src/util/disk_cache_os.h

/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#ifndef DISK_CACHE_OS_H
#define DISK_CACHE_OS_H

#include "util/u_queue.h"

#if DETECT_OS_WINDOWS

/* TODO: implement disk cache support on windows */

#else

/* Number of bits to mask off from a cache key to get an index. */
#define CACHE_INDEX_KEY_BITS 16

/* Mask for computing an index from a key. */
#define CACHE_INDEX_KEY_MASK ((1 << CACHE_INDEX_KEY_BITS) - 1)

/* The number of keys that can be stored in the index. */
#define CACHE_INDEX_MAX_KEYS (1 << CACHE_INDEX_KEY_BITS)

struct disk_cache {
   /* The path to the cache directory. */
   char *path;
   bool path_init_failed;

   /* Thread queue for compressing and writing cache entries to disk */
   struct util_queue cache_queue;

   /* Seed for rand, which is used to pick a random directory */
   uint64_t seed_xorshift128plus[2];

   /* A pointer to the mmapped index file within the cache directory. */
   uint8_t *index_mmap;
   size_t index_mmap_size;

   /* Pointer to total size of all objects in cache (within index_mmap) */
   uint64_t *size;

   /* Pointer to stored keys, (within index_mmap). */
   uint8_t *stored_keys;

   /* Maximum size of all cached objects (in bytes). */
   uint64_t max_size;

   /* Driver cache keys. */
   uint8_t *driver_keys_blob;
   size_t driver_keys_blob_size;

   disk_cache_put_cb blob_put_cb;
   disk_cache_get_cb blob_get_cb;
};

char *
disk_cache_generate_cache_dir(void *mem_ctx);

bool
disk_cache_enabled(void);

bool
disk_cache_mmap_cache_index(void *mem_ctx, struct disk_cache *cache,
                            char *path);

void
disk_cache_destroy_mmap(struct disk_cache *cache);

#endif

#endif /* DISK_CACHE_OS_H */