/// <inheritdoc />
public void Dispose()
{
if (generatorTask == null)
{
return;
}
#endif
// Notify the cancellation.
if (lastCombinedCancellationTokenSource != taskCompletionTokenSource)
{
lastCombinedCancellationTokenSource.Dispose();
}
taskCompletionTokenSource.Cancel();
taskCompletionTokenSource.Dispose();
// Do cleanup.
buffer.Terminate();
lastCombinedCancellationTokenSource = null;
taskCompletionTokenSource = null;
lastMoveNextCancellationToken = CancellationToken.None;
buffer = null;
generatorTask = null;
#if CLR_FEATURE_ASYNC_STREAM
return(new ValueTask());
#endif
}
/// <inheritdoc />
public async Task <bool> MoveNext(CancellationToken cancellationToken)
#endif
{
if (generatorTask == null)
{
buffer = new AsyncEnumerableBuffer <T>();
generatorTask = generator(buffer, cancellationToken);
taskCompletionTokenSource = new CancellationTokenSource();
var forgetit = generatorTask.ContinueWith((_, cts) =>
((CancellationTokenSource)cts).Cancel(), taskCompletionTokenSource,
taskCompletionTokenSource.Token);
lastCombinedCancellationTokenSource = taskCompletionTokenSource;
}
cancellationToken.ThrowIfCancellationRequested();
if (buffer.TryTake(out var cur))
{
Current = cur;
return(true);
}
// Currently no items available.
if (generatorTask.IsCompleted)
{
PropagateGeneratorException();
return(false);
}
// Slow route
if (cancellationToken != lastMoveNextCancellationToken)
{
lastMoveNextCancellationToken = cancellationToken;
if (lastCombinedCancellationTokenSource != taskCompletionTokenSource)
{
lastCombinedCancellationTokenSource.Dispose();
}
lastCombinedCancellationTokenSource = cancellationToken.CanBeCanceled
? CancellationTokenSource.CreateLinkedTokenSource(taskCompletionTokenSource.Token, cancellationToken)
: taskCompletionTokenSource;
}
try
{
Current = await buffer.Take(lastCombinedCancellationTokenSource.Token).ConfigureAwait(false);
return(true);
}
catch (OperationCanceledException)
{
if (cancellationToken.IsCancellationRequested)
{
throw;
}
PropagateGeneratorException();
return(false);
}
}
/// <inheritdoc />
public void Dispose()
{
if (generatorTask == null)
{
return;
}
// Notify the cancellation.
if (lastCombinedCancellationTokenSource != taskCompletionTokenSource)
{
lastCombinedCancellationTokenSource.Dispose();
}
taskCompletionTokenSource.Cancel();
taskCompletionTokenSource.Dispose();
// Do cleanup.
buffer.Terminate();
lastCombinedCancellationTokenSource = null;
taskCompletionTokenSource = null;
lastMoveNextCancellationToken = CancellationToken.None;
buffer = null;
generatorTask = null;
}
