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/* 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*/
/** @} */