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1 /*
2  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
3  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include "APICast.h"
28 #include "Error.h"
29 #include "JSCallbackFunction.h"
30 #include "JSClassRef.h"
31 #include "JSGlobalObject.h"
32 #include "JSLock.h"
33 #include "JSObjectRef.h"
34 #include "JSString.h"
35 #include "JSStringRef.h"
36 #include "OpaqueJSString.h"
37 #include "PropertyNameArray.h"
38 #include <wtf/Vector.h>
39 
40 namespace JSC {
41 
42 template <class Base>
asCallbackObject(JSValue value)43 inline JSCallbackObject<Base>* JSCallbackObject<Base>::asCallbackObject(JSValue value)
44 {
45     ASSERT(asObject(value)->inherits(&info));
46     return static_cast<JSCallbackObject*>(asObject(value));
47 }
48 
49 template <class Base>
JSCallbackObject(ExecState * exec,PassRefPtr<Structure> structure,JSClassRef jsClass,void * data)50 JSCallbackObject<Base>::JSCallbackObject(ExecState* exec, PassRefPtr<Structure> structure, JSClassRef jsClass, void* data)
51     : Base(structure)
52     , m_callbackObjectData(new JSCallbackObjectData(data, jsClass))
53 {
54     init(exec);
55 }
56 
57 // Global object constructor.
58 // FIXME: Move this into a separate JSGlobalCallbackObject class derived from this one.
59 template <class Base>
JSCallbackObject(JSClassRef jsClass)60 JSCallbackObject<Base>::JSCallbackObject(JSClassRef jsClass)
61     : Base()
62     , m_callbackObjectData(new JSCallbackObjectData(0, jsClass))
63 {
64     ASSERT(Base::isGlobalObject());
65     init(static_cast<JSGlobalObject*>(this)->globalExec());
66 }
67 
68 template <class Base>
init(ExecState * exec)69 void JSCallbackObject<Base>::init(ExecState* exec)
70 {
71     ASSERT(exec);
72 
73     Vector<JSObjectInitializeCallback, 16> initRoutines;
74     JSClassRef jsClass = classRef();
75     do {
76         if (JSObjectInitializeCallback initialize = jsClass->initialize)
77             initRoutines.append(initialize);
78     } while ((jsClass = jsClass->parentClass));
79 
80     // initialize from base to derived
81     for (int i = static_cast<int>(initRoutines.size()) - 1; i >= 0; i--) {
82         JSLock::DropAllLocks dropAllLocks(exec);
83         JSObjectInitializeCallback initialize = initRoutines[i];
84         initialize(toRef(exec), toRef(this));
85     }
86 }
87 
88 template <class Base>
~JSCallbackObject()89 JSCallbackObject<Base>::~JSCallbackObject()
90 {
91     JSObjectRef thisRef = toRef(this);
92 
93     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass)
94         if (JSObjectFinalizeCallback finalize = jsClass->finalize)
95             finalize(thisRef);
96 }
97 
98 template <class Base>
className()99 UString JSCallbackObject<Base>::className() const
100 {
101     UString thisClassName = classRef()->className();
102     if (!thisClassName.isEmpty())
103         return thisClassName;
104 
105     return Base::className();
106 }
107 
108 template <class Base>
getOwnPropertySlot(ExecState * exec,const Identifier & propertyName,PropertySlot & slot)109 bool JSCallbackObject<Base>::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
110 {
111     JSContextRef ctx = toRef(exec);
112     JSObjectRef thisRef = toRef(this);
113     RefPtr<OpaqueJSString> propertyNameRef;
114 
115     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
116         // optional optimization to bypass getProperty in cases when we only need to know if the property exists
117         if (JSObjectHasPropertyCallback hasProperty = jsClass->hasProperty) {
118             if (!propertyNameRef)
119                 propertyNameRef = OpaqueJSString::create(propertyName.ustring());
120             JSLock::DropAllLocks dropAllLocks(exec);
121             if (hasProperty(ctx, thisRef, propertyNameRef.get())) {
122                 slot.setCustom(this, callbackGetter);
123                 return true;
124             }
125         } else if (JSObjectGetPropertyCallback getProperty = jsClass->getProperty) {
126             if (!propertyNameRef)
