Backport all of experimental mod_cache, mod_disk_cache and mod_mem_cache changes from 2.1 (fc4a822c) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

CHANGES

+3 −0

Changes for CHANGES: 3 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		Changes with Apache 2.0.51
		*) Backport all mod_cache, mod_mem_cache, mod_disk_cache and
		related cache utilities from the Apache 2.1 branch.
		[Bill Stoddard]

		*) mod_autoindex: Don't truncate the directory listing if a stat()
		call fails (for instance on a >2Gb file). PR 17357.

modules/experimental/cache_storage.c

+30 −83

Changes for modules/experimental/cache_storage.c: 30 added lines, 83 removed lines.
Original line number	Diff line number	Diff line
		@@ -17,12 +17,6 @@

		#include "mod_cache.h"

		APR_HOOK_STRUCT(
		APR_HOOK_LINK(remove_url)
		APR_HOOK_LINK(create_entity)
		APR_HOOK_LINK(open_entity)
		)

		extern APR_OPTIONAL_FN_TYPE(ap_cache_generate_key) *cache_generate_key;

		extern module AP_MODULE_DECLARE_DATA cache_module;
		@@ -33,22 +27,25 @@ extern module AP_MODULE_DECLARE_DATA cache_module;
		* delete all URL entities from the cache
		*
		*/
		int cache_remove_url(request_rec r, const char types, char *url)
		int cache_remove_url(request_rec r, char url)
		{
		const char *next = types;
		const char *type;
		cache_provider_list *list;
		apr_status_t rv;
		char *key;
		cache_request_rec cache = (cache_request_rec )
		ap_get_module_config(r->request_config, &cache_module);

		rv = cache_generate_key(r,r->pool,&key);
		if (rv != APR_SUCCESS) {
		return rv;
		}

		list = cache->providers;

		/* for each specified cache type, delete the URL */
		while(next) {
		type = ap_cache_tokstr(r->pool, next, &next);
		cache_run_remove_url(type, key);
		while(list) {
		list->provider->remove_url(key);
		list = list->next;
		}
		return OK;
		}
		@@ -65,11 +62,10 @@ int cache_remove_url(request_rec r, const char types, char *url)
		* decide whether or not it wants to cache this particular entity.
		* If the size is unknown, a size of -1 should be set.
		*/
		int cache_create_entity(request_rec r, const char types, char *url, apr_off_t size)
		int cache_create_entity(request_rec r, char url, apr_off_t size)
		{
		cache_provider_list *list;
		cache_handle_t *h = apr_pcalloc(r->pool, sizeof(cache_handle_t));
		const char *next = types;
		const char *type;
		char *key;
		apr_status_t rv;
		cache_request_rec cache = (cache_request_rec )
		@@ -79,15 +75,19 @@ int cache_create_entity(request_rec r, const char types, char *url, apr_off_t
		if (rv != APR_SUCCESS) {
		return rv;
		}

		list = cache->providers;
		/* for each specified cache type, delete the URL */
		while (next) {
		type = ap_cache_tokstr(r->pool, next, &next);
		switch (rv = cache_run_create_entity(h, r, type, key, size)) {
		while (list) {
		switch (rv = list->provider->create_entity(h, r, key, size)) {
		case OK: {
		cache->handle = h;
		cache->provider = list->provider;
		cache->provider_name = list->provider_name;
		return OK;
		}
		case DECLINED: {
		list = list->next;
		continue;
		}
		default: {
		@@ -98,19 +98,6 @@ int cache_create_entity(request_rec r, const char types, char *url, apr_off_t
		return DECLINED;
		}

		/*
		* remove a specific URL entity from the cache
		*
		* The specific entity referenced by the cache_handle is removed
		* from the cache, and the cache_handle is closed.
		*/
		/* XXX Don't think we need to pass in request_rec or types ... */
		int cache_remove_entity(request_rec r, const char types, cache_handle_t *h)
		{
		h->remove_entity(h);
		return 1;
		}

