PeriodicTimer.h

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// $Id: PeriodicTimer.h,v 1.1 2010/02/23 17:19:58 eml Exp $

#ifndef GCP_UTIL_PERIODICTIMER_H
#define GCP_UTIL_PERIODICTIMER_H

#include <iostream>

#include "gcp/util/common/GenericTask.h"
#include "gcp/util/common/GenericTaskMsg.h"
#include "gcp/util/common/SpawnableTask.h"
#include "gcp/util/common/TimeOut.h"

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

namespace gcp {
  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;
    };

    //------------------------------------------------------------
    // A utility class used to store handlers
    //------------------------------------------------------------

    class Handler {
    public:
      PERIODIC_TIMER_HANDLER(*fn_);
      void* args_;
    };

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

    class PeriodicTimer : 
      public SpawnableTask<PeriodicTimerMsg> {
    public:

      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 gcp



#endif // End #ifndef GCP_UTIL_PERIODICTIMER_H