virtualx-engine/core/os/spin_lock.h

/**************************************************************************/
/*  spin_lock.h                                                           */
/**************************************************************************/
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/*                             GODOT ENGINE                               */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#ifndef SPIN_LOCK_H
#define SPIN_LOCK_H

#include "core/typedefs.h"

#if defined(__APPLE__)

#include <os/lock.h>

class SpinLock {
	mutable os_unfair_lock _lock = OS_UNFAIR_LOCK_INIT;

public:
	_ALWAYS_INLINE_ void lock() const {
		os_unfair_lock_lock(&_lock);
	}

	_ALWAYS_INLINE_ void unlock() const {
		os_unfair_lock_unlock(&_lock);
	}
};

#else

#include <atomic>

class SpinLock {
	mutable std::atomic_flag locked = ATOMIC_FLAG_INIT;

public:
	_ALWAYS_INLINE_ void lock() const {
		while (locked.test_and_set(std::memory_order_acquire)) {
			// Continue.
		}
	}
	_ALWAYS_INLINE_ void unlock() const {
		locked.clear(std::memory_order_release);
	}
};

#endif // __APPLE__

#endif // SPIN_LOCK_H