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ladybird/Userland/Libraries/LibJS/Runtime/Object.cpp
Linus Groh 7327a28ccc LibJS: Add ECMA-262 section/title/URL comments almost everywhere 
As mentioned on Discord earlier, we'll add these to all new functions
going forward - this is the backfill. Reasons:

- It makes you look at the spec, implementing based on MDN or V8
  behavior is a no-go
- It makes finding the various functions that are non-compliant easier,
  in the future everything should either have such a comment or, if it's
  not from the spec at all, a comment explaining why that is the case
- It makes it easier to check whether a certain abstract operation is
  implemented in LibJS, not all of them use the same name as the spec.
  E.g. RejectPromise() is Promise::reject()
- It makes it easier to reason about vm.arguments(), e.g. when the
  function has a rest parameter
- It makes it easier to see whether a certain function is from a
  proposal or Annex B

Also:

- Add arguments to all functions and abstract operations that already
  had a comment
- Fix some outdated section numbers
- Replace some ecma-international.org URLs with tc39.es
2021-06-13 00:33:28 +01:00

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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <AK/String.h>
#include <AK/TemporaryChange.h>
#include <LibJS/Heap/Heap.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/Accessor.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/NativeProperty.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/ProxyObject.h>
#include <LibJS/Runtime/Shape.h>
#include <LibJS/Runtime/StringObject.h>
#include <LibJS/Runtime/TemporaryClearException.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
PropertyDescriptor PropertyDescriptor::from_dictionary(VM& vm, const Object& object)
{
PropertyAttributes attributes;
if (object.has_property(vm.names.configurable)) {
attributes.set_has_configurable();
if (object.get(vm.names.configurable).value_or(Value(false)).to_boolean())
attributes.set_configurable();
if (vm.exception())
return {};
}
if (object.has_property(vm.names.enumerable)) {
attributes.set_has_enumerable();
if (object.get(vm.names.enumerable).value_or(Value(false)).to_boolean())
attributes.set_enumerable();
if (vm.exception())
return {};
}
if (object.has_property(vm.names.writable)) {
attributes.set_has_writable();
if (object.get(vm.names.writable).value_or(Value(false)).to_boolean())
attributes.set_writable();
if (vm.exception())
return {};
}
PropertyDescriptor descriptor { attributes, object.get(vm.names.value), nullptr, nullptr };
if (vm.exception())
return {};
auto getter = object.get(vm.names.get);
if (vm.exception())
return {};
if (getter.is_function())
descriptor.getter = &getter.as_function();
auto setter = object.get(vm.names.set);
if (vm.exception())
return {};
if (setter.is_function())
descriptor.setter = &setter.as_function();
return descriptor;
}
Object* Object::create_empty(GlobalObject& global_object)
{
return global_object.heap().allocate<Object>(global_object, *global_object.new_object_shape());
}
Object::Object(GlobalObjectTag)
{
// This is the global object
m_shape = heap().allocate_without_global_object<Shape>(*this);
}
Object::Object(ConstructWithoutPrototypeTag, GlobalObject& global_object)
{
m_shape = heap().allocate_without_global_object<Shape>(global_object);
}
Object::Object(Object& prototype)
{
m_shape = prototype.global_object().empty_object_shape();
set_prototype(&prototype);
}
Object::Object(Shape& shape)
: m_shape(&shape)
{
m_storage.resize(shape.property_count());
}
void Object::initialize(GlobalObject&)
{
}
Object::~Object()
{
}
Object* Object::prototype()
{
return shape().prototype();
}
const Object* Object::prototype() const
{
return shape().prototype();
}
// 10.1.2.1 OrdinarySetPrototypeOf ( O, V ), https://tc39.es/ecma262/#sec-ordinarysetprototypeof
bool Object::set_prototype(Object* new_prototype)
{
if (prototype() == new_prototype)
return true;
if (!m_is_extensible)
return false;
auto* prototype = new_prototype;
while (prototype) {
if (prototype == this)
return false;
// NOTE: This is a best-effort implementation of the following step:
// "If p.[[GetPrototypeOf]] is not the ordinary object internal method defined in 10.1.1,
// set done to true."
