// Queue up a fully rendered frame to send
public Task WriteFrameAsync(Frame frame, Priority priority)
{
PriorityQueueEntry entry = new PriorityQueueEntry(frame, priority);
Enqueue(entry);
SignalDataAvailable();
return entry.Task;
}
// Completes when any frames ahead of it have been processed
// TODO: Have this only flush messages from one specific HTTP2Stream
public Task FlushAsync(/*int streamId, */ Priority priority)
{
if (!IsDataAvailable)
{
return Task.FromResult<object>(null);
}
PriorityQueueEntry entry = new PriorityQueueEntry(priority);
Enqueue(entry);
SignalDataAvailable();
return entry.Task;
}
public bool TryDequeue(out PriorityQueueEntry entry)
{
lock (_queueLock)
{
if (_queue.Count == 0)
{
entry = null;
return false;
}
entry = _queue.First.Value;
_queue.RemoveFirst();
return true;
}
}
// TODO: How can we make enqueue faster than O(n) and still maintain O(1) dequeue?
public void Enqueue(PriorityQueueEntry entry)
{
lock (_queueLock)
{
// Scan backwards, so we end up in order behind other items of the same priority.
LinkedListNode<PriorityQueueEntry> current = _queue.Last;
/* Disabled until it can be refactored. Header frames must never be re-ordered due to compression.
while (current != null && current.Value.Priority > entry.Priority)
{
current = current.Previous;
}
*/
if (current == null)
{
// New entry is highest priority (the list may be empty).
_queue.AddFirst(entry);
}
else
{
_queue.AddAfter(current, entry);
}
}
}
// Queue up a fully rendered frame to send
public void WriteFrame(Frame frame)
{
//Do not write to already closed stream
if (frame.FrameType != FrameType.Settings
&& frame.FrameType != FrameType.GoAway
&& frame.FrameType != FrameType.Ping
&& _streams[frame.StreamId] == null)
{
return;
}
var priority = frame.StreamId != 0 ? _streams[frame.StreamId].Priority : Priority.Pri7;
IQueueItem entry;
if (IsPriorityTurnedOn)
{
entry = new PriorityQueueEntry(frame, priority);
}
else
{
entry = new QueueEntry(frame);
}
_messageQueue.Enqueue(entry);
}
private bool TryDequeue(out PriorityQueueEntry entry)
{
return _messageQueue.TryDequeue(out entry);
}
private void Enqueue(PriorityQueueEntry entry)
{
_messageQueue.Enqueue(entry);
}