ladybird/AK/OwnPtr.h
Luke Wilde 49259777ef Kernel: Note if the page fault address is a destroyed smart pointer
While I was working on LibWeb, I got a page fault at 0xe0e0e0e4.
This indicates a destroyed RefPtr if compiled with SANITIZE_PTRS
defined. However, the page fault handler didn't print out this
indication.

This makes the page fault handler print out a note if the faulting
address looks like a recently destroyed RefPtr, OwnPtr, NonnullRefPtr,
NonnullOwnPtr, ThreadSafeRefPtr or ThreadSafeNonnullRefPtr. It will
only do this if SANITIZE_PTRS is defined, as smart pointers don't get
scrubbed without it being defined.
2021-10-07 21:30:13 +02:00

252 lines
5.2 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>
#ifdef KERNEL
# include <Kernel/API/KResult.h>
#endif
#define OWNPTR_SCRUB_BYTE 0xf0
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
m_ptr = (T*)(explode_byte(OWNPTR_SCRUB_BYTE));
#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 {};
}
#ifdef KERNEL
template<typename T>
inline Kernel::KResultOr<NonnullOwnPtr<T>> adopt_nonnull_own_or_enomem(T* object)
{
auto result = adopt_own_if_nonnull(object);
if (!result)
return ENOMEM;
return result.release_nonnull();
}
#endif
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;
#ifdef KERNEL
using AK::adopt_nonnull_own_or_enomem;
#endif