runtime/ObjectConstructor.cpp

   1 /*
   2  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
   3  *  Copyright (C) 2008 Apple Inc. All rights reserved.
   4  *
   5  *  This library is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU Lesser General Public
   7  *  License as published by the Free Software Foundation; either
   8  *  version 2 of the License, or (at your option) any later version.
   9  *
  10  *  This library is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *  Lesser General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU Lesser General Public
  16  *  License along with this library; if not, write to the Free Software
  17  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  18  *
  19  */
  20
  21 #include "config.h"
  22 #include "ObjectConstructor.h"
  23
  24 #include "ButterflyInlines.h"
  25 #include "CopiedSpaceInlines.h"
  26 #include "Error.h"
  27 #include "ExceptionHelpers.h"
  28 #include "JSFunction.h"
  29 #include "JSArray.h"
  30 #include "JSGlobalObject.h"
  31 #include "Lookup.h"
  32 #include "ObjectPrototype.h"
  33 #include "JSCInlines.h"
  34 #include "PropertyDescriptor.h"
  35 #include "PropertyNameArray.h"
  36 #include "StackVisitor.h"
  37
  38 namespace JSC {
  39
  40 static EncodedJSValue JSC_HOST_CALL objectConstructorGetPrototypeOf(ExecState*);
  41 static EncodedJSValue JSC_HOST_CALL objectConstructorGetOwnPropertyDescriptor(ExecState*);
  42 static EncodedJSValue JSC_HOST_CALL objectConstructorGetOwnPropertyNames(ExecState*);
  43 static EncodedJSValue JSC_HOST_CALL objectConstructorKeys(ExecState*);
  44 static EncodedJSValue JSC_HOST_CALL objectConstructorDefineProperty(ExecState*);
  45 static EncodedJSValue JSC_HOST_CALL objectConstructorDefineProperties(ExecState*);
  46 static EncodedJSValue JSC_HOST_CALL objectConstructorCreate(ExecState*);
  47 static EncodedJSValue JSC_HOST_CALL objectConstructorSeal(ExecState*);
  48 static EncodedJSValue JSC_HOST_CALL objectConstructorFreeze(ExecState*);
  49 static EncodedJSValue JSC_HOST_CALL objectConstructorPreventExtensions(ExecState*);
  50 static EncodedJSValue JSC_HOST_CALL objectConstructorIsSealed(ExecState*);
  51 static EncodedJSValue JSC_HOST_CALL objectConstructorIsFrozen(ExecState*);
  52 static EncodedJSValue JSC_HOST_CALL objectConstructorIsExtensible(ExecState*);
  53
  54 }
  55
  56 #include "ObjectConstructor.lut.h"
  57
  58 namespace JSC {
  59
  60 STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(ObjectConstructor);
  61
  62 const ClassInfo ObjectConstructor::s_info = { "Function", &InternalFunction::s_info, 0, ExecState::objectConstructorTable, CREATE_METHOD_TABLE(ObjectConstructor) };
  63
  64 /* Source for ObjectConstructor.lut.h
  65 @begin objectConstructorTable
  66   getPrototypeOf            objectConstructorGetPrototypeOf             DontEnum|Function 1
  67   getOwnPropertyDescriptor  objectConstructorGetOwnPropertyDescriptor   DontEnum|Function 2
  68   getOwnPropertyNames       objectConstructorGetOwnPropertyNames        DontEnum|Function 1
  69   keys                      objectConstructorKeys                       DontEnum|Function 1
  70   defineProperty            objectConstructorDefineProperty             DontEnum|Function 3
  71   defineProperties          objectConstructorDefineProperties           DontEnum|Function 2
  72   create                    objectConstructorCreate                     DontEnum|Function 2
  73   seal                      objectConstructorSeal                       DontEnum|Function 1
  74   freeze                    objectConstructorFreeze                     DontEnum|Function 1
  75   preventExtensions         objectConstructorPreventExtensions          DontEnum|Function 1
  76   isSealed                  objectConstructorIsSealed                   DontEnum|Function 1
  77   isFrozen                  objectConstructorIsFrozen                   DontEnum|Function 1
  78   isExtensible              objectConstructorIsExtensible               DontEnum|Function 1
  79 @end
  80 */
  81
  82 ObjectConstructor::ObjectConstructor(VM& vm, Structure* structure)
  83     : InternalFunction(vm, structure)
  84 {
  85 }
  86
  87 void ObjectConstructor::finishCreation(VM& vm, ObjectPrototype* objectPrototype)
  88 {
  89     Base::finishCreation(vm, Identifier(&vm, "Object").string());
  90     // ECMA 15.2.3.1
  91     putDirectWithoutTransition(vm, vm.propertyNames->prototype, objectPrototype, DontEnum | DontDelete | ReadOnly);
  92     // no. of arguments for constructor
  93     putDirectWithoutTransition(vm, vm.propertyNames->length, jsNumber(1), ReadOnly | DontEnum | DontDelete);
