~drizzle-trunk/drizzle/development

/* Copyright (C) 2000-2001, 2004-2005 MySQL AB

   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; version 2 of the License.

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifdef USE_PRAGMA_IMPLEMENTATION

#pragma implementation				// gcc: Class implementation

#endif

#include "mysql_priv.h"

#include <sys/stat.h>

#ifdef HAVE_SYS_MMAN_H

#include <sys/mman.h>

#endif

mapped_files::mapped_files(const char * filename,uchar *magic,uint magic_length)

{

#ifdef HAVE_MMAP

  name=my_strdup(filename,MYF(0));

  use_count=1;

  error=0;

  map=0;

  size=0;

  if ((file=my_open(name,O_RDONLY,MYF(MY_WME))) >= 0)

  {

    struct stat stat_buf;

    if (!fstat(file,&stat_buf))

    {

      if (!(map=(uchar*) my_mmap(0,(size_t)(size= stat_buf.st_size),PROT_READ,

			     MAP_SHARED | MAP_NORESERVE,file,

			     0L)))

      {

	error=errno;

	my_error(ER_NO_FILE_MAPPING, MYF(0), (char *) name, error);

      }

    }

    if (map && memcmp(map,magic,magic_length))

    {

      my_error(ER_WRONG_MAGIC, MYF(0), name);

      VOID(my_munmap((char*) map,(size_t)size));

      map=0;

    }

    if (!map)

    {

      VOID(my_close(file,MYF(0)));

      file= -1;

    }

  }

#endif

}

mapped_files::~mapped_files()

{

#ifdef HAVE_MMAP

  if (file >= 0)

  {

    VOID(my_munmap((char*) map,(size_t)size));

    VOID(my_close(file,MYF(0)));

    file= -1; map=0;

  }

  my_free(name,MYF(0));

#endif

}

static I_List<mapped_files> maps_in_use;

/*

**  Check if a file is mapped. If it is, then return pointer to old map,

**  else alloc new object

*/

mapped_files *map_file(const char * name,uchar *magic,uint magic_length)

{

#ifdef HAVE_MMAP

  VOID(pthread_mutex_lock(&LOCK_mapped_file));

  I_List_iterator<mapped_files> list(maps_in_use);

  mapped_files *map;

  char path[FN_REFLEN];

  sprintf(path,"%s/%s/%s.uniq",mysql_data_home,current_thd->db,name);

  (void) unpack_filename(path,path);

  while ((map=list++))

  {

    if (!strcmp(path,map->name))

      break;

  }

  if (!map)

  {

    map=new mapped_files(path,magic,magic_length);

    maps_in_use.append(map);

  }

  else

  {

    map->use_count++;

    if (!map->map)

      my_error(ER_NO_FILE_MAPPING, MYF(0), path, map->error);

  }

  VOID(pthread_mutex_unlock(&LOCK_mapped_file));

  return map;

#else

  return NULL;

#endif

}

/*

** free the map if there are no more users for it

*/

void unmap_file(mapped_files *map)

{

#ifdef HAVE_MMAP

  VOID(pthread_mutex_lock(&LOCK_mapped_file));

  if (!map->use_count--)

    delete map;

  VOID(pthread_mutex_unlock(&LOCK_mapped_file));

#endif

}

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

** Instansiate templates

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

#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION

/* Used templates */

template class I_List<mapped_files>;

template class I_List_iterator<mapped_files>;

#endif