c#网络通信框架networkcomms内核解析之五 数据监听

NetworkComms网络通信框架序言

本文基于networkcomms2.3.1开源版本 gplv3协议

在networkcomms中，服务器端可以同步监听数据，也可以异步监听数据。

以开源的networkcomms.2.31为例

服务器端监听代码：

 PRotected override void StartIncomingDataListen()        {            if (!NetworkComms.ConnectionExists(ConnectionInfo.RemoteEndPoint, ConnectionType.TCP))            {                CloseConnection(true, 18);                throw new ConnectionSetupException("A connection reference by endPoint should exist before starting an incoming data listener.");            }#if WINDOWS_PHONE            var stream = socket.InputStream.AsStreamForRead();            stream.BeginRead(dataBuffer, 0, dataBuffer.Length, new AsyncCallback(IncomingTCPPacketHandler), stream);   #else            lock (delegateLocker)            {                //同步监听模式                if (NetworkComms.ConnectionListenModeUseSync)                {                    if (incomingDataListenThread == null)                    {                        incomingDataListenThread = new Thread(IncomingTCPDataSyncWorker);                        //Incoming data always gets handled in a time critical fashion                        incomingDataListenThread.Priority = NetworkComms.timeCriticalThreadPriority;                        incomingDataListenThread.Name = "IncomingDataListener";                        incomingDataListenThread.Start();                    }                }                //异步监听模式                else                    tcpClientNetworkStream.BeginRead(dataBuffer, 0, dataBuffer.Length, new AsyncCallback(IncomingTCPPacketHandler), tcpClientNetworkStream);            }#endif            if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Listening for incoming data from " + ConnectionInfo);        }

我们以异步监听为例，分析一下监听进入的数据的过程（同步监听类似)

  /// <summary>        /// Asynchronous incoming connection data delegate        /// </summary>        /// <param name="ar">The call back state object</param>        void IncomingTCPPacketHandler(IAsyncResult ar)        {            //Initialised with true so that logic still works in WP8            bool dataAvailable = true;#if !WINDOWS_PHONE            //Incoming data always gets handled in a timeCritical fashion at this point            Thread.CurrentThread.Priority = NetworkComms.timeCriticalThreadPriority;            //int bytesRead;#endif            try            {#if WINDOWS_PHONE                var stream = ar.AsyncState as Stream;                var count = stream.EndRead(ar);                totalBytesRead = count + totalBytesRead;#else                NetworkStream netStream = (NetworkStream)ar.AsyncState;                if (!netStream.CanRead)                    throw new ObjectDisposedException("Unable to read from stream.");                totalBytesRead = netStream.EndRead(ar) + totalBytesRead;                dataAvailable = netStream.DataAvailable;#endif                if (totalBytesRead > 0)                {                    //收到数据后，更新连接信息类上的数据最后传输时间                    ConnectionInfo.UpdateLastTrafficTime();                    //If we have read a single byte which is 0 and we are not expecting other data                    if (totalBytesRead == 1 && dataBuffer[0] == 0 && packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached == 0)                    {                        if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... null packet removed in IncomingPacketHandler() from " + ConnectionInfo + ". 1");                    }                    else                    {                        //if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... " + totalBytesRead.ToString() + " bytes added to packetBuilder.");                        //If there is more data to get then add it to the packets lists;                        //添加数据到“数据包创建器”（packetBuilder)中                        packetBuilder.AddPartialPacket(totalBytesRead, dataBuffer);#if !WINDOWS_PHONE                        //If we have more data we might as well continue reading syncronously                        //In order to deal with data as soon as we think we have sufficient we will leave this loop                        //当接收到的数据小于数据包的大小的时候，循环接收                        while (dataAvailable && packetBuilder.TotalBytesCached < packetBuilder.TotalBytesExpected)                        {                            int bufferOffset = 0;                            //We need a buffer for our incoming data                            //First we try to reuse a previous buffer                            if (packetBuilder.TotalPartialPacketCount > 0 && packetBuilder.NumUnusedBytesMostRecentPartialPacket() > 0)                                dataBuffer = packetBuilder.RemoveMostRecentPartialPacket(ref bufferOffset);                            else                                //If we have nothing to reuse we allocate a new buffer                                dataBuffer = new byte[NetworkComms.ReceiveBufferSizeBytes];                            //从数据流中接收数据                            totalBytesRead = netStream.Read(dataBuffer, bufferOffset, dataBuffer.Length - bufferOffset) + bufferOffset;                            if (totalBytesRead > 0)                            {                                ConnectionInfo.UpdateLastTrafficTime();                                //If we have read a single byte which is 0 and we are not expecting other data                                if (totalBytesRead == 1 && dataBuffer[0] == 0 && packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached == 0)                                {                                    if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... null packet removed in IncomingPacketHandler() from " + ConnectionInfo + ". 2");                                    //LastTrafficTime = DateTime.Now;                                }                                else                                {                                    //if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... " + totalBytesRead.ToString() + " bytes added to packetBuilder for connection with " + ConnectionInfo + ". Cached " + packetBuilder.TotalBytesCached.ToString() + "B, expecting " + packetBuilder.TotalBytesExpected.ToString() + "B.");                                    packetBuilder.AddPartialPacket(totalBytesRead, dataBuffer);                                    dataAvailable = netStream.DataAvailable;                                }                            }                            else                                break;                        }#endif                    }                }                //如果接收到的数据足够的多                if (packetBuilder.TotalBytesCached > 0 && packetBuilder.TotalBytesCached >= packetBuilder.TotalBytesExpected)                {                    //Once we think we might have enough data we call the incoming packet handle handoff                    //Should we have a complete packet this method will start the appriate task                    //This method will now clear byes from the incoming packets if we have received something complete.                    //调用IncomingPacketHandleHandOff方法处理“数据包接收器”(packetBuilder)中已经接收到的字节数据，并把二进制数据还原成相应的类型，进行处理                    IncomingPacketHandleHandOff(packetBuilder);                }                if (totalBytesRead == 0 && (!dataAvailable || ConnectionInfo.ConnectionState == ConnectionState.Shutdown))                    CloseConnection(false, -2);                else                {                    //We need a buffer for our incoming data                    //First we try to reuse a previous buffer                    if (packetBuilder.TotalPartialPacketCount > 0 && packetBuilder.NumUnusedBytesMostRecentPartialPacket() > 0)                        dataBuffer = packetBuilder.RemoveMostRecentPartialPacket(ref totalBytesRead);                    else                    {                        //If we have nothing to reuse we al