spinmutex.cc

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#include "ion/base/spinmutex.h"

#include "ion/base/logging.h"
#include "ion/port/threadutils.h"

namespace ion {
namespace base {

SpinMutex::~SpinMutex() { DCHECK(!IsLocked()); }

void SpinMutex::Lock() {
  unsigned int try_count = 0;
  bool already_locked = false;
  while (!locked_.compare_exchange_weak(
             already_locked, true, std::memory_order_acquire)) {
    already_locked = false;
    if (++try_count > 1000) {
      port::YieldThread();
    }
  }
}

bool SpinMutex::TryLock() {
  bool already_locked = false;
  return locked_.compare_exchange_strong(
      already_locked, true, std::memory_order_acquire);
}

void SpinMutex::Unlock() {
  DCHECK(IsLocked());
  locked_.store(false, std::memory_order_release);
}

}  // namespace base
}  // namespace ion