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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 inline JSPropertyNameIterator::JSPropertyNameIterator(ExecState* exec, PropertyNameArrayData* propertyNameArrayData, size_t numCacheableSlots)
     39     : JSCell(exec->globalData().propertyNameIteratorStructure.get())
     40     , m_cachedStructure(0)
     41     , m_numCacheableSlots(numCacheableSlots)
     42     , m_jsStringsSize(propertyNameArrayData->propertyNameVector().size())
     43     , m_jsStrings(new JSValue[m_jsStringsSize])
     44 {
     45     PropertyNameArrayData::PropertyNameVector& propertyNameVector = propertyNameArrayData->propertyNameVector();
     46     for (size_t i = 0; i < m_jsStringsSize; ++i)
     47         m_jsStrings[i] = jsOwnedString(exec, propertyNameVector[i].ustring());
     48 }
     49 
     50 JSPropertyNameIterator::~JSPropertyNameIterator()
     51 {
     52     if (m_cachedStructure)
     53         m_cachedStructure->clearEnumerationCache(this);
     54 }
     55 
     56 JSPropertyNameIterator* JSPropertyNameIterator::create(ExecState* exec, JSObject* o)
     57 {
     58     ASSERT(!o->structure()->enumerationCache() ||
     59             o->structure()->enumerationCache()->cachedStructure() != o->structure() ||
     60             o->structure()->enumerationCache()->cachedPrototypeChain() != o->structure()->prototypeChain(exec));
     61 
     62     PropertyNameArray propertyNames(exec);
     63     o->getPropertyNames(exec, propertyNames);
     64     size_t numCacheableSlots = 0;
     65     if (!o->structure()->hasNonEnumerableProperties() && !o->structure()->hasAnonymousSlots() &&
     66         !o->structure()->hasGetterSetterProperties() && !o->structure()->isUncacheableDictionary() &&
     67         !o->structure()->typeInfo().overridesGetPropertyNames())
     68         numCacheableSlots = o->structure()->propertyStorageSize();
     69 
     70     JSPropertyNameIterator* jsPropertyNameIterator = new (exec) JSPropertyNameIterator(exec, propertyNames.data(), numCacheableSlots);
     71 
     72     if (o->structure()->isDictionary())
     73         return jsPropertyNameIterator;
     74 
     75     if (o->structure()->typeInfo().overridesGetPropertyNames())
     76         return jsPropertyNameIterator;
     77 
     78     size_t count = normalizePrototypeChain(exec, o);
     79     StructureChain* structureChain = o->structure()->prototypeChain(exec);
     80     RefPtr<Structure>* structure = structureChain->head();
     81     for (size_t i = 0; i < count; ++i) {
     82         if (structure[i]->typeInfo().overridesGetPropertyNames())
     83             return jsPropertyNameIterator;
     84     }
     85 
     86     jsPropertyNameIterator->setCachedPrototypeChain(structureChain);
     87     jsPropertyNameIterator->setCachedStructure(o->structure());
     88     o->structure()->setEnumerationCache(jsPropertyNameIterator);
     89     return jsPropertyNameIterator;
     90 }
     91 
     92 JSValue JSPropertyNameIterator::get(ExecState* exec, JSObject* base, size_t i)
     93 {
     94     JSValue& identifier = m_jsStrings[i];
     95     if (m_cachedStructure == base->structure() && m_cachedPrototypeChain == base->structure()->prototypeChain(exec))
     96         return identifier;
     97 
     98     if (!base->hasProperty(exec, Identifier(exec, asString(identifier)->value(exec))))
     99         return JSValue();
    100     return identifier;
    101 }
    102 
    103 void JSPropertyNameIterator::markChildren(MarkStack& markStack)
    104 {
    105     markStack.appendValues(m_jsStrings.get(), m_jsStringsSize, MayContainNullValues);
    106 }
    107 
    108 } // namespace JSC
    109