[C++] live555 epoll 实现

　　live555的任务调度是基于select的，其实select也不是很差，主要看使用场合，在并发量不是很大的时候效果还是很好的，而且很多平台都支持。当然，在Linux下有更好的选择，那就是epoll，将live555的任务调度改为epoll，能够进一步提高网络事件的处理能力，我在 BasicTaskScheduler 下添加了对epoll的支持，并没有删除select的实现，这样可以同时在windows和linux下编译使用。下面贴出主要部分，后面会给出代码的下载地址。
SingleStep 修改：

 1 void BasicTaskScheduler::SingleStep(unsigned maxDelayTime) 
 2 {
 3     // ....


 4     unsigned timeout = tv_timeToDelay.tv_sec*1000+(tv_timeToDelay.tv_usec/1000);
 5     struct epoll_event events[1] = {0};
 6 
 7     int numEvent = epoll_wait(_epollfd, events, 1, timeout);
 8     if(numEvent < 0)
 9     {
10         if (errno != EINTR)
11             internalError();        
12     }
13     else
14     {
15         HandlerDescriptor* handler = NULL;
16         int conditionSet = 0;
17         for(int i=0; i<numEvent; i++)
18         {
19             if(events[i].data.ptr == NULL)
20                 continue;
21             handler = (HandlerDescriptor*)(events[i].data.ptr);
22             conditionSet = 0;
23             if(events[i].events & EPOLLIN)
24                 conditionSet |= SOCKET_READABLE;
25             if(events[i].events & EPOLLOUT)
26                 conditionSet |= SOCKET_WRITABLE;
27             if(events[i].events&EPOLLERR || events[i].events&EPOLLPRI)
28                 conditionSet |= SOCKET_EXCEPTION;
29             
30             if ((conditionSet&handler->conditionSet) != 0 
31                 && handler->handlerProc != NULL ) 
32             {
33                 fLastHandledSocketNum = handler->socketNum;
34                 (*handler->handlerProc)(handler->clientData, conditionSet);
35             }
36         }        
37     }
38 
39     // ....           
40 }

setBackgroundHandling 修改：

void BasicTaskScheduler
  ::setBackgroundHandling(int socketNum, int conditionSet, BackgroundHandlerProc* handlerProc, void* clientData) 
{
    // ...
        
    HandlerIterator iter(*fHandlers);   
        HandlerDescriptor* handler = NULL;
        while ((handler = iter.next()) != NULL) // lookupHandler
        {
          if (handler->socketNum == socketNum) 
            break;
        }
        struct epoll_event event = {0};
        event.data.ptr = handler;
        if (conditionSet&SOCKET_READABLE) 
            event.events |= EPOLLIN;
        if (conditionSet&SOCKET_WRITABLE) 
            event.events |= EPOLLOUT;
        if (conditionSet&SOCKET_EXCEPTION) 
            event.events |= (EPOLLPRI|EPOLLERR);
        if(epoll_ctl(_epollfd, EPOLL_CTL_ADD, socketNum, &event) < 0)
        {
            if(errno == EEXIST)
                epoll_ctl(_epollfd, EPOLL_CTL_MOD, socketNum, &event);
        }             
      
    // ...
}

moveSocketHandling 修改：

void BasicTaskScheduler::moveSocketHandling(int oldSocketNum, int newSocketNum)
{
    // ...
    
    HandlerIterator iter(*fHandlers);        
    HandlerDescriptor* handler = NULL;
    while ((handler = iter.next()) != NULL) // lookupHandler
    {
      if (handler->socketNum == oldSocketNum) 
        break;
    }

    if(!handler)
        return ;

    struct epoll_event event = {0};
    event.data.ptr = handler;    
    if(handler->conditionSet&SOCKET_READABLE)  
        event.events |= EPOLLIN;
    if(handler->conditionSet&SOCKET_WRITABLE)  
        event.events |= EPOLLOUT;
    if(handler->conditionSet&SOCKET_EXCEPTION) 
        event.events |= (EPOLLPRI|EPOLLERR);
    if(event.events != 0)
    {
        epoll_ctl(_epollfd, EPOLL_CTL_DEL, oldSocketNum, NULL);
        epoll_ctl(_epollfd, EPOLL_CTL_ADD, newSocketNum, &event);
    }

#if defined(__linux) || defined(__linux__) 
    struct epoll_event event = {0};
    event.data.ptr = handler;    
    if(handler->conditionSet&SOCKET_READABLE)  
        event.events |= EPOLLIN;
    if(handler->conditionSet&SOCKET_WRITABLE)  
        event.events |= EPOLLOUT;
    if(handler->conditionSet&SOCKET_EXCEPTION) 
        event.events |= (EPOLLPRI|EPOLLERR);
    if(event.events != 0)
    {
        epoll_ctl(_epollfd, EPOLL_CTL_DEL, oldSocketNum, NULL);
        epoll_ctl(_epollfd, EPOLL_CTL_ADD, newSocketNum, &event);
    }
#else
     // ...
#endif
    // ...
}

epoll的主要实现就是这些，我在windows和linux下编译通过，做了简单的测试，如果有什么疑问可以提出。后续我会给出live555多线程的实现。
我把代码放在了github，希望对你有帮助 ^_^
代码： https://github.com/PHZ76/live555_epoll

[C++]live555 epoll 实现