Example #1
0
struct bufferevent *
bufferevent_socket_new(struct event_base *base, evutil_socket_t fd,
    int options)
{
	struct bufferevent_private *bufev_p;
	struct bufferevent *bufev;

#ifdef _WIN32
	if (base && event_base_get_iocp_(base))
		return bufferevent_async_new_(base, fd, options);
#endif

	if ((bufev_p = mm_calloc(1, sizeof(struct bufferevent_private)))== NULL)
		return NULL;

	if (bufferevent_init_common_(bufev_p, base, &bufferevent_ops_socket,
				    options) < 0) {
		mm_free(bufev_p);
		return NULL;
	}
	bufev = &bufev_p->bev;
	evbuffer_set_flags(bufev->output, EVBUFFER_FLAG_DRAINS_TO_FD);

	event_assign(&bufev->ev_read, bufev->ev_base, fd,
	    EV_READ|EV_PERSIST, bufferevent_readcb, bufev);
	event_assign(&bufev->ev_write, bufev->ev_base, fd,
	    EV_WRITE|EV_PERSIST, bufferevent_writecb, bufev);

	evbuffer_add_cb(bufev->output, bufferevent_socket_outbuf_cb, bufev);

	evbuffer_freeze(bufev->input, 0);
	evbuffer_freeze(bufev->output, 1);

	return bufev;
}
Example #2
0
struct bufferevent *
bufferevent_socket_new(struct event_base *base, evutil_socket_t fd,
    int options)
{
	struct bufferevent_private *bufev_p;
	struct bufferevent *bufev;

#ifdef WIN32
	if (base && event_base_get_iocp(base))
		return bufferevent_async_new(base, fd, options);
#endif

	if ((bufev_p = mm_calloc(1, sizeof(struct bufferevent_private)))== NULL)
		return NULL;

	if (bufferevent_init_common(bufev_p, base, &bufferevent_ops_socket,
				    options) < 0) {
		mm_free(bufev_p);
		return NULL;
	}
	bufev = &bufev_p->bev;
	//设置将evbuffer的数据向fd传 
	evbuffer_set_flags(bufev->output, EVBUFFER_FLAG_DRAINS_TO_FD);

    //设置读写回调
	event_assign(&bufev->ev_read, bufev->ev_base, fd,
	    EV_READ|EV_PERSIST, bufferevent_readcb, bufev);
	event_assign(&bufev->ev_write, bufev->ev_base, fd,
	    EV_WRITE|EV_PERSIST, bufferevent_writecb, bufev);

    //设置evbuffer的回调函数,使得外界给写缓冲区添加数据时,能触发  
    //写操作,这个回调对于写事件的监听是很重要的  
	evbuffer_add_cb(bufev->output, bufferevent_socket_outbuf_cb, bufev);

	/* 虽然这里冻结了,但实际上Libevent在读数据或者写数据之前会解冻的读完或者写完数据后,又会马上冻结。
	 * 这主要防止数据被意外修改。用户一般不会直接调用evbuffer_freeze或者evbuffer_unfreeze函数。
	 * 一切的冻结和解冻操作都由Libevent内部完成。还有一点要注意,因为这里只是把写缓冲区的头部冻结了。
	 * 所以还是可以往写缓冲区的尾部追加数据。同样,此时也是可以从读缓冲区读取数据。这个是必须的。
	 * 因为在Libevent内部不解冻的时候,用户需要从读缓冲区中获取数据(这相当于从socket fd中读取数据),
	 * 用户也需要把数据写到写缓冲区中(这相当于把数据写入到socket fd中)。*/

    //冻结读缓冲区的尾部,未解冻之前不能往读缓冲区追加数据  
    //也就是说不能从socket fd中读取数据  
	evbuffer_freeze(bufev->input, 0);

