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/* Copyright (C) 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 <drizzled/mysql_priv.h>
#include "ha_blackhole.h"
/* Static declarations for handlerton */
static handler *blackhole_create_handler(handlerton *hton,
TABLE_SHARE *table,
MEM_ROOT *mem_root)
{
return new (mem_root) ha_blackhole(hton, table);
}
/* Static declarations for shared structures */
static pthread_mutex_t blackhole_mutex;
static HASH blackhole_open_tables;
static st_blackhole_share *get_share(const char *table_name);
static void free_share(st_blackhole_share *share);
/*****************************************************************************
** BLACKHOLE tables
*****************************************************************************/
ha_blackhole::ha_blackhole(handlerton *hton,
TABLE_SHARE *table_arg)
:handler(hton, table_arg)
{}
static const char *ha_blackhole_exts[] = {
NullS
};
const char **ha_blackhole::bas_ext() const
{
return ha_blackhole_exts;
}
int ha_blackhole::open(const char *name, int mode __attribute__((unused)),
uint test_if_locked __attribute__((unused)))
{
if (!(share= get_share(name)))
return(HA_ERR_OUT_OF_MEM);
thr_lock_data_init(&share->lock, &lock, NULL);
return(0);
}
int ha_blackhole::close(void)
{
free_share(share);
return(0);
}
int ha_blackhole::create(const char *name __attribute__((unused)),
TABLE *table_arg __attribute__((unused)),
HA_CREATE_INFO *create_info __attribute__((unused)))
{
return(0);
}
const char *ha_blackhole::index_type(uint key_number __attribute__((unused)))
{
return("BTREE");
}
int ha_blackhole::write_row(uchar * buf __attribute__((unused)))
{
return(table->next_number_field ? update_auto_increment() : 0);
}
int ha_blackhole::rnd_init(bool scan __attribute__((unused)))
{
return(0);
}
int ha_blackhole::rnd_next(uchar *buf __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::rnd_pos(uchar * buf __attribute__((unused)),
uchar *pos __attribute__((unused)))
{
assert(0);
return(0);
}
void ha_blackhole::position(const uchar *record __attribute__((unused)))
{
assert(0);
return;
}
int ha_blackhole::info(uint flag)
{
memset(&stats, 0, sizeof(stats));
if (flag & HA_STATUS_AUTO)
stats.auto_increment_value= 1;
return(0);
}
int ha_blackhole::external_lock(THD *thd __attribute__((unused)),
int lock_type __attribute__((unused)))
{
return(0);
}
THR_LOCK_DATA **ha_blackhole::store_lock(THD *thd,
THR_LOCK_DATA **to,
enum thr_lock_type lock_type)
{
if (lock_type != TL_IGNORE && lock.type == TL_UNLOCK)
{
/*
Here is where we get into the guts of a row level lock.
If TL_UNLOCK is set
If we are not doing a LOCK TABLE or DISCARD/IMPORT
TABLESPACE, then allow multiple writers
*/
if ((lock_type >= TL_WRITE_CONCURRENT_INSERT &&
lock_type <= TL_WRITE) && !thd_in_lock_tables(thd)
&& !thd_tablespace_op(thd))
lock_type = TL_WRITE_ALLOW_WRITE;
/*
In queries of type INSERT INTO t1 SELECT ... FROM t2 ...
MySQL would use the lock TL_READ_NO_INSERT on t2, and that
would conflict with TL_WRITE_ALLOW_WRITE, blocking all inserts
to t2. Convert the lock to a normal read lock to allow
concurrent inserts to t2.
*/
if (lock_type == TL_READ_NO_INSERT && !thd_in_lock_tables(thd))
lock_type = TL_READ;
lock.type= lock_type;
}
*to++= &lock;
return(to);
}
int ha_blackhole::index_read_map(uchar * buf __attribute__((unused)),
const uchar * key __attribute__((unused)),
key_part_map keypart_map __attribute__((unused)),
enum ha_rkey_function find_flag __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::index_read_idx_map(uchar * buf __attribute__((unused)),
uint idx __attribute__((unused)),
const uchar * key __attribute__((unused)),
key_part_map keypart_map __attribute__((unused)),
enum ha_rkey_function find_flag __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::index_read_last_map(uchar * buf __attribute__((unused)),
const uchar * key __attribute__((unused)),
key_part_map keypart_map __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::index_next(uchar * buf __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::index_prev(uchar * buf __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::index_first(uchar * buf __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
int ha_blackhole::index_last(uchar * buf __attribute__((unused)))
{
return(HA_ERR_END_OF_FILE);
}
static st_blackhole_share *get_share(const char *table_name)
{
st_blackhole_share *share;
uint length;
length= (uint) strlen(table_name);
pthread_mutex_lock(&blackhole_mutex);
if (!(share= (st_blackhole_share*) hash_search(&blackhole_open_tables,
(uchar*) table_name, length)))
{
if (!(share= (st_blackhole_share*) my_malloc(sizeof(st_blackhole_share) +
length,
MYF(MY_WME | MY_ZEROFILL))))
goto error;
share->table_name_length= length;
strmov(share->table_name, table_name);
if (my_hash_insert(&blackhole_open_tables, (uchar*) share))
{
my_free((uchar*) share, MYF(0));
share= NULL;
goto error;
}
thr_lock_init(&share->lock);
}
share->use_count++;
error:
pthread_mutex_unlock(&blackhole_mutex);
return share;
}
static void free_share(st_blackhole_share *share)
{
pthread_mutex_lock(&blackhole_mutex);
if (!--share->use_count)
hash_delete(&blackhole_open_tables, (uchar*) share);
pthread_mutex_unlock(&blackhole_mutex);
}
static void blackhole_free_key(st_blackhole_share *share)
{
thr_lock_delete(&share->lock);
my_free((uchar*) share, MYF(0));
}
static uchar* blackhole_get_key(st_blackhole_share *share, size_t *length,
my_bool not_used __attribute__((unused)))
{
*length= share->table_name_length;
return (uchar*) share->table_name;
}
static int blackhole_init(void *p)
{
handlerton *blackhole_hton;
blackhole_hton= (handlerton *)p;
blackhole_hton->state= SHOW_OPTION_YES;
blackhole_hton->db_type= DB_TYPE_BLACKHOLE_DB;
blackhole_hton->create= blackhole_create_handler;
blackhole_hton->flags= HTON_CAN_RECREATE;
VOID(pthread_mutex_init(&blackhole_mutex, MY_MUTEX_INIT_FAST));
(void) hash_init(&blackhole_open_tables, system_charset_info,32,0,0,
(hash_get_key) blackhole_get_key,
(hash_free_key) blackhole_free_key, 0);
return 0;
}
static int blackhole_fini(void *p __attribute__((unused)))
{
hash_free(&blackhole_open_tables);
pthread_mutex_destroy(&blackhole_mutex);
return 0;
}
mysql_declare_plugin(blackhole)
{
MYSQL_STORAGE_ENGINE_PLUGIN,
"BLACKHOLE",
"1.0",
"MySQL AB",
"/dev/null storage engine (anything you write to it disappears)",
PLUGIN_LICENSE_GPL,
blackhole_init, /* Plugin Init */
blackhole_fini, /* Plugin Deinit */
NULL, /* status variables */
NULL, /* system variables */
NULL /* config options */
}
mysql_declare_plugin_end;
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