discoverer: fix potential tag list leaks

Not that I have ever seen these in practice, but if they
can't happen we may just as well just assign the new tag
list. Merge properly to be on the safe side, and also
avoid a useless tag list copy in the normal case where
there is no tag list yet.

1 files changed, 25 insertions, 15 deletions

diff --git a/gst-libs/gst/pbutils/gstdiscoverer.c b/gst-libs/gst/pbutils/gstdiscoverer.c
index a7c49681b..6291cd7c9 100644
--- a/gst-libs/gst/pbutils/gstdiscoverer.c
+++ b/gst-libs/gst/pbutils/gstdiscoverer.c
@@ -607,6 +607,23 @@ collect_stream_information (GstDiscoverer * dc, PrivateStream * ps, guint idx)
   return st;
 }
 
+/* takes ownership of new_tags, may replace *taglist with a new one */
+static void
+gst_discoverer_merge_and_replace_tags (GstTagList ** taglist,
+    GstTagList * new_tags)
+{
+  if (new_tags == NULL)
+    return;
+
+  if (*taglist == NULL) {
+    *taglist = new_tags;
+    return;
+  }
+
+  gst_tag_list_insert (*taglist, new_tags, GST_TAG_MERGE_REPLACE);
+  gst_tag_list_free (new_tags);
+}
+
 /* Parses a set of caps and tags in st and populates a GstDiscovererStreamInfo
  * structure (parent, if !NULL, otherwise it allocates one)
  */
@@ -664,10 +681,8 @@ collect_information (GstDiscoverer * dc, const GstStructure * st,
         info->max_bitrate = utmp;
 
       /* FIXME: Is it worth it to remove the tags we've parsed? */
-      info->parent.tags = gst_tag_list_merge (info->parent.tags,
-          (GstTagList *) tags_st, GST_TAG_MERGE_REPLACE);
-
-      gst_structure_free (tags_st);
+      gst_discoverer_merge_and_replace_tags (&info->parent.tags,
+          (GstTagList *) tags_st);
     }
 
     if (!info->language && ((GstDiscovererStreamInfo *) info)->tags) {
@@ -728,9 +743,8 @@ collect_information (GstDiscoverer * dc, const GstStructure * st,
         info->max_bitrate = utmp;
 
       /* FIXME: Is it worth it to remove the tags we've parsed? */
-      info->parent.tags = gst_tag_list_merge (info->parent.tags,
-          (GstTagList *) tags_st, GST_TAG_MERGE_REPLACE);
-      gst_structure_free (tags_st);
+      gst_discoverer_merge_and_replace_tags (&info->parent.tags,
+          (GstTagList *) tags_st);
     }
 
     return (GstDiscovererStreamInfo *) info;
@@ -757,10 +771,8 @@ collect_information (GstDiscoverer * dc, const GstStructure * st,
         info->language = g_strdup (language);
 
       /* FIXME: Is it worth it to remove the tags we've parsed? */
-      info->parent.tags = gst_tag_list_merge (info->parent.tags,
-          (GstTagList *) tags_st, GST_TAG_MERGE_REPLACE);
-      gst_structure_free (tags_st);
-
+      gst_discoverer_merge_and_replace_tags (&info->parent.tags,
+          (GstTagList *) tags_st);
     }
 
     if (!info->language && ((GstDiscovererStreamInfo *) info)->tags) {
@@ -787,9 +799,8 @@ collect_information (GstDiscoverer * dc, const GstStructure * st,
 
     if (gst_structure_id_get (st, _TAGS_QUARK,
             GST_TYPE_STRUCTURE, &tags_st, NULL)) {
-      info->tags = gst_tag_list_merge (info->tags, (GstTagList *) tags_st,
-          GST_TAG_MERGE_REPLACE);
-      gst_structure_free (tags_st);
+      gst_discoverer_merge_and_replace_tags (&info->tags,
+          (GstTagList *) tags_st);
     }
 
     return info;
@@ -1197,7 +1208,6 @@ handle_current_sync (GstDiscoverer * dc)
       done = handle_message (dc, msg);
       gst_message_unref (msg);
     }
-
   } while (!done && (g_timer_elapsed (timer, NULL) < deadline));
 
   /* return result */