[tracker] libtracker-direct: Honor tracker_sparql_connection_local_new() API docs

[Carlos Garnacho <carlosg src gnome org>]

commit 982fe134c74f44b652854c30eb2a78fab6ca5db0
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Oct 3 00:58:02 2018 +0200

    libtracker-direct: Honor tracker_sparql_connection_local_new() API docs
    
    At some point we started warning on NULL journal/ontology arguments,
    even though those are documented as having sensible defaults if NULL
    is provided.

 src/libtracker-direct/tracker-direct.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-direct/tracker-direct.c b/src/libtracker-direct/tracker-direct.c
index 9864e7d01..674b8b7a5 100644
--- a/src/libtracker-direct/tracker-direct.c
+++ b/src/libtracker-direct/tracker-direct.c
@@ -245,6 +245,18 @@ tracker_direct_connection_initable_init (GInitable     *initable,
        if (priv->flags & TRACKER_SPARQL_CONNECTION_FLAGS_READONLY)
                db_flags |= TRACKER_DB_MANAGER_READONLY;
 
+       if (!priv->journal)
+               priv->journal = g_object_ref (priv->store);
+
+       if (!priv->ontology) {
+               gchar *filename;
+
+               filename = g_build_filename (SHAREDIR, "tracker", "ontologies",
+                                            "nepomuk", NULL);
+               priv->ontology = g_file_new_for_path (filename);
+               g_free (filename);
+       }
+
        priv->data_manager = tracker_data_manager_new (db_flags | default_flags, priv->store,
                                                       priv->journal, priv->ontology,
                                                       FALSE, FALSE, 100, 100);
@@ -784,8 +796,8 @@ tracker_direct_connection_new (TrackerSparqlConnectionFlags   flags,
                                GError                       **error)
 {
        g_return_val_if_fail (G_IS_FILE (store), NULL);
-       g_return_val_if_fail (G_IS_FILE (journal), NULL);
-       g_return_val_if_fail (G_IS_FILE (ontology), NULL);
+       g_return_val_if_fail (!journal || G_IS_FILE (journal), NULL);
+       g_return_val_if_fail (!ontology || G_IS_FILE (ontology), NULL);
        g_return_val_if_fail (!error || !*error, NULL);
 
        return g_object_new (TRACKER_TYPE_DIRECT_CONNECTION,