// We don't have a good way of detecting whether certain virtual Object methods have been
// overridden by a given object, but as ProxyObject is the only one doing that, this check
// does the trick.
if (is<ProxyObject>(prototype))
break;
prototype = prototype->prototype();
}
auto& shape = this->shape();
if (shape.is_unique())
shape.set_prototype_without_transition(new_prototype);
else
m_shape = shape.create_prototype_transition(new_prototype);
return true;
}
bool Object::has_prototype(const Object* prototype) const
{
for (auto* object = this->prototype(); object; object = object->prototype()) {
if (vm().exception())
return false;
if (object == prototype)
return true;
}
return false;
}
bool Object::prevent_extensions()
{
m_is_extensible = false;
return true;
}
// 7.3.15 SetIntegrityLevel ( O, level ), https://tc39.es/ecma262/#sec-setintegritylevel
bool Object::set_integrity_level(IntegrityLevel level)
{
// FIXME: This feels clunky and should get nicer abstractions.
auto update_property = [this](auto& property_name, auto new_attributes) {
if (property_name.is_number()) {
auto value_and_attributes = m_indexed_properties.get(nullptr, property_name.as_number(), false).value();
auto value = value_and_attributes.value;
auto attributes = value_and_attributes.attributes.bits() & new_attributes;
m_indexed_properties.put(nullptr, property_name.as_number(), value, attributes, false);
} else {
auto metadata = shape().lookup(property_name.to_string_or_symbol()).value();
auto attributes = metadata.attributes.bits() & new_attributes;
if (m_shape->is_unique())
m_shape->reconfigure_property_in_unique_shape(property_name.to_string_or_symbol(), attributes);
else
set_shape(*m_shape->create_configure_transition(property_name.to_string_or_symbol(), attributes));
}
};
auto& vm = this->vm();
auto status = prevent_extensions();
if (vm.exception())
return false;
if (!status)
return false;
auto keys = get_own_properties(PropertyKind::Key);
if (vm.exception())
return false;
switch (level) {
case IntegrityLevel::Sealed:
for (auto& key : keys) {
auto property_name = PropertyName::from_value(global_object(), key);
if (property_name.is_string()) {
i32 property_index = property_name.as_string().to_int().value_or(-1);
if (property_index >= 0)
property_name = property_index;
}
update_property(property_name, ~Attribute::Configurable);
if (vm.exception())
return {};
}
break;
case IntegrityLevel::Frozen:
for (auto& key : keys) {
auto property_name = PropertyName::from_value(global_object(), key);
if (property_name.is_string()) {
i32 property_index = property_name.as_string().to_int().value_or(-1);
if (property_index >= 0)
property_name = property_index;
}
auto property_descriptor = get_own_property_descriptor(property_name);
if (!property_descriptor.has_value())
continue;
u8 attributes = property_descriptor->is_accessor_descriptor()
? ~Attribute::Configurable
: ~Attribute::Configurable & ~Attribute::Writable;
update_property(property_name, attributes);
if (vm.exception())
return {};
}
break;
default:
VERIFY_NOT_REACHED();
}
return true;
}
// 7.3.16 TestIntegrityLevel ( O, level ), https://tc39.es/ecma262/#sec-testintegritylevel
bool Object::test_integrity_level(IntegrityLevel level)
{
auto& vm = this->vm();
auto extensible = is_extensible();
if (vm.exception())
return false;
if (extensible)
return false;
auto keys = get_own_properties(PropertyKind::Key);
if (vm.exception())
return false;
for (auto& key : keys) {
auto property_name = PropertyName::from_value(global_object(), key);
auto property_descriptor = get_own_property_descriptor(property_name);
if (!property_descriptor.has_value())
continue;
if (property_descriptor->attributes.is_configurable())
return false;
if (level == IntegrityLevel::Frozen && property_descriptor->is_data_descriptor()) {
if (property_descriptor->attributes.is_writable())
return false;
}
}
return true;
}
Value Object::get_own_property(const PropertyName& property_name, Value receiver, bool without_side_effects) const
{
VERIFY(property_name.is_valid());
VERIFY(!receiver.is_empty());
Value value_here;
if (property_name.is_number()) {
auto existing_property = m_indexed_properties.get(nullptr, property_name.as_number(), false);
if (!existing_property.has_value())
return {};
value_here = existing_property.value().value.value_or(js_undefined());
} else {
auto metadata = shape().lookup(property_name.to_string_or_symbol());
if (!metadata.has_value())
return {};
value_here = m_storage[metadata.value().offset].value_or(js_undefined());
}
VERIFY(!value_here.is_empty());