127                 propertyNameRef = OpaqueJSString::create(propertyName.ustring());
128             JSValueRef exception = 0;
129             JSValueRef value;
130             {
131                 JSLock::DropAllLocks dropAllLocks(exec);
132                 value = getProperty(ctx, thisRef, propertyNameRef.get(), &exception);
133             }
134             exec->setException(toJS(exec, exception));
135             if (value) {
136                 slot.setValue(toJS(exec, value));
137                 return true;
138             }
139             if (exception) {
140                 slot.setValue(jsUndefined());
141                 return true;
142             }
143         }
144 
145         if (OpaqueJSClassStaticValuesTable* staticValues = jsClass->staticValues(exec)) {
146             if (staticValues->contains(propertyName.ustring().rep())) {
147                 slot.setCustom(this, staticValueGetter);
148                 return true;
149             }
150         }
151 
152         if (OpaqueJSClassStaticFunctionsTable* staticFunctions = jsClass->staticFunctions(exec)) {
153             if (staticFunctions->contains(propertyName.ustring().rep())) {
154                 slot.setCustom(this, staticFunctionGetter);
155                 return true;
156             }
157         }
158     }
159 
160     return Base::getOwnPropertySlot(exec, propertyName, slot);
161 }
162 
163 template <class Base>
getOwnPropertySlot(ExecState * exec,unsigned propertyName,PropertySlot & slot)164 bool JSCallbackObject<Base>::getOwnPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
165 {
166     return getOwnPropertySlot(exec, Identifier::from(exec, propertyName), slot);
167 }
168 
169 template <class Base>
put(ExecState * exec,const Identifier & propertyName,JSValue value,PutPropertySlot & slot)170 void JSCallbackObject<Base>::put(ExecState* exec, const Identifier& propertyName, JSValue value, PutPropertySlot& slot)
171 {
172     JSContextRef ctx = toRef(exec);
173     JSObjectRef thisRef = toRef(this);
174     RefPtr<OpaqueJSString> propertyNameRef;
175     JSValueRef valueRef = toRef(exec, value);
176 
177     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
178         if (JSObjectSetPropertyCallback setProperty = jsClass->setProperty) {
179             if (!propertyNameRef)
180                 propertyNameRef = OpaqueJSString::create(propertyName.ustring());
181             JSValueRef exception = 0;
182             bool result;
183             {
184                 JSLock::DropAllLocks dropAllLocks(exec);
185                 result = setProperty(ctx, thisRef, propertyNameRef.get(), valueRef, &exception);
186             }
187             exec->setException(toJS(exec, exception));
188             if (result || exception)
189                 return;
190         }
191 
192         if (OpaqueJSClassStaticValuesTable* staticValues = jsClass->staticValues(exec)) {
193             if (StaticValueEntry* entry = staticValues->get(propertyName.ustring().rep())) {
194                 if (entry->attributes & kJSPropertyAttributeReadOnly)
195                     return;
196                 if (JSObjectSetPropertyCallback setProperty = entry->setProperty) {
197                     if (!propertyNameRef)
198                         propertyNameRef = OpaqueJSString::create(propertyName.ustring());
199                     JSValueRef exception = 0;
200                     bool result;
201                     {
202                         JSLock::DropAllLocks dropAllLocks(exec);
203                         result = setProperty(ctx, thisRef, propertyNameRef.get(), valueRef, &exception);
204                     }
205                     exec->setException(toJS(exec, exception));
206                     if (result || exception)
207                         return;
208                 } else
209                     throwError(exec, ReferenceError, "Attempt to set a property that is not settable.");
210             }
211         }
212 
213         if (OpaqueJSClassStaticFunctionsTable* staticFunctions = jsClass->staticFunctions(exec)) {
