http://blog.chukong-inc.com/index.php/2012/02/26/%E7%AE%80%E5%8D%95%E4%BB%8B%E7%BB%8Dlibevent%E5%BF%AB%E9%80%9F%E4%B8%8A%E6%89%8B/
简介
libevent是一个事件出发的网络库，使用与 windows，linux，bad, mac os 等的高性能跨平台网络库 ,支持的多种I/O 网络模型 epoll poll dev/poll select kqueue 等
Libevent安装过程
源代码文件组织结构
Libevent 库的结构
Libevent主要功能主键
Libevent普通简单例子实现
| Source code |    |
int main( )
{
int listen_fd;
struct event ev_accept;
//--相当于创建一个事件堆 以后事件可以往这里注册了--
base = event_base_new();
listen_fd = socket( AF_INET,SOCK_STREAM,0 );
if( listen_fd <0 )
return;
int reuseaddr_on = 1;
if( setsockopt( listen_fd,SOL_SOCKET,SO_REUSEADDR,&reuseaddr_on,sizeof(reuseaddr_on) ) == -1 )
{
cout<<"Error : Setsockopt failed" <<endl;
}
//--SetSocket_listenaddr--
struct sockaddr_in listen_addr;
memset( &listen_addr,0,sizeof( listen_addr ) );
listen_addr.sin_family = AF_INET;
listen_addr.sin_addr.s_addr = INADDR_ANY;
listen_addr.sin_port = htons( 80800 );
if( bind( listen_fd,(struct sockaddr*)&listen_addr,sizeof( listen_addr ) ) < 0)
{
cout<<"Error : Bind failed"<<endl;
}
if( listen( listen_fd,500 ) < 0 )
{
cout<<"Error : Listen failed"<<endl; return ;
}
if( SetNonBlock(listen_fd) < 0 )
{
cout<<"Error : SetNonBlock failed"<<endl; return;
}
//--初始化事件ev_accept 设置accept回调函数和 和事件类型--
event_set( &ev_accept,listen_fd,EV_READ|EV_PERSIST,on_accept,NULL );
//--设置完的ev_accept事件注册到 base里--
event_base_set( base,&ev_accept );
//--正事添加事件 相当于注册完的事件激活--
event_add( &ev_accept,NULL );
//--事件堆run部分--
event_base_dispatch(base);
return 1;
}
accpet callback code
| Source code | |
void on_accept(int fd,short ev,void* arg)
{
int client_fd;
struct sockaddr_in client_addr;
socklen_t client_len = sizeof( client_addr );
client_fd = accept( fd,(struct sockaddr*)&client_addr,&client_len );
if( client_fd == -1 )
{
cout<<"Error : accept client failed"<<endl;
}
if (SetNonBlock(client_fd) < 0)
{
cout<<"Error : Set client socket nonblock"<<endl;
}
static int index = 0;
cout << "客户端 "<< index <<"-----" << inet_ntoa( client_addr.sin_addr ) <<" 已链接 ~~~~~" <<endl;
index++;
//--accept到的 新客户端 注册一个recv 事件--
stMyClient* pClient = new stMyClient();
//--使用刚连接客户端的文件描述符 监视 recv 消息--
event_set( &pClient->ev_read,client_fd,EV_READ|EV_PERSIST,on_read,pClient );
event_base_set( base,&pClient->ev_read );
event_add( &pClient->ev_read,NULL );
}recv callback code
| Source code | |
void on_read( int fd,short ev,void* arg )
{
struct stMyClient* client = (stMyClient*)arg;
char buff[65535];
memset( buff,0x00,sizeof( buff ) );
int nSize = read( fd,buff,65535 );
if( nSize == 0 )
{
cout<<"Client disconnected "<<endl;
close(fd);
event_del( &client->ev_read );
delete client;
return;
}
else if( nSize < 0 )
{
cout<<"Socket failed disconnected "<<endl;
close(fd);
event_del( &client->ev_read );
delete client;
return;
}
