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      1 /*
      2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      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  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include "config.h"
     30 #include "JSPropertyNameIterator.h"
     31 
     32 #include "JSGlobalObject.h"
     33 
     34 namespace JSC {
     35 
     36 ASSERT_CLASS_FITS_IN_CELL(JSPropertyNameIterator);
     37 
     38 const ClassInfo JSPropertyNameIterator::s_info = { "JSPropertyNameIterator", 0, 0, 0 };
     39 
     40 inline JSPropertyNameIterator::JSPropertyNameIterator(ExecState* exec, PropertyNameArrayData* propertyNameArrayData, size_t numCacheableSlots)
     41     : JSCell(exec->globalData(), exec->globalData().propertyNameIteratorStructure.get())
     42     , m_numCacheableSlots(numCacheableSlots)
     43     , m_jsStringsSize(propertyNameArrayData->propertyNameVector().size())
     44     , m_jsStrings(adoptArrayPtr(new WriteBarrier<Unknown>[m_jsStringsSize]))
     45 {
     46     PropertyNameArrayData::PropertyNameVector& propertyNameVector = propertyNameArrayData->propertyNameVector();
     47     for (size_t i = 0; i < m_jsStringsSize; ++i)
     48         m_jsStrings[i].set(exec->globalData(), this, jsOwnedString(exec, propertyNameVector[i].ustring()));
     49 }
     50 
     51 JSPropertyNameIterator* JSPropertyNameIterator::create(ExecState* exec, JSObject* o)
     52 {
     53     ASSERT(!o->structure()->enumerationCache() ||
     54             o->structure()->enumerationCache()->cachedStructure() != o->structure() ||
     55             o->structure()->enumerationCache()->cachedPrototypeChain() != o->structure()->prototypeChain(exec));
     56 
     57     PropertyNameArray propertyNames(exec);
     58     o->getPropertyNames(exec, propertyNames);
     59     size_t numCacheableSlots = 0;
     60     if (!o->structure()->hasNonEnumerableProperties() && !o->structure()->hasAnonymousSlots() &&
     61         !o->structure()->hasGetterSetterProperties() && !o->structure()->isUncacheableDictionary() &&
     62         !o->structure()->typeInfo().overridesGetPropertyNames())
     63         numCacheableSlots = o->structure()->propertyStorageSize();
     64 
     65     JSPropertyNameIterator* jsPropertyNameIterator = new (exec) JSPropertyNameIterator(exec, propertyNames.data(), numCacheableSlots);
     66 
     67     if (o->structure()->isDictionary())
     68         return jsPropertyNameIterator;
     69 
     70     if (o->structure()->typeInfo().overridesGetPropertyNames())
     71         return jsPropertyNameIterator;
     72 
     73     size_t count = normalizePrototypeChain(exec, o);
     74     StructureChain* structureChain = o->structure()->prototypeChain(exec);
     75     WriteBarrier<Structure>* structure = structureChain->head();
     76     for (size_t i = 0; i < count; ++i) {
     77         if (structure[i]->typeInfo().overridesGetPropertyNames())
     78             return jsPropertyNameIterator;
     79     }
     80 
     81     jsPropertyNameIterator->setCachedPrototypeChain(exec->globalData(), structureChain);
     82     jsPropertyNameIterator->setCachedStructure(exec->globalData(), o->structure());
     83     o->structure()->setEnumerationCache(exec->globalData(), jsPropertyNameIterator);
     84     return jsPropertyNameIterator;
     85 }
     86 
     87 JSValue JSPropertyNameIterator::get(ExecState* exec, JSObject* base, size_t i)
     88 {
     89     JSValue identifier = m_jsStrings[i].get();
     90     if (m_cachedStructure.get() == base->structure() && m_cachedPrototypeChain.get() == base->structure()->prototypeChain(exec))
     91         return identifier;
     92 
     93     if (!base->hasProperty(exec, Identifier(exec, asString(identifier)->value(exec))))
     94         return JSValue();
     95     return identifier;
     96 }
     97 
     98 void JSPropertyNameIterator::markChildren(MarkStack& markStack)
     99 {
    100     markStack.appendValues(m_jsStrings.get(), m_jsStringsSize, MayContainNullValues);
    101     if (m_cachedPrototypeChain)
    102         markStack.append(&m_cachedPrototypeChain);
    103 }
    104 
    105 } // namespace JSC
    106