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         DFREE_CACHE,
  50 };
  51
  52 /*
  53  * Create a memcache structure. max_size is in bytes, if you set it 0 it will
  54  * not forget anything.
  55  */
  56
  57 struct memcache *memcache_init(TALLOC_CTX *mem_ctx, size_t max_size);
  58
  59 /*
  60  * If you set this global memcache, use it as the default cache when NULL is
  61  * passed to the memcache functions below. This is a workaround for many
  62  * situations where passing the cache everywhere would be a big hassle.
  63  */
  64
  65 void memcache_set_global(struct memcache *cache);
  66
  67 /*
  68  * Add a data blob to the cache
  69  */
  70
  71 void memcache_add(struct memcache *cache, enum memcache_number n,
  72                   DATA_BLOB key, DATA_BLOB value);
  73
  74 /*
  75  * Add a talloc object to the cache. The difference to memcache_add() is that
  76  * when the objects is to be discared, talloc_free is called for it. Also
  77  * talloc_move() ownership of the object to the cache.
  78  *
  79  * Please note that the current implementation has a fixed relationship
  80  * between what cache subtypes store talloc objects and which ones store plain
  81  * blobs. We can fix this, but for now we don't have a mixed use of blobs vs
  82  * talloc objects in the cache types.
  83  */
  84
  85 void memcache_add_talloc(struct memcache *cache, enum memcache_number n,
  86                          DATA_BLOB key, void *ptr);
  87
  88 /*
  89  * Delete an object from the cache
  90  */
  91
  92 void memcache_delete(struct memcache *cache, enum memcache_number n,
  93                      DATA_BLOB key);
  94
  95 /*
  96  * Look up an object from the cache. Memory still belongs to the cache, so
  97  * make a copy of it if needed.
  98  */
  99
 100 bool memcache_lookup(struct memcache *cache, enum memcache_number n,
 101                      DATA_BLOB key, DATA_BLOB *value);
 102
 103 /*
 104  * Look up an object from the cache. Memory still belongs to the cache, so
 105  * make a copy of it if needed.
 106  */
 107
 108 void *memcache_lookup_talloc(struct memcache *cache, enum memcache_number n,
 109                              DATA_BLOB key);
 110
 111 /*
 112  * Flush a complete cache subset.
 113  */
 114
 115 void memcache_flush(struct memcache *cache, enum memcache_number n);
 116
 117 #endif