  94 }
  95
  96 bool ObjectConstructor::getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot &slot)
  97 {
  98     return getStaticFunctionSlot<JSObject>(exec, ExecState::objectConstructorTable(exec->vm()), jsCast<ObjectConstructor*>(object), propertyName, slot);
  99 }
 100
 101 static ALWAYS_INLINE JSObject* constructObject(ExecState* exec)
 102 {
 103     JSGlobalObject* globalObject = exec->callee()->globalObject();
 104     ArgList args(exec);
 105     JSValue arg = args.at(0);
 106     if (arg.isUndefinedOrNull())
 107         return constructEmptyObject(exec, globalObject->objectPrototype());
 108     return arg.toObject(exec, globalObject);
 109 }
 110
 111 static EncodedJSValue JSC_HOST_CALL constructWithObjectConstructor(ExecState* exec)
 112 {
 113     return JSValue::encode(constructObject(exec));
 114 }
 115
 116 ConstructType ObjectConstructor::getConstructData(JSCell*, ConstructData& constructData)
 117 {
 118     constructData.native.function = constructWithObjectConstructor;
 119     return ConstructTypeHost;
 120 }
 121
 122 static EncodedJSValue JSC_HOST_CALL callObjectConstructor(ExecState* exec)
 123 {
 124     return JSValue::encode(constructObject(exec));
 125 }
 126
 127 CallType ObjectConstructor::getCallData(JSCell*, CallData& callData)
 128 {
 129     callData.native.function = callObjectConstructor;
 130     return CallTypeHost;
 131 }
 132
 133 class ObjectConstructorGetPrototypeOfFunctor {
 134 public:
 135     ObjectConstructorGetPrototypeOfFunctor(JSObject* object)
 136         : m_hasSkippedFirstFrame(false)
 137         , m_object(object)
 138         , m_result(JSValue::encode(jsUndefined()))
 139     {
 140     }
 141
 142     EncodedJSValue result() const { return m_result; }
 143
 144     StackVisitor::Status operator()(StackVisitor& visitor)
 145     {
 146         if (!m_hasSkippedFirstFrame) {
 147             m_hasSkippedFirstFrame = true;
 148             return StackVisitor::Continue;
 149         }
 150
 151     if (m_object->allowsAccessFrom(visitor->callFrame()))
 152         m_result = JSValue::encode(m_object->prototype());
 153     return StackVisitor::Done;
 154 }
 155
 156 private:
 157     bool m_hasSkippedFirstFrame;
 158     JSObject* m_object;
 159     EncodedJSValue m_result;
 160 };
 161
 162 EncodedJSValue JSC_HOST_CALL objectConstructorGetPrototypeOf(ExecState* exec)
 163 {
 164     if (!exec->argument(0).isObject())
 165         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Requested prototype of a value that is not an object.")));
 166     JSObject* object = asObject(exec->argument(0));
 167     ObjectConstructorGetPrototypeOfFunctor functor(object);
 168     exec->iterate(functor);
 169     return functor.result();
 170 }
 171
 172 EncodedJSValue JSC_HOST_CALL objectConstructorGetOwnPropertyDescriptor(ExecState* exec)
 173 {
 174     if (!exec->argument(0).isObject())
 175         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Requested property descriptor of a value that is not an object.")));
 176     String propertyName = exec->argument(1).toString(exec)->value(exec);
 177     if (exec->hadException())
 178         return JSValue::encode(jsNull());
 179     JSObject* object = asObject(exec->argument(0));
 180     PropertyDescriptor descriptor;
 181     if (!object->getOwnPropertyDescriptor(exec, Identifier(exec, propertyName), descriptor))
 182         return JSValue::encode(jsUndefined());
 183     if (exec->hadException())
 184         return JSValue::encode(jsUndefined());
 185
 186     JSObject* description = constructEmptyObject(exec);
 187     if (!descriptor.isAccessorDescriptor()) {
 188         description->putDirect(exec->vm(), exec->propertyNames().value, descriptor.value() ? descriptor.value() : jsUndefined(), 0);
 189         description->putDirect(exec->vm(), exec->propertyNames().writable, jsBoolean(descriptor.writable()), 0);
 190     } else {
 191         ASSERT(descriptor.getter());
 192         ASSERT(descriptor.setter());
 193         description->putDirect(exec->vm(), exec->propertyNames().get, descriptor.getter(), 0);
 194         description->putDirect(exec->vm(), exec->propertyNames().set, descriptor.setter(), 0);
 195     }
 196
 197     description->putDirect(exec->vm(), exec->propertyNames().enumerable, jsBoolean(descriptor.enumerable()), 0);
 198     description->putDirect(exec->vm(), exec->propertyNames().configurable, jsBoolean(descriptor.configurable()), 0);
 199
 200     return JSValue::encode(description);
 201 }
 202
 203 // FIXME: Use the enumeration cache.