if (!without_side_effects) {
if (value_here.is_accessor())
return value_here.as_accessor().call_getter(receiver);
if (value_here.is_native_property())
return call_native_property_getter(value_here.as_native_property(), receiver);
}
return value_here;
}
MarkedValueList Object::get_own_properties(PropertyKind kind, bool only_enumerable_properties, GetOwnPropertyReturnType return_type) const
{
MarkedValueList properties(heap());
// FIXME: Support generic iterables
if (is<StringObject>(*this)) {
auto str = static_cast<const StringObject&>(*this).primitive_string().string();
for (size_t i = 0; i < str.length(); ++i) {
if (kind == PropertyKind::Key) {
properties.append(js_string(vm(), String::number(i)));
} else if (kind == PropertyKind::Value) {
properties.append(js_string(vm(), String::formatted("{:c}", str[i])));
} else {
auto* entry_array = Array::create(global_object());
entry_array->define_property(0, js_string(vm(), String::number(i)));
entry_array->define_property(1, js_string(vm(), String::formatted("{:c}", str[i])));
properties.append(entry_array);
}
if (vm().exception())
return MarkedValueList { heap() };
}
return properties;
}
if (return_type != GetOwnPropertyReturnType::SymbolOnly) {
for (auto& entry : m_indexed_properties) {
auto value_and_attributes = entry.value_and_attributes(const_cast<Object*>(this));
if (only_enumerable_properties && !value_and_attributes.attributes.is_enumerable())
continue;
if (kind == PropertyKind::Key) {
properties.append(js_string(vm(), String::number(entry.index())));
} else if (kind == PropertyKind::Value) {
properties.append(value_and_attributes.value);
} else {
auto* entry_array = Array::create(global_object());
entry_array->define_property(0, js_string(vm(), String::number(entry.index())));
entry_array->define_property(1, value_and_attributes.value);
properties.append(entry_array);
}
if (vm().exception())
return MarkedValueList { heap() };
}
}
auto add_property_to_results = [&](auto& property) {
if (kind == PropertyKind::Key) {
properties.append(property.key.to_value(vm()));
} else if (kind == PropertyKind::Value) {
properties.append(get(property.key));
} else {
auto* entry_array = Array::create(global_object());
entry_array->define_property(0, property.key.to_value(vm()));
entry_array->define_property(1, get(property.key));
properties.append(entry_array);
}
};
// NOTE: Most things including for..in/of and Object.{keys,values,entries}() use StringOnly, and in those
// cases we won't be iterating the ordered property table twice. We can certainly improve this though.
if (return_type == GetOwnPropertyReturnType::All || return_type == GetOwnPropertyReturnType::StringOnly) {
for (auto& it : shape().property_table_ordered()) {
if (only_enumerable_properties && !it.value.attributes.is_enumerable())
continue;
if (it.key.is_symbol())
continue;
add_property_to_results(it);
if (vm().exception())
return MarkedValueList { heap() };
}
}
if (return_type == GetOwnPropertyReturnType::All || return_type == GetOwnPropertyReturnType::SymbolOnly) {
for (auto& it : shape().property_table_ordered()) {
if (only_enumerable_properties && !it.value.attributes.is_enumerable())
continue;
if (it.key.is_string())
continue;
add_property_to_results(it);
if (vm().exception())
return MarkedValueList { heap() };
}
}
return properties;
}
// 7.3.23 EnumerableOwnPropertyNames ( O, kind ), https://tc39.es/ecma262/#sec-enumerableownpropertynames
MarkedValueList Object::get_enumerable_own_property_names(PropertyKind kind) const
{
return get_own_properties(kind, true, Object::GetOwnPropertyReturnType::StringOnly);
}
Optional<PropertyDescriptor> Object::get_own_property_descriptor(const PropertyName& property_name) const
{
VERIFY(property_name.is_valid());
Value value;
PropertyAttributes attributes;
if (property_name.is_number()) {
auto existing_value = m_indexed_properties.get(nullptr, property_name.as_number(), false);
if (!existing_value.has_value())
return {};
value = existing_value.value().value;
attributes = existing_value.value().attributes;
} else {
if (property_name.is_string()) {
i32 property_index = property_name.as_string().to_int().value_or(-1);
if (property_index >= 0)
return get_own_property_descriptor(property_index);
}
auto metadata = shape().lookup(property_name.to_string_or_symbol());
if (!metadata.has_value())
return {};
value = m_storage[metadata.value().offset];
attributes = metadata.value().attributes;
}
PropertyDescriptor descriptor { attributes, {}, nullptr, nullptr };
if (value.is_native_property()) {
