Finish and debug display of invisible text.

 xdisp.c (handle_invisible_prop): If we are `reseat'ed, init the
 paragraph direction and set the `reversed_p' flag in the IT's
 glyph row.  Fix exit conditions of the loop that skips invisible
 text.  Update IT->prev_stop after skipping invisible text.  Check
 for additional overlays at IT->stop_charpos, not at start_pos.

Clean up the mess with setting the glyph row reversed_p flag.
 dispnew.c (prepare_desired_row): Preserve the reversed_p flag.

 bidi.c (bidi_cache_find): Use bidi_copy_it instead of copying
 the whole struct (which includes uninitialized parts).
 (bidi_init_it): Don't initialize bidi_it->paragraph_dir.

 xdisp.c (display_line): Remove misplaced setting of
 row->reversed_p flags.  Copy the reversed_p flag to the next glyph
 row.
 (next_element_from_buffer): Check bidi_it.paragraph_dir rather
 than level_stack[0].level.  Reset the reversed_p flag for non-R2L
 paragraphs.

4 files changed, 89 insertions, 18 deletions

diff --git a/src/ChangeLog.bidi b/src/ChangeLog.bidi
index 40a858b0320..cbd1813cba2 100644
--- a/src/ChangeLog.bidi
+++ b/src/ChangeLog.bidi
@@ -1,3 +1,27 @@
+2010-01-25  Eli Zaretskii  <eliz@gnu.org>
+
+        Clean up the mess with setting the glyph row reversed_p flag.
+        * dispnew.c (prepare_desired_row): Preserve the reversed_p flag.
+
+        * bidi.c (bidi_cache_find): Use bidi_copy_it instead of copying
+        the whole struct (which includes uninitialized parts).
+        (bidi_init_it): Don't initialize bidi_it->paragraph_dir.
+
+        * xdisp.c (display_line): Remove misplaced setting of
+        row->reversed_p flags.  Copy the reversed_p flag to the next glyph
+        row.
+        (next_element_from_buffer): Check bidi_it.paragraph_dir rather
+        than level_stack[0].level.  Reset the reversed_p flag for non-R2L
+        paragraphs.
+
+        Fix display of invisible text.
+        * xdisp.c (handle_invisible_prop): If we are `reseat'ed, init the
+        paragraph direction and set the `reversed_p' flag in the IT's
+        glyph row.  Fix exit conditions of the loop that skips invisible
+        text.  Update IT->prev_stop after skipping invisible text.  Check
+        for additional overlays at IT->stop_charpos, not at start_pos.
+        (next_element_from_buffer):
+
 2010-01-16  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (handle_invisible_prop): Under bidi iteration, skip
diff --git a/src/bidi.c b/src/bidi.c
index 5abb4ca9f43..5c0169071ff 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -715,7 +715,7 @@ bidi_cache_find (int charpos, int level, struct bidi_it *bidi_it)
     {
       bidi_dir_t current_scan_dir = bidi_it->scan_dir;
 
-      *bidi_it = bidi_cache[i];
+      bidi_copy_it (bidi_it, &bidi_cache[i]);
       bidi_cache_last_idx = i;
       /* Don't let scan direction from from the cached state override
          the current scan direction.  */
@@ -971,7 +971,6 @@ bidi_init_it (EMACS_INT charpos, EMACS_INT bytepos, struct bidi_it *bidi_it)
   bidi_set_paragraph_end (bidi_it);
   bidi_it->new_paragraph = 1;
   bidi_it->separator_limit = -1;
-  bidi_it->paragraph_dir = NEUTRAL_DIR;
   bidi_it->type = NEUTRAL_B;
   bidi_it->type_after_w1 = UNKNOWN_BT;
   bidi_it->orig_type = UNKNOWN_BT;
diff --git a/src/dispnew.c b/src/dispnew.c
index 33c1fd89a40..897d38e48f0 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -1388,8 +1388,11 @@ prepare_desired_row (row)
 {
   if (!row->enabled_p)
     {
+      unsigned rp = row->reversed_p;
+
       clear_glyph_row (row);
       row->enabled_p = 1;
+      row->reversed_p = rp;
     }
 }
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 17a6f7eb4f0..703676127fa 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3789,7 +3789,7 @@ handle_invisible_prop (it)
 
