MGMDB/MySQL/mf_cache.c
2011-10-02 20:48:43 -05:00

122 lines
3.4 KiB
C

/* Copyright (C) 2000 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 */
/* Open a temporary file and cache it with io_cache. Delete it on close */
#include "mysys_priv.h"
#include <m_string.h>
#include "my_static.h"
#include "mysys_err.h"
/*
Remove an open tempfile so that it doesn't survive
if we crash; If the operating system doesn't support
this, just remember the file name for later removal
*/
static my_bool cache_remove_open_tmp(IO_CACHE *cache __attribute__((unused)),
const char *name)
{
#if O_TEMPORARY == 0
#if !defined(CANT_DELETE_OPEN_FILES)
/* The following should always succeed */
(void) my_delete(name,MYF(MY_WME | ME_NOINPUT));
#else
int length;
if (!(cache->file_name=
(char*) my_malloc((length=strlen(name)+1),MYF(MY_WME))))
{
my_close(cache->file,MYF(0));
cache->file = -1;
errno=my_errno=ENOMEM;
return 1;
}
memcpy(cache->file_name,name,length);
#endif
#endif /* O_TEMPORARY == 0 */
return 0;
}
/*
** Open tempfile cached by IO_CACHE
** Should be used when no seeks are done (only reinit_io_buff)
** Return 0 if cache is inited ok
** The actual file is created when the IO_CACHE buffer gets filled
** If dir is not given, use TMPDIR.
*/
my_bool open_cached_file(IO_CACHE *cache, const char* dir, const char *prefix,
size_t cache_size, myf cache_myflags)
{
DBUG_ENTER("open_cached_file");
cache->dir= dir ? my_strdup(dir,MYF(cache_myflags & MY_WME)) : (char*) 0;
cache->prefix= (prefix ? my_strdup(prefix,MYF(cache_myflags & MY_WME)) :
(char*) 0);
cache->file_name=0;
cache->buffer=0; /* Mark that not open */
if (!init_io_cache(cache,-1,cache_size,WRITE_CACHE,0L,0,
MYF(cache_myflags | MY_NABP)))
{
DBUG_RETURN(0);
}
my_free(cache->dir, MYF(MY_ALLOW_ZERO_PTR));
my_free(cache->prefix,MYF(MY_ALLOW_ZERO_PTR));
DBUG_RETURN(1);
}
/* Create the temporary file */
my_bool real_open_cached_file(IO_CACHE *cache)
{
char name_buff[FN_REFLEN];
int error=1;
DBUG_ENTER("real_open_cached_file");
if ((cache->file=create_temp_file(name_buff, cache->dir, cache->prefix,
(O_RDWR | O_BINARY | O_TRUNC |
O_TEMPORARY | O_SHORT_LIVED),
MYF(MY_WME))) >= 0)
{
error=0;
cache_remove_open_tmp(cache, name_buff);
}
DBUG_RETURN(error);
}
void close_cached_file(IO_CACHE *cache)
{
DBUG_ENTER("close_cached_file");
if (my_b_inited(cache))
{
File file=cache->file;
cache->file= -1; /* Don't flush data */
(void) end_io_cache(cache);
if (file >= 0)
{
(void) my_close(file,MYF(0));
#ifdef CANT_DELETE_OPEN_FILES
if (cache->file_name)
{
(void) my_delete(cache->file_name,MYF(MY_WME | ME_NOINPUT));
my_free(cache->file_name,MYF(0));
}
#endif
}
my_free(cache->dir,MYF(MY_ALLOW_ZERO_PTR));
my_free(cache->prefix,MYF(MY_ALLOW_ZERO_PTR));
}
DBUG_VOID_RETURN;
}