Boost C++ Libraries

boost/interprocess/sync/detail/condition_any_algorithm.hpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2012-2012. 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)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_INTERPROCESS_DETAIL_CONDITION_ANY_ALGORITHM_HPP
#define BOOST_INTERPROCESS_DETAIL_CONDITION_ANY_ALGORITHM_HPP

#ifndef BOOST_CONFIG_HPP
#  include <boost/config.hpp>
#endif
#
#if defined(BOOST_HAS_PRAGMA_ONCE)
#  pragma once
#endif

#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <boost/interprocess/sync/detail/locks.hpp>
#include <limits>

namespace boost {
namespace interprocess {
namespace ipcdetail {

////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
//
// Condition variable 'any' (able to use any type of external mutex)
//
// The code is based on Howard E. Hinnant's ISO C++ N2406 paper.
// Many thanks to Howard for his support and comments.
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////

// Required interface for ConditionAnyMembers
// class ConditionAnyMembers
// {
//    typedef implementation_defined mutex_type;
//    typedef implementation_defined condvar_type;
//
//    condvar     &get_condvar()
//    mutex_type  &get_mutex()
// };
//
// Must be initialized as following
//
//    get_condvar()  [no threads blocked]
//    get_mutex()    [unlocked]

template<class ConditionAnyMembers>
class condition_any_algorithm
{
   private:
   condition_any_algorithm();
   ~condition_any_algorithm();
   condition_any_algorithm(const condition_any_algorithm &);
   condition_any_algorithm &operator=(const condition_any_algorithm &);

   typedef typename ConditionAnyMembers::mutex_type      mutex_type;
   typedef typename ConditionAnyMembers::condvar_type    condvar_type;

   public:
   template <class Lock>
   static void wait(ConditionAnyMembers& data, Lock& lock)
   {
      //lock internal before unlocking external to avoid race with a notifier
      scoped_lock<mutex_type> internal_lock(data.get_mutex());
      {
         lock_inverter<Lock> inverted_lock(lock);
         scoped_lock<lock_inverter<Lock> >   external_unlock(inverted_lock);
         {  //unlock internal first to avoid deadlock with near simultaneous waits
            scoped_lock<mutex_type>     internal_unlock;
            internal_lock.swap(internal_unlock);
            data.get_condvar().wait(internal_unlock);
         }
      }
   }

   template <class Lock, class TimePoint>
   static bool timed_wait(ConditionAnyMembers &data, Lock& lock, const TimePoint &abs_time)
   {
      //lock internal before unlocking external to avoid race with a notifier
      scoped_lock<mutex_type> internal_lock(data.get_mutex());
      {
         //Unlock external lock and program for relock
         lock_inverter<Lock> inverted_lock(lock);
         scoped_lock<lock_inverter<Lock> >   external_unlock(inverted_lock);
         {  //unlock internal first to avoid deadlock with near simultaneous waits
            scoped_lock<mutex_type> internal_unlock;
            internal_lock.swap(internal_unlock);
            return data.get_condvar().timed_wait(internal_unlock, abs_time);
         }
      }
   }

   static void signal(ConditionAnyMembers& data, bool broadcast)
   {
      scoped_lock<mutex_type> internal_lock(data.get_mutex());
      if(broadcast){
         data.get_condvar().notify_all();
      }
      else{
         data.get_condvar().notify_one();
      }
   }
};


template<class ConditionAnyMembers>
class condition_any_wrapper
{
   //Non-copyable
   condition_any_wrapper(const condition_any_wrapper &);
   condition_any_wrapper &operator=(const condition_any_wrapper &);

   ConditionAnyMembers m_data;
   typedef ipcdetail::condition_any_algorithm<ConditionAnyMembers> algo_type;

   public:

   condition_any_wrapper(){}

   ~condition_any_wrapper(){}

   ConditionAnyMembers & get_members()
   {  return m_data; }

   const ConditionAnyMembers & get_members() const
   {  return m_data; }

   void notify_one()
   {  algo_type::signal(m_data, false);  }

   void notify_all()
   {  algo_type::signal(m_data, true);  }

   template <typename Lock>
   void wait(Lock& lock)
   {
      if (!lock)
         throw lock_exception();
      algo_type::wait(m_data, lock);
   }

   template <typename L, typename Pr>
   void wait(L& lock, Pr pred)
   {
      if (!lock)
         throw lock_exception();

      while (!pred())
         algo_type::wait(m_data, lock);
   }

   template <typename L, typename TimePoint>
   bool timed_wait(L& lock, const TimePoint &abs_time)
   {
      if (!lock)
         throw lock_exception();
      return algo_type::timed_wait(m_data, lock, abs_time);
   }

   template <typename L, typename TimePoint, typename Pr>
   bool timed_wait(L& lock, const TimePoint &abs_time, Pr pred)
   {
      if (!lock)
            throw lock_exception();
      while (!pred()){
         if (!algo_type::timed_wait(m_data, lock, abs_time))
            return pred();
      }
      return true;
   }
};

}  //namespace ipcdetail
}  //namespace interprocess
}  //namespace boost

#include <boost/interprocess/detail/config_end.hpp>

#endif   //BOOST_INTERPROCESS_DETAIL_CONDITION_ANY_ALGORITHM_HPP