[glade/headerbar: 7/8] GtkHeaderBar: Improving child add/remove/replace support

[Tristan Van Berkom <tvb src gnome org>]

commit c59573813e1739f0b229121202ed0e405f4fd4cd
Author: Tristan Van Berkom <tristan upstairslabs com>
Date:   Wed Nov 5 20:08:32 2014 +0900

    GtkHeaderBar: Improving child add/remove/replace support
    
      o Removed misguided code block in ->add_child()
    
        The said code block assumes that any placeholder being added
        should be added at the end 'if' anything is at the start.
    
        This big block of code makes things seem to work if you happened
        to save the file with one placeholder on each side (sneaky), however
        just breaks down when you save more than one placeholder at the
        beginning.
    
        In any case, the number of placeholders should be synchronized to
        the "start-size" / "end-size" properties (minus the number of real
        children which should be placed according to their "position"
        packing property).
    
      o Removed destructive calls to gtk_widget_destroy(), widgets are
        not destroyed unless the project is finalized or the final reference
        to them is part of a GladeCommand that is being cleared from the
        undo/redo stack
    
      o Ensure that the replacement placeholder added when ->remove_child()
        is called has the special child type set if it's the title widget
        (not sure if this is needed, but it doesnt hurt).

 plugins/gtk+/glade-gtk-header-bar.c |  144 ++++++++++++++++++-----------------
 1 files changed, 75 insertions(+), 69 deletions(-)
---
diff --git a/plugins/gtk+/glade-gtk-header-bar.c b/plugins/gtk+/glade-gtk-header-bar.c
index a7bf6c3..eee8e29 100644
--- a/plugins/gtk+/glade-gtk-header-bar.c
+++ b/plugins/gtk+/glade-gtk-header-bar.c
@@ -7,6 +7,10 @@
 
 #define TITLE_DISABLED_MESSAGE _("This property does not apply when a custom title is set")
 
+/* Uncomment to enable debug tracing of add/remove/replace children */
+//#define d(x) x
+#define d(x)
+
 static gint
 glade_gtk_header_bar_get_num_children (GObject *hb, GtkPackType type)
 {
@@ -67,62 +71,6 @@ glade_gtk_header_bar_post_create (GladeWidgetAdaptor *adaptor,
 }
 
 void
-glade_gtk_header_bar_add_child (GladeWidgetAdaptor *adaptor,
-                                GObject *parent,
-                                GObject *child)
-{
-  GladeWidget *gbox, *gchild;
-  GtkPackType pack_type;
-  gint num_children;
-  gchar *special_child_type;
-
-  gchild = glade_widget_get_from_gobject (child);
-  if (gchild)
-    glade_widget_set_pack_action_visible (gchild, "remove_slot", FALSE);
-
-  special_child_type = g_object_get_data (child, "special-child-type");
-  if (special_child_type && !strcmp (special_child_type, "title"))
-    {
-      gtk_header_bar_set_custom_title (GTK_HEADER_BAR (parent), GTK_WIDGET (child));
-      return;
-    }
-
-    // check if its a placeholder being added, and add it to the end if anything is at the start
-    if (GLADE_IS_PLACEHOLDER (child))
-      {
-        GList *list = gtk_container_get_children (GTK_CONTAINER (parent));
-        GList *l;
-        if (list)
-          {
-            for (l = list; l; l = l->next)
-              {
-                GObject *c = l->data;
-                GtkPackType t;
-                gtk_container_child_get (GTK_CONTAINER (parent), GTK_WIDGET (c), "pack-type", &t, NULL);
-                if (t == GTK_PACK_START)
-                  {
-                    gtk_header_bar_pack_end (GTK_HEADER_BAR (parent), GTK_WIDGET (child) );
-                    g_list_free (list);
-                    return;
-                  }
-              }
-            g_list_free (list);
-          }
-      }
-
-    GWA_GET_CLASS (GTK_TYPE_CONTAINER)->add (adaptor, parent, child);
-  
-  gbox = glade_widget_get_from_gobject (parent);
-
-  gtk_container_child_get (GTK_CONTAINER (parent), GTK_WIDGET (child), "pack-type", &pack_type, NULL);
-  num_children = glade_gtk_header_bar_get_num_children (parent, pack_type);
-  if (pack_type == GTK_PACK_START)
-    glade_widget_property_set (gbox, "start-size", num_children);
-  else
-    glade_widget_property_set (gbox, "end-size", num_children);
-}
-
-void
 glade_gtk_header_bar_action_activate (GladeWidgetAdaptor *adaptor,
                                       GObject * object,
                                       const gchar *action_path)
@@ -232,6 +180,10 @@ glade_gtk_header_bar_set_size (GObject * object,
 
   g_return_if_fail (GTK_IS_HEADER_BAR (object));
 
+  d(g_message ("Setting %s size to %d",
+              type == GTK_PACK_START ? "start" : "end",
+              g_value_get_int (value)));
+
   if (glade_util_object_is_loading (object))
     return;
 
