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/*
* Copyright (C) 2014 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef JSPropertyNameEnumerator_h
#define JSPropertyNameEnumerator_h
#include "JSCell.h"
#include "Operations.h"
#include "PropertyNameArray.h"
#include "Structure.h"
namespace JSC {
class Identifier;
class JSPropertyNameEnumerator : public JSCell {
public:
typedef JSCell Base;
static JSPropertyNameEnumerator* create(VM&);
static JSPropertyNameEnumerator* create(VM&, Structure*, PropertyNameArray&);
static const bool needsDestruction = true;
static const bool hasImmortalStructure = true;
static void destroy(JSCell*);
static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
{
return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
}
DECLARE_EXPORT_INFO;
JSString* propertyNameAtIndex(uint32_t index) const
{
if (index >= m_propertyNames.size())
return nullptr;
return m_propertyNames[index].get();
}
RefCountedIdentifierSet* identifierSet() const
{
return m_identifierSet.get();
}
StructureChain* cachedPrototypeChain() const { return m_prototypeChain.get(); }
void setCachedPrototypeChain(VM& vm, StructureChain* prototypeChain) { return m_prototypeChain.set(vm, this, prototypeChain); }
Structure* cachedStructure(VM& vm) const
{
if (!m_cachedStructureID)
return nullptr;
return vm.heap.structureIDTable().get(m_cachedStructureID);
}
StructureID cachedStructureID() const { return m_cachedStructureID; }
uint32_t cachedInlineCapacity() const { return m_cachedInlineCapacity; }
static ptrdiff_t cachedStructureIDOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_cachedStructureID); }
static ptrdiff_t cachedInlineCapacityOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_cachedInlineCapacity); }
static ptrdiff_t cachedPropertyNamesLengthOffset()
{
return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_propertyNames) + Vector<WriteBarrier<JSString>>::sizeMemoryOffset();
}
static ptrdiff_t cachedPropertyNamesVectorOffset()
{
return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_propertyNames) + Vector<WriteBarrier<JSString>>::dataMemoryOffset();
}
static void visitChildren(JSCell*, SlotVisitor&);
private:
static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
JSPropertyNameEnumerator(VM&, StructureID, uint32_t, RefCountedIdentifierSet*);
void finishCreation(VM&, PassRefPtr<PropertyNameArrayData>);
Vector<WriteBarrier<JSString>> m_propertyNames;
RefPtr<RefCountedIdentifierSet> m_identifierSet;
StructureID m_cachedStructureID;
WriteBarrier<StructureChain> m_prototypeChain;
uint32_t m_cachedInlineCapacity;
};
inline JSPropertyNameEnumerator* structurePropertyNameEnumerator(ExecState* exec, JSObject* base, uint32_t length)
{
VM& vm = exec->vm();
Structure* structure = base->structure(vm);
if (JSPropertyNameEnumerator* enumerator = structure->cachedStructurePropertyNameEnumerator())
return enumerator;
if (!structure->canAccessPropertiesQuickly() || length != base->getArrayLength())
return JSPropertyNameEnumerator::create(vm);
PropertyNameArray propertyNames(exec);
base->methodTable(vm)->getStructurePropertyNames(base, exec, propertyNames, ExcludeDontEnumProperties);
JSPropertyNameEnumerator* enumerator = JSPropertyNameEnumerator::create(vm, structure, propertyNames);
if (structure->canCacheStructurePropertyNameEnumerator())
structure->setCachedStructurePropertyNameEnumerator(vm, enumerator);
return enumerator;
}
inline JSPropertyNameEnumerator* genericPropertyNameEnumerator(ExecState* exec, JSObject* base, uint32_t length, JSPropertyNameEnumerator* structureEnumerator)
{
VM& vm = exec->vm();
Structure* structure = base->structure(vm);
if (JSPropertyNameEnumerator* enumerator = structure->cachedGenericPropertyNameEnumerator()) {
if (!length && enumerator->cachedPrototypeChain() == structure->prototypeChain(exec))
return enumerator;
}
PropertyNameArray propertyNames(exec);
propertyNames.setPreviouslyEnumeratedLength(length);
propertyNames.setPreviouslyEnumeratedProperties(structureEnumerator);
// If we still have the same Structure that we started with, our Structure allows us to access its properties
// quickly (i.e. the Structure property loop was able to do things), and we iterated the full length of the
// object (i.e. there are no more own indexed properties that need to be enumerated), then the generic property
// iteration can skip any properties it would get from the JSObject base class. This turns out to be important
// for hot loops because most of our time is then dominated by trying to add the own Structure properties to
// the new generic PropertyNameArray and failing because we've already visited them.
Structure* cachedStructure = structureEnumerator->cachedStructure(vm);
if (structure == cachedStructure && structure->canAccessPropertiesQuickly() && static_cast<uint32_t>(length) == base->getArrayLength())
base->methodTable(vm)->getGenericPropertyNames(base, exec, propertyNames, ExcludeDontEnumProperties);
else
base->methodTable(vm)->getPropertyNames(base, exec, propertyNames, ExcludeDontEnumProperties);
normalizePrototypeChain(exec, base);
JSPropertyNameEnumerator* enumerator = JSPropertyNameEnumerator::create(vm, base->structure(vm), propertyNames);
enumerator->setCachedPrototypeChain(vm, structure->prototypeChain(exec));
if (!length && structure->canCacheGenericPropertyNameEnumerator())
structure->setCachedGenericPropertyNameEnumerator(vm, enumerator);
return enumerator;
}
} // namespace JSC
#endif // JSPropertyNameEnumerator_h
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