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/* 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';
module.metadata = {
"stability": "unstable"
};
const { Cc, Ci } = require('chrome');
const { Class } = require('../core/heritage');
const { EventTarget } = require('../event/target');
const { Branch } = require('./service');
const { emit, off } = require('../event/core');
const { when: unload } = require('../system/unload');
const prefTargetNS = require('../core/namespace').ns();
const PrefsTarget = Class({
extends: EventTarget,
initialize: function(options) {
options = options || {};
EventTarget.prototype.initialize.call(this, options);
let branchName = options.branchName || '';
let branch = Cc["@mozilla.org/preferences-service;1"].
getService(Ci.nsIPrefService).
getBranch(branchName).
QueryInterface(Ci.nsIPrefBranch2);
prefTargetNS(this).branch = branch;
// provides easy access to preference values
this.prefs = Branch(branchName);
// start listening to preference changes
let observer = prefTargetNS(this).observer = onChange.bind(this);
branch.addObserver('', observer, false);
// Make sure to destroy this on unload
unload(destroy.bind(this));
}
});
exports.PrefsTarget = PrefsTarget;
/* HELPERS */
function onChange(subject, topic, name) {
if (topic === 'nsPref:changed') {
emit(this, name, name);
emit(this, '', name);
}
}
function destroy() {
off(this);
// stop listening to preference changes
let branch = prefTargetNS(this).branch;
branch.removeObserver('', prefTargetNS(this).observer, false);
prefTargetNS(this).observer = null;
}
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