关于连接状态改变的情况
客户端下线的两种方式
1.客户端主动下线
子线程会收到socket状态改变的消息
/* 连接状态改变 */
static void conn_eventcb(struct bufferevent *bev, short events, void *user_data)
{
auto c2 = (Channel2*)user_data;
auto c = c2->channel;
if(c->m_is_disconnected)
{
int a = 0;
return ;
}
static int offline = 0;
if((events & BEV_EVENT_EOF) || (events & BEV_EVENT_ERROR))
{
{ //如果已经下线，即不用做下线处理
std::lock_guard<std::mutex> lock(c2->ser->m_lts_mtx);
if(!c2->ser->m_allChannels[c->m_id])
return;
}
//printf("Connection closed.\n"); //BEV_EVENT_EOF
printf("Got an error on the connection: %s channel_id = %d, offline = %d, wait_offline = %d\n",
strerror(errno), c->m_id, ++offline, c2->ser->m_offline_que.size());/*XXX win32*/
{
c->m_is_disconnected = true;
c->m_event->on_stat_change(c->m_id, link_stat::link_disconnected);
}
{
auto ser = c2->ser;
LibEvtServer::OffChannel2 offc2 = { GetTickCount(), bev->ev_read.ev_fd, c2};
{//防止libevent thread 和 主线程(send_data)同时访问m_offline_que。
std::lock_guard<std::mutex> lock(ser->m_offline_mtx);
ser->m_offline_que.push(offc2);
#ifdef MUL_LIBEVENT_THREAD
}
{//防止多个libevent thread 线程同时访问下面公共变量
std::lock_guard<std::mutex> lock(ser->m_lts_mtx);
#endif
ser->m_allChannels[c->m_id] = NULL;
ser->m_ids->freeId(c->m_id);//[L]将id归还。
}
//int read_fd = bev->ev_read.ev_fd;
//int write_fd = bev->ev_write.ev_fd;
}
}
/* None of the other events can happen here, since we haven't enabled
* timeouts */
}
2.踢下线
bool LibEvtServer::close_channel(int channel_id)
{
auto c2 = m_allChannels[channel_id];
if(!c2->channel || c2->channel->m_is_disconnected)
return false;
auto c = c2->channel;
LibEvtServer::OffChannel2 offc2 = { GetTickCount(), c->m_bev->ev_read.ev_fd, c2};
{
std::lock_guard<std::mutex> lock(m_offline_mtx);
m_offline_que.push(offc2);//他也是将其push到这个下线队列中
#ifdef MUL_LIBEVENT_THREAD
}
{//防止多个libevent thread 线程同时访问下面公共变量
std::lock_guard<std::mutex> lock(m_lts_mtx);
#endif
m_allChannels[c->m_id] = NULL;
m_ids->freeId(c->m_id);//[L]将id归还。
}
return true;
}
在主线程中是什么时候关闭套接字的呢
在包发送超过100个的时候执行一次下线
bool LibEvtServer::free_one_link()
{
/**
*①让主线程来决定连接，为了保证bufferevent_write的第一个参数绝对有效；
*②一次处理一个，保证实时性。
*/
if(m_offline_que.size())
{
OffChannel2* offc2 = NULL;
{
std::lock_guard<std::mutex> lock(m_offline_mtx);
offc2 = &(m_offline_que.front());//注意需要用成员的引用或地址
}
if(offc2->c2)
{
delete offc2->c2->channel;//bufferevent_free(...)
delete offc2->c2;
offc2->c2 = nullptr;
}
if((GetTickCount() - offc2->offtime) > 60*1000)//延时60秒关闭套接字，保证工作线程调完套接字操作
{
evutil_closesocket(offc2->sockfd); //跨平台关闭套接字函数：Linux - close(fd); Windows - closesocket(fd)
std::lock_guard<std::mutex> lock(m_offline_mtx);
m_offline_que.pop();
}
}
return false;
}
注意这个写直接是主线程在写，读是在线程，释放连接也是在主线程，在线程释放连接时会延迟60s，防止子线程对socket进行读操作，
这就造成了踢下线客户端不能及时收到通知，得1min之后才能提示下线，关键这种延迟关闭个人感觉也不是太好，让主线程成取写，然后主线程取关闭套接字这样为什么就能保证操作的套接字无效，我也不太清楚
