【每日一博】用 libevent 改造 teamtalk 底层网络框架

因为之前群友对teamtalk的底层网络框架性能诸多抱怨,并且蓝狐大大也曾跟我说起过想用libevent重写底层网络框架,刚好最近我想用hiredis的异步连接客户端给teamtalk加我自己的功能,而hiredis的异步客户端只能适配libevent, libev, libuv等几个知名的异步框架。如果我想用只有两个办法,一,自己给hiredis新增一个teamtalk的异步网络适配器, 二, 用libevent或者libuv重写teamtalk底层网络框架。

想到改写teamtalk底层网络框架并非易事,有可能迁一发动全身,然后就玩大了,所以我就先去看了hiredis的源码,看了大半天结果发现还是回去改造teamtalk吧。。。

然后就开始在几个网络框架里选择用哪一个来改写,libev首先被剔除了,原因我就不讲了,你懂的。然后对我来讲,因为鄙人的node.js功力非常深厚,而libuv则是node.js的底层网络库,所以选择libuv自然应该是理所当然的了。然后就开始弄了,弄了老半天结果发现真的玩大了,至于为什么你可以去尝试一下,也许你可以的,我是放弃了,然后就还是libevent了。

“你这货废话怎么这么多!!!”

“因为其实我不是程序员,鄙人日常工作是拉皮条的。”

关于teamtalk的底层网络框架的性能问题,我这里先来举个例子做个说明

int netlib_send(net_handle_t handle, void* buf, int len) {  CBaseSocket* pSocket = FindBaseSocket(handle);  if (!pSocket)  {   return NETLIB_ERROR;  }  int ret = pSocket->Send(buf, len);  pSocket->ReleaseRef();  return ret; }

上面这段代码是teamtalk的原始netlib库的发送函数,所有功能要发送报文最终都会调到这个函数,然后你就可以看到了,这段函数每次发送数据前都要FindBaseSocket一把,当你的并发连接不多时这个查找倒也无所谓,但如果这时你有十万个并发连接,那么你每次哪怕是发一个小包包都要去这十万个basesocket里面找一把,这个就让人不那么爽了(尽管map查找似乎还挺快,然而也并没有什么软用)。

所以,如果你不爽,那就想办法让自己爽起来吧,人生苦短,请及时行乐。

怎么才能爽起来呢?必须把这里的find给弄掉,并且还不能碰netlib栈以上的代码,也就是说千万别去碰CImConn,如果你连那个也改了,相信我你肯定不会爽起来的。不知道CImConn的同学可以读一下我前面的博文。

所以,原则就定下来了,只能改动netlib内部的实现,不要变动其对外的接口,如果做到这一点,你最终只需要改动很少的代码并让自己爽起来。

“好了,今天就到此为止吧,该说的都讲清楚了,我特么真是个写博客的人才~”

