libevent iocp/thread

#ifdef __cplusplus
extern "C"{
#endif

//包含所需要的头文件
#include "event2/event.h"
#include "event2/listener.h"
#include "event2/bufferevent.h"
#include "event2/thread.h"
#include "event2/buffer.h"

#ifdef __cplusplus
};
#endif

#ifdef _MSC_VER
#pragma comment(lib,"ws2_32.lib")
#pragma comment(lib,"libevent_core.lib")
#endif

//监听回调函数
void listener_cb(evconnlistener *listener, evutil_socket_t fd, struct sockaddr *sock, int socklen, void *arg);
//从Socket接收消息的回调函数
void socket_read_cb(bufferevent *bev, void *arg);
//从Socket事件的回调函数
void socket_event_cb(bufferevent *bev, short events, void *arg);

int main(){
WORD wVersionRequested;
WSADATA wsaData; int err;
wVersionRequested = MAKEWORD(2, 2);
err = WSAStartup(wVersionRequested, &wsaData);
if (err != 0) {
/* Tell the user that we could not find a usable */
/* Winsock DLL. */
printf("WSAStartup failed with error: %d/n", err);
return 1;
}
struct sockaddr_in sin;
memset(&sin, 0, sizeof(struct sockaddr_in));
sin.sin_family = AF_INET;
sin.sin_port = htons(2000);
//告诉libEvent使用Windows线程
//这句是必须的，不然会导致event_base_dispatch时一直处于Sleep状态，无法正常工作
evthread_use_windows_threads();
struct event_config* cfg = event_config_new();
event_config_set_flag(cfg, EVENT_BASE_FLAG_STARTUP_IOCP);
//根据CPU实际数量配置libEvent的CPU数
SYSTEM_INFO si;
GetSystemInfo(&si);
event_config_set_num_cpus_hint(cfg, si.dwNumberOfProcessors);
event_base *base;
base = event_base_new_with_config(cfg);
event_config_free(cfg);

// 监听并绑定端口
evconnlistener *listener = evconnlistener_new_bind(base, listener_cb, base, LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, 10, (struct sockaddr*)&sin, sizeof(struct sockaddr_in));
//事件分发处理
event_base_dispatch(base);
evconnlistener_free(listener);
event_base_free(base);
WSACleanup();
return 0;
}
//一个新客户端连接上服务器了
//当此函数被调用时，libevent已经帮我们accept了这个客户端。该客户端的文件描述符为fd
void listener_cb(evconnlistener *listener, evutil_socket_t fd, struct sockaddr *sock, int socklen, void *arg)
{
printf("accept a client %d/n", fd);
event_base *base = (event_base*)arg;
//为这个客户端分配一个bufferevent
bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE | BEV_OPT_THREADSAFE);
bufferevent_setcb(bev, socket_read_cb, NULL, socket_event_cb, NULL);
bufferevent_enable(bev, EV_READ | EV_PERSIST);
}

void socket_read_cb(bufferevent *bev, void *arg)
{
char msg[4096];
size_t len;
// 这里一行一行的读取
char* p = evbuffer_readln(bufferevent_get_input(bev), &len, EVBUFFER_EOL_ANY);
if (p)
{
// 如果输入exit或者quit则退出程序
// 可以使用event_base_loopexit或者event_base_loopbreak
// 它们的区别是前者会把事件处理完才退出，后者是立即退出
if (!strcmp(p, "exit"))
event_base_loopexit(bufferevent_get_base(bev), NULL);
else if (!strcmp(p, "quit"))
event_base_loopbreak(bufferevent_get_base(bev));
printf("recv data:%s/n", p);
int n = sprintf_s(msg, "srv recv data:%s/n", p);
//发送消息给客户端
bufferevent_write(bev, msg, n);
// 这里记得把分配的内存释放掉，不然会内存泄漏
free(p);
}
}

void socket_event_cb(bufferevent *bev, short events, void *arg)
{
if (events & BEV_EVENT_EOF)
printf("connection closed/n");
else if (events & BEV_EVENT_ERROR)
printf("some other error/n");
//这将自动close套接字和free读写缓冲区
bufferevent_free(bev);
}