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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 cache_util.h
+ * @brief Cache Storage Functions
+ *
+ * @defgroup Cache_util Cache Utility Functions
+ * @ingroup MOD_CACHE
+ * @{
+ */
+
+#ifndef CACHE_UTIL_H
+#define CACHE_UTIL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "mod_cache.h"
+
+#include "apr_hooks.h"
+#include "apr.h"
+#include "apr_lib.h"
+#include "apr_strings.h"
+#include "apr_buckets.h"
+#include "apr_md5.h"
+#include "apr_pools.h"
+#include "apr_strings.h"
+#include "apr_optional.h"
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+
+#include "httpd.h"
+#include "http_config.h"
+#include "ap_config.h"
+#include "http_core.h"
+#include "http_protocol.h"
+#include "http_request.h"
+#include "http_vhost.h"
+#include "http_main.h"
+#include "http_log.h"
+#include "http_connection.h"
+#include "util_filter.h"
+#include "apr_uri.h"
+
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+
+#ifdef HAVE_ARPA_INET_H
+#include <arpa/inet.h>
+#endif
+
+#include "apr_atomic.h"
+
+#ifndef MAX
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+#endif
+#ifndef MIN
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+#endif
+
+#define MSEC_ONE_DAY ((apr_time_t)(86400*APR_USEC_PER_SEC)) /* one day, in microseconds */
+#define MSEC_ONE_HR ((apr_time_t)(3600*APR_USEC_PER_SEC)) /* one hour, in microseconds */
+#define MSEC_ONE_MIN ((apr_time_t)(60*APR_USEC_PER_SEC)) /* one minute, in microseconds */
+#define MSEC_ONE_SEC ((apr_time_t)(APR_USEC_PER_SEC)) /* one second, in microseconds */
+
+#define DEFAULT_CACHE_MAXEXPIRE MSEC_ONE_DAY
+#define DEFAULT_CACHE_MINEXPIRE 0
+#define DEFAULT_CACHE_EXPIRE MSEC_ONE_HR
+#define DEFAULT_CACHE_LMFACTOR (0.1)
+#define DEFAULT_CACHE_MAXAGE 5
+#define DEFAULT_X_CACHE 0
+#define DEFAULT_X_CACHE_DETAIL 0
+#define DEFAULT_CACHE_STALE_ON_ERROR 1
+#define DEFAULT_CACHE_LOCKPATH "/mod_cache-lock"
+#define CACHE_LOCKNAME_KEY "mod_cache-lockname"
+#define CACHE_LOCKFILE_KEY "mod_cache-lockfile"
+#define CACHE_CTX_KEY "mod_cache-ctx"
+#define CACHE_SEPARATOR ", \t"
+
+/**
+ * cache_util.c
+ */
+
+struct cache_enable {
+ apr_uri_t url;
+ const char *type;
+ apr_size_t pathlen;
+};
+
+struct cache_disable {
+ apr_uri_t url;
+ apr_size_t pathlen;
+};
+
+/* static information about the local cache */
+typedef struct {
+ apr_array_header_t *cacheenable; /* URLs to cache */
+ apr_array_header_t *cachedisable; /* URLs not to cache */
+ /** store the headers that should not be stored in the cache */
+ apr_array_header_t *ignore_headers;
+ /** store the identifiers that should not be used for key calculation */
+ apr_array_header_t *ignore_session_id;
+ const char *lockpath;
+ apr_time_t lockmaxage;
+ apr_uri_t *base_uri;
+ /** ignore client's requests for uncached responses */
+ unsigned int ignorecachecontrol:1;
+ /** ignore query-string when caching */
+ unsigned int ignorequerystring:1;
+ /** run within the quick handler */
+ unsigned int quick:1;
+ /* thundering herd lock */
+ unsigned int lock:1;
+ unsigned int x_cache:1;
+ unsigned int x_cache_detail:1;
+ /* flag if CacheIgnoreHeader has been set */
+ #define CACHE_IGNORE_HEADERS_SET 1
+ #define CACHE_IGNORE_HEADERS_UNSET 0
+ unsigned int ignore_headers_set:1;
+ /* flag if CacheIgnoreURLSessionIdentifiers has been set */
+ #define CACHE_IGNORE_SESSION_ID_SET 1
+ #define CACHE_IGNORE_SESSION_ID_UNSET 0
+ unsigned int ignore_session_id_set:1;
+ unsigned int base_uri_set:1;
+ unsigned int ignorecachecontrol_set:1;
+ unsigned int ignorequerystring_set:1;
