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.lookup.Lookup.MH; 29 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError; 30 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED; 31 32 import java.lang.invoke.MethodHandle; 33 import java.lang.invoke.MethodHandles; 34 import java.util.ArrayList; 35 import java.util.Arrays; 36 import java.util.BitSet; 37 import jdk.nashorn.internal.runtime.AccessorProperty; 38 import jdk.nashorn.internal.runtime.JSType; 39 import jdk.nashorn.internal.runtime.Property; 40 import jdk.nashorn.internal.runtime.PropertyDescriptor; 41 import jdk.nashorn.internal.runtime.PropertyMap; 42 import jdk.nashorn.internal.runtime.ScriptFunction; 43 import jdk.nashorn.internal.runtime.ScriptObject; 44 import jdk.nashorn.internal.runtime.ScriptRuntime; 45 import jdk.nashorn.internal.runtime.arrays.ArrayData; 46 import jdk.nashorn.internal.runtime.arrays.ArrayIndex; 47 48 /** 49 * ECMA 10.6 Arguments Object. 50 * 51 * Arguments object used for non-strict mode functions. For strict mode, we use 52 * a different implementation (@see NativeStrictArguments). In non-strict mode, 53 * named argument access and index argument access (arguments[i]) are linked. 54 * Modifications reflect on each other access -- till arguments indexed element 55 * is deleted. After delete, there is no link between named access and indexed 56 * access for that deleted index alone. 57 */ 58 public final class NativeArguments extends ScriptObject { 59 60 private static final MethodHandle G$LENGTH = findOwnMH("G$length", Object.class, Object.class); 61 private static final MethodHandle S$LENGTH = findOwnMH("S$length", void.class, Object.class, Object.class); 62 private static final MethodHandle G$CALLEE = findOwnMH("G$callee", Object.class, Object.class); 63 private static final MethodHandle S$CALLEE = findOwnMH("S$callee", void.class, Object.class, Object.class); 64 65 private static final PropertyMap map$; 66 67 static { 68 final ArrayList<Property> properties = new ArrayList<>(2); 69 properties.add(AccessorProperty.create("length", Property.NOT_ENUMERABLE, G$LENGTH, S$LENGTH)); 70 properties.add(AccessorProperty.create("callee", Property.NOT_ENUMERABLE, G$CALLEE, S$CALLEE)); 71 map$ = PropertyMap.newMap(properties); 72 } 73 74 static PropertyMap getInitialMap() { 75 return map$; 76 } 77 78 private Object length; 79 private Object callee; 80 private final int numMapped; 81 private final int numParams; 82 83 // These are lazily initialized when delete is invoked on a mapped arg or an unmapped argument is set. 84 private ArrayData unmappedArgs; 85 private BitSet deleted; 86 87 NativeArguments(final Object[] arguments, final Object callee, final int numParams, final ScriptObject proto, final PropertyMap map) { 88 super(proto, map); 89 setIsArguments(); 90 setArray(ArrayData.allocate(arguments)); 91 this.length = arguments.length; 92 this.callee = callee; 93 this.numMapped = Math.min(numParams, arguments.length); 94 this.numParams = numParams; 95 } 96 97 @Override 98 public String getClassName() { 99 return "Arguments"; 100 } 101 102 /** 103 * getArgument is used for named argument access. 104 */ 105 @Override 106 public Object getArgument(final int key) { 107 assert key >= 0 && key < numParams : "invalid argument index"; 108 return isMapped(key) ? getArray().getObject(key) : getUnmappedArg(key); 109 } 110 111 /** 112 * setArgument is used for named argument set. 113 */ 114 @Override 115 public void setArgument(final int key, final Object value) { 116 assert key >= 0 && key < numParams : "invalid argument index"; 117 if (isMapped(key)) { 118 setArray(getArray().set(key, value, false)); 119 } else { 120 setUnmappedArg(key, value); 121 } 122 } 123 124 @Override 125 public boolean delete(final int key, final boolean strict) { 126 final int index = ArrayIndex.getArrayIndex(key); 127 return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict); 128 } 129 130 @Override 131 public boolean delete(final long key, final boolean strict) { 132 final int index = ArrayIndex.getArrayIndex(key); 133 return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict); 134 } 135 136 @Override 137 public boolean delete(final double key, final boolean strict) { 138 final int index = ArrayIndex.getArrayIndex(key); 139 return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict); 140 } 141 142 @Override 143 public boolean delete(final Object key, final boolean strict) { 144 final Object primitiveKey = JSType.toPrimitive(key, String.class); 145 final int index = ArrayIndex.getArrayIndex(primitiveKey); 146 return isMapped(index) ? deleteMapped(index, strict) : super.delete(primitiveKey, strict); 147 } 148 149 /** 150 * ECMA 15.4.5.1 [[DefineOwnProperty]] ( P, Desc, Throw ) as specialized in 151 * ECMA 10.6 for Arguments object. 152 */ 153 @Override 154 public boolean defineOwnProperty(final String key, final Object propertyDesc, final boolean reject) { 155 final int index = ArrayIndex.getArrayIndex(key); 156 if (index >= 0) { 157 final boolean isMapped = isMapped(index); 158 final Object oldValue = isMapped ? getArray().getObject(index) : null; 159 160 if (!super.defineOwnProperty(key, propertyDesc, false)) { 161 if (reject) { 162 throw typeError("cant.redefine.property", key, ScriptRuntime.safeToString(this)); 163 } 164 return false; 165 } 166 167 if (isMapped) { 168 // When mapped argument is redefined, if new descriptor is accessor property 169 // or data-non-writable property, we have to "unmap" (unlink). 