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/* ***** 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;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
// The minimum and maximum integers that can be set as preferences.
// The range of valid values is narrower than the range of valid JS values
// because the native preferences code treats integers as NSPR PRInt32s,
// which are 32-bit signed integers on all platforms.
const MAX_INT = Math.pow(2, 31) - 1;
const MIN_INT = -MAX_INT;
function Preferences(args) {
if (isObject(args)) {
if (args.branch)
this._prefBranch = args.branch;
if (args.site)
this._site = args.site;
}
else if (args)
this._prefBranch = args;
}
Preferences.prototype = {
/**
* Get the value of a pref, if any; otherwise return the default value.
*
* @param prefName {String|Array}
* the pref to get, or an array of prefs to get
*
* @param defaultValue
* the default value, if any, for prefs that don't have one
*
* @returns the value of the pref, if any; otherwise the default value
*/
get: function(prefName, defaultValue) {
if (isArray(prefName))
return prefName.map(function(v) this.get(v, defaultValue), this);
if (this._site)
return this._siteGet(prefName, defaultValue);
else
return this._get(prefName, defaultValue);
},
_get: function(prefName, defaultValue) {
switch (this._prefSvc.getPrefType(prefName)) {
case Ci.nsIPrefBranch.PREF_STRING:
return this._prefSvc.getComplexValue(prefName, Ci.nsISupportsString).data;
case Ci.nsIPrefBranch.PREF_INT:
return this._prefSvc.getIntPref(prefName);
case Ci.nsIPrefBranch.PREF_BOOL:
return this._prefSvc.getBoolPref(prefName);
case Ci.nsIPrefBranch.PREF_INVALID:
return defaultValue;
default:
// This should never happen.
throw "Error getting pref " + prefName + "; its value's type is " +
this._prefSvc.getPrefType(prefName) + ", which I don't know " +
"how to handle.";
}
},
_siteGet: function(prefName, defaultValue) {
let value = this._contentPrefSvc.getPref(this._site, this._prefBranch + prefName);
return typeof value != "undefined" ? value : defaultValue;
},
/**
* Set a preference to a value.
*
* You can set multiple prefs by passing an object as the only parameter.
* In that case, this method will treat the properties of the object
* as preferences to set, where each property name is the name of a pref
* and its corresponding property value is the value of the pref.
*
* @param prefName {String|Object}
* the name of the pref to set; or an object containing a set
* of prefs to set
*
* @param prefValue {String|Number|Boolean}
* the value to which to set the pref
*
* Note: Preferences cannot store non-integer numbers or numbers outside
* the signed 32-bit range -(2^31-1) to 2^31-1, If you have such a number,
* store it as a string by calling toString() on the number before passing
* it to this method, i.e.:
* Preferences.set("pi", 3.14159.toString())
* Preferences.set("big", Math.pow(2, 31).toString()).
*/
set: function(prefName, prefValue) {
if (isObject(prefName)) {
for (let [name, value] in Iterator(prefName))
this.set(name, value);
return;
}
if (this._site)
this._siteSet(prefName, prefValue);
else
this._set(prefName, prefValue);
},
_set: function(prefName, prefValue) {
let prefType;
if (typeof prefValue != "undefined" && prefValue != null)
prefType = prefValue.constructor.name;
switch (prefType) {
case "String":
{
let string = Cc["@mozilla.org/supports-string;1"].
createInstance(Ci.nsISupportsString);
string.data = prefValue;
this._prefSvc.setComplexValue(prefName, Ci.nsISupportsString, string);
}
break;
case "Number":
// We throw if the number is outside the range, since the result
// will never be what the consumer wanted to store, but we only warn
// if the number is non-integer, since the consumer might not mind
// the loss of precision.
if (prefValue > MAX_INT || prefValue < MIN_INT)
throw("you cannot set the " + prefName + " pref to the number " +
prefValue + ", as number pref values must be in the signed " +
"32-bit integer range -(2^31-1) to 2^31-1. To store numbers " +
"outside that range, store them as strings.");
this._prefSvc.setIntPref(prefName, prefValue);
if (prefValue % 1 != 0)
Cu.reportError("Warning: setting the " + prefName + " pref to the " +
"non-integer number " + prefValue + " converted it " +
"to the integer number " + this.get(prefName) +
"; to retain fractional precision, store non-integer " +
"numbers as strings.");
break;
case "Boolean":
this._prefSvc.setBoolPref(prefName, prefValue);
break;
default:
throw "can't set pref " + prefName + " to value '" + prefValue +
"'; it isn't a String, Number, or Boolean";
}
},
_siteSet: function(prefName, prefValue) {
this._contentPrefSvc.setPref(this._site, this._prefBranch + prefName, prefValue);
},
/**
* Whether or not the given pref has a value. This is different from isSet
* because it returns true whether the value of the pref is a default value
* or a user-set value, while isSet only returns true if the value
* is a user-set value.
