lib/util/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 <talloc.h>
  24 #include "lib/util/data_blob.h"
  25
  26 struct memcache;
  27
  28 /*
  29  * A memcache can store different subkeys with overlapping keys, the
  30  * memcache_number becomes part of the key. Feel free to add caches of your
  31  * own here.
  32  *
  33  * If you add talloc type caches, also note this in the switch statement in
  34  * memcache_is_talloc().
  35  */
  36
  37 enum memcache_number {
  38         STAT_CACHE,
  39         GENCACHE_RAM,
  40         GETWD_CACHE,
  41         GETPWNAM_CACHE,         /* talloc */
  42         MANGLE_HASH2_CACHE,
  43         PDB_GETPWSID_CACHE,     /* talloc */
  44         SINGLETON_CACHE_TALLOC, /* talloc */
  45         SINGLETON_CACHE,
  46         SMB1_SEARCH_OFFSET_MAP,
  47         SHARE_MODE_LOCK_CACHE,  /* talloc */
  48         VIRUSFILTER_SCAN_RESULTS_CACHE_TALLOC /* talloc */
  49 };
  50
  51 /*
  52  * Create a memcache structure. max_size is in bytes, if you set it 0 it will
  53  * not forget anything.
  54  */
  55
  56 struct memcache *memcache_init(TALLOC_CTX *mem_ctx, size_t max_size);
  57
  58 /*
  59  * If you set this global memcache, use it as the default cache when NULL is
  60  * passed to the memcache functions below. This is a workaround for many
  61  * situations where passing the cache everywhere would be a big hassle.
  62  */
  63
  64 void memcache_set_global(struct memcache *cache);
  65
  66 /*
  67  * Add a data blob to the cache
  68  */
  69
  70 void memcache_add(struct memcache *cache, enum memcache_number n,
  71                   DATA_BLOB key, DATA_BLOB value);
  72
  73 /*
  74  * Add a talloc object to the cache. The difference to memcache_add() is that
  75  * when the objects is to be discared, talloc_free is called for it. Also
  76  * talloc_move() ownership of the object to the cache.
  77  *
  78  * Please note that the current implementation has a fixed relationship
  79  * between what cache subtypes store talloc objects and which ones store plain
  80  * blobs. We can fix this, but for now we don't have a mixed use of blobs vs
  81  * talloc objects in the cache types.
  82  */
  83
  84 void memcache_add_talloc(struct memcache *cache, enum memcache_number n,
  85                          DATA_BLOB key, void *ptr);
  86
  87 /*
  88  * Delete an object from the cache
  89  */
  90
  91 void memcache_delete(struct memcache *cache, enum memcache_number n,
  92                      DATA_BLOB key);
  93
  94 /*
  95  * Look up an object from the cache. Memory still belongs to the cache, so
  96  * make a copy of it if needed.
  97  */
  98
  99 bool memcache_lookup(struct memcache *cache, enum memcache_number n,
 100                      DATA_BLOB key, DATA_BLOB *value);
 101
 102 /*
 103  * Look up an object from the cache. Memory still belongs to the cache, so
 104  * make a copy of it if needed.
 105  */
 106
 107 void *memcache_lookup_talloc(struct memcache *cache, enum memcache_number n,
 108                              DATA_BLOB key);
 109
 110 /*
 111  * Flush a complete cache subset.
 112  */
 113
 114 void memcache_flush(struct memcache *cache, enum memcache_number n);
 115
 116 #endif