gecko-dev/b2g/components/Frames.jsm

123 строки
3.2 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
'use strict';
this.EXPORTED_SYMBOLS = ['Frames'];
const Cu = Components.utils;
const Ci = Components.interfaces;
Cu.import('resource://gre/modules/Services.jsm');
Cu.import('resource://gre/modules/SystemAppProxy.jsm');
const listeners = [];
const Observer = {
// Save a map of (MessageManager => Frame) to be able to dispatch
// the FrameDestroyed event with a frame reference.
_frames: new Map(),
start: function () {
Services.obs.addObserver(this, 'remote-browser-shown', false);
Services.obs.addObserver(this, 'inprocess-browser-shown', false);
Services.obs.addObserver(this, 'message-manager-close', false);
SystemAppProxy.getFrames().forEach(frame => {
let mm = frame.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader.messageManager;
this._frames.set(mm, frame);
});
},
stop: function () {
Services.obs.removeObserver(this, 'remote-browser-shown');
Services.obs.removeObserver(this, 'inprocess-browser-shown');
Services.obs.removeObserver(this, 'message-manager-close');
this._frames.clear();
},
observe: function (subject, topic, data) {
switch(topic) {
// Listen for frame creation in OOP (device) as well as in parent process (b2g desktop)
case 'remote-browser-shown':
case 'inprocess-browser-shown':
let frameLoader = subject;
// get a ref to the app <iframe>
frameLoader.QueryInterface(Ci.nsIFrameLoader);
let frame = frameLoader.ownerElement;
let mm = frame.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader.messageManager;
this.onMessageManagerCreated(mm, frame);
break;
// Every time an iframe is destroyed, its message manager also is
case 'message-manager-close':
this.onMessageManagerDestroyed(subject);
break;
}
},
onMessageManagerCreated: function (mm, frame) {
this._frames.set(mm, frame);
listeners.forEach(function (listener) {
try {
listener.onFrameCreated(frame);
} catch(e) {
dump('Exception while calling Frames.jsm listener:' + e + '\n' +
e.stack + '\n');
}
});
},
onMessageManagerDestroyed: function (mm) {
let frame = this._frames.get(mm);
if (!frame) {
// We received an event for an unknown message manager
return;
}
this._frames.delete(mm);
listeners.forEach(function (listener) {
try {
listener.onFrameDestroyed(frame);
} catch(e) {
dump('Exception while calling Frames.jsm listener:' + e + '\n' +
e.stack + '\n');
}
});
}
};
var Frames = this.Frames = {
list: () => SystemAppProxy.getFrames(),
addObserver: function (listener) {
if (listeners.indexOf(listener) !== -1) {
return;
}
listeners.push(listener);
if (listeners.length == 1) {
Observer.start();
}
},
removeObserver: function (listener) {
let idx = listeners.indexOf(listener);
if (idx !== -1) {
listeners.splice(idx, 1);
}
if (listeners.length === 0) {
Observer.stop();
}
}
};