[gtk+] Fail to scroll if the given mark is not in text view's current buffer

[Kristian Rietveld <kristian src gnome org>]

commit 7a3d98324df08cce17ee0ffce74c0fa73b38ee4a
Author: Kristian Rietveld <kris gtk org>
Date:   Fri Sep 4 13:34:56 2009 +0200

    Fail to scroll if the given mark is not in text view's current buffer
    
    In gtk_text_view_queue_scroll() we need to verify if the given mark
    exists in the text view's current buffer.  When not done, this can
    result in corruption of the BTree data structure.  Patch merged from
    maemo-gtk.

 gtk/gtktextview.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c
index 4c5f0d2..ad04480 100644
--- a/gtk/gtktextview.c
+++ b/gtk/gtktextview.c
@@ -1894,6 +1894,7 @@ gtk_text_view_queue_scroll (GtkTextView   *text_view,
                             gdouble        xalign,
                             gdouble        yalign)
 {
+  const char *mark_name;
   GtkTextIter iter;
   GtkTextPendingScroll *scroll;
 
@@ -1906,6 +1907,12 @@ gtk_text_view_queue_scroll (GtkTextView   *text_view,
   scroll->xalign = xalign;
   scroll->yalign = yalign;
   
+  /* We need to verify that the buffer contains the mark, otherwise this
+   * can lead to data structure corruption later on.
+   */
+  mark_name = gtk_text_mark_get_name (mark);
+  g_return_if_fail (gtk_text_buffer_get_mark (get_buffer (text_view), mark_name));
+
   gtk_text_buffer_get_iter_at_mark (get_buffer (text_view), &iter, mark);
 
   scroll->mark = gtk_text_buffer_create_mark (get_buffer (text_view),