Source/JavaScriptCore/runtime/JSModuleNamespaceObject.cpp - external/github.com/WebKit/webkit - Git at Google

 /*
  * Copyright (C) 2015-2021 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. ``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
  * 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 "JSModuleNamespaceObject.h"

 #include "AbstractModuleRecord.h"
 #include "CyclicModuleRecord.h"
 #include "JSCInlines.h"
 #include "JSModuleEnvironment.h"
 #if ENABLE(WEBASSEMBLY)
 #include "JSWebAssemblyGlobal.h"
 #include "WebAssemblyModuleRecord.h"
 #endif

 namespace JSC {

 const ClassInfo JSModuleNamespaceObject::s_info = { "ModuleNamespaceObject"_s, &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSModuleNamespaceObject) };

 JSModuleNamespaceObject::JSModuleNamespaceObject(VM& vm, Structure* structure, AbstractModuleRecord* moduleRecord, Vector<std::pair<Identifier, AbstractModuleRecord::Resolution>>&& resolutions, bool isDeferred)
     : Base(vm, structure)
     , m_exports()
     , m_moduleRecord(moduleRecord, WriteBarrierEarlyInit)
     , m_isDeferred(isDeferred)
 {
     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects
     // Quoted from the spec:
     //     A List containing the String values of the exported names exposed as own properties of this object.
     //     The list is ordered as if an Array of those String values had been sorted using Array.prototype.sort using SortCompare as comparator.
     //
     // Sort the exported names by the code point order.
     std::ranges::sort(resolutions, WTF::codePointCompareLessThan, [](const auto& resolution) {
         return StringView(resolution.first.impl());
     });

     for (const auto& pair : resolutions) {
         m_exports.add(pair.first.impl(), ExportEntry {
             pair.second.localName,
             WriteBarrier { pair.second.moduleRecord, WriteBarrierEarlyInit },
         });
     }
 }

 void JSModuleNamespaceObject::finishCreation(JSGlobalObject* globalObject)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     Base::finishCreation(vm);
     ASSERT(inherits(info()));
     putDirect(vm, vm.propertyNames->toStringTagSymbol, jsNontrivialString(vm, m_isDeferred ? "Deferred Module"_s : "Module"_s), PropertyAttribute::DontEnum | PropertyAttribute::DontDelete | PropertyAttribute::ReadOnly);

     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-getprototypeof
     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-setprototypeof-v
     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-isextensible
     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-preventextensions
     scope.release();
     methodTable()->preventExtensions(this, globalObject);
 }

 void JSModuleNamespaceObject::destroy(JSCell* cell)
 {
     JSModuleNamespaceObject* thisObject = static_cast<JSModuleNamespaceObject*>(cell);
     thisObject->JSModuleNamespaceObject::~JSModuleNamespaceObject();
 }

 template<typename Visitor>
 void JSModuleNamespaceObject::visitChildrenImpl(JSCell* cell, Visitor& visitor)
 {
     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
     Base::visitChildren(thisObject, visitor);
     visitor.append(thisObject->m_moduleRecord);
     for (auto& entry : thisObject->m_exports.values())
         visitor.appendHidden(entry.moduleRecord);
 }

 DEFINE_VISIT_CHILDREN(JSModuleNamespaceObject);

 // https://tc39.es/proposal-defer-import-eval/#sec-IsSymbolLikeNamespaceKey
 ALWAYS_INLINE bool JSModuleNamespaceObject::isSymbolLikeNamespaceKey(VM& vm, PropertyName propertyName)
 {
     return propertyName.isSymbol() || (m_isDeferred && propertyName == vm.propertyNames->then);
 }

