {
-                            _valueTaskSource.SetException(_exception);
-                        }
-                        else
-                        {
-                            _valueTaskSource.SetResult(true);
-                        }
-                    }
-                }
-            }
-        }
-    }
+        => _valueTaskSource.GetResult(token);
 }

src/libraries/System.Net.Quic/src/System/Net/Quic/QuicConnection.cs

@@ -109,7 +109,26 @@ static async ValueTask<QuicConnection> StartConnectAsync(QuicClientConnectionOpt
     private int _disposed;
 
     private readonly ValueTaskSource _connectedTcs = new ValueTaskSource();
-    private readonly ValueTaskSource _shutdownTcs = new ValueTaskSource();
+    private readonly ResettableValueTaskSource _shutdownTcs = new ResettableValueTaskSource()
+    {
+        CancellationAction = target =>
+        {
+            try
+            {
+                if (target is QuicConnection connection)
+                {
+                    // The OCE will be propagated through stored CancellationToken in ResettableValueTaskSource.
+                    connection._shutdownTcs.TrySetResult();
+                }
+            }
+            catch (ObjectDisposedException)
+            {
+                // We collided with a Dispose in another thread. This can happen
+                // when using CancellationTokenSource.CancelAfter.
+                // Ignore the exception
+            }
+        }
+    };
 
     private readonly CancellationTokenSource _shutdownTokenSource = new CancellationTokenSource();
 
@@ -467,7 +486,7 @@ public ValueTask CloseAsync(long errorCode, CancellationToken cancellationToken
     {
         ObjectDisposedException.ThrowIf(_disposed == 1, this);
 
-        if (_shutdownTcs.TryInitialize(out ValueTask valueTask, this, cancellationToken))
+        if (_shutdownTcs.TryGetValueTask(out ValueTask valueTask, this, cancellationToken))
         {
             unsafe
             {
@@ -626,7 +645,7 @@ public async ValueTask DisposeAsync()
         }
 
         // Check if the connection has been shut down and if not, shut it down.
-        if (_shutdownTcs.TryInitialize(out ValueTask valueTask, this))
+        if (_shutdownTcs.TryGetValueTask(out ValueTask valueTask, this))
         {
             unsafe
             {
@@ -648,7 +667,7 @@ public async ValueTask DisposeAsync()
         }
 
         // Wait for SHUTDOWN_COMPLETE, the last event, so that all resources can be safely released.
-        await valueTask.ConfigureAwait(false);
+        await _shutdownTcs.GetFinalTask(this).ConfigureAwait(false);
         Debug.Assert(_connectedTcs.IsCompleted);
         _handle.Dispose();
         _shutdownTokenSource.Dispose();