1 /* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.nashorn.internal.objects; 27 28 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED; 29 import static jdk.nashorn.internal.lookup.Lookup.MH; 30 31 import java.lang.invoke.MethodHandle; 32 import java.lang.invoke.MethodHandles; 33 import java.util.ArrayList; 34 import jdk.nashorn.internal.runtime.AccessorProperty; 35 import jdk.nashorn.internal.runtime.Property; 36 import jdk.nashorn.internal.runtime.PropertyMap; 37 import jdk.nashorn.internal.runtime.ScriptFunction; 38 import jdk.nashorn.internal.runtime.ScriptObject; 39 40 /** 41 * Instances of this class serve as "prototype" object for script functions. 42 * The purpose is to expose "constructor" property from "prototype". Also, nasgen 43 * generated prototype classes extend from this class. 44 * 45 */ 46 public class PrototypeObject extends ScriptObject { 47 private static final PropertyMap map$; 48 49 private Object constructor; 50 51 private static final MethodHandle GET_CONSTRUCTOR = findOwnMH("getConstructor", Object.class, Object.class); 52 private static final MethodHandle SET_CONSTRUCTOR = findOwnMH("setConstructor", void.class, Object.class, Object.class); 53 54 static { 55 final ArrayList<Property> properties = new ArrayList<>(1); 56 properties.add(AccessorProperty.create("constructor", Property.NOT_ENUMERABLE, GET_CONSTRUCTOR, SET_CONSTRUCTOR)); 57 map$ = PropertyMap.newMap(properties); 58 } 59 60 private PrototypeObject(final Global global, final PropertyMap map) { 61 super(global.getObjectPrototype(), map != map$? map.addAll(map$) : map$); 62 } 63 64 PrototypeObject() { 65 this(Global.instance(), map$); 66 } 67 68 /** 69 * PropertyObject constructor 70 * 71 * @param map property map 72 */ 73 PrototypeObject(final PropertyMap map) { 74 this(Global.instance(), map); 75 } 76 77 PrototypeObject(final ScriptFunction func) { 78 this(Global.instance(), map$); 79 this.constructor = func; 80 } 81 82 /** 83 * Get the constructor for this {@code PrototypeObject} 84 * @param self self reference 85 * @return constructor, probably, but not necessarily, a {@link ScriptFunction} 86 */ 87 static Object getConstructor(final Object self) { 88 return (self instanceof PrototypeObject) ? 89 ((PrototypeObject)self).getConstructor() : 90 UNDEFINED; 91 } 92 93 /** 94 * Reset the constructor for this {@code PrototypeObject} 95 * @param self self reference 96 * @param constructor constructor, probably, but not necessarily, a {@link ScriptFunction} 97 */ 98 static void setConstructor(final Object self, final Object constructor) { 99 if (self instanceof PrototypeObject) { 100 ((PrototypeObject)self).setConstructor(constructor); 101 } 102 } 103 104 private Object getConstructor() { 105 return constructor; 106 } 107 108 private void setConstructor(final Object constructor) { 109 this.constructor = constructor; 110 } 111 112 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 113 return MH.findStatic(MethodHandles.lookup(), PrototypeObject.class, name, MH.type(rtype, types)); 114 } 115 }