[tracker] TrackerDecorator: Sort elem_queue to extract important files first

[Xavier Claessens <xclaesse src gnome org>]

commit c6fd84ddb1a1efcb27676deea4ad2d31f39a82c6
Author: Xavier Claessens <xavier claessens collabora co uk>
Date:   Thu Jan 30 18:28:37 2014 -0500

    TrackerDecorator: Sort elem_queue to extract important files first
    
    There are 2 things affecting an element position in the queue:
    prepend (typically files from an USB key the user plugged),
    and prior (the file type matches what applications needs first, e.g.
    nfo:Audio).
    
    The queue is sorted like that:
    1) prepend and prior files
    2) prior files
    3) prepend files
    4) the rest
    
    This garantees that if I open the Music app and plug an USB key, I'll
    get the MP3s from that key first, which is probably want the user
    wants.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=719802
    
    Conflicts:
        src/libtracker-miner/tracker-decorator.c

 src/libtracker-miner/tracker-decorator.c |  100 +++++++++++++++++++++++++-----
 1 files changed, 84 insertions(+), 16 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-decorator.c b/src/libtracker-miner/tracker-decorator.c
index c443f32..f40aa19 100644
--- a/src/libtracker-miner/tracker-decorator.c
+++ b/src/libtracker-miner/tracker-decorator.c
@@ -57,6 +57,7 @@ struct _ElemNode {
        TrackerDecoratorInfo *info;
        gint id;
        gint class_name_id;
+       gboolean prepend;
 };
 
 struct _TrackerDecoratorPrivate {
@@ -71,6 +72,7 @@ struct _TrackerDecoratorPrivate {
        GQueue next_elem_queue;
 
        GArray *class_name_ids;
+       GArray *priority_class_name_ids;
        gint rdf_type_id;
        gint nie_data_source_id;
        gint data_source_id;
@@ -187,6 +189,42 @@ decorator_update_state (TrackerDecorator *decorator,
                g_object_set (decorator, "status", message, NULL);
 }
 
+static gboolean
+class_name_array_contains (GArray *array,
+                           gint    id)
+{
+       guint i;
+
+       for (i = 0; i < array->len; i++) {
+               if (id == g_array_index (array, gint, i))
+                       return TRUE;
+       }
+
+       return FALSE;
+}
+
+static gint
+elem_node_get_priority (TrackerDecorator *decorator,
+                        ElemNode         *node)
+{
+       TrackerDecoratorPrivate *priv;
+       gboolean prior;
+
+       priv = decorator->priv;
+
+       /* We want [prepend and prior, prior, prepend, the rest] */
+       prior = class_name_array_contains (priv->priority_class_name_ids,
+                                          node->class_name_id);
+       if (prior && node->prepend)
+               return G_PRIORITY_HIGH - 1;
+       else if (prior)
+               return G_PRIORITY_HIGH;
+       else if (node->prepend)
+               return G_PRIORITY_HIGH + 1;
+
+       return G_PRIORITY_DEFAULT;
+}
+
 static void
 element_add (TrackerDecorator *decorator,
              gint              id,
@@ -207,14 +245,10 @@ element_add (TrackerDecorator *decorator,
        node = g_new0 (ElemNode, 1);
        node->id = id;
        node->class_name_id = class_name_id;
+       node->prepend = prepend;
 
-       if (prepend) {
-               elem = tracker_priority_queue_add (priv->elem_queue, node,
-                                                  G_PRIORITY_HIGH);
-       } else {
-               elem = tracker_priority_queue_add (priv->elem_queue, node,
-                                                  G_PRIORITY_DEFAULT);
-       }
+       elem = tracker_priority_queue_add (priv->elem_queue, node,
+                                          elem_node_get_priority (decorator, node));
 
        g_hash_table_insert (priv->elems, GINT_TO_POINTER (id), elem);
        priv->stats_n_elems++;
@@ -247,7 +281,7 @@ element_remove_link (TrackerDecorator *decorator,
                return;
        }
 
-       tracker_priority_queue_remove (priv->elem_queue, elem_link);
+       tracker_priority_queue_remove_node (priv->elem_queue, elem_link);
        g_hash_table_remove (priv->elems, GINT_TO_POINTER (node->id));
 
        if (emit && g_hash_table_size (priv->elems) == 0) {
@@ -581,16 +615,10 @@ class_name_id_handled (TrackerDecorator *decorator,
                        gint              id)
 {
        TrackerDecoratorPrivate *priv;
-       guint i;
 
        priv = decorator->priv;
 
-       for (i = 0; i < priv->class_name_ids->len; i++) {
-               if (id == g_array_index (priv->class_name_ids, gint, i))
-                       return TRUE;
-       }
-
-       return FALSE;
+       return class_name_array_contains (priv->class_name_ids, id);
 }
 
 static void
@@ -708,6 +736,7 @@ tracker_decorator_finalize (GObject *object)
 
        g_array_unref (priv->class_name_ids);
        tracker_priority_queue_unref (priv->elem_queue);
+       g_array_unref (priv->priority_class_name_ids);
        g_hash_table_unref (priv->elems);
        g_free (priv->data_source);
        g_strfreev (priv->class_names);
@@ -916,6 +945,7 @@ tracker_decorator_init (TrackerDecorator *decorator)
        priv->elems = g_hash_table_new (NULL, NULL);
        priv->elem_queue = tracker_priority_queue_new ();
        priv->class_name_ids = g_array_new (FALSE, FALSE, sizeof (gint));
+       priv->priority_class_name_ids = g_array_new (FALSE, FALSE, sizeof (gint));
        priv->batch_size = DEFAULT_BATCH_SIZE;
        priv->sparql_buffer = g_ptr_array_new_with_free_func (g_free);
        priv->timer = g_timer_new ();
@@ -1271,9 +1301,47 @@ void
 tracker_decorator_set_priority_rdf_types (TrackerDecorator    *decorator,
                                           const gchar * const *rdf_types)
 {
+       TrackerDecoratorPrivate *priv;
+       TrackerPriorityQueue *new_queue;
+       guint i, j;
+       GList *elem_link;
+
        g_return_if_fail (TRACKER_DECORATOR (decorator));
+       g_return_if_fail (rdf_types != NULL);
+
+       priv = decorator->priv;
 
-       /* FIXME: Not Implemented */
+       if (priv->priority_class_name_ids->len > 0)
+               g_array_remove_range (priv->priority_class_name_ids, 0,
+                                     priv->priority_class_name_ids->len);
+
+       for (i = 0; rdf_types[i] != NULL; i++) {
+               for (j = 0; priv->class_names[j] != NULL; j++) {
+                       gint id;
+
+                       if (!g_str_equal (rdf_types[i], priv->class_names[j]))
+                               continue;
+
+                       /* priv->class_names and priv->class_name_ids are in the
+                        * same order */
+                       id = g_array_index (priv->class_name_ids, gint, j);
+                       g_array_append_val (priv->priority_class_name_ids, id);
+                       break;
+               }
+       }
+
+       /* We have to re-evaluate the priority of each element. We also have to
+        * keep the same elem_link because they are referenced in priv->elems.
+        * So we create a new priority queue and transfer nodes one by one. */
+       new_queue = tracker_priority_queue_new ();
+       while ((elem_link = tracker_priority_queue_pop_node (priv->elem_queue, NULL))) {
+               ElemNode *node = elem_link->data;
+
+               tracker_priority_queue_add_node (new_queue, elem_link,
+                                                elem_node_get_priority (decorator, node));
+       }
+       tracker_priority_queue_unref (priv->elem_queue);
+       priv->elem_queue = new_queue;
 }
 
 /**