/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * 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 program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/uds-releases/jasper/src/uds/threadOnce.c#1 $

 */

#include "errors.h"

#include "threads.h"

enum {

  ONCE_NOT_DONE    = 0,

  ONCE_IN_PROGRESS = 1,

  ONCE_COMPLETE    = 2,

};

/*****************************************************************************/

int performOnce(OnceState *once, void (*function)(void))

{

  for (;;) {

    switch (atomic_cmpxchg(once, ONCE_NOT_DONE, ONCE_IN_PROGRESS)) {

    case ONCE_NOT_DONE:

      function();

      atomic_set_release(once, ONCE_COMPLETE);

      return UDS_SUCCESS;

    case ONCE_IN_PROGRESS:

      yieldScheduler();

      break;

    case ONCE_COMPLETE:

      return UDS_SUCCESS;

    default:

      return UDS_BAD_STATE;

    }

  }

}