shutdown_alerter.h

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#ifndef SHUTDOWN_ALERTER_CLASS
#define SHUTDOWN_ALERTER_CLASS

/*****************************************************************************\
*                                                                             *
*  Name   : shutdown_alerter                                                  *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 2003-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/

#include "dll_processes.h"

#include <basis/object_base.h>
#include <opsystem/timer_driver.h>

// forward.
class istring_object;


class PROCESSES_CLASS_STYLE shutdown_alerter
: public virtual object_base, public timed_object
{
public:
  shutdown_alerter();

  virtual ~shutdown_alerter();

  IMPLEMENT_CLASS_NAME("shutdown_alerter");

  bool setup(const istring &app_name, int timer_period = 0);

  static bool is_defunct() { return _defunct(); }

  static void set_defunct();

  inline bool saw_interrupt() { return _saw_interrupt(); }

  // these virtual methods can be overridden by applications derived from the
  // shutdown_alerter.  they support a graceful shutdown process by which
  // applications can be alerted that they must shutdown, allowing them to take
  // care of releasing resources beforehand.

  virtual void handle_startup();

  virtual void handle_shutdown();

  virtual void handle_timer();

  // static methods that can be used by the program for starting up or for
  // graceful shutdown.

  static bool launch_console(shutdown_alerter &alert, const istring &app_name,
          int timer_period = 0);

#if 0  //not implemented.
#ifdef __WIN32__
  static bool launch_event_loop(shutdown_alerter &alert,
          const istring &app_name, int timer_period = 0);

#endif
#endif

  static void close_this_program();

  static bool close_application(const istring &app_name);

  // internal methods not to be used by outside objects.

  static void handle_OS_signal(int sig_id);

private:
  static bool &_saw_interrupt();  
  static istring_object &_app_name();  
  static bool &_defunct();  
  static int &_timer_period();  

  virtual void handle_timer_callback();

  // not appropriate.
  shutdown_alerter(const shutdown_alerter &);
  shutdown_alerter &operator =(const shutdown_alerter &);
};

#endif // outer guard.

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