auto result = call_native_property_getter(value.as_native_property(), const_cast<Object*>(this));
descriptor.value = result.value_or(js_undefined());
} else if (value.is_accessor()) {
auto& pair = value.as_accessor();
if (pair.getter())
descriptor.getter = pair.getter();
if (pair.setter())
descriptor.setter = pair.setter();
} else {
descriptor.value = value.value_or(js_undefined());
}
return descriptor;
}
// Equivalent to:
// 6.2.5.4 FromPropertyDescriptor ( Desc ), https://tc39.es/ecma262/#sec-frompropertydescriptor
Value Object::get_own_property_descriptor_object(const PropertyName& property_name) const
{
VERIFY(property_name.is_valid());
auto& vm = this->vm();
auto descriptor_opt = get_own_property_descriptor(property_name);
if (!descriptor_opt.has_value())
return js_undefined();
auto descriptor = descriptor_opt.value();
auto* descriptor_object = Object::create_empty(global_object());
if (descriptor.is_data_descriptor()) {
descriptor_object->define_property(vm.names.value, descriptor.value.value_or(js_undefined()));
descriptor_object->define_property(vm.names.writable, Value(descriptor.attributes.is_writable()));
} else {
VERIFY(descriptor.is_accessor_descriptor());
descriptor_object->define_property(vm.names.get, descriptor.getter ? Value(descriptor.getter) : js_undefined());
descriptor_object->define_property(vm.names.set, descriptor.setter ? Value(descriptor.setter) : js_undefined());
}
descriptor_object->define_property(vm.names.enumerable, Value(descriptor.attributes.is_enumerable()));
descriptor_object->define_property(vm.names.configurable, Value(descriptor.attributes.is_configurable()));
return descriptor_object;
}
void Object::set_shape(Shape& new_shape)
{
m_storage.resize(new_shape.property_count());
m_shape = &new_shape;
}
bool Object::define_property(const StringOrSymbol& property_name, const Object& descriptor, bool throw_exceptions)
{
auto& vm = this->vm();
bool is_accessor_property = descriptor.has_property(vm.names.get) || descriptor.has_property(vm.names.set);
PropertyAttributes attributes;
if (descriptor.has_property(vm.names.configurable)) {
attributes.set_has_configurable();
if (descriptor.get(vm.names.configurable).value_or(Value(false)).to_boolean())
attributes.set_configurable();
if (vm.exception())
return false;
}
if (descriptor.has_property(vm.names.enumerable)) {
attributes.set_has_enumerable();
if (descriptor.get(vm.names.enumerable).value_or(Value(false)).to_boolean())
attributes.set_enumerable();
if (vm.exception())
return false;
}
if (is_accessor_property) {
if (descriptor.has_property(vm.names.value) || descriptor.has_property(vm.names.writable)) {
if (throw_exceptions)
vm.throw_exception<TypeError>(global_object(), ErrorType::AccessorValueOrWritable);
return false;
}
auto getter = descriptor.get(vm.names.get).value_or(js_undefined());
if (vm.exception())
return {};
auto setter = descriptor.get(vm.names.set).value_or(js_undefined());
if (vm.exception())
return {};
Function* getter_function { nullptr };
Function* setter_function { nullptr };
if (getter.is_function()) {
getter_function = &getter.as_function();
} else if (!getter.is_undefined()) {
vm.throw_exception<TypeError>(global_object(), ErrorType::AccessorBadField, "get");
return false;
}
if (setter.is_function()) {
setter_function = &setter.as_function();
} else if (!setter.is_undefined()) {
vm.throw_exception<TypeError>(global_object(), ErrorType::AccessorBadField, "set");
return false;
}
dbgln_if(OBJECT_DEBUG, "Defining new property {} with accessor descriptor {{ attributes={}, getter={}, setter={} }}", property_name.to_display_string(), attributes, getter, setter);
return define_property(property_name, Accessor::create(vm, getter_function, setter_function), attributes, throw_exceptions);
}
auto value = descriptor.get(vm.names.value);
if (vm.exception())
return {};
if (descriptor.has_property(vm.names.writable)) {
attributes.set_has_writable();
if (descriptor.get(vm.names.writable).value_or(Value(false)).to_boolean())
attributes.set_writable();
if (vm.exception())
return false;
}
if (vm.exception())
return {};
dbgln_if(OBJECT_DEBUG, "Defining new property {} with data descriptor {{ attributes={}, value={} }}", property_name.to_display_string(), attributes, value);
return define_property(property_name, value, attributes, throw_exceptions);
}
bool Object::define_property_without_transition(const PropertyName& property_name, Value value, PropertyAttributes attributes, bool throw_exceptions)
{
TemporaryChange change(m_transitions_enabled, false);
