bufferevent實現的echoserver

// echoserver.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <event2/listener.h>
#include <event2/bufferevent.h>
#include <event2/buffer.h>

#include <WinSock2.h>

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

static void echo_read_cb(struct bufferevent *bev, void *ctx)
{
    /* This callback is invoked when there is data to read on bev. */
    struct evbuffer *input = bufferevent_get_input(bev);
    struct evbuffer *output = bufferevent_get_output(bev);

    /* Copy all the data from the input buffer to the output buffer. */
    evbuffer_add_buffer(output, input);
}

static void echo_event_cb(struct bufferevent *bev, short events, void *ctx)
{
    if (events & BEV_EVENT_ERROR)
		perror("Error from bufferevent");
    if (events & (BEV_EVENT_EOF | BEV_EVENT_ERROR)) {
        bufferevent_free(bev);
    }
}

static void accept_conn_cb(struct evconnlistener *listener,
    evutil_socket_t fd, struct sockaddr *address, int socklen,
    void *ctx)
{
    /* We got a new connection! Set up a bufferevent for it. */
    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, NULL, echo_event_cb, NULL);

    bufferevent_enable(bev, EV_READ|EV_WRITE);
}

static void accept_error_cb(struct evconnlistener *listener, void *ctx)
{
    struct event_base *base = evconnlistener_get_base(listener);
    int err = EVUTIL_SOCKET_ERROR();
    fprintf(stderr, "Got an error %d (%s) on the listener. "
            "Shutting down.\n", err, evutil_socket_error_to_string(err));

    event_base_loopexit(base, NULL);
}

int main(int argc, char **argv)
{
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;

	wVersionRequested = MAKEWORD( 2, 2 );
	err = WSAStartup( wVersionRequested, &wsaData );
	if ( err != 0 ) {
		return -1;
	}

    struct event_base *base;
    struct evconnlistener *listener;
    struct sockaddr_in sin;

    int port = 9876;

    if (argc > 1) {
            port = atoi(argv[1]);
    }
    if (port<=0 || port>65535) {
            puts("Invalid port");
            return 1;
    }

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

    /* Clear the sockaddr before using it, in case there are extra
     * platform-specific fields that can mess us up. */
    memset(&sin, 0, sizeof(sin));
    /* This is an INET address */
    sin.sin_family = AF_INET;
    /* Listen on 0.0.0.0 */
    sin.sin_addr.s_addr = htonl(0);
    /* Listen on the given port. */
    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("Couldn't create listener");
            return 1;
    }
    evconnlistener_set_error_cb(listener, accept_error_cb);

    event_base_dispatch(base);
	WSACleanup();
    return 0;
}