[tracker] TrackerDecorator: Query the type of removed elements

[Xavier Claessens <xclaesse src gnome org>]

commit 16302cc91ea384a6ea5fbaecf1db4faa10429fd9
Author: Xavier Claessens <xavier claessens collabora co uk>
Date:   Wed Feb 19 14:06:52 2014 -0500

    TrackerDecorator: Query the type of removed elements
    
    When "?urn nie:dataSource tracker:extractor-data-source" gets removed
    it means that we have to re-extract that file. It should not happen
    in normal usage, only for testing purpose. In that case we have
    to query its type.

 src/libtracker-miner/tracker-decorator.c |   53 +++++++++++++++++++++++++++--
 1 files changed, 49 insertions(+), 4 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-decorator.c b/src/libtracker-miner/tracker-decorator.c
index f40aa19..0cea3f4 100644
--- a/src/libtracker-miner/tracker-decorator.c
+++ b/src/libtracker-miner/tracker-decorator.c
@@ -587,6 +587,46 @@ tracker_decorator_set_property (GObject      *object,
 }
 
 static void
+query_type_and_add_element (TrackerDecorator *decorator,
+                            gint subject)
+{
+       TrackerSparqlConnection *sparql_conn;
+       TrackerSparqlCursor *cursor;
+       GString *query;
+       GError *error = NULL;
+
+       sparql_conn = tracker_miner_get_connection (TRACKER_MINER (decorator));
+
+       query = g_string_new (NULL);
+       g_string_append_printf (query, "select tracker:id (?type) {"
+                                      "  ?urn a ?type . "
+                                      "  FILTER (tracker:id(?urn) = %d ", subject);
+       _tracker_decorator_query_append_rdf_type_filter (decorator, query);
+       g_string_append (query, ")}");
+
+       cursor = tracker_sparql_connection_query (sparql_conn, query->str,
+                                                 NULL, &error);
+       g_string_free (query, TRUE);
+
+       if (error) {
+               g_critical ("Could not get type ID for '%d': %s\n",
+                           subject, error->message);
+               g_error_free (error);
+               return;
+       }
+
+       if (!tracker_sparql_cursor_next (cursor, NULL, NULL)) {
+               g_critical ("'%d' doesn't have a known type", subject);
+       } else {
+               element_add (decorator, subject,
+                            tracker_sparql_cursor_get_integer (cursor, 0),
+                            FALSE);
+       }
+
+       g_object_unref (cursor);
+}
+
+static void
 handle_deletes (TrackerDecorator *decorator,
                 GVariantIter     *iter)
 {
@@ -602,10 +642,15 @@ handle_deletes (TrackerDecorator *decorator,
                else if (predicate == priv->nie_data_source_id &&
                         object == priv->data_source_id) {
                        /* If only the decorator datasource is removed,
-                        * re-process the file from scratch.
-                        */
-                       /* FIXME: Can we know the class_name_id ? */
-                       element_add (decorator, subject, 0, FALSE);
+                        * re-process the file from scratch if it's not already
+                        * queued. We don't know its class_name_id, so we have
+                        * to query it first. This should be rare enough that
+                        * it doesn't matter to accumulate them to query in
+                        * batches. */
+                       if (!g_hash_table_contains (priv->elems,
+                                                   GINT_TO_POINTER (subject))) {
+                               query_type_and_add_element (decorator, subject);
+                       }
                }
        }
 }