”卧槽,你还没讲怎么改呢!@!“

”不是说了么,只改netlib内部实现,你就能嗨起来了。“

”擦!“

好吧,为了不被喷,我还是把我自己改的代码贡献出来吧

#include "netlib.h" #include "BaseSocket.h" #include "EventDispatch.h" #define __LIBEVENT__ #ifndef __LIBEVENT__ int netlib_init() {  int ret = NETLIB_OK; #ifdef _WIN32  WSADATA wsaData;  WORD wReqest = MAKEWORD(1, 1);  if (WSAStartup(wReqest, &wsaData) != 0)  {   ret = NETLIB_ERROR;  } #endif  return ret; } int netlib_destroy() {  int ret = NETLIB_OK; #ifdef _WIN32  if (WSACleanup() != 0)  {   ret = NETLIB_ERROR;  } #endif  return ret; } int netlib_listen(   const char* server_ip,    uint16_t port,   callback_t callback,   void*  callback_data) {  auto spSocket = sp_CBaseSocket(new CBaseSocket());  if (!spSocket)   return NETLIB_ERROR;  int ret =  spSocket->Listen(server_ip, port, callback, callback_data);  // if (ret == NETLIB_ERROR)  //  delete pSocket;  return ret; } net_handle_t netlib_connect(   const char* server_ip,    uint16_t port,    callback_t callback,    void*  callback_data) {  auto spSocket = sp_CBaseSocket(new CBaseSocket());  if (!spSocket)   return NETLIB_INVALID_HANDLE;  net_handle_t handle = spSocket->Connect(server_ip, port, callback, callback_data);  // if (handle == NETLIB_INVALID_HANDLE)  //  delete pSocket;  return handle; } int netlib_send(net_handle_t handle, void* buf, int len) {  auto spSocket = FindBaseSocket(handle);  if (!spSocket)  {   return NETLIB_ERROR;  }  int ret = spSocket->Send(buf, len);  // pSocket->ReleaseRef();  return ret; } int netlib_recv(net_handle_t handle, void* buf, int len) {  auto spSocket = FindBaseSocket(handle);  if (!spSocket)   return NETLIB_ERROR;  int ret = spSocket->Recv(buf, len);  // pSocket->ReleaseRef();  return ret; } int netlib_close(net_handle_t handle) {  auto spSocket = FindBaseSocket(handle);  if (!spSocket)   return NETLIB_ERROR;  int ret = spSocket->Close();  // pSocket->ReleaseRef();  return ret; } int netlib_option(net_handle_t handle, int opt, void* optval) {  auto spSocket = FindBaseSocket(handle);  if (!spSocket)   return NETLIB_ERROR;  if ((opt >= NETLIB_OPT_GET_REMOTE_IP) && !optval)   return NETLIB_ERROR;  switch (opt)  {  case NETLIB_OPT_SET_CALLBACK:   spSocket->SetCallback((callback_t)optval);   break;  case NETLIB_OPT_SET_CALLBACK_DATA:   spSocket->SetCallbackData(optval);   break;  case NETLIB_OPT_GET_REMOTE_IP:   *(string*)optval = spSocket->GetRemoteIP();   break;  case NETLIB_OPT_GET_REMOTE_PORT:   *(uint16_t*)optval = spSocket->GetRemotePort();   break;  case NETLIB_OPT_GET_LOCAL_IP:   *(string*)optval = spSocket->GetLocalIP();   break;  case NETLIB_OPT_GET_LOCAL_PORT:   *(uint16_t*)optval = spSocket->GetLocalPort();   break;  case NETLIB_OPT_SET_SEND_BUF_SIZE:   spSocket->SetSendBufSize(*(uint32_t*)optval);   break;  case NETLIB_OPT_SET_RECV_BUF_SIZE:   spSocket->SetRecvBufSize(*(uint32_t*)optval);   break;  }  // pSocket->ReleaseRef();  return NETLIB_OK; } int netlib_register_timer(callback_t callback, void* user_data, uint64_t interval) {  CEventDispatch::Instance()->AddTimer(callback, user_data, interval);  return 0; } int netlib_delete_timer(callback_t callback, void* user_data) {  CEventDispatch::Instance()->RemoveTimer(callback, user_data);  return 0; } int netlib_add_loop(callback_t callback, void* user_data) {  CEventDispatch::Instance()->AddLoop(callback, user_data);  return 0; } void netlib_eventloop(uint32_t wait_timeout) {  CEventDispatch::Instance()->StartDispatch(wait_timeout); } void netlib_stop_event() {  CEventDispatch::Instance()->StopDispatch(); } bool netlib_is_running() {  return CEventDispatch::Instance()->isRunning(); } #else #include  #include  static unordered_mapstruct event*> g_read_event_map; static unordered_map g_write_event_map; static unordered_map g_timer_map; struct event_base* g_libevent_base; static string _GetRemoteIP(net_handle_t hd); static uint16_t _GetRemotePort(net_handle_t