private Task <bool> WaitToWriteAsync(CancellationToken cancellationToken = default(CancellationToken))
{
if (cancellationToken.IsCancellationRequested)
{
return(Task.FromCanceled <bool>(cancellationToken));
}
lock (SyncObj)
{
AssertInvariants();
// If we're done writing, no writes will ever succeed.
if (_doneWriting != null)
{
return(ChannelUtilities.FalseTask);
}
// If there's space to write, a write is possible.
// And if the mode involves dropping, we can always write, as even if it's
// full we'll just drop an element to make room.
if (_items.Count < _bufferedCapacity || _mode != BoundedChannelFullMode.Wait)
{
return(ChannelUtilities.TrueTask);
}
// We're still allowed to write, but there's no space, so ensure a waiter is queued and return it.
return(ChannelUtilities.GetOrCreateWaiter(ref _waitingWriters, true, cancellationToken));
}
}
private Task <bool> WaitToReadAsync(CancellationToken cancellationToken = default(CancellationToken))
{
if (cancellationToken.IsCancellationRequested)
{
return(Task.FromCanceled <bool>(cancellationToken));
}
lock (SyncObj)
{
AssertInvariants();
// If there are any items available, a read is possible.
if (!_items.IsEmpty)
{
return(ChannelUtilities.TrueTask);
}
// There were no items available, so if we're done writing, a read will never be possible.
if (_doneWriting != null)
{
return(ChannelUtilities.FalseTask);
}
// There were no items available, but there could be in the future, so ensure
// there's a blocked reader task and return it.
return(ChannelUtilities.GetOrCreateWaiter(ref _waitingReaders, _runContinuationsAsynchronously, cancellationToken));
}
}
private Task <bool> WaitToWriteAsync(CancellationToken cancellationToken = default(CancellationToken))
{
lock (SyncObj)
{
// If we're done writing, fail.
if (_completion.Task.IsCompleted)
{
return(ChannelUtilities.FalseTask);
}
// If there's a blocked reader, we can write
if (!_blockedReaders.IsEmpty)
{
return(ChannelUtilities.TrueTask);
}
// Otherwise, queue the writer
return(ChannelUtilities.GetOrCreateWaiter(ref _waitingWriters, true, cancellationToken));
}
}
private Task <bool> WaitToReadAsync(CancellationToken cancellationToken = default(CancellationToken))
{
lock (SyncObj)
{
// If we're done writing, fail.
if (_completion.Task.IsCompleted)
{
return(_completion.Task.IsFaulted ?
Task.FromException <bool>(_completion.Task.Exception.InnerException) :
ChannelUtilities.FalseTask);
}
// If there's a blocked writer, we can read.
if (!_blockedWriters.IsEmpty)
{
return(ChannelUtilities.TrueTask);
}
// Otherwise, queue the waiter.
return(ChannelUtilities.GetOrCreateWaiter(ref _waitingReaders, true, cancellationToken));
}
}