214             if (StaticFunctionEntry* entry = staticFunctions->get(propertyName.ustring().rep())) {
215                 if (entry->attributes & kJSPropertyAttributeReadOnly)
216                     return;
217                 JSCallbackObject<Base>::putDirect(propertyName, value); // put as override property
218                 return;
219             }
220         }
221     }
222 
223     return Base::put(exec, propertyName, value, slot);
224 }
225 
226 template <class Base>
deleteProperty(ExecState * exec,const Identifier & propertyName)227 bool JSCallbackObject<Base>::deleteProperty(ExecState* exec, const Identifier& propertyName)
228 {
229     JSContextRef ctx = toRef(exec);
230     JSObjectRef thisRef = toRef(this);
231     RefPtr<OpaqueJSString> propertyNameRef;
232 
233     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
234         if (JSObjectDeletePropertyCallback deleteProperty = jsClass->deleteProperty) {
235             if (!propertyNameRef)
236                 propertyNameRef = OpaqueJSString::create(propertyName.ustring());
237             JSValueRef exception = 0;
238             bool result;
239             {
240                 JSLock::DropAllLocks dropAllLocks(exec);
241                 result = deleteProperty(ctx, thisRef, propertyNameRef.get(), &exception);
242             }
243             exec->setException(toJS(exec, exception));
244             if (result || exception)
245                 return true;
246         }
247 
248         if (OpaqueJSClassStaticValuesTable* staticValues = jsClass->staticValues(exec)) {
249             if (StaticValueEntry* entry = staticValues->get(propertyName.ustring().rep())) {
250                 if (entry->attributes & kJSPropertyAttributeDontDelete)
251                     return false;
252                 return true;
253             }
254         }
255 
256         if (OpaqueJSClassStaticFunctionsTable* staticFunctions = jsClass->staticFunctions(exec)) {
257             if (StaticFunctionEntry* entry = staticFunctions->get(propertyName.ustring().rep())) {
258                 if (entry->attributes & kJSPropertyAttributeDontDelete)
259                     return false;
260                 return true;
261             }
262         }
263     }
264 
265     return Base::deleteProperty(exec, propertyName);
266 }
267 
268 template <class Base>
deleteProperty(ExecState * exec,unsigned propertyName)269 bool JSCallbackObject<Base>::deleteProperty(ExecState* exec, unsigned propertyName)
270 {
271     return deleteProperty(exec, Identifier::from(exec, propertyName));
272 }
273 
274 template <class Base>
getConstructData(ConstructData & constructData)275 ConstructType JSCallbackObject<Base>::getConstructData(ConstructData& constructData)
276 {
277     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
278         if (jsClass->callAsConstructor) {
279             constructData.native.function = construct;
280             return ConstructTypeHost;
281         }
282     }
283     return ConstructTypeNone;
284 }
285 
286 template <class Base>
construct(ExecState * exec,JSObject * constructor,const ArgList & args)287 JSObject* JSCallbackObject<Base>::construct(ExecState* exec, JSObject* constructor, const ArgList& args)
288 {
289     JSContextRef execRef = toRef(exec);
290     JSObjectRef constructorRef = toRef(constructor);
291 
292     for (JSClassRef jsClass = static_cast<JSCallbackObject<Base>*>(constructor)->classRef(); jsClass; jsClass = jsClass->parentClass) {
293         if (JSObjectCallAsConstructorCallback callAsConstructor = jsClass->callAsConstructor) {
294             int argumentCount = static_cast<int>(args.size());
295             Vector<JSValueRef, 16> arguments(argumentCount);
296             for (int i = 0; i < argumentCount; i++)
297                 arguments[i] = toRef(exec, args.at(i));
298             JSValueRef exception = 0;
299             JSObject* result;
300             {
301                 JSLock::DropAllLocks dropAllLocks(exec);
