| // Copyright 2009 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS-IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /** |
| * @fileoverview Useful compiler idioms. |
| * |
| * @author johnlenz@google.com (John Lenz) |
| */ |
| |
| goog.provide('goog.reflect'); |
| |
| |
| /** |
| * Syntax for object literal casts. |
| * @see http://go/jscompiler-renaming |
| * @see http://code.google.com/p/closure-compiler/wiki/ |
| * ExperimentalTypeBasedPropertyRenaming |
| * |
| * Use this if you have an object literal whose keys need to have the same names |
| * as the properties of some class even after they are renamed by the compiler. |
| * |
| * @param {!Function} type Type to cast to. |
| * @param {Object} object Object literal to cast. |
| * @return {Object} The object literal. |
| */ |
| goog.reflect.object = function(type, object) { |
| return object; |
| }; |
| |
| |
| /** |
| * To assert to the compiler that an operation is needed when it would |
| * otherwise be stripped. For example: |
| * <code> |
| * // Force a layout |
| * goog.reflect.sinkValue(dialog.offsetHeight); |
| * </code> |
| * @type {!Function} |
| */ |
| goog.reflect.sinkValue = function(x) { |
| goog.reflect.sinkValue[' '](x); |
| return x; |
| }; |
| |
| |
| /** |
| * The compiler should optimize this function away iff no one ever uses |
| * goog.reflect.sinkValue. |
| */ |
| goog.reflect.sinkValue[' '] = goog.nullFunction; |
| |
| |
| /** |
| * Check if a property can be accessed without throwing an exception. |
| * @param {Object} obj The owner of the property. |
| * @param {string} prop The property name. |
| * @return {boolean} Whether the property is accessible. Will also return true |
| * if obj is null. |
| */ |
| goog.reflect.canAccessProperty = function(obj, prop) { |
| /** @preserveTry */ |
| try { |
| goog.reflect.sinkValue(obj[prop]); |
| return true; |
| } catch (e) {} |
| return false; |
| }; |