static void ui_writer(evutil_socket_t fd, short what, void *arg) { struct uiclient *client = arg; int n = evbuffer_write_atmost(client->outbuf, fd, -1); if (n == -1) { if (errno == EINTR || errno == EAGAIN) goto schedule; ui_dead(client); return; } else if (n == 0) { ui_dead(client); return; } schedule: if (evbuffer_get_length(client->outbuf)) event_add(client->ev_write, NULL); }
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); }
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); }