+ unsigned int quick_set:1;
+ unsigned int lock_set:1;
+ unsigned int lockpath_set:1;
+ unsigned int lockmaxage_set:1;
+ unsigned int x_cache_set:1;
+ unsigned int x_cache_detail_set:1;
+} cache_server_conf;
+
+typedef struct {
+ /* Minimum time to keep cached files in msecs */
+ apr_time_t minex;
+ /* Maximum time to keep cached files in msecs */
+ apr_time_t maxex;
+ /* default time to keep cached file in msecs */
+ apr_time_t defex;
+ /* factor for estimating expires date */
+ double factor;
+ /* cache enabled for this location */
+ apr_array_header_t *cacheenable;
+ /* cache disabled for this location */
+ unsigned int disable:1;
+ /* set X-Cache headers */
+ unsigned int x_cache:1;
+ unsigned int x_cache_detail:1;
+ /* serve stale on error */
+ unsigned int stale_on_error:1;
+ /** ignore the last-modified header when deciding to cache this request */
+ unsigned int no_last_mod_ignore:1;
+ /** ignore expiration date from server */
+ unsigned int store_expired:1;
+ /** ignore Cache-Control: private header from server */
+ unsigned int store_private:1;
+ /** ignore Cache-Control: no-store header from client or server */
+ unsigned int store_nostore:1;
+ unsigned int minex_set:1;
+ unsigned int maxex_set:1;
+ unsigned int defex_set:1;
+ unsigned int factor_set:1;
+ unsigned int x_cache_set:1;
+ unsigned int x_cache_detail_set:1;
+ unsigned int stale_on_error_set:1;
+ unsigned int no_last_mod_ignore_set:1;
+ unsigned int store_expired_set:1;
+ unsigned int store_private_set:1;
+ unsigned int store_nostore_set:1;
+ unsigned int enable_set:1;
+ unsigned int disable_set:1;
+} cache_dir_conf;
+
+/* A linked-list of authn providers. */
+typedef struct cache_provider_list cache_provider_list;
+
+struct cache_provider_list {
+ const char *provider_name;
+ const cache_provider *provider;
+ cache_provider_list *next;
+};
+
+/* per request cache information */
+typedef struct {
+ cache_provider_list *providers; /* possible cache providers */
+ const cache_provider *provider; /* current cache provider */
+ const char *provider_name; /* current cache provider name */
+ int fresh; /* is the entity fresh? */
+ cache_handle_t *handle; /* current cache handle */
+ cache_handle_t *stale_handle; /* stale cache handle */
+ apr_table_t *stale_headers; /* original request headers. */
+ int in_checked; /* CACHE_SAVE must cache the entity */
+ int block_response; /* CACHE_SAVE must block response. */
+ apr_bucket_brigade *saved_brigade; /* copy of partial response */
+ apr_off_t saved_size; /* length of saved_brigade */
+ apr_time_t exp; /* expiration */
+ apr_time_t lastmod; /* last-modified time */
+ cache_info *info; /* current cache info */
+ ap_filter_t *save_filter; /* Enable us to restore the filter on error */
+ ap_filter_t *remove_url_filter; /* Enable us to remove the filter */
+ const char *key; /* The cache key created for this
+ * request
+ */
+ apr_off_t size; /* the content length from the headers, or -1 */
+ apr_bucket_brigade *out; /* brigade to reuse for upstream responses */
+ cache_control_t control_in; /* cache control incoming */
+} cache_request_rec;
+
+/**
+ * Check the whether the request allows a cached object to be served as per RFC2616
+ * section 14.9.4 (Cache Revalidation and Reload Controls)
+ * @param cache cache_request_rec
+ * @param r request_rec
+ * @return 0 ==> cache object may not be served, 1 ==> cache object may be served
+ */
+int ap_cache_check_no_cache(cache_request_rec *cache, request_rec *r);
+
+/**
+ * Check the whether the request allows a cached object to be stored as per RFC2616