		/*
		* select a specific URL entity in the cache
		*
		@@ -122,10 +109,9 @@ int cache_remove_entity(request_rec r, const char types, cache_handle_t *h)
		* This function returns OK if successful, DECLINED if no
		* cached entity fits the bill.
		*/
		int cache_select_url(request_rec r, const char types, char *url)
		int cache_select_url(request_rec r, char url)
		{
		const char *next = types;
		const char *type;
		cache_provider_list *list;
		apr_status_t rv;
		cache_handle_t *h;
		char *key;
		@@ -139,17 +125,20 @@ int cache_select_url(request_rec r, const char types, char *url)
		/* go through the cache types till we get a match */
		h = cache->handle = apr_palloc(r->pool, sizeof(cache_handle_t));

		while (next) {
		type = ap_cache_tokstr(r->pool, next, &next);
		switch ((rv = cache_run_open_entity(h, r, type, key))) {
		list = cache->providers;

		while (list) {
		switch ((rv = list->provider->open_entity(h, r, key))) {
		case OK: {
		char *vary = NULL;
		const char *varyhdr = NULL;
		if (cache_read_entity_headers(h, r) != APR_SUCCESS) {
		if (list->provider->recall_headers(h, r) != APR_SUCCESS) {
		/* TODO: Handle this error */
		return DECLINED;
		}

		r->filename = apr_pstrdup(r->pool, h->cache_obj->info.filename);

		/*
		* Check Content-Negotiation - Vary
		*
		@@ -205,10 +194,13 @@ int cache_select_url(request_rec r, const char types, char *url)
		return DECLINED;
		}
		}
		cache->provider = list->provider;
		cache->provider_name = list->provider_name;
		return OK;
		}
		case DECLINED: {
		/* try again with next cache type */
		list = list->next;
		continue;
		}
		default: {
		@@ -222,37 +214,6 @@ int cache_select_url(request_rec r, const char types, char *url)
		return DECLINED;
		}

		apr_status_t cache_write_entity_headers(cache_handle_t *h,
		request_rec *r,
		cache_info *info)
		{
		return (h->write_headers(h, r, info));
		}
		apr_status_t cache_write_entity_body(cache_handle_t h, request_rec r, apr_bucket_brigade *b)
		{
		return (h->write_body(h, r, b));
		}

		apr_status_t cache_read_entity_headers(cache_handle_t h, request_rec r)
		{
		apr_status_t rv;
		cache_info *info = &(h->cache_obj->info);

		/* Build the header table from info in the info struct */
		rv = h->read_headers(h, r);
		if (rv != APR_SUCCESS) {
		return rv;
		}

		r->filename = apr_pstrdup(r->pool, info->filename );

		return APR_SUCCESS;
		}
		apr_status_t cache_read_entity_body(cache_handle_t h, apr_pool_t p, apr_bucket_brigade *b)
		{
		return (h->read_body(h, p, b));
		}

		apr_status_t cache_generate_key_default( request_rec r, apr_pool_tp, char**key )
		{
		if (r->hostname) {
		@@ -263,17 +224,3 @@ apr_status_t cache_generate_key_default( request_rec r, apr_pool_tp, char**key
		}
		return APR_SUCCESS;
		}

		APR_IMPLEMENT_EXTERNAL_HOOK_RUN_FIRST(cache, CACHE, int, create_entity,
		(cache_handle_t h, request_rec r, const char *type,
		const char *urlkey, apr_off_t len),
		(h, r, type,urlkey,len),DECLINED)
		APR_IMPLEMENT_EXTERNAL_HOOK_RUN_FIRST(cache, CACHE, int, open_entity,
		(cache_handle_t h, request_rec r, const char *type,
		const char *urlkey),(h,r,type,urlkey),
		DECLINED)
		APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(cache, CACHE, int, remove_url,
		(const char type, const char urlkey),
		(type,urlkey),OK,DECLINED)

modules/experimental/cache_util.c

+74 −55

Changes for modules/experimental/cache_util.c: 74 added lines, 55 removed lines.
Original line number	Diff line number	Diff line
		@@ -17,7 +17,7 @@

		#include "mod_cache.h"


