Fix bug #9212 with selective-display under bidi.

 src/xdisp.c (forward_to_next_line_start): Accept additional argument
 BIDI_IT_PREV, and store into it the state of the bidi iterator had
 on the newline.
 (reseat_at_next_visible_line_start): Use the bidi iterator state
 returned by forward_to_next_line_start to restore the state of
 it->bidi_it after backing up to previous newline.  (Bug#9212)

2 files changed, 41 insertions, 19 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 623ccc6f4be..4e8217cdf5f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2011-08-01  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (forward_to_next_line_start): Accept additional argument
+        BIDI_IT_PREV, and store into it the state of the bidi iterator had
+        on the newline.
+        (reseat_at_next_visible_line_start): Use the bidi iterator state
+        returned by forward_to_next_line_start to restore the state of
+        it->bidi_it after backing up to previous newline.  (Bug#9212)
+
 2011-07-30  Andreas Schwab  <schwab@linux-m68k.org>
 
         * regex.c (re_comp): Protoize.
diff --git a/src/xdisp.c b/src/xdisp.c
index 84c75bd91d9..a17d200c827 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -899,7 +899,7 @@ static void init_to_row_start (struct it *, struct window *,
 static int init_to_row_end (struct it *, struct window *,
                             struct glyph_row *);
 static void back_to_previous_line_start (struct it *);
-static int forward_to_next_line_start (struct it *, int *);
+static int forward_to_next_line_start (struct it *, int *, struct bidi_it *);
 static struct text_pos string_pos_nchars_ahead (struct text_pos,
                                                 Lisp_Object, EMACS_INT);
 static struct text_pos string_pos (EMACS_INT, Lisp_Object);
@@ -5494,6 +5494,9 @@ back_to_previous_line_start (struct it *it)
    continuously over the text).  Otherwise, don't change the value
    of *SKIPPED_P.
 
+   If BIDI_IT_PREV is non-NULL, store into it the state of the bidi
+   iterator on the newline, if it was found.
+
    Newlines may come from buffer text, overlay strings, or strings
    displayed via the `display' property.  That's the reason we can't
    simply use find_next_newline_no_quit.
@@ -5506,7 +5509,8 @@ back_to_previous_line_start (struct it *it)
    leads to wrong cursor motion.  */
 
 static int
-forward_to_next_line_start (struct it *it, int *skipped_p)
+forward_to_next_line_start (struct it *it, int *skipped_p,
+                            struct bidi_it *bidi_it_prev)
 {
   EMACS_INT old_selective;
   int newline_found_p, n;
@@ -5518,6 +5522,8 @@ forward_to_next_line_start (struct it *it, int *skipped_p)
       && it->c == '\n'
       && CHARPOS (it->position) == IT_CHARPOS (*it))
     {
+      if (it->bidi_p && bidi_it_prev)
+        *bidi_it_prev = it->bidi_it;
       set_iterator_to_next (it, 0);
       it->c = 0;
       return 1;
@@ -5539,6 +5545,8 @@ forward_to_next_line_start (struct it *it, int *skipped_p)
       if (!get_next_display_element (it))
         return 0;
       newline_found_p = it->what == IT_CHARACTER && it->c == '\n';
+      if (newline_found_p && it->bidi_p && bidi_it_prev)
+        *bidi_it_prev = it->bidi_it;
       set_iterator_to_next (it, 0);
     }
 
@@ -5573,6 +5581,8 @@ forward_to_next_line_start (struct it *it, int *skipped_p)
                  && !newline_found_p)
             {
               newline_found_p = ITERATOR_AT_END_OF_LINE_P (it);
+              if (newline_found_p && it->bidi_p && bidi_it_prev)
+                *bidi_it_prev = it->bidi_it;
               set_iterator_to_next (it, 0);
             }
         }
@@ -5696,8 +5706,9 @@ static void
 reseat_at_next_visible_line_start (struct it *it, int on_newline_p)
 {
   int newline_found_p, skipped_p = 0;
+  struct bidi_it bidi_it_prev;
 
-  newline_found_p = forward_to_next_line_start (it, &skipped_p);
+  newline_found_p = forward_to_next_line_start (it, &skipped_p, &bidi_it_prev);
 
   /* Skip over lines that are invisible because they are indented
      more than the value of IT->selective.  */
@@ -5708,7 +5719,8 @@ reseat_at_next_visible_line_start (struct it *it, int on_newline_p)
       {
         xassert (IT_BYTEPOS (*it) == BEGV
                  || FETCH_BYTE (IT_BYTEPOS (*it) - 1) == '\n');
-        newline_found_p = forward_to_next_line_start (it, &skipped_p);
+        newline_found_p =
+          forward_to_next_line_start (it, &skipped_p, &bidi_it_prev);
       }
 
   /* Position on the newline if that's what's requested.  */
@@ -5718,29 +5730,30 @@ reseat_at_next_visible_line_start (struct it *it, int on_newline_p)
         {
           if (IT_STRING_CHARPOS (*it) > 0)
             {
-              if (!it->bidi_p)
+              --IT_STRING_CHARPOS (*it);
+              --IT_STRING_BYTEPOS (*it);
+              if (it->bidi_p)
                 {
-                  --IT_STRING_CHARPOS (*it);
-                  --IT_STRING_BYTEPOS (*it);
+                  /* We need to restore the bidi iterator to the state
+                     it had on the newline.  */
+                  it->bidi_it = bidi_it_prev;
+                  xassert (IT_STRING_CHARPOS (*it) == it->bidi_it.charpos
+                           && IT_STRING_BYTEPOS (*it) == it->bidi_it.bytepos);
                 }
-              else
-                /* Setting this flag will cause
-                   bidi_move_to_visually_next not to advance, but
-                   instead deliver the current character (newline),
-                   which is what the ON_NEWLINE_P flag wants.  */
-                it->bidi_it.first_elt = 1;
             }
         }
       else if (IT_CHARPOS (*it) > BEGV)
         {
-          if (!it->bidi_p)
+          --IT_CHARPOS (*it);
+          --IT_BYTEPOS (*it);
+          if (it->bidi_p)
             {
-              --IT_CHARPOS (*it);
-              --IT_BYTEPOS (*it);
+              /* We need to restore the bidi iterator to the state it
+                 had on the newline.  */
+              it->bidi_it = bidi_it_prev;
+              xassert (IT_CHARPOS (*it) == it->bidi_it.charpos
+                       && IT_BYTEPOS (*it) == it->bidi_it.bytepos);
             }
-          /* With bidi iteration, the call to `reseat' will cause
-             bidi_move_to_visually_next deliver the current character,
-             the newline, instead of advancing.  */
           reseat (it, it->current.pos, 0);
         }
     }