| /* |
| * Copyright (C) 2014, 2015 Apple Inc. All rights reserved. |
| * Copyright (C) 2013, 2014 University of Washington. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| WI.EventListener = class EventListener |
| { |
| constructor(thisObject, fireOnce) |
| { |
| this._thisObject = thisObject; |
| this._emitter = null; |
| this._callback = null; |
| this._fireOnce = fireOnce; |
| } |
| |
| // Public |
| |
| connect(emitter, type, callback, usesCapture) |
| { |
| console.assert(!this._emitter && !this._callback, "EventListener already bound to a callback.", this); |
| console.assert(emitter, `Missing event emitter for event: ${type}.`); |
| console.assert(type, "Missing event type."); |
| console.assert(callback, `Missing callback for event: ${type}.`); |
| var emitterIsValid = emitter && (emitter instanceof WI.Object || emitter instanceof Node || (typeof emitter.addEventListener === "function")); |
| console.assert(emitterIsValid, "Event emitter ", emitter, ` (type: ${type}) is null or does not implement Node or WI.Object.`); |
| |
| if (!emitterIsValid || !type || !callback) |
| return; |
| |
| this._emitter = emitter; |
| this._type = type; |
| this._usesCapture = !!usesCapture; |
| |
| if (emitter instanceof Node) |
| callback = callback.bind(this._thisObject); |
| |
| if (this._fireOnce) { |
| var listener = this; |
| this._callback = function() { |
| listener.disconnect(); |
| callback.apply(this, arguments); |
| }; |
| } else |
| this._callback = callback; |
| |
| if (this._emitter instanceof Node) |
| this._emitter.addEventListener(this._type, this._callback, this._usesCapture); |
| else |
| this._emitter.addEventListener(this._type, this._callback, this._thisObject); |
| } |
| |
| disconnect() |
| { |
| console.assert(this._emitter && this._callback, "EventListener is not bound to a callback.", this); |
| |
| if (!this._emitter || !this._callback) |
| return; |
| |
| if (this._emitter instanceof Node) |
| this._emitter.removeEventListener(this._type, this._callback, this._usesCapture); |
| else |
| this._emitter.removeEventListener(this._type, this._callback, this._thisObject); |
| |
| if (this._fireOnce) |
| delete this._thisObject; |
| delete this._emitter; |
| delete this._type; |
| delete this._callback; |
| } |
| }; |