mirror of
https://github.com/zerotier/ZeroTierOne.git
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61 lines
1.3 KiB
C++
61 lines
1.3 KiB
C++
/*
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* Copyright (c)2013-2021 ZeroTier, Inc.
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file in the project's root directory.
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*
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* Change Date: 2026-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2.0 of the Apache License.
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*/
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/****/
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#ifndef ZT_SPINLOCK_HPP
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#define ZT_SPINLOCK_HPP
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#include "Constants.hpp"
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#include "Mutex.hpp"
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#ifdef __LINUX__
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#include <sched.h>
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#else
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#include <thread>
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#endif
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/**
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* Simple spinlock
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*
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* This can be used in place of Mutex to lock things that are extremely fast
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* to access. It should be used very sparingly.
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*/
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class Spinlock
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{
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public:
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ZT_INLINE Spinlock() noexcept: m_locked(false)
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{}
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ZT_INLINE void lock() noexcept
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{
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if (unlikely(m_locked.test_and_set(std::memory_order_acquire))) {
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do {
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#ifdef __LINUX__
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sched_yield();
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#else
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std::this_thread::yield();
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#endif
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} while (m_locked.test_and_set(std::memory_order_acquire));
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}
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}
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ZT_INLINE void unlock() noexcept
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{ m_locked.clear(std::memory_order_release); }
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private:
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ZT_INLINE Spinlock(const Spinlock &) noexcept {}
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ZT_INLINE const Spinlock &operator=(const Spinlock &) noexcept { return *this; }
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std::atomic_flag m_locked;
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};
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#endif
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