new implementation of Preferences module

Preferences.js

@@ -0,0 +1,150 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Preferences.
+ *
+ * The Initial Developer of the Original Code is Mozilla.
+ * Portions created by the Initial Developer are Copyright (C) 2008
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Myk Melez <myk@mozilla.org>
+ *   Daniel Aquino <mr.danielaquino@gmail.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+let EXPORTED_SYMBOLS = ["Preferences"];
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cr = Components.results;
+const Cu = Components.utils;
+
+function Preferences(prefBranch) {
+  if (prefBranch)
+    this._prefBranch = prefBranch;
+}
+
+Preferences.prototype = {
+  _prefBranch: "",
+
+  // Preferences Service
+
+  get _prefSvc() {
+    let prefSvc = Cc["@mozilla.org/preferences-service;1"].
+                  getService(Ci.nsIPrefService).
+                  getBranch(this._prefBranch).
+                  QueryInterface(Ci.nsIPrefBranch2);
+    this.__defineGetter__("_prefSvc", function() prefSvc);
+    return this._prefSvc;
+  },
+
+  /**
+    * Get the value of a pref, if any; otherwise return the default value.
+    *
+    * @param   prefName      the name of the pref to get
+    * @param   defaultValue  the default value, if any
+    *
+    * @returns the value of the pref, if any; otherwise the default value
+    */
+  get: function(prefName, defaultValue) {
+    // We can't check for |prefName.constructor == Array| here, since we have
+    // a different global object, so we check the constructor name instead.
+    if (typeof prefName == "object" && prefName.constructor.name == Array.name)
+      return prefName.map(function(v) this.get(v), this);
+
+    try {
+      switch (this._prefSvc.getPrefType(prefName)) {
+        case Ci.nsIPrefBranch.PREF_STRING:
+          return this._prefSvc.getCharPref(prefName);
+        case Ci.nsIPrefBranch.PREF_INT:
+          return this._prefSvc.getIntPref(prefName);
+        case Ci.nsIPrefBranch.PREF_BOOL:
+          return this._prefSvc.getBoolPref(prefName);
+      }
+    }
+    catch (ex) {}
+  
+    return defaultValue;
+  },
+
+  set: function(prefName, prefValue) {
+    // We can't check for |prefName.constructor == Object| here, since we have
+    // a different global object, so we check the constructor name instead.
+    if (typeof prefName == "object" && prefName.constructor.name == Object.name)
+      for (let [name, value] in Iterator(prefName))
+        this.set(name, value);
+    else {
+      switch (typeof prefValue) {
+        case "number":
+          this._prefSvc.setIntPref(prefName, prefValue);
+          break;
+        case "boolean":
+          this._prefSvc.setBoolPref(prefName, prefValue);
+          break;
+        case "string":
+        default:
+          this._prefSvc.setCharPref(prefName, prefValue);
+          break;
+      }
+    }
+  },
+
+  // FIXME: make the methods below accept an array of pref names.
+
+  has: function(prefName) {
+    return (this._prefSvc.getPrefType(prefName) != this._prefSvc.PREF_INVALID);
+  },
+
+  modified: function(prefName) {
+    return (this.has(prefName) && this._prefSvc.prefHasUserValue(prefName));
+  },
+
+  locked: function(prefName) {
+    return this._prefSvc.isLocked(prefName);
+  },
+
+  lock: function(prefName) {
+    this._prefSvc.lockPref(prefName);
+  },
+
+  unlock: function(prefName) {
+    this._prefSvc.unlockPref(prefName);
+  },
+
+  reset: function(prefName) {
+    this._prefSvc.clearUserPref(prefName);
+  },
+
+  resetBranch: function(prefBranch) {
+    this._prefSvc.resetBranch(prefBranch);
+  }
+
+};
+
+// Give the constructor the same prototype as its instances, so users can access
+// preferences directly via the constructor without having to create an instance
+// first.
+Preferences.__proto__ = Preferences.prototype;