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