hd); static string _GetLocalIP(net_handle_t hd); static uint16_t _GetLocalPort(net_handle_t hd); static void _SetSendBufSize(net_handle_t hd, uint32_t send_size); static void _SetRecvBufSize(net_handle_t hd, uint32_t recv_size); static int _GetErrorCode(); static void _SetNonblock(SOCKET fd); static bool _IsBlock(int error_code); static void _SetReuseAddr(SOCKET fd); static void _SetNoDelay(SOCKET fd); static void _SetAddr(const char* ip, const uint16_t port, sockaddr_in* pAddr); void netlib_onconfirm(evutil_socket_t fd, short what, void *arg); void netlib_onread(evutil_socket_t fd, short what, void *arg); void netlib_onwrite(evutil_socket_t fd, short what, void *arg); void netlib_onaccept(evutil_socket_t fd, short what, void *arg); void netlib_ontimer(evutil_socket_t fd, short what, void* arg); void netlib_check_write_error(net_handle_t fd, int* error, socklen_t* len); void netlib_set_onconnect_event(net_handle_t handle, callback_t callback, void* cbdata); struct EvtArg {  callback_t callback;  void* cbdata;  EvtArg(callback_t c, void* d) : callback(c), cbdata(d) {}  ~EvtArg() {} }; struct EvtArg2 {  callback_t callback;  void* cbdata;  struct event* evt;  EvtArg2(callback_t c, void* d, struct event* e) : callback(c), cbdata(d), evt(e) {}  ~EvtArg2() {} }; static int _GetErrorCode() { #ifdef _WIN32  return WSAGetLastError(); #else  return errno; #endif } static void _SetNonblock(SOCKET fd) { #ifdef _WIN32  u_long nonblock = 1;  int ret = ioctlsocket(fd, FIONBIO, &nonblock); #else  int ret = fcntl(fd, F_SETFL, O_NONBLOCK | fcntl(fd, F_GETFL)); #endif  if (ret == SOCKET_ERROR)  {   log("_SetNonblock failed, err_code=%d", _GetErrorCode());  } } static bool _IsBlock(int error_code) { #ifdef _WIN32  return ( (error_code == WSAEINPROGRESS) || (error_code == WSAEWOULDBLOCK) ); #else  return ( (error_code == EINPROGRESS) || (error_code == EWOULDBLOCK) ); #endif } static void _SetReuseAddr(SOCKET fd) {  int reuse = 1;  int ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char*)&reuse, sizeof(reuse));  if (ret == SOCKET_ERROR)  {   log("_SetReuseAddr failed, err_code=%d", _GetErrorCode());  } } static void _SetNoDelay(SOCKET fd) {  int nodelay = 1;  int ret = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char*)&nodelay, sizeof(nodelay));  if (ret == SOCKET_ERROR)  {   log("_SetNoDelay failed, err_code=%d", _GetErrorCode());  } } static void _SetAddr(const char* ip, const uint16_t port, sockaddr_in* pAddr) {  memset(pAddr, 0, sizeof(sockaddr_in));  pAddr->sin_family = AF_INET;  pAddr->sin_port = htons(port);  pAddr->sin_addr.s_addr = inet_addr(ip);  if (pAddr->sin_addr.s_addr == INADDR_NONE)  {   hostent* host = gethostbyname(ip);   if (host == NULL)   {    log("gethostbyname failed, ip=%s", ip);    return;   }   pAddr->sin_addr.s_addr = *(uint32_t*)host->h_addr;  } } int netlib_init() {  int ret = NETLIB_OK; #ifdef _WIN32  WSADATA wsaData;  WORD wReqest = MAKEWORD(1, 1);  if (WSAStartup(wReqest, &wsaData) != 0) {   ret = NETLIB_ERROR;  } #endif  g_libevent_base = event_base_new();  return ret; } int netlib_destroy() {  int ret = NETLIB_OK; #ifdef _WIN32  if (WSACleanup() != 0) {   ret = NETLIB_ERROR;  } #endif  event_base_free(g_libevent_base);  return ret; } net_handle_t netlib_connect(   const char* server_ip,    uint16_t port,    callback_t callback,    void*  callback_data) {  net_handle_t sock = socket(AF_INET, SOCK_STREAM, 0);  if (sock == INVALID_SOCKET) {   loge("socket failed, err_code=%d", _GetErrorCode());   return NETLIB_INVALID_HANDLE;  }  _SetNonblock(sock);  _SetNoDelay(sock);  sockaddr_in serv_addr;  _SetAddr(server_ip, port, &serv_addr);  int ret = connect(sock, (sockaddr*)&serv_addr, sizeof(serv_addr));  if ( (ret == SOCKET_ERROR) && (!