15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2010 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/** 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @fileoverview This contains an implementation of the EventTarget interface 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * as defined by DOM Level 2 Events. 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)cr.define('cr', function() { 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) /** 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Creates a new EventTarget. This class implements the DOM level 2 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * EventTarget interface and can be used wherever those are used. 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @constructor 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) function EventTarget() { 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) EventTarget.prototype = { 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) /** 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Adds an event listener to the target. 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @param {string} type The name of the event. 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @param {!Function|{handleEvent:Function}} handler The handler for the 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * event. This is called when the event is dispatched. 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) addEventListener: function(type, handler) { 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!this.listeners_) 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) this.listeners_ = Object.create(null); 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!(type in this.listeners_)) { 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) this.listeners_[type] = [handler]; 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } else { 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var handlers = this.listeners_[type]; 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (handlers.indexOf(handler) < 0) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) handlers.push(handler); 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }, 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) /** 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Removes an event listener from the target. 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @param {string} type The name of the event. 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @param {!Function|{handleEvent:Function}} handler The handler for the 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * event. 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) removeEventListener: function(type, handler) { 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!this.listeners_) 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return; 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (type in this.listeners_) { 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var handlers = this.listeners_[type]; 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var index = handlers.indexOf(handler); 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (index >= 0) { 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Clean up if this was the last listener. 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (handlers.length == 1) 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) delete this.listeners_[type]; 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) else 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) handlers.splice(index, 1); 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }, 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) /** 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Dispatches an event and calls all the listeners that are listening to 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * the type of the event. 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @param {!cr.event.Event} event The event to dispatch. 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * @return {boolean} Whether the default action was prevented. If someone 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * calls preventDefault on the event object then this returns false. 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) dispatchEvent: function(event) { 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!this.listeners_) 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return true; 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Since we are using DOM Event objects we need to override some of the 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // properties and methods so that we can emulate this correctly. 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var self = this; 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) event.__defineGetter__('target', function() { 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return self; 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }); 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var type = event.type; 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var prevented = 0; 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (type in this.listeners_) { 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Clone to prevent removal during dispatch 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) var handlers = this.listeners_[type].concat(); 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) for (var i = 0, handler; handler = handlers[i]; i++) { 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (handler.handleEvent) 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) prevented |= handler.handleEvent.call(handler, event) === false; 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) else 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) prevented |= handler.call(this, event) === false; 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 93424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) return !prevented && !event.defaultPrevented; 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Export 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return { 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) EventTarget: EventTarget 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}); 102