302                 result = toJS(callAsConstructor(execRef, constructorRef, argumentCount, arguments.data(), &exception));
303             }
304             exec->setException(toJS(exec, exception));
305             return result;
306         }
307     }
308 
309     ASSERT_NOT_REACHED(); // getConstructData should prevent us from reaching here
310     return 0;
311 }
312 
313 template <class Base>
hasInstance(ExecState * exec,JSValue value,JSValue)314 bool JSCallbackObject<Base>::hasInstance(ExecState* exec, JSValue value, JSValue)
315 {
316     JSContextRef execRef = toRef(exec);
317     JSObjectRef thisRef = toRef(this);
318 
319     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
320         if (JSObjectHasInstanceCallback hasInstance = jsClass->hasInstance) {
321             JSValueRef valueRef = toRef(exec, value);
322             JSValueRef exception = 0;
323             bool result;
324             {
325                 JSLock::DropAllLocks dropAllLocks(exec);
326                 result = hasInstance(execRef, thisRef, valueRef, &exception);
327             }
328             exec->setException(toJS(exec, exception));
329             return result;
330         }
331     }
332     return false;
333 }
334 
335 template <class Base>
getCallData(CallData & callData)336 CallType JSCallbackObject<Base>::getCallData(CallData& callData)
337 {
338     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
339         if (jsClass->callAsFunction) {
340             callData.native.function = call;
341             return CallTypeHost;
342         }
343     }
344     return CallTypeNone;
345 }
346 
347 template <class Base>
call(ExecState * exec,JSObject * functionObject,JSValue thisValue,const ArgList & args)348 JSValue JSCallbackObject<Base>::call(ExecState* exec, JSObject* functionObject, JSValue thisValue, const ArgList& args)
349 {
350     JSContextRef execRef = toRef(exec);
351     JSObjectRef functionRef = toRef(functionObject);
352     JSObjectRef thisObjRef = toRef(thisValue.toThisObject(exec));
353 
354     for (JSClassRef jsClass = static_cast<JSCallbackObject<Base>*>(functionObject)->classRef(); jsClass; jsClass = jsClass->parentClass) {
355         if (JSObjectCallAsFunctionCallback callAsFunction = jsClass->callAsFunction) {
356             int argumentCount = static_cast<int>(args.size());
357             Vector<JSValueRef, 16> arguments(argumentCount);
358             for (int i = 0; i < argumentCount; i++)
359                 arguments[i] = toRef(exec, args.at(i));
360             JSValueRef exception = 0;
361             JSValue result;
362             {
363                 JSLock::DropAllLocks dropAllLocks(exec);
364                 result = toJS(exec, callAsFunction(execRef, functionRef, thisObjRef, argumentCount, arguments.data(), &exception));
365             }
366             exec->setException(toJS(exec, exception));
367             return result;
368         }
369     }
370 
371     ASSERT_NOT_REACHED(); // getCallData should prevent us from reaching here
372     return JSValue();
373 }
374 
375 template <class Base>
getPropertyNames(ExecState * exec,PropertyNameArray & propertyNames)376 void JSCallbackObject<Base>::getPropertyNames(ExecState* exec, PropertyNameArray& propertyNames)
377 {
378     JSContextRef execRef = toRef(exec);
379     JSObjectRef thisRef = toRef(this);
380 
381     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass) {
382         if (JSObjectGetPropertyNamesCallback getPropertyNames = jsClass->getPropertyNames) {
383             JSLock::DropAllLocks dropAllLocks(exec);
384             getPropertyNames(execRef, thisRef, toRef(&propertyNames));
385         }
386 
387         if (OpaqueJSClassStaticValuesTable* staticValues = jsClass->staticValues(exec)) {
388             typedef OpaqueJSClassStaticValuesTable::const_iterator iterator;
389             iterator end = staticValues->end();
390             for (iterator it = staticValues->begin(); it != end; ++it) {
391                 UString::Rep* name = it->first.get();
