[gtk/wip/baedert/some-api: 5/7] widget: Save the depth of a widget in the tree

[Timm Bäder <baedert src gnome org>]

commit 1cfbca09b5561e388e3978609e297027d82b3abe
Author: Timm Bäder <mail baedert org>
Date:   Tue Dec 25 11:44:18 2018 +0100

    widget: Save the depth of a widget in the tree
    
    This is handy whenever we do some operation on all parent widgets of a
    widget.

 gtk/gtkwidget.c        | 19 +++++++++++++++++++
 gtk/gtkwidgetprivate.h |  7 +++++++
 2 files changed, 26 insertions(+)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 4fadd96534..4e57d5e833 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -2802,6 +2802,7 @@ gtk_widget_init (GTypeInstance *instance, gpointer g_class)
   priv->last_child = NULL;
   priv->prev_sibling = NULL;
   priv->next_sibling = NULL;
+  priv->depth = 1;
   priv->allocated_baseline = -1;
   priv->allocated_size_baseline = -1;
 
@@ -2979,6 +2980,22 @@ gtk_widget_new (GType        type,
   return widget;
 }
 
+static void
+gtk_widget_propagate_depth (GtkWidget *widget,
+                            int        new_depth)
+{
+  GtkWidgetPrivate *priv = gtk_widget_get_instance_private (widget);
+  GtkWidget *child;
+
+  priv->depth = new_depth;
+
+  for (child = _gtk_widget_get_first_child (widget);
+       child != NULL;
+       child = _gtk_widget_get_next_sibling (child))
+    gtk_widget_propagate_depth (child, new_depth + 1);
+}
+
+
 /**
  * gtk_widget_unparent:
  * @widget: a #GtkWidget
@@ -3062,6 +3079,7 @@ gtk_widget_unparent (GtkWidget *widget)
   priv->parent = NULL;
   priv->prev_sibling = NULL;
   priv->next_sibling = NULL;
+  gtk_widget_propagate_depth (widget, 1);
 
   /* parent may no longer expand if the removed
    * child was expand=TRUE and could therefore
@@ -6505,6 +6523,7 @@ gtk_widget_reposition_after (GtkWidget *widget,
   gtk_widget_push_verify_invariants (widget);
 
   priv->parent = parent;
+  gtk_widget_propagate_depth (widget, gtk_widget_get_depth (parent) + 1);
 
   if (previous_sibling)
     {
diff --git a/gtk/gtkwidgetprivate.h b/gtk/gtkwidgetprivate.h
index f658811358..390fdc8a57 100644
--- a/gtk/gtkwidgetprivate.h
+++ b/gtk/gtkwidgetprivate.h
@@ -167,6 +167,7 @@ struct _GtkWidgetPrivate
   GtkWidget *next_sibling;
   GtkWidget *first_child;
   GtkWidget *last_child;
+  int depth;
 
   /* only created on-demand */
   GtkListListModel *children_observer;
@@ -481,6 +482,12 @@ _gtk_widget_get_last_child (GtkWidget *widget)
   return widget->priv->last_child;
 }
 
+static inline int
+gtk_widget_get_depth (GtkWidget *widget)
+{
+  return widget->priv->depth;
+}
+
 G_END_DECLS
 
 #endif /* __GTK_WIDGET_PRIVATE_H__ */