ladybird/AK/RefPtr.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

368 lines
8.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#define REFPTR_SCRUB_BYTE 0xe0
#ifdef KERNEL
# include <Kernel/Library/ThreadSafeRefPtr.h>
#else
# include <AK/Assertions.h>
# include <AK/Atomic.h>
# include <AK/Error.h>
# include <AK/Format.h>
# include <AK/NonnullRefPtr.h>
# include <AK/StdLibExtras.h>
# include <AK/Traits.h>
# include <AK/Types.h>
namespace AK {
template<typename T>
class OwnPtr;
template<typename T, typename PtrTraits>
class [[nodiscard]] RefPtr {
template<typename U, typename P>
friend class RefPtr;
template<typename U>
friend class WeakPtr;
public:
enum AdoptTag {
Adopt
};
RefPtr() = default;
RefPtr(T const* ptr)
: m_ptr(const_cast<T*>(ptr))
{
ref_if_not_null(m_ptr);
}
RefPtr(T const& object)
: m_ptr(const_cast<T*>(&object))
{
m_ptr->ref();
}
RefPtr(AdoptTag, T& object)
: m_ptr(&object)
{
}
RefPtr(RefPtr&& other)
: m_ptr(other.leak_ref())
{
}
ALWAYS_INLINE RefPtr(NonnullRefPtr<T> const& other)
: m_ptr(const_cast<T*>(other.ptr()))
{
m_ptr->ref();
}
template<typename U>
ALWAYS_INLINE RefPtr(NonnullRefPtr<U> const& other) requires(IsConvertible<U*, T*>)
: m_ptr(const_cast<T*>(static_cast<T const*>(other.ptr())))
{
m_ptr->ref();
}
template<typename U>
ALWAYS_INLINE RefPtr(NonnullRefPtr<U>&& other) requires(IsConvertible<U*, T*>)
: m_ptr(static_cast<T*>(&other.leak_ref()))
{
}
template<typename U, typename P = RefPtrTraits<U>>
RefPtr(RefPtr<U, P>&& other) requires(IsConvertible<U*, T*>)
: m_ptr(static_cast<T*>(other.leak_ref()))
{
}
RefPtr(RefPtr const& other)
: m_ptr(other.m_ptr)
{
ref_if_not_null(m_ptr);
}
template<typename U, typename P = RefPtrTraits<U>>
RefPtr(RefPtr<U, P> const& other) requires(IsConvertible<U*, T*>)
: m_ptr(const_cast<T*>(static_cast<T const*>(other.ptr())))
{
ref_if_not_null(m_ptr);
}
ALWAYS_INLINE ~RefPtr()
{
clear();
# ifdef SANITIZE_PTRS
m_ptr = reinterpret_cast<T*>(explode_byte(REFPTR_SCRUB_BYTE));
# endif
}
template<typename U>
RefPtr(OwnPtr<U> const&) = delete;
template<typename U>
RefPtr& operator=(OwnPtr<U> const&) = delete;
void swap(RefPtr& other)
{
AK::swap(m_ptr, other.m_ptr);
}
template<typename U, typename P = RefPtrTraits<U>>
void swap(RefPtr<U, P>& other) requires(IsConvertible<U*, T*>)
{
AK::swap(m_ptr, other.m_ptr);
}
ALWAYS_INLINE RefPtr& operator=(RefPtr&& other)
{
RefPtr tmp { move(other) };
swap(tmp);
return *this;
}
template<typename U, typename P = RefPtrTraits<U>>
ALWAYS_INLINE RefPtr& operator=(RefPtr<U, P>&& other) requires(IsConvertible<U*, T*>)
{
RefPtr tmp { move(other) };
swap(tmp);
return *this;
}
template<typename U>
ALWAYS_INLINE RefPtr& operator=(NonnullRefPtr<U>&& other) requires(IsConvertible<U*, T*>)
{
RefPtr tmp { move(other) };
swap(tmp);
return *this;
}
ALWAYS_INLINE RefPtr& operator=(NonnullRefPtr<T> const& other)
{
RefPtr tmp { other };
swap(tmp);
return *this;
}
template<typename U>
ALWAYS_INLINE RefPtr& operator=(NonnullRefPtr<U> const& other) requires(IsConvertible<U*, T*>)
{
RefPtr tmp { other };
swap(tmp);
return *this;
}
ALWAYS_INLINE RefPtr& operator=(RefPtr const& other)
{
RefPtr tmp { other };
swap(tmp);
return *this;
}
template<typename U>
ALWAYS_INLINE RefPtr& operator=(RefPtr<U> const& other) requires(IsConvertible<U*, T*>)
{
RefPtr tmp { other };
swap(tmp);
return *this;
}
ALWAYS_INLINE RefPtr& operator=(T const* ptr)
{
RefPtr tmp { ptr };
swap(tmp);
return *this;
}
ALWAYS_INLINE RefPtr& operator=(T const& object)
{
RefPtr tmp { object };
swap(tmp);
return *this;
}
RefPtr& operator=(std::nullptr_t)
{
clear();
return *this;
}
ALWAYS_INLINE bool assign_if_null(RefPtr&& other)
{
if (this == &other)
return is_null();
*this = move(other);
return true;
}
