libwebsockets/lib/misc/cache-ttl/private-lib-misc-cache-ttl.h
2021-06-22 15:55:29 +01:00

99 lines
3.2 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2021 Andy Green <andy@warmcat.com>
*
* 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 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.
*/
#define lwsl_cache lwsl_debug
#define lwsl_hexdump_cache lwsl_hexdump_debug
#define LWS_CACHE_MAX_LEVELS 3
/*
* If we need structure inside the cache tag names, use this character as a
* separator
*/
#define LWSCTAG_SEP '|'
/*
* Our synthetic cache result items all have tags starting with this char
*/
#define META_ITEM_LEADING '!'
typedef struct lws_cache_ttl_item_heap {
lws_dll2_t list_expiry;
lws_dll2_t list_lru;
lws_usec_t expiry;
size_t key_len;
size_t size;
/*
* len + key_len + 1 bytes of data overcommitted, user object first
* so it is well-aligned, then the NUL-terminated key name
*/
} lws_cache_ttl_item_heap_t;
/* this is a "base class", all cache implementations have one at the start */
typedef struct lws_cache_ttl_lru {
struct lws_cache_creation_info info;
lws_sorted_usec_list_t sul;
struct lws_cache_ttl_lru *child;
uint64_t current_footprint;
} lws_cache_ttl_lru_t;
/*
* The heap-backed cache uses lws_dll2 linked-lists to track items that are
* in it.
*/
typedef struct lws_cache_ttl_lru_heap {
lws_cache_ttl_lru_t cache;
lws_dll2_owner_t items_expiry;
lws_dll2_owner_t items_lru;
} lws_cache_ttl_lru_t_heap_t;
/*
* We want to be able to work with a large file-backed implementation even on
* devices that don't have heap to track what is in it. It means if lookups
* reach this cache layer, we will be scanning a potentially large file.
*
* L1 caching of lookups (including null result list) reduces the expense of
* this on average. We keep a copy of the last computed earliest expiry.
*
* We can't keep an open file handle here. Because other processes may change
* the cookie file by deleting and replacing it, we have to open it fresh each
* time.
*/
typedef struct lws_cache_nscookiejar {
lws_cache_ttl_lru_t cache;
lws_usec_t earliest_expiry;
} lws_cache_nscookiejar_t;
void
lws_cache_clear_matches(lws_dll2_owner_t *results_owner);
void
lws_cache_schedule(struct lws_cache_ttl_lru *cache, sul_cb_t cb, lws_usec_t e);