mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-11-11 01:06:01 +03:00
1682f0b760
SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
111 lines
2.8 KiB
C++
111 lines
2.8 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/Checked.h>
|
|
#include <AK/Noncopyable.h>
|
|
#include <AK/Platform.h>
|
|
#include <AK/StdLibExtras.h>
|
|
|
|
namespace AK {
|
|
|
|
template<class T>
|
|
constexpr auto call_will_be_destroyed_if_present(const T* object) -> decltype(const_cast<T*>(object)->will_be_destroyed(), TrueType {})
|
|
{
|
|
const_cast<T*>(object)->will_be_destroyed();
|
|
return {};
|
|
}
|
|
|
|
constexpr auto call_will_be_destroyed_if_present(...) -> FalseType
|
|
{
|
|
return {};
|
|
}
|
|
|
|
template<class T>
|
|
constexpr auto call_one_ref_left_if_present(const T* object) -> decltype(const_cast<T*>(object)->one_ref_left(), TrueType {})
|
|
{
|
|
const_cast<T*>(object)->one_ref_left();
|
|
return {};
|
|
}
|
|
|
|
constexpr auto call_one_ref_left_if_present(...) -> FalseType
|
|
{
|
|
return {};
|
|
}
|
|
|
|
class RefCountedBase {
|
|
AK_MAKE_NONCOPYABLE(RefCountedBase);
|
|
AK_MAKE_NONMOVABLE(RefCountedBase);
|
|
|
|
public:
|
|
using RefCountType = unsigned int;
|
|
using AllowOwnPtr = FalseType;
|
|
|
|
ALWAYS_INLINE void ref() const
|
|
{
|
|
auto old_ref_count = m_ref_count.fetch_add(1, AK::MemoryOrder::memory_order_relaxed);
|
|
VERIFY(old_ref_count > 0);
|
|
VERIFY(!Checked<RefCountType>::addition_would_overflow(old_ref_count, 1));
|
|
}
|
|
|
|
[[nodiscard]] ALWAYS_INLINE bool try_ref() const
|
|
{
|
|
RefCountType expected = m_ref_count.load(AK::MemoryOrder::memory_order_relaxed);
|
|
for (;;) {
|
|
if (expected == 0)
|
|
return false;
|
|
VERIFY(!Checked<RefCountType>::addition_would_overflow(expected, 1));
|
|
if (m_ref_count.compare_exchange_strong(expected, expected + 1, AK::MemoryOrder::memory_order_acquire))
|
|
return true;
|
|
}
|
|
}
|
|
|
|
ALWAYS_INLINE RefCountType ref_count() const
|
|
{
|
|
return m_ref_count.load(AK::MemoryOrder::memory_order_relaxed);
|
|
}
|
|
|
|
protected:
|
|
RefCountedBase() = default;
|
|
ALWAYS_INLINE ~RefCountedBase()
|
|
{
|
|
VERIFY(m_ref_count.load(AK::MemoryOrder::memory_order_relaxed) == 0);
|
|
}
|
|
|
|
ALWAYS_INLINE RefCountType deref_base() const
|
|
{
|
|
auto old_ref_count = m_ref_count.fetch_sub(1, AK::MemoryOrder::memory_order_acq_rel);
|
|
VERIFY(old_ref_count > 0);
|
|
return old_ref_count - 1;
|
|
}
|
|
|
|
mutable Atomic<RefCountType> m_ref_count { 1 };
|
|
};
|
|
|
|
template<typename T>
|
|
class RefCounted : public RefCountedBase {
|
|
public:
|
|
bool unref() const
|
|
{
|
|
auto new_ref_count = deref_base();
|
|
if (new_ref_count == 0) {
|
|
call_will_be_destroyed_if_present(static_cast<const T*>(this));
|
|
delete static_cast<const T*>(this);
|
|
return true;
|
|
} else if (new_ref_count == 1) {
|
|
call_one_ref_left_if_present(static_cast<const T*>(this));
|
|
}
|
|
return false;
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
using AK::RefCounted;
|