/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.

   GNU Mailutils is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Library Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   GNU Mailutils 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 Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with GNU Mailutils; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>

#include <mailutils/monitor.h>
#include <mailutils/error.h>
#include <mailutils/sys/refcount.h>

int
mu_refcount_create (mu_refcount_t *prefcount)
{
  mu_refcount_t refcount;
  if (prefcount == NULL)
    return MU_ERROR_INVALID_PARAMETER;
  refcount = calloc (1, sizeof *refcount);
  if (refcount == NULL)
    return MU_ERROR_NO_MEMORY;
  refcount->ref = 1;
  monitor_create (&(refcount->lock));
  *prefcount = refcount;
  return 0;
}

void
mu_refcount_destroy (mu_refcount_t *prefcount)
{
  if (prefcount && *prefcount)
    {
      mu_refcount_t refcount = *prefcount;
      monitor_destroy (&refcount->lock);
      free (refcount);
      *prefcount = NULL;
    }
}

int
mu_refcount_lock (mu_refcount_t refcount)
{
  if (refcount)
    return monitor_lock (refcount->lock);
  return 0;
}

int
mu_refcount_unlock (mu_refcount_t refcount)
{
  if (refcount)
    return monitor_unlock (refcount->lock);
  return 0;
}

int
mu_refcount_inc (mu_refcount_t refcount)
{
  int count = 0;
  if (refcount)
    {
      monitor_lock (refcount->lock);
      count = ++refcount->ref;
      monitor_unlock (refcount->lock);
    }
  return count;
}

int
mu_refcount_dec (mu_refcount_t refcount)
{
  int count = 0;
  if (refcount)
    {
      monitor_lock (refcount->lock);
      if (refcount->ref)
	count = --refcount->ref;
      monitor_unlock (refcount->lock);
    }
  return count;
}