@@ -272,9 +224,10 @@ glade_gtk_header_bar_set_size (GObject * object,
       if (!g_object_get_data (G_OBJECT (child), "remove-this"))
         continue;
 
-      g_object_ref (G_OBJECT (child));
+      g_object_set_data (G_OBJECT (child), "remove-this", GINT_TO_POINTER (0));
+
       gtk_container_remove (GTK_CONTAINER (object), child);
-      gtk_widget_destroy (child);
+
       old_size--;
     }
   for (l = g_list_last (children); l && old_size > new_size; l = l->prev)
@@ -284,9 +237,8 @@ glade_gtk_header_bar_set_size (GObject * object,
           !GLADE_IS_PLACEHOLDER (child))
         continue;
 
-      g_object_ref (G_OBJECT (child));
       gtk_container_remove (GTK_CONTAINER (object), child);
-      gtk_widget_destroy (child);
+
       old_size--;
     }
 
@@ -372,32 +324,80 @@ glade_gtk_header_bar_set_property (GladeWidgetAdaptor * adaptor,
 }
 
 void
+glade_gtk_header_bar_add_child (GladeWidgetAdaptor *adaptor,
+                                GObject *parent,
+                                GObject *child)
+{
+  GladeWidget *gbox, *gchild;
+  gint size;
+  gchar *special_child_type;
+
+  gchild = glade_widget_get_from_gobject (child);
+  if (gchild)
+    glade_widget_set_pack_action_visible (gchild, "remove_slot", FALSE);
+
+  special_child_type = g_object_get_data (child, "special-child-type");
+
+  d(g_message ("Add %s %p (special: %s)",
+              GLADE_IS_PLACEHOLDER (child) ? "placeholder" : "child",
+              child, special_child_type));
+
+  if (special_child_type && !strcmp (special_child_type, "title"))
+    {
+      gtk_header_bar_set_custom_title (GTK_HEADER_BAR (parent), GTK_WIDGET (child));
+      return;
+    }
+
+  GWA_GET_CLASS (GTK_TYPE_CONTAINER)->add (adaptor, parent, child);
+  
+  gbox = glade_widget_get_from_gobject (parent);
+  if (!glade_widget_superuser ())
+    {
+      glade_widget_property_get (gbox, "start-size", &size);
+      glade_widget_property_set (gbox, "start-size", size);
+
+      glade_widget_property_get (gbox, "end-size", &size);
+      glade_widget_property_set (gbox, "end-size", size);
+    }
+}
+
+void
 glade_gtk_header_bar_remove_child (GladeWidgetAdaptor * adaptor,
                                    GObject * object,
                                    GObject * child)
 {
   GladeWidget *gbox;
-  gint num_children;
-  GtkPackType pack_type;
+  gint size;
   gchar *special_child_type;
 
   special_child_type = g_object_get_data (child, "special-child-type");
+
+  d(g_message ("Remove %s %p (special: %s)", 
+              GLADE_IS_PLACEHOLDER (child) ? "placeholder" : "child",
+              child, special_child_type));
+
   if (special_child_type && !strcmp (special_child_type, "title"))
     {
-      gtk_header_bar_set_custom_title (GTK_HEADER_BAR (object), glade_placeholder_new ());
+      GtkWidget *replacement = glade_placeholder_new ();
+
+      g_object_set_data (G_OBJECT (replacement), "special-child-type", "title");
+      gtk_header_bar_set_custom_title (GTK_HEADER_BAR (object), replacement);
       return;
     }
   
-  gbox = glade_widget_get_from_gobject (object);
-
-  gtk_container_child_get (GTK_CONTAINER (object), GTK_WIDGET (child), "pack-type", &pack_type, NULL);
-
   gtk_container_remove (GTK_CONTAINER (object), GTK_WIDGET (child));
 
+  /* Synchronize number of placeholders, this should trigger the set_property method with the
+   * correct value (not the arbitrary number of children currently in the headerbar)
+   */
+  gbox = glade_widget_get_from_gobject (object);
   if (!glade_widget_superuser ())
     {
-      num_children = glade_gtk_header_bar_get_num_children (object, pack_type);
-      glade_widget_property_set (gbox, "start-size", num_children);
+      glade_widget_property_get (gbox, "start-size", &size);
+      glade_widget_property_set (gbox, "start-size", size);
+
+      glade_widget_property_get (gbox, "end-size", &size);
+      glade_widget_property_set (gbox, "end-size", size);
     }
 }
 
@@ -412,6 +412,12 @@ glade_gtk_header_bar_replace_child (GladeWidgetAdaptor * adaptor,
   special_child_type =
     g_object_get_data (G_OBJECT (current), "special-child-type");
 
+  d(g_message ("Replace %s %p (special: %s) with %s %p",
+              GLADE_IS_PLACEHOLDER (current) ? "placeholder" : "child",
+              current, special_child_type,
+              GLADE_IS_PLACEHOLDER (new_widget) ? "placeholder" : "child",
+              new_widget));
+
   if (special_child_type && !strcmp (special_child_type, "title"))
     {
       g_object_set_data (G_OBJECT (new_widget), "special-child-type", "title");