		#include <ap_provider.h>

		/* -------------------------------------------------------------- */

		@@ -28,76 +28,76 @@ CACHE_DECLARE(int) ap_cache_request_is_conditional(request_rec *r)
		apr_table_get(r->headers_in, "If-None-Match") \|\|
		apr_table_get(r->headers_in, "If-Modified-Since") \|\|
		apr_table_get(r->headers_in, "If-Unmodified-Since")) {

		return 1;
		}
		return 0;
		}


		/* remove other filters from filter stack */
		CACHE_DECLARE(void) ap_cache_reset_output_filters(request_rec *r)
		{
		ap_filter_t *f = r->output_filters;

		while (f) {
		if (!strcasecmp(f->frec->name, "CORE") \|\|
		!strcasecmp(f->frec->name, "CONTENT_LENGTH") \|\|
		!strcasecmp(f->frec->name, "HTTP_HEADER")) {
		f = f->next;
		continue;
		}
		else {
		ap_remove_output_filter(f);
		f = f->next;
		}
		}
		}

		CACHE_DECLARE(const char )ap_cache_get_cachetype(request_rec r,
		CACHE_DECLARE(cache_provider_list )ap_cache_get_providers(request_rec r,
		cache_server_conf *conf,
		const char *url)
		{
		const char *type = NULL;
		cache_provider_list *providers = NULL;
		int i;

		/* we can't cache if there's no URL */
		/* Is this case even possible?? */
		if (!url) return NULL;

		/* loop through all the cacheenable entries */
		for (i = 0; i < conf->cacheenable->nelts; i++) {
		struct cache_enable *ent =
		(struct cache_enable *)conf->cacheenable->elts;
		const char *thisurl = ent[i].url;
		const char *thistype = ent[i].type;
		if ((thisurl) && !strncasecmp(thisurl, url, strlen(thisurl))) {
		if (!type) {
		type = thistype;
		if ((ent[i].url) && !strncasecmp(url, ent[i].url, ent[i].urllen)) {
		/* Fetch from global config and add to the list. */
		cache_provider *provider;
		provider = ap_lookup_provider(CACHE_PROVIDER_GROUP, ent[i].type,
		"0");
		if (!provider) {
		/* Log an error! */
		}
		else {
		type = apr_pstrcat(r->pool, type, ",", thistype, NULL);
		cache_provider_list *newp;
		newp = apr_pcalloc(r->pool, sizeof(cache_provider_list));
		newp->provider_name = ent[i].type;
		newp->provider = provider;

		if (!providers) {
		providers = newp;
		}
		else {
		cache_provider_list *last = providers;

		while (last->next) {
		last = last->next;
		}
		last->next = newp;
		}
		}
		}
		}

		/* then loop through all the cachedisable entries */
		/* Looking for urls that contain the full cachedisable url and possibly more. */
		/* This means we are disabling cachedisable url and below... */
		/* then loop through all the cachedisable entries
		* Looking for urls that contain the full cachedisable url and possibly
		* more.
		* This means we are disabling cachedisable url and below...
		*/
		for (i = 0; i < conf->cachedisable->nelts; i++) {
		struct cache_disable *ent =
		(struct cache_disable *)conf->cachedisable->elts;
		const char *thisurl = ent[i].url;
		if ((thisurl) && !strncasecmp(thisurl, url, strlen(thisurl))) {
		type = NULL;
		if ((ent[i].url) && !strncasecmp(url, ent[i].url, ent[i].urllen)) {
		/* Stop searching now. */
		return NULL;
		}
		}

