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/*
* Copyright (C) 2014-2021 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.
*/
#include "config.h"
#include "JSPropertyNameEnumerator.h"
#include "JSObjectInlines.h"
namespace JSC {
const ClassInfo JSPropertyNameEnumerator::s_info = { "JSPropertyNameEnumerator"_s, nullptr, nullptr, nullptr, CREATE_METHOD_TABLE(JSPropertyNameEnumerator) };
JSPropertyNameEnumerator* JSPropertyNameEnumerator::create(VM& vm, Structure* structure, uint32_t indexedLength, uint32_t numberStructureProperties, PropertyNameArray&& propertyNames)
{
unsigned propertyNamesSize = propertyNames.size();
unsigned propertyNamesBufferSizeInBytes = Checked<unsigned>(propertyNamesSize) * sizeof(WriteBarrier<JSString>);
WriteBarrier<JSString>* propertyNamesBuffer = nullptr;
if (propertyNamesBufferSizeInBytes) {
propertyNamesBuffer = static_cast<WriteBarrier<JSString>*>(vm.jsValueGigacageAuxiliarySpace().allocate(vm, propertyNamesBufferSizeInBytes, nullptr, AllocationFailureMode::Assert));
for (unsigned i = 0; i < propertyNamesSize; ++i)
propertyNamesBuffer[i].clear();
}
JSPropertyNameEnumerator* enumerator = new (NotNull, allocateCell<JSPropertyNameEnumerator>(vm)) JSPropertyNameEnumerator(vm, structure, indexedLength, numberStructureProperties, propertyNamesBuffer, propertyNamesSize);
enumerator->finishCreation(vm, propertyNames.releaseData());
return enumerator;
}
JSPropertyNameEnumerator::JSPropertyNameEnumerator(VM& vm, Structure* structure, uint32_t indexedLength, uint32_t numberStructureProperties, WriteBarrier<JSString>* propertyNamesBuffer, unsigned propertyNamesSize)
: JSCell(vm, vm.propertyNameEnumeratorStructure.get())
, m_propertyNames(vm, this, propertyNamesBuffer)
, m_cachedStructureID(vm, this, structure, WriteBarrierStructureID::MayBeNull)
, m_indexedLength(indexedLength)
, m_endStructurePropertyIndex(numberStructureProperties)
, m_endGenericPropertyIndex(propertyNamesSize)
, m_cachedInlineCapacity(structure ? structure->inlineCapacity() : 0)
{
if (m_indexedLength)
m_flags |= JSPropertyNameEnumerator::IndexedMode;
if (m_endStructurePropertyIndex)
m_flags |= JSPropertyNameEnumerator::OwnStructureMode;
if (m_endGenericPropertyIndex - m_endStructurePropertyIndex)
m_flags |= JSPropertyNameEnumerator::GenericMode;
}
void JSPropertyNameEnumerator::finishCreation(VM& vm, RefPtr<PropertyNameArrayData>&& identifiers)
{
Base::finishCreation(vm);
PropertyNameArrayData::PropertyNameVector& vector = identifiers->propertyNameVector();
ASSERT(m_endGenericPropertyIndex == vector.size());
for (unsigned i = 0; i < vector.size(); ++i) {
const Identifier& identifier = vector[i];
m_propertyNames.get()[i].set(vm, this, jsString(vm, identifier.string()));
}
}
template<typename Visitor>
void JSPropertyNameEnumerator::visitChildrenImpl(JSCell* cell, Visitor& visitor)
{
JSPropertyNameEnumerator* thisObject = jsCast<JSPropertyNameEnumerator*>(cell);
ASSERT_GC_OBJECT_INHERITS(thisObject, info());
Base::visitChildren(cell, visitor);
if (auto* propertyNames = thisObject->m_propertyNames.get()) {
visitor.markAuxiliary(propertyNames);
visitor.append(propertyNames, propertyNames + thisObject->sizeOfPropertyNames());
}
visitor.append(thisObject->m_cachedStructureID);
}
DEFINE_VISIT_CHILDREN(JSPropertyNameEnumerator);
// FIXME: Assert that properties returned by getOwnPropertyNames() are reported enumerable by getOwnPropertySlot().
