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/* Copyright (C) 2003-2007 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., 51 Franklin Street, 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 "maria_def.h"
#include "ma_pagecache.h"
#include <hash.h>
#include <m_string.h>
#include "../../mysys/my_safehash.h"
/*****************************************************************************
Functions to handle the pagecache objects
*****************************************************************************/
/* Variable to store all key cache objects */
static SAFE_HASH pagecache_hash;
my_bool multi_pagecache_init(void)
{
return safe_hash_init(&pagecache_hash, 16, (uchar*) maria_pagecache);
}
void multi_pagecache_free(void)
{
safe_hash_free(&pagecache_hash);
}
/*
Get a key cache to be used for a specific table.
SYNOPSIS
multi_pagecache_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_pagecache_init.
This will ensure that it works with old MyISAM clients.
RETURN
key cache to use
*/
PAGECACHE *multi_pagecache_search(uchar *key, uint length,
PAGECACHE *def)
{
if (!pagecache_hash.hash.records)
return def;
return (PAGECACHE*) safe_hash_search(&pagecache_hash, key, length,
(void*) def);
}
/*
Assosiate a key cache with a key
SYONOPSIS
multi_pagecache_set()
key key (path to table etc..)
length Length of key
pagecache 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_pagecache_set(const uchar *key, uint length,
PAGECACHE *pagecache)
{
return safe_hash_set(&pagecache_hash, key, length, (uchar*) pagecache);
}
void multi_pagecache_change(PAGECACHE *old_data,
PAGECACHE *new_data)
{
safe_hash_change(&pagecache_hash, (uchar*) old_data, (uchar*) new_data);
}
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