		return type;
		return providers;
		}


		/* do a HTTP/1.1 age calculation */
		CACHE_DECLARE(apr_int64_t) ap_cache_current_age(cache_info *info, const apr_time_t age_value,
		CACHE_DECLARE(apr_int64_t) ap_cache_current_age(cache_info *info,
		const apr_time_t age_value,
		apr_time_t now)
		{
		apr_time_t apparent_age, corrected_received_age, response_delay,
		@@ -121,7 +121,8 @@ CACHE_DECLARE(apr_int64_t) ap_cache_current_age(cache_info *info, const apr_time
		CACHE_DECLARE(int) ap_cache_check_freshness(cache_request_rec *cache,
		request_rec *r)
		{
		apr_int64_t age, maxage_req, maxage_cresp, maxage, smaxage, maxstale, minfresh;
		apr_int64_t age, maxage_req, maxage_cresp, maxage, smaxage, maxstale;
		apr_int64_t minfresh;
		int age_in_errhdr = 0;
		const char cc_cresp, cc_ceresp, *cc_req;
		const char *agestr = NULL;
		@@ -134,7 +135,7 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_request_rec *cache,
		* We now want to check if our cached data is still fresh. This depends
		* on a few things, in this order:
		*
		* - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache no-cache in
		* - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache. no-cache in
		* either the request or the cached response means that we must
		* revalidate the request unconditionally, overriding any expiration
		* mechanism. It's equivalent to max-age=0,must-revalidate.
		@@ -182,50 +183,64 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_request_rec *cache,
		age = ap_cache_current_age(info, age_c, r->request_time);

		/* extract s-maxage */
		if (cc_cresp && ap_cache_liststr(r->pool, cc_cresp, "s-maxage", &val))
		if (cc_cresp && ap_cache_liststr(r->pool, cc_cresp, "s-maxage", &val)) {
		smaxage = apr_atoi64(val);
		}
		else if (cc_ceresp && ap_cache_liststr(r->pool, cc_ceresp, "s-maxage", &val)) {
		smaxage = apr_atoi64(val);
		}
		else
		else {
		smaxage = -1;
		}

		/* extract max-age from request */
		if (cc_req && ap_cache_liststr(r->pool, cc_req, "max-age", &val))
		if (cc_req && ap_cache_liststr(r->pool, cc_req, "max-age", &val)) {
		maxage_req = apr_atoi64(val);
		else
		}
		else {
		maxage_req = -1;
		}

		/* extract max-age from response */
		if (cc_cresp && ap_cache_liststr(r->pool, cc_cresp, "max-age", &val))
		if (cc_cresp && ap_cache_liststr(r->pool, cc_cresp, "max-age", &val)) {
		maxage_cresp = apr_atoi64(val);
		}
		else if (cc_ceresp && ap_cache_liststr(r->pool, cc_ceresp, "max-age", &val)) {
		maxage_cresp = apr_atoi64(val);
		}
		else
		{
		maxage_cresp = -1;
		}

		/*
		* if both maxage request and response, the smaller one takes priority
		*/
		if (-1 == maxage_req)
		if (-1 == maxage_req) {
		maxage = maxage_cresp;
		else if (-1 == maxage_cresp)
		}
		else if (-1 == maxage_cresp) {
		maxage = maxage_req;
		else
		}
		else {
		maxage = MIN(maxage_req, maxage_cresp);
		}

		/* extract max-stale */
		if (cc_req && ap_cache_liststr(r->pool, cc_req, "max-stale", &val))
		if (cc_req && ap_cache_liststr(r->pool, cc_req, "max-stale", &val)) {
		maxstale = apr_atoi64(val);
		else
		}
		else {
		maxstale = 0;
		}

		/* extract min-fresh */
		if (cc_req && ap_cache_liststr(r->pool, cc_req, "min-fresh", &val))
		if (cc_req && ap_cache_liststr(r->pool, cc_req, "min-fresh", &val)) {
		minfresh = apr_atoi64(val);
		else
		}
		else {
		minfresh = 0;
		}

		/* override maxstale if must-revalidate or proxy-revalidate */
		if (maxstale && ((cc_cresp &&
		@@ -275,7 +290,8 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_request_rec *cache,
		/* add warning if maxstale overrode freshness calculation */
		if (!(((smaxage != -1) && age < smaxage) \|\|
		((maxage != -1) && age < maxage) \|\|
		(info->expire != APR_DATE_BAD && (info->expire - info->date) > age))) {
		(info->expire != APR_DATE_BAD &&
		(info->expire - info->date) > age))) {
		/* make sure we don't stomp on a previous warning */
		if ((warn_head == NULL) \|\|
		((warn_head != NULL) && (ap_strstr_c(warn_head, "110") == NULL))) {
		@@ -303,6 +319,7 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_request_rec *cache,
		}
		return 0; /* Cache object is stale */
		}

