From 6eec759623c7d77e01370c504543a29887c28034 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 2 Jul 2011 18:16:27 +0300
Subject: [PATCH] Start fixing cursor motion around invisible text. Hit a MAJOR
 design problem in pushing and popping bidi iterator state.

 src/xdisp.c (reseat_1): Call bidi_init_it to resync the bidi
 iterator with IT's position.
 (handle_stop, back_to_previous_visible_line_start, reseat_1):
 Reset the from_disp_prop_p flag.
 src/bidi.c (bidi_cache_search): Don't assume bidi_cache_last_idx is
 always valid if bidi_cache_idx is valid.
 (bidi_cache_find_level_change): xassert that bidi_cache_last_idx
 is valid if it's going to be used.
---
 src/ChangeLog | 10 ++++++++++
 src/bidi.c    |  6 +++++-
 src/xdisp.c   |  7 +++++--
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/ChangeLog b/src/ChangeLog
index c2da733feb1..1a443e848a7 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,15 @@
 2011-07-02  Eli Zaretskii  <eliz@gnu.org>
 
+	* xdisp.c (reseat_1): Call bidi_init_it to resync the bidi
+	iterator with IT's position.
+	(handle_stop, back_to_previous_visible_line_start, reseat_1):
+	Reset the from_disp_prop_p flag.
+
+	* bidi.c (bidi_cache_search): Don't assume bidi_cache_last_idx is
+	always valid if bidi_cache_idx is valid.
+	(bidi_cache_find_level_change): xassert that bidi_cache_last_idx
+	is valid if it's going to be used.
+
 	* dispextern.h (struct iterator_stack_entry, struct it): New
 	member from_disp_prop_p.
 
diff --git a/src/bidi.c b/src/bidi.c
index 87978058a5b..05c16a70f94 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -352,8 +352,10 @@ bidi_cache_search (EMACS_INT charpos, int level, int dir)
 {
   int i, i_start;
 
-  if (bidi_cache_idx)
+  if (bidi_cache_idx > bidi_cache_start)
     {
+      if (bidi_cache_last_idx == -1)
+	bidi_cache_last_idx = bidi_cache_idx - 1;
       if (charpos < bidi_cache[bidi_cache_last_idx].charpos)
 	{
 	  dir = -1;
@@ -418,6 +420,8 @@ bidi_cache_find_level_change (int level, int dir, int before)
       int i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1;
       int incr = before ? 1 : 0;
 
+      xassert (!dir || bidi_cache_last_idx >= 0);
+
       if (!dir)
 	dir = -1;
       else if (!incr)
diff --git a/src/xdisp.c b/src/xdisp.c
index 7c1b2051e57..c3d5fd9479b 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2915,6 +2915,7 @@ handle_stop (struct it *it)
 		{
 		  it->ignore_overlay_strings_at_pos_p = 1;
 		  it->string_from_display_prop_p = 0;
+		  it->from_disp_prop_p = 0;
 		  handle_overlay_change_p = 0;
 		}
 	      handled = HANDLED_RECOMPUTE_PROPS;
@@ -5542,6 +5543,7 @@ back_to_previous_visible_line_start (struct it *it)
 	--IT_BYTEPOS (it2);
 	it2.sp = 0;
 	it2.string_from_display_prop_p = 0;
+	it2.from_disp_prop_p = 0;
 	if (handle_display_prop (&it2) == HANDLED_RETURN
 	    && !NILP (val = get_char_property_and_overlay
 		      (make_number (pos), Qdisplay, Qnil, &overlay))
@@ -5740,12 +5742,13 @@ reseat_1 (struct it *it, struct text_pos pos, int set_stop_p)
   it->multibyte_p = !NILP (BVAR (current_buffer, enable_multibyte_characters));
   it->sp = 0;
   it->string_from_display_prop_p = 0;
+  it->from_disp_prop_p = 0;
   it->face_before_selective_p = 0;
   if (it->bidi_p)
     {
-      it->bidi_it.first_elt = 1;
+      bidi_init_it (IT_CHARPOS (*it), IT_BYTEPOS (*it), FRAME_WINDOW_P (it->f),
+		    &it->bidi_it);
       it->bidi_it.paragraph_dir = NEUTRAL_DIR;
-      it->bidi_it.disp_pos = -1;
       it->bidi_it.string.s = NULL;
       it->bidi_it.string.lstring = Qnil;
       it->bidi_it.string.bufpos = 0;
-- 
2.11.4.GIT