 // https://tc39.es/proposal-defer-import-eval/#sec-GetModuleExportsList
 // The spec returns O.[[Exports]] after triggering evaluation; here we only perform the
 // evaluation side effect since callers already have direct access to m_exports.
 void JSModuleNamespaceObject::ensureDeferredNamespaceEvaluation(JSGlobalObject* globalObject)
 {
     // 1. If O.[[Deferred]] is true, then
     ASSERT(m_isDeferred);
     // Fast path: if the module's cycle has already successfully evaluated, EvaluateModuleSync would
     // observe a fulfilled promise and return without throwing, so we can skip the work entirely.
     // We must consult [[CycleRoot]] here because Evaluate() redirects to it; for a non-root SCC
     // member, status/evaluationError on the module itself may not reflect the cycle's outcome.
     if (auto* cyclic = dynamicDowncast<CyclicModuleRecord>(m_moduleRecord.get())) {
         CyclicModuleRecord* root = cyclic->cycleRoot() ? cyclic->cycleRoot() : cyclic;
         if (root->status() == CyclicModuleRecord::Status::Evaluated && !root->evaluationError())
             return;
     }
     //   1.a. Let m be O.[[Module]].
     //   1.b. Perform ? EvaluateModuleSync(m).
     m_moduleRecord->evaluateSync(globalObject);
     // 2. Return O.[[Exports]].
 }

 static JSValue getValue(JSModuleEnvironment* environment, PropertyName localName, ScopeOffset& scopeOffset)
 {
     SymbolTable* symbolTable = environment->symbolTable();
     {
         ConcurrentJSLocker locker(symbolTable->m_lock);
         auto iter = symbolTable->find(locker, localName.uid());
         ASSERT(iter != symbolTable->end(locker));
         SymbolTableEntry& entry = iter->value;
         ASSERT(!entry.isNull());
         scopeOffset = entry.scopeOffset();
     }
     return environment->variableAt(scopeOffset).get();
 }

 bool JSModuleNamespaceObject::getOwnPropertySlotCommon(JSGlobalObject* globalObject, PropertyName propertyName, PropertySlot& slot)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-getownproperty-p

     // 1. If IsSymbolLikeNamespaceKey(P, O) is true, then return ! Ordinary{Get,GetOwnProperty,HasProperty}(O, P, ...).
     // It may return the descriptor with writable: true, but namespace objects does not allow it in [[Set]] / [[DefineOwnProperty]] side.
     if (isSymbolLikeNamespaceKey(vm, propertyName))
         return Base::getOwnPropertySlot(this, globalObject, propertyName, slot);

     slot.setIsTaintedByOpaqueObject();

     if (m_isDeferred && slot.internalMethodType() != PropertySlot::InternalMethodType::VMInquiry) [[unlikely]] {
         ensureDeferredNamespaceEvaluation(globalObject);
         RETURN_IF_EXCEPTION(scope, false);
     }

     auto iterator = m_exports.find(propertyName.uid());
     if (iterator == m_exports.end())
         return false;
     ExportEntry& exportEntry = iterator->value;

     switch (slot.internalMethodType()) {
     case PropertySlot::InternalMethodType::GetOwnProperty:
     case PropertySlot::InternalMethodType::Get: {
         if (exportEntry.localName == vm.propertyNames->starNamespacePrivateName) {
             // https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-get-p-receiver
             // 10. If binding.[[BindingName]] is "*namespace*", then
             //     a. Return ? GetModuleNamespace(targetModule).
             // We call getModuleNamespace() to ensure materialization. And after that, looking up the value from the scope to encourage module namespace object IC.
             exportEntry.moduleRecord->getModuleNamespace(globalObject);
             RETURN_IF_EXCEPTION(scope, false);
         }
         JSModuleEnvironment* environment = exportEntry.moduleRecord->moduleEnvironment();
         ScopeOffset scopeOffset;
         JSValue value = getValue(environment, exportEntry.localName, scopeOffset);
         // If the value is filled with TDZ value, throw a reference error.
         if (!value) {
             RefPtr uid = propertyName.uid();
             throwVMError(globalObject, scope, createTDZError(globalObject, *uid));
             return false;
         }

