libevent简单应用4

#include <event2/listener.h>

#include <event2/bufferevent.h>
#include <event2/buffer.h>

#include <arpa/inet.h>

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

/* 设置计数，只允许echo_write_cb调用一次 */
static int count = 1;

/*当有数据可读的时候，会调用这个函数 */
static void echo_read_cb(struct bufferevent *bev, void *ctx)
{
	printf("Echo_read_cb is called
");
	struct evbuffer *input = bufferevent_get_input(bev);
	struct evbuffer *output = bufferevent_get_output(bev);
	
	size_t len = evbuffer_get_length(input);
	printf("evbuffer input length is: %lu
", (unsigned long)len);

	//evbuffer_add_buffer(output, input);

	char buf[1024];
	int n;
	n = evbuffer_remove(input, buf, sizeof(buf));
	printf("copy bytes == %d
", n);
	printf("copy buf: %s
", buf);
}

static void echo_write_cb(struct bufferevent *bev, void *ctx)
{
	printf("echo_write_cb is called
");
	char sendbuffer[] = "yes, i recv your message!
";	

	struct evbuffer *output = bufferevent_get_output(bev);	
	
	if(count == 1)
	{
		int result = evbuffer_add(output, sendbuffer, strlen(sendbuffer));
		printf("evbuffer_add result = %d
", result);	
	}
	
	count++;
	int len = evbuffer_get_length(output);
	evbuffer_drain(output, len);	
}


/*当客户端结束的时候，肯定会调用这个函数  */
static void echo_event_cb(struct bufferevent *bev, short events, void *ctx)
{
	printf("echo_event_cb is called
");
	if(events & BEV_EVENT_ERROR)
		perror("Error from bufferevent");
	if(events & BEV_EVENT_EOF | BEV_EVENT_ERROR)
	{
		bufferevent_free(bev);
		printf("bufferevent_free is called
");
	}
}	


static void accept_conn_cb(struct evconnlistener *listener, evutil_socket_t fd, 
	struct sockaddr*address, int socklen, void *ctx)
{
	printf("Accept_conn_cb is called
");
	struct event_base *base = evconnlistener_get_base(listener);
	struct bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
	
	bufferevent_setcb(bev, echo_read_cb, echo_write_cb, echo_event_cb, NULL);
	
	bufferevent_enable(bev, EV_READ|EV_WRITE);	
}

static void accept_error_cb(struct evconnlistener *listener, void *ctx)
{	
	printf("Accept_error_cb is called
");
	struct event_base *base = evconnlistener_get_base(listener);
	int err = EVUTIL_SOCKET_ERROR();
	fprintf(stderr, "Got an error");
	
	event_base_loopexit(base, NULL);
	
}

int main(int argc, char **argv)
{
	struct event_base *base;
	struct evconnlistener *listener;
	struct sockaddr_in sin;
	
	int port = 9527;
	
	if(argc > 1)
	{
		port = atoi(argv[1]);
	}
	if(port <= 0 || port > 65535)
	{
		puts("Invalid port");
		return 1;
	}

	base = event_base_new();
	if(!base)
	{
		puts("could't open event_base");
		return 1;
	}

	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = htonl(0);
	sin.sin_port = htons(port);
	
	listener = evconnlistener_new_bind(base, accept_conn_cb, NULL,
		LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE, -1,
		(struct sockaddr*)&sin, sizeof(sin));
	if(!listener)
	{
		perror("could't not create listener");
		return 1;
	}
	
	evconnlistener_set_error_cb(listener, accept_error_cb);
	
	event_base_dispatch(base);
	return 0;
}

说明：

利用evconnlistener_new_bind实现一个tcp服务器端，evconnlistener_new_bind源码本身调用了evconnlistener_new函数，源码已经封装了Bind和Listen函数。