 204 EncodedJSValue JSC_HOST_CALL objectConstructorGetOwnPropertyNames(ExecState* exec)
 205 {
 206     if (!exec->argument(0).isObject())
 207         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Requested property names of a value that is not an object.")));
 208     PropertyNameArray properties(exec);
 209     asObject(exec->argument(0))->methodTable(exec->vm())->getOwnPropertyNames(asObject(exec->argument(0)), exec, properties, IncludeDontEnumProperties);
 210     JSArray* names = constructEmptyArray(exec, 0);
 211     size_t numProperties = properties.size();
 212     for (size_t i = 0; i < numProperties; i++)
 213         names->push(exec, jsOwnedString(exec, properties[i].string()));
 214     return JSValue::encode(names);
 215 }
 216
 217 // FIXME: Use the enumeration cache.
 218 EncodedJSValue JSC_HOST_CALL objectConstructorKeys(ExecState* exec)
 219 {
 220     if (!exec->argument(0).isObject())
 221         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Requested keys of a value that is not an object.")));
 222     PropertyNameArray properties(exec);
 223     asObject(exec->argument(0))->methodTable(exec->vm())->getOwnPropertyNames(asObject(exec->argument(0)), exec, properties, ExcludeDontEnumProperties);
 224     JSArray* keys = constructEmptyArray(exec, 0);
 225     size_t numProperties = properties.size();
 226     for (size_t i = 0; i < numProperties; i++)
 227         keys->push(exec, jsOwnedString(exec, properties[i].string()));
 228     return JSValue::encode(keys);
 229 }
 230
 231 // ES5 8.10.5 ToPropertyDescriptor
 232 static bool toPropertyDescriptor(ExecState* exec, JSValue in, PropertyDescriptor& desc)
 233 {
 234     if (!in.isObject()) {
 235         exec->vm().throwException(exec, createTypeError(exec, ASCIILiteral("Property description must be an object.")));
 236         return false;
 237     }
 238     JSObject* description = asObject(in);
 239
 240     PropertySlot enumerableSlot(description);
 241     if (description->getPropertySlot(exec, exec->propertyNames().enumerable, enumerableSlot)) {
 242         desc.setEnumerable(enumerableSlot.getValue(exec, exec->propertyNames().enumerable).toBoolean(exec));
 243         if (exec->hadException())
 244             return false;
 245     }
 246
 247     PropertySlot configurableSlot(description);
 248     if (description->getPropertySlot(exec, exec->propertyNames().configurable, configurableSlot)) {
 249         desc.setConfigurable(configurableSlot.getValue(exec, exec->propertyNames().configurable).toBoolean(exec));
 250         if (exec->hadException())
 251             return false;
 252     }
 253
 254     JSValue value;
 255     PropertySlot valueSlot(description);
 256     if (description->getPropertySlot(exec, exec->propertyNames().value, valueSlot)) {
 257         desc.setValue(valueSlot.getValue(exec, exec->propertyNames().value));
 258         if (exec->hadException())
 259             return false;
 260     }
 261
 262     PropertySlot writableSlot(description);
 263     if (description->getPropertySlot(exec, exec->propertyNames().writable, writableSlot)) {
 264         desc.setWritable(writableSlot.getValue(exec, exec->propertyNames().writable).toBoolean(exec));
 265         if (exec->hadException())
 266             return false;
 267     }
 268
 269     PropertySlot getSlot(description);
 270     if (description->getPropertySlot(exec, exec->propertyNames().get, getSlot)) {
 271         JSValue get = getSlot.getValue(exec, exec->propertyNames().get);
 272         if (exec->hadException())
 273             return false;
 274         if (!get.isUndefined()) {
 275             CallData callData;
 276             if (getCallData(get, callData) == CallTypeNone) {
 277                 exec->vm().throwException(exec, createTypeError(exec, ASCIILiteral("Getter must be a function.")));
 278                 return false;
 279             }
 280         }
 281         desc.setGetter(get);
 282     }
 283
 284     PropertySlot setSlot(description);
 285     if (description->getPropertySlot(exec, exec->propertyNames().set, setSlot)) {
 286         JSValue set = setSlot.getValue(exec, exec->propertyNames().set);
 287         if (exec->hadException())
 288             return false;
 289         if (!set.isUndefined()) {
 290             CallData callData;
 291             if (getCallData(set, callData) == CallTypeNone) {
 292                 exec->vm().throwException(exec, createTypeError(exec, ASCIILiteral("Setter must be a function.")));
 293                 return false;
 294             }