 #if ENABLE(WEBASSEMBLY)
         if (is<WebAssemblyModuleRecord>(exportEntry.moduleRecord.get())) {
             if (auto* wasmGlobal = dynamicDowncast<JSWebAssemblyGlobal>(value); wasmGlobal && wasmGlobal->global()->mutability() == Wasm::Mutability::Mutable) {
                 value = wasmGlobal->global()->get(globalObject);
                 RETURN_IF_EXCEPTION(scope, false);
                 slot.setValue(this, static_cast<unsigned>(PropertyAttribute::DontDelete), value);
                 return true;
             }
         }
 #endif

         slot.setValueModuleNamespace(this, static_cast<unsigned>(PropertyAttribute::DontDelete), value, environment, scopeOffset);
         return true;
     }

     case PropertySlot::InternalMethodType::HasProperty: {
         // Do not perform [[Get]] for [[HasProperty]].
         // [[Get]] / [[GetOwnProperty]] onto namespace object could throw an error while [[HasProperty]] just returns true here.
         // https://tc39.github.io/ecma262/#sec-module-namespace-exotic-objects-hasproperty-p
         slot.setValue(this, static_cast<unsigned>(PropertyAttribute::DontDelete), jsUndefined());
         return true;
     }

     case PropertySlot::InternalMethodType::VMInquiry:
         slot.setValue(this, static_cast<unsigned>(JSC::PropertyAttribute::None), jsUndefined());
         return false;
     }

     RELEASE_ASSERT_NOT_REACHED();
     return false;
 }

 bool JSModuleNamespaceObject::getOwnPropertySlot(JSObject* cell, JSGlobalObject* globalObject, PropertyName propertyName, PropertySlot& slot)
 {
     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
     return thisObject->getOwnPropertySlotCommon(globalObject, propertyName, slot);
 }

 bool JSModuleNamespaceObject::getOwnPropertySlotByIndex(JSObject* cell, JSGlobalObject* globalObject, unsigned propertyName, PropertySlot& slot)
 {
     VM& vm = globalObject->vm();
     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
     return thisObject->getOwnPropertySlotCommon(globalObject, Identifier::from(vm, propertyName), slot);
 }

 bool JSModuleNamespaceObject::put(JSCell*, JSGlobalObject* globalObject, PropertyName, JSValue, PutPropertySlot& slot)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     // http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-set-p-v-receiver
     if (slot.isStrictMode())
         throwTypeError(globalObject, scope, ReadonlyPropertyWriteError);
     return false;
 }

 bool JSModuleNamespaceObject::putByIndex(JSCell*, JSGlobalObject* globalObject, unsigned, JSValue, bool shouldThrow)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (shouldThrow)
         throwTypeError(globalObject, scope, ReadonlyPropertyWriteError);
     return false;
 }

 bool JSModuleNamespaceObject::deleteProperty(JSCell* cell, JSGlobalObject* globalObject, PropertyName propertyName, DeletePropertySlot& slot)
 {
     // https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-delete-p
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
     if (thisObject->isSymbolLikeNamespaceKey(vm, propertyName))
         RELEASE_AND_RETURN(scope, Base::deleteProperty(thisObject, globalObject, propertyName, slot));

     if (thisObject->m_isDeferred) [[unlikely]] {
         thisObject->ensureDeferredNamespaceEvaluation(globalObject);
         RETURN_IF_EXCEPTION(scope, false);
     }

     return !thisObject->m_exports.contains(propertyName.uid());
 }

 bool JSModuleNamespaceObject::deletePropertyByIndex(JSCell* cell, JSGlobalObject* globalObject, unsigned propertyName)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
     if (thisObject->m_isDeferred) [[unlikely]] {
         thisObject->ensureDeferredNamespaceEvaluation(globalObject);
         RETURN_IF_EXCEPTION(scope, false);
     }
     return !thisObject->m_exports.contains(Identifier::from(vm, propertyName).impl());
 }

