Set up the bidi iterator for iterating display strings and overlay strings.

Not tested yet, just compiled.

 src/xdisp.c (handle_single_display_spec, next_overlay_string)
 (get_overlay_strings_1, push_display_prop): Set up the bidi
 iterator for displaying display or overlay strings.
 (forward_to_next_line_start): Don't use the shortcut if
 bidi-iterating.
 (back_to_previous_visible_line_start): If handle_display_prop
 pushed the iterator stack, restore the internal state of the bidi
 iterator by calling bidi_pop_it same number of times.
 (reseat_at_next_visible_line_start): If ON_NEWLINE_P is non-zero,
 and we are bidi-iterating, don't decrement the iterator position;
 instead, set the first_elt flag in the bidi iterator, to produce
 the same effect.
 (reseat_1): Remove redundant setting of string_from_display_prop_p.
 (push_display_prop): xassert that we are iterating a buffer.
 (push_it, pop_it): Save and restore the state of the
 bidi iterator.  Save and restore the bidi_p flag.
 (pop_it): Iterate out of display property for string iteration as
 well.
 (iterate_out_of_display_property): Support iteration over strings.
 (handle_single_display_spec): Set up it->bidi_it for iteration
 over a display string, and call bidi_init_it.
 src/bidi.c (bidi_cache_start_stack, bidi_push_it): Use IT_STACK_SIZE.
 src/dispextern.h (struct iterator_stack_entry): New member bidi_p.
 (struct it): Member bidi_p is now a bit field 1 bit wide.

1 files changed, 5 insertions, 6 deletions

diff --git a/src/bidi.c b/src/bidi.c
index b03e93df817..b518dd45782 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -548,11 +548,10 @@ bidi_peek_at_next_level (struct bidi_it *bidi_it)
 /***********************************************************************
              Pushing and popping the bidi iterator state
  ***********************************************************************/
-/* 10-slot stack for saving the start of the previous level of the
-   cache.  xdisp.c maintains a 5-slot cache for its iterator state,
-   and we need just a little bit more.  */
-#define CACHE_STACK_SIZE 10
-static int bidi_cache_start_stack[CACHE_STACK_SIZE];
+/* 5-slot stack for saving the start of the previous level of the
+   cache.  xdisp.c maintains a 5-slot stack for its iterator state,
+   and we need the same size of our stack.  */
+static int bidi_cache_start_stack[IT_STACK_SIZE];
 static int bidi_cache_sp;
 
 /* Push the bidi iterator state in preparation for reordering a
@@ -569,7 +568,7 @@ bidi_push_it (struct bidi_it *bidi_it)
   memcpy (&bidi_cache[bidi_cache_idx++], bidi_it, sizeof (struct bidi_it));
 
   /* Push the current cache start onto the stack.  */
-  if (bidi_cache_sp >= CACHE_STACK_SIZE)
+  if (bidi_cache_sp >= IT_STACK_SIZE)
     abort ();
   bidi_cache_start_stack[bidi_cache_sp++] = bidi_cache_start;