	//冻结写缓冲区的头部,未解冻之前不能把写缓冲区的头部数据删除  
    //也就是说不能把数据写到socket fd  
	evbuffer_freeze(bufev->output, 1);

	return bufev;
}
Example #3
0
static void
bufferevent_writecb(evutil_socket_t fd, short event, void *arg)
{
	struct bufferevent *bufev = arg;
	struct bufferevent_private *bufev_p =
	    EVUTIL_UPCAST(bufev, struct bufferevent_private, bev);
	int res = 0;
	short what = BEV_EVENT_WRITING;
	int connected = 0;
	ev_ssize_t atmost = -1;

	bufferevent_incref_and_lock_(bufev);

	if (event == EV_TIMEOUT) {
		/* Note that we only check for event==EV_TIMEOUT. If
		 * event==EV_TIMEOUT|EV_WRITE, we can safely ignore the
		 * timeout, since a read has occurred */
		what |= BEV_EVENT_TIMEOUT;
		goto error;
	}
	if (bufev_p->connecting) {
		int c = evutil_socket_finished_connecting_(fd);
		/* we need to fake the error if the connection was refused
		 * immediately - usually connection to localhost on BSD */
		if (bufev_p->connection_refused) {
		  bufev_p->connection_refused = 0;
		  c = -1;
		}

		if (c == 0)
			goto done;

		bufev_p->connecting = 0;
		if (c < 0) {
			event_del(&bufev->ev_write);
			event_del(&bufev->ev_read);
			bufferevent_run_eventcb_(bufev, BEV_EVENT_ERROR);
			goto done;
		} else {
			connected = 1;
#ifdef _WIN32
			if (BEV_IS_ASYNC(bufev)) {
				event_del(&bufev->ev_write);
				bufferevent_async_set_connected_(bufev);
				bufferevent_run_eventcb_(bufev,
						BEV_EVENT_CONNECTED);
				goto done;
			}
#endif
			bufferevent_run_eventcb_(bufev,
					BEV_EVENT_CONNECTED);
			if (!(bufev->enabled & EV_WRITE) ||
			    bufev_p->write_suspended) {
				event_del(&bufev->ev_write);
				goto done;
			}
		}
	}

	atmost = bufferevent_get_write_max_(bufev_p);

	if (bufev_p->write_suspended)
		goto done;

	if (evbuffer_get_length(bufev->output)) {
		evbuffer_unfreeze(bufev->output, 1);
		res = evbuffer_write_atmost(bufev->output, fd, atmost);
		evbuffer_freeze(bufev->output, 1);
		if (res == -1) {
			int err = evutil_socket_geterror(fd);
			if (EVUTIL_ERR_RW_RETRIABLE(err))
				goto reschedule;
			what |= BEV_EVENT_ERROR;
		} else if (res == 0) {
			/* eof case
			   XXXX Actually, a 0 on write doesn't indicate
			   an EOF. An ECONNRESET might be more typical.
			 */
			what |= BEV_EVENT_EOF;
		}
		if (res <= 0)
			goto error;

		bufferevent_decrement_write_buckets_(bufev_p, res);
	}

	if (evbuffer_get_length(bufev->output) == 0) {
		event_del(&bufev->ev_write);
	}

	/*
	 * Invoke the user callback if our buffer is drained or below the
	 * low watermark.
	 */
	if ((res || !connected) &&
	    evbuffer_get_length(bufev->output) <= bufev->wm_write.low) {
		bufferevent_run_writecb_(bufev);
	}

	goto done;

 reschedule:
	if (evbuffer_get_length(bufev->output) == 0) {
		event_del(&bufev->ev_write);
	}
	goto done;

 error:
	bufferevent_disable(bufev, EV_WRITE);
	bufferevent_run_eventcb_(bufev, what);

 done:
	bufferevent_decref_and_unlock_(bufev);
}
Example #4
0
static void
bufferevent_readcb(evutil_socket_t fd, short event, void *arg)
{
	struct bufferevent *bufev = arg;
	struct bufferevent_private *bufev_p =
	    EVUTIL_UPCAST(bufev, struct bufferevent_private, bev);
	struct evbuffer *input;
	int res = 0;
	short what = BEV_EVENT_READING;
	ev_ssize_t howmuch = -1, readmax=-1;

	bufferevent_incref_and_lock_(bufev);

	if (event == EV_TIMEOUT) {
		/* Note that we only check for event==EV_TIMEOUT. If
		 * event==EV_TIMEOUT|EV_READ, we can safely ignore the
		 * timeout, since a read has occurred */
		what |= BEV_EVENT_TIMEOUT;
		goto error;
	}

	input = bufev->input;