 295         }
 296         desc.setSetter(set);
 297     }
 298
 299     if (!desc.isAccessorDescriptor())
 300         return true;
 301
 302     if (desc.value()) {
 303         exec->vm().throwException(exec, createTypeError(exec, ASCIILiteral("Invalid property.  'value' present on property with getter or setter.")));
 304         return false;
 305     }
 306
 307     if (desc.writablePresent()) {
 308         exec->vm().throwException(exec, createTypeError(exec, ASCIILiteral("Invalid property.  'writable' present on property with getter or setter.")));
 309         return false;
 310     }
 311     return true;
 312 }
 313
 314 EncodedJSValue JSC_HOST_CALL objectConstructorDefineProperty(ExecState* exec)
 315 {
 316     if (!exec->argument(0).isObject())
 317         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Properties can only be defined on Objects.")));
 318     JSObject* O = asObject(exec->argument(0));
 319     String propertyName = exec->argument(1).toString(exec)->value(exec);
 320     if (exec->hadException())
 321         return JSValue::encode(jsNull());
 322     PropertyDescriptor descriptor;
 323     if (!toPropertyDescriptor(exec, exec->argument(2), descriptor))
 324         return JSValue::encode(jsNull());
 325     ASSERT((descriptor.attributes() & Accessor) || (!descriptor.isAccessorDescriptor()));
 326     ASSERT(!exec->hadException());
 327     O->methodTable(exec->vm())->defineOwnProperty(O, exec, Identifier(exec, propertyName), descriptor, true);
 328     return JSValue::encode(O);
 329 }
 330
 331 static JSValue defineProperties(ExecState* exec, JSObject* object, JSObject* properties)
 332 {
 333     PropertyNameArray propertyNames(exec);
 334     asObject(properties)->methodTable(exec->vm())->getOwnPropertyNames(asObject(properties), exec, propertyNames, ExcludeDontEnumProperties);
 335     size_t numProperties = propertyNames.size();
 336     Vector<PropertyDescriptor> descriptors;
 337     MarkedArgumentBuffer markBuffer;
 338     for (size_t i = 0; i < numProperties; i++) {
 339         JSValue prop = properties->get(exec, propertyNames[i]);
 340         if (exec->hadException())
 341             return jsNull();
 342         PropertyDescriptor descriptor;
 343         if (!toPropertyDescriptor(exec, prop, descriptor))
 344             return jsNull();
 345         descriptors.append(descriptor);
 346         // Ensure we mark all the values that we're accumulating
 347         if (descriptor.isDataDescriptor() && descriptor.value())
 348             markBuffer.append(descriptor.value());
 349         if (descriptor.isAccessorDescriptor()) {
 350             if (descriptor.getter())
 351                 markBuffer.append(descriptor.getter());
 352             if (descriptor.setter())
 353                 markBuffer.append(descriptor.setter());
 354         }
 355     }
 356     for (size_t i = 0; i < numProperties; i++) {
 357         object->methodTable(exec->vm())->defineOwnProperty(object, exec, propertyNames[i], descriptors[i], true);
 358         if (exec->hadException())
 359             return jsNull();
 360     }
 361     return object;
 362 }
 363
 364 EncodedJSValue JSC_HOST_CALL objectConstructorDefineProperties(ExecState* exec)
 365 {
 366     if (!exec->argument(0).isObject())
 367         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Properties can only be defined on Objects.")));
 368     return JSValue::encode(defineProperties(exec, asObject(exec->argument(0)), exec->argument(1).toObject(exec)));
 369 }
 370
 371 EncodedJSValue JSC_HOST_CALL objectConstructorCreate(ExecState* exec)
 372 {
 373     JSValue proto = exec->argument(0);
 374     if (!proto.isObject() && !proto.isNull())
 375         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object prototype may only be an Object or null.")));
 376     JSObject* newObject = proto.isObject()
 377         ? constructEmptyObject(exec, asObject(proto))
 378         : constructEmptyObject(exec, exec->lexicalGlobalObject()->nullPrototypeObjectStructure());
 379     if (exec->argument(1).isUndefined())
 380         return JSValue::encode(newObject);
 381     if (!exec->argument(1).isObject())
 382         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Property descriptor list must be an Object.")));
 383     return JSValue::encode(defineProperties(exec, newObject, asObject(exec->argument(1))));
 384 }
 385
 386 EncodedJSValue JSC_HOST_CALL objectConstructorSeal(ExecState* exec)
 387 {
 388     // 1. If Type(O) is not Object throw a TypeError exception.