*
* @param prefName {String|Array}
* the pref to check, or an array of prefs to check
*
* @returns {Boolean|Array}
* whether or not the pref has a value; or, if the caller provided
* an array of pref names, an array of booleans indicating whether
* or not the prefs have values
*/
has: function(prefName) {
if (isArray(prefName))
return prefName.map(this.has, this);
if (this._site)
return this._siteHas(prefName);
else
return this._has(prefName);
},
_has: function(prefName) {
return (this._prefSvc.getPrefType(prefName) != Ci.nsIPrefBranch.PREF_INVALID);
},
_siteHas: function(prefName) {
return this._contentPrefSvc.hasPref(this._site, this._prefBranch + prefName);
},
/**
* Whether or not the given pref has a user-set value. This is different
* from |has| because it returns true only if the value of the pref is a user-
* set value, while |has| returns true if the value of the pref is a default
* value or a user-set value.
*
* @param prefName {String|Array}
* the pref to check, or an array of prefs to check
*
* @returns {Boolean|Array}
* whether or not the pref has a user-set value; or, if the caller
* provided an array of pref names, an array of booleans indicating
* whether or not the prefs have user-set values
*/
isSet: function(prefName) {
if (isArray(prefName))
return prefName.map(this.isSet, this);
return (this.has(prefName) && this._prefSvc.prefHasUserValue(prefName));
},
/**
* Whether or not the given pref has a user-set value. Use isSet instead,
* which is equivalent.
* @deprecated
*/
modified: function(prefName) { return this.isSet(prefName) },
reset: function(prefName) {
if (isArray(prefName)) {
prefName.map(function(v) this.reset(v), this);
return;
}
if (this._site)
this._siteReset(prefName);
else
this._reset(prefName);
},
_reset: function(prefName) {
try {
this._prefSvc.clearUserPref(prefName);
}
catch(ex) {
// The pref service throws NS_ERROR_UNEXPECTED when the caller tries
// to reset a pref that doesn't exist or is already set to its default
// value. This interface fails silently in those cases, so callers
// can unconditionally reset a pref without having to check if it needs
// resetting first or trap exceptions after the fact. It passes through
// other exceptions, however, so callers know about them, since we don't
// know what other exceptions might be thrown and what they might mean.
if (ex.result != Cr.NS_ERROR_UNEXPECTED)
throw ex;
}
},
_siteReset: function(prefName) {
return this._contentPrefSvc.removePref(this._site, this._prefBranch + prefName);
},
/**
* Lock a pref so it can't be changed.
*
* @param prefName {String|Array}
* the pref to lock, or an array of prefs to lock
*/
lock: function(prefName) {
if (isArray(prefName))
prefName.map(this.lock, this);
this._prefSvc.lockPref(prefName);
},
/**
* Unlock a pref so it can be changed.
*
* @param prefName {String|Array}
* the pref to lock, or an array of prefs to lock
*/
unlock: function(prefName) {
if (isArray(prefName))
prefName.map(this.unlock, this);
this._prefSvc.unlockPref(prefName);
},
/**
* Whether or not the given pref is locked against changes.
*
* @param prefName {String|Array}
* the pref to check, or an array of prefs to check
*
* @returns {Boolean|Array}
* whether or not the pref has a user-set value; or, if the caller
* provided an array of pref names, an array of booleans indicating
* whether or not the prefs have user-set values
*/
locked: function(prefName) {
if (isArray(prefName))
return prefName.map(this.locked, this);
return this._prefSvc.prefIsLocked(prefName);
},
/**
* Start observing a pref.
*
* The callback can be a function or any object that implements nsIObserver.
* When the callback is a function and thisObject is provided, it gets called
* as a method of thisObject.
*
* @param prefName {String}
* the name of the pref to observe
*
* @param callback {Function|Object}
* the code to notify when the pref changes;
*
* @param thisObject {Object} [optional]
* the object to use as |this| when calling a Function callback;
*
* @returns the wrapped observer
*/
observe: function(prefName, callback, thisObject) {
let fullPrefName = this._prefBranch + (prefName || "");
let observer = new PrefObserver(fullPrefName, callback, thisObject);
Preferences._prefSvc.addObserver(fullPrefName, observer, true);
observers.push(observer);
return observer;
},
/**
* Stop observing a pref.