       /* First of all, is there invisible text at this position?  */
       tem = start_charpos = IT_CHARPOS (*it);
-      pos = make_number (IT_CHARPOS (*it));
+      pos = make_number (tem);
       prop = get_char_property_and_overlay (pos, Qinvisible, it->window,
                                             &overlay);
       invis_p = TEXT_PROP_MEANS_INVISIBLE (prop);
@@ -3852,17 +3852,43 @@ handle_invisible_prop (it)
                  embedding level.  Therefore, we need to skip
                  invisible text using the bidi iterator, starting at
                  IT's current position, until we find ourselves
-                 outside the invisible text.  This avoids affecting
-                 the visual order of the displayed text when invisible
-                 properties are added or removed.  */
+                 outside the invisible text.  Skipping invisible text
+                 _after_ bidi iteration avoids affecting the visual
+                 order of the displayed text when invisible properties
+                 are added or removed.  */
+              if (it->bidi_it.first_elt)
+                {
+                  /* If we were `reseat'ed to a new paragraph,
+                     determine the paragraph base direction.  We need
+                     to do it now because next_element_from_buffer may
+                     not have a chance to do it, if we are going to
+                     skip any text at the beginning, which resets the
+                     FIRST_ELT flag.  */
+                  bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
+                  /* If the paragraph base direction is R2L, its
+                     glyphs should be reversed.  */
+                  if (it->glyph_row)
+                    {
+                      if (it->bidi_it.paragraph_dir == R2L)
+                        it->glyph_row->reversed_p = 1;
+                      else
+                        it->glyph_row->reversed_p = 0;
+                    }
+                }
               do
                 {
                   bidi_get_next_char_visually (&it->bidi_it);
                 }
-              while (start_charpos <= it->bidi_it.charpos
+              while (it->stop_charpos <= it->bidi_it.charpos
                      && it->bidi_it.charpos < newpos);
               IT_CHARPOS (*it) = it->bidi_it.charpos;
-              IT_BYTEPOS (*it) = CHAR_TO_BYTE (newpos);
+              IT_BYTEPOS (*it) = it->bidi_it.bytepos;
+              /* If we overstepped NEWPOS, record its position in the
+                 iterator, so that we skip invisible text if later the
+                 bidi iteration lands us in the invisible region
+                 again. */
+              if (IT_CHARPOS (*it) >= newpos)
+                it->prev_stop = newpos;
             }
           else
             {
@@ -3877,7 +3903,7 @@ handle_invisible_prop (it)
              overlay property instead of a text property, this is
              already handled in the overlay code.)  */
           if (NILP (overlay)
-              && get_overlay_strings (it, start_charpos))
+              && get_overlay_strings (it, it->stop_charpos))
             {
               handled = HANDLED_RECOMPUTE_PROPS;
               it->stack[it->sp - 1].display_ellipsis_p = display_ellipsis_p;
@@ -6200,7 +6226,16 @@ set_iterator_to_next (it, reseat_p)
               /* If this is a new paragraph, determine its base
                  direction (a.k.a. its base embedding level).  */
               if (it->bidi_it.new_paragraph)
-                bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
+                {
+                  bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
+                  if (it->glyph_row)
+                    {
+                      if (it->bidi_it.paragraph_dir == R2L)
+                        it->glyph_row->reversed_p = 1;
+                      else
+                        it->glyph_row->reversed_p = 0;
+                    }
+                }
               bidi_get_next_char_visually (&it->bidi_it);
               IT_BYTEPOS (*it) = it->bidi_it.bytepos;
               IT_CHARPOS (*it) = it->bidi_it.charpos;
@@ -6663,8 +6698,13 @@ next_element_from_buffer (it)
           bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
           /* If the paragraph base direction is R2L, its glyphs should
              be reversed.  */
-          if (it->glyph_row && (it->bidi_it.level_stack[0].level & 1) != 0)
-            it->glyph_row->reversed_p = 1;
+          if (it->glyph_row)
+            {
+              if (it->bidi_it.paragraph_dir == R2L)
+                it->glyph_row->reversed_p = 1;
+              else
+                it->glyph_row->reversed_p = 0;
+            }
           bidi_get_next_char_visually (&it->bidi_it);
         }
       else
@@ -6679,8 +6719,13 @@ next_element_from_buffer (it)
           it->bidi_it.charpos = IT_CHARPOS (*it);
           it->bidi_it.bytepos = IT_BYTEPOS (*it);
           bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it);
-          if (it->glyph_row && (it->bidi_it.level_stack[0].level & 1) != 0)
-            it->glyph_row->reversed_p = 1;
+          if (it->glyph_row)
+            {
+              if (it->bidi_it.paragraph_dir == R2L)
+                it->glyph_row->reversed_p = 1;
+              else
+                it->glyph_row->reversed_p = 0;
+            }
           do
             {
               /* Now return to buffer position where we were asked to
@@ -17028,10 +17073,6 @@ display_line (it)
   row->displays_text_p = 1;
   row->starts_in_middle_of_char_p = it->starts_in_middle_of_char_p;
   it->starts_in_middle_of_char_p = 0;
-  /* If the paragraph base direction is R2L, its glyphs should be
-     reversed.  */
-  if (it->bidi_p && (it->bidi_it.level_stack[0].level & 1) != 0)
-    row->reversed_p = 1;
 
   /* Arrange the overlays nicely for our purposes.  Usually, we call
      display_line on only one line at a time, in which case this
@@ -17566,6 +17607,10 @@ display_line (it)
   it->current_y += row->height;
   ++it->vpos;
   ++it->glyph_row;
+  /* The next row should use same value of the reversed_p flag as this
+     one.  set_iterator_to_next decides when it's a new paragraph and
+     recomputes the value of the flag accordingly.  */
+  it->glyph_row->reversed_p = row->reversed_p;
   it->start = row_end;
   return row->displays_text_p;
 }