objj-runtime/lib/timeout.js

JavaScript (ECMAScript) and Objective-J runtime

var OS = require("os");

// setTimeout, setInterval, clearTimeout, clearInterval

// This implementation is single-threaded (like browsers) but requires a call to serviceTimeouts()

exports.setTimeout = function(callback, delay)
{
    return _scheduleTimeout(callback, delay, false);
}

exports.setInterval = function(callback, delay)
{
    return _scheduleTimeout(callback, delay, true);
}

exports.clearTimeout = function(id)
{
    if (_timeouts[id])
        _timeouts[id] = null;
}

exports.clearInterval = exports.clearTimeout;

var _nextId = 0,
    _timeouts = {},
    _pendingTimeouts = [];

var _scheduleTimeout = function(callback, delay, repeat)
{
    var date = new Date(new Date().getTime() + delay);

    if (typeof callback == "function")
        var func = callback;
    else if (typeof callback == "string")
        var func = new Function(callback);
    else
        return;

    var timeout = {
        callback: func,
        date: date,
        repeat: repeat,
        interval: delay,
        id : _nextId++
    }

    _timeouts[timeout.id] = timeout;
    _pendingTimeouts.push(timeout);

    return timeout.id;
}

exports.serviceTimeouts = function()
{
    while (_pendingTimeouts.length > 0)
    {
        _pendingTimeouts = _pendingTimeouts.sort(function (a,b) { return a.date - b.date; });

        var timeout = _pendingTimeouts.shift();
        if (_timeouts[timeout.id])
        {
            var wait = timeout.date - new Date();

            if (wait > 0)
            {
                OS.sleep(wait / 1000)
            }

            // perform the callback
            timeout.callback();

            // if its an interval, reschedule it, otherwise clear it
            if (timeout.repeat)
            {
                var now = new Date(),
                    proposed = new Date(timeout.date.getTime() + timeout.interval);
                timeout.date = (proposed < now) ? now : proposed;
                _pendingTimeouts.push(timeout);
            }
            else
                _timeouts[timeout.id] = null;
        }
    }
}