ladybird/AK/OwnPtr.h
Lenny Maiorani e6f907a155 AK: Simplify constructors and conversions from nullptr_t
Problem:
- Many constructors are defined as `{}` rather than using the ` =
  default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
  instead of requiring the caller to default construct. This violates
  the C++ Core Guidelines suggestion to declare single-argument
  constructors explicit
  (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).

Solution:
- Change default constructors to use the compiler-provided default
  constructor.
- Remove implicit conversion operators from `nullptr_t` and change
  usage to enforce type consistency without conversion.
2021-01-12 09:11:45 +01:00

230 lines
5.6 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/NonnullOwnPtr.h>
#include <AK/RefCounted.h>
namespace AK {
template<typename T>
class OwnPtr {
public:
OwnPtr() = default;
explicit OwnPtr(T* ptr)
: m_ptr(ptr)
{
static_assert(
requires { requires typename T::AllowOwnPtr()(); } || !requires(T obj) { requires !typename T::AllowOwnPtr()(); obj.ref(); obj.unref(); },
"Use RefPtr<> for RefCounted types");
}
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);
ASSERT(m_ptr);
return *this;
}
OwnPtr& operator=(T* ptr)
{
if (m_ptr != ptr)
delete m_ptr;
m_ptr = ptr;
return *this;
}
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()
{
ASSERT(m_ptr);
return NonnullOwnPtr<T>(NonnullOwnPtr<T>::Adopt, *leak_ptr());
}
template<typename U>
NonnullOwnPtr<U> release_nonnull()
{
ASSERT(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->()
{
ASSERT(m_ptr);
return m_ptr;
}
const T* operator->() const
{
ASSERT(m_ptr);
return m_ptr;
}
T& operator*()
{
ASSERT(m_ptr);
return *m_ptr;
}
const T& operator*() const
{
ASSERT(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);
}
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>
struct Traits<OwnPtr<T>> : public GenericTraits<OwnPtr<T>> {
using PeekType = 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(); }
};
template<typename T>
inline const LogStream& operator<<(const LogStream& stream, const OwnPtr<T>& value)
{
return stream << value.ptr();
}
}
using AK::OwnPtr;