[rygel] media-export: Add function to count search result

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 8f97748bed6a91836f947ced4bb9f07dff5321cd
Author: Jens Georg <mail jensge org>
Date:   Sun May 16 13:18:26 2010 +0200

    media-export: Add function to count search result
    
    This speeds up virtual folder creation by factor 30. Noticable speed
    improvements on XBox music browsing

 .../rygel-media-export-media-cache.vala            |   71 ++++++++++++++++++++
 .../rygel-media-export-query-container.vala        |    3 +-
 2 files changed, 72 insertions(+), 2 deletions(-)
---
diff --git a/src/plugins/media-export/rygel-media-export-media-cache.vala b/src/plugins/media-export/rygel-media-export-media-cache.vala
index 5794ca5..de47da6 100644
--- a/src/plugins/media-export/rygel-media-export-media-cache.vala
+++ b/src/plugins/media-export/rygel-media-export-media-cache.vala
@@ -181,6 +181,16 @@ public class Rygel.MediaExport.MediaCache : Object {
                  "o.title ASC " +
     "LIMIT ?,?";
 
+    // The uris are joined in to be able to filter by "ref"
+    private const string GET_OBJECT_COUNT_BY_FILTER_STRING =
+    "SELECT COUNT(o.type_fk) FROM Object o " +
+        "JOIN Closure c ON o.upnp_id = c.descendant AND c.ancestor = ? " +
+        "JOIN meta_data m " +
+            "ON o.upnp_id = m.object_fk " +
+    "WHERE %s " +
+    "LIMIT ?,?";
+
+
     private const string CHILDREN_COUNT_STRING =
     "SELECT COUNT(upnp_id) FROM Object WHERE Object.parent = ?";
 
@@ -373,6 +383,67 @@ public class Rygel.MediaExport.MediaCache : Object {
                                            max_objects);
     }
 
+    public long get_object_count_by_search_expression (
+                                        SearchExpression? expression,
+                                        string            container_id,
+                                        uint              offset,
+                                        uint              max_count)
+                                        throws Error {
+        var args = new GLib.ValueArray (0);
+        var filter = this.search_expression_to_sql (expression, args);
+
+        if (filter == null) {
+            return 0;
+        }
+
+        debug (_("Original search: %s"), expression.to_string ());
+        debug (_("Parsed search expression: %s"), filter);
+
+        for (int i = 0; i < args.n_values; i++) {
+            debug ("Arg %d: %s", i, args.get_nth (i).get_string ());
+        }
+
+        var max_objects = modify_limit (max_count);
+
+        return this.get_object_count_by_filter (filter,
+                                                args,
+                                                container_id,
+                                                offset,
+                                                max_objects);
+    }
+
+    public long get_object_count_by_filter (
+                                        string          filter,
+                                        GLib.ValueArray args,
+                                        string          container_id,
+                                        long            offset,
+                                        long            max_count)
+                                        throws Error {
+        GLib.Value v = container_id;
+        args.prepend (v);
+        v = offset;
+        args.append (v);
+        v = max_count;
+        args.append (v);
+        long count = 0;
+
+        debug ("%s %ld %ld", container_id, offset, max_count);
+        debug ("Parameters to bind: %u", args.n_values);
+
+        Database.RowCallback callback = (statement) => {
+            count = statement.column_int (0);
+
+            return false;
+        };
+
+        this.db.exec (GET_OBJECT_COUNT_BY_FILTER_STRING.printf (filter),
+                      args.values,
+                      callback);
+
+        return count;
+    }
+
+
     public Gee.ArrayList<MediaObject> get_objects_by_filter (
                                         string          filter,
                                         GLib.ValueArray args,
diff --git a/src/plugins/media-export/rygel-media-export-query-container.vala b/src/plugins/media-export/rygel-media-export-query-container.vala
index 3a14a7a..8a776cc 100644
--- a/src/plugins/media-export/rygel-media-export-query-container.vala
+++ b/src/plugins/media-export/rygel-media-export-query-container.vala
@@ -120,12 +120,11 @@ internal class Rygel.MediaExport.QueryContainer : DBContainer {
     private int count_children () {
         try {
             if (this.pattern == "") {
-                var children = this.media_db.get_objects_by_search_expression (
+                return (int) this.media_db.get_object_count_by_search_expression (
                                         this.expression,
                                         "0",
                                         0,
                                         -1);
-                return children.size;
             } else {
                 int retval = 0;
                 var data = this.media_db.get_object_attribute_by_search_expression (