public Task WaitAsync(CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
lock (_lockObj)
{
if (_currentCount > 0)
{
--_currentCount;
return(Task.CompletedTask);
}
else
{
var task = new TaskNode();
if (_head == null)
{
_head = _tail = task;
}
else
{
_tail.Next = task;
_tail = task;
}
if (cancellationToken != CancellationToken.None)
{
task.Cancellation = cancellationToken.Register(() =>
{
task.TrySetCanceled();
if (task.Cancellation != default(CancellationTokenRegistration))
{
task.Cancellation.Dispose();
}
});
}
return(task.Task);
}
}
}