392                 StaticValueEntry* entry = it->second;
393                 if (entry->getProperty && !(entry->attributes & kJSPropertyAttributeDontEnum))
394                     propertyNames.add(Identifier(exec, name));
395             }
396         }
397 
398         if (OpaqueJSClassStaticFunctionsTable* staticFunctions = jsClass->staticFunctions(exec)) {
399             typedef OpaqueJSClassStaticFunctionsTable::const_iterator iterator;
400             iterator end = staticFunctions->end();
401             for (iterator it = staticFunctions->begin(); it != end; ++it) {
402                 UString::Rep* name = it->first.get();
403                 StaticFunctionEntry* entry = it->second;
404                 if (!(entry->attributes & kJSPropertyAttributeDontEnum))
405                     propertyNames.add(Identifier(exec, name));
406             }
407         }
408     }
409 
410     Base::getPropertyNames(exec, propertyNames);
411 }
412 
413 template <class Base>
toNumber(ExecState * exec)414 double JSCallbackObject<Base>::toNumber(ExecState* exec) const
415 {
416     // We need this check to guard against the case where this object is rhs of
417     // a binary expression where lhs threw an exception in its conversion to
418     // primitive
419     if (exec->hadException())
420         return NaN;
421     JSContextRef ctx = toRef(exec);
422     JSObjectRef thisRef = toRef(this);
423 
424     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass)
425         if (JSObjectConvertToTypeCallback convertToType = jsClass->convertToType) {
426             JSValueRef exception = 0;
427             JSValueRef value;
428             {
429                 JSLock::DropAllLocks dropAllLocks(exec);
430                 value = convertToType(ctx, thisRef, kJSTypeNumber, &exception);
431             }
432             if (exception) {
433                 exec->setException(toJS(exec, exception));
434                 return 0;
435             }
436 
437             double dValue;
438             return toJS(exec, value).getNumber(dValue) ? dValue : NaN;
439         }
440 
441     return Base::toNumber(exec);
442 }
443 
444 template <class Base>
toString(ExecState * exec)445 UString JSCallbackObject<Base>::toString(ExecState* exec) const
446 {
447     JSContextRef ctx = toRef(exec);
448     JSObjectRef thisRef = toRef(this);
449 
450     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass)
451         if (JSObjectConvertToTypeCallback convertToType = jsClass->convertToType) {
452             JSValueRef exception = 0;
453             JSValueRef value;
454             {
455                 JSLock::DropAllLocks dropAllLocks(exec);
456                 value = convertToType(ctx, thisRef, kJSTypeString, &exception);
457             }
458             if (exception) {
459                 exec->setException(toJS(exec, exception));
460                 return "";
461             }
462             return toJS(exec, value).getString();
463         }
464 
465     return Base::toString(exec);
466 }
467 
468 template <class Base>
setPrivate(void * data)469 void JSCallbackObject<Base>::setPrivate(void* data)
470 {
471     m_callbackObjectData->privateData = data;
472 }
473 
474 template <class Base>
getPrivate()475 void* JSCallbackObject<Base>::getPrivate()
476 {
477     return m_callbackObjectData->privateData;
478 }
479 
480 template <class Base>
inherits(JSClassRef c)481 bool JSCallbackObject<Base>::inherits(JSClassRef c) const
482 {
483     for (JSClassRef jsClass = classRef(); jsClass; jsClass = jsClass->parentClass)
484         if (jsClass == c)
485             return true;
486 
487     return false;
488 }
489 
490 template <class Base>
staticValueGetter(ExecState * exec,const Identifier & propertyName,const PropertySlot & slot)491 JSValue JSCallbackObject<Base>::staticValueGetter(ExecState* exec, const Identifier& propertyName, const PropertySlot& slot)
492 {
493     JSCallbackObject* thisObj = asCallbackObject(slot.slotBase());
494 
495     JSObjectRef thisRef = toRef(thisObj);
