////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave 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 3 of the License, or
// (at your option) any later version.
//
// Octave 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if ! defined (octave_singleton_cleanup_h)
#define octave_singleton_cleanup_h 1

#include "octave-config.h"

#include <set>

class
OCTAVE_API
singleton_cleanup_list
{
protected:

  singleton_cleanup_list (void) : m_fcn_list () { }

public:

  typedef void (*fptr) (void);

  // No copying!

  singleton_cleanup_list (const singleton_cleanup_list&) = delete;

  singleton_cleanup_list& operator = (const singleton_cleanup_list&) = delete;

  ~singleton_cleanup_list (void);

  static void add (fptr f)
  {
    if (instance_ok ())
      s_instance->do_add (f);
  }

  static void cleanup (void)
  {
    delete s_instance;
    s_instance = nullptr;
  }

private:

  static singleton_cleanup_list *s_instance;

  static bool instance_ok (void);

  static void cleanup_instance (void)
  {
    delete s_instance;
    s_instance = nullptr;
  }

  std::set<fptr> m_fcn_list;

  void do_add (fptr f)
  {
    m_fcn_list.insert (f);
  }
};

#endif