// https://bugs.webkit.org/show_bug.cgi?id=219926
void getEnumerablePropertyNames(JSGlobalObject* globalObject, JSObject* base, PropertyNameArray& propertyNames, uint32_t& indexedLength, uint32_t& structurePropertyCount)
{
VM& vm = globalObject->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
auto getOwnPropertyNames = [&](JSObject* object) {
auto mode = DontEnumPropertiesMode::Exclude;
if (object->type() == ProxyObjectType) {
// This ensures Proxy's [[GetOwnProperty]] trap is invoked only once per property, by OpHasEnumerableProperty.
// Although doing this for all objects is spec-conformant, collecting DontEnum properties isn't free.
mode = DontEnumPropertiesMode::Include;
}
object->methodTable()->getOwnPropertyNames(object, globalObject, propertyNames, mode);
};
Structure* structure = base->structure();
if (structure->canAccessPropertiesQuicklyForEnumeration() && indexedLength == base->getArrayLength()) {
// Inlined JSObject::getOwnNonIndexPropertyNames()
base->methodTable()->getOwnSpecialPropertyNames(base, globalObject, propertyNames, DontEnumPropertiesMode::Exclude);
RETURN_IF_EXCEPTION(scope, void());
base->getNonReifiedStaticPropertyNames(vm, propertyNames, DontEnumPropertiesMode::Exclude);
unsigned nonStructurePropertyCount = propertyNames.size();
structure->getPropertyNamesFromStructure(vm, propertyNames, DontEnumPropertiesMode::Exclude);
scope.assertNoException();
// |propertyNames| contains properties exclusively from the structure.
if (!nonStructurePropertyCount)
structurePropertyCount = propertyNames.size();
} else {
getOwnPropertyNames(base);
RETURN_IF_EXCEPTION(scope, void());
// |propertyNames| contains all indexed properties, so disable enumeration based on getEnumerableLength().
indexedLength = 0;
}
JSObject* object = base;
unsigned prototypeCount = 0;
while (true) {
JSValue prototype = object->getPrototype(vm, globalObject);
RETURN_IF_EXCEPTION(scope, void());
if (prototype.isNull())
break;
if (UNLIKELY(++prototypeCount > JSObject::maximumPrototypeChainDepth)) {
throwStackOverflowError(globalObject, scope);
return;
}
object = asObject(prototype);
getOwnPropertyNames(object);
RETURN_IF_EXCEPTION(scope, void());
}
}
JSString* JSPropertyNameEnumerator::computeNext(JSGlobalObject* globalObject, JSObject* base, uint32_t& index, Flag& mode, bool shouldAllocateIndexedNameString)
{
VM& vm = globalObject->vm();
auto scope = DECLARE_THROW_SCOPE(vm);
ASSERT(indexedLength() || sizeOfPropertyNames());
index++;
switch (mode) {
case InitMode: {
mode = IndexedMode;
index = 0;
FALLTHROUGH;
}
case JSPropertyNameEnumerator::IndexedMode: {
while (index < indexedLength() && !base->hasEnumerableProperty(globalObject, index)) {
RETURN_IF_EXCEPTION(scope, nullptr);
index++;
}
scope.assertNoException();
if (index < indexedLength())
return shouldAllocateIndexedNameString ? jsString(vm, Identifier::from(vm, index).string()) : nullptr;
if (!sizeOfPropertyNames())
return nullptr;
mode = OwnStructureMode;
index = 0;
FALLTHROUGH;
}
case JSPropertyNameEnumerator::OwnStructureMode:
case JSPropertyNameEnumerator::GenericMode: {
JSString* name = nullptr;
while (true) {
if (index >= sizeOfPropertyNames())
break;
name = propertyNameAtIndex(index);
if (!name)
break;
if (index < endStructurePropertyIndex() && base->structureID() == cachedStructureID())
break;
auto id = name->toIdentifier(globalObject);
RETURN_IF_EXCEPTION(scope, nullptr);
if (base->hasEnumerableProperty(globalObject, id))
break;
RETURN_IF_EXCEPTION(scope, nullptr);
name = nullptr;
index++;
}
scope.assertNoException();
if (index >= endStructurePropertyIndex() && index < sizeOfPropertyNames())
mode = GenericMode;
return name;
}
default:
break;
}
RELEASE_ASSERT_NOT_REACHED();
return nullptr;
}
} // namespace JSC