_IsBlock(_GetErrorCode())) ) {   loge("connect failed, err_code=%d", _GetErrorCode());   closesocket(sock);   return NETLIB_INVALID_HANDLE;  }  auto evtArg2 = new EvtArg2(callback, callback_data, NULL);  evtArg2->evt = event_new(g_libevent_base, sock, EV_WRITE, netlib_onconfirm, evtArg2);  event_add(evtArg2->evt, NULL);  return sock; } int netlib_close(net_handle_t handle) {  auto it = g_read_event_map.find(handle);  if (it != g_read_event_map.end()) {   auto ev = it->second;   g_read_event_map.erase(it);   event_free(ev);  }  auto it2 = g_write_event_map.find(handle);  if (it2 != g_write_event_map.end()) {   auto ev = it2->second;   g_write_event_map.erase(it2);   event_free(ev);  }  closesocket(handle);  return 0; } int netlib_listen(   const char* server_ip,    uint16_t port,   callback_t callback,   void*  callback_data) {  auto sock = socket(AF_INET, SOCK_STREAM, 0);  if (sock == INVALID_SOCKET) {   printf("socket failed, err_code=%d/n", _GetErrorCode());   return NETLIB_ERROR;  }  _SetReuseAddr(sock);  _SetNonblock(sock);  sockaddr_in serv_addr;  _SetAddr(server_ip, port, &serv_addr);  int ret = bind(sock, (sockaddr*)&serv_addr, sizeof(serv_addr));  if (ret == SOCKET_ERROR) {   loge("bind failed, err_code=%d", _GetErrorCode());   closesocket(sock);   return NETLIB_ERROR;  }  ret = listen(sock, 64);  if (ret == SOCKET_ERROR) {   loge("listen failed, err_code=%d", _GetErrorCode());   closesocket(sock);   return NETLIB_ERROR;  }  auto evtArg = new EvtArg(callback, callback_data);  struct event* ev = event_new(g_libevent_base, sock, EV_READ|EV_PERSIST, netlib_onaccept, evtArg);  event_add(ev, NULL);  return NETLIB_OK; } void netlib_onaccept(evutil_socket_t fd, short what, void *arg) {  sockaddr_in peer_addr;  socklen_t addr_len = sizeof(sockaddr_in);  char ip_str[64];  while ( (fd = accept(fd, (sockaddr*)&peer_addr, &addr_len)) != INVALID_SOCKET )  {   _SetNoDelay(fd);   _SetNonblock(fd);   auto evtArg = (EvtArg*)arg;   evtArg->callback(evtArg->cbdata, NETLIB_MSG_CONNECT, (net_handle_t)fd, NULL);  }  } void netlib_check_write_error(net_handle_t fd, int* error, socklen_t* len) { #ifdef _WIN32  getsockopt(fd, SOL_SOCKET, SO_ERROR, (char*)error, len); #else  getsockopt(fd, SOL_SOCKET, SO_ERROR, (void*)error, len); #endif  } void netlib_onconfirm(evutil_socket_t fd, short what, void *arg) {  auto evtArg2 = (EvtArg2*)arg;  int error = 0;  socklen_t len = sizeof(error);  netlib_check_write_error((net_handle_t)fd, &error, &len);  if (error) {   evtArg2->callback(evtArg2->cbdata, NETLIB_MSG_CLOSE, (net_handle_t)fd, NULL);  } else {   event_free(evtArg2->evt);   auto arg = new EvtArg(evtArg2->callback, evtArg2->cbdata);   struct event* evread = event_new(g_libevent_base, fd, EV_READ|EV_PERSIST|EV_ET, netlib_onread, arg);   struct event* evwrite = event_new(g_libevent_base, fd, EV_WRITE|EV_PERSIST|EV_ET, netlib_onwrite, arg);   event_add(evread, NULL);   event_add(evwrite, NULL);   g_read_event_map[fd] = evread;   g_write_event_map[fd] = evwrite;   evtArg2->callback(evtArg2->cbdata, NETLIB_MSG_CONFIRM, (net_handle_t)fd, NULL);  } } void netlib_onread(evutil_socket_t fd, short what, void *arg) {  auto evtArg = (EvtArg*)arg;  evtArg->callback(evtArg->cbdata, NETLIB_MSG_READ, (net_handle_t)fd, NULL); } void netlib_onwrite(evutil_socket_t fd, short what, void *arg) {  auto evtArg = (EvtArg*)arg;  evtArg->callback(evtArg->cbdata, NETLIB_MSG_WRITE, (net_handle_t)fd, NULL); } void netlib_set_onconnect_event(net_handle_t handle, callback_t callback, void* cbdata) {  auto arg = new EvtArg(callback, cbdata);  struct event* evread = event_new(g_libevent_base, handle, EV_READ|EV_PERSIST|EV_ET, netlib_onread, arg);  struct event* evwrite = event_new(g_libevent_base, handle, EV_WRITE|EV_PERSIST|EV_ET, netlib_onwrite, arg);  event_add(evread, NULL);  event_add(evwrite, NULL);  g_read_event_map[handle] = evread;  g_write_event_map[handle] = evwrite; } string _GetRemoteIP(net_handle_t hd) {  struct sockaddr_in sa;  socklen_t len = sizeof(sa);  