Start remembering *where* we are storing routerdescs. This will make us easier to move from a RAM-mirrors-disk model to a RAM-caches-disk model, and save maybe around 10MB on a directory server.

svn:r6427

src/or/or.h

@@ -755,6 +755,8 @@ typedef struct signed_descriptor_t {
   char signed_descriptor_digest[DIGEST_LEN];
   char identity_digest[DIGEST_LEN];
   time_t published_on;
+  enum { SAVED_NOWHERE=0, SAVED_IN_CACHE, SAVED_IN_JOURNAL } saved_location;
+  off_t saved_offset;
 } signed_descriptor_t;
 
 /** Information about another onion router in the network. */
@@ -2402,7 +2404,8 @@ int router_append_dirobj_signature(char *buf, size_t buf_len,
                                    const char *digest,
                                    crypto_pk_env_t *private_key);
 int router_parse_list_from_string(const char **s,
-                                  smartlist_t *dest);
+                                  smartlist_t *dest,
+                                  int from_cache);
 int router_parse_routerlist_from_directory(const char *s,
                                            routerlist_t **dest,
                                            crypto_pk_env_t *pkey,

src/or/routerlist.c

@@ -186,6 +186,8 @@ router_append_to_journal(signed_descriptor_t *desc)
     tor_free(fname);
     return -1;
   }
+  desc->saved_location = SAVED_IN_JOURNAL;
+  desc->saved_offset = router_journal_len;
 
   tor_free(fname);
   router_journal_len += len;
@@ -243,6 +245,20 @@ router_rebuild_store(int force)
     log_warn(LD_FS, "Error writing router store to disk.");
     goto done;
   }
+  for (i = 0; i < 2; ++i) {
+    smartlist_t *lst = (i == 0) ? routerlist->old_routers :
+                                  routerlist->routers;
+    off_t offset = 0;
+    SMARTLIST_FOREACH(lst, void *, ptr,
+    {
+      signed_descriptor_t *sd = (i==0) ?
+        ((signed_descriptor_t*)ptr): &((routerinfo_t*)ptr)->cache_info;
+
+      sd->saved_location = SAVED_IN_CACHE;
+      sd->saved_offset = offset;
+      offset += sd->signed_descriptor_len;
+    });
+  }
 
   tor_snprintf(fname, fname_len, "%s/cached-routers.new",
                options->DataDirectory);
@@ -1920,7 +1936,7 @@ router_load_routers_from_string(const char *s, int from_cache,
   char fp[HEX_DIGEST_LEN+1];
   const char *msg;
 
-  router_parse_list_from_string(&s, routers);
+  router_parse_list_from_string(&s, routers, from_cache);
 
   routers_update_status_from_networkstatus(routers, !from_cache);
 

src/or/routerparse.c

@@ -637,15 +637,17 @@ check_directory_signature(const char *digest,
  * are not complete. Returns 0 on success and -1 on failure.
  */
 int
-router_parse_list_from_string(const char **s, smartlist_t *dest)
+router_parse_list_from_string(const char **s, smartlist_t *dest,
+                              int from_cache)
 {
   routerinfo_t *router;
-  const char *end, *cp;
+  const char *end, *cp, *start;
 
   tor_assert(s);
   tor_assert(*s);
   tor_assert(dest);
 
+  start = *s;
   while (1) {
     *s = eat_whitespace(*s);
     /* Don't start parsing the rest of *s unless it contains a router. */
@@ -683,6 +685,10 @@ router_parse_list_from_string(const char **s, smartlist_t *dest)
       log_warn(LD_DIR, "Error reading router; skipping");
       continue;
     }
+    if (from_cache) {
+      router->cache_info.saved_location = SAVED_IN_CACHE;
+      router->cache_info.saved_offset = *s - start;
+    }
     smartlist_add(dest, router);
   }