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/*
* Copyright (C) 2014-2022 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.
*/
#pragma once
#include "JSCast.h"
#include "Operations.h"
#include "PropertyNameArray.h"
#include "ResourceExhaustion.h"
#include "StructureChain.h"
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
class JSPropertyNameEnumerator final : public JSCell {
public:
using Base = JSCell;
static constexpr unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
enum Flag : uint8_t {
InitMode = 0,
IndexedMode = 1 << 0,
OwnStructureMode = 1 << 1,
GenericMode = 1 << 2,
// Profiling Only
HasSeenOwnStructureModeStructureMismatch = 1 << 3,
};
static constexpr uint8_t enumerationModeMask = (GenericMode << 1) - 1;
template<typename CellType, SubspaceAccess mode>
static GCClient::IsoSubspace* subspaceFor(VM& vm)
{
return &vm.propertyNameEnumeratorSpace();
}
static JSPropertyNameEnumerator* tryCreate(VM&, Structure*, uint32_t, uint32_t, PropertyNameArray&&);
static JSPropertyNameEnumerator* create(VM& vm, Structure* structure, uint32_t indexedLength, uint32_t numberStructureProperties, PropertyNameArray&& propertyNames)
{
auto* result = tryCreate(vm, structure, indexedLength, numberStructureProperties, WTFMove(propertyNames));
RELEASE_ASSERT_RESOURCE_AVAILABLE(result, MemoryExhaustion, "Crash intentionally because memory is exhausted.");
return result;
}
inline static Structure* createStructure(VM&, JSGlobalObject*, JSValue);
DECLARE_EXPORT_INFO;
JSString* propertyNameAtIndex(uint32_t index)
{
if (index >= sizeOfPropertyNames())
return nullptr;
return m_propertyNames.get()[index].get();
}
Structure* cachedStructure(VM& vm) const
{
UNUSED_PARAM(vm);
return m_cachedStructureID.get();
}
StructureID cachedStructureID() const { return m_cachedStructureID.value(); }
uint32_t indexedLength() const { return m_indexedLength; }
uint32_t endStructurePropertyIndex() const { return m_endStructurePropertyIndex; }
uint32_t endGenericPropertyIndex() const { return m_endGenericPropertyIndex; }
uint32_t cachedInlineCapacity() const { return m_cachedInlineCapacity; }
uint32_t sizeOfPropertyNames() const { return endGenericPropertyIndex(); }
uint32_t flags() const { return m_flags; }
static constexpr ptrdiff_t cachedStructureIDOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_cachedStructureID); }
static constexpr ptrdiff_t indexedLengthOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_indexedLength); }
static constexpr ptrdiff_t endStructurePropertyIndexOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_endStructurePropertyIndex); }
static constexpr ptrdiff_t endGenericPropertyIndexOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_endGenericPropertyIndex); }
static constexpr ptrdiff_t cachedInlineCapacityOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_cachedInlineCapacity); }
static constexpr ptrdiff_t flagsOffset() { return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_flags); }
static constexpr ptrdiff_t cachedPropertyNamesVectorOffset()
{
return OBJECT_OFFSETOF(JSPropertyNameEnumerator, m_propertyNames);
}
JSString* computeNext(JSGlobalObject*, JSObject* base, uint32_t& currentIndex, Flag&, bool shouldAllocateIndexedNameString = true);
DECLARE_VISIT_CHILDREN;
private:
friend class LLIntOffsetsExtractor;
JSPropertyNameEnumerator(VM&, Structure*, uint32_t, uint32_t, WriteBarrier<JSString>*, unsigned);
void finishCreation(VM&, RefPtr<PropertyNameArrayData>&&);
// JSPropertyNameEnumerator is immutable data structure, which allows VM to cache the empty one.
// After instantiating JSPropertyNameEnumerator, we must not change any fields.
AuxiliaryBarrier<WriteBarrier<JSString>*> m_propertyNames;
WriteBarrierStructureID m_cachedStructureID;
uint32_t m_indexedLength;
uint32_t m_endStructurePropertyIndex;
uint32_t m_endGenericPropertyIndex;
uint32_t m_cachedInlineCapacity;
uint32_t m_flags { 0 };
};
void getEnumerablePropertyNames(JSGlobalObject*, JSObject*, PropertyNameArray&, uint32_t& indexedLength, uint32_t& structurePropertyCount);
inline JSPropertyNameEnumerator* propertyNameEnumerator(JSGlobalObject* globalObject, JSObject* base)
{
VM& vm = getVM(globalObject);
auto scope = DECLARE_THROW_SCOPE(vm);
uint32_t indexedLength = base->getEnumerableLength();
Structure* structure = base->structure();
if (!indexedLength) {
uintptr_t enumeratorAndFlag = structure->cachedPropertyNameEnumeratorAndFlag();
if (enumeratorAndFlag) {
if (!(enumeratorAndFlag & StructureRareData::cachedPropertyNameEnumeratorIsValidatedViaTraversingFlag))
return std::bit_cast<JSPropertyNameEnumerator*>(enumeratorAndFlag);
structure->prototypeChain(vm, globalObject, base); // Refresh cached structure chain.
if (auto* enumerator = structure->cachedPropertyNameEnumerator())
return enumerator;
}
}
uint32_t numberStructureProperties = 0;
PropertyNameArray propertyNames(vm, PropertyNameMode::Strings, PrivateSymbolMode::Exclude);
getEnumerablePropertyNames(globalObject, base, propertyNames, indexedLength, numberStructureProperties);
RETURN_IF_EXCEPTION(scope, nullptr);
ASSERT(propertyNames.size() < UINT32_MAX);
bool sawPolyProto;
bool successfullyNormalizedChain = normalizePrototypeChain(globalObject, base, sawPolyProto) != InvalidPrototypeChain;
Structure* structureAfterGettingPropertyNames = base->structure();
if (!structureAfterGettingPropertyNames->canAccessPropertiesQuicklyForEnumeration()) {
indexedLength = 0;
numberStructureProperties = 0;
}
JSPropertyNameEnumerator* enumerator = nullptr;
if (!indexedLength && !propertyNames.size())
enumerator = vm.emptyPropertyNameEnumerator();
else {
enumerator = JSPropertyNameEnumerator::tryCreate(vm, structureAfterGettingPropertyNames, indexedLength, numberStructureProperties, WTFMove(propertyNames));
if (UNLIKELY(!enumerator)) {
throwOutOfMemoryError(globalObject, scope);
return nullptr;
}
}
if (!indexedLength && successfullyNormalizedChain && structureAfterGettingPropertyNames == structure) {
StructureChain* chain = structure->prototypeChain(vm, globalObject, base);
if (structure->canCachePropertyNameEnumerator(vm))
structure->setCachedPropertyNameEnumerator(vm, enumerator, chain);
}
return enumerator;
}
using EnumeratorMetadata = std::underlying_type_t<JSPropertyNameEnumerator::Flag>;
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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