MMORPG大型游戏设计与开发（part3 of net）

　　这一部分需要向大家介绍的是服务器的select以及收发包的具体流程，从核心代码功能上分析网络交互具体过程。

　　首先大家要看第二部分（part2 of net）的代码结构图，因为在接下来的流程过程中会用到其中模块的名称，若是不知道大致的功能那么接下来的解说可能就成为天书了。

　　总体流程为：服务器管理器初始化并创建主套接字连接，进入主循环等待新连接（select），如果有新的连接则将新连接加入连接管理器。不管有没有新的连接，循环会依次处理连接的异常->输入流->输出流->命令处理。其中异常即连接包发送错误的处理，输入流即套接字输入流中如果大小长度不为空则重新拼接包，输出流进行包的拼接，并将未发送的流进行发送，命令处理其实是对输入流的处理，处理（handler）发送过来的包。

　　以下详细说明这几个流程从代码上的实现，以及所在的模块。

　　1、  服务器管理器初始化（servermanager）

bool ServerManager::init() {

  __ENTER_FUNCTION

    serversocket_ = 

      new pap_server_common_net::Socket(g_config.billing_info_.port_);

    Assert(serversocket_);

    serversocket_->set_nonblocking();

    socketid_ = serversocket_->getid();

    Assert(socketid_ != SOCKET_INVALID);

    FD_SET(socketid_, &readfds_[kSelectFull]);

    FD_SET(socketid_, &exceptfds_[kSelectFull]);

    minfd_ = maxfd_ = socketid_;

    timeout_[kSelectFull].tv_sec = 0;

    timeout_[kSelectFull].tv_usec = 0;

    threadid_ = pap_common_sys::get_current_thread_id();

    uint16_t i;

    for (i = 0; i < OVER_SERVER_MAX; ++i) {

      serverhash_[i] = ID_INVALID;

    }

    return true;

  __LEAVE_FUNCTION

    return false;

}

　　2、  服务器管理器进入主循环（servermanager）

 

void ServerManager::loop() {

  __ENTER_FUNCTION

    while (isactive()) {

      bool result = false;

      try {

        result = select();

        Assert(result);

        //ERRORPRINTF("select");

        result = processexception();

        Assert(result);

        //ERRORPRINTF("processexception");

        result = processinput();

        Assert(result);

        //ERRORPRINTF("processinput");

        result = processoutput();

        Assert(result); 

        //ERRORPRINTF("processoutput");

      }

      catch(...) {

        

      }

      try {

        result = processcommand();

        Assert(result);

        //ERRORPRINTF("processcommand");

      }

      catch(...) {

        

      }



      try {

        result = heartbeat();

        Assert(result);

      }

      catch(...) {

      }

    }

  __LEAVE_FUNCTION

}

loop

 

　　3、  服务器线程进入select模式

 

bool ServerManager::select() {

  __ENTER_FUNCTION

    timeout_[kSelectUse].tv_sec = timeout_[kSelectFull].tv_sec;

    timeout_[kSelectUse].tv_usec = timeout_[kSelectFull].tv_usec;

    readfds_[kSelectUse] = readfds_[kSelectFull];

    writefds_[kSelectUse] = writefds_[kSelectFull];

    exceptfds_[kSelectUse] = exceptfds_[kSelectFull];

    pap_common_base::util::sleep(100);

    int32_t result = SOCKET_ERROR;

    try {

      result = pap_common_net::socket::Base::select(

          maxfd_ + 1,

          &readfds_[kSelectUse],

          &writefds_[kSelectUse],

          &exceptfds_[kSelectUse],

          &timeout_[kSelectUse]);

      Assert(result != SOCKET_ERROR);

    }

    catch(...) {

      g_log->fast_save_log(kBillingLogFile, 

                           "ServerManager::select have error, result: %d", 

                           result);

    }

    return true;

  __LEAVE_FUNCTION

    return false;

}

select

 

　　4、  服务器线程进行异常处理

 

bool ServerManager::processexception() {

  __ENTER_FUNCTION

    if (SOCKET_INVALID == minfd_ && SOCKET_INVALID == maxfd_)

      return true;

    uint16_t connectioncount = billingconnection::Manager::getcount();

    billingconnection::Server* serverconnection = NULL;

    uint16_t i;

    for (i = 0; i < connectioncount; ++i) {

      if (ID_INVALID == connectionids_[i]) continue;

      serverconnection = g_connectionpool->get(connectionids_[i]);

