ladybird/AK/NonnullRefPtr.h
Sam Atkins 5013a6480d AK: Mark smart pointer classes as [[nodiscard]]
This makes it an error to not do something with a returned smart
pointer, which should help prevent mistakes. In cases where you do need
to ignore the value, casting to void will placate the compiler.

I did have to add comments to disable clang-format on a couple of lines,
where it wanted to format the code like this:

```c++
private : NonnullRefPtr() = delete;
```
2021-12-05 15:31:03 +01:00

282 lines
6.4 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#define NONNULLREFPTR_SCRUB_BYTE 0xe1
#ifdef KERNEL
# include <Kernel/Library/ThreadSafeNonnullRefPtr.h>
#else
# include <AK/Assertions.h>
# include <AK/Atomic.h>
# include <AK/Format.h>
# include <AK/Traits.h>
# include <AK/Types.h>
namespace AK {
template<typename T>
class OwnPtr;
template<typename T, typename PtrTraits>
class RefPtr;
template<typename T>
ALWAYS_INLINE void ref_if_not_null(T* ptr)
{
if (ptr)
ptr->ref();
}
template<typename T>
ALWAYS_INLINE void unref_if_not_null(T* ptr)
{
if (ptr)
ptr->unref();
}
template<typename T>
class [[nodiscard]] NonnullRefPtr {
template<typename U, typename P>
friend class RefPtr;
template<typename U>
friend class NonnullRefPtr;
template<typename U>
friend class WeakPtr;
public:
using ElementType = T;
enum AdoptTag { Adopt };
ALWAYS_INLINE NonnullRefPtr(T const& object)
: m_ptr(const_cast<T*>(&object))
{
m_ptr->ref();
}
template<typename U>
ALWAYS_INLINE NonnullRefPtr(U const& object) requires(IsConvertible<U*, T*>)
: m_ptr(const_cast<T*>(static_cast<T const*>(&object)))
{
m_ptr->ref();
}
ALWAYS_INLINE NonnullRefPtr(AdoptTag, T& object)
: m_ptr(&object)
{
}
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr&& other)
: m_ptr(&other.leak_ref())
{
}
template<typename U>
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr<U>&& other) requires(IsConvertible<U*, T*>)
: m_ptr(static_cast<T*>(&other.leak_ref()))
{
}
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr const& other)
: m_ptr(const_cast<T*>(other.ptr()))
{
m_ptr->ref();
}
template<typename U>
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr<U> const& other) requires(IsConvertible<U*, T*>)
: m_ptr(const_cast<T*>(static_cast<T const*>(other.ptr())))
{
m_ptr->ref();
}
ALWAYS_INLINE ~NonnullRefPtr()
{
unref_if_not_null(m_ptr);
m_ptr = nullptr;
# ifdef SANITIZE_PTRS
m_ptr = reinterpret_cast<T*>(explode_byte(NONNULLREFPTR_SCRUB_BYTE));
# endif
}
template<typename U>
NonnullRefPtr(const OwnPtr<U>&) = delete;
template<typename U>
NonnullRefPtr& operator=(const OwnPtr<U>&) = delete;
template<typename U>
NonnullRefPtr(const RefPtr<U>&) = delete;
template<typename U>
NonnullRefPtr& operator=(const RefPtr<U>&) = delete;
NonnullRefPtr(const RefPtr<T>&) = delete;
NonnullRefPtr& operator=(const RefPtr<T>&) = delete;
NonnullRefPtr& operator=(NonnullRefPtr const& other)
{
NonnullRefPtr tmp { other };
swap(tmp);
return *this;
}
template<typename U>
NonnullRefPtr& operator=(NonnullRefPtr<U> const& other) requires(IsConvertible<U*, T*>)
{
NonnullRefPtr tmp { other };
