source/include/memcache.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3    In-memory cache
   4    Copyright (C) Volker Lendecke 2007-2008
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #ifndef __MEMCACHE_H__
  21 #define __MEMCACHE_H__
  22
  23 #include "includes.h"
  24
  25 struct memcache;
  26
  27 /*
  28  * A memcache can store different subkeys with overlapping keys, the
  29  * memcache_number becomes part of the key. Feel free to add caches of your
  30  * own here.
  31  *
  32  * If you add talloc type caches, also note this in the switch statement in
  33  * memcache_is_talloc().
  34  */
  35
  36 enum memcache_number {
  37         STAT_CACHE,
  38         UID_SID_CACHE,
  39         SID_UID_CACHE,
  40         GID_SID_CACHE,
  41         SID_GID_CACHE,
  42         GETWD_CACHE,
  43         GETPWNAM_CACHE,         /* talloc */
  44         MANGLE_HASH2_CACHE,
  45         PDB_GETPWSID_CACHE,     /* talloc */
  46         SINGLETON_CACHE_TALLOC, /* talloc */
  47         SINGLETON_CACHE
  48 };
  49
  50 /*
  51  * Create a memcache structure. max_size is in bytes, if you set it 0 it will
  52  * not forget anything.
  53  */
  54
  55 struct memcache *memcache_init(TALLOC_CTX *mem_ctx, size_t max_size);
  56
  57 /*
  58  * If you set this global memcache, use it as the default cache when NULL is
  59  * passed to the memcache functions below. This is a workaround for many
  60  * situations where passing the cache everywhere would be a big hassle.
  61  */
  62
  63 void memcache_set_global(struct memcache *cache);
  64
  65 /*
  66  * Add a data blob to the cache
  67  */
  68
  69 void memcache_add(struct memcache *cache, enum memcache_number n,
  70                   DATA_BLOB key, DATA_BLOB value);
  71
  72 /*
  73  * Add a talloc object to the cache. The difference to memcache_add() is that
  74  * when the objects is to be discared, talloc_free is called for it. Also
  75  * talloc_move() ownership of the object to the cache.
  76  *
  77  * Please note that the current implementation has a fixed relationship
  78  * between what cache subtypes store talloc objects and which ones store plain
  79  * blobs. We can fix this, but for now we don't have a mixed use of blobs vs
  80  * talloc objects in the cache types.
  81  */
  82
  83 void memcache_add_talloc(struct memcache *cache, enum memcache_number n,
  84                          DATA_BLOB key, void *ptr);
  85
  86 /*
  87  * Delete an object from the cache
  88  */
  89
  90 void memcache_delete(struct memcache *cache, enum memcache_number n,
  91                      DATA_BLOB key);
  92
  93 /*
  94  * Look up an object from the cache. Memory still belongs to the cache, so
  95  * make a copy of it if needed.
  96  */
  97
  98 bool memcache_lookup(struct memcache *cache, enum memcache_number n,
  99                      DATA_BLOB key, DATA_BLOB *value);
 100
 101 /*
 102  * Look up an object from the cache. Memory still belongs to the cache, so
 103  * make a copy of it if needed.
 104  */
 105
 106 void *memcache_lookup_talloc(struct memcache *cache, enum memcache_number n,
 107                              DATA_BLOB key);
 108
 109 /*
 110  * Flush a complete cache subset.
 111  */
 112
 113 void memcache_flush(struct memcache *cache, enum memcache_number n);
 114
 115 #endif