runtime/JSPropertyNameIterator.cpp

   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