3 files changed, 52 insertions, 14 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 4df4455e862..4d493eab7b1 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,15 @@
+2011-08-08  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (forward_to_next_line_start): Allow to use the
+        no-display-properties-and-no-overlays under bidi display.  Set
+        disp_pos in the bidi iterator to avoid searches for display
+        properties and overlays.
+
 2011-08-08  Chong Yidong  <cyd@stupidchicken.com>
 
+        * editfns.c (Fset_time_zone_rule): Document relationship with the
+        setenv function.
+
         * ftfont.c (ftfont_pattern_entity): Copy the extras argument to
         the font entity extracted from the cache (Bug#8109).
 
diff --git a/src/editfns.c b/src/editfns.c
index 5eed386afb7..297f7b6d7e4 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -2053,7 +2053,12 @@ static char *initial_tz;
 DEFUN ("set-time-zone-rule", Fset_time_zone_rule, Sset_time_zone_rule, 1, 1, 0,
        doc: /* Set the local time zone using TZ, a string specifying a time zone rule.
 If TZ is nil, use implementation-defined default time zone information.
-If TZ is t, use Universal Time.  */)
+If TZ is t, use Universal Time.
+
+Instead of calling this function, you typically want (setenv "TZ" TZ).
+That changes both the environment of the Emacs process and the
+variable `process-environment', whereas `set-time-zone-rule' affects
+only the former.  */)
   (Lisp_Object tz)
 {
   const char *tzstring;
diff --git a/src/xdisp.c b/src/xdisp.c
index d4f53012763..b09a1547a57 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -5567,19 +5567,42 @@ forward_to_next_line_start (struct it *it, int *skipped_p,
 
       xassert (!STRINGP (it->string));
 
-      /* If we are not bidi-reordering, and there isn't any `display'
-         property in sight, and no overlays, we can just use the
-         position of the newline in buffer text.  */
-      if (!it->bidi_p
-          && (it->stop_charpos >= limit
-              || ((pos = Fnext_single_property_change (make_number (start),
-                                                       Qdisplay, Qnil,
-                                                       make_number (limit)),
-                   NILP (pos))
-                  && next_overlay_change (start) == ZV)))
-        {
-          IT_CHARPOS (*it) = limit;
-          IT_BYTEPOS (*it) = CHAR_TO_BYTE (limit);
+      /* If there isn't any `display' property in sight, and no
+         overlays, we can just use the position of the newline in
+         buffer text.  */
+      if (it->stop_charpos >= limit
+          || ((pos = Fnext_single_property_change (make_number (start),
+                                                   Qdisplay, Qnil,
+                                                   make_number (limit)),
+               NILP (pos))
+              && next_overlay_change (start) == ZV))
+        {
+          if (!it->bidi_p)
+            {
+              IT_CHARPOS (*it) = limit;
+              IT_BYTEPOS (*it) = CHAR_TO_BYTE (limit);
+            }
+          else
+            {
+              struct bidi_it bprev;
+
+              /* Help bidi.c avoid expensive searches for display
+                 properties and overlays, by telling it that there are
+                 none up to `limit'.  */
+              if (it->bidi_it.disp_pos < limit)
+                {
+                  it->bidi_it.disp_pos = limit;
+                  it->bidi_it.disp_prop_p = 0;
+                }
+              do {
+                bprev = it->bidi_it;
+                bidi_move_to_visually_next (&it->bidi_it);
+              } while (it->bidi_it.charpos != limit);
+              IT_CHARPOS (*it) = limit;
+              IT_BYTEPOS (*it) = it->bidi_it.bytepos;
+              if (bidi_it_prev)
+                *bidi_it_prev = bprev;
+            }
           *skipped_p = newline_found_p = 1;
         }
       else