[tracker-miners/wip/carlosg/dbus-api-changes: 3/5] libtracker-miner: Add API to prioritize graphs

[Carlos Garnacho <carlosg src gnome org>]

commit 8676584012fb9f9abbaf4d643c045f8080ba6182
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Jun 20 21:44:39 2020 +0200

    libtracker-miner: Add API to prioritize graphs
    
    This replaces the API to prioritize classes. These graphs are simply
    queried first in the UNION.

 src/libtracker-miner/tracker-decorator.c | 60 +++++++++++++++++++++++++-------
 src/libtracker-miner/tracker-decorator.h |  3 ++
 2 files changed, 51 insertions(+), 12 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-decorator.c b/src/libtracker-miner/tracker-decorator.c
index bcaa31376..9573f526a 100644
--- a/src/libtracker-miner/tracker-decorator.c
+++ b/src/libtracker-miner/tracker-decorator.c
@@ -71,6 +71,8 @@ struct _TrackerDecoratorPrivate {
 
        GQueue item_cache; /* Queue of TrackerDecoratorInfo */
 
+       GStrv priority_graphs;
+
        /* Arrays of tracker IDs */
        GArray *prepended_ids;
        GSequence *blacklist_items;
@@ -573,10 +575,13 @@ decorator_cancel_active_tasks (TrackerDecorator *decorator)
        g_hash_table_remove_all (priv->tasks);
 }
 
-static gchar *
-create_query_string (TrackerDecorator  *decorator,
-                     gchar            **select_clauses)
+static gboolean
+append_graph_patterns (TrackerDecorator *decorator,
+                       GString          *query,
+                       gboolean          priority,
+                       gboolean          first)
 {
+       TrackerDecoratorPrivate *priv = decorator->priv;
        const gchar *graphs[] = {
                "tracker:Audio",
                "tracker:Pictures",
@@ -584,7 +589,32 @@ create_query_string (TrackerDecorator  *decorator,
                "tracker:Software",
                "tracker:Documents",
        };
+       gint i;
+
+       for (i = 0; i < G_N_ELEMENTS (graphs); i++) {
+               if (priority !=
+                   (priv->priority_graphs &&
+                    g_strv_contains ((const gchar * const *) priv->priority_graphs, graphs[i])))
+                       continue;
+
+               if (!first)
+                       g_string_append (query, "UNION ");
+
+               g_string_append_printf (query,
+                                       "{ GRAPH %s { ?urn a nfo:FileDataObject } } ",
+                                       graphs[i]);
+               first = FALSE;
+       }
+
+       return first;
+}
+
+static gchar *
+create_query_string (TrackerDecorator  *decorator,
+                     gchar            **select_clauses)
+{
        GString *query;
+       gboolean first;
        gint i;
 
        query = g_string_new ("SELECT ");
@@ -595,15 +625,9 @@ create_query_string (TrackerDecorator  *decorator,
 
        g_string_append (query, "{ ");
 
-       for (i = 0; i < G_N_ELEMENTS (graphs); i++) {
-               if (i > 0) {
-                       g_string_append (query, "UNION ");
-               }
-
-               g_string_append_printf (query,
-                                       "{ GRAPH %s { ?urn a nfo:FileDataObject } } ",
-                                       graphs[i]);
-       }
+       /* Add priority graphs first, so they come up first in the query */
+       first = append_graph_patterns (decorator, query, TRUE, TRUE);
+       append_graph_patterns (decorator, query, FALSE, first);
 
        g_string_append_printf (query,
                                "FILTER (NOT EXISTS {"
@@ -957,6 +981,7 @@ tracker_decorator_finalize (GObject *object)
 
        g_clear_object (&priv->remaining_items_query);
        g_clear_object (&priv->item_count_query);
+       g_strfreev (priv->priority_graphs);
 
        g_cancellable_cancel (priv->cancellable);
        g_clear_object (&priv->cancellable);
@@ -1291,6 +1316,17 @@ tracker_decorator_next_finish (TrackerDecorator  *decorator,
        return g_task_propagate_pointer (G_TASK (result), error);
 }
 
+void
+tracker_decorator_set_priority_graphs (TrackerDecorator    *decorator,
+                                       const gchar * const *graphs)
+{
+       TrackerDecoratorPrivate *priv = decorator->priv;
+
+       g_strfreev (priv->priority_graphs);
+       priv->priority_graphs = g_strdupv ((gchar **) graphs);
+       decorator_rebuild_cache (decorator);
+}
+
 /**
  * tracker_decorator_info_get_urn:
  * @info: a #TrackerDecoratorInfo.
diff --git a/src/libtracker-miner/tracker-decorator.h b/src/libtracker-miner/tracker-decorator.h
index c497fe906..afee17e33 100644
--- a/src/libtracker-miner/tracker-decorator.h
+++ b/src/libtracker-miner/tracker-decorator.h
@@ -115,6 +115,9 @@ TrackerDecoratorInfo *
                                                    GAsyncResult         *result,
                                                    GError              **error);
 
+void          tracker_decorator_set_priority_graphs (TrackerDecorator    *decorator,
+                                                     const gchar * const *graphs);
+
 GType         tracker_decorator_info_get_type     (void) G_GNUC_CONST;
 
 TrackerDecoratorInfo *