serenity/Userland/Libraries/LibJS/Runtime/Object.h

/*
 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/HashMap.h>
#include <AK/String.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/Cell.h>
#include <LibJS/Runtime/IndexedProperties.h>
#include <LibJS/Runtime/MarkedValueList.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/PropertyName.h>
#include <LibJS/Runtime/Shape.h>
#include <LibJS/Runtime/Value.h>

namespace JS {

#define JS_OBJECT(class_, base_class) \
public:                               \
    using Base = base_class;          \
    virtual const char* class_name() const override { return #class_; }

struct PropertyDescriptor {
    PropertyAttributes attributes;
    Value value;
    Function* getter { nullptr };
    Function* setter { nullptr };

    static PropertyDescriptor from_dictionary(VM&, const Object&);

    bool is_accessor_descriptor() const { return getter || setter; }
    bool is_data_descriptor() const { return !(value.is_empty() && !attributes.has_writable()); }
    bool is_generic_descriptor() const { return !is_accessor_descriptor() && !is_data_descriptor(); }
};

class Object : public Cell {
public:
    static Object* create_empty(GlobalObject&);

    explicit Object(Object& prototype);
    explicit Object(Shape&);
    virtual void initialize(GlobalObject&) override;
    virtual ~Object();

    enum class PropertyKind {
        Key,
        Value,
        KeyAndValue,
    };

    enum class GetOwnPropertyReturnType {
        All,
        StringOnly,
        SymbolOnly,
    };

    enum class PutOwnPropertyMode {
        Put,
        DefineProperty,
    };

    enum class IntegrityLevel {
        Sealed,
        Frozen,
    };

    Shape& shape() { return *m_shape; }
    const Shape& shape() const { return *m_shape; }

    GlobalObject& global_object() const { return *shape().global_object(); }

    virtual Value get(const PropertyName&, Value receiver = {}, bool without_side_effects = false) const;
    Value get_without_side_effects(const PropertyName&) const;

    virtual bool has_property(const PropertyName&) const;
    bool has_own_property(const PropertyName&) const;

    virtual bool put(const PropertyName&, Value, Value receiver = {});

    Value get_own_property(const PropertyName&, Value receiver, bool without_side_effects = false) const;
    MarkedValueList get_own_properties(PropertyKind, bool only_enumerable_properties = false, GetOwnPropertyReturnType = GetOwnPropertyReturnType::All) const;
    MarkedValueList get_enumerable_own_property_names(PropertyKind) const;
    virtual Optional<PropertyDescriptor> get_own_property_descriptor(const PropertyName&) const;
    Value get_own_property_descriptor_object(const PropertyName&) const;

    virtual bool define_property(const StringOrSymbol& property_name, const Object& descriptor, bool throw_exceptions = true);
    bool define_property(const PropertyName&, Value value, PropertyAttributes attributes = default_attributes, bool throw_exceptions = true);
    bool define_property_without_transition(const PropertyName&, Value value, PropertyAttributes attributes = default_attributes, bool throw_exceptions = true);
    bool define_accessor(const PropertyName&, Function* getter, Function* setter, PropertyAttributes attributes = default_attributes, bool throw_exceptions = true);

    bool define_native_function(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)>, i32 length = 0, PropertyAttributes attributes = default_attributes);
    bool define_native_property(const StringOrSymbol& property_name, AK::Function<Value(VM&, GlobalObject&)> getter, AK::Function<void(VM&, GlobalObject&, Value)> setter, PropertyAttributes attributes = default_attributes);

    void define_properties(Value properties);

    virtual bool delete_property(const PropertyName&);

    virtual bool is_array() const { return false; }
    virtual bool is_function() const { return false; }
    virtual bool is_typed_array() const { return false; }
    virtual bool is_string_object() const { return false; }
    virtual bool is_global_object() const { return false; }

    virtual const char* class_name() const override { return "Object"; }
    virtual void visit_edges(Cell::Visitor&) override;

    virtual Object* prototype();
    virtual const Object* prototype() const;
    virtual bool set_prototype(Object* prototype);
    bool has_prototype(const Object* prototype) const;

    virtual bool is_extensible() const { return m_is_extensible; }
    virtual bool prevent_extensions();

    bool set_integrity_level(IntegrityLevel);
    bool test_integrity_level(IntegrityLevel);

    virtual Value value_of() const { return Value(const_cast<Object*>(this)); }
    virtual Value ordinary_to_primitive(Value::PreferredType preferred_type) const;

    Value get_direct(size_t index) const { return m_storage[index]; }

    const IndexedProperties& indexed_properties() const { return m_indexed_properties; }
    IndexedProperties& indexed_properties() { return m_indexed_properties; }
    void set_indexed_property_elements(Vector<Value>&& values) { m_indexed_properties = IndexedProperties(move(values)); }

    [[nodiscard]] Value invoke_internal(const StringOrSymbol& property_name, Optional<MarkedValueList> arguments);

    template<typename... Args>
    [[nodiscard]] ALWAYS_INLINE Value invoke(const StringOrSymbol& property_name, Args... args)
    {
        if constexpr (sizeof...(Args) > 0) {
            MarkedValueList arglist { heap() };
            (..., arglist.append(move(args)));
            return invoke(property_name, move(arglist));
        }

        return invoke(property_name);
    }

    void ensure_shape_is_unique();

    void enable_transitions() { m_transitions_enabled = true; }
    void disable_transitions() { m_transitions_enabled = false; }

    template<typename T>
    bool fast_is() const = delete;

protected:
    enum class GlobalObjectTag { Tag };
    enum class ConstructWithoutPrototypeTag { Tag };
    explicit Object(GlobalObjectTag);
    Object(ConstructWithoutPrototypeTag, GlobalObject&);

    virtual Value get_by_index(u32 property_index) const;
    virtual bool put_by_index(u32 property_index, Value);

private:
    bool put_own_property(const StringOrSymbol& property_name, Value, PropertyAttributes attributes, PutOwnPropertyMode = PutOwnPropertyMode::Put, bool throw_exceptions = true);
    bool put_own_property_by_index(u32 property_index, Value, PropertyAttributes attributes, PutOwnPropertyMode = PutOwnPropertyMode::Put, bool throw_exceptions = true);

    Value call_native_property_getter(NativeProperty& property, Value this_value) const;
    void call_native_property_setter(NativeProperty& property, Value this_value, Value) const;

    void set_shape(Shape&);

    bool m_is_extensible { true };
    bool m_transitions_enabled { true };
    Shape* m_shape { nullptr };
    Vector<Value> m_storage;
    IndexedProperties m_indexed_properties;
};

template<>
[[nodiscard]] ALWAYS_INLINE Value Object::invoke(const StringOrSymbol& property_name, MarkedValueList arguments) { return invoke_internal(property_name, move(arguments)); }

template<>
[[nodiscard]] ALWAYS_INLINE Value Object::invoke(const StringOrSymbol& property_name, Optional<MarkedValueList> arguments) { return invoke_internal(property_name, move(arguments)); }

template<>
[[nodiscard]] ALWAYS_INLINE Value Object::invoke(const StringOrSymbol& property_name) { return invoke(property_name, Optional<MarkedValueList> {}); }

}