		/*
		* list is a comma-separated list of case-insensitive tokens, with
		* optional whitespace around the tokens.
		@@ -380,7 +397,8 @@ CACHE_DECLARE(int) ap_cache_liststr(apr_pool_t p, const char list,
		}

		/* return each comma separated token, one at a time */
		CACHE_DECLARE(const char )ap_cache_tokstr(apr_pool_t p, const char list, const char *str)
		CACHE_DECLARE(const char )ap_cache_tokstr(apr_pool_t p, const char *list,
		const char **str)
		{
		apr_size_t i;
		const char *s;
		@@ -487,7 +505,8 @@ static void cache_hash(const char it, char val, int ndepth, int nlength)
		val[i + 22 - k] = '\0';
		}

		CACHE_DECLARE(char )generate_name(apr_pool_t p, int dirlevels, int dirlength, const char *name)
		CACHE_DECLARE(char )generate_name(apr_pool_t p, int dirlevels,
		int dirlength, const char *name)
		{
		char hashfile[66];
		cache_hash(name, hashfile, dirlevels, dirlength);

modules/experimental/mod_cache.c

+134 −182

File changed.

Preview size limit exceeded, changes collapsed.

modules/experimental/mod_cache.h

+41 −39

Changes for modules/experimental/mod_cache.h: 41 added lines, 39 removed lines.
Original line number	Diff line number	Diff line
		@@ -64,11 +64,7 @@
		#include <arpa/inet.h>
		#endif

		/* USE_ATOMICS should be replaced with the appropriate APR feature macro */
		#define USE_ATOMICS
		#ifdef USE_ATOMICS
		#include "apr_atomic.h"
		#endif

		#ifndef MAX
		#define MAX(a,b) ((a) > (b) ? (a) : (b))
		@@ -79,7 +75,6 @@

		/* default completion is 60% */
		#define DEFAULT_CACHE_COMPLETION (60)
		#define MAX_URL_LENGTH 1024
		#define MSEC_ONE_DAY ((apr_time_t)(86400APR_USEC_PER_SEC)) / one day, in microseconds */
		#define MSEC_ONE_HR ((apr_time_t)(3600APR_USEC_PER_SEC)) / one hour, in microseconds */
		#define MSEC_ONE_MIN ((apr_time_t)(60APR_USEC_PER_SEC)) / one minute, in microseconds */
		@@ -112,10 +107,12 @@
		struct cache_enable {
		const char *url;
		const char *type;
		apr_size_t urllen;
		};

		struct cache_disable {
		const char *url;
		apr_size_t urllen;
		};

		/* static information about the local cache */
		@@ -175,29 +172,46 @@ struct cache_object {
		void vobj; / Opaque portion (specific to the cache implementation) of the cache object */
		apr_size_t count; /* Number of body bytes written to the cache so far */
		int complete;
		#ifdef USE_ATOMICS
		apr_atomic_t refcount;
		#else
		apr_size_t refcount;
		#endif
		apr_uint32_t refcount;
		apr_size_t cleanup;
		};

		typedef struct cache_handle cache_handle_t;

		#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 b);
		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);
		int (open_entity) (cache_handle_t h, request_rec *r,
		const char *urlkey);
		int (remove_url) (const char urlkey);
		} cache_provider;

		/* 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;
		};

		struct cache_handle {
		cache_object_t *cache_obj;
		int (remove_entity) (cache_handle_t h);
		apr_status_t (write_headers)(cache_handle_t h, request_rec r, cache_info i);
		apr_status_t (write_body)(cache_handle_t h, request_rec r, apr_bucket_brigade b);
		apr_status_t (read_headers) (cache_handle_t h, request_rec *r);
		apr_status_t (read_body) (cache_handle_t h, apr_pool_t p, apr_bucket_brigade bb);
		apr_table_t req_hdrs; / These are the original request headers */
		};

