ladybird/AK/NonnullOwnPtr.h
AnotherTest 060ddd2a7a AK: Really disallow making OwnPtrs from refcounted types
This looks at three things:
- if the type has a typedef `AllowOwnPtr', respect that
- if not, disallow construction if both of `ref()' and `unref()' are
  present.
Note that in the second case, if a type only defines `ref()' or only
defines `unref()', an OwnPtr can be created, as a RefPtr of that type
would be ill-formed.

Also marks a `Performance' to explicitly allow OwnPtrs.
2020-11-03 19:14:34 +01:00

210 lines
5.8 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/Assertions.h>
#include <AK/LogStream.h>
#include <AK/RefCounted.h>
#include <AK/StdLibExtras.h>
#include <AK/Traits.h>
#include <AK/Types.h>
namespace AK {
template<typename T>
class RefPtr;
template<typename T>
class NonnullRefPtr;
template<typename T>
class WeakPtr;
template<typename T>
class NonnullOwnPtr {
public:
typedef T ElementType;
enum AdoptTag { Adopt };
NonnullOwnPtr(AdoptTag, T& ptr)
: m_ptr(&ptr)
{
static_assert(
requires { requires typename T::AllowOwnPtr()(); } || !requires(T obj) { requires !typename T::AllowOwnPtr()(); obj.ref(); obj.unref(); },
"Use NonnullRefPtr<> for RefCounted types");
}
NonnullOwnPtr(NonnullOwnPtr&& other)
: m_ptr(other.leak_ptr())
{
ASSERT(m_ptr);
}
template<typename U>
NonnullOwnPtr(NonnullOwnPtr<U>&& other)
: m_ptr(other.leak_ptr())
{
ASSERT(m_ptr);
}
~NonnullOwnPtr()
{
clear();
#ifdef SANITIZE_PTRS
if constexpr (sizeof(T*) == 8)
m_ptr = (T*)(0xe3e3e3e3e3e3e3e3);
else
m_ptr = (T*)(0xe3e3e3e3);
#endif
}
NonnullOwnPtr(const NonnullOwnPtr&) = delete;
template<typename U>
NonnullOwnPtr(const NonnullOwnPtr<U>&) = delete;
NonnullOwnPtr& operator=(const NonnullOwnPtr&) = delete;
template<typename U>
NonnullOwnPtr& operator=(const NonnullOwnPtr<U>&) = delete;
template<typename U>
NonnullOwnPtr(const RefPtr<U>&) = delete;
template<typename U>
NonnullOwnPtr(const NonnullRefPtr<U>&) = delete;
template<typename U>
NonnullOwnPtr(const WeakPtr<U>&) = delete;
template<typename U>
NonnullOwnPtr& operator=(const RefPtr<U>&) = delete;
template<typename U>
NonnullOwnPtr& operator=(const NonnullRefPtr<U>&) = delete;
template<typename U>
NonnullOwnPtr& operator=(const WeakPtr<U>&) = delete;
NonnullOwnPtr& operator=(NonnullOwnPtr&& other)
{
NonnullOwnPtr ptr(move(other));
swap(ptr);
return *this;
}
template<typename U>
NonnullOwnPtr& operator=(NonnullOwnPtr<U>&& other)
{
NonnullOwnPtr ptr(move(other));
swap(ptr);
return *this;
}
[[nodiscard]] T* leak_ptr()
{
return exchange(m_ptr, nullptr);
}
T* ptr() { return m_ptr; }
const T* ptr() const { return m_ptr; }
T* operator->() { return m_ptr; }
const T* operator->() const { return m_ptr; }
T& operator*() { return *m_ptr; }
const T& operator*() const { return *m_ptr; }
operator const T*() const { return m_ptr; }
operator T*() { return m_ptr; }
operator bool() const = delete;
bool operator!() const = delete;
void swap(NonnullOwnPtr& other)
{
::swap(m_ptr, other.m_ptr);
}
template<typename U>
void swap(NonnullOwnPtr<U>& other)
{
::swap(m_ptr, other.m_ptr);
}
template<typename U>
NonnullOwnPtr<U> release_nonnull()
{
ASSERT(m_ptr);
return NonnullOwnPtr<U>(NonnullOwnPtr<U>::Adopt, static_cast<U&>(*leak_ptr()));
}
private:
void clear()
{
if (!m_ptr)
return;
delete m_ptr;
m_ptr = nullptr;
}
T* m_ptr = nullptr;
};
template<typename T>
inline NonnullOwnPtr<T> adopt_own(T& object)
{
return NonnullOwnPtr<T>(NonnullOwnPtr<T>::Adopt, object);
}
template<class T, class... Args>
inline NonnullOwnPtr<T>
make(Args&&... args)
{
return NonnullOwnPtr<T>(NonnullOwnPtr<T>::Adopt, *new T(forward<Args>(args)...));
}
template<typename T>
struct Traits<NonnullOwnPtr<T>> : public GenericTraits<NonnullOwnPtr<T>> {
using PeekType = const T*;
static unsigned hash(const NonnullOwnPtr<T>& p) { return int_hash((u32)p.ptr()); }
static bool equals(const NonnullOwnPtr<T>& a, const NonnullOwnPtr<T>& b) { return a.ptr() == b.ptr(); }
};
template<typename T>
inline const LogStream& operator<<(const LogStream& stream, const NonnullOwnPtr<T>& value)
{
return stream << value.ptr();
}
template<typename T, typename U>
inline void swap(NonnullOwnPtr<T>& a, NonnullOwnPtr<U>& b)
{
a.swap(b);
}
template<typename T>
struct Formatter<NonnullOwnPtr<T>> : Formatter<const T*> {
void format(TypeErasedFormatParams& params, FormatBuilder& builder, const NonnullOwnPtr<T>& value)
{
Formatter<const T*>::format(params, builder, value.ptr());
}
};
}
using AK::adopt_own;
using AK::make;
using AK::NonnullOwnPtr;