	/*
	 * If we have a high watermark configured then we don't want to
	 * read more data than would make us reach the watermark.
	 */
	if (bufev->wm_read.high != 0) {
		howmuch = bufev->wm_read.high - evbuffer_get_length(input);
		/* we somehow lowered the watermark, stop reading */
		if (howmuch <= 0) {
			bufferevent_wm_suspend_read(bufev);
			goto done;
		}
	}
	readmax = bufferevent_get_read_max_(bufev_p);
	if (howmuch < 0 || howmuch > readmax) /* The use of -1 for "unlimited"
					       * uglifies this code. XXXX */
		howmuch = readmax;
	if (bufev_p->read_suspended)
		goto done;

	evbuffer_unfreeze(input, 0);
	res = evbuffer_read(input, fd, (int)howmuch); /* XXXX evbuffer_read would do better to take and return ev_ssize_t */
	evbuffer_freeze(input, 0);

	if (res == -1) {
		int err = evutil_socket_geterror(fd);
		if (EVUTIL_ERR_RW_RETRIABLE(err))
			goto reschedule;
		/* error case */
		what |= BEV_EVENT_ERROR;
	} else if (res == 0) {
		/* eof case */
		what |= BEV_EVENT_EOF;
	}

	if (res <= 0)
		goto error;

	bufferevent_decrement_read_buckets_(bufev_p, res);

	/* Invoke the user callback - must always be called last */
	if (evbuffer_get_length(input) >= bufev->wm_read.low)
		bufferevent_run_readcb_(bufev);

	goto done;

 reschedule:
	goto done;

 error:
	bufferevent_disable(bufev, EV_READ);
	bufferevent_run_eventcb_(bufev, what);

 done:
	bufferevent_decref_and_unlock_(bufev);
}
Example #5
0
int
evbuffer_launch_read(struct evbuffer *buf, size_t at_most,
		struct event_overlapped *ol)
{
	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
	int r = -1, i;
	int nvecs;
	int npin=0;
	struct evbuffer_chain *chain=NULL, **chainp;
	DWORD bytesRead;
	DWORD flags = 0;
	struct evbuffer_iovec vecs[MAX_WSABUFS];

	if (!buf_o)
		return -1;
	EVBUFFER_LOCK(buf);
	EVUTIL_ASSERT(!buf_o->write_in_progress);
	if (buf->freeze_end || buf_o->read_in_progress)
		goto done;

	buf_o->first_pinned = NULL;
	buf_o->n_buffers = 0;
	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));

	if (_evbuffer_expand_fast(buf, at_most, MAX_WSABUFS) == -1)
		goto done;
	evbuffer_freeze(buf, 0);

	nvecs = _evbuffer_read_setup_vecs(buf, at_most,
	    vecs, MAX_WSABUFS, &chainp, 1);
	for (i=0;i<nvecs;++i) {
		WSABUF_FROM_EVBUFFER_IOV(
			&buf_o->buffers[i],
			&vecs[i]);
	}

	buf_o->n_buffers = nvecs;
	buf_o->first_pinned = chain = *chainp;

	npin=0;
	for ( ; chain; chain = chain->next) {
		_evbuffer_chain_pin(chain, EVBUFFER_MEM_PINNED_R);
		++npin;
	}
	EVUTIL_ASSERT(npin == nvecs);

	_evbuffer_incref(buf);
	if (WSARecv(buf_o->fd, buf_o->buffers, nvecs, &bytesRead, &flags,
		    &ol->overlapped, NULL)) {
		int error = WSAGetLastError();
		if (error != WSA_IO_PENDING) {
			/* An actual error. */
			pin_release(buf_o, EVBUFFER_MEM_PINNED_R);
			evbuffer_unfreeze(buf, 0);
			evbuffer_free(buf); /* decref */
			goto done;
		}
	}

	buf_o->read_in_progress = 1;
	r = 0;
done:
	EVBUFFER_UNLOCK(buf);
	return r;
}
Example #6
0
int
evbuffer_launch_write(struct evbuffer *buf, ev_ssize_t at_most,
		struct event_overlapped *ol)
{
	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
	int r = -1;
	int i;
	struct evbuffer_chain *chain;
	DWORD bytesSent;

	if (!buf) {
		/* No buffer, or it isn't overlapped */
		return -1;
	}

	EVBUFFER_LOCK(buf);
	EVUTIL_ASSERT(!buf_o->read_in_progress);
	if (buf->freeze_start || buf_o->write_in_progress)
		goto done;
	if (!buf->total_len) {
		/* Nothing to write */
		r = 0;
		goto done;
	} else if (at_most < 0 || (size_t)at_most > buf->total_len) {
		at_most = buf->total_len;
	}
	evbuffer_freeze(buf, 1);

