Don't use hook pre-redisplay-functions. Set buffer-local tab-line-format.

* lisp/tab-line.el (tab-line-format): Move to C.
(tab-line-update-window-parameter): Remove function.
(global-tab-line-mode): Set the default value of tab-line-format.

* src/buffer.c (syms_of_buffer): Define buffer-local variable
tab-line-format.

* src/buffer.h (struct buffer): Add tab_line_format_.

* src/window.c (window_wants_tab_line):
* src/xdisp.c (pos_visible_p, display_mode_lines):
Check for buffer-local tab_line_format.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/buffer.h b/src/buffer.h
index 2080a6f40b7..e411ab5461d 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -539,6 +539,10 @@ struct buffer
      of windows.  Nil means don't display that line.  */
   Lisp_Object header_line_format_;
 
+  /* Analogous to mode_line_format for the line displayed at the top
+     of windows.  Nil means don't display that line.  */
+  Lisp_Object tab_line_format_;
+
   /* Keys that are bound local to this buffer.  */
   Lisp_Object keymap_;