ladybird/Libraries/LibJS/Runtime/Shape.h
2025-06-30 10:50:36 -06:00

156 lines
5.2 KiB
C++

/*
* Copyright (c) 2020-2024, Andreas Kling <andreas@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <AK/OwnPtr.h>
#include <AK/StringView.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/PropertyKey.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
struct PropertyMetadata {
u32 offset { 0 };
PropertyAttributes attributes { 0 };
};
struct TransitionKey {
PropertyKey property_key;
PropertyAttributes attributes { 0 };
bool operator==(TransitionKey const& other) const
{
return property_key == other.property_key && attributes == other.attributes;
}
};
class JS_API PrototypeChainValidity final : public Cell
, public Weakable<PrototypeChainValidity> {
GC_CELL(PrototypeChainValidity, Cell);
GC_DECLARE_ALLOCATOR(PrototypeChainValidity);
public:
[[nodiscard]] bool is_valid() const { return m_valid; }
void set_valid(bool valid) { m_valid = valid; }
private:
bool m_valid { true };
size_t padding { 0 };
};
class JS_API Shape final : public Cell
, public Weakable<Shape> {
GC_CELL(Shape, Cell);
GC_DECLARE_ALLOCATOR(Shape);
public:
virtual ~Shape() override;
enum class TransitionType : u8 {
Invalid,
Put,
Configure,
Prototype,
Delete,
CacheableDictionary,
UncacheableDictionary,
};
[[nodiscard]] GC::Ref<Shape> create_put_transition(PropertyKey const&, PropertyAttributes attributes);
[[nodiscard]] GC::Ref<Shape> create_configure_transition(PropertyKey const&, PropertyAttributes attributes);
[[nodiscard]] GC::Ref<Shape> create_prototype_transition(Object* new_prototype);
[[nodiscard]] GC::Ref<Shape> create_delete_transition(PropertyKey const&);
[[nodiscard]] GC::Ref<Shape> create_cacheable_dictionary_transition();
[[nodiscard]] GC::Ref<Shape> create_uncacheable_dictionary_transition();
[[nodiscard]] GC::Ref<Shape> clone_for_prototype();
void add_property_without_transition(PropertyKey const&, PropertyAttributes);
void remove_property_without_transition(PropertyKey const&, u32 offset);
void set_property_attributes_without_transition(PropertyKey const&, PropertyAttributes);
[[nodiscard]] bool is_cacheable() const { return m_cacheable; }
[[nodiscard]] bool is_dictionary() const { return m_dictionary; }
[[nodiscard]] bool is_cacheable_dictionary() const { return m_dictionary && m_cacheable; }
[[nodiscard]] bool is_uncacheable_dictionary() const { return m_dictionary && !m_cacheable; }
[[nodiscard]] bool is_prototype_shape() const { return m_is_prototype_shape; }
void set_prototype_shape();
GC::Ptr<PrototypeChainValidity> prototype_chain_validity() const { return m_prototype_chain_validity; }
Realm& realm() const { return m_realm; }
Object* prototype() { return m_prototype; }
Object const* prototype() const { return m_prototype; }
Optional<PropertyMetadata> lookup(PropertyKey const&) const;
OrderedHashMap<PropertyKey, PropertyMetadata> const& property_table() const;
u32 property_count() const { return m_property_count; }
struct Property {
PropertyKey key;
PropertyMetadata value;
};
void set_prototype_without_transition(Object* new_prototype);
private:
explicit Shape(Realm&);
Shape(Shape& previous_shape, PropertyKey const& property_key, PropertyAttributes attributes, TransitionType);
Shape(Shape& previous_shape, PropertyKey const& property_key, TransitionType);
Shape(Shape& previous_shape, Object* new_prototype);
void invalidate_prototype_if_needed_for_new_prototype(GC::Ref<Shape> new_prototype_shape);
void invalidate_all_prototype_chains_leading_to_this();
virtual void visit_edges(Visitor&) override;
[[nodiscard]] GC::Ptr<Shape> get_or_prune_cached_forward_transition(TransitionKey const&);
[[nodiscard]] GC::Ptr<Shape> get_or_prune_cached_prototype_transition(Object* prototype);
[[nodiscard]] GC::Ptr<Shape> get_or_prune_cached_delete_transition(PropertyKey const&);
void ensure_property_table() const;
GC::Ref<Realm> m_realm;
mutable OwnPtr<OrderedHashMap<PropertyKey, PropertyMetadata>> m_property_table;
OwnPtr<HashMap<TransitionKey, WeakPtr<Shape>>> m_forward_transitions;
OwnPtr<HashMap<GC::Ptr<Object>, WeakPtr<Shape>>> m_prototype_transitions;
OwnPtr<HashMap<PropertyKey, WeakPtr<Shape>>> m_delete_transitions;
GC::Ptr<Shape> m_previous;
Optional<PropertyKey> m_property_key;
GC::Ptr<Object> m_prototype;
GC::Ptr<PrototypeChainValidity> m_prototype_chain_validity;
u32 m_property_count { 0 };
PropertyAttributes m_attributes { 0 };
TransitionType m_transition_type { TransitionType::Invalid };
bool m_dictionary : 1 { false };
bool m_cacheable : 1 { true };
bool m_is_prototype_shape : 1 { false };
};
}
template<>
struct AK::Traits<JS::TransitionKey> : public DefaultTraits<JS::TransitionKey> {
static unsigned hash(const JS::TransitionKey& key)
{
return pair_int_hash(key.attributes.bits(), Traits<JS::PropertyKey>::hash(key.property_key));
}
};