 void JSModuleNamespaceObject::getOwnPropertyNames(JSObject* cell, JSGlobalObject* globalObject, PropertyNameArrayBuilder& propertyNames, DontEnumPropertiesMode mode)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     // https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-ownpropertykeys
     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
     if (thisObject->m_isDeferred) [[unlikely]] {
         thisObject->ensureDeferredNamespaceEvaluation(globalObject);
         RETURN_IF_EXCEPTION(scope, void());
     }
     for (const auto& name : thisObject->m_exports.keys()) {
         if (mode == DontEnumPropertiesMode::Exclude) {
             // Perform [[GetOwnProperty]] to throw ReferenceError if binding is uninitialized.
             PropertySlot slot(cell, PropertySlot::InternalMethodType::GetOwnProperty);
             bool hasProperty = thisObject->getOwnPropertySlotCommon(globalObject, name.get(), slot);
             RETURN_IF_EXCEPTION(scope, void());
             if (!hasProperty)
                 continue;
         }
         propertyNames.add(name);
     }
     if (propertyNames.includeSymbolProperties()) {
         scope.release();
         thisObject->getOwnNonIndexPropertyNames(globalObject, propertyNames, mode);
     }
 }

 bool JSModuleNamespaceObject::defineOwnProperty(JSObject* cell, JSGlobalObject* globalObject, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     // https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-defineownproperty-p-desc

     JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);

     // 1. If IsSymbolLikeNamespaceKey(P, O) is true, return ! OrdinaryDefineOwnProperty(O, P, Desc).
     if (thisObject->isSymbolLikeNamespaceKey(vm, propertyName))
         RELEASE_AND_RETURN(scope, Base::defineOwnProperty(thisObject, globalObject, propertyName, descriptor, shouldThrow));

     // 2. Let current be ? O.[[GetOwnProperty]](P).
     PropertyDescriptor current;
     bool isCurrentDefined = thisObject->getOwnPropertyDescriptor(globalObject, propertyName, current);
     RETURN_IF_EXCEPTION(scope, false);

     // 3. If current is undefined, return false.
     if (!isCurrentDefined) {
         if (shouldThrow)
             throwTypeError(globalObject, scope, NonExtensibleObjectPropertyDefineError);
         return false;
     }

     // 4. If IsAccessorDescriptor(Desc) is true, return false.
     if (descriptor.isAccessorDescriptor()) {
         if (shouldThrow)
             throwTypeError(globalObject, scope, "Cannot change module namespace object's binding to accessor"_s);
         return false;
     }

     // 5. If Desc.[[Writable]] is present and has value false, return false.
     if (descriptor.writablePresent() && !descriptor.writable()) {
         if (shouldThrow)
             throwTypeError(globalObject, scope, "Cannot change module namespace object's binding to non-writable attribute"_s);
         return false;
     }

     // 6. If Desc.[[Enumerable]] is present and has value false, return false.
     if (descriptor.enumerablePresent() && !descriptor.enumerable()) {
         if (shouldThrow)
             throwTypeError(globalObject, scope, "Cannot replace module namespace object's binding with non-enumerable attribute"_s);
         return false;
     }

     // 7. If Desc.[[Configurable]] is present and has value true, return false.
     if (descriptor.configurablePresent() && descriptor.configurable()) {
         if (shouldThrow)
             throwTypeError(globalObject, scope, "Cannot replace module namespace object's binding with configurable attribute"_s);
         return false;
     }

     // 8. If Desc.[[Value]] is present, return SameValue(Desc.[[Value]], current.[[Value]]).
     if (descriptor.value()) {
         bool result = sameValue(globalObject, descriptor.value(), current.value());
         RETURN_IF_EXCEPTION(scope, false);
         if (!result) {
             if (shouldThrow)
                 throwTypeError(globalObject, scope, "Cannot replace module namespace object's binding's value"_s);
             return false;
         }
     }

     // 9. Return true.
     return true;
 }

 } // namespace JSC
	/*
	* Copyright (C) 2015-2021 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. ``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
	* 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 "JSModuleNamespaceObject.h"