496     RefPtr<OpaqueJSString> propertyNameRef;
497 
498     for (JSClassRef jsClass = thisObj->classRef(); jsClass; jsClass = jsClass->parentClass)
499         if (OpaqueJSClassStaticValuesTable* staticValues = jsClass->staticValues(exec))
500             if (StaticValueEntry* entry = staticValues->get(propertyName.ustring().rep()))
501                 if (JSObjectGetPropertyCallback getProperty = entry->getProperty) {
502                     if (!propertyNameRef)
503                         propertyNameRef = OpaqueJSString::create(propertyName.ustring());
504                     JSValueRef exception = 0;
505                     JSValueRef value;
506                     {
507                         JSLock::DropAllLocks dropAllLocks(exec);
508                         value = getProperty(toRef(exec), thisRef, propertyNameRef.get(), &exception);
509                     }
510                     exec->setException(toJS(exec, exception));
511                     if (value)
512                         return toJS(exec, value);
513                     if (exception)
514                         return jsUndefined();
515                 }
516 
517     return throwError(exec, ReferenceError, "Static value property defined with NULL getProperty callback.");
518 }
519 
520 template <class Base>
staticFunctionGetter(ExecState * exec,const Identifier & propertyName,const PropertySlot & slot)521 JSValue JSCallbackObject<Base>::staticFunctionGetter(ExecState* exec, const Identifier& propertyName, const PropertySlot& slot)
522 {
523     JSCallbackObject* thisObj = asCallbackObject(slot.slotBase());
524 
525     // Check for cached or override property.
526     PropertySlot slot2(thisObj);
527     if (thisObj->Base::getOwnPropertySlot(exec, propertyName, slot2))
528         return slot2.getValue(exec, propertyName);
529 
530     for (JSClassRef jsClass = thisObj->classRef(); jsClass; jsClass = jsClass->parentClass) {
531         if (OpaqueJSClassStaticFunctionsTable* staticFunctions = jsClass->staticFunctions(exec)) {
532             if (StaticFunctionEntry* entry = staticFunctions->get(propertyName.ustring().rep())) {
533                 if (JSObjectCallAsFunctionCallback callAsFunction = entry->callAsFunction) {
534                     JSObject* o = new (exec) JSCallbackFunction(exec, callAsFunction, propertyName);
535                     thisObj->putDirect(propertyName, o, entry->attributes);
536                     return o;
537                 }
538             }
539         }
540     }
541 
542     return throwError(exec, ReferenceError, "Static function property defined with NULL callAsFunction callback.");
543 }
544 
545 template <class Base>
callbackGetter(ExecState * exec,const Identifier & propertyName,const PropertySlot & slot)546 JSValue JSCallbackObject<Base>::callbackGetter(ExecState* exec, const Identifier& propertyName, const PropertySlot& slot)
547 {
548     JSCallbackObject* thisObj = asCallbackObject(slot.slotBase());
549 
550     JSObjectRef thisRef = toRef(thisObj);
551     RefPtr<OpaqueJSString> propertyNameRef;
552 
553     for (JSClassRef jsClass = thisObj->classRef(); jsClass; jsClass = jsClass->parentClass)
554         if (JSObjectGetPropertyCallback getProperty = jsClass->getProperty) {
555             if (!propertyNameRef)
556                 propertyNameRef = OpaqueJSString::create(propertyName.ustring());
557             JSValueRef exception = 0;
558             JSValueRef value;
559             {
560                 JSLock::DropAllLocks dropAllLocks(exec);
561                 value = getProperty(toRef(exec), thisRef, propertyNameRef.get(), &exception);
562             }
563             exec->setException(toJS(exec, exception));
564             if (value)
565                 return toJS(exec, value);
566             if (exception)
567                 return jsUndefined();
568         }
569 
570     return throwError(exec, ReferenceError, "hasProperty callback returned true for a property that doesn't exist.");
571 }
572 
573 } // namespace JSC
574