The attached patch changes how we store the contents of a varied URI.
If a URI is varied, all variations will be stored underneath a new
<hash>.header.vary/ directory.
This enables future tools, such as the ability to easily delete a URI
from the cache, without scanning the entire tree, just to find the
possible varied versions.
The code was written pretty quickly, and I would love some feedback both
on the idea, and the hacky way I did it :)
-Paul
Index: modules/cache/mod_disk_cache.c
===================================================================
--- modules/cache/mod_disk_cache.c (revision 219914)
+++ modules/cache/mod_disk_cache.c (working copy)
@@ -50,8 +50,8 @@
* CRLF
*/
-#define VARY_FORMAT_VERSION 1
-#define DISK_FORMAT_VERSION 2
+#define VARY_FORMAT_VERSION 3
+#define DISK_FORMAT_VERSION 4
typedef struct {
/* Indicates the format of the header struct stored on-disk. */
@@ -76,6 +76,7 @@
typedef struct disk_cache_object {
const char *root; /* the location of the cache directory */
char *tempfile; /* temp file tohold the content */
+ const char *prefix;
const char *datafile; /* name of file where the data will go */
const char *hdrsfile; /* name of file where the hdrs will go */
const char *hashfile; /* Computed hash key for this URI */
@@ -124,6 +125,8 @@
*/
#define CACHE_HEADER_SUFFIX ".header"
#define CACHE_DATA_SUFFIX ".data"
+#define CACHE_VDIR_SUFFIX ".vary"
+
static char *header_file(apr_pool_t *p, disk_cache_conf *conf,
disk_cache_object_t *dobj, const char *name)
{
@@ -131,8 +134,15 @@
dobj->hashfile = ap_cache_generate_name(p, conf->dirlevels,
conf->dirlength, name);
}
- return apr_pstrcat(p, conf->cache_root, "/", dobj->hashfile,
- CACHE_HEADER_SUFFIX, NULL);
+
+ if (dobj->prefix) {
+ return apr_pstrcat(p, dobj->prefix, CACHE_VDIR_SUFFIX, "/",
+ dobj->hashfile, CACHE_HEADER_SUFFIX, NULL);
+ }
+ else {
+ return apr_pstrcat(p, conf->cache_root, "/", dobj->hashfile,
+ CACHE_HEADER_SUFFIX, NULL);
+ }
}
static char *data_file(apr_pool_t *p, disk_cache_conf *conf,
@@ -142,8 +152,15 @@
dobj->hashfile = ap_cache_generate_name(p, conf->dirlevels,
conf->dirlength, name);
}
- return apr_pstrcat(p, conf->cache_root, "/", dobj->hashfile,
- CACHE_DATA_SUFFIX, NULL);
+
+ if (dobj->prefix) {
+ return apr_pstrcat(p, dobj->prefix, CACHE_VDIR_SUFFIX, "/",
+ dobj->hashfile, CACHE_DATA_SUFFIX, NULL);
+ }
+ else {
+ return apr_pstrcat(p, conf->cache_root, "/", dobj->hashfile,
+ CACHE_DATA_SUFFIX, NULL);
+ }
}
static void mkdir_structure(disk_cache_conf *conf, const char *file,
apr_pool_t *pool)
@@ -352,6 +369,7 @@
obj->key = apr_pstrdup(r->pool, key);
dobj->name = obj->key;
+ dobj->prefix = NULL;
dobj->datafile = data_file(r->pool, conf, dobj, key);
dobj->hdrsfile = header_file(r->pool, conf, dobj, key);
dobj->tempfile = apr_pstrcat(r->pool, conf->cache_root, AP_TEMPFILE, NULL);
@@ -393,6 +411,8 @@
info = &(obj->info);
/* Open the headers file */
+ dobj->prefix = NULL;
+
dobj->hdrsfile = header_file(r->pool, conf, dobj, key);
flags = APR_READ|APR_BINARY|APR_BUFFERED;
rc = apr_file_open(&dobj->hfd, dobj->hdrsfile, flags, 0, r->pool);
@@ -428,6 +448,7 @@
nkey = regen_key(r->pool, r->headers_in, varray, key);
dobj->hashfile = NULL;
+ dobj->prefix = dobj->hdrsfile;
dobj->hdrsfile = header_file(r->pool, conf, dobj, nkey);
flags = APR_READ|APR_BINARY|APR_BUFFERED;
@@ -784,6 +805,7 @@
dobj->tempfile = apr_pstrcat(r->pool, conf->cache_root,
AP_TEMPFILE, NULL);
tmp = regen_key(r->pool, r->headers_in, varray, dobj->name);
+ dobj->prefix = dobj->hdrsfile;
dobj->hashfile = NULL;
dobj->datafile = data_file(r->pool, conf, dobj, tmp);
dobj->hdrsfile = header_file(r->pool, conf, dobj, tmp);
