static int js_os_poll()

in src/couch_quickjs/quickjs/quickjs-libc.c [2306:2397]

• 81 lines of code
• 20 McCabe index (conditional complexity)

static int js_os_poll(JSContext *ctx)
{
    JSRuntime *rt = JS_GetRuntime(ctx);
    JSThreadState *ts = JS_GetRuntimeOpaque(rt);
    int min_delay, count;
    int64_t cur_time, delay;
    JSOSRWHandler *rh;
    struct list_head *el;
    HANDLE handles[MAXIMUM_WAIT_OBJECTS]; // 64

    /* XXX: handle signals if useful */

    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;
            }
        }
    } else {
        min_delay = -1;
    }

    count = 0;
    list_for_each(el, &ts->os_rw_handlers) {
        rh = list_entry(el, JSOSRWHandler, link);
        if (rh->fd == 0 && !JS_IsNull(rh->rw_func[0])) {
            handles[count++] = (HANDLE)_get_osfhandle(rh->fd); // stdin
            if (count == (int)countof(handles))
                break;
        }
    }

    list_for_each(el, &ts->port_list) {
        JSWorkerMessageHandler *port = list_entry(el, JSWorkerMessageHandler, link);
        if (JS_IsNull(port->on_message_func))
            continue;
        handles[count++] = port->recv_pipe->waker.handle;
        if (count == (int)countof(handles))
            break;
    }

    if (count > 0) {
        DWORD ret, timeout = INFINITE;
        if (min_delay != -1)
            timeout = min_delay;
        ret = WaitForMultipleObjects(count, handles, FALSE, timeout);

        if (ret < count) {
            list_for_each(el, &ts->os_rw_handlers) {
                rh = list_entry(el, JSOSRWHandler, link);
                if (rh->fd == 0 && !JS_IsNull(rh->rw_func[0])) {
                    call_handler(ctx, rh->rw_func[0]);
                    /* 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 (ps->waker.handle == handles[ret]) {
                        if (handle_posted_message(rt, ctx, port))
                            goto done;
                    }
                }
            }
        }
    } else {
        Sleep(min_delay);
    }
 done:
    return 0;
}