backend_firefox: hide dangling keywords

When a bookmark associated with a keyword is deleted,
there may still be dangling references (e.g., tags) to the
corresponding `moz_places` entry.

By filtering out NULL titles, `bookmark_lookup()` and
`bookmark_list()` now only give keywords associated with
valid bookmarks.

src/backend_firefox.c

@@ -2175,7 +2175,8 @@ bookmark_do_list (
     "SELECT min(`b`.`id`), `k`.`id`, `k`.`keyword`" cols " " \
     "FROM `moz_keywords` `k` " join  \
     "JOIN `moz_bookmarks` `b` ON `k`.`place_id` = `b`.`fk` "  \
-    "WHERE `k`.`id` >= ?2 GROUP BY `k`.`place_id` ORDER BY `k`.`id`"
+    "WHERE `k`.`id` >= ?2 AND `b`.`title` IS NOT NULL "  \
+    "GROUP BY `k`.`place_id` ORDER BY `k`.`id`"
 #define BOOKMARK_LIST_KEYWORD     BOOKMARK_LIST_KEYWORD_(,)
 #define BOOKMARK_LIST_KEYWORD_EX  \
     BOOKMARK_LIST_KEYWORD_(", " BOOKMARK_LIST_EX_COLS_,  \
@@ -2267,7 +2268,8 @@ bookmark_do_lookup (
 #define PLACE_ID_BY_KEYWORD(val)  \
     "SELECT `place_id` FROM `moz_keywords` WHERE `keyword` = " val
 #define BOOKMARK_LOOKUP_PLACE_ID_(val)  \
-    BOOKMARK_LOOKUP_(, "`b`.`fk` = " val " ORDER BY `b`.`id` LIMIT 1")
+    BOOKMARK_LOOKUP_(, "`b`.`fk` = " val " AND `b`.`title` IS NOT NULL "  \
+        "ORDER BY `b`.`id` LIMIT 1")
 #define BOOKMARK_LOOKUP_KEYWORD_(val)  \
     BOOKMARK_LOOKUP_PLACE_ID_("(" PLACE_ID_BY_KEYWORD(val) ")")
 #define BOOKMARK_LOOKUP_KEYWORD  BOOKMARK_LOOKUP_KEYWORD_("?2")

src/fs_ops.c

@@ -1532,25 +1532,25 @@ intfs_opendir (
     fuse_ino_t             ino,
     struct fuse_file_info *fi
 ) {
-    int status = 0;
+    uint64_t bm_id = BOOKMARKS_ROOT_ID;
-
     uint32_t flags = 0;
     switch (id) {
       case INTFS_ID_ROOT:
         fi->cache_readdir = 1;
         fi->keep_cache    = 1;
-        break;
+        return 0;
-
-      case INTFS_ID_BOOKMARKS:
-        status = bm_opendir(BOOKMARKS_ROOT_ID, ino, flags, fi);
-        break;
 
       case INTFS_ID_TAGS:
         flags |= BOOKMARKFS_BOOKMARK_TYPE(TAG);
-        status = bm_opendir(TAGS_ROOT_ID, ino, flags, fi);
+        bm_id = TAGS_ROOT_ID;
+        break;
+
+      case INTFS_ID_KEYWORDS:
+        flags |= BOOKMARKFS_BOOKMARK_TYPE(KEYWORD);
+        bm_id = 0;
         break;
     }
-    return status;
+    return bm_opendir(bm_id, ino, flags, fi);
 }
 
 static int