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 double 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 Object key, final boolean strict) {
138 final Object primitiveKey = JSType.toPrimitive(key, String.class);
139 final int index = ArrayIndex.getArrayIndex(primitiveKey);
140 return isMapped(index) ? deleteMapped(index, strict) : super.delete(primitiveKey, strict);
141 }
142
143 /**
144 * ECMA 15.4.5.1 [[DefineOwnProperty]] ( P, Desc, Throw ) as specialized in
145 * ECMA 10.6 for Arguments object.
146 */
147 @Override
148 public boolean defineOwnProperty(final String key, final Object propertyDesc, final boolean reject) {
149 final int index = ArrayIndex.getArrayIndex(key);
150 if (index >= 0) {
151 final boolean isMapped = isMapped(index);
152 final Object oldValue = isMapped ? getArray().getObject(index) : null;
153
154 if (!super.defineOwnProperty(key, propertyDesc, false)) {
155 if (reject) {
156 throw typeError("cant.redefine.property", key, ScriptRuntime.safeToString(this));
157 }
158 return false;
159 }
160
161 if (isMapped) {
162 // When mapped argument is redefined, if new descriptor is accessor property
163 // or data-non-writable property, we have to "unmap" (unlink).
164 final PropertyDescriptor desc = toPropertyDescriptor(Global.instance(), propertyDesc);
165 if (desc.type() == PropertyDescriptor.ACCESSOR) {
166 setDeleted(index, oldValue);
167 } else if (desc.has(PropertyDescriptor.WRITABLE) && !desc.isWritable()) {
168 // delete and set value from new descriptor if it has one, otherwise use old value
169 setDeleted(index, desc.has(PropertyDescriptor.VALUE) ? desc.getValue() : oldValue);
170 } else if (desc.has(PropertyDescriptor.VALUE)) {
171 setArray(getArray().set(index, desc.getValue(), false));
172 }
173 }
174
175 return true;
176 }
177
178 return super.defineOwnProperty(key, propertyDesc, reject);
179 }
180
181 // Internals below this point
182
183 // We track deletions using a bit set (delete arguments[index])
184 private boolean isDeleted(final int index) {
185 return deleted != null && deleted.get(index);
186 }
187
188 private void setDeleted(final int index, final Object unmappedValue) {
189 if (deleted == null) {
190 deleted = new BitSet(numMapped);
191 }
192 deleted.set(index, true);
193 setUnmappedArg(index, unmappedValue);
194 }
195
196 private boolean deleteMapped(final int index, final boolean strict) {
197 final Object value = getArray().getObject(index);
198 final boolean success = super.delete(index, strict);
199 if (success) {
200 setDeleted(index, value);
201 }
202 return success;
203 }
204
205 private Object getUnmappedArg(final int key) {
206 assert key >= 0 && key < numParams;
207 return unmappedArgs == null ? UNDEFINED : unmappedArgs.getObject(key);
208 }
209
210 private void setUnmappedArg(final int key, final Object value) {
211 assert key >= 0 && key < numParams;
212 if (unmappedArgs == null) {
213 /*
214 * Declared number of parameters may be more or less than the actual passed
215 * runtime arguments count. We need to truncate or extend with undefined values.
216 *
217 * Example:
218 *
219 * // less declared params
220 * (function (x) { print(arguments); })(20, 44);
221 *
222 * // more declared params
223 * (function (x, y) { print(arguments); })(3);
224 */
225 final Object[] newValues = new Object[numParams];
226 System.arraycopy(getArray().asObjectArray(), 0, newValues, 0, numMapped);
227 if (numMapped < numParams) {
228 Arrays.fill(newValues, numMapped, numParams, UNDEFINED);
229 }
230 this.unmappedArgs = ArrayData.allocate(newValues);
231 }
232 // Set value of argument
233 unmappedArgs = unmappedArgs.set(key, value, false);
234 }
235
236 /**
237 * Are arguments[index] and corresponding named parameter linked?
238 *
239 * In non-strict mode, arguments[index] and corresponding named param are "linked" or "mapped"
240 * if the argument is provided by the caller. Modifications are tacked b/w each other - until
241 * (delete arguments[index]) is used. Once deleted, the corresponding arg is no longer 'mapped'.
242 * Please note that delete can happen only through the arguments array - named param can not
243 * be deleted. (delete is one-way).
244 */
245 private boolean isMapped(final int index) {
246 // in mapped named args and not marked as "deleted"
247 return index >= 0 && index < numMapped && !isDeleted(index);
248 }
249
250 /**
251 * Factory to create correct Arguments object based on strict mode.
252 *
253 * @param arguments the actual arguments array passed
254 * @param callee the callee function that uses arguments object
255 * @param numParams the number of declared (named) function parameters
256 * @return Arguments Object
257 */
258 public static ScriptObject allocate(final Object[] arguments, final ScriptFunction callee, final int numParams) {
259 // Strict functions won't always have a callee for arguments, and will pass null instead.
260 final boolean isStrict = callee == null || callee.isStrict();
261 final Global global = Global.instance();
262 final ScriptObject proto = global.getObjectPrototype();
263 if (isStrict) {
264 return new NativeStrictArguments(arguments, numParams, proto, NativeStrictArguments.getInitialMap());
265 }
266 return new NativeArguments(arguments, callee, numParams, proto, NativeArguments.getInitialMap());
267 }
268
269 /**
270 * Length getter
271 * @param self self reference
272 * @return length property value
273 */
274 public static Object G$length(final Object self) {
275 if (self instanceof NativeArguments) {
276 return ((NativeArguments)self).getArgumentsLength();
277 }
278
279 return 0;
280 }
281
282 /**
283 * Length setter
284 * @param self self reference
285 * @param value value for length property
286 */
287 public static void S$length(final Object self, final Object value) {
288 if (self instanceof NativeArguments) {
289 ((NativeArguments)self).setArgumentsLength(value);
290 }
291 }
292
293 /**
294 * Callee getter
295 * @param self self reference
296 * @return value for callee property
297 */
298 public static Object G$callee(final Object self) {
299 if (self instanceof NativeArguments) {
300 return ((NativeArguments)self).getCallee();
301 }
302 return UNDEFINED;
303 }
304
305 /**
306 * Callee setter
307 * @param self self reference
308 * @param value value for callee property
309 */
310 public static void S$callee(final Object self, final Object value) {
311 if (self instanceof NativeArguments) {
312 ((NativeArguments)self).setCallee(value);
313 }
314 }
315
316 @Override
317 public Object getLength() {
318 return length;
319 }
320
321 private Object getArgumentsLength() {
322 return length;
323 }
324
325 private void setArgumentsLength(final Object length) {
326 this.length = length;
327 }
328
329 private Object getCallee() {
330 return callee;
331 }
332
333 private void setCallee(final Object callee) {
334 this.callee = callee;
335 }
336
337 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
338 return MH.findStatic(MethodHandles.lookup(), NativeArguments.class, name, MH.type(rtype, types));
339 }
340 }