Merge branch 'feature/fix-the-long-lines-display-bug'

1 files changed, 18 insertions, 8 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 4994a310438..a55af906e26 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -985,6 +985,7 @@ reset_buffer (register struct buffer *b)
   /* It is more conservative to start out "changed" than "unchanged".  */
   b->clip_changed = 0;
   b->prevent_redisplay_optimizations_p = 1;
+  b->long_line_optimizations_p = 0;
   bset_backed_up (b, Qnil);
   bset_local_minor_modes (b, Qnil);
   BUF_AUTOSAVE_MODIFF (b) = 0;
@@ -1501,7 +1502,7 @@ state of the current buffer.  Use with care.  */)
          decrease SAVE_MODIFF and auto_save_modified or increase
          MODIFF.  */
       if (SAVE_MODIFF >= MODIFF)
-        SAVE_MODIFF = modiff_incr (&MODIFF);
+        SAVE_MODIFF = modiff_incr (&MODIFF, 1);
       if (EQ (flag, Qautosaved))
         BUF_AUTOSAVE_MODIFF (b) = MODIFF;
     }
@@ -2446,6 +2447,7 @@ results, see Info node `(elisp)Swapping Text'.  */)
   swapfield (bidi_paragraph_cache, struct region_cache *);
   current_buffer->prevent_redisplay_optimizations_p = 1;
   other_buffer->prevent_redisplay_optimizations_p = 1;
+  swapfield (long_line_optimizations_p, bool_bf);
   swapfield (overlays_before, struct Lisp_Overlay *);
   swapfield (overlays_after, struct Lisp_Overlay *);
   swapfield (overlay_center, ptrdiff_t);
@@ -2465,12 +2467,12 @@ results, see Info node `(elisp)Swapping Text'.  */)
   bset_point_before_scroll (current_buffer, Qnil);
   bset_point_before_scroll (other_buffer, Qnil);
 
-  modiff_incr (&current_buffer->text->modiff);
-  modiff_incr (&other_buffer->text->modiff);
-  modiff_incr (&current_buffer->text->chars_modiff);
-  modiff_incr (&other_buffer->text->chars_modiff);
-  modiff_incr (&current_buffer->text->overlay_modiff);
-  modiff_incr (&other_buffer->text->overlay_modiff);
+  modiff_incr (&current_buffer->text->modiff, 1);
+  modiff_incr (&other_buffer->text->modiff, 1);
+  modiff_incr (&current_buffer->text->chars_modiff, 1);
+  modiff_incr (&other_buffer->text->chars_modiff, 1);
+  modiff_incr (&current_buffer->text->overlay_modiff, 1);
+  modiff_incr (&other_buffer->text->overlay_modiff, 1);
   current_buffer->text->beg_unchanged = current_buffer->text->gpt;
   current_buffer->text->end_unchanged = current_buffer->text->gpt;
   other_buffer->text->beg_unchanged = other_buffer->text->gpt;
@@ -4009,7 +4011,7 @@ modify_overlay (struct buffer *buf, ptrdiff_t start, ptrdiff_t end)
 
   bset_redisplay (buf);
 
-  modiff_incr (&BUF_OVERLAY_MODIFF (buf));
+  modiff_incr (&BUF_OVERLAY_MODIFF (buf), 1);
 }
 
 /* Remove OVERLAY from LIST.  */
@@ -6427,6 +6429,14 @@ Since `clone-indirect-buffer' calls `make-indirect-buffer', this hook
 will run for `clone-indirect-buffer' calls as well.  */);
   Vclone_indirect_buffer_hook = Qnil;
 
+  DEFVAR_LISP ("long-line-threshold", Vlong_line_threshold,
+               doc: /* Line length above which specific display optimizations are used.
+Display optimizations for long lines will automatically be enabled in
+buffers which contain one or more lines whose length is above that
+threshold.
+When nil, these display optimizations are disabled.  */);
+  XSETFASTINT (Vlong_line_threshold, 10000);
+
   defsubr (&Sbuffer_live_p);
   defsubr (&Sbuffer_list);
   defsubr (&Sget_buffer);