[gnome-shell] [StContainer] Add :first-child, :last-child pseudo classes

[Florian Müllner <fmuellner src gnome org>]

commit 0905940ef84cc4943873a4615eb495a0a103c942
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Jul 22 23:08:45 2010 +0200

    [StContainer] Add :first-child, :last-child pseudo classes
    
    Add support for the CSS :first-child and :last-child properties to
    StContainer, and thus to all containers in St and ShellGenericContainer.
    
    The internal ordering of the container's children is used to determine
    the child to which to attach the pseudo class, not the children's
    positions. This means that containers where positions can differ from
    the ordering (ShellGenericContainer / StGroup) may behave unexpectedly,
    so some caution is required.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=625316

 src/st/st-container.c |   69 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 69 insertions(+), 0 deletions(-)
---
diff --git a/src/st/st-container.c b/src/st/st-container.c
index 32083e0..10a48c7 100644
--- a/src/st/st-container.c
+++ b/src/st/st-container.c
@@ -35,6 +35,8 @@
 struct _StContainerPrivate
 {
   GList *children;
+  ClutterActor *first_child;
+  ClutterActor *last_child;
 };
 
 static void clutter_container_iface_init (ClutterContainerIface *iface);
@@ -43,6 +45,54 @@ G_DEFINE_ABSTRACT_TYPE_WITH_CODE (StContainer, st_container, ST_TYPE_WIDGET,
                                   G_IMPLEMENT_INTERFACE (CLUTTER_TYPE_CONTAINER,
                                                          clutter_container_iface_init));
 
+static void
+st_container_update_pseudo_classes (StContainer *container)
+{
+  GList *first_item, *last_item;
+  ClutterActor *first_child, *last_child;
+  StContainerPrivate *priv = container->priv;
+
+  first_item = priv->children;
+  first_child = first_item ? first_item->data : NULL;
+  if (first_child != priv->first_child)
+    {
+      if (priv->first_child && ST_IS_WIDGET (priv->first_child))
+        st_widget_remove_style_pseudo_class (ST_WIDGET (priv->first_child),
+                                             "first-child");
+      if (priv->first_child)
+        {
+          g_object_unref (priv->first_child);
+          priv->first_child = NULL;
+        }
+
+      if (first_child && ST_IS_WIDGET (first_child))
+        st_widget_add_style_pseudo_class (ST_WIDGET (first_child),
+                                          "first-child");
+      if (first_child)
+        priv->first_child = g_object_ref (first_child);
+    }
+
+  last_item = g_list_last (priv->children);
+  last_child = last_item ? last_item->data : NULL;
+  if (last_child != priv->last_child)
+    {
+      if (priv->last_child && ST_IS_WIDGET (priv->last_child))
+        st_widget_remove_style_pseudo_class (ST_WIDGET (priv->last_child),
+                                             "last-child");
+      if (priv->last_child)
+        {
+          g_object_unref (priv->last_child);
+          priv->last_child = NULL;
+        }
+
+      if (last_child && ST_IS_WIDGET (last_child))
+        st_widget_add_style_pseudo_class (ST_WIDGET (last_child),
+                                          "last-child");
+      if (last_child)
+        priv->last_child = g_object_ref (last_child);
+    }
+}
+
 /**
  * st_container_remove_all:
  * @container: An #StContainer
@@ -62,6 +112,7 @@ st_container_remove_all (StContainer *container)
 
       clutter_container_remove_actor (CLUTTER_CONTAINER (container), child);
     }
+  st_container_update_pseudo_classes (container);
 }
 
 /**
@@ -104,6 +155,9 @@ st_container_move_child (StContainer  *container,
 
   priv->children = g_list_delete_link (priv->children, item);
   priv->children = g_list_insert (priv->children, actor, pos);
+
+  st_container_update_pseudo_classes (container);
+
   clutter_actor_queue_relayout ((ClutterActor*) container);
 }
 
@@ -159,6 +213,7 @@ st_container_add (ClutterContainer *container,
   g_signal_emit_by_name (container, "actor-added", actor);
 
   clutter_container_sort_depth_order (container);
+  st_container_update_pseudo_classes (ST_CONTAINER (container));
 
   g_object_unref (actor);
 }
@@ -185,6 +240,8 @@ st_container_remove (ClutterContainer *container,
    */
   g_signal_emit_by_name (container, "actor-removed", actor);
 
+  st_container_update_pseudo_classes (ST_CONTAINER (container));
+
   if (CLUTTER_ACTOR_IS_VISIBLE (container))
     clutter_actor_queue_redraw (CLUTTER_ACTOR (container));
 
@@ -248,6 +305,8 @@ st_container_raise (ClutterContainer *container,
       clutter_actor_set_depth (actor, clutter_actor_get_depth (sibling));
     }
 
+  st_container_update_pseudo_classes (ST_CONTAINER (container));
+
   if (CLUTTER_ACTOR_IS_VISIBLE (container))
     clutter_actor_queue_redraw (CLUTTER_ACTOR (container));
 }
@@ -289,6 +348,8 @@ st_container_lower (ClutterContainer *container,
       clutter_actor_set_depth (actor, clutter_actor_get_depth (sibling));
     }
 
+  st_container_update_pseudo_classes (ST_CONTAINER (container));
+
   if (CLUTTER_ACTOR_IS_VISIBLE (container))
     clutter_actor_queue_redraw (CLUTTER_ACTOR (container));
 }
@@ -317,6 +378,14 @@ st_container_dispose (GObject *object)
       priv->children = NULL;
     }
 
+  if (priv->first_child)
+    g_object_unref (priv->first_child);
+  priv->first_child = NULL;
+
+  if (priv->last_child)
+    g_object_unref (priv->last_child);
+  priv->last_child = NULL;
+
   G_OBJECT_CLASS (st_container_parent_class)->dispose (object);
 }