/// <summary>Wake up all of the waiters and null out the field.</summary>
/// <param name="waiters">The waiters.</param>
/// <param name="result">The success value with which to complete each waiter if <paramref name="error">error</paramref> is null.</param>
/// <param name="error">The failure with which to cmplete each waiter, if non-null.</param>
internal static void WakeUpWaiters(ref ReaderInteractor <bool> waiters, bool result, Exception error = null)
{
ReaderInteractor <bool> w = waiters;
if (w != null)
{
if (error != null)
{
w.Fail(error);
}
else
{
w.Success(result);
}
waiters = null;
}
}
private bool TryComplete(Exception error = null)
{
object blockedReader = null;
ReaderInteractor <bool> waitingReader = null;
bool completeTask = false;
lock (SyncObj)
{
// If we're already marked as complete, there's nothing more to do.
if (_doneWriting != null)
{
return(false);
}
// Mark as complete for writing.
_doneWriting = error ?? ChannelUtilities.DoneWritingSentinel;
// If we have no more items remaining, then the channel needs to be marked as completed
// and readers need to be informed they'll never get another item. All of that needs
// to happen outside of the lock to avoid invoking continuations under the lock.
if (_items.IsEmpty)
{
completeTask = true;
if (_blockedReader != null)
{
blockedReader = _blockedReader;
_blockedReader = null;
}
if (_waitingReader != null)
{
waitingReader = _waitingReader;
_waitingReader = null;
}
}
}
// Complete the channel task if necessary
if (completeTask)
{
ChannelUtilities.Complete(_completion, error);
}
Debug.Assert(blockedReader == null || waitingReader == null, "There should only ever be at most one reader.");
// Complete a blocked reader if necessary
if (blockedReader != null)
{
error = ChannelUtilities.CreateInvalidCompletionException(error);
ReaderInteractor <T> interactor = blockedReader as ReaderInteractor <T>;
if (interactor != null)
{
interactor.Fail(error);
}
else
{
((AutoResetAwaiter <T>)blockedReader).SetException(error);
}
}
// Complete a waiting reader if necessary. (We really shouldn't have both a blockedReader
// and a waitingReader, but it's more expensive to prevent it than to just tolerate it.)
if (waitingReader != null)
{
if (error != null)
{
waitingReader.Fail(error);
}
else
{
waitingReader.Success(false);
}
}
// Successfully completed the channel
return(true);
}