[gedit] notebook: fix page switching bug when closing an unfocused tab

[Sébastien Wilmet <swilmet src gnome org>]

commit 334acf29ca5f9dcbed259bf5239e43f1aba1f0e7
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed Jun 10 13:46:40 2015 +0200

    notebook: fix page switching bug when closing an unfocused tab
    
    In gedit_notebook_page_removed(), the page was already removed, so
    calling gtk_notebook_get_current_page() there was wrong. It was maybe
    due to a GTK+ change.
    
    The list of focused pages contained only the previously focused pages,
    not the current one. This commit changes that to also include the
    currently focused page in the list, so in gedit_notebook_page_removed()
    we know if the page removed was the current page or not.
    
    Change also the order of the history, with the most recent focused page
    at the first element of the list instead of at the end, so we don't need
    to traverse the whole list each time.
    
    Make also the code more robust.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=731784

 gedit/gedit-notebook.c |   67 +++++++++++++++++++++++++++--------------------
 1 files changed, 38 insertions(+), 29 deletions(-)
---
diff --git a/gedit/gedit-notebook.c b/gedit/gedit-notebook.c
index 33f2104..c852315 100644
--- a/gedit/gedit-notebook.c
+++ b/gedit/gedit-notebook.c
@@ -3,6 +3,7 @@
  * This file is part of gedit
  *
  * Copyright (C) 2005 - Paolo Maggi
+ * Copyright (C) 2015 - Sébastien Wilmet
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -34,6 +35,9 @@
 
 struct _GeditNotebookPrivate
 {
+       /* History of focused pages. The first element contains the most recent
+        * one.
+        */
        GList *focused_pages;
 
        guint ignore_focused_page_update : 1;
@@ -211,23 +215,29 @@ gedit_notebook_switch_page (GtkNotebook *notebook,
 {
        GeditNotebookPrivate *priv = GEDIT_NOTEBOOK (notebook)->priv;
 
+       GTK_NOTEBOOK_CLASS (gedit_notebook_parent_class)->switch_page (notebook, page, page_num);
+
        if (!priv->ignore_focused_page_update)
        {
-               gint prev_page_num;
-               GtkWidget *prev_page;
-
-               prev_page_num = gtk_notebook_get_current_page (notebook);
-               prev_page = gtk_notebook_get_nth_page (notebook, prev_page_num);
+               gint page_num;
 
-               /* Remove the old page, we dont want to grow unnecessarily
-                * the list.
+               /* Get again page_num and page, the signal handler may have
+                * changed them.
                 */
-               priv->focused_pages = g_list_remove (priv->focused_pages, prev_page);
+               page_num = gtk_notebook_get_current_page (notebook);
+               if (page_num != -1)
+               {
+                       GtkWidget *page = gtk_notebook_get_nth_page (notebook, page_num);
+                       g_assert (page != NULL);
 
-               priv->focused_pages = g_list_append (priv->focused_pages, prev_page);
-       }
+                       /* Remove the old page, we dont want to grow unnecessarily
+                        * the list.
+                        */
+                       priv->focused_pages = g_list_remove (priv->focused_pages, page);
 
-       GTK_NOTEBOOK_CLASS (gedit_notebook_parent_class)->switch_page (notebook, page, page_num);
+                       priv->focused_pages = g_list_prepend (priv->focused_pages, page);
+               }
+       }
 
        /* give focus to the tab */
        gtk_widget_grab_focus (page);
@@ -251,24 +261,22 @@ close_button_clicked_cb (GeditTabLabel *tab_label,
 }
 
 static void
-smart_tab_switching_on_closure (GeditNotebook *notebook,
-                               GeditTab      *tab)
+switch_to_last_focused_page (GeditNotebook *notebook,
+                            GeditTab      *tab)
 {
-       if (notebook->priv->focused_pages)
+       if (notebook->priv->focused_pages != NULL)
        {
                GList *node;
-               GtkWidget *child;
+               GtkWidget *page;
                gint page_num;
 
-               /* activate the last focused tab */
-               node = g_list_last (notebook->priv->focused_pages);
-               child = GTK_WIDGET (node->data);
+               node = notebook->priv->focused_pages;
+               page = GTK_WIDGET (node->data);
 
-               page_num = gtk_notebook_page_num (GTK_NOTEBOOK (notebook),
-                                                 child);
+               page_num = gtk_notebook_page_num (GTK_NOTEBOOK (notebook), page);
+               g_return_if_fail (page_num != -1);
 
-               gtk_notebook_set_current_page (GTK_NOTEBOOK (notebook),
-                                              page_num);
+               gtk_notebook_set_current_page (GTK_NOTEBOOK (notebook), page_num);
        }
 }
 
@@ -289,7 +297,7 @@ gedit_notebook_page_removed (GtkNotebook *notebook,
 {
        GeditNotebookPrivate *priv = GEDIT_NOTEBOOK (notebook)->priv;
        GtkWidget *tab_label;
-       gint current_page;
+       gboolean current_page;
 
        tab_label = get_tab_label (GEDIT_TAB (page));
 
@@ -304,15 +312,16 @@ gedit_notebook_page_removed (GtkNotebook *notebook,
                                                      notebook);
        }
 
-       /* Remove the page from the focused pages list */
-       priv->focused_pages = g_list_remove (priv->focused_pages, page);
+       /* The page removed was the current page. */
+       current_page = (priv->focused_pages != NULL &&
+                       priv->focused_pages->data == page);
 
-       current_page = gtk_notebook_get_current_page (notebook);
+       priv->focused_pages = g_list_remove (priv->focused_pages, page);
 
-       if (page_num == current_page)
+       if (current_page)
        {
-               smart_tab_switching_on_closure (GEDIT_NOTEBOOK (notebook),
-                                               GEDIT_TAB (page));
+               switch_to_last_focused_page (GEDIT_NOTEBOOK (notebook),
+                                            GEDIT_TAB (page));
        }
 }