// static helper functions /////////////////////////////////////////////
// send message (via stream) with the <size,content> message structure
// this function is blocking sometimes!
// (e.g. if someone has high latency or wire was cut off)
protected static bool SendMessagesBlocking(TCPSession session, byte[][] messages)
{
// stream.Write throws exceptions if client sends with high
// frequency and the server stops
try
{
// we might have multiple pending messages. merge into one
// packet to avoid TCP overheads and improve performance.
int packetSize = 0;
for (int i = 0; i < messages.Length; ++i)
{
packetSize += sizeof(int) + messages[i].Length; // header + content
}
byte[] payload = new byte[packetSize];
// create the packet
int position = 0;
for (int i = 0; i < messages.Length; ++i)
{
// create header buffer if not created yet
if (header == null)
{
header = new byte[4];
}
// construct header (size)
Utils.IntToBytesBigEndianNonAlloc(messages[i].Length, header);
// copy header + message into buffer
Array.Copy(header, 0, payload, position, header.Length);
Array.Copy(messages[i], 0, payload, position + header.Length, messages[i].Length);
position += header.Length + messages[i].Length;
}
// write the whole thing
session.Send(payload);
//Logger.LogWarning("已发送 size:"+packetSize+ " packetNum:"+messages.Length);
return(true);
}
catch (Exception exception)
{
// log as regular message because servers do shut down sometimes
Logger.Log("Send: stream.Write exception: " + exception);
return(false);
}
}
// thread receive function is the same for client and server's clients
// (static to reduce state for maximum reliability)
protected static void ReceiveLoop(int connectionId, TCPSession session, ConcurrentQueue <Message> receiveQueue)
{
// add connected event to queue with ip address as data in case
// it's needed
receiveQueue.Enqueue(new Message(connectionId, EventType.Connected, null));
session.OnRecevePackets = (content) =>
{
receiveQueue.Enqueue(new Message(connectionId, EventType.Data, content));
};
session.OnDisconnect = (DisconnectReason disconnectReason) =>
{
receiveQueue.Enqueue(new Message(connectionId, EventType.Disconnected, null, disconnectReason));
};
}
private void receiveLoop(TCPSession session, string ip, int port)
{
try
{
session.Connect(ip, port);
}
catch (Exception e)
{
receiveQueue.Enqueue(new Message(0, EventType.Disconnected, null, DisconnectReason.ConnectionFailed));
throw e;
}
//Logger.Log("0 session.Connected" + session.Connected);
// run the receive loop
ReceiveLoop(0, session, receiveQueue);
//Logger.Log("1 session.Connected" + session.Connected);
//sendThread?.Interrupt();
sendThread = new Thread(() => { SendLoop(0, session, sendQueue, sendPending); });
sendThread.IsBackground = true;
sendThread.Start();
}
// thread send function
// note: we really do need one per connection, so that if one connection
// blocks, the rest will still continue to get sends
protected static void SendLoop(int connectionId, TCPSession session, SafeQueue <byte[]> sendQueue, ManualResetEvent sendPending)
{
// get NetworkStream from client
try
{
//Logger.Log("1.5 session.Connected" + session.Connected);
while (session.Connected) // try this. client will get closed eventually.
{
// reset ManualResetEvent before we do anything else. this
// way there is no race condition. if Send() is called again
// while in here then it will be properly detected next time
// -> otherwise Send might be called right after dequeue but
// before .Reset, which would completely ignore it until
// the next Send call.
sendPending.Reset(); // WaitOne() blocks until .Set() again
// dequeue all
// SafeQueue.TryDequeueAll is twice as fast as
// ConcurrentQueue, see SafeQueue.cs!
byte[][] messages;
if (sendQueue.TryDequeueNum(out messages, 50))
{
// send message (blocking) or stop if stream is closed
if (!SendMessagesBlocking(session, messages))
{
break; // break instead of return so stream close still happens!
}
}
// don't choke up the CPU: wait until queue not empty anymore
sendPending.WaitOne();
}
//Logger.Log("session.Connected:" + session.Connected);
}
catch (ThreadAbortException)
{
// happens on stop. don't log anything.
//Logger.LogError(e.ToString());
}
catch (ThreadInterruptedException)
{
// happens if receive thread interrupts send thread.
//Logger.LogError(e.ToString());
}
catch (Exception exception)
{
// something went wrong. the thread was interrupted or the
// connection closed or we closed our own connection or ...
// -> either way we should stop gracefully
Logger.Log("SendLoop Exception: connectionId=" + connectionId + " reason: " + exception);
}
finally
{
// clean up no matter what
// we might get SocketExceptions when sending if the 'host has
// failed to respond' - in which case we should close the connection
// which causes the ReceiveLoop to end and fire the Disconnected
// message. otherwise the connection would stay alive forever even
// though we can't send anymore.
session.Close(DisconnectReason.ConnectionFailed);
}
}