mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 21:02:44 +00:00
350 lines
8.8 KiB
C++
350 lines
8.8 KiB
C++
/*
|
|
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Assertions.h>
|
|
#include <AK/Atomic.h>
|
|
#include <AK/Format.h>
|
|
#include <AK/Traits.h>
|
|
#include <AK/Types.h>
|
|
#ifdef KERNEL
|
|
# include <Kernel/Arch/Processor.h>
|
|
# include <Kernel/Arch/ScopedCritical.h>
|
|
#endif
|
|
|
|
#define THREADSAFENONNULLREFPTR_SCRUB_BYTE 0xa1
|
|
|
|
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(const T& object)
|
|
: m_bits((FlatPtr)&object)
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
const_cast<T&>(object).ref();
|
|
}
|
|
template<typename U>
|
|
ALWAYS_INLINE NonnullRefPtr(const U& object) requires(IsConvertible<U*, T*>)
|
|
: m_bits((FlatPtr) static_cast<const T*>(&object))
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
const_cast<T&>(static_cast<const T&>(object)).ref();
|
|
}
|
|
ALWAYS_INLINE NonnullRefPtr(AdoptTag, T& object)
|
|
: m_bits((FlatPtr)&object)
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
}
|
|
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr&& other)
|
|
: m_bits((FlatPtr)&other.leak_ref())
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
}
|
|
template<typename U>
|
|
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr<U>&& other) requires(IsConvertible<U*, T*>)
|
|
: m_bits((FlatPtr)&other.leak_ref())
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
}
|
|
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr const& other)
|
|
: m_bits((FlatPtr)other.add_ref())
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
}
|
|
template<typename U>
|
|
ALWAYS_INLINE NonnullRefPtr(NonnullRefPtr<U> const& other) requires(IsConvertible<U*, T*>)
|
|
: m_bits((FlatPtr)other.add_ref())
|
|
{
|
|
VERIFY(!(m_bits & 1));
|
|
}
|
|
ALWAYS_INLINE ~NonnullRefPtr()
|
|
{
|
|
assign(nullptr);
|
|
#ifdef SANITIZE_PTRS
|
|
m_bits.store(explode_byte(THREADSAFENONNULLREFPTR_SCRUB_BYTE), AK::MemoryOrder::memory_order_relaxed);
|
|
#endif
|
|
}
|
|
|
|
template<typename U>
|
|
NonnullRefPtr(OwnPtr<U> const&) = delete;
|
|
template<typename U>
|
|
NonnullRefPtr& operator=(OwnPtr<U> const&) = delete;
|
|
|
|
template<typename U>
|
|
NonnullRefPtr(RefPtr<U> const&) = delete;
|
|
template<typename U>
|
|
NonnullRefPtr& operator=(RefPtr<U> const&) = delete;
|
|
NonnullRefPtr(RefPtr<T> const&) = delete;
|
|
NonnullRefPtr& operator=(RefPtr<T> const&) = delete;
|
|
|
|
NonnullRefPtr& operator=(NonnullRefPtr const& other)
|
|
{
|
|
if (this != &other)
|
|
assign(other.add_ref());
|
|
return *this;
|
|
}
|
|
|
|
template<typename U>
|
|
NonnullRefPtr& operator=(NonnullRefPtr<U> const& other) requires(IsConvertible<U*, T*>)
|
|
{
|
|
assign(other.add_ref());
|
|
return *this;
|
|
}
|
|
|
|
ALWAYS_INLINE NonnullRefPtr& operator=(NonnullRefPtr&& other)
|
|
{
|
|
if (this != &other)
|
|
assign(&other.leak_ref());
|
|
return *this;
|
|
}
|
|
|
|
template<typename U>
|
|
NonnullRefPtr& operator=(NonnullRefPtr<U>&& other) requires(IsConvertible<U*, T*>)
|
|
{
|
|
assign(&other.leak_ref());
|
|
return *this;
|
|
}
|
|
|
|
NonnullRefPtr& operator=(const T& object)
|
|
{
|
|
const_cast<T&>(object).ref();
|
|
assign(const_cast<T*>(&object));
|
|
return *this;
|
|
}
|
|
|
|
[[nodiscard]] ALWAYS_INLINE T& leak_ref()
|
|
{
|
|
T* ptr = exchange(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)
|
|
{
|
|
if (this == &other)
|
|
return;
|
|
|
|
// NOTE: swap is not atomic!
|
|
T* other_ptr = other.exchange(nullptr);
|
|
T* ptr = exchange(other_ptr);
|
|
other.exchange(ptr);
|
|
}
|
|
|
|
template<typename U>
|
|
void swap(NonnullRefPtr<U>& other) requires(IsConvertible<U*, T*>)
|
|
{
|
|
// NOTE: swap is not atomic!
