source: gs3-extensions/web-audio/trunk/js-mad/sink.js-master/src/core/inline-worker.js@ 28388

void function (Sink) {

/**
 * Creates an inline worker using a data/blob URL, if possible.
 *
 * @static Sink
 *
 * @arg {String} script
 *
 * @return {Worker} A web worker, or null if impossible to create.
*/

var define = Object.defineProperty ? function (obj, name, value) {
    Object.defineProperty(obj, name, {
        value: value,
        configurable: true,
        writable: true
    });
} : function (obj, name, value) {
    obj[name] = value;
};

function terminate () {
    define(this, 'terminate', this._terminate);

    Sink.revokeDynURL(this._url);

    delete this._url;
    delete this._terminate;
    return this.terminate();
}

function inlineWorker (script) {
    function wrap (type, content, typeName) {
        try {
            var url = type(content, 'text/javascript');
            var worker = new Worker(url);

            define(worker, '_url', url);
            define(worker, '_terminate', worker.terminate);
            define(worker, 'terminate', terminate);

            if (inlineWorker.type) return worker;

            inlineWorker.type = typeName;
            inlineWorker.createURL = type;

            return worker;
        } catch (e) {
            return null;
        }
    }

    var createDynURL = Sink.createDynURL;

    if (!createDynURL) return null;

    var worker;

    if (inlineWorker.createURL) {
        return wrap(inlineWorker.createURL, script, inlineWorker.type);
    }

    worker = wrap(createDynURL.createBlob, script, 'blob');
    if (worker) return worker;

    worker = wrap(createDynURL.createBlobBuilder, script, 'blobbuilder');
    if (worker) return worker;

    worker = wrap(createDynURL.createData, script, 'data');

    return worker;
}

Sink.EventEmitter.call(inlineWorker);

inlineWorker.test = function () {
    inlineWorker.ready = inlineWorker.working = false;
    inlineWorker.type = '';
    inlineWorker.createURL = null;

    var worker = inlineWorker('this.onmessage=function(e){postMessage(e.data)}');
    var data = 'inlineWorker';

    function ready (success) {
        if (inlineWorker.ready) return;

        inlineWorker.ready = true;
        inlineWorker.working = success;
        inlineWorker.emit('ready', [success]);
        inlineWorker.off('ready');

        if (success && worker) {
            worker.terminate();
        }

        worker = null;
    }

    if (!worker) {
        setTimeout(function () {
            ready(false);
        }, 0);
    } else {
        worker.onmessage = function (e) {
            ready(e.data === data);
        };

        worker.postMessage(data);

        setTimeout(function () {
            ready(false);
        }, 1000);
    }
};

Sink.inlineWorker = inlineWorker;

inlineWorker.test();

}(this.Sink);