cptr.hpp

Go to the documentation of this file.

// DUNE DAQ modification notice:
// This file has been modified from the original ATLAS dbe source for the DUNE DAQ project.
// Fork baseline commit: dbe-02-12-17 (2022-05-12).
// Renamed since fork: yes (from dbe/cptr.hpp to include/dbe/cptr.hpp).
 
/************************************************************
 * cptr.hpp                                             *
 *                                                          *
 *  Created on: Sep 14, 2014                                     *
 *      Author: Leonidas Georgopoulos                                     *
 *
 *  Copyright (C) 2014 Leonidas Georgopoulos
 *  Distributed under the Boost Software License, Version 1.0.
 *  (See accompanying file LICENSE_1_0.txt or
 *  copy at http://www.boost.org/LICENSE_1_0.txt)
 *
 ************************************************************/
#ifndef LUTILS_CPTR_HPP
#define LUTILS_CPTR_HPP
 
#include <chrono>
#include <iostream>
#include <memory>
#include <mutex>
#include <thread>
#include <utility>
 
template<typename T, typename M>
class cptr_proxy;
 
//-----------------------------------------------------------------------------------------------------
template<typename T, typename M = std::recursive_mutex, int N = 100>
class cptr
{
protected:
  std::shared_ptr<M> llock;
 
  T* base;
 
public:
  explicit cptr(T* p)
    : llock(new M())
    , base(p)
  {
  }
 
  cptr_proxy<T, M> operator->()
  {
    while (!llock->try_lock()) {
      std::this_thread::sleep_for(std::chrono::nanoseconds(N));
    }
 
    return *this;
  }
 
  cptr_proxy<T, M> operator->() const
  {
    while (!llock->try_lock()) {
      std::this_thread::sleep_for(std::chrono::nanoseconds(N));
    }
 
    return *this;
  }
 
  T* get() { return base; }
 
  T* get() const { return base; }
 
  friend class cptr_proxy<T, M>;
};
//-----------------------------------------------------------------------------------------------------
// template<typename T, typename M, int N> M cptr<T,M,N>::llock;
//-----------------------------------------------------------------------------------------------------
template<typename T, typename M>
class cptr_proxy
{
private:
  T* that;
 
  std::shared_ptr<M> llock_ptr;
 
public:
  cptr_proxy(cptr<T, M> const& cp)
    : that(cp.base)
    , llock_ptr(cp.llock)
  {
  }
 
  T* operator->() { return that; }
 
  ~cptr_proxy() { llock_ptr->unlock(); }
};
//-----------------------------------------------------------------------------------------------------
 
#endif /*LUTILS_CPTR_HPP*/