*
* You must call this method with the same prefName, callback, and thisObject
* with which you originally registered the observer. However, you don't have
* to call this method on the same exact instance of Preferences; you can call
* it on any instance. For example, the following code first starts and then
* stops observing the "foo.bar.baz" preference:
*
* let observer = function() {...};
* Preferences.observe("foo.bar.baz", observer);
* new Preferences("foo.bar.").ignore("baz", observer);
*
* @param prefName {String}
* the name of the pref being observed
*
* @param callback {Function|Object}
* the code being notified when the pref changes
*
* @param thisObject {Object} [optional]
* the object being used as |this| when calling a Function callback
*/
ignore: function(prefName, callback, thisObject) {
let fullPrefName = this._prefBranch + (prefName || "");
// This seems fairly inefficient, but I'm not sure how much better we can
// make it. We could index by fullBranch, but we can't index by callback
// or thisObject, as far as I know, since the keys to JavaScript hashes
// (a.k.a. objects) can apparently only be primitive values.
let [observer] = observers.filter(function(v) v.prefName == fullPrefName &&
v.callback == callback &&
v.thisObject == thisObject);
if (observer) {
Preferences._prefSvc.removeObserver(fullPrefName, observer);
observers.splice(observers.indexOf(observer), 1);
}
},
resetBranch: function(prefBranch) {
try {
this._prefSvc.resetBranch(prefBranch);
}
catch(ex) {
// The current implementation of nsIPrefBranch in Mozilla
// doesn't implement resetBranch, so we do it ourselves.
if (ex.result == Cr.NS_ERROR_NOT_IMPLEMENTED)
this.reset(this._prefSvc.getChildList(prefBranch, []));
else
throw ex;
}
},
/**
* The branch of the preferences tree to which this instance provides access.
* @private
*/
_prefBranch: "",
site: function(site) {
if (!(site instanceof Ci.nsIURI))
site = this._ioSvc.newURI("http://" + site, null, null);
return new Preferences({ branch: this._prefBranch, site: site });
},
/**
* Preferences Service
* @private
*/
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;
},
/**
* IO Service
* @private
*/
get _ioSvc() {
let ioSvc = Cc["@mozilla.org/network/io-service;1"].
getService(Ci.nsIIOService);
this.__defineGetter__("_ioSvc", function() ioSvc);
return this._ioSvc;
},
/**
* Site Preferences Service
* @private
*/
get _contentPrefSvc() {
let contentPrefSvc = Cc["@mozilla.org/content-pref/service;1"].
getService(Ci.nsIContentPrefService);
this.__defineGetter__("_contentPrefSvc", function() contentPrefSvc);
return this._contentPrefSvc;
}
};
// 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;
/**
* A cache of pref observers.
*
* We use this to remove observers when a caller calls Preferences::ignore.
*
* All Preferences instances share this object, because we want callers to be
* able to remove an observer using a different Preferences object than the one
* with which they added it. That means we have to identify the observers
* in this object by their complete pref name, not just their name relative to
* the root branch of the Preferences object with which they were created.
*/
let observers = [];
function PrefObserver(prefName, callback, thisObject) {
this.prefName = prefName;
this.callback = callback;
this.thisObject = thisObject;
}
PrefObserver.prototype = {
QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
observe: function(subject, topic, data) {
// The pref service only observes whole branches, but we only observe
// individual preferences, so we check here that the pref that changed
// is the exact one we're observing (and not some sub-pref on the branch).
if (data != this.prefName)
return;
if (typeof this.callback == "function") {
let prefValue = Preferences.get(this.prefName);
if (this.thisObject)
this.callback.call(this.thisObject, prefValue);
else
this.callback(prefValue);
}
else // typeof this.callback == "object" (nsIObserver)
this.callback.observe(subject, topic, data);
}
};
function isArray(val) {
// We can't check for |val.constructor == Array| here, since the value
// might be from a different context whose Array constructor is not the same
// as ours, so instead we match based on the name of the constructor.
return (typeof val != "undefined" && val != null && typeof val == "object" &&
val.constructor.name == "Array");
}
function isObject(val) {
// We can't check for |val.constructor == Object| here, since the value
// might be from a different context whose Object constructor is not the same
// as ours, so instead we match based on the name of the constructor.
return (typeof val != "undefined" && val != null && typeof val == "object" &&
val.constructor.name == "Object");
}
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