ladybird/AK/OwnPtr.h
Daniel Bertalan 3c6bdb8a61 AK: Make smart pointer factories work with aggregates
Aggregate initialization with brace-enclosed parameters is a
[C++20 feature][1] not yet implemented by Clang. This caused compile
errors if we tried to use the factory functions to create smart pointers
to aggregates.

As a (temporary) fix, [the LWG's previously proposed solution][2] is
implemented by this commit.

Now, wherever it's not possible to direct-initialize, aggregate
initialization is performed.

[1]:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0960r3.html
[2]: http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#2089
2021-07-03 01:56:31 +04:30

235 lines
4.9 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/NonnullOwnPtr.h>
#include <AK/RefCounted.h>
namespace AK {
template<typename T>
class OwnPtr {
public:
OwnPtr() = default;
OwnPtr(decltype(nullptr))
: m_ptr(nullptr)
{
}
OwnPtr(OwnPtr&& other)
: m_ptr(other.leak_ptr())
{
}
template<typename U>
OwnPtr(NonnullOwnPtr<U>&& other)
: m_ptr(other.leak_ptr())
{
}
template<typename U>
OwnPtr(OwnPtr<U>&& other)
: m_ptr(other.leak_ptr())
{
}
~OwnPtr()
{
clear();
#ifdef SANITIZE_PTRS
if constexpr (sizeof(T*) == 8)
m_ptr = (T*)(0xe1e1e1e1e1e1e1e1);
else
m_ptr = (T*)(0xe1e1e1e1);
#endif
}
OwnPtr(const OwnPtr&) = delete;
template<typename U>
OwnPtr(const OwnPtr<U>&) = delete;
OwnPtr& operator=(const OwnPtr&) = delete;
template<typename U>
OwnPtr& operator=(const OwnPtr<U>&) = delete;
template<typename U>
OwnPtr(const NonnullOwnPtr<U>&) = delete;
template<typename U>
OwnPtr& operator=(const NonnullOwnPtr<U>&) = delete;
template<typename U>
OwnPtr(const RefPtr<U>&) = delete;
template<typename U>
OwnPtr(const NonnullRefPtr<U>&) = delete;
template<typename U>
OwnPtr(const WeakPtr<U>&) = delete;
template<typename U>
OwnPtr& operator=(const RefPtr<U>&) = delete;
template<typename U>
OwnPtr& operator=(const NonnullRefPtr<U>&) = delete;
template<typename U>
OwnPtr& operator=(const WeakPtr<U>&) = delete;
OwnPtr& operator=(OwnPtr&& other)
{
OwnPtr ptr(move(other));
swap(ptr);
return *this;
}
template<typename U>
OwnPtr& operator=(OwnPtr<U>&& other)
{
OwnPtr ptr(move(other));
swap(ptr);
return *this;
}
template<typename U>
OwnPtr& operator=(NonnullOwnPtr<U>&& other)
{
OwnPtr ptr(move(other));
swap(ptr);
VERIFY(m_ptr);
return *this;
}
OwnPtr& operator=(T* ptr) = delete;
OwnPtr& operator=(std::nullptr_t)
{
clear();
return *this;
}
void clear()
{
delete m_ptr;
m_ptr = nullptr;
}
bool operator!() const { return !m_ptr; }
[[nodiscard]] T* leak_ptr()
{
T* leaked_ptr = m_ptr;
m_ptr = nullptr;
return leaked_ptr;
}
NonnullOwnPtr<T> release_nonnull()
{
VERIFY(m_ptr);
return NonnullOwnPtr<T>(NonnullOwnPtr<T>::Adopt, *leak_ptr());
}
template<typename U>
NonnullOwnPtr<U> release_nonnull()
{
VERIFY(m_ptr);
return NonnullOwnPtr<U>(NonnullOwnPtr<U>::Adopt, static_cast<U&>(*leak_ptr()));
}
T* ptr() { return m_ptr; }
const T* ptr() const { return m_ptr; }
T* operator->()
{
VERIFY(m_ptr);
return m_ptr;
}
const T* operator->() const
{
VERIFY(m_ptr);
return m_ptr;
}
T& operator*()
{
VERIFY(m_ptr);
return *m_ptr;
}
const T& operator*() const
{
VERIFY(m_ptr);
return *m_ptr;
}
operator const T*() const { return m_ptr; }
operator T*() { return m_ptr; }
operator bool() { return !!m_ptr; }
void swap(OwnPtr& other)
{
::swap(m_ptr, other.m_ptr);
}
template<typename U>
void swap(OwnPtr<U>& other)
{
::swap(m_ptr, other.m_ptr);
}
static OwnPtr lift(T* ptr)
{
return OwnPtr { ptr };
}
protected:
explicit OwnPtr(T* ptr)
: m_ptr(ptr)
{
static_assert(
requires { requires typename T::AllowOwnPtr()(); } || !requires { requires !typename T::AllowOwnPtr()(); declval<T>().ref(); declval<T>().unref(); }, "Use RefPtr<> for RefCounted types");
}
private:
T* m_ptr = nullptr;
};
template<typename T, typename U>
inline void swap(OwnPtr<T>& a, OwnPtr<U>& b)
{
a.swap(b);
}
template<typename T>
inline OwnPtr<T> adopt_own_if_nonnull(T* object)
{
if (object)
return OwnPtr<T>::lift(object);
return {};
}
template<typename T, class... Args>
requires(IsConstructible<T, Args...>) inline OwnPtr<T> try_make(Args&&... args)
{
return adopt_own_if_nonnull(new (nothrow) T(forward<Args>(args)...));
}
// FIXME: Remove once P0960R3 is available in Clang.
template<typename T, class... Args>
inline OwnPtr<T> try_make(Args&&... args)
{
return adopt_own_if_nonnull(new (nothrow) T { forward<Args>(args)... });
}
template<typename T>
struct Traits<OwnPtr<T>> : public GenericTraits<OwnPtr<T>> {
using PeekType = T*;
using ConstPeekType = const T*;
static unsigned hash(const OwnPtr<T>& p) { return ptr_hash(p.ptr()); }
static bool equals(const OwnPtr<T>& a, const OwnPtr<T>& b) { return a.ptr() == b.ptr(); }
};
}
using AK::adopt_own_if_nonnull;
using AK::OwnPtr;
using AK::try_make;