=== modified file 'src/plugins/Makefile.am'
--- src/plugins/Makefile.am	2010-12-02 13:40:40 +0000
+++ src/plugins/Makefile.am	2010-12-04 18:59:57 +0000
@@ -31,6 +31,7 @@
 	dictionary.vala \
 	directory-plugin.vala \
 	gnome-session-plugin.vala \
+	gnome-screen-lock-plugin.vala \
 	hybrid-search-plugin.vala \
 	locate-plugin.vala \
 	rhythmbox-plugin.vala \

=== added file 'src/plugins/gnome-screen-lock-plugin.vala'
--- src/plugins/gnome-screen-lock-plugin.vala	1970-01-01 00:00:00 +0000
+++ src/plugins/gnome-screen-lock-plugin.vala	2010-12-04 19:00:05 +0000
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2010 Igor S. Mandrigin <i@mandrigin.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA.
+ *
+ * Based on plugins code by Michal Hruby <michal.mhr@gmail.com>
+ *
+ */
+
+namespace Synapse
+{
+  [DBus (name = "org.gnome.ScreenSaver")]
+  public interface GnomeScreenSaver: Object
+  {
+    public const string UNIQUE_NAME = "org.gnome.ScreenSaver";
+    public const string OBJECT_PATH = "/org/gnome/ScreenSaver";
+    public const string INTERFACE_NAME = "org.gnome.ScreenSaver";
+    
+    public abstract void lock () throws DBus.Error;
+  }
+    
+  public class GnomeScreenLockPlugin: DataPlugin
+  {
+    private class LockScreenAction: Object, Match
+    {
+      // for Match interface
+      public string title { get; construct set; }
+      public string description { get; set; default = ""; }
+      public string icon_name { get; construct set; default = ""; }
+      public bool has_thumbnail { get; construct set; default = false; }
+      public string thumbnail_path { get; construct set; }
+      public MatchType match_type { get; construct set; }
+
+      public LockScreenAction ()
+      {
+        Object (match_type: MatchType.ACTION, title: _ ("Lock Screen"),
+                description: _ ("Locks screen and starts screensaver, if any."),
+                icon_name: "system-lock-screen", has_thumbnail: false);
+      }
+      
+      public void execute (Match? match)
+      {
+        try
+        {
+          var connection = DBus.Bus.get (DBus.BusType.SESSION);
+          var dbus_interface = (GnomeScreenSaver)
+            connection.get_object (GnomeScreenSaver.UNIQUE_NAME,
+                                   GnomeScreenSaver.OBJECT_PATH,
+                                   GnomeScreenSaver.INTERFACE_NAME);
+
+          dbus_interface.lock ();
+        }
+        catch (DBus.Error err)
+        {
+          warning ("%s", err.message);
+        }
+      }
+    }
+
+    static void register_plugin ()
+    {
+      DataSink.PluginRegistry.get_default ().register_plugin (
+        typeof (GnomeScreenLockPlugin),
+        "Gnome screen lock plugin",
+        _ ("Allows you to lock screen of your computer."),
+        "system-lock-screen",
+        register_plugin,
+        DBusNameCache.get_default ().name_has_owner (GnomeScreenSaver.UNIQUE_NAME),
+        _ ("Gnome Screen Saver wasn't found")
+      );
+    }
+
+    static construct
+    {
+      register_plugin ();
+    }
+
+    private bool gnome_screensaver_available = false;
+    private Gee.List<Match> actions;
+
+    construct
+    {
+      var cache = DBusNameCache.get_default ();
+      gnome_screensaver_available = cache.name_has_owner (GnomeScreenSaver.UNIQUE_NAME);
+      debug ("%s %s available", GnomeScreenSaver.UNIQUE_NAME,
+        gnome_screensaver_available ? "is" : "isn't");
+      
+      actions = new Gee.LinkedList<Match> ();
+      actions.add (new LockScreenAction ());
+    }
+    
+    private DBus.Connection connection;
+    
+    public override async ResultSet? search (Query q) throws SearchError
+    {
+      if (!gnome_screensaver_available) return null;
+     // we only search for actions
+      if (!(QueryFlags.ACTIONS in q.query_type)) return null;
+
+      var result = new ResultSet ();
+
+      var matchers = Query.get_matchers_for_query (q.query_string, 0,
+        RegexCompileFlags.OPTIMIZE | RegexCompileFlags.CASELESS);
+
+      foreach (var action in actions)
+      {
+        foreach (var matcher in matchers)
+        {
+          if (matcher.key.match (action.title))
+          {
+            result.add (action, matcher.value - 5);
+            break;
+          }
+        }
+      }
+
+      q.check_cancellable ();
+
+      return result;
+    }
+  }
+}

=== modified file 'src/synapse-main.vala'
--- src/synapse-main.vala	2010-12-04 13:56:51 +0000
+++ src/synapse-main.vala	2010-12-04 19:01:43 +0000
@@ -116,6 +116,7 @@
         typeof (ZeitgeistPlugin),
         typeof (HybridSearchPlugin),
         //typeof (LocatePlugin),
+        typeof (GnomeScreenLockPlugin),
         typeof (GnomeSessionPlugin),
         typeof (UPowerPlugin),
         typeof (CommandPlugin),