openmct/platform/execution/src/WorkerService.js

/*****************************************************************************
 * Open MCT Web, Copyright (c) 2014-2015, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT Web is licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * Open MCT Web includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
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 *****************************************************************************/
/*global define*/


/**
 * This bundle contains services for managing the flow of execution,
 * such as support for running web workers on background threads.
 * @namespace platform/execution
 */
define(
    [],
    function () {
        "use strict";

        /**
         * Handles the execution of WebWorkers.
         * @memberof platform/execution
         * @constructor
         */
        function WorkerService($window, workers) {
            var workerUrls = {};

            function addWorker(worker) {
                var key = worker.key;
                if (!workerUrls[key]) {
                    workerUrls[key] = [
                        worker.bundle.path,
                        worker.bundle.sources,
                        worker.scriptUrl
                    ].join("/");
                }
            }

            (workers || []).forEach(addWorker);
            this.workerUrls = workerUrls;
            this.Worker = $window.Worker;
        }

        /**
         * Start running a new web worker. This will run a worker
         * that has been registered under the `workers` category
         * of extension.
         *
         * @param {string} key symbolic identifier for the worker
         * @returns {Worker} the running Worker
         */
        WorkerService.prototype.run = function (key) {
            var scriptUrl = this.workerUrls[key],
                Worker = this.Worker;
            return scriptUrl && Worker && new Worker(scriptUrl);
        };

        return WorkerService;
    }
);