instrumented_mutex.h

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/* Copyright (c) 2023, 2024, Oracle and/or its affiliates.
 
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   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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#ifndef INSTRUMENTED_MUTEX_H
#define INSTRUMENTED_MUTEX_H
#include <mutex>
#include "mysql/components/services/mysql_mutex.h"
 
namespace mysql {
/**
  mutex is a C++ STL mutex (std::mutex) implementation using the
  instrumented MySQL mutex component API.
 
  This allows for P_S instrumentation of mutexes in components.
 
  Example usage:
  @code
  #include <mysql/components/library_mysys/instrumented_mutex.h>
  namespace x {
    ...
    using mysql::mutex;
    ...
    mutex m(KEY_psi_mutex);
    ...
    std::unique_lock(m);
    ...
  };
  @endcode
*/
 
class mutex {
 public:
  mutex(PSI_mutex_key key) noexcept : m_key(key) {
    mysql_mutex_init(m_key, &m_mtx, 0);
  }
  mutex(const mutex &) = delete;
  ~mutex() { mysql_mutex_destroy(&m_mtx); }
  void lock() { mysql_mutex_lock(&m_mtx); }
  bool try_lock() { return 0 == mysql_mutex_trylock(&m_mtx); }
  void unlock() { mysql_mutex_unlock(&m_mtx); }
  mysql_mutex_t *native_handle() { return &m_mtx; }
 
 protected:
  mysql_mutex_t m_mtx;
  PSI_mutex_key m_key;
};
 
}  // namespace mysql
 
#endif  // INSTRUMENTED_MUTEX_H