本文基于networkcomms2.3.1开源版本 gplv3协议
在networkcomms通信系统中，服务器端收到某连接上的数据后，数据会暂时存放在"数据包创建器"(PacketBuilder)中,PacketBuilder类似一个流动的容器，收到的数据被服务器处理完成后，相应在二进制数据，会从存储他的PacketBuilder中删除。
我们知道在networkcomms的消息体系中，传送的数据的第一个字节用来存储数据包包头长度，解析出数据包包头后，包头中包含数据包长度。所以在读入进入PacketBuilder中的数据，会根据第一个字节中存储的数据，解析出包头的长度，进一步解析出数据包的长度。如果PacketBuilder中的存储的字节大小，大于数据包的长度，那么主程序将会对PacketBuilder中的数据，进行提取，并进行处理。
此节，我们暂时不讨论PacketBuilder的细节，先看一下服务器如何对PacketBuilder中的数据进行处理
protected void IncomingPacketHandleHandOff(PacketBuilder packetBuilder) { try { if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... checking for completed packet with " + packetBuilder.TotalBytesCached.ToString() + " bytes read."); if (packetBuilder.TotalPartialPacketCount == 0) throw new Exception("Executing IncomingPacketHandleHandOff when no packets exist in packetbuilder."); //循环，直到我们完成对packetBuilder的处理 //Loop until we are finished with this packetBuilder int loopCounter = 0; while (true) { //If we have ended up with a null packet at the front, probably due to some form of concatentation we can pull it off here //It is possible we have concatenation of several null packets along with real data so we loop until the firstByte is greater than 0 //此处，可能是处理心跳检测时对方发来的0字节数据 if (packetBuilder.FirstByte() == 0) { if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... null packet removed in IncomingPacketHandleHandOff() from " + ConnectionInfo + ", loop index - " + loopCounter.ToString()); packetBuilder.ClearNTopBytes(1); //Reset the expected bytes to 0 so that the next check starts from scratch packetBuilder.TotalBytesExpected = 0; //If we have run out of data completely then we can return immediately if (packetBuilder.TotalBytesCached == 0) return; } else { //First determine the expected size of a header packet //获取数据包包头长度 int packetHeaderSize = packetBuilder.FirstByte() + 1; //Do we have enough data to build a header? //如果没有足够的二级制数据来还原出一个数据包包头 if (packetBuilder.TotalBytesCached < packetHeaderSize) { if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... ... more data required for complete packet header."); //Set the expected number of bytes and then return packetBuilder.TotalBytesExpected = packetHeaderSize; return; } //We have enough for a header //有足够的数据来还原出数据包包头 PacketHeader topPacketHeader; using(MemoryStream headerStream = packetBuilder.ReadDataSection(1, packetHeaderSize - 1)) //数据包包头 topPacketHeader = new PacketHeader(headerStream, NetworkComms.InternalFixedSendReceiveOptions); //Idiot test if (topPacketHeader.PacketType == null) throw new SerialisationException("packetType value in packetHeader should never be null"); //We can now use the header to establish if we have enough payload data //First case is when we have not yet received enough data //如果没有足够的数据来还原出数据包 if (packetBuilder.TotalBytesCached < packetHeaderSize + topPacketHeader.PayloadPacketSize) { if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... ... more data required for complete packet payload. Expecting " + (packetHeaderSize + topPacketHeader.PayloadPacketSize).ToString() + " total packet bytes."); //Set the expected number of bytes and then return packetBuilder.TotalBytesExpected = packetHeaderSize + topPacketHeader.PayloadPacketSize; return; } //Second case is we have enough data //有足够的数据还原出数据包 else if (packetBuilder.TotalBytesCached >= packetHeaderSize + topPacketHeader.PayloadPacketSize) { //We can either have exactly the right amount or even more than we were expecting //We may have too much data if we are sending high quantities and the packets have been concatenated //no problem!! SendReceiveOptions incomingPacketSendReceiveOptions = IncomingPacketSendReceiveOptions(topPacketHeader); if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Debug("Received packet of type '" + topPacketHeader.PacketType + "' from " + ConnectionInfo + ", containing " + packetHeaderSize.ToString() + " header bytes and " + topPacketHeader.PayloadPacketSize.ToString() + " payload bytes."); //If this is a reserved packetType we call the method inline so that it gets dealt with immediately //判断是否为保留类型，保留类型会优先处理 //保留类型包括心跳检测、连接建立等 bool isReservedType = false; foreach (var tName in NetworkComms.reservedPacketTypeNames) { //isReservedType |= topPacketHeader.PacketType == tName; if (topPacketHeader.PacketType == tName) { isReservedType = true; break; } } //Only reserved packet types get completed inline //如果数据包类型为保留类型 设定为高优先级 if (isReservedType) {#if WINDOWS_PHONE var priority = QueueItemPriority.Normal;#else var priority = (QueueItemPriority)Thread.CurrentThread.Priority;#endif //创建优先级队列项目 PriorityQueueItem item = new PriorityQueueItem(priority, this, topPacketHeader, packetBuilder.ReadDataSection(packetHeaderSize, topPacketHeader.PayloadPacketSize), incomingPacketSendReceiveOptions); if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... handling packet type '" + topPacketHeader.PacketType + "' inline. Loop index - " + loopCounter.ToString()); NetworkComms.CompleteIncomingItemTask(item); } else { //创建优先级队列项目 QueueItemPriority itemPriority = (incomingPacketSendReceiveOptions.Options.ContainsKey("ReceiveHandlePriority") ? (QueueItemPriority)Enum.Parse(typeof(QueueItemPriority), incomingPacketSendReceiveOptions.Options["ReceiveHandlePriority"]) : QueueItemPriority.Normal); //把数据包包头，和数据包数据 赋值给优先级队列项 PriorityQueueItem item = new PriorityQueueItem(itemPriority, this, topPacketHeader, packetBuilder.ReadDataSection(packetHeaderSize, topPacketHeader.PayloadPacketSize), incomingPacketSendReceiveOptions); //QueueItemPriority.Highest is the only priority that is executed inline#if !WINDOWS_PHONE //如果是最高优先级，当前线程处理 if (itemPriority == QueueItemPriority.Highest) { if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... handling packet type '" + topPacketHeader.PacketType + "' with priority HIGHEST inline. Loop index - " + loopCounter.ToString()); NetworkComms.CompleteIncomingItemTask(item); } else { //不是最高优先级 交给自定义线程池处理 此线程池支持优先级处理 int threadId = NetworkComms.CommsThreadPool.EnqueueItem(item.Priority, NetworkComms.CompleteIncomingItemTask, item); if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... added completed " + item.PacketHeader.PacketType + " packet to thread pool (Q:" + NetworkComms.CommsThreadPool.QueueCount.ToString() + ", T:" + NetworkComms.CommsThreadPool.CurrentNumTotalThreads.ToString() + ", I:" + NetworkComms.CommsThreadPool.CurrentNumIdleThreads.ToString() + ") with priority " + itemPriority.ToString() + (threadId > 0 ? ". Selected threadId=" + threadId.ToString() : "") + ". Loop index=" + loopCounter.ToString() + "."); }#else int threadId = NetworkComms.CommsThreadPool.EnqueueItem(item.Priority, NetworkComms.CompleteIncomingItemTask, item); if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... added completed " + item.PacketHeader.PacketType + " packet to thread pool (Q:" + NetworkComms.CommsThreadPool.QueueCount.ToString() + ", T:" + NetworkComms.CommsThreadPool.CurrentNumTotalThreads.ToString() + ", I:" + NetworkComms.CommsThreadPool.CurrentNumIdleThreads.ToString() + ") with priority " + itemPriority.ToString() + (threadId > 0 ? ". Selected threadId=" + threadId.ToString() : "") + ". Loop index=" + loopCounter.ToString() + ".");#endif } //从PacketBuilder中删除已经处理过的数据 //We clear the bytes we have just handed off if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Removing " + (packetHeaderSize + topPacketHeader.PayloadPacketSize).ToString() + " bytes from incoming packet buffer from connection with " + ConnectionInfo +"."); packetBuilder.ClearNTopBytes(packetHeaderSize + topPacketHeader.PayloadPacketSize); //Reset the expected bytes to 0 so that the next check starts from scratch packetBuilder.TotalBytesExpected = 0; //If we have run out of data completely then we can return immediately if (packetBuilder.TotalBytesCached == 0) return; } else throw new CommunicationException("This should be impossible!"); } loopCounter++; } } catch (Exception ex) { //Any error, throw an exception. if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Fatal("A fatal exception occured in IncomingPacketHandleHandOff(), connection with " + ConnectionInfo + " be closed. See log file for more information."); NetworkComms.LogError(ex, "CommsError"); CloseConnection(true, 45); } }
在上面的数据处理过程中，不知道您是否注意到一个重要的概念，即“自定义线程池”，
CommsThreadPool此线程池，可以说是Networkcomms通信框架中一颗璀璨的明珠，由他负责处理接收到的所有数据，此线程池支持优先级，即高优先级的数据会被优先处理www.networkcomms.cnwww.cnblogs.com/networkcomms