[gnome-builder] gui: allow setting placeholder for frame

[Christian Hergert <chergert src gnome org>]

commit 9a682008dddcef851977fa7cec1a1b9c07efd875
Author: Christian Hergert <chergert redhat com>
Date:   Sat Apr 27 11:56:06 2019 -0700

    gui: allow setting placeholder for frame

 src/libide/gui/ide-frame.c | 31 +++++++++++++++++++------------
 src/libide/gui/ide-frame.h |  3 +++
 2 files changed, 22 insertions(+), 12 deletions(-)
---
diff --git a/src/libide/gui/ide-frame.c b/src/libide/gui/ide-frame.c
index 67c445cca..5387944ec 100644
--- a/src/libide/gui/ide-frame.c
+++ b/src/libide/gui/ide-frame.c
@@ -18,8 +18,6 @@
  * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
-
-
 #define G_LOG_DOMAIN "ide-frame"
 
 #include "config.h"
@@ -1421,20 +1419,12 @@ ide_frame_add_child (GtkBuildable *buildable,
                      const gchar  *type)
 {
   IdeFrame *self = (IdeFrame *)buildable;
-  IdeFramePrivate *priv = ide_frame_get_instance_private (self);
   GtkBuildableIface *parent = g_type_interface_peek_parent (GTK_BUILDABLE_GET_IFACE (buildable));
 
   if (g_strcmp0 (type, "placeholder") == 0 && GTK_IS_WIDGET (object))
-    {
-      gtk_container_foreach (GTK_CONTAINER (priv->empty_placeholder),
-                             (GtkCallback) gtk_widget_destroy,
-                             NULL);
-      gtk_container_add (GTK_CONTAINER (priv->empty_placeholder), GTK_WIDGET (object));
-    }
+    ide_frame_set_placeholder (self, GTK_WIDGET (object));
   else
-    {
-      parent->add_child (buildable, builder, object, type);
-    }
+    parent->add_child (buildable, builder, object, type);
 }
 
 static void
@@ -1442,3 +1432,20 @@ buildable_iface_init (GtkBuildableIface *iface)
 {
   iface->add_child = ide_frame_add_child;
 }
+
+void
+ide_frame_set_placeholder (IdeFrame  *self,
+                           GtkWidget *placeholder)
+{
+  IdeFramePrivate *priv = ide_frame_get_instance_private (self);
+
+  g_return_if_fail (IDE_IS_FRAME (self));
+  g_return_if_fail (!placeholder || GTK_IS_WIDGET (placeholder));
+
+  gtk_container_foreach (GTK_CONTAINER (priv->empty_placeholder),
+                         (GtkCallback) gtk_widget_destroy,
+                         NULL);
+
+  if (placeholder != NULL)
+    gtk_container_add (GTK_CONTAINER (priv->empty_placeholder), placeholder);
+}
diff --git a/src/libide/gui/ide-frame.h b/src/libide/gui/ide-frame.h
index 36e586d7c..8b4078e5a 100644
--- a/src/libide/gui/ide-frame.h
+++ b/src/libide/gui/ide-frame.h
@@ -80,5 +80,8 @@ IDE_AVAILABLE_IN_3_32
 void       ide_frame_add_with_depth        (IdeFrame             *self,
                                             GtkWidget            *widget,
                                             guint                 position);
+IDE_AVAILABLE_IN_3_34
+void       ide_frame_set_placeholder       (IdeFrame             *self,
+                                            GtkWidget            *placeholder);
 
 G_END_DECLS