rar: Fix caching problem with RAR index archive

The in-memory RAR archive incorrectly thought that a fileref
to the RAR root was not the same archive as a fileref further down in
the RAR archive. This lead to performance issues when browsing RAR
archives.

src/fileaccess/fa_rar.c

@@ -480,13 +480,17 @@ rar_archive_find(const char *url, const char **rp)
  hts_mutex_lock(&rar_global_mutex);
 
  u = mystrdupa(url);
- while((s = strrchr(u, '/')) != NULL) {
-  *s = 0;
- LIST_FOREACH(ra, &rar_archives, ra_link)
+
+ while(1) {
+ LIST_FOREACH(ra, &rar_archives, ra_link) {
  if(!strcasecmp(ra->ra_url, u))
  break;
+ }
  if(ra != NULL)
  break;
+ if((s = strrchr(u, '/')) == NULL)
+ break;
+ *s = 0;
  }
 
  if(ra == NULL) {