PeriodicTimer.h

// $Id: PeriodicTimer.h,v 1.2 2011/11/14 22:42:03 eml Exp $

#ifndef SZA_UTIL_PERIODICTIMER_H
#define SZA_UTIL_PERIODICTIMER_H

#include <iostream>

#include "carma/szautil/GenericTask.h"
#include "carma/szautil/GenericTaskMsg.h"
#include "carma/szautil/SpawnableTask.h"
#include "carma/szautil/TimeOut.h"

#define PERIODIC_TIMER_HANDLER(fn) void (fn)(void* args)

namespace sza {
  namespace util {

    //------------------------------------------------------------
    // A utility class for sending messages to the ModemPager task
    //------------------------------------------------------------

    class PeriodicTimerMsg : public GenericTaskMsg {
    public:

      enum MsgType {
        TIMER,
        ADD_HANDLER,
        REM_HANDLER
      };
      
      union {

        struct {
          bool enable;
          unsigned intervalInSeconds;
        } timer;

        struct {
          PERIODIC_TIMER_HANDLER(*fn);
          void* args;
        } addHandler;

        struct {
          PERIODIC_TIMER_HANDLER(*fn);
        } remHandler;

      } body;
      
      // A type for this message

      MsgType type;
    };

    //------------------------------------------------------------
    // Main class definition
    //------------------------------------------------------------

    class PeriodicTimer : 
      public SpawnableTask<PeriodicTimerMsg> {
    public:

        //------------------------------------------------------------
        // A utility class used to store handlers
        //------------------------------------------------------------
        
        class Handler {
        public:
          PERIODIC_TIMER_HANDLER(*fn_);
          void* args_;
        };

      PeriodicTimer();

      virtual ~PeriodicTimer();

      // Add a callback function to be called whenever the timer expires

      void addHandler(PERIODIC_TIMER_HANDLER(*handler), void* args=0);

      // Remove a callback function from the list to be called

      void removeHandler(PERIODIC_TIMER_HANDLER(*handler));

      // Enable/Disable the timer

      void enableTimer(bool enable, unsigned intervalInSeconds=0);

    private:

      TimeOut timeOut_;

      // A list of handlers to be called when the ephemeris is updated

      std::vector<Handler> handlers_; 

      //-----------------------------------------------------------------------
      // Methods called in response to messages received on our message queue
      //-----------------------------------------------------------------------

      void executeEnableTimer(bool enable, unsigned intervalInSeconds);
      void executeAddHandler(PERIODIC_TIMER_HANDLER(*handler), void* args=0);
      void executeRemoveHandler(PERIODIC_TIMER_HANDLER(*handler));

      //-----------------------------------------------------------------------
      // Run methods used by this class
      //-----------------------------------------------------------------------

      void serviceMsgQ();
      void processMsg(PeriodicTimerMsg* msg);

      // React to a timeout in select

      void registerTimeOut();

      void callHandlers();

    }; // End class PeriodicTimer

  } // End namespace util
} // End namespace sza



#endif // End #ifndef SZA_UTIL_PERIODICTIMER_H