[dia] [scan-build] Null dereference ...

[Hans Breuer <hans src gnome org>]

commit c86d220930401ad2c67aa4d2d6141c6e5b2c69ad
Author: Hans Breuer <hans breuer org>
Date:   Sun Dec 13 17:53:42 2009 +0100

    [scan-build] Null dereference ...
    
    ... but only if screwed elsewhere. Hopefully the code is a
    bit more understandable now;)

 app/sheets_dialog_callbacks.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/app/sheets_dialog_callbacks.c b/app/sheets_dialog_callbacks.c
index 24bef02..5532a3a 100644
--- a/app/sheets_dialog_callbacks.c
+++ b/app/sheets_dialog_callbacks.c
@@ -93,8 +93,10 @@ sheets_dialog_up_down_set_sensitive(GList *wrapbox_button_list,
                                     GtkToggleButton *togglebutton)
 {
   GtkWidget *button;
+  GList *second;
 
   button = lookup_widget(sheets_dialog, "button_move_up");
+  g_return_if_fail(button != NULL);
 
   /* If the active button is the 1st in the wrapbox, OR
      if the active button is a linebreak AND is 2nd in the wrapbox
@@ -111,13 +113,12 @@ sheets_dialog_up_down_set_sensitive(GList *wrapbox_button_list,
     gtk_widget_set_sensitive(button, TRUE);
 
   button = lookup_widget(sheets_dialog, "button_move_down");
+  g_return_if_fail(button != NULL);
   if (!wrapbox_button_list
       || GTK_TOGGLE_BUTTON(g_list_last(wrapbox_button_list)->data) == togglebutton
       || (!g_object_get_data(G_OBJECT(togglebutton), "sheet_object_mod")
-          && g_list_previous(g_list_last(wrapbox_button_list))
-          && GTK_TOGGLE_BUTTON(g_list_previous(g_list_last(wrapbox_button_list))
-                              ->data)
-             == togglebutton))
+          && ((second = g_list_previous(g_list_last(wrapbox_button_list))) != NULL)
+          && GTK_TOGGLE_BUTTON(second->data) == togglebutton))
     gtk_widget_set_sensitive(button, FALSE);
   else
     gtk_widget_set_sensitive(button, TRUE);