public Task WaitAsync(CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return(Task.FromCanceled(cancellationToken));
}
lock (_signalAwaiters)
{
if (_signaled)
{
_signaled = false;
return(Task.CompletedTask);
}
else
{
var waiter = new WaiterCompletionSource(this, _allowInliningAwaiters, cancellationToken);
if (cancellationToken.IsCancellationRequested)
{
waiter.TrySetCanceled(cancellationToken);
}
else
{
_signalAwaiters.Enqueue(waiter);
}
return(waiter.Task);
}
}
}
/// <summary>
/// Returns an awaitable that may be used to asynchronously acquire the next signal.
/// </summary>
/// <param name="cancellationToken">A token whose cancellation removes the caller from the queue of those waiting for the event.</param>
/// <returns>An awaitable.</returns>
public Task WaitAsync(CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return(ThreadingTools.TaskFromCanceled(cancellationToken));
}
lock (this.signalAwaiters)
{
if (this.signaled)
{
this.signaled = false;
return(TplExtensions.CompletedTask);
}
else
{
var waiter = new WaiterCompletionSource(this, cancellationToken, this.allowInliningAwaiters);
if (cancellationToken.IsCancellationRequested)
{
waiter.TrySetCanceled(cancellationToken);
}
else
{
this.signalAwaiters.Enqueue(waiter);
}
return(waiter.Task);
}
}
}
public ValueTask <AsyncLockObject> LockAsync(CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return(ValueTask.FromCanceled <AsyncLockObject>(cancellationToken));
}
lock (_signalAwaiters)
{
if (_signaled)
{
_signaled = false;
return(new ValueTask <AsyncLockObject>(new AsyncLockObject(this)));
}
else
{
var waiter = new WaiterCompletionSource(this, _allowInliningAwaiters, cancellationToken);
if (cancellationToken.IsCancellationRequested)
{
waiter.TrySetCanceled(cancellationToken);
}
else
{
_signalAwaiters.Enqueue(waiter);
}
return(new ValueTask <AsyncLockObject>(waiter.Task));
}
}
}
/// <summary>
/// Sets the signal if it has not already been set, allowing one awaiter to handle the signal if one is already waiting.
/// </summary>
public void Set()
{
WaiterCompletionSource toRelease = null;
lock (this.signalAwaiters)
{
if (this.signalAwaiters.Count > 0)
{
toRelease = this.signalAwaiters.Dequeue();
}
else if (!this.signaled)
{
this.signaled = true;
}
}
if (toRelease != null)
{
toRelease.Registration.Dispose();
toRelease.TrySetResultToDefault();
}
}
