plugin: disable input to stage when screen is locked

This is a slightly modified version of jaapz' branch trying to make the method more general
by applying the lock in update_input_area. begin_modal will now set the the input area
to FULLSCREEN, so set_input_area is no longer required to be called from the windowoverview
or the workspaceview.

CMakeLists.txt

@@ -69,6 +69,7 @@ vala_precompile(VALA_C
     src/DragDropAction.vala
     src/Main.vala
     src/Plugin.vala
+    src/ScreenSaver.vala
     src/Settings.vala
     src/TextShadowEffect.vala
     src/Utils.vala

src/Plugin.vala

@@ -45,6 +45,8 @@ namespace Gala
 		WorkspaceView workspace_view;
 		Zooming zooming;
 		WindowOverview window_overview;
+
+		ScreenSaver? screensaver;
 		
 #if HAS_MUTTER38
 		// FIXME we need a proper-sized background for every monitor
@@ -87,6 +89,17 @@ namespace Gala
 			
 			DBus.init (this);
 			
+			// Due to a bug which enables access to the stage when using multiple monitors
+			// in the screensaver, we have to listen for changes and make sure the input area
+			// is set to NONE when we are in locked mode
+			try {
+				screensaver = Bus.get_proxy_sync (BusType.SESSION, "org.gnome.ScreenSaver",
+					"/org/gnome/ScreenSaver");
+				screensaver.active_changed.connect (() => {
+					update_input_area ();
+				});
+			} catch (Error e) { warning (e.message); }
+			
 			var stage = Compositor.get_stage_for_screen (screen) as Clutter.Stage;
 			
 			string color = new Settings ("org.gnome.desktop.background").get_string ("primary-color");
@@ -250,14 +263,22 @@ namespace Gala
 		public void update_input_area ()
 		{
 			var schema = BehaviorSettings.get_default ().schema;
+			var screen = get_screen ();
 			
-			if (schema.get_enum ("hotcorner-topleft") != ActionType.NONE ||
+			if (screensaver != null && screensaver.get_active ()) {
+				Utils.set_input_area (screen, InputArea.NONE);
+				return;
+			}
+			
+			if (modal_count > 0)
+				Utils.set_input_area (screen, InputArea.FULLSCREEN);
+			else if (schema.get_enum ("hotcorner-topleft") != ActionType.NONE ||
 				schema.get_enum ("hotcorner-topright") != ActionType.NONE ||
 				schema.get_enum ("hotcorner-bottomleft") != ActionType.NONE ||
 				schema.get_enum ("hotcorner-bottomright") != ActionType.NONE)
-				Utils.set_input_area (get_screen (), InputArea.HOT_CORNER);
+				Utils.set_input_area (screen, InputArea.HOT_CORNER);
 			else
-				Utils.set_input_area (get_screen (), InputArea.NONE);
+				Utils.set_input_area (screen, InputArea.NONE);
 		}
 		
 		public uint32[] get_all_xids ()
@@ -318,6 +339,7 @@ namespace Gala
 			var screen = get_screen ();
 			var display = screen.get_display ();
 			
+			update_input_area ();
 			base.begin_modal (x_get_stage_window (Compositor.get_stage_for_screen (screen)), {}, 0, display.get_current_time ());
 		}
 		
@@ -327,6 +349,7 @@ namespace Gala
 			if (modal_count > 0)
 				return;
 			
+			update_input_area ();
 			base.end_modal (get_screen ().get_display ().get_current_time ());
 		}
 		

src/ScreenSaver.vala

@@ -0,0 +1,27 @@
+//  
+//  Copyright (C) 2012 Jaap Broekhuizen
+// 
+//  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 3 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, see <http://www.gnu.org/licenses/>.
+// 
+
+namespace Gala
+{
+	[DBus (name = "org.gnome.ScreenSaver")]
+	public interface ScreenSaver : GLib.Object
+	{
+		public abstract bool get_active () throws GLib.IOError;
+		public signal void active_changed (bool active);
+	}
+
+}

src/Widgets/WindowOverview.vala

@@ -581,7 +581,6 @@ namespace Gala
 			grab_key_focus ();
 			
 			plugin.begin_modal ();
-			Utils.set_input_area (screen, InputArea.FULLSCREEN);
 			
 			visible = true;
 			

src/Widgets/WorkspaceView.vala

@@ -388,7 +388,6 @@ namespace Gala
 			visible = true;
 			grab_key_focus ();
 			
-			Utils.set_input_area (screen, InputArea.FULLSCREEN);
 			plugin.begin_modal ();
 			
 			var area = screen.get_monitor_geometry (screen.get_primary_monitor ());