	buf_o->first_pinned = NULL;
	buf_o->n_buffers = 0;
	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));

	chain = buf_o->first_pinned = buf->first;

	for (i=0; i < MAX_WSABUFS && chain; ++i, chain=chain->next) {
		WSABUF *b = &buf_o->buffers[i];
		b->buf = (char*)( chain->buffer + chain->misalign );
		_evbuffer_chain_pin(chain, EVBUFFER_MEM_PINNED_W);

		if ((size_t)at_most > chain->off) {
			/* XXXX Cast is safe for now, since win32 has no
			   mmaped chains.  But later, we need to have this
			   add more WSAbufs if chain->off is greater than
			   ULONG_MAX */
			b->len = (unsigned long)chain->off;
			at_most -= chain->off;
		} else {
			b->len = (unsigned long)at_most;
			++i;
			break;
		}
	}

	buf_o->n_buffers = i;
	_evbuffer_incref(buf);
	if (WSASend(buf_o->fd, buf_o->buffers, i, &bytesSent, 0,
		&ol->overlapped, NULL)) {
		int error = WSAGetLastError();
		if (error != WSA_IO_PENDING) {
			/* An actual error. */
			pin_release(buf_o, EVBUFFER_MEM_PINNED_W);
			evbuffer_unfreeze(buf, 1);
			evbuffer_free(buf); /* decref */
			goto done;
		}
	}

	buf_o->write_in_progress = 1;
	r = 0;
done:
	EVBUFFER_UNLOCK(buf);
	return r;
}
Example #7
0
static void
bufferevent_writecb(evutil_socket_t fd, short event, void *arg)
{
	struct bufferevent *bufev = arg;
	struct bufferevent_private *bufev_p =
	    EVUTIL_UPCAST(bufev, struct bufferevent_private, bev);
	int res = 0;
	short what = BEV_EVENT_WRITING;
	int connected = 0;
	ev_ssize_t atmost = -1;

	_bufferevent_incref_and_lock(bufev);

	if (event == EV_TIMEOUT) {
		/* Note that we only check for event==EV_TIMEOUT. If
		 * event==EV_TIMEOUT|EV_WRITE, we can safely ignore the
		 * timeout, since a read has occurred */
		what |= BEV_EVENT_TIMEOUT;
		goto error;
	}
	//正在连接服务器...
	if (bufev_p->connecting) {
		int c = evutil_socket_finished_connecting(fd);
		/* we need to fake the error if the connection was refused
		 * immediately - usually connection to localhost on BSD */
		if (bufev_p->connection_refused) {  //在bufferevent_socket_connect中被设置
		  bufev_p->connection_refused = 0;
		  c = -1;
		}

		if (c == 0) //正在连接,继续监听可写。
			goto done;

		bufev_p->connecting = 0;
		if (c < 0) {  //连接发生错误
			event_del(&bufev->ev_write);
			event_del(&bufev->ev_read);
			_bufferevent_run_eventcb(bufev, BEV_EVENT_ERROR);
			goto done;
		} else {  //连接成功
			connected = 1;
#ifdef WIN32
			if (BEV_IS_ASYNC(bufev)) {
				event_del(&bufev->ev_write);
				bufferevent_async_set_connected(bufev);
				_bufferevent_run_eventcb(bufev,
						BEV_EVENT_CONNECTED);
				goto done;
			}
#endif
            //连接成功,调用用户错误处理函数。比较奇怪。
			_bufferevent_run_eventcb(bufev,
					BEV_EVENT_CONNECTED);
			if (!(bufev->enabled & EV_WRITE) ||
			    bufev_p->write_suspended) {
				event_del(&bufev->ev_write);
				goto done;
			}
		}
	}

	atmost = _bufferevent_get_write_max(bufev_p);

    //写被挂起
	if (bufev_p->write_suspended)
		goto done;

