From: Gregory Heytings <gregory@heytings.org>
Date: Thu, 4 Aug 2022 09:01:55 +0000 (+0000)
Subject: Improve Bidi with long lines.
X-Git-Tag: emacs-29.0.90~1447^2~431^2~3
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=82b602dc2f52775a4082d24d64380867da051350;p=emacs.git

Improve Bidi with long lines.

* src/composite.c (composition_compute_stop_pos): Use an 'endpos' that
is not too far away.
(find_automatic_composition): Use a 'head' that is not too far away.
Also make sure that this code path is not taken when long line
optimizations are disabled.

* src/dispextern.h (struct composition_it): Add a field that points
to the parent iterator.

* src/xdisp.c (init_iterator): Set it.
---

diff --git a/src/composite.c b/src/composite.c
index e721fe8c81f..9e641722cac 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -1021,7 +1021,11 @@ composition_compute_stop_pos (struct composition_it *cmp_it, ptrdiff_t charpos,
 	  /* But we don't know where to stop the searching.  */
 	  endpos = NILP (string) ? BEGV - 1 : -1;
 	  /* Usually we don't reach ENDPOS because we stop searching
-	     at an uncomposable character (NL, LRE, etc).  */
+	     at an uncomposable character (NL, LRE, etc).  In buffers
+	     with long lines, however, NL might be far away, so
+	     pretend that the buffer is smaller.  */
+	  if (current_buffer->long_line_optimizations_p)
+	    endpos = get_closer_narrowed_begv (cmp_it->parent_it->w, charpos);
 	}
     }
   cmp_it->id = -1;
@@ -1580,7 +1584,6 @@ find_automatic_composition (ptrdiff_t pos, ptrdiff_t limit, ptrdiff_t backlim,
   Lisp_Object window;
   struct window *w;
   bool need_adjustment = 0;
-  ptrdiff_t narrowed_begv;
 
   window = Fget_buffer_window (Fcurrent_buffer (), Qnil);
   if (NILP (window))
@@ -1597,11 +1600,14 @@ find_automatic_composition (ptrdiff_t pos, ptrdiff_t limit, ptrdiff_t backlim,
 	}
       else
 	head = backlim;
-      /* In buffers with very long lines, this function becomes very
-	 slow.  Pretend that the buffer is narrowed to make it fast.  */
-      narrowed_begv = get_narrowed_begv (w, window_point (w));
-      if (pos > narrowed_begv)
-	head = narrowed_begv;
+      if (current_buffer->long_line_optimizations_p)
+	{
+	  /* In buffers with very long lines, this function becomes very
+	     slow.  Pretend that the buffer is narrowed to make it fast.  */
+	  ptrdiff_t begv = get_closer_narrowed_begv (w, window_point (w));
+	  if (pos > begv)
+	    head = narrowed_begv;
+	}
       tail = ZV;
       stop = GPT;
       cur.pos_byte = CHAR_TO_BYTE (cur.pos);
diff --git a/src/dispextern.h b/src/dispextern.h
index 037e02ff58f..12ba927261f 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2287,6 +2287,8 @@ struct composition_it
      reverse order, and thus the grapheme clusters must be rendered
      from the last to the first.  */
   bool reversed_p;
+  /* Parent iterator. */
+  struct it *parent_it;
 
   /** The following members contain information about the current
       grapheme cluster.  */
diff --git a/src/xdisp.c b/src/xdisp.c
index 7d62c7823ed..12f56227e46 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3229,6 +3229,7 @@ init_iterator (struct it *it, struct window *w,
   it->f = XFRAME (w->frame);
 
   it->cmp_it.id = -1;
+  it->cmp_it.parent_it = it;
 
   if (max_redisplay_ticks > 0)
     update_redisplay_ticks (0, w);