[gtk/bin-removal: 25/40] overlay: Derive from GtkWidget

[Matthias Clasen <matthiasc src gnome org>]

commit edd5d36159df7e88d1c295ad8fd2f1f6fe52aad9
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun May 3 10:50:56 2020 -0400

    overlay: Derive from GtkWidget
    
    We want to remove GtkBin and GtkContainer as they don't
    provide much useful functionality anymore.
    
    See #2681

 gtk/gtkoverlay.c | 121 +++++++++++++++++++++++++------------------------------
 gtk/gtkoverlay.h |   2 +-
 2 files changed, 56 insertions(+), 67 deletions(-)
---
diff --git a/gtk/gtkoverlay.c b/gtk/gtkoverlay.c
index 45277bad44..6d4962dbb6 100644
--- a/gtk/gtkoverlay.c
+++ b/gtk/gtkoverlay.c
@@ -83,19 +83,21 @@ typedef struct _GtkOverlayClass GtkOverlayClass;
 
 struct _GtkOverlay
 {
-  GtkBin parent_instance;
+  GtkWidget parent_instance;
+
+  GtkWidget *child;
 };
 
 struct _GtkOverlayClass
 {
-  GtkBinClass parent_class;
+  GtkWidgetClass parent_class;
 
   gboolean (*get_child_position) (GtkOverlay    *overlay,
                                   GtkWidget     *widget,
                                   GtkAllocation *allocation);
 };
 
-G_DEFINE_TYPE_WITH_CODE (GtkOverlay, gtk_overlay, GTK_TYPE_BIN,
+G_DEFINE_TYPE_WITH_CODE (GtkOverlay, gtk_overlay, GTK_TYPE_WIDGET,
                          G_IMPLEMENT_INTERFACE (GTK_TYPE_BUILDABLE,
                                                 gtk_overlay_buildable_init))
 
@@ -183,54 +185,6 @@ gtk_overlay_get_child_position (GtkOverlay    *overlay,
   return TRUE;
 }
 
-static void
-gtk_overlay_add (GtkContainer *container,
-                 GtkWidget    *widget)
-{
-
-  /* We only get into this path if we have no child
-   * (since GtkOverlay is a GtkBin) and the only child
-   * we can add through gtk_container_add is the main child,
-   * which we want to keep the lowest in the hierarchy.
-   */
-  gtk_widget_insert_after (widget, GTK_WIDGET (container), NULL);
-  _gtk_bin_set_child (GTK_BIN (container), widget);
-}
-
-static void
-gtk_overlay_remove (GtkContainer *container,
-                    GtkWidget    *widget)
-{
-  GtkWidget *main_child = gtk_bin_get_child (GTK_BIN (container));
-
-  if (widget == main_child)
-    {
-      GTK_CONTAINER_CLASS (gtk_overlay_parent_class)->remove (container, widget);
-    }
-  else
-    {
-      gtk_widget_unparent (widget);
-    }
-}
-
-static void
-gtk_overlay_forall (GtkContainer *overlay,
-                    GtkCallback   callback,
-                    gpointer      callback_data)
-{
-  GtkWidget *child;
-
-  child = gtk_widget_get_first_child (GTK_WIDGET (overlay));
-  while (child != NULL)
-    {
-      GtkWidget *next = gtk_widget_get_next_sibling (child);
-
-      (* callback) (child, callback_data);
-
-      child = next;
-    }
-}
-
 static void
 gtk_overlay_snapshot_child (GtkWidget   *overlay,
                             GtkWidget   *child,
@@ -310,21 +264,54 @@ gtk_overlay_set_property (GObject      *object,
     }
 }
 
