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https://github.com/SerenityOS/serenity
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7014d37dd6
cert-dcl50-cpp: No variadic functions, suppressed in RefCounted and ThreadSafeRefCounted for implementing the magic one_ref_left and will_be_destroyed functions. cert-dcl58-cpp: No opening ::std, suppressed in the places we put names in ::std to aid tools (move, forward, nullptr_t, align_val_t, etc).
108 lines
2.5 KiB
C++
108 lines
2.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#ifdef KERNEL
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# include <Kernel/Library/ThreadSafeRefCounted.h>
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#else
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# include <AK/Assertions.h>
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# include <AK/Checked.h>
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# include <AK/Noncopyable.h>
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# include <AK/Platform.h>
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# include <AK/StdLibExtras.h>
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namespace AK {
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template<class T>
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constexpr auto call_will_be_destroyed_if_present(const T* object) -> decltype(const_cast<T*>(object)->will_be_destroyed(), TrueType {})
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{
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const_cast<T*>(object)->will_be_destroyed();
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return {};
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}
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// NOLINTNEXTLINE(cert-dcl50-cpp) variadic argument used to implement "is detected" pattern
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constexpr auto call_will_be_destroyed_if_present(...) -> FalseType
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{
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return {};
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}
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template<class T>
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constexpr auto call_one_ref_left_if_present(const T* object) -> decltype(const_cast<T*>(object)->one_ref_left(), TrueType {})
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{
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const_cast<T*>(object)->one_ref_left();
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return {};
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}
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// NOLINTNEXTLINE(cert-dcl50-cpp) variadic argument used to implement "is detected" pattern
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constexpr auto call_one_ref_left_if_present(...) -> FalseType
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{
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return {};
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}
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class RefCountedBase {
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AK_MAKE_NONCOPYABLE(RefCountedBase);
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AK_MAKE_NONMOVABLE(RefCountedBase);
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public:
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using RefCountType = unsigned int;
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using AllowOwnPtr = FalseType;
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ALWAYS_INLINE void ref() const
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{
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VERIFY(m_ref_count > 0);
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VERIFY(!Checked<RefCountType>::addition_would_overflow(m_ref_count, 1));
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++m_ref_count;
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}
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[[nodiscard]] bool try_ref() const
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{
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if (m_ref_count == 0)
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return false;
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ref();
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return true;
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}
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[[nodiscard]] RefCountType ref_count() const { return m_ref_count; }
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protected:
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RefCountedBase() = default;
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~RefCountedBase() { VERIFY(!m_ref_count); }
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ALWAYS_INLINE RefCountType deref_base() const
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{
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VERIFY(m_ref_count);
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return --m_ref_count;
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}
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RefCountType mutable m_ref_count { 1 };
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};
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template<typename T>
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class RefCounted : public RefCountedBase {
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public:
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bool unref() const
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{
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auto new_ref_count = deref_base();
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if (new_ref_count == 0) {
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call_will_be_destroyed_if_present(static_cast<const T*>(this));
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delete static_cast<const T*>(this);
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return true;
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} else if (new_ref_count == 1) {
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call_one_ref_left_if_present(static_cast<const T*>(this));
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}
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return false;
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}
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};
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}
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using AK::RefCounted;
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using AK::RefCountedBase;
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#endif
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