return define_property(property_name, value, attributes, throw_exceptions);
}
bool Object::define_property(const PropertyName& property_name, Value value, PropertyAttributes attributes, bool throw_exceptions)
{
VERIFY(property_name.is_valid());
if (property_name.is_number())
return put_own_property_by_index(property_name.as_number(), value, attributes, PutOwnPropertyMode::DefineProperty, throw_exceptions);
if (property_name.is_string()) {
i32 property_index = property_name.as_string().to_int().value_or(-1);
if (property_index >= 0)
return put_own_property_by_index(property_index, value, attributes, PutOwnPropertyMode::DefineProperty, throw_exceptions);
}
return put_own_property(property_name.to_string_or_symbol(), value, attributes, PutOwnPropertyMode::DefineProperty, throw_exceptions);
}
bool Object::define_native_accessor(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)> getter, AK::Function<Value(VM&, GlobalObject&)> setter, PropertyAttributes attribute)
{
auto& vm = this->vm();
String formatted_property_name;
if (property_name.is_string()) {
formatted_property_name = property_name.as_string();
} else {
formatted_property_name = String::formatted("[{}]", property_name.as_symbol()->description());
}
Function* getter_function = nullptr;
if (getter) {
auto name = String::formatted("get {}", formatted_property_name);
getter_function = NativeFunction::create(global_object(), name, move(getter));
getter_function->define_property_without_transition(vm.names.length, Value(0), Attribute::Configurable);
if (vm.exception())
return {};
getter_function->define_property_without_transition(vm.names.name, js_string(vm.heap(), name), Attribute::Configurable);
if (vm.exception())
return {};
}
Function* setter_function = nullptr;
if (setter) {
auto name = String::formatted("set {}", formatted_property_name);
setter_function = NativeFunction::create(global_object(), name, move(setter));
setter_function->define_property_without_transition(vm.names.length, Value(1), Attribute::Configurable);
if (vm.exception())
return {};
setter_function->define_property_without_transition(vm.names.name, js_string(vm.heap(), name), Attribute::Configurable);
if (vm.exception())
return {};
}
return define_accessor(property_name, getter_function, setter_function, attribute);
}
bool Object::define_accessor(const PropertyName& property_name, Function* getter, Function* setter, PropertyAttributes attributes, bool throw_exceptions)
{
VERIFY(property_name.is_valid());
Accessor* accessor { nullptr };
auto property_metadata = shape().lookup(property_name.to_string_or_symbol());
if (property_metadata.has_value()) {
auto existing_property = get_direct(property_metadata.value().offset);
if (existing_property.is_accessor())
accessor = &existing_property.as_accessor();
}
if (!accessor) {
accessor = Accessor::create(vm(), getter, setter);
bool definition_success = define_property(property_name, accessor, attributes, throw_exceptions);
if (vm().exception())
return {};
if (!definition_success)
return false;
} else {
if (getter)
accessor->set_getter(getter);
if (setter)
accessor->set_setter(setter);
}
return true;
}
bool Object::put_own_property(const StringOrSymbol& property_name, Value value, PropertyAttributes attributes, PutOwnPropertyMode mode, bool throw_exceptions)
{
VERIFY(!(mode == PutOwnPropertyMode::Put && value.is_accessor()));
if (value.is_accessor()) {
auto& accessor = value.as_accessor();
if (accessor.getter())
attributes.set_has_getter();
if (accessor.setter())
attributes.set_has_setter();
}
// NOTE: We disable transitions during initialize(), this makes building common runtime objects significantly faster.
// Transitions are primarily interesting when scripts add properties to objects.
if (!m_transitions_enabled && !m_shape->is_unique()) {
m_shape->add_property_without_transition(property_name, attributes);
m_storage.resize(m_shape->property_count());
m_storage[m_shape->property_count() - 1] = value;
return true;
}
auto metadata = shape().lookup(property_name);
bool new_property = !metadata.has_value();
if (!is_extensible() && new_property) {
dbgln_if(OBJECT_DEBUG, "Disallow define_property of non-extensible object");
if (throw_exceptions && vm().in_strict_mode())
vm().throw_exception<TypeError>(global_object(), ErrorType::NonExtensibleDefine, property_name.to_display_string());
return false;
}
if (new_property) {
if (!m_shape->is_unique() && shape().property_count() > 100) {
// If you add more than 100 properties to an object, let's stop doing
// transitions to avoid filling up the heap with shapes.
