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/*
* Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <AK/OwnPtr.h>
#include <AK/WeakPtr.h>
#include <AK/Weakable.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/Cell.h>
#include <LibJS/Runtime/PropertyAttributes.h>
#include <LibJS/Runtime/StringOrSymbol.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
struct PropertyMetadata {
size_t offset { 0 };
PropertyAttributes attributes { 0 };
};
struct TransitionKey {
StringOrSymbol property_name;
PropertyAttributes attributes { 0 };
bool operator==(const TransitionKey& other) const
{
return property_name == other.property_name && attributes == other.attributes;
}
};
class Shape final
: public Cell
, public Weakable<Shape> {
public:
virtual ~Shape() override;
enum class TransitionType {
Invalid,
Put,
Configure,
Prototype,
};
enum class ShapeWithoutGlobalObjectTag { Tag };
explicit Shape(ShapeWithoutGlobalObjectTag);
explicit Shape(Object& global_object);
Shape(Shape& previous_shape, const StringOrSymbol& property_name, PropertyAttributes attributes, TransitionType);
Shape(Shape& previous_shape, Object* new_prototype);
Shape* create_put_transition(const StringOrSymbol&, PropertyAttributes attributes);
Shape* create_configure_transition(const StringOrSymbol&, PropertyAttributes attributes);
Shape* create_prototype_transition(Object* new_prototype);
void add_property_without_transition(const StringOrSymbol&, PropertyAttributes);
void add_property_without_transition(PropertyName const&, PropertyAttributes);
bool is_unique() const { return m_unique; }
Shape* create_unique_clone() const;
GlobalObject* global_object() const;
Object* prototype() { return m_prototype; }
const Object* prototype() const { return m_prototype; }
Optional<PropertyMetadata> lookup(const StringOrSymbol&) const;
const HashMap<StringOrSymbol, PropertyMetadata>& property_table() const;
size_t property_count() const;
struct Property {
StringOrSymbol key;
PropertyMetadata value;
};
Vector<Property> property_table_ordered() const;
void set_prototype_without_transition(Object* new_prototype) { m_prototype = new_prototype; }
void remove_property_from_unique_shape(const StringOrSymbol&, size_t offset);
void add_property_to_unique_shape(const StringOrSymbol&, PropertyAttributes attributes);
void reconfigure_property_in_unique_shape(const StringOrSymbol& property_name, PropertyAttributes attributes);
private:
virtual const char* class_name() const override { return "Shape"; }
virtual void visit_edges(Visitor&) override;
#ifdef JS_TRACK_ZOMBIE_CELLS
virtual void did_become_zombie() override;
#endif
Shape* get_or_prune_cached_forward_transition(TransitionKey const&);
Shape* get_or_prune_cached_prototype_transition(Object* prototype);
void ensure_property_table() const;
PropertyAttributes m_attributes { 0 };
TransitionType m_transition_type : 6 { TransitionType::Invalid };
bool m_unique : 1 { false };
Object* m_global_object { nullptr };
mutable OwnPtr<HashMap<StringOrSymbol, PropertyMetadata>> m_property_table;
HashMap<TransitionKey, WeakPtr<Shape>> m_forward_transitions;
HashMap<Object*, WeakPtr<Shape>> m_prototype_transitions;
Shape* m_previous { nullptr };
StringOrSymbol m_property_name;
Object* m_prototype { nullptr };
size_t m_property_count { 0 };
};
}
template<>
struct AK::Traits<JS::TransitionKey> : public GenericTraits<JS::TransitionKey> {
static unsigned hash(const JS::TransitionKey& key)
{
return pair_int_hash(key.attributes.bits(), Traits<JS::StringOrSymbol>::hash(key.property_name));
}
};
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