[tracker/wip/carlosg/wal-and-other-fixes: 1/8] libtracker-sparql: Handle notifier query cursor in a thread

[Carlos Garnacho <carlosg src gnome org>]

commit b418cb17e1982dfd9be88d0543fd02e69af68583
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Jun 27 18:37:30 2020 +0200

    libtracker-sparql: Handle notifier query cursor in a thread
    
    Take this out of the main thread, so we don't block it when dealing
    with large sets of changes.

 src/libtracker-sparql/tracker-notifier.c | 86 +++++++++++++++++++++++---------
 1 file changed, 63 insertions(+), 23 deletions(-)
---
diff --git a/src/libtracker-sparql/tracker-notifier.c b/src/libtracker-sparql/tracker-notifier.c
index 4f607f056..21101f9b1 100644
--- a/src/libtracker-sparql/tracker-notifier.c
+++ b/src/libtracker-sparql/tracker-notifier.c
@@ -472,33 +472,17 @@ ensure_extra_info_statement (TrackerNotifier           *notifier,
 }
 
 static void
-query_extra_info_cb (GObject      *object,
-                     GAsyncResult *res,
-                     gpointer      user_data)
+handle_cursor (GTask        *task,
+              gpointer      source_object,
+              gpointer      task_data,
+              GCancellable *cancellable)
 {
-       TrackerNotifierEventCache *cache = user_data;
-       TrackerSparqlStatement *statement;
-       TrackerSparqlCursor *cursor;
+       TrackerNotifierEventCache *cache = task_data;
+       TrackerSparqlCursor *cursor = source_object;
        TrackerNotifierEvent *event;
        GSequenceIter *iter;
-       GError *error = NULL;
        gint64 id;
 
-       statement = TRACKER_SPARQL_STATEMENT (object);
-       cursor = tracker_sparql_statement_execute_finish (statement, res, &error);
-
-       if (!cursor) {
-               if (!g_error_matches (error,
-                                     G_IO_ERROR,
-                                     G_IO_ERROR_CANCELLED)) {
-                       g_critical ("Could not get cursor: %s\n", error->message);
-               }
-
-               _tracker_notifier_event_cache_free (cache);
-               g_clear_error (&error);
-               return;
-       }
-
        iter = g_sequence_get_begin_iter (cache->sequence);
 
        /* We rely here in both the GPtrArray and the query items being
@@ -523,9 +507,65 @@ query_extra_info_cb (GObject      *object,
                event->urn = g_strdup (tracker_sparql_cursor_get_string (cursor, 1, NULL));
        }
 
-       g_object_unref (cursor);
+       tracker_sparql_cursor_close (cursor);
 
        tracker_notifier_emit_events_in_idle (cache);
+
+       g_task_return_boolean (task, TRUE);
+}
+
+static void
+finish_query (GObject      *source_object,
+              GAsyncResult *res,
+              gpointer      user_data)
+{
+       TrackerSparqlCursor *cursor = TRACKER_SPARQL_CURSOR (source_object);
+       GError *error = NULL;
+
+       if (!g_task_propagate_boolean (G_TASK (res), &error)) {
+               if (!g_error_matches (error,
+                                     G_IO_ERROR,
+                                     G_IO_ERROR_CANCELLED)) {
+                       g_critical ("Error querying notified data: %s\n", error->message);
+               }
+       }
+
+       g_object_unref (cursor);
+       g_clear_error (&error);
+}
+
+static void
+query_extra_info_cb (GObject      *object,
+                     GAsyncResult *res,
+                     gpointer      user_data)
+{
+       TrackerNotifierEventCache *cache = user_data;
+       TrackerSparqlStatement *statement;
+       TrackerNotifierPrivate *priv;
+       TrackerSparqlCursor *cursor;
+       GError *error = NULL;
+       GTask *task;
+
+       statement = TRACKER_SPARQL_STATEMENT (object);
+       cursor = tracker_sparql_statement_execute_finish (statement, res, &error);
+       priv = tracker_notifier_get_instance_private (cache->notifier);
+
+       if (!cursor) {
+               if (!g_error_matches (error,
+                                     G_IO_ERROR,
+                                     G_IO_ERROR_CANCELLED)) {
+                       g_critical ("Could not get cursor: %s\n", error->message);
+               }
+
+               _tracker_notifier_event_cache_free (cache);
+               g_clear_error (&error);
+               return;
+       }
+
+       task = g_task_new (cursor, priv->cancellable, finish_query, NULL);
+       g_task_set_task_data (task, cache, NULL);
+       g_task_run_in_thread (task, handle_cursor);
+       g_object_unref (task);
 }
 
 static void