template<typename U, typename P = RefPtrTraits<U>>
ALWAYS_INLINE bool assign_if_null(RefPtr<U, P>&& other)
{
if (this == &other)
return is_null();
*this = move(other);
return true;
}
ALWAYS_INLINE void clear()
{
unref_if_not_null(m_ptr);
m_ptr = nullptr;
}
bool operator!() const { return !m_ptr; }
[[nodiscard]] T* leak_ref()
{
return exchange(m_ptr, nullptr);
}
NonnullRefPtr<T> release_nonnull()
{
auto* ptr = leak_ref();
VERIFY(ptr);
return NonnullRefPtr<T>(NonnullRefPtr<T>::Adopt, *ptr);
}
ALWAYS_INLINE T* ptr() { return as_ptr(); }
ALWAYS_INLINE const T* ptr() const { return as_ptr(); }
ALWAYS_INLINE T* operator->()
{
return as_nonnull_ptr();
}
ALWAYS_INLINE 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 operator const T*() const { return as_ptr(); }
ALWAYS_INLINE operator T*() { return as_ptr(); }
ALWAYS_INLINE operator bool() { return !is_null(); }
bool operator==(std::nullptr_t) const { return is_null(); }
bool operator!=(std::nullptr_t) const { return !is_null(); }
bool operator==(const RefPtr& other) const { return as_ptr() == other.as_ptr(); }
bool operator!=(const RefPtr& other) const { return as_ptr() != other.as_ptr(); }
bool operator==(RefPtr& other) { return as_ptr() == other.as_ptr(); }
bool operator!=(RefPtr& other) { return as_ptr() != other.as_ptr(); }
bool operator==(const T* other) const { return as_ptr() == other; }
bool operator!=(const T* other) const { return as_ptr() != other; }
bool operator==(T* other) { return as_ptr() == other; }
bool operator!=(T* other) { return as_ptr() != other; }
ALWAYS_INLINE bool is_null() const { return !m_ptr; }
private:
ALWAYS_INLINE T* as_ptr() const
{
return m_ptr;
}
ALWAYS_INLINE T* as_nonnull_ptr() const
{
VERIFY(m_ptr);
return m_ptr;
}
T* m_ptr { nullptr };
};
template<typename T>
struct Formatter<RefPtr<T>> : Formatter<const T*> {
ErrorOr<void> format(FormatBuilder& builder, RefPtr<T> const& value)
{
return Formatter<const T*>::format(builder, value.ptr());
}
};
template<typename T>
struct Traits<RefPtr<T>> : public GenericTraits<RefPtr<T>> {
using PeekType = T*;
using ConstPeekType = const T*;
static unsigned hash(const RefPtr<T>& p) { return ptr_hash(p.ptr()); }
static bool equals(const RefPtr<T>& a, const RefPtr<T>& b) { return a.ptr() == b.ptr(); }
};
template<typename T, typename U>
inline NonnullRefPtr<T> static_ptr_cast(const NonnullRefPtr<U>& ptr)
{
return NonnullRefPtr<T>(static_cast<const T&>(*ptr));
}
template<typename T, typename U, typename PtrTraits = RefPtrTraits<T>>
inline RefPtr<T> static_ptr_cast(const RefPtr<U>& ptr)
{
return RefPtr<T, PtrTraits>(static_cast<const T*>(ptr.ptr()));
}
template<typename T, typename PtrTraitsT, typename U, typename PtrTraitsU>
inline void swap(RefPtr<T, PtrTraitsT>& a, RefPtr<U, PtrTraitsU>& b) requires(IsConvertible<U*, T*>)
{
a.swap(b);
}
template<typename T>
inline RefPtr<T> adopt_ref_if_nonnull(T* object)
{
if (object)
return RefPtr<T>(RefPtr<T>::Adopt, *object);
return {};
}
template<typename T, class... Args>
requires(IsConstructible<T, Args...>) inline RefPtr<T> try_make_ref_counted(Args&&... args)
{
return adopt_ref_if_nonnull(new (nothrow) T(forward<Args>(args)...));
}
// FIXME: Remove once P0960R3 is available in Clang.
template<typename T, class... Args>
inline RefPtr<T> try_make_ref_counted(Args&&... args)
{
return adopt_ref_if_nonnull(new (nothrow) T { forward<Args>(args)... });
}
template<typename T>
inline ErrorOr<NonnullRefPtr<T>> adopt_nonnull_ref_or_enomem(T* object)
{
auto result = adopt_ref_if_nonnull(object);
if (!result)
return Error::from_errno(ENOMEM);
return result.release_nonnull();
}
}
using AK::adopt_ref_if_nonnull;
using AK::RefPtr;
using AK::static_ptr_cast;
using AK::try_make_ref_counted;
#endif