Re: limit the number of log entries displayed by C-x v l

[Bob Rogers <rogers-emacs@rgrjr.dyndns.org>]

   From: Stefan Monnier <monnier@iro.umontreal.ca>
   Date: Sun, 22 Nov 2009 21:29:15 -0500

   >> They can't even do "log+diff", and some of the main contributors have
   >> already seen this suggestion back when I asked for it for Arch.
   >> Nobody's ever seemed to understand how useful it would be.

   > Bzr does have `log -p' (as does Git and Hg of course), which shows the
   > log and diff at the same time.

   Thanks for proving me wrong. ;-)
   So maybe there is hope for the feature of which I've been dreaming.

	   Stefan

Here's a non-backend-specific hack for C-n and C-p in vc-annotate-mode
that keeps any log-view-mode buffer displayed on the same frame in sync
to the same revision.  A post-command-hook solution might be more
thorough, though (handling C-s, e.g.), but is this in the direction of
what you had in mind?

					-- Bob Rogers
					   http://www.rgrjr.com/

------------------------------------------------------------------------
(defun vc-annotate-find-visible-log-buffer-window
       (file &optional start-window last-window)
  ;; Look for a window on the current frame that contains a
  ;; log-view-mode buffer that is looking at file.
  (or start-window (setq start-window (selected-window)
			 last-window start-window))
  (let ((window (next-window last-window)))
    (if (not (eq window start-window))
	;; See if window contains a log buffer.
	(or (save-excursion
	      (set-buffer (window-buffer window))
	      (and (eq major-mode 'log-view-mode)
		   (condition-case ()
		       ;; This shouldn't fail in a log-view-mode
		       ;; buffer, but just in case.
		       (equal (log-view-current-file) file)
		     (error nil))
		   window))
	    (vc-annotate-find-visible-log-buffer-window file start-window
							window)))))

(defun vc-annotate-next-line (&optional arg)
  "Next line in an annotation buffer, keeping any visible log in sync."
  (interactive "^p")
  (line-move-1 (or arg 1))
  (if (not (equal major-mode 'vc-annotate-mode))
      (error "Cannot be invoked outside of a vc annotate buffer."))
  (let* ((backend vc-annotate-backend)
	 (rev-at-line (vc-annotate-extract-revision-at-line))
	 (revision (car rev-at-line))
	 (file (cdr rev-at-line))
	 (log-buffer-window
	   (and rev-at-line
		(vc-annotate-find-visible-log-buffer-window file))))
    (if log-buffer-window
	(let ((original-window (selected-window)))
	  (select-window log-buffer-window)
	  (vc-call-backend backend 'show-log-entry revision)
	  (select-window original-window)))))

(defun vc-annotate-previous-line (&optional arg)
  "Previous line in an annotation buffer, keeping any visible log in sync."
  (interactive "^p")
  (vc-annotate-next-line (- (or arg 1))))

(define-key vc-annotate-mode-map "\C-n" 'vc-annotate-next-line)
(define-key vc-annotate-mode-map "\C-p" 'vc-annotate-previous-line)