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dom/settings/SettingsChangeNotifier.jsm@97036ab72558 (annotated)

dom/settings/SettingsChangeNotifier.jsm

Tue, 06 Jan 2015 21:39:09 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Tue, 06 Jan 2015 21:39:09 +0100

branch

TOR_BUG_9701

changeset 8

97036ab72558

permissions

-rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	/* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	2	* License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0	3	* You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	4
michael@0	5	"use strict"
michael@0	6
michael@0	7	const DEBUG = false;
michael@0	8	function debug(s) {
michael@0	9	if (DEBUG) dump("-*- SettingsChangeNotifier: " + s + "\n");
michael@0	10	}
michael@0	11
michael@0	12	const Cu = Components.utils;
michael@0	13	const Cc = Components.classes;
michael@0	14	const Ci = Components.interfaces;
michael@0	15
michael@0	16	this.EXPORTED_SYMBOLS = ["SettingsChangeNotifier"];
michael@0	17
michael@0	18	Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0	19	Cu.import("resource://gre/modules/Services.jsm");
michael@0	20
michael@0	21	const kXpcomShutdownObserverTopic = "xpcom-shutdown";
michael@0	22	const kMozSettingsChangedObserverTopic = "mozsettings-changed";
michael@0	23	const kFromSettingsChangeNotifier = "fromSettingsChangeNotifier";
michael@0	24
michael@0	25	XPCOMUtils.defineLazyServiceGetter(this, "ppmm",
michael@0	26	"@mozilla.org/parentprocessmessagemanager;1",
michael@0	27	"nsIMessageBroadcaster");
michael@0	28
michael@0	29	this.SettingsChangeNotifier = {
michael@0	30	init: function() {
michael@0	31	if (DEBUG) debug("init");
michael@0	32	this.children = [];
michael@0	33	this._messages = ["Settings:Changed", "Settings:RegisterForMessages", "child-process-shutdown"];
michael@0	34	this._messages.forEach((function(msgName) {
michael@0	35	ppmm.addMessageListener(msgName, this);
michael@0	36	}).bind(this));
michael@0	37
michael@0	38	Services.obs.addObserver(this, kXpcomShutdownObserverTopic, false);
michael@0	39	Services.obs.addObserver(this, kMozSettingsChangedObserverTopic, false);
michael@0	40	},
michael@0	41
michael@0	42	observe: function(aSubject, aTopic, aData) {
michael@0	43	if (DEBUG) debug("observe");
michael@0	44	switch (aTopic) {
michael@0	45	case kXpcomShutdownObserverTopic:
michael@0	46	this._messages.forEach((function(msgName) {
michael@0	47	ppmm.removeMessageListener(msgName, this);
michael@0	48	}).bind(this));
michael@0	49	Services.obs.removeObserver(this, kXpcomShutdownObserverTopic);
michael@0	50	Services.obs.removeObserver(this, kMozSettingsChangedObserverTopic);
michael@0	51	ppmm = null;
michael@0	52	break;
michael@0	53	case kMozSettingsChangedObserverTopic:
michael@0	54	{
michael@0	55	let setting = JSON.parse(aData);
michael@0	56	// To avoid redundantly broadcasting settings-changed events that are
michael@0	57	// just requested from content processes themselves, skip the observer
michael@0	58	// messages that are notified from the internal SettingsChangeNotifier.
michael@0	59	if (setting.message && setting.message === kFromSettingsChangeNotifier)
michael@0	60	return;
michael@0	61	this.broadcastMessage("Settings:Change:Return:OK",
michael@0	62	{ key: setting.key, value: setting.value });
michael@0	63	break;
michael@0	64	}
michael@0	65	default:
michael@0	66	if (DEBUG) debug("Wrong observer topic: " + aTopic);
michael@0	67	break;
michael@0	68	}
michael@0	69	},
michael@0	70
michael@0	71	broadcastMessage: function broadcastMessage(aMsgName, aContent) {
michael@0	72	if (DEBUG) debug("Broadast");
michael@0	73	this.children.forEach(function(msgMgr) {
michael@0	74	msgMgr.sendAsyncMessage(aMsgName, aContent);
michael@0	75	});
michael@0	76	},
michael@0	77
michael@0	78	receiveMessage: function(aMessage) {
michael@0	79	if (DEBUG) debug("receiveMessage");
michael@0	80	let msg = aMessage.data;
michael@0	81	let mm = aMessage.target;
michael@0	82	switch (aMessage.name) {
michael@0	83	case "Settings:Changed":
michael@0	84	if (!aMessage.target.assertPermission("settings-write")) {
michael@0	85	Cu.reportError("Settings message " + msg.name +
michael@0	86	" from a content process with no 'settings-write' privileges.");
michael@0	87	return null;
michael@0	88	}
michael@0	89	this.broadcastMessage("Settings:Change:Return:OK",
michael@0	90	{ key: msg.key, value: msg.value });
michael@0	91	Services.obs.notifyObservers(this, kMozSettingsChangedObserverTopic,
michael@0	92	JSON.stringify({
michael@0	93	key: msg.key,
michael@0	94	value: msg.value,
michael@0	95	message: kFromSettingsChangeNotifier
michael@0	96	}));
michael@0	97	break;
michael@0	98	case "Settings:RegisterForMessages":
michael@0	99	if (!aMessage.target.assertPermission("settings-read")) {
michael@0	100	Cu.reportError("Settings message " + msg.name +
michael@0	101	" from a content process with no 'settings-read' privileges.");
michael@0	102	return null;
michael@0	103	}
michael@0	104	if (DEBUG) debug("Register!");
michael@0	105	if (this.children.indexOf(mm) == -1) {
michael@0	106	this.children.push(mm);
michael@0	107	}
michael@0	108	break;
michael@0	109	case "child-process-shutdown":
michael@0	110	if (DEBUG) debug("Unregister");
michael@0	111	let index;
michael@0	112	if ((index = this.children.indexOf(mm)) != -1) {
michael@0	113	if (DEBUG) debug("Unregister index: " + index);
michael@0	114	this.children.splice(index, 1);
michael@0	115	}
michael@0	116	break;
michael@0	117	default:
michael@0	118	if (DEBUG) debug("Wrong message: " + aMessage.name);
michael@0	119	}
michael@0	120	}
michael@0	121	}
michael@0	122
michael@0	123	SettingsChangeNotifier.init();