/// <summary>
/// Read data from socket into buffer and process. Check if disposed after calling this, because
/// this method will temporarily release the lock.
/// </summary>
private void ReceiveSocketData(SocketAsyncEventArgs args)
{
try {
_syncLock.TakeRead();
// exit if we're disposing
if (_disposing)
{
_syncLock.ReleaseRead();
return;
}
if (args.SocketError == SocketError.Success)
{
// how many bytes did we receive?
int count = args.BytesTransferred;
if (count > 0)
{
// enqueue these bytes to read
_receivedBuffer.TakeItem().Enqueue(args.Buffer, 0, count);
_receivedBuffer.Release();
if (_readLock.TryTake)
{
ProcessReceivedData();
}
}
// deallocate the arguments
_syncLock.ReleaseRead();
}
else
{
// deallocate the arguments
_syncLock.ReleaseRead();
if (_disposing)
{
return;
}
ProcessError("Socket Receive error '" + args.SocketError + "'.");
}
SocketEventArgsCache.DeallocateForReceive(args, OnSocketReceive);
} catch (SocketException ex) {
if (ex.SocketErrorCode == SocketError.ConnectionReset)
{
SocketEventArgsCache.DeallocateForReceive(args, OnSocketReceive);
Log.Warning("Socket connection to '" + RemoteEndPoint + "' was reset.");
}
_syncLock.ReleaseRead();
ProcessError(ex);
} catch (Exception ex) {
// we want to catch exceptions outside of the lock
_syncLock.ReleaseRead();
ProcessError(ex);
}
}
/// <summary>
/// Start receiving data from the socket.
/// </summary>
public void Start()
{
// don't start if disposing
if (_disposing)
{
return;
}
// ensure we don't start multiple times
if (Interlocked.CompareExchange(ref _started, 1, 0) == 1)
{
// already started! can't call Start() twice.
throw new InvalidOperationException("Cannot call AsyncSocket.Start() more than once.");
}
// configure for receive
var args = SocketEventArgsCache.AllocateForReceive(OnSocketReceive);
// start a receive request and immediately check to see if the receive is already complete
// otherwise OnIOCompleted will get called when the receive is complete
if (!Socket.ReceiveAsync(args))
{
ReceiveSocketData(args);
}
}
/// <summary>
/// Creates a new AsyncSocket. You must call Start() after creating the AsyncSocket
/// in order to begin receive data.
/// </summary>
internal AsyncTcpSocket(Socket socket, IPEndPoint remoteEndpoint, IPEndPoint localEndpoint,
Action <byte[], int> onReceive, Action <Exception> onError)
{
Socket = socket;
OnReceive = onReceive;
OnError = onError;
RemoteEndPoint = remoteEndpoint;
LocalEndPoint = localEndpoint;
_sendLock = new Lock();
_readLock = new Lock();
_callbackLock = new Lock();
_sendBuffer = new Shared <BufferQueue>(new BufferQueue());
_syncLock = new LockReadWrite();
_receivedBuffer = new Shared <BufferQueue>(new BufferQueue());
_onReceive = new ActionSequence();
_callbacks = new Queue <Teple <int, IAction> >();
_sendSocketArgs = SocketEventArgsCache.AllocateForSend(OnSocketSend);
_sendSocketArgs.SendPacketsFlags = TransmitFileOptions.UseKernelApc | TransmitFileOptions.UseSystemThread;
_sendSocketArgs.RemoteEndPoint = RemoteEndPoint;
_disposing = false;
}
/// <summary>
/// Complete processing a buffer of bytes read from the socket.
/// </summary>
private void CompleteReceive()
{
// ReadSocketData temporarily releases the lock (and then enters it again), so we need to ensure
// we haven't disposed in the meantime
if (_disposing)
{
_readLock.Release();
return;
}
if (_receivedBuffer.TakeItem().Length > 0)
{
_receivedBuffer.Release();
ManagerUpdate.Control.AddSingle(ProcessReceivedData);
return;
}
_receivedBuffer.Release();
// flop the processing flag
_readLock.Release();
// any bytes in the queue?
if (_receivedBuffer.TakeItem().Length > 0 && _readLock.TryTake)
{
_receivedBuffer.Release();
ManagerUpdate.Control.AddSingle(ProcessReceivedData);
return;
}
_receivedBuffer.Release();
// socket may have been closed already due to connection error.
// if not try receiving more data
if (Socket.Connected)
{
// receiveAsync returns true if the I/O operation is pending. An event will be raised upon completion.
// returns false if the I/O operation completed synchronously.
var args = SocketEventArgsCache.AllocateForReceive(OnSocketReceive);
if (!Socket.ReceiveAsync(args))
{
ReceiveSocketData(args);
}
}
else
{
if (_disposing)
{
return;
}
ProcessError("Cannot receive, socket is not connected.");
}
}
/// <summary>
/// Dispose this AsyncSocket. Closes the underlying socket if required.
/// </summary>
public void Dispose()
{
// ensure we haven't already disposed
_syncLock.TakeWrite();
if (_disposing)
{
_syncLock.ReleaseWrite();
return;
}
_disposing = true;
_syncLock.ReleaseWrite();
// run sender dispose code
if (_sendSocketArgs != null)
{
SocketEventArgsCache.DeallocateForSend(_sendSocketArgs, OnSocketSend);
_sendSocketArgs = null;
}
}
