62 lines
1.7 KiB
JavaScript
62 lines
1.7 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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'use strict';
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module.metadata = {
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"stability": "unstable"
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};
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const { Cc, Ci } = require('chrome');
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const { Class } = require('../core/heritage');
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const { EventTarget } = require('../event/target');
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const { Branch } = require('./service');
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const { emit, off } = require('../event/core');
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const { when: unload } = require('../system/unload');
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const prefTargetNS = require('../core/namespace').ns();
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const PrefsTarget = Class({
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extends: EventTarget,
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initialize: function(options) {
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options = options || {};
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EventTarget.prototype.initialize.call(this, options);
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let branchName = options.branchName || '';
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let branch = Cc["@mozilla.org/preferences-service;1"].
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getService(Ci.nsIPrefService).
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getBranch(branchName).
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QueryInterface(Ci.nsIPrefBranch2);
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prefTargetNS(this).branch = branch;
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// provides easy access to preference values
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this.prefs = Branch(branchName);
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// start listening to preference changes
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let observer = prefTargetNS(this).observer = onChange.bind(this);
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branch.addObserver('', observer, false);
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// Make sure to destroy this on unload
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unload(destroy.bind(this));
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}
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});
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exports.PrefsTarget = PrefsTarget;
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/* HELPERS */
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function onChange(subject, topic, name) {
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if (topic === 'nsPref:changed') {
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emit(this, name, name);
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emit(this, '', name);
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}
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}
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function destroy() {
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off(this);
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// stop listening to preference changes
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let branch = prefTargetNS(this).branch;
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branch.removeObserver('', prefTargetNS(this).observer, false);
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prefTargetNS(this).observer = null;
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}
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