/* Copyright (C) 1979-1996 TcX AB & Monty Program KB & Detron HB

   This software is distributed with NO WARRANTY OF ANY KIND.  No author or
   distributor accepts any responsibility for the consequences of using it, or
   for whether it serves any particular purpose or works at all, unless he or
   she says so in writing.  Refer to the Free Public License (the "License")
   for full details.

   Every copy of this file must include a copy of the License, normally in a
   plain ASCII text file named PUBLIC.	The License grants you the right to
   copy, modify and redistribute this file, but only under certain conditions
   described in the License.  Among other things, the License requires that
   the copyright notice and this notice be preserved on all copies. */

#ifdef __GNUC__
#pragma implementation				// gcc: Class implementation
#endif

#include "mysql_priv.h"
#ifdef HAVE_MMAP
#include <sys/mman.h>
#include <sys/stat.h>
#endif

#ifndef MAP_NORESERVE
#define MAP_NORESERVE 0				// For IRIX
#endif

mapped_files::mapped_files(const my_string filename,byte *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=(byte*) mmap(0,(size=(ulong) stat_buf.st_size),PROT_READ,
			     MAP_SHARED | MAP_NORESERVE,file,
			     0L)))
      {
	error=errno;
	my_printf_error(0,"Can't map file: %s, errno: %d",MYF(0),
			(my_string) name,error);
      }
    }
    if (map && memcmp(map,magic,magic_length))
    {
      my_printf_error(0,"Wrong magic in %s",MYF(0),name);
      VOID(munmap(map,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(munmap((caddr_t) map,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 my_string name,byte *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_printf_error(0,"Can't map file: %s, error: %d",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 __GNUC__
/* Used templates */
template class I_List<mapped_files>;
template class I_List_iterator<mapped_files>;
#endif