mirror of
https://github.com/moparisthebest/FireTray
synced 2024-11-15 21:35:01 -05:00
51 lines
1.5 KiB
JavaScript
51 lines
1.5 KiB
JavaScript
/* -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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// https://developer.mozilla.org/en/Code_snippets/Preferences
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var EXPORTED_SYMBOLS = [ "PrefListener" ];
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const Cc = Components.classes;
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const Ci = Components.interfaces;
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const Cu = Components.utils;
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/**
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* @constructor
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*
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* @param {string} branch_name
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* @param {Function} callback must have the following arguments:
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* branch, pref_leaf_name
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*/
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function PrefListener(branch_name, callback) {
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// Keeping a reference to the observed preference branch or it will get
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// garbage collected.
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var prefService = Components.classes["@mozilla.org/preferences-service;1"]
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.getService(Components.interfaces.nsIPrefService);
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this._branch = prefService.getBranch(branch_name);
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this._branch.QueryInterface(Ci.nsIPrefBranch);
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this._callback = callback;
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}
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PrefListener.prototype.observe = function(subject, topic, data) {
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if (topic == 'nsPref:changed')
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this._callback(this._branch, data);
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};
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/**
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* @param {boolean=} trigger if true triggers the registered function
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* on registration, that is, when this method is called.
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*/
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PrefListener.prototype.register = function(trigger) {
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this._branch.addObserver('', this, false);
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if (trigger) {
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let that = this;
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this._branch.getChildList('', {}).
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forEach(function (pref_leaf_name)
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{ that._callback(that._branch, pref_leaf_name); });
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}
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};
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PrefListener.prototype.unregister = function() {
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if (this._branch)
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this._branch.removeObserver('', this);
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};
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