michael@0: // -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; js2-basic-offset: 2; js2-skip-preprocessor-directives: t; -*-
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: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["sendOrderedBroadcast"];
michael@0: 
michael@0: const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
michael@0: 
michael@0: // For adding observers.
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: Cu.import("resource://gre/modules/Messaging.jsm");
michael@0: 
michael@0: let _callbackId = 1;
michael@0: 
michael@0: /**
michael@0:  * Send an ordered broadcast to Java.
michael@0:  *
michael@0:  * Internally calls Context.sendOrderedBroadcast.
michael@0:  *
michael@0:  * action {String} should be a string with a qualified name (like
michael@0:  * org.mozilla.gecko.action) that will be broadcast.
michael@0:  *
michael@0:  * token {Object} is a piece of arbitrary data that will be given as
michael@0:  * a parameter to the callback (possibly null).
michael@0:  *
michael@0:  * callback {function} should accept three arguments: the data
michael@0:  * returned from Java as an Object; the specified token; and the
michael@0:  * specified action.
michael@0:  *
michael@0:  * permission {String} is an optional string with an Android permission
michael@0:  * that packages must have to respond to the ordered broadcast. A null
michael@0:  * value allows any package to respond. If the parameter is omitted (or
michael@0:  * {undefined}), then the intent is restricted to the current package.
michael@0:  */
michael@0: function sendOrderedBroadcast(action, token, callback, permission) {
michael@0:   let callbackId = _callbackId++;
michael@0:   let responseEvent = "OrderedBroadcast:Response:" + callbackId;
michael@0: 
michael@0:   let observer = {
michael@0:     callbackId: callbackId,
michael@0:     callback: callback,
michael@0: 
michael@0:     observe: function observe(subject, topic, data) {
michael@0:       if (topic != responseEvent) {
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       // Unregister observer as soon as possible.
michael@0:       Services.obs.removeObserver(observer, responseEvent);
michael@0: 
michael@0:       let msg = JSON.parse(data);
michael@0:       if (!msg.action || !msg.token || !msg.token.callbackId)
michael@0:         return;
michael@0: 
michael@0:       let theToken = msg.token.data;
michael@0:       let theAction = msg.action;
michael@0:       let theData = msg.data ? JSON.parse(msg.data) : null;
michael@0: 
michael@0:       let theCallback = this.callback;
michael@0:       if (!theCallback)
michael@0:         return;
michael@0: 
michael@0:       // This is called from within a notified observer, so we don't
michael@0:       // need to take special pains to catch exceptions.
michael@0:       theCallback(theData, theToken, theAction);
michael@0:     },
michael@0:   };
michael@0: 
michael@0:   Services.obs.addObserver(observer, responseEvent, false);
michael@0: 
michael@0:   sendMessageToJava({
michael@0:     type: "OrderedBroadcast:Send",
michael@0:     action: action,
michael@0:     responseEvent: responseEvent,
michael@0:     token: { callbackId: callbackId, data: token || null },
michael@0:     permission: permission,
michael@0:   });
michael@0: };