preferences.js revision 731df977c0511bca2206b5f333555b1205ff1f43 
1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5cr.define('options', function() {
6
7  /////////////////////////////////////////////////////////////////////////////
8  // Preferences class:
9
10  /**
11   * Preferences class manages access to Chrome profile preferences.
12   * @constructor
13   */
14  function Preferences() {
15  }
16
17  cr.addSingletonGetter(Preferences);
18
19  /**
20   * Extracts preference value.
21   * @param {Object} dict Map of preference values passed to fetchPrefs
22   *     callback.
23   * @param {string} name Preference name.
24   * @return preference value.
25   */
26  Preferences.getPref = function (dict, name) {
27    var parts = name.split('.');
28    var cur = dict;
29    for (var part; part = parts.shift(); ) {
30      if (cur[part]) {
31        cur = cur[part];
32      } else {
33        return null;
34      }
35    }
36    return cur;
37  };
38
39  /**
40   * Sets value of a boolean preference.
41   * and signals its changed value.
42   * @param {string} name Preference name.
43   * @param {boolean} value New preference value.
44   * @param {string} metric User metrics identifier.
45   */
46  Preferences.setBooleanPref = function (name, value, metric) {
47    var arguments = [name, value ? 'true' : 'false'];
48    if (metric != undefined) arguments.push(metric);
49    chrome.send('setBooleanPref', arguments);
50  };
51
52  /**
53   * Sets value of an integer preference.
54   * and signals its changed value.
55   * @param {string} name Preference name.
56   * @param {number} value New preference value.
57   * @param {string} metric User metrics identifier.
58   */
59  Preferences.setIntegerPref = function(name, value, metric) {
60    var arguments = [name, String(value)];
61    if (metric != undefined) arguments.push(metric);
62    chrome.send('setIntegerPref', arguments);
63  };
64
65  /**
66   * Sets value of a string preference.
67   * and signals its changed value.
68   * @param {string} name Preference name.
69   * @param {string} value New preference value.
70   * @param {string} metric User metrics identifier.
71   */
72  Preferences.setStringPref = function(name, value, metric) {
73    var arguments = [name, value];
74    if (metric != undefined) arguments.push(metric);
75    chrome.send('setStringPref', arguments);
76  };
77
78  /**
79   * Sets value of a JSON preference.
80   * and signals its changed value.
81   * @param {string} name Preference name.
82   * @param {string} value New preference value.
83   * @param {string} metric User metrics identifier.
84   */
85  Preferences.setObjectPref = function(name, value, metric) {
86    var arguments = [name, JSON.stringify(value)];
87    if (metric != undefined) arguments.push(metric);
88    chrome.send('setObjectPref', arguments);
89  };
90
91  /**
92   * Clears value of a JSON preference.
93   * @param {string} name Preference name.
94   * @param {string} metric User metrics identifier.
95   */
96  Preferences.clearPref = function(name, metric) {
97    var arguments = [name];
98    if (metric != undefined) arguments.push(metric);
99    chrome.send('clearPref', arguments);
100  };
101
102  Preferences.prototype = {
103    __proto__: cr.EventTarget.prototype,
104
105    // Map of registered preferences.
106    registeredPreferences_: {},
107
108    /**
109     * Adds an event listener to the target.
110     * @param {string} type The name of the event.
111     * @param {!Function|{handleEvent:Function}} handler The handler for the
112     *     event. This is called when the event is dispatched.
113     */
114    addEventListener: function(type, handler) {
115      cr.EventTarget.prototype.addEventListener.call(this, type, handler);
116      this.registeredPreferences_[type] = true;
117    },
118
119    /**
120     * Initializes preference reading and change notifications.
121     */
122    initialize: function() {
123      var params1 = ['Preferences.prefsFetchedCallback'];
124      var params2 = ['Preferences.prefsChangedCallback'];
125      for (var prefName in this.registeredPreferences_) {
126        params1.push(prefName);
127        params2.push(prefName);
128      }
129      chrome.send('fetchPrefs', params1);
130      chrome.send('observePrefs', params2);
131    },
132
133    /**
134     * Helper function for flattening of dictionary passed via fetchPrefs
135     * callback.
136     * @param {string} prefix Preference name prefix.
137     * @param {object} dict Map with preference values.
138     */
139    flattenMapAndDispatchEvent_: function(prefix, dict) {
140      for (var prefName in dict) {
141        if (typeof dict[prefName] == 'object' &&
142            !this.registeredPreferences_[prefix + prefName]) {
143          this.flattenMapAndDispatchEvent_(prefix + prefName + '.',
144              dict[prefName]);
145        } else {
146          var event = new cr.Event(prefix + prefName);
147          event.value = dict[prefName];
148          this.dispatchEvent(event);
149        }
150      }
151    }
152  };
153
154  /**
155   * Callback for fetchPrefs method.
156   * @param {object} dict Map of fetched property values.
157   */
158  Preferences.prefsFetchedCallback = function(dict) {
159    Preferences.getInstance().flattenMapAndDispatchEvent_('', dict);
160  };
161
162  /**
163   * Callback for observePrefs method.
164   * @param {array} notification An array defining changed preference values.
165   * notification[0] contains name of the change preference while its new value
166   * is stored in notification[1].
167   */
168  Preferences.prefsChangedCallback = function(notification) {
169    var event = new cr.Event(notification[0]);
170    event.value = notification[1];
171    Preferences.getInstance().dispatchEvent(event);
172  };
173
174  // Export
175  return {
176    Preferences: Preferences
177  };
178
179});
180
181