+static void
+gtk_overlay_dispose (GObject *object)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (object);
+  GtkWidget *child;
+
+  g_clear_pointer (&overlay->child, gtk_widget_unparent);
+
+  while ((child = gtk_widget_get_first_child (GTK_WIDGET (overlay))))
+    gtk_widget_unparent (child);
+
+  G_OBJECT_CLASS (gtk_overlay_parent_class)->dispose (object);
+}
+
+static void
+gtk_overlay_compute_expand (GtkWidget *widget,
+                            gboolean  *hexpand,
+                            gboolean  *vexpand)
+{
+  GtkOverlay *overlay = GTK_OVERLAY (widget);
+
+  if (overlay->child)
+    {
+      *hexpand = gtk_widget_compute_expand (overlay->child, GTK_ORIENTATION_HORIZONTAL);
+      *vexpand = gtk_widget_compute_expand (overlay->child, GTK_ORIENTATION_VERTICAL);
+    }
+  else
+    {
+      *hexpand = FALSE;
+      *vexpand = FALSE;
+    }
+}
+
 static void
 gtk_overlay_class_init (GtkOverlayClass *klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
   GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
-  GtkContainerClass *container_class = GTK_CONTAINER_CLASS (klass);
+
+  object_class->dispose = gtk_overlay_dispose;
 
   object_class->get_property = gtk_overlay_get_property;
   object_class->set_property = gtk_overlay_set_property;
 
   widget_class->snapshot = gtk_overlay_snapshot;
-
-  container_class->add = gtk_overlay_add;
-  container_class->remove = gtk_overlay_remove;
-  container_class->forall = gtk_overlay_forall;
+  widget_class->compute_expand = gtk_overlay_compute_expand;
+  widget_class->grab_focus = gtk_widget_grab_focus_none;
+  widget_class->focus = gtk_widget_focus_child;
 
   klass->get_child_position = gtk_overlay_get_child_position;
 
@@ -396,11 +383,7 @@ gtk_overlay_buildable_add_child (GtkBuildable *buildable,
       if (type && strcmp (type, "overlay") == 0)
         gtk_overlay_add_overlay (GTK_OVERLAY (buildable), GTK_WIDGET (child));
       else if (!type)
-        {
-          /* Make sure the main-child node is the first one */
-          gtk_widget_insert_after (GTK_WIDGET (child), GTK_WIDGET (buildable), NULL);
-          _gtk_bin_set_child (GTK_BIN (buildable), GTK_WIDGET (child));
-        }
+        gtk_overlay_set_child (GTK_OVERLAY (buildable), GTK_WIDGET (child));
       else
         GTK_BUILDER_WARN_INVALID_CHILD_TYPE (buildable, type);
     }
@@ -572,10 +555,16 @@ gtk_overlay_set_child (GtkOverlay *overlay,
   g_return_if_fail (GTK_IS_OVERLAY (overlay));
   g_return_if_fail (child == NULL || GTK_IS_WIDGET (child));
 
-  if (gtk_bin_get_child (GTK_BIN (overlay)))
-    gtk_container_remove (GTK_CONTAINER (overlay), gtk_bin_get_child (GTK_BIN (overlay)));
-  else
-    gtk_container_add (GTK_CONTAINER (overlay), child);
+  g_clear_pointer (&overlay->child, gtk_widget_unparent);
+
+  overlay->child = child;
+
+  if (child)
+    {
+      /* Make sure the main-child node is the first one */
+      gtk_widget_insert_after (child, GTK_WIDGET (overlay), NULL);
+    }
+
   g_object_notify (G_OBJECT (overlay), "child");
 }
 
@@ -592,5 +581,5 @@ gtk_overlay_get_child (GtkOverlay *overlay)
 {
   g_return_val_if_fail (GTK_IS_OVERLAY (overlay), NULL);
 
-  return gtk_bin_get_child (GTK_BIN (overlay));
+  return overlay->child;
 }
diff --git a/gtk/gtkoverlay.h b/gtk/gtkoverlay.h
index 65b0412b36..f24365c8a4 100644
--- a/gtk/gtkoverlay.h
+++ b/gtk/gtkoverlay.h
@@ -25,7 +25,7 @@
 #error "Only <gtk/gtk.h> can be included directly."
 #endif
 
-#include <gtk/gtkbin.h>
+#include <gtk/gtkwidget.h>
 
 G_BEGIN_DECLS