	#include "AbstractModuleRecord.h"
	#include "CyclicModuleRecord.h"
	#include "JSCInlines.h"
	#include "JSModuleEnvironment.h"
	#if ENABLE(WEBASSEMBLY)
	#include "JSWebAssemblyGlobal.h"
	#include "WebAssemblyModuleRecord.h"
	#endif

	namespace JSC {

	const ClassInfo JSModuleNamespaceObject::s_info = { "ModuleNamespaceObject"_s, &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSModuleNamespaceObject) };

	JSModuleNamespaceObject::JSModuleNamespaceObject(VM& vm, Structure* structure, AbstractModuleRecord* moduleRecord, Vector<std::pair<Identifier, AbstractModuleRecord::Resolution>>&& resolutions, bool isDeferred)
	: Base(vm, structure)
	, m_exports()
	, m_moduleRecord(moduleRecord, WriteBarrierEarlyInit)
	, m_isDeferred(isDeferred)
	{
	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects
	// Quoted from the spec:
	// A List containing the String values of the exported names exposed as own properties of this object.
	// The list is ordered as if an Array of those String values had been sorted using Array.prototype.sort using SortCompare as comparator.
	//
	// Sort the exported names by the code point order.
	std::ranges::sort(resolutions, WTF::codePointCompareLessThan, [](const auto& resolution) {
	return StringView(resolution.first.impl());
	});

	for (const auto& pair : resolutions) {
	m_exports.add(pair.first.impl(), ExportEntry {
	pair.second.localName,
	WriteBarrier { pair.second.moduleRecord, WriteBarrierEarlyInit },
	});
	}
	}

	void JSModuleNamespaceObject::finishCreation(JSGlobalObject* globalObject)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	Base::finishCreation(vm);
	ASSERT(inherits(info()));
	putDirect(vm, vm.propertyNames->toStringTagSymbol, jsNontrivialString(vm, m_isDeferred ? "Deferred Module"_s : "Module"_s), PropertyAttribute::DontEnum \| PropertyAttribute::DontDelete \| PropertyAttribute::ReadOnly);

	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-getprototypeof
	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-setprototypeof-v
	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-isextensible
	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-preventextensions
	scope.release();
	methodTable()->preventExtensions(this, globalObject);
	}

	void JSModuleNamespaceObject::destroy(JSCell* cell)
	{
	JSModuleNamespaceObject* thisObject = static_cast<JSModuleNamespaceObject*>(cell);
	thisObject->JSModuleNamespaceObject::~JSModuleNamespaceObject();
	}

	template<typename Visitor>
	void JSModuleNamespaceObject::visitChildrenImpl(JSCell* cell, Visitor& visitor)
	{
	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
	ASSERT_GC_OBJECT_INHERITS(thisObject, info());
	Base::visitChildren(thisObject, visitor);
	visitor.append(thisObject->m_moduleRecord);
	for (auto& entry : thisObject->m_exports.values())
	visitor.appendHidden(entry.moduleRecord);
	}

	DEFINE_VISIT_CHILDREN(JSModuleNamespaceObject);

	// https://tc39.es/proposal-defer-import-eval/#sec-IsSymbolLikeNamespaceKey
	ALWAYS_INLINE bool JSModuleNamespaceObject::isSymbolLikeNamespaceKey(VM& vm, PropertyName propertyName)
	{
	return propertyName.isSymbol() \|\| (m_isDeferred && propertyName == vm.propertyNames->then);
	}

