[rudalics@gmx.at: Re: jit lock sit-for provokes redisplay provokes imenu]

[Richard Stallman <rms@gnu.org>]

This is what we're thinking of using instead of
buffer-chars-modified-tick.  It is a smaller change and more modular;
presuming it solves the problem well enough, it is definitely
preferable for installation now.

So, what do people think of this change?

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Date: Sun, 27 Aug 2006 12:14:22 +0200
From: martin rudalics <rudalics@gmx.at>
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To:  rms@gnu.org
Subject: Re: jit lock sit-for provokes redisplay provokes imenu
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Sorry for procrastinating.  Is the attached patch acceptable?

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*** buffer.c.~1.506.~	Tue Aug 15 10:01:00 2006
- --- buffer.c	Sun Aug 27 11:41:52 2006
***************
*** 1148,1153 ****
- --- 1148,1187 ----

    return make_number (BUF_MODIFF (buf));
  }
+ 
+ DEFUN ("buffer-hash", Fbuffer_hash, Sbuffer_hash,
+        0, 1, 0,
+        doc: /* Return hash code for BUFFER.
+ No argument or nil as argument means use current buffer as BUFFER.  */)
+      (buffer)
+      register Lisp_Object buffer;
+ {
+   register struct buffer *buf;
+   register unsigned char *at, *to;
+   register unsigned int hash = 0;
+ 
+   if (NILP (buffer))
+     buf = current_buffer;
+   else
+     {
+       CHECK_BUFFER (buffer);
+       buf = XBUFFER (buffer);
+     }
+ 
+   at = BUF_BEG_ADDR (buf);
+   to = BUF_GPT_ADDR (buf);
+   while (at < to)
+     hash = ((((unsigned)(hash) << 4) + (((unsigned)(hash) >> 24) & 0x0fffffff))
+ 	    + (unsigned)(*at++));
+ 
+   at =  BUF_GAP_END_ADDR (buf);
+   to = BUF_Z_ADDR (buf);
+   while (at < to)
+     hash = ((((unsigned)(hash) << 4) + (((unsigned)(hash) >> 24) & 0x0fffffff))
+ 	    + (unsigned)(*at++));
+ 
+   return make_number (hash & INTMASK);
+ }
  \f
  DEFUN ("rename-buffer", Frename_buffer, Srename_buffer, 1, 2,
         "sRename buffer (to new name): \nP",
***************
*** 6024,6029 ****
- --- 6058,6064 ----
    defsubr (&Sbuffer_modified_p);
    defsubr (&Sset_buffer_modified_p);
    defsubr (&Sbuffer_modified_tick);
+   defsubr (&Sbuffer_hash);
    defsubr (&Srename_buffer);
    defsubr (&Sother_buffer);
    defsubr (&Sbuffer_enable_undo);


*** imenu.el.~1.118.~	Tue Aug 15 10:00:50 2006
- --- imenu.el	Sun Aug 27 11:32:36 2006
***************
*** 970,981 ****
    "The value of (buffer-modified-tick) as of last call to `imenu-update-menubar'.")
  (make-variable-buffer-local 'imenu-menubar-modified-tick)

  (defun imenu-update-menubar ()
    (when (and (current-local-map)
  	     (keymapp (lookup-key (current-local-map) [menu-bar index]))
! 	     (not (eq (buffer-modified-tick)
! 		      imenu-menubar-modified-tick)))
!     (setq imenu-menubar-modified-tick (buffer-modified-tick))
      (let ((index-alist (imenu--make-index-alist t)))
        ;; Don't bother updating if the index-alist has not changed
        ;; since the last time we did it.
- --- 970,988 ----
    "The value of (buffer-modified-tick) as of last call to `imenu-update-menubar'.")
  (make-variable-buffer-local 'imenu-menubar-modified-tick)

+ (defvar imenu-buffer-hash 0
+   "The value returned by `buffer-hash' as of last call to `imenu-update-menubar'.")
+ (make-variable-buffer-local 'imenu-buffer-hash)
+ 
  (defun imenu-update-menubar ()
    (when (and (current-local-map)
  	     (keymapp (lookup-key (current-local-map) [menu-bar index]))
! 	     (let ((tick (buffer-modified-tick)))
! 	       (when (/= tick imenu-menubar-modified-tick)
! 		 (setq imenu-menubar-modified-tick tick)))
! 	     (let ((hash (buffer-hash)))
! 	       (when (/= hash imenu-buffer-hash)
! 		 (setq imenu-buffer-hash hash))))
      (let ((index-alist (imenu--make-index-alist t)))
        ;; Don't bother updating if the index-alist has not changed
        ;; since the last time we did it.

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