gecko/dom/datastore/DataStoreChangeNotifier.jsm

224 lines
7.3 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"
const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
this.EXPORTED_SYMBOLS = ["DataStoreChangeNotifier"];
function debug(s) {
//dump('DEBUG DataStoreChangeNotifier: ' + s + '\n');
}
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
XPCOMUtils.defineLazyServiceGetter(this, "ppmm",
"@mozilla.org/parentprocessmessagemanager;1",
"nsIMessageBroadcaster");
XPCOMUtils.defineLazyServiceGetter(this, "dataStoreService",
"@mozilla.org/datastore-service;1",
"nsIDataStoreService");
XPCOMUtils.defineLazyServiceGetter(this, "systemMessenger",
"@mozilla.org/system-message-internal;1",
"nsISystemMessagesInternal");
var kSysMsgOnChangeShortTimeoutSec =
Services.prefs.getIntPref("dom.datastore.sysMsgOnChangeShortTimeoutSec");
var kSysMsgOnChangeLongTimeoutSec =
Services.prefs.getIntPref("dom.datastore.sysMsgOnChangeLongTimeoutSec");
this.DataStoreChangeNotifier = {
children: [],
messages: [ "DataStore:Changed", "DataStore:RegisterForMessages",
"DataStore:UnregisterForMessages",
"child-process-shutdown" ],
// These hashes are used for storing the mapping between the datastore
// identifiers (name | owner manifest URL) and their correspondent timers.
// The object literal is defined as below:
//
// {
// "datastore name 1|owner manifest URL 1": timer1,
// "datastore name 2|owner manifest URL 2": timer2,
// ...
// }
sysMsgOnChangeShortTimers: {},
sysMsgOnChangeLongTimers: {},
init: function() {
debug("init");
this.messages.forEach((function(msgName) {
ppmm.addMessageListener(msgName, this);
}).bind(this));
Services.obs.addObserver(this, 'xpcom-shutdown', false);
},
observe: function(aSubject, aTopic, aData) {
debug("observe");
switch (aTopic) {
case 'xpcom-shutdown':
this.messages.forEach((function(msgName) {
ppmm.removeMessageListener(msgName, this);
}).bind(this));
Services.obs.removeObserver(this, 'xpcom-shutdown');
ppmm = null;
break;
default:
debug("Wrong observer topic: " + aTopic);
break;
}
},
broadcastMessage: function broadcastMessage(aData) {
debug("broadcast");
this.children.forEach(function(obj) {
if (obj.store == aData.store && obj.owner == aData.owner) {
obj.mm.sendAsyncMessage("DataStore:Changed:Return:OK", aData);
}
});
},
broadcastSystemMessage: function(aStore, aOwner) {
debug("broadcastSystemMessage");
// Clear relevant timers.
var storeKey = aStore + "|" + aOwner;
var shortTimer = this.sysMsgOnChangeShortTimers[storeKey];
if (shortTimer) {
shortTimer.cancel();
delete this.sysMsgOnChangeShortTimers[storeKey];
}
var longTimer = this.sysMsgOnChangeLongTimers[storeKey];
if (longTimer) {
longTimer.cancel();
delete this.sysMsgOnChangeLongTimers[storeKey];
}
systemMessenger.broadcastMessage("datastore-update-" + aStore,
{ owner: aOwner });
},
// Use the following logic to broadcast system messages in a moderate pattern.
// 1. When an entry is changed, start a short timer and a long timer.
// 2. If an entry is changed while the short timer is running, reset it.
// Do not reset the long timer.
// 3. Once either fires, broadcast the system message and cancel both timers.
setSystemMessageTimeout: function(aStore, aOwner) {
debug("setSystemMessageTimeout");
var storeKey = aStore + "|" + aOwner;
// Reset the short timer.
var shortTimer = this.sysMsgOnChangeShortTimers[storeKey];
if (!shortTimer) {
shortTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
this.sysMsgOnChangeShortTimers[storeKey] = shortTimer;
} else {
shortTimer.cancel();
}
shortTimer.initWithCallback({ notify: this.broadcastSystemMessage.bind(this, aStore, aOwner) },
kSysMsgOnChangeShortTimeoutSec * 1000,
Ci.nsITimer.TYPE_ONE_SHOT);
// Set the long timer if necessary.
if (!this.sysMsgOnChangeLongTimers[storeKey]) {
var longTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
this.sysMsgOnChangeLongTimers[storeKey] = longTimer;
longTimer.initWithCallback({ notify: this.broadcastSystemMessage.bind(this, aStore, aOwner) },
kSysMsgOnChangeLongTimeoutSec * 1000,
Ci.nsITimer.TYPE_ONE_SHOT);
}
},
receiveMessage: function(aMessage) {
debug("receiveMessage ");
// No check has to be done when the message is 'child-process-shutdown'.
if (aMessage.name != "child-process-shutdown") {
let principal = aMessage.principal;
if (!principal || !dataStoreService.checkPermission(principal)) {
return;
}
}
switch (aMessage.name) {
case "DataStore:Changed":
this.broadcastMessage(aMessage.data);
if (Services.prefs.getBoolPref("dom.sysmsg.enabled")) {
this.setSystemMessageTimeout(aMessage.data.store, aMessage.data.owner);
}
break;
case "DataStore:RegisterForMessages":
debug("Register!");
for (let i = 0; i < this.children.length; ++i) {
if (this.children[i].mm == aMessage.target &&
this.children[i].store == aMessage.data.store &&
this.children[i].owner == aMessage.data.owner) {
debug("Register on existing index: " + i);
this.children[i].windows.push(aMessage.data.innerWindowID);
return;
}
}
this.children.push({ mm: aMessage.target,
store: aMessage.data.store,
owner: aMessage.data.owner,
windows: [ aMessage.data.innerWindowID ]});
break;
case "DataStore:UnregisterForMessages":
debug("Unregister");
for (let i = 0; i < this.children.length; ++i) {
if (this.children[i].mm == aMessage.target) {
debug("Unregister index: " + i);
var pos = this.children[i].windows.indexOf(aMessage.data.innerWindowID);
if (pos != -1) {
this.children[i].windows.splice(pos, 1);
}
if (this.children[i].windows.length) {
continue;
}
debug("Unregister delete index: " + i);
this.children.splice(i, 1);
--i;
}
}
break;
case "child-process-shutdown":
debug("Child process shutdown");
for (let i = 0; i < this.children.length; ++i) {
if (this.children[i].mm == aMessage.target) {
debug("Unregister index: " + i);
this.children.splice(i, 1);
--i;
}
}
break;
default:
debug("Wrong message: " + aMessage.name);
}
}
}
DataStoreChangeNotifier.init();