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/* Copyright (c) 2003, 2011, Oracle and/or its affiliates.
Copyright (c) 2010, 2011, Monty Program 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
/*
Handling of multiple key caches
The idea is to have a thread safe hash on the table name,
with a default key cache value that is returned if the table name is not in
the cache.
*/
#include "mysys_priv.h"
#include <keycache.h>
#include <hash.h>
#include <m_string.h>
#include "my_safehash.h"
/*****************************************************************************
Functions to handle the key cache objects
*****************************************************************************/
/* Variable to store all key cache objects */
static SAFE_HASH key_cache_hash;
my_bool multi_keycache_init(void)
{
return safe_hash_init(&key_cache_hash, 16, (uchar*) dflt_key_cache);
}
void multi_keycache_free(void)
{
safe_hash_free(&key_cache_hash);
}
/*
Get a key cache to be used for a specific table.
SYNOPSIS
multi_key_cache_search()
key key to find (usually table path)
uint length Length of key.
def Default value if no key cache
NOTES
This function is coded in such a way that we will return the
default key cache even if one never called multi_keycache_init.
This will ensure that it works with old MyISAM clients.
RETURN
key cache to use
*/
KEY_CACHE *multi_key_cache_search(uchar *key, uint length,
KEY_CACHE *def)
{
if (!key_cache_hash.hash.records)
return def;
return (KEY_CACHE*) safe_hash_search(&key_cache_hash, key, length,
(void*) def);
}
/*
Assosiate a key cache with a key
SYONOPSIS
multi_key_cache_set()
key key (path to table etc..)
length Length of key
key_cache cache to assococite with the table
NOTES
This can be used both to insert a new entry and change an existing
entry
*/
my_bool multi_key_cache_set(const uchar *key, uint length,
KEY_CACHE *key_cache)
{
return safe_hash_set(&key_cache_hash, key, length, (uchar*) key_cache);
}
void multi_key_cache_change(KEY_CACHE *old_data,
KEY_CACHE *new_data)
{
safe_hash_change(&key_cache_hash, (uchar*) old_data, (uchar*) new_data);
}
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