NativeSymbol.java revision 1594:9ab6b645c428
1/* 2 * Copyright (c) 2015, 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.objects; 27 28import static jdk.nashorn.internal.lookup.Lookup.MH; 29import static jdk.nashorn.internal.runtime.ECMAErrors.typeError; 30 31import java.lang.invoke.MethodHandle; 32import java.lang.invoke.MethodHandles; 33import java.lang.invoke.MethodType; 34import jdk.dynalink.linker.GuardedInvocation; 35import jdk.dynalink.linker.LinkRequest; 36import jdk.nashorn.internal.WeakValueCache; 37import jdk.nashorn.internal.objects.annotations.Attribute; 38import jdk.nashorn.internal.objects.annotations.Constructor; 39import jdk.nashorn.internal.objects.annotations.Function; 40import jdk.nashorn.internal.objects.annotations.ScriptClass; 41import jdk.nashorn.internal.objects.annotations.Where; 42import jdk.nashorn.internal.runtime.JSType; 43import jdk.nashorn.internal.runtime.PropertyMap; 44import jdk.nashorn.internal.runtime.ScriptObject; 45import jdk.nashorn.internal.runtime.ScriptRuntime; 46import jdk.nashorn.internal.runtime.Symbol; 47import jdk.nashorn.internal.runtime.Undefined; 48import jdk.nashorn.internal.runtime.linker.PrimitiveLookup; 49 50/** 51 * ECMAScript 6 - 19.4 Symbol Objects 52 */ 53@ScriptClass("Symbol") 54public final class NativeSymbol extends ScriptObject { 55 56 private final Symbol symbol; 57 58 /** Method handle to create an object wrapper for a primitive symbol. */ 59 static final MethodHandle WRAPFILTER = findOwnMH("wrapFilter", MH.type(NativeSymbol.class, Object.class)); 60 /** Method handle to retrieve the Symbol prototype object. */ 61 private static final MethodHandle PROTOFILTER = findOwnMH("protoFilter", MH.type(Object.class, Object.class)); 62 63 // initialized by nasgen 64 private static PropertyMap $nasgenmap$; 65 66 /** See ES6 19.4.2.1 */ 67 private static WeakValueCache<String, Symbol> globalSymbolRegistry = new WeakValueCache<>(); 68 69 NativeSymbol(final Symbol symbol) { 70 this(symbol, Global.instance()); 71 } 72 73 NativeSymbol(final Symbol symbol, final Global global) { 74 this(symbol, global.getSymbolPrototype(), $nasgenmap$); 75 } 76 77 private NativeSymbol(final Symbol symbol, final ScriptObject prototype, final PropertyMap map) { 78 super(prototype, map); 79 this.symbol = symbol; 80 } 81 82 private static Symbol getSymbolValue(final Object self) { 83 if (self instanceof Symbol) { 84 return (Symbol) self; 85 } else if (self instanceof NativeSymbol) { 86 return ((NativeSymbol) self).symbol; 87 } else { 88 throw typeError("not.a.symbol"); 89 } 90 } 91 92 /** 93 * Lookup the appropriate method for an invoke dynamic call. 94 * 95 * @param request The link request 96 * @param receiver The receiver for the call 97 * @return Link to be invoked at call site. 98 */ 99 public static GuardedInvocation lookupPrimitive(final LinkRequest request, final Object receiver) { 100 return PrimitiveLookup.lookupPrimitive(request, Symbol.class, new NativeSymbol((Symbol)receiver), WRAPFILTER, PROTOFILTER); 101 } 102 103 // ECMA 6 19.4.3.4 Symbol.prototype [ @@toPrimitive ] ( hint ) 104 @Override 105 public Object getDefaultValue(final Class<?> typeHint) { 106 // Just return the symbol value. 107 return symbol; 108 } 109 110 /** 111 * ECMA 6 19.4.3.2 Symbol.prototype.toString ( ) 112 * 113 * @param self self reference 114 * @return localized string for this Number 115 */ 116 @Function(attributes = Attribute.NOT_ENUMERABLE) 117 public static String toString(final Object self) { 118 return getSymbolValue(self).toString(); 119 } 120 121 122 /** 123 * ECMA 6 19.4.3.3 Symbol.prototype.valueOf ( ) 124 * 125 * @param self self reference 126 * @return number value for this Number 127 */ 128 @Function(attributes = Attribute.NOT_ENUMERABLE) 129 public static Object valueOf(final Object self) { 130 return getSymbolValue(self); 131 } 132 133 /** 134 * ECMA 6 19.4.1.1 Symbol ( [ description ] ) 135 * 136 * @param newObj is this function invoked with the new operator 137 * @param self self reference 138 * @param args arguments 139 * @return new symbol value 140 */ 141 @Constructor(arity = 1) 142 public static Object constructor(final boolean newObj, final Object self, final Object... args) { 143 if (newObj) { 144 throw typeError("symbol.as.constructor"); 145 } 146 final String description = args.length > 0 && args[0] != Undefined.getUndefined() ? 147 JSType.toString(args[0]) : ""; 148 return new Symbol(description); 149 } 150 151 /** 152 * ES6 19.4.2.1 Symbol.for ( key ) 153 * 154 * @param self self reference 155 * @param arg the argument 156 * @return the symbol value 157 */ 158 @Function(name = "for", attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) 159 public synchronized static Object _for(final Object self, final Object arg) { 160 final String name = JSType.toString(arg); 161 return globalSymbolRegistry.getOrCreate(name, Symbol::new); 162 } 163 164 /** 165 * ES6 19.4.2.5 Symbol.keyFor ( sym ) 166 * 167 * @param self self reference 168 * @param arg the argument 169 * @return the symbol name 170 */ 171 @Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR) 172 public synchronized static Object keyFor(final Object self, final Object arg) { 173 if (!(arg instanceof Symbol)) { 174 throw typeError("not.a.symbol", ScriptRuntime.safeToString(arg)); 175 } 176 final String name = ((Symbol) arg).getName(); 177 return globalSymbolRegistry.get(name) == arg ? name : Undefined.getUndefined(); 178 } 179 180 @SuppressWarnings("unused") 181 private static NativeSymbol wrapFilter(final Object receiver) { 182 return new NativeSymbol((Symbol)receiver); 183 } 184 185 @SuppressWarnings("unused") 186 private static Object protoFilter(final Object object) { 187 return Global.instance().getSymbolPrototype(); 188 } 189 190 private static MethodHandle findOwnMH(final String name, final MethodType type) { 191 return MH.findStatic(MethodHandles.lookup(), NativeSymbol.class, name, type); 192 } 193 194} 195