dbus-list.c

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-list.c Generic linked list utility (internal to D-Bus implementation)
 *
 * Copyright (C) 2002  Red Hat, Inc.
 *
 * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
 *
 * Licensed under the Academic Free License version 2.1
 *
 * 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
 *
 */
 
#include <config.h>
#include "dbus-internals.h"
#include "dbus-list.h"
#include "dbus-mempool.h"
#include "dbus-threads-internal.h"
#include <dbus/dbus-test-tap.h>
 
/* Protected by _DBUS_LOCK (list) */
static DBusMemPool *list_pool;
 
/* the mem pool is probably a speed hit, with the thread
 * lock, though it does still save memory - unknown.
 */
static DBusList*
alloc_link (void *data)
{
  DBusList *link;
 
  if (!_DBUS_LOCK (list))
    return FALSE;
 
  if (list_pool == NULL)
    {      
      list_pool = _dbus_mem_pool_new (sizeof (DBusList), TRUE);
 
      if (list_pool == NULL)
        {
          _DBUS_UNLOCK (list);
          return NULL;
        }
 
      link = _dbus_mem_pool_alloc (list_pool);
      if (link == NULL)
        {
          _dbus_mem_pool_free (list_pool);
          list_pool = NULL;
          _DBUS_UNLOCK (list);
          return NULL;
        }
    }
  else
    {
      link = _dbus_mem_pool_alloc (list_pool);
    }
 
  if (link)
    link->data = data;
  
  _DBUS_UNLOCK (list);
 
  return link;
}
 
static void
free_link (DBusList *link)
{  
  if (!_DBUS_LOCK (list))
    _dbus_assert_not_reached ("we should have initialized global locks "
        "before we allocated a linked-list link");
 
  if (_dbus_mem_pool_dealloc (list_pool, link))
    {
      _dbus_mem_pool_free (list_pool);
      list_pool = NULL;
    }
  
  _DBUS_UNLOCK (list);
}
 
static void
link_before (DBusList **list,
             DBusList  *before_this_link,
             DBusList  *link)
{
  if (*list == NULL)
    {
      link->prev = link;
      link->next = link;
      *list = link;
    }
  else
    {      
      link->next = before_this_link;
      link->prev = before_this_link->prev;
      before_this_link->prev = link;
      link->prev->next = link;
      
      if (before_this_link == *list)
        *list = link;
    }
}
 
static void
link_after (DBusList **list,
            DBusList  *after_this_link,
            DBusList  *link)
{
  if (*list == NULL)
    {
      link->prev = link;
      link->next = link;
      *list = link;
    }
  else
    {
      link->prev = after_this_link;
      link->next = after_this_link->next;
      after_this_link->next = link;
      link->next->prev = link;
    }
}
 
#ifdef DBUS_ENABLE_STATS
void
_dbus_list_get_stats     (dbus_uint32_t *in_use_p,
                          dbus_uint32_t *in_free_list_p,
                          dbus_uint32_t *allocated_p)
{
  if (!_DBUS_LOCK (list))
    {
      *in_use_p = 0;
      *in_free_list_p = 0;
      *allocated_p = 0;
      return;
    }
 
  _dbus_mem_pool_get_stats (list_pool, in_use_p, in_free_list_p, allocated_p);
  _DBUS_UNLOCK (list);
}
#endif
 
DBusList*
_dbus_list_alloc_link (void *data)
{
  return alloc_link (data);
}
 
void
_dbus_list_free_link (DBusList *link)
{
  free_link (link);
}
 
 
dbus_bool_t
_dbus_list_append (DBusList **list,
                   void      *data)
{
  if (!_dbus_list_prepend (list, data))
    return FALSE;
 
  /* Now cycle the list forward one so the prepended node is the tail */
  *list = (*list)->next;
 
  return TRUE;
}
 
dbus_bool_t
_dbus_list_prepend (DBusList **list,
                    void      *data)
{
  DBusList *link;
 
  link = alloc_link (data);
  if (link == NULL)
    return FALSE;
 
  link_before (list, *list, link);
 
  return TRUE;
}
 
void
_dbus_list_append_link (DBusList **list,
                        DBusList *link)
{
  _dbus_list_prepend_link (list, link);
 
  /* Now cycle the list forward one so the prepended node is the tail */
  *list = (*list)->next;
}
 
void
_dbus_list_prepend_link (DBusList **list,
                         DBusList *link)
{
  link_before (list, *list, link);
}
 
dbus_bool_t
_dbus_list_insert_after (DBusList **list,
                         DBusList  *after_this_link,
                         void      *data)
{
  DBusList *link;  
 
  if (after_this_link == NULL)
    return _dbus_list_prepend (list, data);
  else
    {
      link = alloc_link (data);
      if (link == NULL)
        return FALSE;
  
      link_after (list, after_this_link, link);
    }
  
  return TRUE;
}
 
void
_dbus_list_insert_before_link (DBusList **list,
                               DBusList  *before_this_link,
                               DBusList  *link)
{
  if (before_this_link == NULL)
    _dbus_list_append_link (list, link);
  else
    link_before (list, before_this_link, link);
}
 