ensure_shape_is_unique();
}
if (m_shape->is_unique()) {
m_shape->add_property_to_unique_shape(property_name, attributes);
m_storage.resize(m_shape->property_count());
} else if (m_transitions_enabled) {
set_shape(*m_shape->create_put_transition(property_name, attributes));
} else {
m_shape->add_property_without_transition(property_name, attributes);
m_storage.resize(m_shape->property_count());
}
metadata = shape().lookup(property_name);
VERIFY(metadata.has_value());
}
if (!new_property && mode == PutOwnPropertyMode::DefineProperty && !metadata.value().attributes.is_configurable() && attributes != metadata.value().attributes) {
dbgln_if(OBJECT_DEBUG, "Disallow reconfig of non-configurable property");
if (throw_exceptions)
vm().throw_exception<TypeError>(global_object(), ErrorType::DescChangeNonConfigurable, property_name.to_display_string());
return false;
}
if (mode == PutOwnPropertyMode::DefineProperty && attributes != metadata.value().attributes) {
if (m_shape->is_unique()) {
m_shape->reconfigure_property_in_unique_shape(property_name, attributes);
} else {
set_shape(*m_shape->create_configure_transition(property_name, attributes));
}
metadata = shape().lookup(property_name);
dbgln_if(OBJECT_DEBUG, "Reconfigured property {}, new shape says offset is {} and my storage capacity is {}", property_name.to_display_string(), metadata.value().offset, m_storage.size());
}
auto value_here = m_storage[metadata.value().offset];
if (!new_property && mode == PutOwnPropertyMode::Put && !value_here.is_accessor() && !metadata.value().attributes.is_writable()) {
dbgln_if(OBJECT_DEBUG, "Disallow write to non-writable property");
if (throw_exceptions && vm().in_strict_mode())
vm().throw_exception<TypeError>(global_object(), ErrorType::DescWriteNonWritable, property_name.to_display_string());
return false;
}
if (value.is_empty())
return true;
if (value_here.is_native_property()) {
call_native_property_setter(value_here.as_native_property(), this, value);
} else {
m_storage[metadata.value().offset] = value;
}
return true;
}
bool Object::put_own_property_by_index(u32 property_index, Value value, PropertyAttributes attributes, PutOwnPropertyMode mode, bool throw_exceptions)
{
VERIFY(!(mode == PutOwnPropertyMode::Put && value.is_accessor()));
auto existing_property = m_indexed_properties.get(nullptr, property_index, false);
auto new_property = !existing_property.has_value();
if (!is_extensible() && new_property) {
dbgln_if(OBJECT_DEBUG, "Disallow define_property of non-extensible object");
if (throw_exceptions && vm().in_strict_mode())
vm().throw_exception<TypeError>(global_object(), ErrorType::NonExtensibleDefine, property_index);
return false;
}
if (value.is_accessor()) {
auto& accessor = value.as_accessor();
if (accessor.getter())
attributes.set_has_getter();
if (accessor.setter())
attributes.set_has_setter();
}
PropertyAttributes existing_attributes = new_property ? 0 : existing_property.value().attributes;
if (!new_property && mode == PutOwnPropertyMode::DefineProperty && !existing_attributes.is_configurable() && attributes != existing_attributes) {
dbgln_if(OBJECT_DEBUG, "Disallow reconfig of non-configurable property");
if (throw_exceptions)
vm().throw_exception<TypeError>(global_object(), ErrorType::DescChangeNonConfigurable, property_index);
return false;
}
auto value_here = new_property ? Value() : existing_property.value().value;
if (!new_property && mode == PutOwnPropertyMode::Put && !value_here.is_accessor() && !existing_attributes.is_writable()) {
dbgln_if(OBJECT_DEBUG, "Disallow write to non-writable property");
return false;
}
if (value.is_empty())
return true;
if (value_here.is_native_property()) {
call_native_property_setter(value_here.as_native_property(), this, value);
} else {
m_indexed_properties.put(this, property_index, value, attributes, mode == PutOwnPropertyMode::Put);
}
return true;
}
bool Object::delete_property(const PropertyName& property_name)
{
VERIFY(property_name.is_valid());
if (property_name.is_number())
return m_indexed_properties.remove(property_name.as_number());
if (property_name.is_string()) {
i32 property_index = property_name.as_string().to_int().value_or(-1);
if (property_index >= 0)
return m_indexed_properties.remove(property_index);
}
auto metadata = shape().lookup(property_name.to_string_or_symbol());
if (!metadata.has_value())
return true;
if (!metadata.value().attributes.is_configurable())
return false;
size_t deleted_offset = metadata.value().offset;
ensure_shape_is_unique();
shape().remove_property_from_unique_shape(property_name.to_string_or_symbol(), deleted_offset);
m_storage.remove(deleted_offset);
return true;
}
void Object::ensure_shape_is_unique()
{
if (shape().is_unique())
return;
m_shape = m_shape->create_unique_clone();
}
Value Object::get_by_index(u32 property_index) const
{
const Object* object = this;
while (object) {
if (is<StringObject>(*object)) {
auto& string = static_cast<const StringObject&>(*object).primitive_string().string();
if (property_index < string.length())
return js_string(heap(), string.substring(property_index, 1));
} else if (static_cast<size_t>(property_index) < object->m_indexed_properties.array_like_size()) {
auto result = object->m_indexed_properties.get(const_cast<Object*>(this), property_index);
if (vm().exception())
return {};
if (result.has_value() && !result.value().value.is_empty())
return result.value().value;
}
object = object->prototype();
if (vm().exception())
return {};
}
return {};
}
Value Object::get(const PropertyName& property_name, Value receiver, bool without_side_effects) const
{
VERIFY(property_name.is_valid());
if (property_name.is_number())
return get_by_index(property_name.as_number());
if (property_name.is_string()) {
auto& property_string = property_name.as_string();
i32 property_index = property_string.to_int().value_or(-1);
if (property_index >= 0)
return get_by_index(property_index);
}
if (receiver.is_empty())
receiver = Value(this);
const Object* object = this;
while (object) {
auto value = object->get_own_property(property_name, receiver, without_side_effects);
if (vm().exception())
return {};
if (!value.is_empty())
return value;
object = object->prototype();
if (vm().exception())
return {};
}
return {};
}
Value Object::get_without_side_effects(const PropertyName& property_name) const
{
TemporaryClearException clear_exception(vm());
return get(property_name, {}, true);
}
bool Object::put_by_index(u32 property_index, Value value)
{
VERIFY(!value.is_empty());
// If there's a setter in the prototype chain, we go to the setter.