170 final PropertyDescriptor desc = toPropertyDescriptor(Global.instance(), propertyDesc); 171 if (desc.type() == PropertyDescriptor.ACCESSOR) { 172 setDeleted(index, oldValue); 173 } else if (desc.has(PropertyDescriptor.WRITABLE) && !desc.isWritable()) { 174 // delete and set value from new descriptor if it has one, otherwise use old value 175 setDeleted(index, desc.has(PropertyDescriptor.VALUE) ? desc.getValue() : oldValue); 176 } else if (desc.has(PropertyDescriptor.VALUE)) { 177 setArray(getArray().set(index, desc.getValue(), false)); 178 } 179 } 180 181 return true; 182 } 183 184 return super.defineOwnProperty(key, propertyDesc, reject); 185 } 186 187 // Internals below this point 188 189 // We track deletions using a bit set (delete arguments[index]) 190 private boolean isDeleted(final int index) { 191 return deleted != null && deleted.get(index); 192 } 193 194 private void setDeleted(final int index, final Object unmappedValue) { 195 if (deleted == null) { 196 deleted = new BitSet(numMapped); 197 } 198 deleted.set(index, true); 199 setUnmappedArg(index, unmappedValue); 200 } 201 202 private boolean deleteMapped(final int index, final boolean strict) { 203 final Object value = getArray().getObject(index); 204 final boolean success = super.delete(index, strict); 205 if (success) { 206 setDeleted(index, value); 207 } 208 return success; 209 } 210 211 private Object getUnmappedArg(final int key) { 212 assert key >= 0 && key < numParams; 213 return unmappedArgs == null ? UNDEFINED : unmappedArgs.getObject(key); 214 } 215 216 private void setUnmappedArg(final int key, final Object value) { 217 assert key >= 0 && key < numParams; 218 if (unmappedArgs == null) { 219 /* 220 * Declared number of parameters may be more or less than the actual passed 221 * runtime arguments count. We need to truncate or extend with undefined values. 222 * 223 * Example: 224 * 225 * // less declared params 226 * (function (x) { print(arguments); })(20, 44); 227 * 228 * // more declared params 229 * (function (x, y) { print(arguments); })(3); 230 */ 231 final Object[] newValues = new Object[numParams]; 232 System.arraycopy(getArray().asObjectArray(), 0, newValues, 0, numMapped); 233 if (numMapped < numParams) { 234 Arrays.fill(newValues, numMapped, numParams, UNDEFINED); 235 } 236 this.unmappedArgs = ArrayData.allocate(newValues); 237 } 238 // Set value of argument 239 unmappedArgs = unmappedArgs.set(key, value, false); 240 } 241 242 /** 243 * Are arguments[index] and corresponding named parameter linked? 244 * 245 * In non-strict mode, arguments[index] and corresponding named param are "linked" or "mapped" 246 * if the argument is provided by the caller. Modifications are tacked b/w each other - until 247 * (delete arguments[index]) is used. Once deleted, the corresponding arg is no longer 'mapped'. 248 * Please note that delete can happen only through the arguments array - named param can not 249 * be deleted. (delete is one-way). 250 */ 251 private boolean isMapped(final int index) { 252 // in mapped named args and not marked as "deleted" 253 return index >= 0 && index < numMapped && !isDeleted(index); 254 } 255 256 /** 257 * Factory to create correct Arguments object based on strict mode. 258 * 259 * @param arguments the actual arguments array passed 260 * @param callee the callee function that uses arguments object 261 * @param numParams the number of declared (named) function parameters 262 * @return Arguments Object 263 */ 264 public static ScriptObject allocate(final Object[] arguments, final ScriptFunction callee, final int numParams) { 265 // Strict functions won't always have a callee for arguments, and will pass null instead. 266 final boolean isStrict = callee == null || callee.isStrict(); 267 final Global global = Global.instance(); 268 final ScriptObject proto = global.getObjectPrototype(); 269 if (isStrict) { 270 return new NativeStrictArguments(arguments, numParams, proto, NativeStrictArguments.getInitialMap()); 271 } 272 return new NativeArguments(arguments, callee, numParams, proto, NativeArguments.getInitialMap()); 273 } 274 275 /** 276 * Length getter 277 * @param self self reference 278 * @return length property value 279 */ 280 public static Object G$length(final Object self) { 281 if (self instanceof NativeArguments) { 282 return ((NativeArguments)self).getArgumentsLength(); 283 } 284 285 return 0; 286 } 287 288 /** 289 * Length setter 290 * @param self self reference 291 * @param value value for length property 292 */ 293 public static void S$length(final Object self, final Object value) { 294 if (self instanceof NativeArguments) { 295 ((NativeArguments)self).setArgumentsLength(value); 296 } 297 } 298 299 /** 300 * Callee getter 301 * @param self self reference 302 * @return value for callee property 303 */ 304 public static Object G$callee(final Object self) { 305 if (self instanceof NativeArguments) { 306 return ((NativeArguments)self).getCallee(); 307 } 308 return UNDEFINED; 309 } 310 311 /** 312 * Callee setter 313 * @param self self reference 314 * @param value value for callee property 315 */ 316 public static void S$callee(final Object self, final Object value) { 317 if (self instanceof NativeArguments) { 318 ((NativeArguments)self).setCallee(value); 319 } 320 } 321 322 @Override 323 public Object getLength() { 324 return length; 325 } 326 327 private Object getArgumentsLength() { 328 return length; 329 } 330 331 private void setArgumentsLength(final Object length) { 332 this.length = length; 333 } 334 335 private Object getCallee() { 336 return callee; 337 } 338 339 private void setCallee(final Object callee) { 340 this.callee = callee; 341 } 342 343 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 344 return MH.findStatic(MethodHandles.lookup(), NativeArguments.class, name, MH.type(rtype, types)); 345 } 346 }