ladybird/Userland/Libraries/LibJS/Heap/Handle.h
2022-02-07 21:05:30 +01:00

120 lines
2.4 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Badge.h>
#include <AK/IntrusiveList.h>
#include <AK/Noncopyable.h>
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
#include <LibJS/Forward.h>
#include <LibJS/Runtime/Environment.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
class HandleImpl : public RefCounted<HandleImpl> {
AK_MAKE_NONCOPYABLE(HandleImpl);
AK_MAKE_NONMOVABLE(HandleImpl);
public:
~HandleImpl();
Cell* cell() { return m_cell; }
const Cell* cell() const { return m_cell; }
private:
template<class T>
friend class Handle;
explicit HandleImpl(Cell*);
Cell* m_cell { nullptr };
IntrusiveListNode<HandleImpl> m_list_node;
public:
using List = IntrusiveList<&HandleImpl::m_list_node>;
};
template<class T>
class Handle {
public:
Handle() = default;
static Handle create(T* cell)
{
return Handle(adopt_ref(*new HandleImpl(cell)));
}
T* cell() { return static_cast<T*>(m_impl->cell()); }
const T* cell() const { return static_cast<const T*>(m_impl->cell()); }
bool is_null() const { return m_impl.is_null(); }
T* operator->() { return cell(); }
T const* operator->() const { return cell(); }
private:
explicit Handle(NonnullRefPtr<HandleImpl> impl)
: m_impl(move(impl))
{
}
RefPtr<HandleImpl> m_impl;
};
template<class T>
inline Handle<T> make_handle(T* cell)
{
return Handle<T>::create(cell);
}
template<class T>
inline Handle<T> make_handle(T& cell)
{
return Handle<T>::create(&cell);
}
template<>
class Handle<Value> {
public:
Handle() = default;
static Handle create(Value value)
{
if (value.is_cell())
return Handle(value, &value.as_cell());
return Handle(value);
}
auto cell() { return m_handle.cell(); }
auto cell() const { return m_handle.cell(); }
auto value() const { return m_value; }
bool is_null() const { return m_handle.is_null(); }
private:
explicit Handle(Value value)
: m_value(value)
{
}
explicit Handle(Value value, Cell* cell)
: m_value(value)
, m_handle(Handle<Cell>::create(cell))
{
}
Value m_value;
Handle<Cell> m_handle;
};
inline Handle<Value> make_handle(Value value)
{
return Handle<Value>::create(value);
}
}