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 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::visitChildren(SlotVisitor& visitor)
  99 {
 100     ASSERT_GC_OBJECT_INHERITS(this, &s_info);
 101     ASSERT(structure()->typeInfo().overridesVisitChildren());
 102     visitor.appendValues(m_jsStrings.get(), m_jsStringsSize, MayContainNullValues);
 103     if (m_cachedPrototypeChain)
 104         visitor.append(&m_cachedPrototypeChain);
 105 }
 106
 107 } // namespace JSC