static int js_os_poll()

in src/couch_quickjs/quickjs/quickjs-libc.c [2401:2511]

• 99 lines of code
• 21 McCabe index (conditional complexity)

static int js_os_poll(JSContext *ctx)
{
    JSRuntime *rt = JS_GetRuntime(ctx);
    JSThreadState *ts = JS_GetRuntimeOpaque(rt);
    int ret, fd_max, min_delay;
    int64_t cur_time, delay;
    fd_set rfds, wfds;
    JSOSRWHandler *rh;
    struct list_head *el;
    struct timeval tv, *tvp;

    /* only check signals in the main thread */
    if (!ts->recv_pipe &&
        unlikely(os_pending_signals != 0)) {
        JSOSSignalHandler *sh;
        uint64_t mask;

        list_for_each(el, &ts->os_signal_handlers) {
            sh = list_entry(el, JSOSSignalHandler, link);
            mask = (uint64_t)1 << sh->sig_num;
            if (os_pending_signals & mask) {
                os_pending_signals &= ~mask;
                call_handler(ctx, sh->func);
                return 0;
            }
        }
    }

    if (list_empty(&ts->os_rw_handlers) && list_empty(&ts->os_timers) &&
        list_empty(&ts->port_list))
        return -1; /* no more events */

    if (!list_empty(&ts->os_timers)) {
        cur_time = get_time_ms();
        min_delay = 10000;
        list_for_each(el, &ts->os_timers) {
            JSOSTimer *th = list_entry(el, JSOSTimer, link);
            delay = th->timeout - cur_time;
            if (delay <= 0) {
                JSValue func;
                /* the timer expired */
                func = th->func;
                th->func = JS_UNDEFINED;
                free_timer(rt, th);
                call_handler(ctx, func);
                JS_FreeValue(ctx, func);
                return 0;
            } else if (delay < min_delay) {
                min_delay = delay;
            }
        }
        tv.tv_sec = min_delay / 1000;
        tv.tv_usec = (min_delay % 1000) * 1000;
        tvp = &tv;
    } else {
        tvp = NULL;
    }

    FD_ZERO(&rfds);
    FD_ZERO(&wfds);
    fd_max = -1;
    list_for_each(el, &ts->os_rw_handlers) {
        rh = list_entry(el, JSOSRWHandler, link);
        fd_max = max_int(fd_max, rh->fd);
        if (!JS_IsNull(rh->rw_func[0]))
            FD_SET(rh->fd, &rfds);
        if (!JS_IsNull(rh->rw_func[1]))
            FD_SET(rh->fd, &wfds);
    }

    list_for_each(el, &ts->port_list) {
        JSWorkerMessageHandler *port = list_entry(el, JSWorkerMessageHandler, link);
        if (!JS_IsNull(port->on_message_func)) {
            JSWorkerMessagePipe *ps = port->recv_pipe;
            fd_max = max_int(fd_max, ps->waker.read_fd);
            FD_SET(ps->waker.read_fd, &rfds);
        }
    }

    ret = select(fd_max + 1, &rfds, &wfds, NULL, tvp);
    if (ret > 0) {
        list_for_each(el, &ts->os_rw_handlers) {
            rh = list_entry(el, JSOSRWHandler, link);
            if (!JS_IsNull(rh->rw_func[0]) &&
                FD_ISSET(rh->fd, &rfds)) {
                call_handler(ctx, rh->rw_func[0]);
                /* must stop because the list may have been modified */
                goto done;
            }
            if (!JS_IsNull(rh->rw_func[1]) &&
                FD_ISSET(rh->fd, &wfds)) {
                call_handler(ctx, rh->rw_func[1]);
                /* must stop because the list may have been modified */
                goto done;
            }
        }

        list_for_each(el, &ts->port_list) {
            JSWorkerMessageHandler *port = list_entry(el, JSWorkerMessageHandler, link);
            if (!JS_IsNull(port->on_message_func)) {
                JSWorkerMessagePipe *ps = port->recv_pipe;
                if (FD_ISSET(ps->waker.read_fd, &rfds)) {
                    if (handle_posted_message(rt, ctx, port))
                        goto done;
                }
            }
        }
    }
 done:
    return 0;
}