    //存在可写数据
	if (evbuffer_get_length(bufev->output)) {
		evbuffer_unfreeze(bufev->output, 1);
		//将缓冲区数据写入socket。
		res = evbuffer_write_atmost(bufev->output, fd, atmost);
		evbuffer_freeze(bufev->output, 1);
		if (res == -1) {  //写发生错误
			int err = evutil_socket_geterror(fd);
			if (EVUTIL_ERR_RW_RETRIABLE(err))  //socket缓冲区满,一次未写完,继续监听可写事件,等待下次写入。
				goto reschedule;
			what |= BEV_EVENT_ERROR;  //写发生异常错误
		} else if (res == 0) {
			/* eof case
			   XXXX Actually, a 0 on write doesn't indicate
			   an EOF. An ECONNRESET might be more typical.
			 */
			what |= BEV_EVENT_EOF;
		}
		if (res <= 0)
			goto error;

		_bufferevent_decrement_write_buckets(bufev_p, res);
	}

    //缓冲区数据已写完,删除写事件。
	if (evbuffer_get_length(bufev->output) == 0) {
		event_del(&bufev->ev_write);
	}

	/* 低于写低水位,调用用户回调。
	 */
	if ((res || !connected) &&
	    evbuffer_get_length(bufev->output) <= bufev->wm_write.low) {
		_bufferevent_run_writecb(bufev);
	}

	goto done;

 reschedule:
	if (evbuffer_get_length(bufev->output) == 0) {
		event_del(&bufev->ev_write);
	}
	goto done;

 error:
	bufferevent_disable(bufev, EV_WRITE);
	_bufferevent_run_eventcb(bufev, what);

 done:
	_bufferevent_decref_and_unlock(bufev);
}
Example #8
0
static void
bufferevent_readcb(evutil_socket_t fd, short event, void *arg)
{
	struct bufferevent *bufev = arg;
	struct bufferevent_private *bufev_p =
	    EVUTIL_UPCAST(bufev, struct bufferevent_private, bev);
	struct evbuffer *input;
	int res = 0;
	short what = BEV_EVENT_READING;
	ev_ssize_t howmuch = -1, readmax=-1;

	_bufferevent_incref_and_lock(bufev);

	if (event == EV_TIMEOUT) {
		/* Note that we only check for event==EV_TIMEOUT. If
		 * event==EV_TIMEOUT|EV_READ, we can safely ignore the
		 * timeout, since a read has occurred */
		what |= BEV_EVENT_TIMEOUT;
		goto error;
	}

	input = bufev->input;

	/*
	 * If we have a high watermark configured then we don't want to
	 * read more data than would make us reach the watermark.
	 */
	if (bufev->wm_read.high != 0) {
		howmuch = bufev->wm_read.high - evbuffer_get_length(input);
		/* 缓冲区超过高水位,挂起读。 */
		if (howmuch <= 0) {
			bufferevent_wm_suspend_read(bufev);
			goto done;
		}
	}
	
	//因为用户可以限速,所以这么要检测最大的可读大小。  
    //如果没有限速的话,那么将返回16384字节,即16K  
    //默认情况下是没有限速的。  
	readmax = _bufferevent_get_read_max(bufev_p);
	if (howmuch < 0 || howmuch > readmax) /* The use of -1 for "unlimited"
					       * uglifies this code. XXXX */
		howmuch = readmax;
	if (bufev_p->read_suspended)
		goto done;

	evbuffer_unfreeze(input, 0);
	res = evbuffer_read(input, fd, (int)howmuch); /* XXXX evbuffer_read would do better to take and return ev_ssize_t */
	evbuffer_freeze(input, 0);

	if (res == -1) {
		int err = evutil_socket_geterror(fd);
		if (EVUTIL_ERR_RW_RETRIABLE(err))  //EINTER or EAGAIN 
			goto reschedule;
		/* error case */
		what |= BEV_EVENT_ERROR;
	} else if (res == 0) {
		/* eof case */
		what |= BEV_EVENT_EOF;
	}

	if (res <= 0)
		goto error;

	_bufferevent_decrement_read_buckets(bufev_p, res);

	/* 数据大于低水平,调用用户设置的回调。 */
	if (evbuffer_get_length(input) >= bufev->wm_read.low)
		_bufferevent_run_readcb(bufev);

	goto done;

 reschedule:
	goto done;

 error:
	bufferevent_disable(bufev, EV_READ);
	_bufferevent_run_eventcb(bufev, what);

 done:
	_bufferevent_decref_and_unlock(bufev);
}