	// https://tc39.es/proposal-defer-import-eval/#sec-GetModuleExportsList
	// The spec returns O.[[Exports]] after triggering evaluation; here we only perform the
	// evaluation side effect since callers already have direct access to m_exports.
	void JSModuleNamespaceObject::ensureDeferredNamespaceEvaluation(JSGlobalObject* globalObject)
	{
	// 1. If O.[[Deferred]] is true, then
	ASSERT(m_isDeferred);
	// Fast path: if the module's cycle has already successfully evaluated, EvaluateModuleSync would
	// observe a fulfilled promise and return without throwing, so we can skip the work entirely.
	// We must consult [[CycleRoot]] here because Evaluate() redirects to it; for a non-root SCC
	// member, status/evaluationError on the module itself may not reflect the cycle's outcome.
	if (auto* cyclic = dynamicDowncast<CyclicModuleRecord>(m_moduleRecord.get())) {
	CyclicModuleRecord* root = cyclic->cycleRoot() ? cyclic->cycleRoot() : cyclic;
	if (root->status() == CyclicModuleRecord::Status::Evaluated && !root->evaluationError())
	return;
	}
	// 1.a. Let m be O.[[Module]].
	// 1.b. Perform ? EvaluateModuleSync(m).
	m_moduleRecord->evaluateSync(globalObject);
	// 2. Return O.[[Exports]].
	}

	static JSValue getValue(JSModuleEnvironment* environment, PropertyName localName, ScopeOffset& scopeOffset)
	{
	SymbolTable* symbolTable = environment->symbolTable();
	{
	ConcurrentJSLocker locker(symbolTable->m_lock);
	auto iter = symbolTable->find(locker, localName.uid());
	ASSERT(iter != symbolTable->end(locker));
	SymbolTableEntry& entry = iter->value;
	ASSERT(!entry.isNull());
	scopeOffset = entry.scopeOffset();
	}
	return environment->variableAt(scopeOffset).get();
	}

	bool JSModuleNamespaceObject::getOwnPropertySlotCommon(JSGlobalObject* globalObject, PropertyName propertyName, PropertySlot& slot)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-getownproperty-p

	// 1. If IsSymbolLikeNamespaceKey(P, O) is true, then return ! Ordinary{Get,GetOwnProperty,HasProperty}(O, P, ...).
	// It may return the descriptor with writable: true, but namespace objects does not allow it in [[Set]] / [[DefineOwnProperty]] side.
	if (isSymbolLikeNamespaceKey(vm, propertyName))
	return Base::getOwnPropertySlot(this, globalObject, propertyName, slot);

	slot.setIsTaintedByOpaqueObject();

	if (m_isDeferred && slot.internalMethodType() != PropertySlot::InternalMethodType::VMInquiry) [[unlikely]] {
	ensureDeferredNamespaceEvaluation(globalObject);
	RETURN_IF_EXCEPTION(scope, false);
	}

	auto iterator = m_exports.find(propertyName.uid());
	if (iterator == m_exports.end())
	return false;
	ExportEntry& exportEntry = iterator->value;

	switch (slot.internalMethodType()) {
	case PropertySlot::InternalMethodType::GetOwnProperty:
	case PropertySlot::InternalMethodType::Get: {
	if (exportEntry.localName == vm.propertyNames->starNamespacePrivateName) {
	// https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-get-p-receiver
	// 10. If binding.[[BindingName]] is "namespace", then
	// a. Return ? GetModuleNamespace(targetModule).
	// We call getModuleNamespace() to ensure materialization. And after that, looking up the value from the scope to encourage module namespace object IC.
	exportEntry.moduleRecord->getModuleNamespace(globalObject);
	RETURN_IF_EXCEPTION(scope, false);
	}
	JSModuleEnvironment* environment = exportEntry.moduleRecord->moduleEnvironment();
	ScopeOffset scopeOffset;
	JSValue value = getValue(environment, exportEntry.localName, scopeOffset);
	// If the value is filled with TDZ value, throw a reference error.
	if (!value) {
	RefPtr uid = propertyName.uid();
	throwVMError(globalObject, scope, createTDZError(globalObject, *uid));
	return false;
	}

