[tracker/wip/carlosg/sparql1.1: 34/80] libtracker-data: Ensure triples cursor is entirely reset on filter()

[Carlos Garnacho <carlosg src gnome org>]

commit 6ca812c98f45b66c8fc95aef63779fccfb111139
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Jun 8 15:59:17 2019 +0200

    libtracker-data: Ensure triples cursor is entirely reset on filter()
    
    The cursor may actually be reused multiple times for different values,
    in which case we'd get filter() called again on it. Ensure the cursor
    is properly reset so it can handle later items as if brand new.

 src/libtracker-data/tracker-vtab-triples.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)
---
diff --git a/src/libtracker-data/tracker-vtab-triples.c b/src/libtracker-data/tracker-vtab-triples.c
index fa7b21fde..ee13a805e 100644
--- a/src/libtracker-data/tracker-vtab-triples.c
+++ b/src/libtracker-data/tracker-vtab-triples.c
@@ -98,17 +98,24 @@ tracker_triples_vtab_free (gpointer data)
 }
 
 static void
-tracker_triples_cursor_free (gpointer data)
+tracker_triples_cursor_reset (TrackerTriplesCursor *cursor)
 {
-       TrackerTriplesCursor *cursor = data;
-
-       if (cursor->stmt)
-               sqlite3_finalize (cursor->stmt);
-
+       g_clear_pointer (&cursor->stmt, sqlite3_finalize);
        g_clear_pointer (&cursor->match.graph, sqlite3_value_free);
        g_clear_pointer (&cursor->match.subject, sqlite3_value_free);
        g_clear_pointer (&cursor->match.predicate, sqlite3_value_free);
-       g_list_free (cursor->properties);
+       g_clear_pointer (&cursor->properties, g_list_free);
+       cursor->match.idxFlags = 0;
+       cursor->rowid = 0;
+       cursor->finished = FALSE;
+}
+
+static void
+tracker_triples_cursor_free (gpointer data)
+{
+       TrackerTriplesCursor *cursor = data;
+
+       tracker_triples_cursor_reset (cursor);
        g_free (cursor);
 }
 
@@ -411,6 +418,8 @@ triples_filter (sqlite3_vtab_cursor  *vtab_cursor,
        TrackerTriplesCursor *cursor = (TrackerTriplesCursor *) vtab_cursor;
        int rc;
 
+       tracker_triples_cursor_reset (cursor);
+
        if (idx & IDX_COL_GRAPH) {
                int idx = idx_str[COL_GRAPH];
                cursor->match.graph = sqlite3_value_dup (argv[idx]);