blob: 272729cab0b08766f251b75766afb6c13de966fe (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
'use strict';
var SettingsListener = {
/* Timer to remove the lock. */
_timer: null,
/* lock stores here */
_lock: null,
/**
* getSettingsLock: create a lock or retrieve one that we saved.
* mozSettings.createLock() is expensive and lock should be reused
* whenever possible.
*/
getSettingsLock: function sl_getSettingsLock() {
// Each time there is a getSettingsLock call, we pospone the removal
clearTimeout(this._timer);
this._timer = setTimeout((function removeLock() {
this._lock = null;
}).bind(this), 0);
// If there is a lock present we return that
if (this._lock) {
return this._lock;
}
// If there isn't we return one.
var settings = window.navigator.mozSettings;
return (this._lock = settings.createLock());
},
observe: function sl_observe(name, defaultValue, callback) {
var settings = window.navigator.mozSettings;
if (!settings) {
window.setTimeout(function() { callback(defaultValue); });
return;
}
var req;
try {
req = this.getSettingsLock().get(name);
} catch (e) {
// It is possible (but rare) for getSettingsLock() to return
// a SettingsLock object that is no longer valid.
// Until https://bugzilla.mozilla.org/show_bug.cgi?id=793239
// is fixed, we just catch the resulting exception and try
// again with a fresh lock
console.warn('Stale lock in settings_listener.js.',
'See https://bugzilla.mozilla.org/show_bug.cgi?id=793239');
this._lock = null;
req = this.getSettingsLock().get(name);
}
req.addEventListener('success', (function onsuccess() {
callback(typeof(req.result[name]) != 'undefined' ?
req.result[name] : defaultValue);
}));
settings.addObserver(name, function settingChanged(evt) {
callback(evt.settingValue);
});
}
};
|
