openmct/platform/execution/src/WorkerService.js
2020-09-14 11:17:31 -07:00

93 lines
3.5 KiB
JavaScript

/*****************************************************************************
* Open MCT, Copyright (c) 2014-2020, United States Government
* as represented by the Administrator of the National Aeronautics and Space
* Administration. All rights reserved.
*
* Open MCT 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 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
* at runtime from the About dialog for additional information.
*****************************************************************************/
/**
* 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 () {
/**
* Handles the execution of WebWorkers.
* @memberof platform/execution
* @constructor
*/
function WorkerService($window, workers) {
var workerUrls = {},
sharedWorkers = {};
function addWorker(worker) {
var key = worker.key;
if (!workerUrls[key]) {
if (worker.scriptUrl) {
workerUrls[key] = [
worker.bundle.path,
worker.bundle.sources,
worker.scriptUrl
].join("/");
} else if (worker.scriptText) {
var blob = new Blob(
[worker.scriptText],
{type: 'application/javascript'}
);
workerUrls[key] = URL.createObjectURL(blob);
}
sharedWorkers[key] = worker.shared;
}
}
(workers || []).forEach(addWorker);
this.workerUrls = workerUrls;
this.sharedWorkers = sharedWorkers;
this.Worker = $window.Worker;
this.SharedWorker = $window.SharedWorker;
}
/**
* Start running a new web worker. This will run a worker
* that has been registered under the `workers` category
* of extension.
*
* This will return either a Worker or a SharedWorker,
* depending on whether a `shared` flag has been specified
* on the the extension definition for the referenced worker.
*
* @param {string} key symbolic identifier for the worker
* @returns {Worker | SharedWorker} the running Worker
*/
WorkerService.prototype.run = function (key) {
var scriptUrl = this.workerUrls[key],
Worker = this.sharedWorkers[key]
? this.SharedWorker : this.Worker;
return scriptUrl && Worker && new Worker(scriptUrl);
};
return WorkerService;
}
);