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 26package jdk.nashorn.internal.codegen; 27 28import java.util.ArrayList; 29import java.util.Arrays; 30import java.util.HashMap; 31import java.util.List; 32import java.util.Map; 33import java.util.Objects; 34 35import jdk.nashorn.internal.runtime.PropertyMap; 36 37/** 38 * Manages constants needed by code generation. Objects are maintained in an 39 * interning maps to remove duplicates. 40 */ 41final class ConstantData { 42 /** Constant table. */ 43 final List<Object> constants; 44 45 /** Constant table string interning map. */ 46 final Map<String, Integer> stringMap; 47 48 /** Constant table object interning map. */ 49 final Map<Object, Integer> objectMap; 50 51 private static class ArrayWrapper { 52 private final Object array; 53 private final int hashCode; 54 55 public ArrayWrapper(final Object array) { 56 this.array = array; 57 this.hashCode = calcHashCode(); 58 } 59 60 /** 61 * Calculate a shallow hashcode for the array. 62 * @return Hashcode with elements factored in. 63 */ 64 private int calcHashCode() { 65 final Class<?> cls = array.getClass(); 66 67 if (!cls.getComponentType().isPrimitive()) { 68 return Arrays.hashCode((Object[])array); 69 } else if (cls == double[].class) { 70 return Arrays.hashCode((double[])array); 71 } if (cls == long[].class) { 72 return Arrays.hashCode((long[])array); 73 } if (cls == int[].class) { 74 return Arrays.hashCode((int[])array); 75 } 76 77 throw new AssertionError("ConstantData doesn't support " + cls); 78 } 79 80 @Override 81 public boolean equals(final Object other) { 82 if (!(other instanceof ArrayWrapper)) { 83 return false; 84 } 85 86 final Object otherArray = ((ArrayWrapper)other).array; 87 88 if (array == otherArray) { 89 return true; 90 } 91 92 final Class<?> cls = array.getClass(); 93 94 if (cls == otherArray.getClass()) { 95 if (!cls.getComponentType().isPrimitive()) { 96 return Arrays.equals((Object[])array, (Object[])otherArray); 97 } else if (cls == double[].class) { 98 return Arrays.equals((double[])array, (double[])otherArray); 99 } else if (cls == long[].class) { 100 return Arrays.equals((long[])array, (long[])otherArray); 101 } else if (cls == int[].class) { 102 return Arrays.equals((int[])array, (int[])otherArray); 103 } 104 } 105 106 return false; 107 } 108 109 @Override 110 public int hashCode() { 111 return hashCode; 112 } 113 } 114 115 /** 116 * {@link PropertyMap} wrapper class that provides implementations for the {@code hashCode} and {@code equals} 117 * methods that are based on the map layout. {@code PropertyMap} itself inherits the identity based implementations 118 * from {@code java.lang.Object}. 119 */ 120 private static class PropertyMapWrapper { 121 private final PropertyMap propertyMap; 122 private final int hashCode; 123 124 public PropertyMapWrapper(final PropertyMap map) { 125 this.hashCode = Arrays.hashCode(map.getProperties()) + 31 * Objects.hashCode(map.getClassName()); 126 this.propertyMap = map; 127 } 128 129 @Override 130 public int hashCode() { 131 return hashCode; 132 } 133 134 @Override 135 public boolean equals(final Object other) { 136 if (!(other instanceof PropertyMapWrapper)) { 137 return false; 138 } 139 final PropertyMap otherMap = ((PropertyMapWrapper) other).propertyMap; 140 return propertyMap == otherMap 141 || (Arrays.equals(propertyMap.getProperties(), otherMap.getProperties()) 142 && Objects.equals(propertyMap.getClassName(), otherMap.getClassName())); 143 } 144 } 145 146 /** 147 * Constructor 148 */ 149 ConstantData() { 150 this.constants = new ArrayList<>(); 151 this.stringMap = new HashMap<>(); 152 this.objectMap = new HashMap<>(); 153 } 154 155 /** 156 * Add a string to the constant data 157 * 158 * @param string the string to add 159 * @return the index in the constant pool that the string was given 160 */ 161 public int add(final String string) { 162 final Integer value = stringMap.get(string); 163 164 if (value != null) { 165 return value; 166 } 167 168 constants.add(string); 169 final int index = constants.size() - 1; 170 stringMap.put(string, index); 171 172 return index; 173 } 174 175 /** 176 * Add an object to the constant data 177 * 178 * @param object the string to add 179 * @return the index in the constant pool that the object was given 180 */ 181 public int add(final Object object) { 182 assert object != null; 183 final Object entry; 184 if (object.getClass().isArray()) { 185 entry = new ArrayWrapper(object); 186 } else if (object instanceof PropertyMap) { 187 entry = new PropertyMapWrapper((PropertyMap) object); 188 } else { 189 entry = object; 190 } 191 final Integer value = objectMap.get(entry); 192 193 if (value != null) { 194 return value; 195 } 196 197 constants.add(object); 198 final int index = constants.size() - 1; 199 objectMap.put(entry, index); 200 201 return index; 202 } 203 204 Object[] toArray() { 205 return constants.toArray(); 206 } 207} 208