Empty the bidi cache "stack" when it->sp is zeroed.

Solves crashes due to overflow of bidi cache stack.
Make sure cache is saved and restored around all temporary iterations.

 src/dispnew.c (buffer_posn_from_coords): Save and restore the bidi
 cache around display iteration.
 src/window.c (Fwindow_end, window_scroll_pixel_based)
 (displayed_window_lines, Frecenter): Save and restore the bidi
 cache around display iteration.
 src/bidi.c (bidi_unshelve_cache): Ensure we have enough space before
 restoring the shelved cache.
 (bidi_cache_ensure_space): Don't assume the required size is just
 one BIDI_CACHE_CHUNK away.
 src/xdisp.c (back_to_previous_visible_line_start, reseat_1)
 (init_iterator): Empty the bidi cache "stack".

1 files changed, 17 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index fdb6657e135..55ff323ab57 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,20 @@
+2011-07-05  Eli Zaretskii  <eliz@gnu.org>
+
+        * dispnew.c (buffer_posn_from_coords): Save and restore the bidi
+        cache around display iteration.
+
+        * window.c (Fwindow_end, window_scroll_pixel_based)
+        (displayed_window_lines, Frecenter): Save and restore the bidi
+        cache around display iteration.
+
+        * bidi.c (bidi_unshelve_cache): Ensure we have enough space before
+        restoring the shelved cache.
+        (bidi_cache_ensure_space): Don't assume the required size is just
+        one BIDI_CACHE_CHUNK away.
+
+        * xdisp.c (back_to_previous_visible_line_start, reseat_1)
+        (init_iterator): Empty the bidi cache "stack".
+
 2011-07-03  Eli Zaretskii  <eliz@gnu.org>
 
         * bidi.c (bidi_shelve_cache, bidi_unshelve_cache): New functions.