	#if ENABLE(WEBASSEMBLY)
	if (is<WebAssemblyModuleRecord>(exportEntry.moduleRecord.get())) {
	if (auto* wasmGlobal = dynamicDowncast<JSWebAssemblyGlobal>(value); wasmGlobal && wasmGlobal->global()->mutability() == Wasm::Mutability::Mutable) {
	value = wasmGlobal->global()->get(globalObject);
	RETURN_IF_EXCEPTION(scope, false);
	slot.setValue(this, static_cast<unsigned>(PropertyAttribute::DontDelete), value);
	return true;
	}
	}
	#endif

	slot.setValueModuleNamespace(this, static_cast<unsigned>(PropertyAttribute::DontDelete), value, environment, scopeOffset);
	return true;
	}

	case PropertySlot::InternalMethodType::HasProperty: {
	// Do not perform [[Get]] for [[HasProperty]].
	// [[Get]] / [[GetOwnProperty]] onto namespace object could throw an error while [[HasProperty]] just returns true here.
	// https://tc39.github.io/ecma262/#sec-module-namespace-exotic-objects-hasproperty-p
	slot.setValue(this, static_cast<unsigned>(PropertyAttribute::DontDelete), jsUndefined());
	return true;
	}

	case PropertySlot::InternalMethodType::VMInquiry:
	slot.setValue(this, static_cast<unsigned>(JSC::PropertyAttribute::None), jsUndefined());
	return false;
	}

	RELEASE_ASSERT_NOT_REACHED();
	return false;
	}

	bool JSModuleNamespaceObject::getOwnPropertySlot(JSObject* cell, JSGlobalObject* globalObject, PropertyName propertyName, PropertySlot& slot)
	{
	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
	return thisObject->getOwnPropertySlotCommon(globalObject, propertyName, slot);
	}

	bool JSModuleNamespaceObject::getOwnPropertySlotByIndex(JSObject* cell, JSGlobalObject* globalObject, unsigned propertyName, PropertySlot& slot)
	{
	VM& vm = globalObject->vm();
	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
	return thisObject->getOwnPropertySlotCommon(globalObject, Identifier::from(vm, propertyName), slot);
	}

	bool JSModuleNamespaceObject::put(JSCell, JSGlobalObject globalObject, PropertyName, JSValue, PutPropertySlot& slot)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	// http://www.ecma-international.org/ecma-262/6.0/#sec-module-namespace-exotic-objects-set-p-v-receiver
	if (slot.isStrictMode())
	throwTypeError(globalObject, scope, ReadonlyPropertyWriteError);
	return false;
	}

	bool JSModuleNamespaceObject::putByIndex(JSCell, JSGlobalObject globalObject, unsigned, JSValue, bool shouldThrow)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (shouldThrow)
	throwTypeError(globalObject, scope, ReadonlyPropertyWriteError);
	return false;
	}

	bool JSModuleNamespaceObject::deleteProperty(JSCell* cell, JSGlobalObject* globalObject, PropertyName propertyName, DeletePropertySlot& slot)
	{
	// https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-delete-p
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
	if (thisObject->isSymbolLikeNamespaceKey(vm, propertyName))
	RELEASE_AND_RETURN(scope, Base::deleteProperty(thisObject, globalObject, propertyName, slot));

	if (thisObject->m_isDeferred) [[unlikely]] {
	thisObject->ensureDeferredNamespaceEvaluation(globalObject);
	RETURN_IF_EXCEPTION(scope, false);
	}

	return !thisObject->m_exports.contains(propertyName.uid());
	}

	bool JSModuleNamespaceObject::deletePropertyByIndex(JSCell* cell, JSGlobalObject* globalObject, unsigned propertyName)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
	if (thisObject->m_isDeferred) [[unlikely]] {
	thisObject->ensureDeferredNamespaceEvaluation(globalObject);
	RETURN_IF_EXCEPTION(scope, false);
	}
	return !thisObject->m_exports.contains(Identifier::from(vm, propertyName).impl());
	}