if (!getpeername(hd, (struct sockaddr*)&sa, &len)) {   return inet_ntoa(sa.sin_addr);  } else {   return "";  } } uint16_t _GetRemotePort(net_handle_t hd) {  struct sockaddr_in sa;  socklen_t len = sizeof(sa);  if (!getpeername(hd, (struct sockaddr*)&sa, &len)) {   return ntohs(sa.sin_port);  } else {   return 0;  }  } string _GetLocalIP(net_handle_t hd) {  struct sockaddr_in sa;  socklen_t len = sizeof(sa);  if (!getsockname(hd, (struct sockaddr*)&sa, &len)) {   return inet_ntoa(sa.sin_addr);  } else {   return "";  }  } uint16_t _GetLocalPort(net_handle_t hd) {  struct sockaddr_in sa;  socklen_t len = sizeof(sa);  if (!getsockname(hd, (struct sockaddr*)&sa, &len)) {   return ntohs(sa.sin_port);  } else {   return 0;  }  } void _SetSendBufSize(net_handle_t hd, uint32_t send_size) {  int ret = setsockopt(hd, SOL_SOCKET, SO_SNDBUF, &send_size, 4);  if (ret == SOCKET_ERROR) {   loge("set SO_SNDBUF failed for fd=%d", hd);  }  socklen_t len = 4;  int size = 0;  getsockopt(hd, SOL_SOCKET, SO_SNDBUF, &size, &len);  loge("socket=%d send_buf_size=%d", hd, size);  } void _SetRecvBufSize(net_handle_t hd, uint32_t recv_size) {  int ret = setsockopt(hd, SOL_SOCKET, SO_RCVBUF, &recv_size, 4);  if (ret == SOCKET_ERROR) {   loge("set SO_RCVBUF failed for fd=%d", hd);  }  socklen_t len = 4;  int size = 0;  getsockopt(hd, SOL_SOCKET, SO_RCVBUF, &size, &len);  loge("socket=%d recv_buf_size=%d", hd, size);  } int netlib_option(net_handle_t handle, int opt, void* optval) {  static callback_t cb;  if ((opt >= NETLIB_OPT_GET_REMOTE_IP) && !optval)   return NETLIB_ERROR;  switch (opt) {   case NETLIB_OPT_SET_CALLBACK:    cb = (callback_t)optval;    break;   case NETLIB_OPT_SET_CALLBACK_DATA:    netlib_set_onconnect_event(handle, cb, optval);    break;   case NETLIB_OPT_GET_REMOTE_IP:    *(string*)optval = _GetRemoteIP(handle);    break;   case NETLIB_OPT_GET_REMOTE_PORT:    *(uint16_t*)optval = _GetRemotePort(handle);    break;   case NETLIB_OPT_GET_LOCAL_IP:    *(string*)optval = _GetLocalIP(handle);    break;   case NETLIB_OPT_GET_LOCAL_PORT:    *(uint16_t*)optval = _GetLocalPort(handle);    break;   case NETLIB_OPT_SET_SEND_BUF_SIZE:    _SetSendBufSize(handle, *(uint32_t*)optval);    break;   case NETLIB_OPT_SET_RECV_BUF_SIZE:    _SetRecvBufSize(handle, *(uint32_t*)optval);    break;   default:    break;  }  return NETLIB_OK; } int netlib_send(net_handle_t handle, void* buf, int len) {  return send(handle, (char*)buf, len, 0); } int netlib_recv(net_handle_t handle, void* buf, int len) {  return recv(handle, (char*)buf, len, 0); } int netlib_register_timer(callback_t callback, void* user_data, uint64_t interval) {  long int sec = interval/1000L;  long int usec = interval%1000L;  struct timeval t = {sec, usec};  auto arg = new EvtArg(callback, user_data);  struct event* ev = event_new(g_libevent_base, -1, EV_PERSIST, netlib_ontimer, arg);  event_add(ev, &t);  g_timer_map[callback] = ev;  return 0; } int netlib_delete_timer(callback_t callback, void* user_data) {  auto it = g_timer_map.find(callback);  if (it != g_timer_map.end()) {   auto ev = it->second;   g_timer_map.erase(it);   event_free(ev);  }  return 0; } void netlib_ontimer(evutil_socket_t fd, short what, void* arg) {  EvtArg* evtArg = (EvtArg*)arg;  evtArg->callback(evtArg->cbdata, NETLIB_MSG_TIMER, 0, NULL); } int netlib_add_loop(callback_t callback, void* user_data) {  struct timeval t = {0, 100};  auto arg = new EvtArg(callback, user_data);  struct event* ev = event_new(g_libevent_base, -1, EV_PERSIST, netlib_ontimer, arg);  event_add(ev, &t);  // g_timer_map[callback] = ev;  return 0; } void netlib_eventloop(uint32_t wait_timeout) {  event_base_dispatch(g_libevent_base); } void netlib_stop_event() {  event_base_loopbreak(g_libevent_base); } bool netlib_is_running() {  bool ret = !event_base_got_break(g_libevent_base);  return ret; } #endif 

