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56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/* Copyright (C) 2003 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
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/*
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Handling of multiple key caches
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The idea is to have a thread safe hash on the table name,
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with a default key cache value that is returned if the table name is not in
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the cache.
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*/
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#include <hash.h>
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/*
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Struct to store a key and pointer to object
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*/
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typedef struct st_safe_hash_entry
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{
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uchar *key;
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uint length;
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uchar *data;
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struct st_safe_hash_entry *next, **prev;
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} SAFE_HASH_ENTRY;
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typedef struct st_safe_hash_with_default
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{
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mysql_rwlock_t mutex;
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HASH hash;
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uchar *default_value;
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SAFE_HASH_ENTRY *root;
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} SAFE_HASH;
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my_bool safe_hash_init(SAFE_HASH *hash, uint elements,
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uchar *default_value);
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void safe_hash_free(SAFE_HASH *hash);
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uchar *safe_hash_search(SAFE_HASH *hash, const uchar *key, uint length,
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uchar *def);
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my_bool safe_hash_set(SAFE_HASH *hash, const uchar *key, uint length,
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uchar *data);
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void safe_hash_change(SAFE_HASH *hash, uchar *old_data, uchar *new_data);
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