[rygel] media-export: Add virtual containers

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 9a06a236413429717f5be1ed949ec98e622fe281
Author: Jens Georg <mail jensge org>
Date:   Mon Feb 8 13:06:44 2010 +0100

    media-export: Add virtual containers
    
    The virtual containers are based on meta-data columns (Artist, Album, etc.)
    and are generated on-the-fly from the database

 src/plugins/media-export/Makefile.am               |    1 +
 .../rygel-media-export-query-container.vala        |  122 ++++++++++++++++++++
 2 files changed, 123 insertions(+), 0 deletions(-)
---
diff --git a/src/plugins/media-export/Makefile.am b/src/plugins/media-export/Makefile.am
index ad35640..443b5de 100644
--- a/src/plugins/media-export/Makefile.am
+++ b/src/plugins/media-export/Makefile.am
@@ -20,6 +20,7 @@ librygel_media_export_la_SOURCES = rygel-media-export-plugin.vala \
 				   rygel-media-export-dummy-container.vala \
 				   rygel-media-export-dynamic-container.vala \
 				   rygel-media-export-root-container.vala \
+				   rygel-media-export-query-container.vala \
 				   rygel-media-export-dbus-service.vala \
 				   rygel-media-export-recursive-file-monitor.vala \
 				   rygel-media-export-harvester.vala \
diff --git a/src/plugins/media-export/rygel-media-export-query-container.vala b/src/plugins/media-export/rygel-media-export-query-container.vala
new file mode 100644
index 0000000..40d375b
--- /dev/null
+++ b/src/plugins/media-export/rygel-media-export-query-container.vala
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2009,2010 Jens Georg <mail jensge org>.
+ *
+ * This file is part of Rygel.
+ *
+ * Rygel is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Rygel is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+using Gee;
+using GUPnP;
+
+internal class Rygel.MediaExportQueryContainer : Rygel.MediaDBContainer {
+    private bool item_container;
+    private string column;
+    private string filter;
+    private SearchExpression expression;
+
+    public MediaExportQueryContainer (MediaDB media_db, string id, string name) {
+        // parse the id
+        // Following the schema:
+        // upnp:<class> -> get all of that class (eg. Albums)
+        // upnp:<class>,<item> -> get all that is contained in that class
+        // If an item suffix is present, the children are items, otherwise
+        // containers
+        // example: upnp:album -> All albums
+        //          upnp:album,The White Album -> All tracks of the White Album
+        //          upnp:author,The Beatles,upnp:album -> All Albums by the Beatles
+        //          the parts not prefixed by upnp: are URL-escaped
+        base (media_db, id, name);
+        var args = id.split(",");
+        if (args.length % 2 == 0) {
+            // we will contain items
+            this.item_container = true;
+            // TODO prepare search expression
+            var exp = new RelationalExpression ();
+            if (args[0] == "upnp:author")
+                exp.operand1 = "dc:creator";
+            else
+                exp.operand1 = args[0];
+            exp.op = SearchCriteriaOp.EQ;
+            exp.operand2 = args[1];
+            this.expression = exp;
+        } else {
+            this.filter = "";
+            this.item_container = false;
+            this.column = args[0].replace("upnp:", "");
+        }
+    }
+
+    public override async Gee.List<MediaObject>? search (
+                                        SearchExpression expression,
+                                        uint             offset,
+                                        uint             max_count,
+                                        out uint         total_matches,
+                                        Cancellable?     cancellable)
+                                        throws GLib.Error {
+        var exp = new LogicalExpression ();
+        exp.operand1 = this.expression;
+        exp.op = LogicalOperator.AND;
+        exp.operand2 = expression;
+        Gee.List<MediaObject> list;
+        var old_id = this.id;
+        this.id = "0";
+        list = yield base.search (exp, offset, max_count, out total_matches, cancellable);
+        this.id = old_id;
+        return list;
+    }
+
+    public override async Gee.List<MediaObject>? get_children (
+                                       uint             offset,
+                                       uint             max_count,
+                                       Cancellable?     cancellable)
+                                       throws GLib.Error {
+        if (item_container) {
+            uint foobar;
+            return yield this.search (this.expression,
+                                      offset,
+                                      max_count,
+                                      out foobar,
+                                      cancellable);
+        }
+
+        var children = new ArrayList<MediaObject> ();
+        try {
+        var data = this.media_db.get_meta_data_column_by_filter (
+                                       this.column,
+                                       this.filter,
+                                       new ValueArray (0),
+                                       offset,
+                                       max_count);
+       foreach (string foo in data) {
+            debug ("Got child: %s", foo);
+            if (foo == null)
+                continue;
+            var new_id = this.id + "," + foo;
+            var container = new MediaExportQueryContainer (this.media_db,
+                                                           new_id,
+                                                           foo);
+            container.parent = this;
+            container.parent_ref = this;
+            children.add (container);
+        }
+        } catch (GLib.Error err) {
+            warning ("Failed to query meta data: %s", err.message);
+            throw err;
+        }
+
+        return children;
+    }
+}