      Assert(serverconnection);

      int32_t socketid = serverconnection->getsocket()->getid();

      if (socketid_ == socketid) {

        Assert(false);

        continue;

      }

      if (FD_ISSET(socketid, &exceptfds_[kSelectUse])) {

        removeconnection(serverconnection);

      }

    }

    return true;

  __LEAVE_FUNCTION

    return false;

}

processexception

 

　　5、  服务器线程进行输入流处理

 

bool ServerManager::processinput() {

  __ENTER_FUNCTION

    if (SOCKET_INVALID == minfd_ && SOCKET_INVALID == maxfd_)

      return true; //no connection

    uint16_t i;

    if (FD_ISSET(socketid_, &readfds_[kSelectUse])) {

      for (i = 0; i < kOneStepAccept; ++i) {

        if (!accept_newconnection()) break;

      }

    }

    uint16_t connectioncount = billingconnection::Manager::getcount();

    for (i = 0; i < connectioncount; ++i) {

      if (ID_INVALID == connectionids_[i]) continue;

      billingconnection::Server* serverconnection = NULL;

      serverconnection = g_connectionpool->get(connectionids_[i]);

      Assert(serverconnection);

      int32_t socketid = serverconnection->getsocket()->getid();

      if (socketid_ == socketid) continue;

      if (FD_ISSET(socketid, &readfds_[kSelectUse])) { //read information

        if (serverconnection->getsocket()->iserror()) {

          removeconnection(serverconnection);

        }

        else {

          try {

            if (!serverconnection->processinput()) 

              removeconnection(serverconnection);

          }

          catch(...) {

            removeconnection(serverconnection);

          }

        }

      }

    }

    return true;

  __LEAVE_FUNCTION

    return false;

}

processinput

 

　　6、  服务器线程进行输出流处理

 

bool ServerManager::processoutput() {

  __ENTER_FUNCTION

    if (SOCKET_INVALID == maxfd_&& SOCKET_INVALID == minfd_)

      return false;

    uint16_t i;

    uint16_t connectioncount = billingconnection::Manager::getcount();

    for (i = 0; i < connectioncount; ++i) {

      if (ID_INVALID == connectionids_[i]) continue;

      billingconnection::Server* serverconnection = NULL;

      serverconnection = g_connectionpool->get(connectionids_[i]);

      Assert(serverconnection);

      int32_t socketid = serverconnection->getsocket()->getid();

      if (socketid_ == socketid) continue;

      if (FD_ISSET(socketid, &writefds_[kSelectUse])) {

        if (serverconnection->getsocket()->iserror()) {

          removeconnection(serverconnection);

        }

        else {

          try {

            if (!serverconnection->processoutput()) 

              removeconnection(serverconnection);

          }

          catch(...) {

            removeconnection(serverconnection);

          }

        }

      }

    }

    return true;

  __LEAVE_FUNCTION

    return false;

}

processoutput

 

　　7、  服务器线程进行命令处理

bool ServerManager::processcommand() {

  __ENTER_FUNCTION

    if (SOCKET_INVALID == maxfd_&& SOCKET_INVALID == minfd_)

      return false;

    uint16_t i;

    uint16_t connectioncount = billingconnection::Manager::getcount();

    for (i = 0; i < connectioncount; ++i) {

      if (ID_INVALID == connectionids_[i]) continue;

      billingconnection::Server* serverconnection = NULL;

      serverconnection = g_connectionpool->get(connectionids_[i]);

      //serverconnection = &billing_serverconnection_;

      Assert(serverconnection);

      int32_t socketid = serverconnection->getsocket()->getid();

      if (socketid_ == socketid) continue;

      if (serverconnection->getsocket()->iserror()) {

        removeconnection(serverconnection);

      }

      else { //connection is ok

        try {

          if (!serverconnection->processcommand(false)) 

            removeconnection(serverconnection);

        }

        catch(...) {

          removeconnection(serverconnection);

        }

      }

    }

    return true;

  __LEAVE_FUNCTION

    return false;

}

processcommand

 

　　下一部分，我将讲解在网络部分一些重要的代码块。