/home/mhx/git/github/libmoost/include/moost/process/quit_handler.hpp

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/* vim:set ts=3 sw=3 sts=3 et: */
#ifndef MOOST_UTILS_QUIT_HANDLER_HPP__
#define MOOST_UTILS_QUIT_HANDLER_HPP__

#include <csignal>
#include <cstdlib>

#include <boost/function.hpp>

#include "hup_handler.hpp"

namespace moost { namespace process {

   //

   class quit_handler
   {
   private:
      // A Meyers Singleton (http://bit.ly/EsS4p)
      static quit_handler & get_single_instance()
      {
         static quit_handler quit_handler;
         return quit_handler;
      }

   public:
      typedef boost::function<void ()> handler_t;

      // Set the customer handler.
      static void set(handler_t const & handler, bool trap_abort = true, bool trap_hup = false)
      {
         quit_handler & quit_handler = quit_handler::get_single_instance();
         quit_handler.handler_ = handler;
         quit_handler.register_handler(trap_abort);

         if(trap_hup)
         {
            // Register with hup_handler, as this knows all about SIGHUP
            hup_handler::set(handler);
         }
      }

   private:
      handler_t handler_;

      // This is the proxy handler, which calls the custom handler
      static void sighandler(int)
      {
         quit_handler & quit_handler = quit_handler::get_single_instance();

         if(quit_handler.handler_)
         {
            quit_handler.handler_();
         }
      }

      // Register the proxy handler
      struct sigaction sa_;
      void register_handler(bool trap_abort)
      {
         memset(&sa_, 0, sizeof(sa_));
         sa_.sa_handler = quit_handler::sighandler;

         sigemptyset(&sa_.sa_mask);
         sa_.sa_flags = SIG_BLOCK;

         // These are the signals we'll block whilst the handlers being called
         sigaddset(&sa_.sa_mask, SIGINT);
         sigaddset(&sa_.sa_mask, SIGTERM);
         sigaddset(&sa_.sa_mask, SIGQUIT);

         if (trap_abort) { sigaddset(&sa_.sa_mask, SIGABRT); }

         // These are the signals we'll trap and handle
         sigaction(SIGINT, &sa_, NULL);
         sigaction(SIGTERM, &sa_, NULL);
         sigaction(SIGQUIT, &sa_, NULL);

         if (trap_abort) { sigaction(SIGABRT, &sa_, NULL); }
      }
   };

}}

#endif // MOOST_UTILS_QUIT_HANDLER_HPP__