internal ChannelReceiveAwaiter <T> ReceiveAsync(IUniqueOportunity oportunity)
{
ChannelReceiveAwaiter <T> result = default(ChannelReceiveAwaiter <T>);
Func <ChannelReceiveAwaiter <T> > indirectResult = null;
_rwl.EnterWriteLock();
try
{
ReceiveAsyncInternal(ref result, ref indirectResult, oportunity);
}
finally
{
_rwl.ExitWriteLock();
}
if (indirectResult != null)
{
return(indirectResult());
}
return(result);
}
private void ReceiveAsyncInternal(ref ChannelReceiveAwaiter <T> result, ref Func <ChannelReceiveAwaiter <T> > indirectResult, IUniqueOportunity oportunity)
{
if (_buffer != null && _bufferedCount > 0)
{
if (oportunity.TryAcquire())
{
oportunity.Release(false);
result = ChannelReceiveAwaiter <T> .Done(_buffer[_bufferHead]);
_buffer[_bufferHead] = default(T);
_bufferHead = (_bufferHead + 1) % _buffer.Length;
--_bufferedCount;
if (_closing && _bufferedCount == 0 && _activeSenders.Count == 0)
{
_closed = true;
}
return;
}
else
{
result = ChannelReceiveAwaiter <T> .Never();
}
}
while (_activeSenders.Count > 0)
{
var sender = _activeSenders.First.Value;
_activeSenders.RemoveFirst();
if (sender.LockForSelection())
{
if (oportunity.TryAcquire())
{
sender.ConfirmSelection();
oportunity.Release(false);
indirectResult = () => ChannelReceiveAwaiter <T> .Done(sender.Consume());
if (_closing && _bufferedCount == 0 && _activeSenders.Count == 0)
{
_closed = true;
}
return;
}
else
{
sender.CancelSelection();
_activeSenders.AddFirst(sender);
result = ChannelReceiveAwaiter <T> .Never();
return;
}
}
}
if (_closed)
{
if (oportunity.TryAcquire())
{
oportunity.Release(false);
result = ChannelReceiveAwaiter <T> .Done(default(T));
return;
}
else
{
result = ChannelReceiveAwaiter <T> .Never();
return;
}
}
// cleanup
var current = _activeReceivers.First;
while (current != null)
{
var old = current;
current = old.Next;
if (!old.Value.IsStillListening())
{
_activeReceivers.Remove(old);
}
}
var waiter = ChannelReceiveAwaiter <T> .Waiting(oportunity);
_activeReceivers.AddLast(waiter);
result = waiter;
}