michael@0: // -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; js2-basic-offset: 2; js2-skip-preprocessor-directives: t; -*-
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["SharedPreferences"];
michael@0: 
michael@0: const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
michael@0: 
michael@0: // For adding observers.
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: Cu.import("resource://gre/modules/Messaging.jsm");
michael@0: 
michael@0: /**
michael@0:  * Create an interface to an Android SharedPreferences branch.
michael@0:  *
michael@0:  * branch {String} should be a string describing a preferences branch,
michael@0:  * like "UpdateService" or "background.data", or null to access the
michael@0:  * default preferences branch for the application.
michael@0:  */
michael@0: function SharedPreferences(branch) {
michael@0:   if (!(this instanceof SharedPreferences)) {
michael@0:     return new SharedPreferences(branch);
michael@0:   }
michael@0:   this._branch = branch || null;
michael@0:   this._observers = {};
michael@0: };
michael@0: 
michael@0: SharedPreferences.prototype = Object.freeze({
michael@0:   _set: function _set(prefs) {
michael@0:     sendMessageToJava({
michael@0:       type: "SharedPreferences:Set",
michael@0:       preferences: prefs,
michael@0:       branch: this._branch,
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   _setOne: function _setOne(prefName, value, type) {
michael@0:     let prefs = [];
michael@0:     prefs.push({
michael@0:       name: prefName,
michael@0:       value: value,
michael@0:       type: type,
michael@0:     });
michael@0:     this._set(prefs);
michael@0:   },
michael@0: 
michael@0:   setBoolPref: function setBoolPref(prefName, value) {
michael@0:     this._setOne(prefName, value, "bool");
michael@0:   },
michael@0: 
michael@0:   setCharPref: function setCharPref(prefName, value) {
michael@0:     this._setOne(prefName, value, "string");
michael@0:   },
michael@0: 
michael@0:   setIntPref: function setIntPref(prefName, value) {
michael@0:     this._setOne(prefName, value, "int");
michael@0:   },
michael@0: 
michael@0:   _get: function _get(prefs, callback) {
michael@0:     let result = null;
michael@0:     sendMessageToJava({
michael@0:       type: "SharedPreferences:Get",
michael@0:       preferences: prefs,
michael@0:       branch: this._branch,
michael@0:     }, (data) => {
michael@0:       result = data.values;
michael@0:     });
michael@0: 
michael@0:     let thread = Services.tm.currentThread;
michael@0:     while (result == null)
michael@0:       thread.processNextEvent(true);
michael@0: 
michael@0:     return result;
michael@0:   },
michael@0: 
michael@0:   _getOne: function _getOne(prefName, type) {
michael@0:     let prefs = [];
michael@0:     prefs.push({
michael@0:       name: prefName,
michael@0:       type: type,
michael@0:     });
michael@0:     let values = this._get(prefs);
michael@0:     if (values.length != 1) {
michael@0:       throw new Error("Got too many values: " + values.length);
michael@0:     }
michael@0:     return values[0].value;
michael@0:   },
michael@0: 
michael@0:   getBoolPref: function getBoolPref(prefName) {
michael@0:     return this._getOne(prefName, "bool");
michael@0:   },
michael@0: 
michael@0:   getCharPref: function getCharPref(prefName) {
michael@0:     return this._getOne(prefName, "string");
michael@0:   },
michael@0: 
michael@0:   getIntPref: function getIntPref(prefName) {
michael@0:     return this._getOne(prefName, "int");
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Invoke `observer` after a change to the preference `domain` in
michael@0:    * the current branch.
michael@0:    *
michael@0:    * `observer` should implement the nsIObserver.observe interface.
michael@0:    */
michael@0:   addObserver: function addObserver(domain, observer, holdWeak) {
michael@0:     if (!domain)
michael@0:       throw new Error("domain must not be null");
michael@0:     if (!observer)
michael@0:       throw new Error("observer must not be null");
michael@0:     if (holdWeak)
michael@0:       throw new Error("Weak references not yet implemented.");
michael@0: 
michael@0:     if (!this._observers.hasOwnProperty(domain))
michael@0:       this._observers[domain] = [];
michael@0:     if (this._observers[domain].indexOf(observer) > -1)
michael@0:       return;
michael@0: 
michael@0:     this._observers[domain].push(observer);
michael@0: 
michael@0:     this._updateAndroidListener();
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Do not invoke `observer` after a change to the preference
michael@0:    * `domain` in the current branch.
michael@0:    */
michael@0:   removeObserver: function removeObserver(domain, observer) {
michael@0:     if (!this._observers.hasOwnProperty(domain))
michael@0:       return;
michael@0:     let index = this._observers[domain].indexOf(observer);
michael@0:     if (index < 0)
michael@0:       return;
michael@0: 
michael@0:     this._observers[domain].splice(index, 1);
michael@0:     if (this._observers[domain].length < 1)
michael@0:       delete this._observers[domain];
michael@0: 
michael@0:     this._updateAndroidListener();
michael@0:   },
michael@0: 
michael@0:   _updateAndroidListener: function _updateAndroidListener() {
michael@0:     if (this._listening && Object.keys(this._observers).length < 1)
michael@0:       this._uninstallAndroidListener();
michael@0:     if (!this._listening && Object.keys(this._observers).length > 0)
michael@0:       this._installAndroidListener();
michael@0:   },
michael@0: 
michael@0:   _installAndroidListener: function _installAndroidListener() {
michael@0:     if (this._listening)
michael@0:       return;
michael@0:     this._listening = true;
michael@0: 
michael@0:     Services.obs.addObserver(this, "SharedPreferences:Changed", false);
michael@0:     sendMessageToJava({
michael@0:       type: "SharedPreferences:Observe",
michael@0:       enable: true,
michael@0:       branch: this._branch,
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   observe: function observe(subject, topic, data) {
michael@0:     if (topic != "SharedPreferences:Changed") {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     let msg = JSON.parse(data);
michael@0:     if (msg.branch != this._branch) {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     if (!this._observers.hasOwnProperty(msg.key)) {
michael@0:       return;
michael@0:     }
michael@0: 
michael@0:     let observers = this._observers[msg.key];
michael@0:     for (let obs of observers) {
michael@0:       obs.observe(obs, msg.key, msg.value);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _uninstallAndroidListener: function _uninstallAndroidListener() {
michael@0:     if (!this._listening)
michael@0:       return;
michael@0:     this._listening = false;
michael@0: 
michael@0:     Services.obs.removeObserver(this, "SharedPreferences:Changed");
michael@0:     sendMessageToJava({
michael@0:       type: "SharedPreferences:Observe",
michael@0:       enable: false,
michael@0:       branch: this._branch,
michael@0:     });
michael@0:   },
michael@0: });