cout<<"Read :"<<buff<<endl;
}关于使用Bufferevent 和 多线程用法
| Source code | |
//--线程回调--
void* ProcessThread( void* pthread )
{
CVitNetThread* p = (CVitNetThread*)pthread;
//--p->GetEvQueue() 这里获取到的是event_base对象--
//--这里相当于把事件堆绑定在当前线程里--
event_base_dispatch(p->GetEvQueue());
return NULL;
}
void main()
{
//----listen bind 部分同上---
//
//----------------------------
m_pEvQueue = event_base_new();
event_assign( &m_incEvent, m_pEvQueue,fd, evType, accept_cb, this);
event_base_set( m_pEvQueue,&m_incEvent );
event_add( &m_incEvent,NULL );
//--注意这里event_base堆里一个事件都没注册情况下 不能创建线程--
//--因为event_base_dispatch();此函数判断没有事件注册了的就会退出线程的--
int ret;
if ((ret = pthread_create(&m_incThreadID, NULL, ProcessThread,this)) != 0)
{
s_pLog->Log(LOG_ERROR, "%s %s => CreateThread failed",__FILE__,__FUNCTION__) ;return false;
}
}| Source code | |
void accept_cb( int fd,short ev,void* arg )
{
CVitNetThread *p = (CVitNetThread*)arg;
int client_fd = -1;
struct sockaddr_in client_addr;
socklen_t client_len = sizeof( client_addr );
client_fd = accept( fd,(struct sockaddr*)&client_addr,&client_len );
if( client_fd == -1 )
{
s_pLog->Log(LOG_ERROR, "%s %s => accept client failed fd = [%d]",__FILE__,__FUNCTION__,client_fd) ;return;
}
if (evutil_make_socket_nonblocking(client_fd) < 0)
{
s_pLog->Log(LOG_ERROR, "%s %s => Set client socket nonblock is failed",__FILE__,__FUNCTION__,client_fd) ;return;
}
//--这里创建一个缓存事件 对象 设置 recv write error 回调函数--
//--这里系统要是有recv到得信息的时候会自动调用recv_cb回调函数的
//--这里系统要是有send信息的时候自动调用write_cb回调函数
//--这里系统要是有出错或延迟的时候回调用此error_cb回调函数
bufferevent* bufferev = bufferevent_new( client_fd,recv_cb,write_cb,error_cb,p );
if( bufferev == NULL )
{
s_pLog->Log(LOG_ERROR, "%s %s => bufferev bis NULL",__FILE__,__FUNCTION__) ;return;
}
//--bufferev 事件 注册到 消息堆里 event_base 这里（ p->GetEvQueue()返回一个event_base对象）
bufferevent_base_set( p->GetEvQueue(),bufferev );
bufferevent_enable( bufferev, EV_READ | EV_WRITE );
}bufferevent recv,error
| Source code | |
void recv_cb( struct bufferevent *ev, void *arg )
{
CVitNetThread *p = (CVitNetThread*)arg;
if( p == NULL )
{
s_pLog->Log(LOG_ERROR, "%s %s => argument is NULL",__FILE__,__FUNCTION__) ;return;
}
int fd = bufferevent_getfd(ev);
char buffer[READ_MAX]; memset( buffer, 0x00,sizeof( buffer ) );
int ret = bufferevent_read(ev, &buffer,evbuffer_get_length( ev->input ));
cout<<buffer<<endl;
}
void error_cb( struct bufferevent *ev, short events ,void *arg )
{
CVitNetThread *p = (CVitNetThread*)arg;
int fd = bufferevent_getfd(ev);
if( events & BEV_EVENT_CONNECTED )
cout<<"Connect ok"<<endl;
else if( events & (BEV_EVENT_ERROR | BEV_EVENT_EOF) )
cout<<"disconnect"<<endl;
else if( events & BEV_EVENT_TIMEOUT )
cout<<"TimeOut"<<endl;
else if( events & BEV_EVENT_WRITING )
cout<<"Wrting"<<endl;
bufferevent_free(ev);
}