// Otherwise, it goes in the own property storage.
Object* object = this;
while (object) {
auto existing_value = object->m_indexed_properties.get(nullptr, property_index, false);
if (existing_value.has_value()) {
auto value_here = existing_value.value();
if (value_here.value.is_accessor()) {
value_here.value.as_accessor().call_setter(object, value);
return true;
}
if (value_here.value.is_native_property()) {
// FIXME: Why doesn't put_by_index() receive the receiver value from put()?!
auto receiver = this;
call_native_property_setter(value_here.value.as_native_property(), receiver, value);
return true;
}
}
object = object->prototype();
if (vm().exception())
return {};
}
return put_own_property_by_index(property_index, value, default_attributes, PutOwnPropertyMode::Put);
}
bool Object::put(const PropertyName& property_name, Value value, Value receiver)
{
VERIFY(property_name.is_valid());
if (property_name.is_number())
return put_by_index(property_name.as_number(), value);
VERIFY(!value.is_empty());
if (property_name.is_string()) {
auto& property_string = property_name.as_string();
i32 property_index = property_string.to_int().value_or(-1);
if (property_index >= 0)
return put_by_index(property_index, value);
}
auto string_or_symbol = property_name.to_string_or_symbol();
if (receiver.is_empty())
receiver = Value(this);
// If there's a setter in the prototype chain, we go to the setter.
// Otherwise, it goes in the own property storage.
Object* object = this;
while (object) {
auto metadata = object->shape().lookup(string_or_symbol);
if (metadata.has_value()) {
auto value_here = object->m_storage[metadata.value().offset];
if (value_here.is_accessor()) {
value_here.as_accessor().call_setter(receiver, value);
return true;
}
if (value_here.is_native_property()) {
call_native_property_setter(value_here.as_native_property(), receiver, value);
return true;
}
}
object = object->prototype();
if (vm().exception())
return false;
}
return put_own_property(string_or_symbol, value, default_attributes, PutOwnPropertyMode::Put);
}
bool Object::define_native_function(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)> native_function, i32 length, PropertyAttributes attribute)
{
auto& vm = this->vm();
String function_name;
if (property_name.is_string()) {
function_name = property_name.as_string();
} else {
function_name = String::formatted("[{}]", property_name.as_symbol()->description());
}
auto* function = NativeFunction::create(global_object(), function_name, move(native_function));
function->define_property_without_transition(vm.names.length, Value(length), Attribute::Configurable);
if (vm.exception())
return {};
function->define_property_without_transition(vm.names.name, js_string(vm.heap(), function_name), Attribute::Configurable);
if (vm.exception())
return {};
return define_property(property_name, function, attribute);
}
bool Object::define_native_property(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)> getter, AK::Function<void(VM&, GlobalObject&, Value)> setter, PropertyAttributes attribute)
{
return define_property(property_name, heap().allocate_without_global_object<NativeProperty>(move(getter), move(setter)), attribute);
}
// 20.1.2.3.1 ObjectDefineProperties ( O, Properties ), https://tc39.es/ecma262/#sec-objectdefineproperties
void Object::define_properties(Value properties)
{
auto& vm = this->vm();
auto* props = properties.to_object(global_object());
if (!props)
return;
auto keys = props->get_own_properties(PropertyKind::Key);
if (vm.exception())
return;
struct NameAndDescriptor {
PropertyName name;
PropertyDescriptor descriptor;
};
Vector<NameAndDescriptor> descriptors;
for (auto& key : keys) {
auto property_name = PropertyName::from_value(global_object(), key);
auto property_descriptor = props->get_own_property_descriptor(property_name);
if (property_descriptor.has_value() && property_descriptor->attributes.is_enumerable()) {
auto descriptor_object = props->get(property_name);
if (vm.exception())
return;
if (!descriptor_object.is_object()) {
vm.throw_exception<TypeError>(global_object(), ErrorType::NotAnObject, descriptor_object.to_string_without_side_effects());
return;
}
auto descriptor = PropertyDescriptor::from_dictionary(vm, descriptor_object.as_object());
if (vm.exception())
return;
descriptors.append({ property_name, descriptor });
}
}
for (auto& [name, descriptor] : descriptors) {
// FIXME: The spec has both of this handled by DefinePropertyOrThrow(O, P, desc).
