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https://github.com/SerenityOS/serenity
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c2a900b853
These instances were detected by searching for files that include AK/StdLibExtras.h, but don't match the regex: \\b(abs|AK_REPLACED_STD_NAMESPACE|array_size|ceil_div|clamp|exchange|for ward|is_constant_evaluated|is_power_of_two|max|min|mix|move|_RawPtr|RawP tr|round_up_to_power_of_two|swap|to_underlying)\\b (Without the linebreaks.) This regex is pessimistic, so there might be more files that don't actually use any "extra stdlib" functions. In theory, one might use LibCPP to detect things like this automatically, but let's do this one step after another.
89 lines
2.3 KiB
C++
89 lines
2.3 KiB
C++
/*
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* Copyright (c) 2018-2022, 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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#include <AK/Assertions.h>
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#include <AK/Atomic.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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namespace AK {
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class AtomicRefCountedBase {
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AK_MAKE_NONCOPYABLE(AtomicRefCountedBase);
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AK_MAKE_NONMOVABLE(AtomicRefCountedBase);
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public:
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using RefCountType = unsigned int;
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using AllowOwnPtr = FalseType;
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void ref() const
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{
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auto old_ref_count = m_ref_count.fetch_add(1, AK::MemoryOrder::memory_order_relaxed);
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VERIFY(old_ref_count > 0);
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VERIFY(!Checked<RefCountType>::addition_would_overflow(old_ref_count, 1));
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}
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[[nodiscard]] bool try_ref() const
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{
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RefCountType expected = m_ref_count.load(AK::MemoryOrder::memory_order_relaxed);
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for (;;) {
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if (expected == 0)
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return false;
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VERIFY(!Checked<RefCountType>::addition_would_overflow(expected, 1));
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if (m_ref_count.compare_exchange_strong(expected, expected + 1, AK::MemoryOrder::memory_order_acquire))
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return true;
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}
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}
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[[nodiscard]] RefCountType ref_count() const
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{
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return m_ref_count.load(AK::MemoryOrder::memory_order_relaxed);
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}
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protected:
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AtomicRefCountedBase() = default;
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~AtomicRefCountedBase()
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{
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VERIFY(m_ref_count.load(AK::MemoryOrder::memory_order_relaxed) == 0);
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}
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RefCountType deref_base() const
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{
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auto old_ref_count = m_ref_count.fetch_sub(1, AK::MemoryOrder::memory_order_acq_rel);
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VERIFY(old_ref_count > 0);
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return old_ref_count - 1;
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}
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mutable Atomic<RefCountType> m_ref_count { 1 };
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};
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template<typename T>
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class AtomicRefCounted : public AtomicRefCountedBase {
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public:
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bool unref() const
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{
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auto* that = const_cast<T*>(static_cast<T const*>(this));
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auto new_ref_count = deref_base();
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if (new_ref_count == 0) {
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if constexpr (requires { that->will_be_destroyed(); })
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that->will_be_destroyed();
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delete that;
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return true;
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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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#if USING_AK_GLOBALLY
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using AK::AtomicRefCounted;
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using AK::AtomicRefCountedBase;
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#endif
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