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/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Runtime/ArgumentsObject.h>
#include <LibJS/Runtime/Completion.h>
#include <LibJS/Runtime/GlobalObject.h>
namespace JS {
ArgumentsObject::ArgumentsObject(Realm& realm, Environment& environment)
: Object(*realm.global_object().object_prototype())
, m_environment(environment)
{
}
void ArgumentsObject::initialize(GlobalObject& global_object)
{
Base::initialize(global_object);
set_has_parameter_map();
m_parameter_map = Object::create(global_object, nullptr);
}
void ArgumentsObject::visit_edges(Cell::Visitor& visitor)
{
Base::visit_edges(visitor);
visitor.visit(&m_environment);
visitor.visit(m_parameter_map);
}
// 10.4.4.3 [[Get]] ( P, Receiver ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-get-p-receiver
ThrowCompletionOr<Value> ArgumentsObject::internal_get(PropertyKey const& property_key, Value receiver) const
{
// 1. Let map be args.[[ParameterMap]].
auto& map = *m_parameter_map;
// 2. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(m_parameter_map->has_own_property(property_key));
// 3. If isMapped is false, then
if (!is_mapped) {
// a. Return ? OrdinaryGet(args, P, Receiver).
return Object::internal_get(property_key, receiver);
}
// FIXME: a. Assert: map contains a formal parameter mapping for P.
// b. Return ! Get(map, P).
return MUST(map.get(property_key));
}
// 10.4.4.4 [[Set]] ( P, V, Receiver ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-set-p-v-receiver
ThrowCompletionOr<bool> ArgumentsObject::internal_set(PropertyKey const& property_key, Value value, Value receiver)
{
bool is_mapped = false;
// 1. If SameValue(args, Receiver) is false, then
if (!same_value(this, receiver)) {
// a. Let isMapped be false.
is_mapped = false;
} else {
// a. Let map be args.[[ParameterMap]].
// b. Let isMapped be ! HasOwnProperty(map, P).
is_mapped = MUST(parameter_map().has_own_property(property_key));
}
// 3. If isMapped is true, then
if (is_mapped) {
// a. Assert: The following Set will succeed, since formal parameters mapped by arguments objects are always writable.
// b. Perform ! Set(map, P, V, false).
MUST(m_parameter_map->set(property_key, value, Object::ShouldThrowExceptions::No));
}
// 4. Return ? OrdinarySet(args, P, V, Receiver).
return Object::internal_set(property_key, value, receiver);
}
// 10.4.4.5 [[Delete]] ( P ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-delete-p
ThrowCompletionOr<bool> ArgumentsObject::internal_delete(PropertyKey const& property_key)
{
// 1. Let map be args.[[ParameterMap]].
auto& map = parameter_map();
// 2. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(map.has_own_property(property_key));
// 3. Let result be ? OrdinaryDelete(args, P).
bool result = TRY(Object::internal_delete(property_key));
// 4. If result is true and isMapped is true, then
if (result && is_mapped) {
// a. Perform ! map.[[Delete]](P).
MUST(map.internal_delete(property_key));
}
// 5. Return result.
return result;
}
// 10.4.4.1 [[GetOwnProperty]] ( P ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-getownproperty-p
ThrowCompletionOr<Optional<PropertyDescriptor>> ArgumentsObject::internal_get_own_property(PropertyKey const& property_key) const
{
// 1. Let desc be OrdinaryGetOwnProperty(args, P).
auto desc = MUST(Object::internal_get_own_property(property_key));
// 2. If desc is undefined, return desc.
if (!desc.has_value())
return desc;
// 3. Let map be args.[[ParameterMap]].
// 4. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(m_parameter_map->has_own_property(property_key));
// 5. If isMapped is true, then
if (is_mapped) {
// a. Set desc.[[Value]] to ! Get(map, P).
desc->value = MUST(m_parameter_map->get(property_key));
}
// 6. Return desc.
return desc;
}
// 10.4.4.2 [[DefineOwnProperty]] ( P, Desc ), https://tc39.es/ecma262/#sec-arguments-exotic-objects-defineownproperty-p-desc
ThrowCompletionOr<bool> ArgumentsObject::internal_define_own_property(PropertyKey const& property_key, PropertyDescriptor const& descriptor)
{
// 1. Let map be args.[[ParameterMap]].
auto& map = parameter_map();
// 2. Let isMapped be ! HasOwnProperty(map, P).
bool is_mapped = MUST(map.has_own_property(property_key));
// 3. Let newArgDesc be Desc.
auto new_arg_desc = descriptor;
// 4. If isMapped is true and IsDataDescriptor(Desc) is true, then
if (is_mapped && descriptor.is_data_descriptor()) {
// a. If Desc does not have a [[Value]] field and Desc has a [[Writable]] field, and Desc.[[Writable]] is false, then
if (!descriptor.value.has_value() && descriptor.writable.has_value() && descriptor.writable == false) {
// i. Set newArgDesc to a copy of Desc.
new_arg_desc = descriptor;
// ii. Set newArgDesc.[[Value]] to ! Get(map, P).
new_arg_desc.value = MUST(map.get(property_key));
}
}
// 5. Let allowed be ! OrdinaryDefineOwnProperty(args, P, newArgDesc).
bool allowed = MUST(Object::internal_define_own_property(property_key, new_arg_desc));
// 6. If allowed is false, return false.
if (!allowed)
return false;
// 7. If isMapped is true, then
if (is_mapped) {
// a. If IsAccessorDescriptor(Desc) is true, then
if (descriptor.is_accessor_descriptor()) {
// i. Perform ! map.[[Delete]](P).
MUST(map.internal_delete(property_key));
} else {
// i. If Desc has a [[Value]] field, then
if (descriptor.value.has_value()) {
// 1. Assert: The following Set will succeed, since formal parameters mapped by arguments objects are always writable.
// 2. Perform ! Set(map, P, Desc.[[Value]], false).
MUST(map.set(property_key, descriptor.value.value(), Object::ShouldThrowExceptions::No));
}
// ii. If Desc has a [[Writable]] field and Desc.[[Writable]] is false, then
if (descriptor.writable == false) {
// 1. Perform ! map.[[Delete]](P).
MUST(map.internal_delete(property_key));
}
}
}
// 8. Return true.
return true;
}
}
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