 389     JSValue obj = exec->argument(0);
 390     if (!obj.isObject())
 391         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.seal can only be called on Objects.")));
 392     JSObject* object = asObject(obj);
 393
 394     if (isJSFinalObject(object)) {
 395         object->seal(exec->vm());
 396         return JSValue::encode(obj);
 397     }
 398
 399     // 2. For each named own property name P of O,
 400     PropertyNameArray properties(exec);
 401     object->methodTable(exec->vm())->getOwnPropertyNames(object, exec, properties, IncludeDontEnumProperties);
 402     PropertyNameArray::const_iterator end = properties.end();
 403     for (PropertyNameArray::const_iterator iter = properties.begin(); iter != end; ++iter) {
 404         // a. Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
 405         PropertyDescriptor desc;
 406         if (!object->getOwnPropertyDescriptor(exec, *iter, desc))
 407             continue;
 408         // b. If desc.[[Configurable]] is true, set desc.[[Configurable]] to false.
 409         desc.setConfigurable(false);
 410         // c. Call the [[DefineOwnProperty]] internal method of O with P, desc, and true as arguments.
 411         object->methodTable(exec->vm())->defineOwnProperty(object, exec, *iter, desc, true);
 412         if (exec->hadException())
 413             return JSValue::encode(obj);
 414     }
 415
 416     // 3. Set the [[Extensible]] internal property of O to false.
 417     object->preventExtensions(exec->vm());
 418
 419     // 4. Return O.
 420     return JSValue::encode(obj);
 421 }
 422
 423 EncodedJSValue JSC_HOST_CALL objectConstructorFreeze(ExecState* exec)
 424 {
 425     // 1. If Type(O) is not Object throw a TypeError exception.
 426     JSValue obj = exec->argument(0);
 427     if (!obj.isObject())
 428         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.freeze can only be called on Objects.")));
 429     JSObject* object = asObject(obj);
 430
 431     if (isJSFinalObject(object) && !hasIndexedProperties(object->indexingType())) {
 432         object->freeze(exec->vm());
 433         return JSValue::encode(obj);
 434     }
 435
 436     // 2. For each named own property name P of O,
 437     PropertyNameArray properties(exec);
 438     object->methodTable(exec->vm())->getOwnPropertyNames(object, exec, properties, IncludeDontEnumProperties);
 439     PropertyNameArray::const_iterator end = properties.end();
 440     for (PropertyNameArray::const_iterator iter = properties.begin(); iter != end; ++iter) {
 441         // a. Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
 442         PropertyDescriptor desc;
 443         if (!object->getOwnPropertyDescriptor(exec, *iter, desc))
 444             continue;
 445         // b. If IsDataDescriptor(desc) is true, then
 446         // i. If desc.[[Writable]] is true, set desc.[[Writable]] to false.
 447         if (desc.isDataDescriptor())
 448             desc.setWritable(false);
 449         // c. If desc.[[Configurable]] is true, set desc.[[Configurable]] to false.
 450         desc.setConfigurable(false);
 451         // d. Call the [[DefineOwnProperty]] internal method of O with P, desc, and true as arguments.
