src/util/disk_cache.h

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #ifndef DISK_CACHE_H
  25 #define DISK_CACHE_H
  26
  27 #include <stdint.h>
  28 #include <stdbool.h>
  29
  30 #ifdef __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 /* Size of cache keys in bytes. */
  35 #define CACHE_KEY_SIZE 20
  36
  37 typedef uint8_t cache_key[CACHE_KEY_SIZE];
  38
  39 struct disk_cache;
  40
  41 /* Provide inlined stub functions if the shader cache is disabled. */
  42
  43 #ifdef ENABLE_SHADER_CACHE
  44
  45 /**
  46  * Create a new cache object.
  47  *
  48  * This function creates the handle necessary for all subsequent cache_*
  49  * functions.
  50  *
  51  * This cache provides two distinct operations:
  52  *
  53  *   o Storage and retrieval of arbitrary objects by cryptographic
  54  *     name (or "key").  This is provided via disk_cache_put() and
  55  *     disk_cache_get().
  56  *
  57  *   o The ability to store a key alone and check later whether the
  58  *     key was previously stored. This is provided via disk_cache_put_key()
  59  *     and disk_cache_has_key().
  60  *
  61  * The put_key()/has_key() operations are conceptually identical to
  62  * put()/get() with no data, but are provided separately to allow for
  63  * a more efficient implementation.
  64  *
  65  * In all cases, the keys are sequences of 20 bytes. It is anticipated
  66  * that callers will compute appropriate SHA-1 signatures for keys,
  67  * (though nothing in this implementation directly relies on how the
  68  * names are computed). See mesa-sha1.h and _mesa_sha1_compute for
  69  * assistance in computing SHA-1 signatures.
  70  */
  71 struct disk_cache *
  72 disk_cache_create(void);
  73
  74 /**
  75  * Destroy a cache object, (freeing all associated resources).
  76  */
  77 void
  78 disk_cache_destroy(struct disk_cache *cache);
  79
  80 /**
  81  * Store an item in the cache under the name \key.
  82  *
  83  * The item can be retrieved later with disk_cache_get(), (unless the item has
  84  * been evicted in the interim).
  85  *
  86  * Any call to disk_cache_put() may cause an existing, random item to be
  87  * evicted from the cache.
  88  */
  89 void
  90 disk_cache_put(struct disk_cache *cache, cache_key key,
  91                const void *data, size_t size);
  92
  93 /**
  94  * Retrieve an item previously stored in the cache with the name <key>.
  95  *
  96  * The item must have been previously stored with a call to disk_cache_put().
  97  *
  98  * If \size is non-NULL, then, on successful return, it will be set to the
  99  * size of the object.
 100  *
 101  * \return A pointer to the stored object if found. NULL if the object
 102  * is not found, or if any error occurs, (memory allocation failure,
 103  * filesystem error, etc.). The returned data is malloc'ed so the
 104  * caller should call free() it when finished.
 105  */
 106 void *
 107 disk_cache_get(struct disk_cache *cache, cache_key key, size_t *size);
 108
 109 /**
 110  * Store the name \key within the cache, (without any associated data).
 111  *
 112  * Later this key can be checked with disk_cache_has_key(), (unless the key
 113  * has been evicted in the interim).
 114  *
 115  * Any call to cache_record() may cause an existing, random key to be
 116  * evicted from the cache.
 117  */
 118 void
 119 disk_cache_put_key(struct disk_cache *cache, cache_key key);
 120
 121 /**
 122  * Test whether the name \key was previously recorded in the cache.
 123  *
 124  * Return value: True if disk_cache_put_key() was previously called with
 125  * \key, (and the key was not evicted in the interim).
 126  *
 127  * Note: disk_cache_has_key() will only return true for keys passed to
 128  * disk_cache_put_key(). Specifically, a call to disk_cache_put() will not cause
 129  * disk_cache_has_key() to return true for the same key.
 130  */
 131 bool
 132 disk_cache_has_key(struct disk_cache *cache, cache_key key);
 133
 134 #else
 135
 136 static inline struct disk_cache *
 137 disk_cache_create(void)
 138 {
 139    return NULL;
 140 }
 141
 142 static inline void
 143 disk_cache_destroy(struct disk_cache *cache) {
 144    return;
 145 }
 146
 147 static inline void
 148 disk_cache_put(struct disk_cache *cache, cache_key key,
 149           const void *data, size_t size)
 150 {
 151    return;
 152 }
 153
 154 static inline uint8_t *
 155 disk_cache_get(struct disk_cache *cache, cache_key key, size_t *size)
 156 {
 157    return NULL;
 158 }
 159
 160 static inline void
 161 disk_cache_put_key(struct disk_cache *cache, cache_key key)
 162 {
 163    return;
 164 }
 165
 166 static inline bool
 167 disk_cache_has_key(struct disk_cache *cache, cache_key key)
 168 {
 169    return false;
 170 }
 171
 172 #endif /* ENABLE_SHADER_CACHE */
 173
 174 #ifdef __cplusplus
 175 }
 176 #endif
 177
 178 #endif /* CACHE_H */