Fix a crash when visiting image files in bidi mode.

 xdisp.c (init_iterator): Don't turn on bidi reordering in unibyte buffers.
 See http://lists.gnu.org/archive/html/emacs-devel/2010-05/msg00263.html
 for the details.

2 files changed, 12 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c0e37f70c9c..018d4d1c418 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2010-05-10  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (init_iterator): Don't turn on bidi reordering in
+        unibyte buffers.  See
+        http://lists.gnu.org/archive/html/emacs-devel/2010-05/msg00263.html.
+
 2010-05-10  Glenn Morris  <rgm@gnu.org>
 
         * Makefile.in (LIBS_SYSTEM): Set using configure, not cpp.
diff --git a/src/xdisp.c b/src/xdisp.c
index 1e16180f7c9..92478b8e1f9 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2698,8 +2698,12 @@ init_iterator (it, w, charpos, bytepos, row, base_face_id)
   /* Are multibyte characters enabled in current_buffer?  */
   it->multibyte_p = !NILP (current_buffer->enable_multibyte_characters);
 
-  /* Do we need to reorder bidirectional text?  */
-  it->bidi_p = !NILP (current_buffer->bidi_display_reordering);
+  /* Do we need to reorder bidirectional text?  Not if this is a
+     unibyte buffer: all single-byte characters are by definition
+     strong L2R, so no reordering is needed.  And bidi.c doesn't
+     support unibyte buffers anyway.  */
+  it->bidi_p
+    = !NILP (current_buffer->bidi_display_reordering) && it->multibyte_p;
 
   /* Non-zero if we should highlight the region.  */
   highlight_region_p