 452         object->methodTable(exec->vm())->defineOwnProperty(object, exec, *iter, desc, true);
 453         if (exec->hadException())
 454             return JSValue::encode(obj);
 455     }
 456
 457     // 3. Set the [[Extensible]] internal property of O to false.
 458     object->preventExtensions(exec->vm());
 459
 460     // 4. Return O.
 461     return JSValue::encode(obj);
 462 }
 463
 464 EncodedJSValue JSC_HOST_CALL objectConstructorPreventExtensions(ExecState* exec)
 465 {
 466     JSValue obj = exec->argument(0);
 467     if (!obj.isObject())
 468         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.preventExtensions can only be called on Objects.")));
 469     asObject(obj)->preventExtensions(exec->vm());
 470     return JSValue::encode(obj);
 471 }
 472
 473 EncodedJSValue JSC_HOST_CALL objectConstructorIsSealed(ExecState* exec)
 474 {
 475     // 1. If Type(O) is not Object throw a TypeError exception.
 476     JSValue obj = exec->argument(0);
 477     if (!obj.isObject())
 478         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.isSealed can only be called on Objects.")));
 479     JSObject* object = asObject(obj);
 480
 481     if (isJSFinalObject(object))
 482         return JSValue::encode(jsBoolean(object->isSealed(exec->vm())));
 483
 484     // 2. For each named own property name P of O,
 485     PropertyNameArray properties(exec);
 486     object->methodTable(exec->vm())->getOwnPropertyNames(object, exec, properties, IncludeDontEnumProperties);
 487     PropertyNameArray::const_iterator end = properties.end();
 488     for (PropertyNameArray::const_iterator iter = properties.begin(); iter != end; ++iter) {
 489         // a. Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
 490         PropertyDescriptor desc;
 491         if (!object->getOwnPropertyDescriptor(exec, *iter, desc))
 492             continue;
 493         // b. If desc.[[Configurable]] is true, then return false.
 494         if (desc.configurable())
 495             return JSValue::encode(jsBoolean(false));
 496     }
 497
 498     // 3. If the [[Extensible]] internal property of O is false, then return true.
 499     // 4. Otherwise, return false.
 500     return JSValue::encode(jsBoolean(!object->isExtensible()));
 501 }
 502
 503 EncodedJSValue JSC_HOST_CALL objectConstructorIsFrozen(ExecState* exec)
 504 {
 505     // 1. If Type(O) is not Object throw a TypeError exception.
 506     JSValue obj = exec->argument(0);
 507     if (!obj.isObject())
 508         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.isFrozen can only be called on Objects.")));
 509     JSObject* object = asObject(obj);
 510
 511     if (isJSFinalObject(object))
 512         return JSValue::encode(jsBoolean(object->isFrozen(exec->vm())));
 513
 514     // 2. For each named own property name P of O,
 515     PropertyNameArray properties(exec);
 516     object->methodTable(exec->vm())->getOwnPropertyNames(object, exec, properties, IncludeDontEnumProperties);
 517     PropertyNameArray::const_iterator end = properties.end();
 518     for (PropertyNameArray::const_iterator iter = properties.begin(); iter != end; ++iter) {
 519         // a. Let desc be the result of calling the [[GetOwnProperty]] internal method of O with P.
 520         PropertyDescriptor desc;
 521         if (!object->getOwnPropertyDescriptor(exec, *iter, desc))
 522             continue;
 523         // b. If IsDataDescriptor(desc) is true then
 524         // i. If desc.[[Writable]] is true, return false. c. If desc.[[Configurable]] is true, then return false.
 525         if ((desc.isDataDescriptor() && desc.writable()) || desc.configurable())
 526             return JSValue::encode(jsBoolean(false));
 527     }
 528
 529     // 3. If the [[Extensible]] internal property of O is false, then return true.
 530     // 4. Otherwise, return false.
 531     return JSValue::encode(jsBoolean(!object->isExtensible()));
 532 }
 533
 534 EncodedJSValue JSC_HOST_CALL objectConstructorIsExtensible(ExecState* exec)
 535 {
 536     JSValue obj = exec->argument(0);
 537     if (!obj.isObject())
 538         return throwVMError(exec, createTypeError(exec, ASCIILiteral("Object.isExtensible can only be called on Objects.")));
 539     return JSValue::encode(jsBoolean(asObject(obj)->isExtensible()));
 540 }
 541
 542 } // namespace JSC