		/* per request cache information */
		typedef struct {
		const char types; / the types of caches allowed */
		const char type; / the type of cache selected */
		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 entitey fresh? */
		cache_handle_t handle; / current cache handle */
		int in_checked; /* CACHE_IN must cache the entity */
		@@ -227,8 +241,7 @@ CACHE_DECLARE(char ) generate_name(apr_pool_t p, int dirlevels,
		int dirlength,
		const char *name);
		CACHE_DECLARE(int) ap_cache_request_is_conditional(request_rec *r);
		CACHE_DECLARE(void) ap_cache_reset_output_filters(request_rec *r);
		CACHE_DECLARE(const char )ap_cache_get_cachetype(request_rec r, cache_server_conf conf, const char url);
		CACHE_DECLARE(cache_provider_list )ap_cache_get_providers(request_rec r, cache_server_conf conf, const char url);
		CACHE_DECLARE(int) ap_cache_liststr(apr_pool_t p, const char list,
		const char key, char *val);
		CACHE_DECLARE(const char )ap_cache_tokstr(apr_pool_t p, const char list, const char *str);
		@@ -241,10 +254,9 @@ CACHE_DECLARE(apr_table_t )ap_cache_cacheable_hdrs_out(apr_pool_t pool, apr_ta
		/**
		* cache_storage.c
		*/
		int cache_remove_url(request_rec r, const char types, char *url);
		int cache_create_entity(request_rec r, const char types, char *url, apr_off_t size);
		int cache_remove_entity(request_rec r, const char types, cache_handle_t *h);
		int cache_select_url(request_rec r, const char types, char *url);
		int cache_remove_url(request_rec r, char url);
		int cache_create_entity(request_rec r, char url, apr_off_t size);
		int cache_select_url(request_rec r, char url);
		apr_status_t cache_generate_key_default( request_rec r, apr_pool_tp, char**key );
		/**
		* create a key for the cache based on the request record
		@@ -252,12 +264,13 @@ apr_status_t cache_generate_key_default( request_rec r, apr_pool_tp, char**key
		*/
		const char* cache_create_key( request_rec*r );

		apr_status_t cache_write_entity_headers(cache_handle_t h, request_rec r, cache_info *info);
		apr_status_t cache_write_entity_body(cache_handle_t h, request_rec r, apr_bucket_brigade *bb);

		apr_status_t cache_read_entity_headers(cache_handle_t h, request_rec r);
		apr_status_t cache_read_entity_body(cache_handle_t h, apr_pool_t p, apr_bucket_brigade *bb);
		/*
		apr_status_t cache_store_entity_headers(cache_handle_t h, request_rec r, cache_info *info);
		apr_status_t cache_store_entity_body(cache_handle_t h, request_rec r, apr_bucket_brigade *bb);

		apr_status_t cache_recall_entity_headers(cache_handle_t h, request_rec r);
		apr_status_t cache_recall_entity_body(cache_handle_t h, apr_pool_t p, apr_bucket_brigade *bb);
		*/

		/* hooks */

		@@ -282,17 +295,6 @@ apr_status_t cache_read_entity_body(cache_handle_t h, apr_pool_t p, apr_bucket
		#define CACHE_DECLARE_DATA __declspec(dllimport)
		#endif

		APR_DECLARE_EXTERNAL_HOOK(cache, CACHE, int, create_entity,
		(cache_handle_t h, request_rec r, const char *type,
		const char *urlkey, apr_off_t len))
		APR_DECLARE_EXTERNAL_HOOK(cache, CACHE, int, open_entity,
		(cache_handle_t h, request_rec r, const char *type,
		const char *urlkey))
		APR_DECLARE_EXTERNAL_HOOK(cache, CACHE, int, remove_url,
		(const char type, const char urlkey))



		APR_DECLARE_OPTIONAL_FN(apr_status_t,
		ap_cache_generate_key,
		(request_rec r, apr_pool_tp, char**key ));