michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["LanguageDetector"];
michael@0: 
michael@0: Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: 
michael@0: XPCOMUtils.defineLazyModuleGetter(this, "Promise",
michael@0:                                   "resource://gre/modules/Promise.jsm");
michael@0: 
michael@0: const WORKER_URL = "resource:///modules/translation/cld-worker.js";
michael@0: 
michael@0: let detectionQueue = [];
michael@0: 
michael@0: let workerReady = false;
michael@0: let pendingStrings = [];
michael@0: 
michael@0: XPCOMUtils.defineLazyGetter(this, "worker", () => {
michael@0:   let worker = new Worker(WORKER_URL);
michael@0:   worker.onmessage = function(aMsg) {
michael@0:     if (aMsg.data == "ready") {
michael@0:       workerReady = true;
michael@0:       for (let string of pendingStrings)
michael@0:         worker.postMessage(string);
michael@0:       pendingStrings = [];
michael@0:     }
michael@0:     else
michael@0:       detectionQueue.shift().resolve(aMsg.data);
michael@0:   }
michael@0:   return worker;
michael@0: });
michael@0: 
michael@0: this.LanguageDetector = {
michael@0:   /**
michael@0:    * Detect the language of a given string
michael@0:    *
michael@0:    * @returns {Promise}
michael@0:    * @resolves When detection is finished, with a object containing
michael@0:    * these fields:
michael@0:    *  - 'language' (string with a language code)
michael@0:    *  - 'confident' (boolean).
michael@0:    */
michael@0:   detectLanguage: function(aString) {
michael@0:     let deferred = Promise.defer();
michael@0:     detectionQueue.push(deferred);
michael@0:     if (worker && workerReady)
michael@0:       worker.postMessage(aString);
michael@0:     else
michael@0:       pendingStrings.push(aString);
michael@0:     return deferred.promise;
michael@0:   }
michael@0: };