void
_dbus_list_insert_after_link (DBusList **list,
                              DBusList  *after_this_link,
                              DBusList  *link)
{
  if (after_this_link == NULL)
    _dbus_list_prepend_link (list, link);
  else  
    link_after (list, after_this_link, link);
}
 
dbus_bool_t
_dbus_list_remove (DBusList **list,
                   void      *data)
{
  DBusList *link;
 
  link = *list;
  while (link != NULL)
    {
      if (link->data == data)
        {
          _dbus_list_remove_link (list, link);
          return TRUE;
        }
      
      link = _dbus_list_get_next_link (list, link);
    }
 
  return FALSE;
}
 
dbus_bool_t
_dbus_list_remove_last (DBusList **list,
                        void      *data)
{
  DBusList *link;
 
  link = _dbus_list_find_last (list, data);
  if (link)
    {
      _dbus_list_remove_link (list, link);
      return TRUE;
    }
  else
    return FALSE;
}
 
DBusList*
_dbus_list_find_last (DBusList **list,
                      void      *data)
{
  DBusList *link;
 
  link = _dbus_list_get_last_link (list);
 
  while (link != NULL)
    {
      if (link->data == data)
        return link;
      
      link = _dbus_list_get_prev_link (list, link);
    }
 
  return NULL;
}
 
void
_dbus_list_unlink (DBusList **list,
                   DBusList  *link)
{
  if (link->next == link)
    {
      /* one-element list */
      *list = NULL;
    }
  else
    {      
      link->prev->next = link->next;
      link->next->prev = link->prev;
      
      if (*list == link)
        *list = link->next;
    }
 
  link->next = NULL;
  link->prev = NULL;
}
 
void
_dbus_list_remove_link (DBusList **list,
                        DBusList  *link)
{
  _dbus_list_unlink (list, link);
  free_link (link);
}
 
void
_dbus_list_clear (DBusList **list)
{
  DBusList *link;
 
  link = *list;
  while (link != NULL)
    {
      DBusList *next = _dbus_list_get_next_link (list, link);
      
      free_link (link);
      
      link = next;
    }
 
  *list = NULL;
}
 
void
_dbus_list_clear_full (DBusList         **list,
                       DBusFreeFunction   function)
{
  DBusList *link;
 
  link = *list;
  while (link != NULL)
    {
      DBusList *next = _dbus_list_get_next_link (list, link);
 
      function (link->data);
      free_link (link);
 
      link = next;
    }
 
  *list = NULL;
}
 
DBusList*
_dbus_list_get_first_link (DBusList **list)
{
  return *list;
}
 
DBusList*
_dbus_list_get_last_link (DBusList **list)
{
  if (*list == NULL)
    return NULL;
  else
    return (*list)->prev;
}
 
void*
_dbus_list_get_last (DBusList **list)
{
  if (*list == NULL)
    return NULL;
  else
    return (*list)->prev->data;
}
 
void*
_dbus_list_get_first (DBusList **list)
{
  if (*list == NULL)
    return NULL;
  else
    return (*list)->data;
}
 
DBusList*
_dbus_list_pop_first_link (DBusList **list)
{
  DBusList *link;
  
  link = _dbus_list_get_first_link (list);
  if (link == NULL)
    return NULL;
 
  _dbus_list_unlink (list, link);
 
  return link;
}
 
void*
_dbus_list_pop_first (DBusList **list)
{
  DBusList *link;
  void *data;
  
  link = _dbus_list_get_first_link (list);
  if (link == NULL)
    return NULL;
  
  data = link->data;
  _dbus_list_remove_link (list, link);
 
  return data;
}
 
void*
_dbus_list_pop_last (DBusList **list)
{
  DBusList *link;
  void *data;
  
  link = _dbus_list_get_last_link (list);
  if (link == NULL)
    return NULL;
  
  data = link->data;
  _dbus_list_remove_link (list, link);
 
  return data;
}
 
dbus_bool_t
_dbus_list_copy (DBusList **list,
                 DBusList **dest)
{
  DBusList *link;
 
  _dbus_assert (list != dest);
 
  *dest = NULL;
  
  link = *list;
  while (link != NULL)
    {
      if (!_dbus_list_append (dest, link->data))
        {
          /* free what we have so far */
          _dbus_list_clear (dest);
          return FALSE;
        }
      
      link = _dbus_list_get_next_link (list, link);
    }
 
  return TRUE;
}
 
int
_dbus_list_get_length (DBusList **list)
{
  DBusList *link;
  int length;
 
  length = 0;
  
  link = *list;
  while (link != NULL)
    {
      ++length;
      
      link = _dbus_list_get_next_link (list, link);
    }
 
  return length;
}
 
void
_dbus_list_foreach (DBusList          **list,
                    DBusForeachFunction function,
                    void               *data)
{
  DBusList *link;
 
  link = *list;
  while (link != NULL)
    {
      DBusList *next = _dbus_list_get_next_link (list, link);
      
      (* function) (link->data, data);
      
      link = next;
    }
}
 
dbus_bool_t
_dbus_list_length_is_one (DBusList **list)
{
  return (*list != NULL &&
          (*list)->next == *list);
}