Clean up bridge-stats code.

Only write a bridge-stats string if bridge stats have been
initialized.  This behavior is similar to dirreq-stats, entry-stats,
etc.

Also add a few unit tests for the bridge-stats code.

src/or/geoip.c

@@ -1197,8 +1197,8 @@ static char *bridge_stats_extrainfo = NULL;
 /** Return a newly allocated string holding our bridge usage stats by country
  * in a format suitable for inclusion in an extrainfo document. Return NULL on
  * failure.  */
-static char *
-format_bridge_stats_extrainfo(time_t now)
+char *
+geoip_format_bridge_stats(time_t now)
 {
   char *out = NULL, *data = NULL;
   long duration = now - start_of_bridge_stats_interval;
@@ -1206,6 +1206,8 @@ format_bridge_stats_extrainfo(time_t now)
 
   if (duration < 0)
     return NULL;
+  if (!start_of_bridge_stats_interval)
+    return NULL; /* Not initialized. */
 
   format_iso_time(written, now);
   data = geoip_get_client_history(GEOIP_CLIENT_CONNECT);
@@ -1255,7 +1257,7 @@ geoip_bridge_stats_write(time_t now)
   geoip_remove_old_clients(start_of_bridge_stats_interval);
 
   /* Generate formatted string */
-  val = format_bridge_stats_extrainfo(now);
+  val = geoip_format_bridge_stats(now);
   if (val == NULL)
     goto done;
 

src/or/geoip.h

@@ -53,6 +53,7 @@ void geoip_entry_stats_term(void);
 void geoip_reset_entry_stats(time_t now);
 char *geoip_format_entry_stats(time_t now);
 void geoip_bridge_stats_init(time_t now);
+char *geoip_format_bridge_stats(time_t now);
 time_t geoip_bridge_stats_write(time_t now);
 void geoip_bridge_stats_term(void);
 const char *geoip_get_bridge_stats_extrainfo(time_t);

src/test/test.c

@@ -1483,7 +1483,10 @@ test_geoip(void)
   int i, j;
   time_t now = 1281533250; /* 2010-08-11 13:27:30 UTC */
   char *s = NULL;
-  const char *dirreq_stats_1 =
+  const char *bridge_stats_1 =
+      "bridge-stats-end 2010-08-12 13:27:30 (86400 s)\n"
+      "bridge-ips zz=24,xy=8\n",
+  *dirreq_stats_1 =
       "dirreq-stats-end 2010-08-12 13:27:30 (86400 s)\n"
       "dirreq-v3-ips ab=8\n"
       "dirreq-v2-ips \n"
@@ -1594,6 +1597,24 @@ test_geoip(void)
   test_assert(s);
   test_streq("zz=24,xy=8", s);
 
+  /* Start testing bridge statistics by making sure that we don't output
+   * bridge stats without initializing them. */
+  s = geoip_format_bridge_stats(now + 86400);
+  test_assert(!s);
+
+  /* Initialize stats and generate the bridge-stats history string out of
+   * the connecting clients added above. */
+  geoip_bridge_stats_init(now);
+  s = geoip_format_bridge_stats(now + 86400);
+  test_streq(bridge_stats_1, s);
+  tor_free(s);
+
+  /* Stop collecting bridge stats and make sure we don't write a history
+   * string anymore. */
+  geoip_bridge_stats_term();
+  s = geoip_format_bridge_stats(now + 86400);
+  test_assert(!s);
+
   /* Stop being a bridge and start being a directory mirror that gathers
    * directory request statistics. */
   geoip_bridge_stats_term();