spinlock.h

#pragma once
#include "gaia/config/config.h"
 
#include <atomic>
 
namespace gaia {
  namespace mt {
    class GAIA_API SpinLock final {
      std::atomic_int32_t m_value{};
 
    public:
      SpinLock() = default;
      SpinLock(const SpinLock&) = delete;
      SpinLock& operator=(const SpinLock&) = delete;
 
      bool try_lock() {
        // Attempt to acquire the lock without waiting
        return 0 == m_value.exchange(1, std::memory_order_acquire);
      }
 
      void lock() {
        while (true) {
          // The value has been changed, we successfully entered the lock
          if (0 == m_value.exchange(1, std::memory_order_acquire))
            break;
 
          // Yield until unlocked
          while (m_value.load(std::memory_order_relaxed) != 0)
            GAIA_YIELD_CPU;
        }
      }
 
      void unlock() {
        // Release the lock
        m_value.store(0, std::memory_order_release);
      }
    };
  } // namespace mt
} // namespace gaia