From 0905940ef84cc4943873a4615eb495a0a103c942 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Florian=20M=C3=BCllner?= <fmuellner@gnome.org>
Date: Thu, 22 Jul 2010 23:08:45 +0200
Subject: [PATCH] [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 file changed, 69 insertions(+)

diff --git a/src/st/st-container.c b/src/st/st-container.c
index 32083e014..10a48c76a 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);
 }