swap(tmp);
return *this;
}
ALWAYS_INLINE NonnullRefPtr& operator=(NonnullRefPtr&& other)
{
NonnullRefPtr tmp { move(other) };
swap(tmp);
return *this;
}
template<typename U>
NonnullRefPtr& operator=(NonnullRefPtr<U>&& other) requires(IsConvertible<U*, T*>)
{
NonnullRefPtr tmp { move(other) };
swap(tmp);
return *this;
}
NonnullRefPtr& operator=(T const& object)
{
NonnullRefPtr tmp { object };
swap(tmp);
return *this;
}
[[nodiscard]] ALWAYS_INLINE T& leak_ref()
{
T* ptr = exchange(m_ptr, nullptr);
VERIFY(ptr);
return *ptr;
}
ALWAYS_INLINE RETURNS_NONNULL T* ptr()
{
return as_nonnull_ptr();
}
ALWAYS_INLINE RETURNS_NONNULL const T* ptr() const
{
return as_nonnull_ptr();
}
ALWAYS_INLINE RETURNS_NONNULL T* operator->()
{
return as_nonnull_ptr();
}
ALWAYS_INLINE RETURNS_NONNULL const T* operator->() const
{
return as_nonnull_ptr();
}
ALWAYS_INLINE T& operator*()
{
return *as_nonnull_ptr();
}
ALWAYS_INLINE const T& operator*() const
{
return *as_nonnull_ptr();
}
ALWAYS_INLINE RETURNS_NONNULL operator T*()
{
return as_nonnull_ptr();
}
ALWAYS_INLINE RETURNS_NONNULL operator const T*() const
{
return as_nonnull_ptr();
}
ALWAYS_INLINE operator T&()
{
return *as_nonnull_ptr();
}
ALWAYS_INLINE operator const T&() const
{
return *as_nonnull_ptr();
}
operator bool() const = delete;
bool operator!() const = delete;
void swap(NonnullRefPtr& other)
{
AK::swap(m_ptr, other.m_ptr);
}
template<typename U>
void swap(NonnullRefPtr<U>& other) requires(IsConvertible<U*, T*>)
{
AK::swap(m_ptr, other.m_ptr);
}
// clang-format off
private:
NonnullRefPtr() = delete;
// clang-format on
ALWAYS_INLINE RETURNS_NONNULL T* as_nonnull_ptr() const
{
VERIFY(m_ptr);
return m_ptr;
}
T* m_ptr { nullptr };
};
template<typename T>
inline NonnullRefPtr<T> adopt_ref(T& object)
{
return NonnullRefPtr<T>(NonnullRefPtr<T>::Adopt, object);
}
template<typename T>
struct Formatter<NonnullRefPtr<T>> : Formatter<const T*> {
ErrorOr<void> format(FormatBuilder& builder, NonnullRefPtr<T> const& value)
{
return Formatter<const T*>::format(builder, value.ptr());
}
};
template<typename T, typename U>
inline void swap(NonnullRefPtr<T>& a, NonnullRefPtr<U>& b) requires(IsConvertible<U*, T*>)
{
a.swap(b);
}
template<typename T, class... Args>
requires(IsConstructible<T, Args...>) inline NonnullRefPtr<T> make_ref_counted(Args&&... args)
{
return NonnullRefPtr<T>(NonnullRefPtr<T>::Adopt, *new T(forward<Args>(args)...));
}
// FIXME: Remove once P0960R3 is available in Clang.
template<typename T, class... Args>
inline NonnullRefPtr<T> make_ref_counted(Args&&... args)
{
return NonnullRefPtr<T>(NonnullRefPtr<T>::Adopt, *new T { forward<Args>(args)... });
}
}
template<typename T>
struct Traits<NonnullRefPtr<T>> : public GenericTraits<NonnullRefPtr<T>> {
using PeekType = T*;
using ConstPeekType = const T*;
static unsigned hash(const NonnullRefPtr<T>& p) { return ptr_hash(p.ptr()); }
static bool equals(const NonnullRefPtr<T>& a, const NonnullRefPtr<T>& b) { return a.ptr() == b.ptr(); }
};
using AK::adopt_ref;
using AK::make_ref_counted;
using AK::NonnullRefPtr;
#endif