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 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 "JSCInlines.h"
  33 #include "JSGlobalObject.h"
  34 #include <wtf/StdLibExtras.h>
  35
  36 namespace JSC {
  37
  38 const ClassInfo JSPropertyNameIterator::s_info = { "JSPropertyNameIterator", 0, 0, 0, CREATE_METHOD_TABLE(JSPropertyNameIterator) };
  39
  40 inline JSPropertyNameIterator::JSPropertyNameIterator(ExecState* exec, PropertyNameArrayData* propertyNameArrayData, size_t numCacheableSlots)
  41     : JSCell(exec->vm(), exec->vm().propertyNameIteratorStructure.get())
  42     , m_numCacheableSlots(numCacheableSlots)
  43     , m_jsStringsSize(propertyNameArrayData->propertyNameVector().size())
  44     , m_jsStrings(m_jsStringsSize ? std::make_unique<WriteBarrier<Unknown>[]>(m_jsStringsSize) : nullptr)
  45 {
  46 }
  47
  48 JSPropertyNameIterator* JSPropertyNameIterator::create(ExecState* exec, JSObject* o)
  49 {
  50     ASSERT(!o->structure()->enumerationCache() ||
  51             o->structure()->enumerationCache()->cachedStructure() != o->structure() ||
  52             o->structure()->enumerationCache()->cachedPrototypeChain() != o->structure()->prototypeChain(exec));
  53
  54     VM& vm = exec->vm();
  55
  56     PropertyNameArray propertyNames(exec);
  57     o->methodTable()->getPropertyNames(o, exec, propertyNames, ExcludeDontEnumProperties);
  58     size_t numCacheableSlots = 0;
  59     if (!o->structure()->hasNonEnumerableProperties() && !o->structure()->hasGetterSetterProperties()
  60         && !o->structure()->isUncacheableDictionary() && !o->structure()->typeInfo().overridesGetPropertyNames())
  61         numCacheableSlots = propertyNames.numCacheableSlots();
  62
  63     JSPropertyNameIterator* jsPropertyNameIterator = new (NotNull, allocateCell<JSPropertyNameIterator>(vm.heap)) JSPropertyNameIterator(exec, propertyNames.data(), numCacheableSlots);
  64     jsPropertyNameIterator->finishCreation(vm, propertyNames.data(), o);
  65
  66     if (o->structure()->isDictionary())
  67         return jsPropertyNameIterator;
  68
  69     if (o->structure()->typeInfo().overridesGetPropertyNames())
  70         return jsPropertyNameIterator;
  71
  72     if (hasIndexedProperties(o->indexingType()))
  73         return jsPropertyNameIterator;
  74
  75     size_t count = normalizePrototypeChain(exec, o);
  76     StructureChain* structureChain = o->structure()->prototypeChain(exec);
  77     WriteBarrier<Structure>* structure = structureChain->head();
  78     for (size_t i = 0; i < count; ++i) {
  79         if (structure[i]->typeInfo().overridesGetPropertyNames())
  80             return jsPropertyNameIterator;
  81     }
  82
  83     jsPropertyNameIterator->setCachedPrototypeChain(vm, structureChain);
  84     jsPropertyNameIterator->setCachedStructure(vm, o->structure());
  85     o->structure()->setEnumerationCache(vm, jsPropertyNameIterator);
  86     return jsPropertyNameIterator;
  87 }
  88
  89 void JSPropertyNameIterator::destroy(JSCell* cell)
  90 {
  91     static_cast<JSPropertyNameIterator*>(cell)->JSPropertyNameIterator::~JSPropertyNameIterator();
  92 }
  93
  94 JSValue JSPropertyNameIterator::get(ExecState* exec, JSObject* base, size_t i)
  95 {
  96     JSValue identifier = m_jsStrings[i].get();
  97     if (m_cachedStructure.get() == base->structure() && m_cachedPrototypeChain.get() == base->structure()->prototypeChain(exec))
  98         return identifier;
  99
 100     if (!base->hasProperty(exec, Identifier(exec, asString(identifier)->value(exec))))
 101         return JSValue();
 102     return identifier;
 103 }
 104
 105 void JSPropertyNameIterator::visitChildren(JSCell* cell, SlotVisitor& visitor)
 106 {
 107     JSPropertyNameIterator* thisObject = jsCast<JSPropertyNameIterator*>(cell);
 108     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
 109     ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
 110     visitor.appendValues(thisObject->m_jsStrings.get(), thisObject->m_jsStringsSize);
 111     visitor.append(&thisObject->m_cachedPrototypeChain);
 112 }
 113
 114 } // namespace JSC