|
|
U* other_ptr = other.exchange(nullptr);
|
|
T* ptr = exchange(other_ptr);
|
|
other.exchange(ptr);
|
|
}
|
|
|
|
// clang-format off
|
|
private:
|
|
NonnullRefPtr() = delete;
|
|
// clang-format on
|
|
|
|
ALWAYS_INLINE T* as_ptr() const
|
|
{
|
|
return (T*)(m_bits.load(AK::MemoryOrder::memory_order_relaxed) & ~(FlatPtr)1);
|
|
}
|
|
|
|
ALWAYS_INLINE RETURNS_NONNULL T* as_nonnull_ptr() const
|
|
{
|
|
T* ptr = (T*)(m_bits.load(AK::MemoryOrder::memory_order_relaxed) & ~(FlatPtr)1);
|
|
VERIFY(ptr);
|
|
return ptr;
|
|
}
|
|
|
|
template<typename F>
|
|
void do_while_locked(F f) const
|
|
{
|
|
#ifdef KERNEL
|
|
// We don't want to be pre-empted while we have the lock bit set
|
|
Kernel::ScopedCritical critical;
|
|
#endif
|
|
FlatPtr bits;
|
|
for (;;) {
|
|
bits = m_bits.fetch_or(1, AK::MemoryOrder::memory_order_acq_rel);
|
|
if (!(bits & 1))
|
|
break;
|
|
#ifdef KERNEL
|
|
Kernel::Processor::wait_check();
|
|
#endif
|
|
}
|
|
VERIFY(!(bits & 1));
|
|
f((T*)bits);
|
|
m_bits.store(bits, AK::MemoryOrder::memory_order_release);
|
|
}
|
|
|
|
ALWAYS_INLINE void assign(T* new_ptr)
|
|
{
|
|
T* prev_ptr = exchange(new_ptr);
|
|
unref_if_not_null(prev_ptr);
|
|
}
|
|
|
|
ALWAYS_INLINE T* exchange(T* new_ptr)
|
|
{
|
|
VERIFY(!((FlatPtr)new_ptr & 1));
|
|
#ifdef KERNEL
|
|
// We don't want to be pre-empted while we have the lock bit set
|
|
Kernel::ScopedCritical critical;
|
|
#endif
|
|
// Only exchange while not locked
|
|
FlatPtr expected = m_bits.load(AK::MemoryOrder::memory_order_relaxed);
|
|
for (;;) {
|
|
expected &= ~(FlatPtr)1; // only if lock bit is not set
|
|
if (m_bits.compare_exchange_strong(expected, (FlatPtr)new_ptr, AK::MemoryOrder::memory_order_acq_rel))
|
|
break;
|
|
#ifdef KERNEL
|
|
Kernel::Processor::wait_check();
|
|
#endif
|
|
}
|
|
VERIFY(!(expected & 1));
|
|
return (T*)expected;
|
|
}
|
|
|
|
T* add_ref() const
|
|
{
|
|
#ifdef KERNEL
|
|
// We don't want to be pre-empted while we have the lock bit set
|
|
Kernel::ScopedCritical critical;
|
|
#endif
|
|
// Lock the pointer
|
|
FlatPtr expected = m_bits.load(AK::MemoryOrder::memory_order_relaxed);
|
|
for (;;) {
|
|
expected &= ~(FlatPtr)1; // only if lock bit is not set
|
|
if (m_bits.compare_exchange_strong(expected, expected | 1, AK::MemoryOrder::memory_order_acq_rel))
|
|
break;
|
|
#ifdef KERNEL
|
|
Kernel::Processor::wait_check();
|
|
#endif
|
|
}
|
|
|
|
// Add a reference now that we locked the pointer
|
|
ref_if_not_null((T*)expected);
|
|
|
|
// Unlock the pointer again
|
|
m_bits.store(expected, AK::MemoryOrder::memory_order_release);
|
|
return (T*)expected;
|
|
}
|
|
|
|
mutable Atomic<FlatPtr> m_bits { 0 };
|
|
};
|
|
|
|
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>
|
|
struct Traits<NonnullRefPtr<T>> : public GenericTraits<NonnullRefPtr<T>> {
|
|
using PeekType = T*;
|
|
using ConstPeekType = const T*;
|
|
static unsigned hash(NonnullRefPtr<T> const& p) { return ptr_hash(p.ptr()); }
|
|
static bool equals(NonnullRefPtr<T> const& a, NonnullRefPtr<T> const& b) { return a.ptr() == b.ptr(); }
|
|
};
|
|
|
|
using AK::adopt_ref;
|
|
using AK::NonnullRefPtr;
|