	void JSModuleNamespaceObject::getOwnPropertyNames(JSObject* cell, JSGlobalObject* globalObject, PropertyNameArrayBuilder& propertyNames, DontEnumPropertiesMode mode)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	// https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-ownpropertykeys
	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);
	if (thisObject->m_isDeferred) [[unlikely]] {
	thisObject->ensureDeferredNamespaceEvaluation(globalObject);
	RETURN_IF_EXCEPTION(scope, void());
	}
	for (const auto& name : thisObject->m_exports.keys()) {
	if (mode == DontEnumPropertiesMode::Exclude) {
	// Perform [[GetOwnProperty]] to throw ReferenceError if binding is uninitialized.
	PropertySlot slot(cell, PropertySlot::InternalMethodType::GetOwnProperty);
	bool hasProperty = thisObject->getOwnPropertySlotCommon(globalObject, name.get(), slot);
	RETURN_IF_EXCEPTION(scope, void());
	if (!hasProperty)
	continue;
	}
	propertyNames.add(name);
	}
	if (propertyNames.includeSymbolProperties()) {
	scope.release();
	thisObject->getOwnNonIndexPropertyNames(globalObject, propertyNames, mode);
	}
	}

	bool JSModuleNamespaceObject::defineOwnProperty(JSObject* cell, JSGlobalObject* globalObject, PropertyName propertyName, const PropertyDescriptor& descriptor, bool shouldThrow)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	// https://tc39.es/ecma262/#sec-module-namespace-exotic-objects-defineownproperty-p-desc

	JSModuleNamespaceObject* thisObject = uncheckedDowncast<JSModuleNamespaceObject>(cell);

	// 1. If IsSymbolLikeNamespaceKey(P, O) is true, return ! OrdinaryDefineOwnProperty(O, P, Desc).
	if (thisObject->isSymbolLikeNamespaceKey(vm, propertyName))
	RELEASE_AND_RETURN(scope, Base::defineOwnProperty(thisObject, globalObject, propertyName, descriptor, shouldThrow));

	// 2. Let current be ? O.[[GetOwnProperty]](P).
	PropertyDescriptor current;
	bool isCurrentDefined = thisObject->getOwnPropertyDescriptor(globalObject, propertyName, current);
	RETURN_IF_EXCEPTION(scope, false);

	// 3. If current is undefined, return false.
	if (!isCurrentDefined) {
	if (shouldThrow)
	throwTypeError(globalObject, scope, NonExtensibleObjectPropertyDefineError);
	return false;
	}

	// 4. If IsAccessorDescriptor(Desc) is true, return false.
	if (descriptor.isAccessorDescriptor()) {
	if (shouldThrow)
	throwTypeError(globalObject, scope, "Cannot change module namespace object's binding to accessor"_s);
	return false;
	}

	// 5. If Desc.[[Writable]] is present and has value false, return false.
	if (descriptor.writablePresent() && !descriptor.writable()) {
	if (shouldThrow)
	throwTypeError(globalObject, scope, "Cannot change module namespace object's binding to non-writable attribute"_s);
	return false;
	}

	// 6. If Desc.[[Enumerable]] is present and has value false, return false.
	if (descriptor.enumerablePresent() && !descriptor.enumerable()) {
	if (shouldThrow)
	throwTypeError(globalObject, scope, "Cannot replace module namespace object's binding with non-enumerable attribute"_s);
	return false;
	}

	// 7. If Desc.[[Configurable]] is present and has value true, return false.
	if (descriptor.configurablePresent() && descriptor.configurable()) {
	if (shouldThrow)
	throwTypeError(globalObject, scope, "Cannot replace module namespace object's binding with configurable attribute"_s);
	return false;
	}

	// 8. If Desc.[[Value]] is present, return SameValue(Desc.[[Value]], current.[[Value]]).
	if (descriptor.value()) {
	bool result = sameValue(globalObject, descriptor.value(), current.value());
	RETURN_IF_EXCEPTION(scope, false);
	if (!result) {
	if (shouldThrow)
	throwTypeError(globalObject, scope, "Cannot replace module namespace object's binding's value"_s);
	return false;
	}
	}

	// 9. Return true.
	return true;
	}

	} // namespace JSC