+ * section 14.9.2 (What May be Stored by Caches)
+ * @param cache cache_request_rec
+ * @param r request_rec
+ * @return 0 ==> cache object may not be served, 1 ==> cache object may be served
+ */
+int ap_cache_check_no_store(cache_request_rec *cache, request_rec *r);
+
+/**
+ * Check the freshness of the cache object per RFC2616 section 13.2 (Expiration Model)
+ * @param h cache_handle_t
+ * @param cache cache_request_rec
+ * @param r request_rec
+ * @return 0 ==> cache object is stale, 1 ==> cache object is fresh
+ */
+int cache_check_freshness(cache_handle_t *h, cache_request_rec *cache,
+ request_rec *r);
+
+/**
+ * Try obtain a cache wide lock on the given cache key.
+ *
+ * If we return APR_SUCCESS, we obtained the lock, and we are clear to
+ * proceed to the backend. If we return APR_EEXISTS, then the lock is
+ * already locked, someone else has gone to refresh the backend data
+ * already, so we must return stale data with a warning in the mean
+ * time. If we return anything else, then something has gone pear
+ * shaped, and we allow the request through to the backend regardless.
+ *
+ * This lock is created from the request pool, meaning that should
+ * something go wrong and the lock isn't deleted on return of the
+ * request headers from the backend for whatever reason, at worst the
+ * lock will be cleaned up when the request is dies or finishes.
+ *
+ * If something goes truly bananas and the lock isn't deleted when the
+ * request dies, the lock will be trashed when its max-age is reached,
+ * or when a request arrives containing a Cache-Control: no-cache. At
+ * no point is it possible for this lock to permanently deny access to
+ * the backend.
+ */
+apr_status_t cache_try_lock(cache_server_conf *conf, cache_request_rec *cache,
+ request_rec *r);
+
+/**
+ * Remove the cache lock, if present.
+ *
+ * First, try to close the file handle, whose delete-on-close should
+ * kill the file. Otherwise, just delete the file by name.
+ *
+ * If no lock name has yet been calculated, do the calculation of the
+ * lock name first before trying to delete the file.
+ *
+ * If an optional bucket brigade is passed, the lock will only be
+ * removed if the bucket brigade contains an EOS bucket.
+ */
+apr_status_t cache_remove_lock(cache_server_conf *conf,
+ cache_request_rec *cache, request_rec *r, apr_bucket_brigade *bb);
+
+cache_provider_list *cache_get_providers(request_rec *r,
+ cache_server_conf *conf);
+
+/**
+ * Get a value from a table, where the table may contain multiple
+ * values for a given key.
+ *
+ * When the table contains a single value, that value is returned
+ * unchanged.
+ *
+ * When the table contains two or more values for a key, all values
+ * for the key are returned, separated by commas.
+ */
+const char *cache_table_getm(apr_pool_t *p, const apr_table_t *t,
+ const char *key);
+
+/**
+ * String tokenizer that ignores separator characters within quoted strings
+ * and escaped characters, as per RFC2616 section 2.2.
+ */
+char *cache_strqtok(char *str, const char *sep, char **last);
+
+/**
+ * Merge err_headers_out into headers_out and add request's Content-Type and
+ * Content-Encoding if available.
+ */
+apr_table_t *cache_merge_headers_out(request_rec *r);
+
+/**
+ * Return whether to use request's path/query from early stage (r->parsed_uri)
+ * or the current/rewritable ones (r->uri/r->args).
+ */
+int cache_use_early_url(request_rec *r);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* !CACHE_UTIL_H */
+/** @} */