TRWSpinLock.hxx

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// @(#)root/thread:$Id$
// Authors: Enric Tejedor CERN  12/09/2016
//          Philippe Canal FNAL 12/09/2016

/*************************************************************************
 * Copyright (C) 1995-2016, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#ifndef ROOT_TRWSpinLock
#define ROOT_TRWSpinLock

#include "TSpinMutex.hxx"

#include <atomic>
#include <condition_variable>


namespace ROOT {
   class TRWSpinLock {
   private:
      std::atomic<int>             fReaders; ///<! Number of readers
      std::atomic<int>             fReaderReservation; ///<! A reader wants access
      std::atomic<int>             fWriterReservation; ///<! A writer wants access
      std::atomic<bool>            fWriter;  ///<! Is there a writer?
      ROOT::TSpinMutex             fMutex;   ///<! RWlock internal mutex
      std::condition_variable_any  fCond;    ///<! RWlock internal condition variable

   public:
      ////////////////////////////////////////////////////////////////////////
      /// Regular constructor.
      TRWSpinLock() : fReaders(0), fReaderReservation(0), fWriterReservation(0), fWriter(false) {}

      void ReadLock();
      void ReadUnLock();
      void WriteLock();
      void WriteUnLock();
   };
} // end of namespace ROOT

#endif