server_heartbeats.hpp

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#ifndef ISIMUD_EXCHANGES_COMMON_SERVER_HEARTBEATS_HPP
#define ISIMUD_EXCHANGES_COMMON_SERVER_HEARTBEATS_HPP
 
/******************************************************************************
** Copyright © 2018 by J.M.McGuiness, isimud@hussar.me.uk
**
** This library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public
** License as published by the Free Software Foundation; either
** version 2.1 of the License, or (at your option) any later version.
**
** This library is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
** Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser General Public
** License along with this library; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
 
#include "thread_traits.hpp"
 
#include "core/jthread.hpp"
 
#include <boost/exception_ptr.hpp>
 
#include <atomic>
#include <chrono>
#include <functional>
 
namespace isimud { namespace ISIMUD_VER_NAMESPACE { namespace exchanges { namespace common {
 
/// Section 5.2.2 "Heartbeats" of [1]. Generate heartbeats from the containing simulator.
/**
   The simulator generates heartbeats to which the client responds.
*/
template<class MsgT, unsigned MissedHbs, unsigned HbInterval>
class server_hb_t {
public:
   /// The specific heartbeat message type.
   using hb_t=MsgT;
 
   enum : unsigned {
      max_missed_heartbeats=MissedHbs
   };
   static inline constexpr std::chrono::seconds heartbeat_interval{HbInterval};
 
   template<class ClientCxn, class MakeHB>
   server_hb_t(ClientCxn &cxn, MakeHB &&make_hb);
   ~server_hb_t() noexcept(true);
 
   void stop() noexcept(true);
 
   std::string to_string() const noexcept(false);
 
   friend std::ostream &operator<<(std::ostream &os, server_hb_t const &s) noexcept(false) {
      os<<s.to_string();
      return os;
   }
 
   template<class ClientCxn>
   void process(ClientCxn &cxn) noexcept;
 
private:
   using thread_t=libjmmcg::ppd::jthread;
 
   std::atomic<bool> exit_;
   /**
      \todo Need to report errors correctly....
    */
   boost::exception_ptr hb_proc_ex;
   const std::function<hb_t()> make_hb_msg;
   thread_t heartbeat_sender_thr;
};
 
} } } }
 
#include "server_heartbeats_impl.hpp"
 
#endif