private async Task <ReceivedMqttPacket> ReceiveAsync(CancellationToken cancellationToken)
{
var readFixedHeaderResult = await _packetReader.ReadFixedHeaderAsync(_fixedHeaderBuffer, cancellationToken).ConfigureAwait(false);
if (cancellationToken.IsCancellationRequested)
{
return(null);
}
try
{
if (readFixedHeaderResult.ConnectionClosed)
{
return(null);
}
ReadingPacketStartedCallback?.Invoke();
var fixedHeader = readFixedHeaderResult.FixedHeader;
if (fixedHeader.RemainingLength == 0)
{
return(new ReceivedMqttPacket(fixedHeader.Flags, null, 2));
}
var body = new byte[fixedHeader.RemainingLength];
var bodyOffset = 0;
var chunkSize = Math.Min(ReadBufferSize, fixedHeader.RemainingLength);
do
{
var bytesLeft = body.Length - bodyOffset;
if (chunkSize > bytesLeft)
{
chunkSize = bytesLeft;
}
var readBytes = await _channel.ReadAsync(body, bodyOffset, chunkSize, cancellationToken).ConfigureAwait(false);
if (cancellationToken.IsCancellationRequested)
{
return(null);
}
if (readBytes == 0)
{
return(null);
}
bodyOffset += readBytes;
} while (bodyOffset < body.Length);
var bodyReader = new MqttPacketBodyReader(body, 0, body.Length);
return(new ReceivedMqttPacket(fixedHeader.Flags, bodyReader, fixedHeader.TotalLength));
}
finally
{
ReadingPacketCompletedCallback?.Invoke();
}
}
public async Task <MqttBasePacket> ReceivePacketAsync(TimeSpan timeout, CancellationToken cancellationToken)
{
var input = Connection.Transport.Input;
try
{
while (!cancellationToken.IsCancellationRequested)
{
ReadResult readResult;
var readTask = input.ReadAsync(cancellationToken);
if (readTask.IsCompleted)
{
readResult = readTask.Result;
}
else
{
readResult = await readTask.ConfigureAwait(false);
}
var buffer = readResult.Buffer;
var consumed = buffer.Start;
var observed = buffer.Start;
try
{
if (!buffer.IsEmpty)
{
if (PacketFormatterAdapter.TryDecode(_reader, buffer, out var packet, out consumed, out observed, out var received))
{
BytesReceived += received;
return(packet);
}
else
{
// we did receive something but the message is not yet complete
ReadingPacketStartedCallback?.Invoke();
}
}
else if (readResult.IsCompleted)
{
throw new MqttCommunicationException("Connection Aborted");
}
}
finally
{
// The buffer was sliced up to where it was consumed, so we can just advance to the start.
// We mark examined as buffer.End so that if we didn't receive a full frame, we'll wait for more data
// before yielding the read again.
input.AdvanceTo(consumed, observed);
}
}