上面的代码用了宏控制选择编译老的netlib库还是新的被libevent修改的库,老的库可能跟你的也略有不同,因为我用了c++11的智能指针改造了一下。代码没有注释,如果你对libevent和socket挺熟悉的话我相信能很快看懂的,如果不熟,那就直接替换你的netlib.cpp吧,我自己已经自测过没有问题,.h头文件不需要修改。

另外还有个地方需要说明一下,我把原来BaseSocket.cpp里面的OnRead和OnWrite里的出错检查给去掉了,因为我觉得也让我不爽,也就是下面这两段代码,并且把连接事件明确的和onaccept以及onconfirm对应起来,所以不再需要在onread和onwrite里来判断当前socket状态是listening还是connecting来选择accept和confirm了

u_long avail = 0;   if ( (ioctlsocket(m_socket, FIONREAD, &avail) == SOCKET_ERROR) || (avail == 0) )   {    m_callback(m_callback_data, NETLIB_MSG_CLOSE, (net_handle_t)m_socket, NULL);   }
#if ((defined _WIN32) || (defined __APPLE__))  CEventDispatch::Instance()->RemoveEvent(m_socket, SOCKET_WRITE); #endif   if (m_state == SOCKET_STATE_CONNECTING)  {   int error = 0;   socklen_t len = sizeof(error); #ifdef _WIN32    getsockopt(m_socket, SOL_SOCKET, SO_ERROR, (char*)&error, &len); #else   getsockopt(m_socket, SOL_SOCKET, SO_ERROR, (void*)&error, &len); #endif   if (error) {    m_callback(m_callback_data, NETLIB_MSG_CLOSE, (net_handle_t)m_socket, NULL);   } else {    m_state = SOCKET_STATE_CONNECTED;

那么对于socket读写异常的判断在哪里做的呢?答案是交给netlib的调用者做。

”卧槽,你不是说不要碰netlib上层的代码吗!?“

”但是我还是碰了,因为不碰不能爽。。“

请自己搜一下你代码里调用netlib_recv和netlib_send的地方,然后略作如下修改

void CImConn::OnRead() {  for (;;)  {   uint32_t free_buf_len = m_in_buf.GetAllocSize() - m_in_buf.GetWriteOffset();   if (free_buf_len < READ_BUF_SIZE)    m_in_buf.Extend(READ_BUF_SIZE);    int ret = netlib_recv(m_handle, m_in_buf.GetBuffer() + m_in_buf.GetWriteOffset(), READ_BUF_SIZE);   if (ret == 0) {    log("close on netlib_recv=0");    OnClose();    return;   } else if (ret < 0) {    if (errno == EAGAIN || errno == EWOULDBLOCK) {     break;    } else {     log("close on error=%d", errno);     OnClose();     return;    }   }
void CImConn::OnWrite() {  // CAutoLock autoLock(&s_send_lock);  if (!m_busy)   return;   while (m_out_buf.GetWriteOffset() > 0) {   int send_size = m_out_buf.GetWriteOffset();   if (send_size > NETLIB_MAX_SOCKET_BUF_SIZE) {    send_size = NETLIB_MAX_SOCKET_BUF_SIZE;   }    int ret = netlib_send(m_handle, m_out_buf.GetBuffer(), send_size);   if (ret <= 0) {    if (errno == EAGAIN || errno == EWOULDBLOCK) {     break;    } else {     log("close on error=%d", errno);     OnClose();     return;    }   }

好了,就到这里了,未来如果我发现改动有什么bug的话,我会更新这篇博文,请关注我即可。

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转载请注明原文出处:Harries Blog? ? 【每日一博】用 libevent 改造 teamtalk 底层网络框架

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