[gedit] multi notebook: factor out small utility

[Paolo Borelli <pborelli src gnome org>]

commit 1d405196ed79120f3217192c016899ea223b8030
Author: Paolo Borelli <pborelli gnome org>
Date:   Sun Sep 13 22:28:51 2015 +0200

    multi notebook: factor out small utility
    
    This also adds a missing g_object_notify when setting the active
    tab to NULL programmatically

 gedit/gedit-multi-notebook.c |   27 ++++++++++++++++-----------
 1 files changed, 16 insertions(+), 11 deletions(-)
---
diff --git a/gedit/gedit-multi-notebook.c b/gedit/gedit-multi-notebook.c
index 9214f92..7583c6f 100644
--- a/gedit/gedit-multi-notebook.c
+++ b/gedit/gedit-multi-notebook.c
@@ -311,6 +311,14 @@ notebook_page_reordered (GeditNotebook      *notebook,
 }
 
 static void
+set_active_tab (GeditMultiNotebook *mnb,
+                GeditTab           *tab)
+{
+       mnb->priv->active_tab = tab;
+       g_object_notify_by_pspec (G_OBJECT (mnb), properties[PROP_ACTIVE_TAB]);
+}
+
+static void
 notebook_page_removed (GtkNotebook        *notebook,
                       GtkWidget          *child,
                       guint               page_num,
@@ -326,8 +334,7 @@ notebook_page_removed (GtkNotebook        *notebook,
 
        if (mnb->priv->total_tabs == 0)
        {
-               mnb->priv->active_tab = NULL;
-               g_object_notify_by_pspec (G_OBJECT (mnb), properties[PROP_ACTIVE_TAB]);
+               set_active_tab (mnb, NULL);
        }
 
        g_signal_emit (G_OBJECT (mnb), signals[TAB_REMOVED], 0, notebook, tab);
@@ -380,11 +387,7 @@ notebook_switch_page (GtkNotebook        *book,
                GeditTab *old_tab;
 
                old_tab = mnb->priv->active_tab;
-
-               /* set the active tab */
-               mnb->priv->active_tab = tab;
-               g_object_notify_by_pspec (G_OBJECT (mnb), properties[PROP_ACTIVE_TAB]);
-
+               set_active_tab (mnb, tab);
                g_signal_emit (G_OBJECT (mnb), signals[SWITCH_TAB], 0,
                               mnb->priv->active_notebook, old_tab,
                               book, tab);
@@ -806,15 +809,17 @@ gedit_multi_notebook_set_active_tab (GeditMultiNotebook *mnb,
        g_return_if_fail (GEDIT_IS_MULTI_NOTEBOOK (mnb));
        g_return_if_fail (GEDIT_IS_TAB (tab) || tab == NULL);
 
-       if (tab == NULL)
+       /* use plain C cast since the active tab can be null */
+       if (tab == (GeditTab *) mnb->priv->active_tab)
        {
-               mnb->priv->active_tab = NULL;
-
                return;
        }
 
-       if (tab == GEDIT_TAB (mnb->priv->active_tab))
+       if (tab == NULL)
+       {
+               set_active_tab (mnb, NULL);
                return;
+       }
 
        l = mnb->priv->notebooks;