ladybird/AK/WeakPtr.h
Ali Mohammad Pur f96a3c002a Everywhere: Stop shoving things into ::std and mentioning them as such
Note that this still keeps the old behaviour of putting things in std by
default on serenity so the tools can be happy, but if USING_AK_GLOBALLY
is unset, AK behaves like a good citizen and doesn't try to put things
in the ::std namespace.

std::nothrow_t and its friends get to stay because I'm being told that
compilers assume things about them and I can't yeet them into a
different namespace...for now.
2022-12-14 11:44:32 +01:00

211 lines
4.6 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Weakable.h>
namespace AK {
template<typename T>
class [[nodiscard]] WeakPtr {
template<typename U>
friend class Weakable;
public:
WeakPtr() = default;
template<SameAs<OptionalNone> V>
WeakPtr(V) { }
template<SameAs<OptionalNone> V>
WeakPtr& operator=(V)
{
clear();
return *this;
}
template<typename U>
WeakPtr(WeakPtr<U> const& other)
requires(IsBaseOf<T, U>)
: m_link(other.m_link)
{
}
template<typename U>
WeakPtr(WeakPtr<U>&& other)
requires(IsBaseOf<T, U>)
: m_link(other.take_link())
{
}
template<typename U>
WeakPtr& operator=(WeakPtr<U>&& other)
requires(IsBaseOf<T, U>)
{
m_link = other.take_link();
return *this;
}
template<typename U>
WeakPtr& operator=(WeakPtr<U> const& other)
requires(IsBaseOf<T, U>)
{
if ((void const*)this != (void const*)&other)
m_link = other.m_link;
return *this;
}
WeakPtr& operator=(nullptr_t)
{
clear();
return *this;
}
template<typename U>
WeakPtr(U const& object)
requires(IsBaseOf<T, U>)
: m_link(object.template make_weak_ptr<U>().take_link())
{
}
template<typename U>
WeakPtr(U const* object)
requires(IsBaseOf<T, U>)
{
if (object)
m_link = object->template make_weak_ptr<U>().take_link();
}
template<typename U>
WeakPtr(RefPtr<U> const& object)
requires(IsBaseOf<T, U>)
{
if (object)
m_link = object->template make_weak_ptr<U>().take_link();
}
template<typename U>
WeakPtr(NonnullRefPtr<U> const& object)
requires(IsBaseOf<T, U>)
{
m_link = object->template make_weak_ptr<U>().take_link();
}
template<typename U>
WeakPtr& operator=(U const& object)
requires(IsBaseOf<T, U>)
{
m_link = object.template make_weak_ptr<U>().take_link();
return *this;
}
template<typename U>
WeakPtr& operator=(U const* object)
requires(IsBaseOf<T, U>)
{
if (object)
m_link = object->template make_weak_ptr<U>().take_link();
else
m_link = nullptr;
return *this;
}
template<typename U>
WeakPtr& operator=(RefPtr<U> const& object)
requires(IsBaseOf<T, U>)
{
if (object)
m_link = object->template make_weak_ptr<U>().take_link();
else
m_link = nullptr;
return *this;
}
template<typename U>
WeakPtr& operator=(NonnullRefPtr<U> const& object)
requires(IsBaseOf<T, U>)
{
m_link = object->template make_weak_ptr<U>().take_link();
return *this;
}
[[nodiscard]] RefPtr<T> strong_ref() const
{
return RefPtr<T> { ptr() };
}
T* ptr() const { return unsafe_ptr(); }
T* operator->() const { return unsafe_ptr(); }
operator T*() const { return unsafe_ptr(); }
[[nodiscard]] T* unsafe_ptr() const
{
if (m_link)
return m_link->template unsafe_ptr<T>();
return nullptr;
}
[[nodiscard]] T const* value() const { return unsafe_ptr(); }
[[nodiscard]] T* value() { return unsafe_ptr(); }
operator bool() const { return m_link ? !m_link->is_null() : false; }
[[nodiscard]] bool is_null() const { return !m_link || m_link->is_null(); }
[[nodiscard]] bool has_value() const { return !is_null(); }
void clear() { m_link = nullptr; }
[[nodiscard]] RefPtr<WeakLink> take_link() { return move(m_link); }
private:
WeakPtr(RefPtr<WeakLink> const& link)
: m_link(link)
{
}
RefPtr<WeakLink> m_link;
};
template<typename T>
template<typename U>
inline ErrorOr<WeakPtr<U>> Weakable<T>::try_make_weak_ptr() const
{
if (!m_link)
m_link = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) WeakLink(const_cast<T&>(static_cast<T const&>(*this)))));
return WeakPtr<U>(m_link);
}
template<typename T>
struct Formatter<WeakPtr<T>> : Formatter<T const*> {
ErrorOr<void> format(FormatBuilder& builder, WeakPtr<T> const& value)
{
return Formatter<T const*>::format(builder, value.ptr());
}
};
template<typename T>
ErrorOr<WeakPtr<T>> try_make_weak_ptr_if_nonnull(T const* ptr)
{
if (ptr) {
return ptr->template try_make_weak_ptr<T>();
}
return WeakPtr<T> {};
}
template<typename T>
WeakPtr<T> make_weak_ptr_if_nonnull(T const* ptr)
{
return MUST(try_make_weak_ptr_if_nonnull(ptr));
}
}
#if USING_AK_GLOBALLY
using AK::WeakPtr;
#endif