[libadwaita/wip/exalm/message-weak] message-dialog: Keep a weak pointer to the parent

[Alexander Mikhaylenko <alexm src gnome org>]

commit b8acdc01b625c7e6d2ca525983858e6f80269832
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Jul 26 15:43:09 2022 +0400

    message-dialog: Keep a weak pointer to the parent
    
    Don't crash if the parent gets destroyed first.

 src/adw-message-dialog.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
---
diff --git a/src/adw-message-dialog.c b/src/adw-message-dialog.c
index 4788746a..f6c3ea09 100644
--- a/src/adw-message-dialog.c
+++ b/src/adw-message-dialog.c
@@ -264,6 +264,16 @@ parent_unrealize_cb (AdwMessageDialog *self)
   priv->parent_height = -1;
 }
 
+static void
+parent_window_notify_cb (AdwMessageDialog *self)
+{
+  AdwMessageDialogPrivate *priv = adw_message_dialog_get_instance_private (self);
+
+  priv->parent_window = NULL;
+  priv->parent_width = -1;
+  priv->parent_height = -1;
+}
+
 static void
 set_parent (AdwMessageDialog *self,
             GtkWindow        *parent)
@@ -283,11 +293,19 @@ set_parent (AdwMessageDialog *self,
 
     if (gtk_widget_get_realized (GTK_WIDGET (priv->parent_window)))
       parent_unrealize_cb (self);
+
+    g_object_weak_unref (G_OBJECT (priv->parent_window),
+                         (GWeakNotify) parent_window_notify_cb,
+                         self);
   }
 
   priv->parent_window = parent;
 
   if (priv->parent_window) {
+    g_object_weak_ref (G_OBJECT (priv->parent_window),
+                       (GWeakNotify) parent_window_notify_cb,
+                       self);
+
     if (gtk_widget_get_realized (GTK_WIDGET (priv->parent_window)))
       parent_realize_cb (self);