|
public static MergeAndMask ( int mask, ArraySegment |
||
| mask | int | |
| header | ArraySegment |
|
| data | ArraySegment |
|
| return | byte[] | |
private async void SendKeepAliveAsync()
{
// Check concurrent writes, pings & pongs, or closes
if (!_writeLock.Wait(0))
{
// Sending real data is better than a ping, discard it.
return;
}
try
{
if (State == WebSocketState.CloseSent || State >= WebSocketState.Closed)
{
_keepAliveTimer.Dispose();
return;
}
int mask = GetNextMask();
FrameHeader frameHeader = new FrameHeader(true, Constants.OpCodes.PingFrame, _maskOutput, mask, PingBuffer.Length);
ArraySegment <byte> headerSegment = frameHeader.Buffer;
// TODO: CancelationToken / timeout?
if (_maskOutput && mask != 0)
{
byte[] maskedFrame = Utilities.MergeAndMask(mask, headerSegment, new ArraySegment <byte>(PingBuffer));
await _stream.WriteAsync(maskedFrame, 0, maskedFrame.Length);
}
else
{
await _stream.WriteAsync(headerSegment.Array, headerSegment.Offset, headerSegment.Count);
await _stream.WriteAsync(PingBuffer, 0, PingBuffer.Length);
}
}
catch (Exception)
{
// TODO: Log exception, this is a background thread.
// Shut down, we must be in a faulted state;
Abort();
}
finally
{
_writeLock.Release();
}
}
public override async Task SendAsync(ArraySegment <byte> buffer, WebSocketMessageType messageType, bool endOfMessage, CancellationToken cancellationToken)
{
ValidateSegment(buffer);
if (messageType != WebSocketMessageType.Binary && messageType != WebSocketMessageType.Text)
{
// Block control frames
throw new ArgumentOutOfRangeException(nameof(messageType), messageType, string.Empty);
}
// Check concurrent writes, pings & pongs, or closes
await _writeLock.WaitAsync(cancellationToken);
try
{
ThrowIfDisposed();
ThrowIfOutputClosed();
int mask = GetNextMask();
int opcode = _isOutgoingMessageInProgress ? Constants.OpCodes.ContinuationFrame : Utilities.GetOpCode(messageType);
FrameHeader frameHeader = new FrameHeader(endOfMessage, opcode, _maskOutput, mask, buffer.Count);
ArraySegment <byte> headerSegment = frameHeader.Buffer;
if (_maskOutput && mask != 0)
{
// TODO: For larger messages consider using a limited size buffer and masking & sending in segments.
byte[] maskedFrame = Utilities.MergeAndMask(mask, headerSegment, buffer);
await _stream.WriteAsync(maskedFrame, 0, maskedFrame.Length, cancellationToken);
}
else
{
await _stream.WriteAsync(headerSegment.Array, headerSegment.Offset, headerSegment.Count, cancellationToken);
await _stream.WriteAsync(buffer.Array, buffer.Offset, buffer.Count, cancellationToken);
}
_isOutgoingMessageInProgress = !endOfMessage;
}
finally
{
_writeLock.Release();
}
}