| // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| /** @fileoverview EventTracker is a simple class that manages the addition and |
| * removal of DOM event listeners. In particular, it keeps track of all |
| * listeners that have been added and makes it easy to remove some or all of |
| * them without requiring all the information again. This is particularly |
| * handy when the listener is a generated function such as a lambda or the |
| * result of calling Function.bind. |
| */ |
| |
| // Use an anonymous function to enable strict mode just for this file (which |
| // will be concatenated with other files when embedded in Chrome) |
| var EventTracker = (function() { |
| 'use strict'; |
| |
| /** |
| * Create an EventTracker to track a set of events. |
| * EventTracker instances are typically tied 1:1 with other objects or |
| * DOM elements whose listeners should be removed when the object is disposed |
| * or the corresponding elements are removed from the DOM. |
| * @constructor |
| */ |
| function EventTracker() { |
| /** |
| * @type {Array.<EventTracker.Entry>} |
| * @private |
| */ |
| this.listeners_ = []; |
| } |
| |
| /** |
| * The type of the internal tracking entry. |
| * @typedef {{node: !Node, |
| * eventType: string, |
| * listener: Function, |
| * capture: boolean}} |
| */ |
| EventTracker.Entry; |
| |
| EventTracker.prototype = { |
| /** |
| * Add an event listener - replacement for Node.addEventListener. |
| * @param {!Node} node The DOM node to add a listener to. |
| * @param {string} eventType The type of event to subscribe to. |
| * @param {Function} listener The listener to add. |
| * @param {boolean} capture Whether to invoke during the capture phase. |
| */ |
| add: function(node, eventType, listener, capture) { |
| var h = { |
| node: node, |
| eventType: eventType, |
| listener: listener, |
| capture: capture |
| }; |
| this.listeners_.push(h); |
| node.addEventListener(eventType, listener, capture); |
| }, |
| |
| /** |
| * Remove any specified event listeners added with this EventTracker. |
| * @param {!Node} node The DOM node to remove a listener from. |
| * @param {?string} eventType The type of event to remove. |
| */ |
| remove: function(node, eventType) { |
| this.listeners_ = this.listeners_.filter(function(h) { |
| if (h.node == node && (!eventType || (h.eventType == eventType))) { |
| EventTracker.removeEventListener_(h); |
| return false; |
| } |
| return true; |
| }); |
| }, |
| |
| /** |
| * Remove all event listeners added with this EventTracker. |
| */ |
| removeAll: function() { |
| this.listeners_.forEach(EventTracker.removeEventListener_); |
| this.listeners_ = []; |
| } |
| }; |
| |
| /** |
| * Remove a single event listener given it's tracker entry. It's up to the |
| * caller to ensure the entry is removed from listeners_. |
| * @param {EventTracker.Entry} h The entry describing the listener to remove. |
| * @private |
| */ |
| EventTracker.removeEventListener_ = function(h) { |
| h.node.removeEventListener(h.eventType, h.listener, h.capture); |
| }; |
| |
| return EventTracker; |
| })(); |
| |