Add a MetaScreen:restacked signal and expose MetaWindow.layer

Expose restacking and a window's stack layer to allow a compositor
to insert elements into the window stack in the right location.
(See Bug 571827 – hide panel when screensaver is active)

src/core/stack.h src/include/common.h: Move MetaStackLayer to
 a public header.

src/core/screen.c src/core/screen-private.h src/core/stack.c:
 Add a ::restacked signal emitted after we finish restracking.

src/core/window.h src/include/window.h: Add meta_window_get_layer()

src/core/screen-private.h

@@ -144,6 +144,8 @@ struct _MetaScreen
 struct _MetaScreenClass
 {
   GObjectClass parent_class;
+
+  void (*restacked) (MetaScreen *);
 };
 
 MetaScreen*   meta_screen_new                 (MetaDisplay                *display,
@@ -229,4 +231,6 @@ gboolean meta_screen_apply_startup_properties (MetaScreen *screen,
                                                MetaWindow *window);
 void	 meta_screen_composite_all_windows (MetaScreen *screen);
 
+void     meta_screen_restacked (MetaScreen *screen);
+
 #endif

src/core/screen.c

@@ -74,6 +74,15 @@ enum
   PROP_N_WORKSPACES = 1
 };
 
+enum
+{
+  RESTACKED,
+
+  LAST_SIGNAL
+};
+
+static guint screen_signals[LAST_SIGNAL] = { 0 };
+
 G_DEFINE_TYPE (MetaScreen, meta_screen, G_TYPE_OBJECT);
 
 static void
@@ -129,6 +138,15 @@ meta_screen_class_init (MetaScreenClass *klass)
   object_class->set_property = meta_screen_set_property;
   object_class->finalize = meta_screen_finalize;
 
+  screen_signals[RESTACKED] =
+    g_signal_new ("restacked",
+                  G_TYPE_FROM_CLASS (object_class),
+                  G_SIGNAL_RUN_LAST,
+                  G_STRUCT_OFFSET (MetaScreenClass, restacked),
+                  NULL, NULL,
+                  g_cclosure_marshal_VOID__VOID,
+                  G_TYPE_NONE, 0);
+
   pspec = g_param_spec_int ("n-workspaces",
                             "N Workspaces",
                             "Number of workspaces",
@@ -2997,3 +3015,9 @@ meta_screen_get_active_workspace (MetaScreen *screen)
 {
   return screen->active_workspace;
 }
+
+void
+meta_screen_restacked (MetaScreen *screen)
+{
+  g_signal_emit (screen, screen_signals[RESTACKED], 0);
+}

src/core/stack.c

@@ -1287,6 +1287,8 @@ stack_sync_to_server (MetaStack *stack)
     g_array_free (stack->last_root_children_stacked, TRUE);
   stack->last_root_children_stacked = root_children_stacked;
   
+  meta_screen_restacked (stack->screen);
+
   /* That was scary... */
 }
 

src/core/stack.h

@@ -43,23 +43,6 @@
 
 #include "screen-private.h"
 
-/**
- * Layers a window can be in.
- * These MUST be in the order of stacking.
- */
-typedef enum
-{
-  META_LAYER_DESKTOP	       = 0,
-  META_LAYER_BOTTOM	       = 1,
-  META_LAYER_NORMAL	       = 2,
-  META_LAYER_TOP	       = 4, /* Same as DOCK; see EWMH and bug 330717 */
-  META_LAYER_DOCK	       = 4,
-  META_LAYER_FULLSCREEN	       = 5,
-  META_LAYER_FOCUSED_WINDOW    = 6,
-  META_LAYER_OVERRIDE_REDIRECT = 7,
-  META_LAYER_LAST	       = 8
-} MetaStackLayer;
-
 /**
  * A sorted list of windows bearing some level of resemblance to the stack of
  * windows on the X server.

src/core/window.c

@@ -8673,3 +8673,8 @@ meta_window_get_role (MetaWindow *window)
   return window->role;
 }
 
+MetaStackLayer
+meta_window_get_layer (MetaWindow *window)
+{
+  return window->layer;
+}

src/include/common.h

@@ -289,4 +289,21 @@ struct _MetaButtonLayout
   (ycoord) >= (rect).y &&                   \
   (ycoord) <  ((rect).y + (rect).height))
 
+/**
+ * Layers a window can be in.
+ * These MUST be in the order of stacking.
+ */
+typedef enum
+{
+  META_LAYER_DESKTOP	       = 0,
+  META_LAYER_BOTTOM	       = 1,
+  META_LAYER_NORMAL	       = 2,
+  META_LAYER_TOP	       = 4, /* Same as DOCK; see EWMH and bug 330717 */
+  META_LAYER_DOCK	       = 4,
+  META_LAYER_FULLSCREEN	       = 5,
+  META_LAYER_FOCUSED_WINDOW    = 6,
+  META_LAYER_OVERRIDE_REDIRECT = 7,
+  META_LAYER_LAST	       = 8
+} MetaStackLayer;
+
 #endif

src/include/window.h

@@ -97,6 +97,7 @@ GObject *meta_window_get_compositor_private (MetaWindow *window);
 void meta_window_set_compositor_private (MetaWindow *window, GObject *priv);
 void meta_window_configure_notify (MetaWindow *window, XConfigureEvent *event);
 const char *meta_window_get_role (MetaWindow *window);
+MetaStackLayer meta_window_get_layer (MetaWindow *window);
 MetaWindow* meta_window_find_root_ancestor    (MetaWindow *window);
 
 #endif