1 /* 2 * libwebsockets - small server side websockets and web server implementation 3 * 4 * Copyright (C) 2010 - 2021 Andy Green <andy@warmcat.com> 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to 8 * deal in the Software without restriction, including without limitation the 9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 22 * IN THE SOFTWARE. 23 */ 24 25 #define lwsl_cache lwsl_debug 26 #define lwsl_hexdump_cache lwsl_hexdump_debug 27 28 #define LWS_CACHE_MAX_LEVELS 3 29 30 /* 31 * If we need structure inside the cache tag names, use this character as a 32 * separator 33 */ 34 #define LWSCTAG_SEP '|' 35 36 /* 37 * Our synthetic cache result items all have tags starting with this char 38 */ 39 #define META_ITEM_LEADING '!' 40 41 typedef struct lws_cache_ttl_item_heap { 42 lws_dll2_t list_expiry; 43 lws_dll2_t list_lru; 44 45 lws_usec_t expiry; 46 size_t key_len; 47 size_t size; 48 49 /* 50 * len + key_len + 1 bytes of data overcommitted, user object first 51 * so it is well-aligned, then the NUL-terminated key name 52 */ 53 } lws_cache_ttl_item_heap_t; 54 55 /* this is a "base class", all cache implementations have one at the start */ 56 57 typedef struct lws_cache_ttl_lru { 58 struct lws_cache_creation_info info; 59 lws_sorted_usec_list_t sul; 60 struct lws_cache_ttl_lru *child; 61 uint64_t current_footprint; 62 } lws_cache_ttl_lru_t; 63 64 /* 65 * The heap-backed cache uses lws_dll2 linked-lists to track items that are 66 * in it. 67 */ 68 69 typedef struct lws_cache_ttl_lru_heap { 70 lws_cache_ttl_lru_t cache; 71 72 lws_dll2_owner_t items_expiry; 73 lws_dll2_owner_t items_lru; 74 } lws_cache_ttl_lru_t_heap_t; 75 76 /* 77 * We want to be able to work with a large file-backed implementation even on 78 * devices that don't have heap to track what is in it. It means if lookups 79 * reach this cache layer, we will be scanning a potentially large file. 80 * 81 * L1 caching of lookups (including null result list) reduces the expense of 82 * this on average. We keep a copy of the last computed earliest expiry. 83 * 84 * We can't keep an open file handle here. Because other processes may change 85 * the cookie file by deleting and replacing it, we have to open it fresh each 86 * time. 87 */ 88 typedef struct lws_cache_nscookiejar { 89 lws_cache_ttl_lru_t cache; 90 91 lws_usec_t earliest_expiry; 92 } lws_cache_nscookiejar_t; 93 94 void 95 lws_cache_clear_matches(lws_dll2_owner_t *results_owner); 96 97 void 98 lws_cache_schedule(struct lws_cache_ttl_lru *cache, sul_cb_t cb, lws_usec_t e); 99