// We should invest some time in improving object property handling, it not being
// super close to the spec makes this and other things unnecessarily complicated.
if (descriptor.is_accessor_descriptor())
define_accessor(name, descriptor.getter, descriptor.setter, descriptor.attributes);
else
define_property(name, descriptor.value, descriptor.attributes);
}
}
void Object::visit_edges(Cell::Visitor& visitor)
{
Cell::visit_edges(visitor);
visitor.visit(m_shape);
for (auto& value : m_storage)
visitor.visit(value);
m_indexed_properties.for_each_value([&visitor](auto& value) {
visitor.visit(value);
});
}
bool Object::has_property(const PropertyName& property_name) const
{
const Object* object = this;
while (object) {
if (object->has_own_property(property_name))
return true;
object = object->prototype();
if (vm().exception())
return false;
}
return false;
}
bool Object::has_own_property(const PropertyName& property_name) const
{
VERIFY(property_name.is_valid());
auto has_indexed_property = [&](u32 index) -> bool {
if (is<StringObject>(*this))
return index < static_cast<const StringObject*>(this)->primitive_string().string().length();
return m_indexed_properties.has_index(index);
};
if (property_name.is_number())
return has_indexed_property(property_name.as_number());
if (property_name.is_string()) {
i32 property_index = property_name.as_string().to_int().value_or(-1);
if (property_index >= 0)
return has_indexed_property(property_index);
}
return shape().lookup(property_name.to_string_or_symbol()).has_value();
}
Value Object::ordinary_to_primitive(Value::PreferredType preferred_type) const
{
VERIFY(preferred_type == Value::PreferredType::String || preferred_type == Value::PreferredType::Number);
auto& vm = this->vm();
Vector<FlyString, 2> method_names;
if (preferred_type == Value::PreferredType::String)
method_names = { vm.names.toString, vm.names.valueOf };
else
method_names = { vm.names.valueOf, vm.names.toString };
for (auto& method_name : method_names) {
auto method = get(method_name);
if (vm.exception())
return {};
if (method.is_function()) {
auto result = vm.call(method.as_function(), const_cast<Object*>(this));
if (!result.is_object())
return result;
}
}
vm.throw_exception<TypeError>(global_object(), ErrorType::Convert, "object", preferred_type == Value::PreferredType::String ? "string" : "number");
return {};
}
// 20.5.8.1 InstallErrorCause ( O, options ), https://tc39.es/proposal-error-cause/#sec-errorobjects-install-error-cause
void Object::install_error_cause(Value options)
{
auto& vm = this->vm();
if (!options.is_object())
return;
auto& options_object = options.as_object();
if (!options_object.has_property(vm.names.cause))
return;
auto cause = options_object.get(vm.names.cause).value_or(js_undefined());
if (vm.exception())
return;
define_property(vm.names.cause, cause, Attribute::Writable | Attribute::Configurable);
}
Value Object::invoke_internal(const StringOrSymbol& property_name, Optional<MarkedValueList> arguments)
{
auto& vm = this->vm();
auto property = get(property_name).value_or(js_undefined());
if (vm.exception())
return {};
if (!property.is_function()) {
vm.throw_exception<TypeError>(global_object(), ErrorType::NotAFunction, property.to_string_without_side_effects());
return {};
}
return vm.call(property.as_function(), this, move(arguments));
}
Value Object::call_native_property_getter(NativeProperty& property, Value this_value) const
{
auto& vm = this->vm();
CallFrame call_frame;
if (auto* interpreter = vm.interpreter_if_exists())
call_frame.current_node = interpreter->current_node();
call_frame.is_strict_mode = vm.in_strict_mode();
call_frame.this_value = this_value;
vm.push_call_frame(call_frame, global_object());
if (vm.exception())
return {};
auto result = property.get(vm, global_object());
vm.pop_call_frame();
return result;
}
void Object::call_native_property_setter(NativeProperty& property, Value this_value, Value setter_value) const
{
auto& vm = this->vm();
CallFrame call_frame;
if (auto* interpreter = vm.interpreter_if_exists())
call_frame.current_node = interpreter->current_node();
call_frame.is_strict_mode = vm.in_strict_mode();
call_frame.this_value = this_value;
vm.push_call_frame(call_frame, global_object());
if (vm.exception())
return;
property.set(vm, global_object(), setter_value);
vm.pop_call_frame();
}
}
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