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Diffstat (limited to 'modules/cache/mod_cache.h')
| -rw-r--r-- | modules/cache/mod_cache.h | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/modules/cache/mod_cache.h b/modules/cache/mod_cache.h new file mode 100644 index 0000000..53e80c0 --- /dev/null +++ b/modules/cache/mod_cache.h @@ -0,0 +1,192 @@ +/* Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/** + * @file mod_cache.h + * @brief Main include file for the Apache Transparent Cache + * + * @defgroup MOD_CACHE mod_cache + * @ingroup APACHE_MODS + * @{ + */ + +#ifndef MOD_CACHE_H +#define MOD_CACHE_H + +#include "httpd.h" +#include "apr_date.h" +#include "apr_optional.h" +#include "apr_hooks.h" + +#include "cache_common.h" + +/* Create a set of CACHE_DECLARE(type), CACHE_DECLARE_NONSTD(type) and + * CACHE_DECLARE_DATA with appropriate export and import tags for the platform + */ +#if !defined(WIN32) +#define CACHE_DECLARE(type) type +#define CACHE_DECLARE_NONSTD(type) type +#define CACHE_DECLARE_DATA +#elif defined(CACHE_DECLARE_STATIC) +#define CACHE_DECLARE(type) type __stdcall +#define CACHE_DECLARE_NONSTD(type) type +#define CACHE_DECLARE_DATA +#elif defined(CACHE_DECLARE_EXPORT) +#define CACHE_DECLARE(type) __declspec(dllexport) type __stdcall +#define CACHE_DECLARE_NONSTD(type) __declspec(dllexport) type +#define CACHE_DECLARE_DATA __declspec(dllexport) +#else +#define CACHE_DECLARE(type) __declspec(dllimport) type __stdcall +#define CACHE_DECLARE_NONSTD(type) __declspec(dllimport) type +#define CACHE_DECLARE_DATA __declspec(dllimport) +#endif + +/* cache info information */ +typedef struct cache_info cache_info; +struct cache_info { + /** + * the original time corresponding to the 'Date:' header of the request + * served + */ + apr_time_t date; + /** a time when the cached entity is due to expire */ + apr_time_t expire; + /** r->request_time from the same request */ + apr_time_t request_time; + /** apr_time_now() at the time the entity was actually cached */ + apr_time_t response_time; + /** + * HTTP status code of the cached entity. Though not necessarily the + * status code finally issued to the request. + */ + int status; + /* cached cache-control */ + cache_control_t control; +}; + +/* cache handle information */ +typedef struct cache_object cache_object_t; +struct cache_object { + const char *key; + cache_object_t *next; + cache_info info; + /* Opaque portion (specific to the implementation) of the cache object */ + void *vobj; +}; + +typedef struct cache_handle cache_handle_t; +struct cache_handle { + cache_object_t *cache_obj; + apr_table_t *req_hdrs; /* cached request headers */ + apr_table_t *resp_hdrs; /* cached response headers */ +}; + +#define CACHE_PROVIDER_GROUP "cache" + +typedef struct { + int (*remove_entity) (cache_handle_t *h); + apr_status_t (*store_headers)(cache_handle_t *h, request_rec *r, cache_info *i); + apr_status_t (*store_body)(cache_handle_t *h, request_rec *r, apr_bucket_brigade *in, + apr_bucket_brigade *out); + apr_status_t (*recall_headers) (cache_handle_t *h, request_rec *r); + apr_status_t (*recall_body) (cache_handle_t *h, apr_pool_t *p, apr_bucket_brigade *bb); + int (*create_entity) (cache_handle_t *h, request_rec *r, + const char *urlkey, apr_off_t len, apr_bucket_brigade *bb); + int (*open_entity) (cache_handle_t *h, request_rec *r, + const char *urlkey); + int (*remove_url) (cache_handle_t *h, request_rec *r); + apr_status_t (*commit_entity)(cache_handle_t *h, request_rec *r); + apr_status_t (*invalidate_entity)(cache_handle_t *h, request_rec *r); +} cache_provider; + +typedef enum { + AP_CACHE_HIT, + AP_CACHE_REVALIDATE, + AP_CACHE_MISS, + AP_CACHE_INVALIDATE +} ap_cache_status_e; + +#define AP_CACHE_HIT_ENV "cache-hit" +#define AP_CACHE_REVALIDATE_ENV "cache-revalidate" +#define AP_CACHE_MISS_ENV "cache-miss" +#define AP_CACHE_INVALIDATE_ENV "cache-invalidate" +#define AP_CACHE_STATUS_ENV "cache-status" + + +/* cache_util.c */ +/* do a HTTP/1.1 age calculation */ +CACHE_DECLARE(apr_time_t) ap_cache_current_age(cache_info *info, const apr_time_t age_value, + apr_time_t now); + +CACHE_DECLARE(apr_time_t) ap_cache_hex2usec(const char *x); +CACHE_DECLARE(void) ap_cache_usec2hex(apr_time_t j, char *y); +CACHE_DECLARE(char *) ap_cache_generate_name(apr_pool_t *p, int dirlevels, + int dirlength, + const char *name); +CACHE_DECLARE(const char *)ap_cache_tokstr(apr_pool_t *p, const char *list, const char **str); + +/* Create a new table consisting of those elements from an + * headers table that are allowed to be stored in a cache. + */ +CACHE_DECLARE(apr_table_t *)ap_cache_cacheable_headers(apr_pool_t *pool, + apr_table_t *t, + server_rec *s); + +/* Create a new table consisting of those elements from an input + * headers table that are allowed to be stored in a cache. + */ +CACHE_DECLARE(apr_table_t *)ap_cache_cacheable_headers_in(request_rec *r); + +/* Create a new table consisting of those elements from an output + * headers table that are allowed to be stored in a cache; + * ensure there is a content type and capture any errors. + */ +CACHE_DECLARE(apr_table_t *)ap_cache_cacheable_headers_out(request_rec *r); + +/** + * Parse the Cache-Control and Pragma headers in one go, marking + * which tokens appear within the header. Populate the structure + * passed in. + */ +int ap_cache_control(request_rec *r, cache_control_t *cc, const char *cc_header, + const char *pragma_header, apr_table_t *headers); + + +/* hooks */ + +/** + * Cache status hook. + * This hook is called as soon as the cache has made a decision as to whether + * an entity should be served from cache (hit), should be served from cache + * after a successful validation (revalidate), or served from the backend + * and potentially cached (miss). + * + * A basic implementation of this hook exists in mod_cache which writes this + * information to the subprocess environment, and optionally to request + * headers. Further implementations may add hooks as appropriate to perform + * more advanced processing, or to store statistics about the cache behaviour. + */ +APR_DECLARE_EXTERNAL_HOOK(cache, CACHE, int, cache_status, (cache_handle_t *h, + request_rec *r, apr_table_t *headers, ap_cache_status_e status, + const char *reason)) + +APR_DECLARE_OPTIONAL_FN(apr_status_t, + ap_cache_generate_key, + (request_rec *r, apr_pool_t*p, const char **key)); + + +#endif /*MOD_CACHE_H*/ +/** @} */ |