+(defvar log-edit-parent-buffer nil)
+
+;;; Originally taken from VC-Log mode
+
+(defconst log-edit-maximum-comment-ring-size 32
+ "Maximum number of saved comments in the comment ring.")
+(defvar log-edit-comment-ring (make-ring log-edit-maximum-comment-ring-size))
+(defvar log-edit-comment-ring-index nil)
+(defvar log-edit-last-comment-match "")
+
+(defun log-edit-new-comment-index (stride len)
+ "Return the comment index STRIDE elements from the current one.
+LEN is the length of `log-edit-comment-ring'."
+ (mod (cond
+ (log-edit-comment-ring-index (+ log-edit-comment-ring-index stride))
+ ;; Initialize the index on the first use of this command
+ ;; so that the first M-p gets index 0, and the first M-n gets
+ ;; index -1.
+ ((> stride 0) (1- stride))
+ (t stride))
+ len))
+
+(defun log-edit-previous-comment (arg)
+ "Cycle backwards through comment history.
+With a numeric prefix ARG, go back ARG comments."
+ (interactive "*p")
+ (let ((len (ring-length log-edit-comment-ring)))
+ (if (<= len 0)
+ (progn (message "Empty comment ring") (ding))
+ ;; Don't use `erase-buffer' because we don't want to `widen'.
+ (delete-region (point-min) (point-max))
+ (setq log-edit-comment-ring-index (log-edit-new-comment-index arg len))
+ (message "Comment %d" (1+ log-edit-comment-ring-index))
+ (insert (ring-ref log-edit-comment-ring log-edit-comment-ring-index)))))
+
+(defun log-edit-next-comment (arg)
+ "Cycle forwards through comment history.
+With a numeric prefix ARG, go forward ARG comments."
+ (interactive "*p")
+ (log-edit-previous-comment (- arg)))
+
+(defun log-edit-comment-search-backward (str &optional stride)
+ "Search backwards through comment history for substring match of STR.
+If the optional argument STRIDE is present, that is a step-width to use
+when going through the comment ring."
+ ;; Why substring rather than regexp ? -sm
+ (interactive
+ (list (read-string "Comment substring: " nil nil log-edit-last-comment-match)))
+ (unless stride (setq stride 1))
+ (if (string= str "")
+ (setq str log-edit-last-comment-match)
+ (setq log-edit-last-comment-match str))
+ (let* ((str (regexp-quote str))
+ (len (ring-length log-edit-comment-ring))
+ (n (log-edit-new-comment-index stride len)))
+ (while (progn (when (or (>= n len) (< n 0)) (error "Not found"))
+ (not (string-match str (ring-ref log-edit-comment-ring n))))
+ (setq n (+ n stride)))
+ (setq log-edit-comment-ring-index n)
+ (log-edit-previous-comment 0)))
+
+(defun log-edit-comment-search-forward (str)
+ "Search forwards through comment history for a substring match of STR."
+ (interactive
+ (list (read-string "Comment substring: " nil nil log-edit-last-comment-match)))
+ (log-edit-comment-search-backward str -1))
+
+(defun log-edit-comment-to-change-log (&optional whoami file-name)
+ "Enter last VC comment into the change log for the current file.
+WHOAMI (interactive prefix) non-nil means prompt for user name
+and site. FILE-NAME is the name of the change log; if nil, use
+`change-log-default-name'.
+
+This may be useful as a `log-edit-checkin-hook' to update change logs
+automatically."
+ (interactive (if current-prefix-arg
+ (list current-prefix-arg
+ (prompt-for-change-log-name))))
+ (let (;; Extract the comment first so we get any error before doing anything.
+ (comment (ring-ref log-edit-comment-ring 0))
+ ;; Don't let add-change-log-entry insert a defun name.
+ (add-log-current-defun-function 'ignore)
+ end)
+ ;; Call add-log to do half the work.
+ (add-change-log-entry whoami file-name t t)
+ ;; Insert the VC comment, leaving point before it.
+ (setq end (save-excursion (insert comment) (point-marker)))
+ (if (looking-at "\\s *\\s(")
+ ;; It starts with an open-paren, as in "(foo): Frobbed."
+ ;; So remove the ": " add-log inserted.
+ (delete-char -2))
+ ;; Canonicalize the white space between the file name and comment.
+ (just-one-space)
+ ;; Indent rest of the text the same way add-log indented the first line.
+ (let ((indentation (current-indentation)))
+ (save-excursion
+ (while (< (point) end)
+ (forward-line 1)
+ (indent-to indentation))
+ (setq end (point))))
+ ;; Fill the inserted text, preserving open-parens at bol.
+ (let ((paragraph-start (concat paragraph-start "\\|\\s *\\s(")))
+ (beginning-of-line)
+ (fill-region (point) end))
+ ;; Canonicalize the white space at the end of the entry so it is
+ ;; separated from the next entry by a single blank line.
+ (skip-syntax-forward " " end)
+ (delete-char (- (skip-syntax-backward " ")))
+ (or (eobp) (looking-at "\n\n")
+ (insert "\n"))))
+
+;; Compatibility with old names.
+(define-obsolete-variable-alias 'vc-comment-ring 'log-edit-comment-ring "22.1")
+(define-obsolete-variable-alias 'vc-comment-ring-index 'log-edit-comment-ring-index "22.1")
+(define-obsolete-function-alias 'vc-previous-comment 'log-edit-previous-comment "22.1")
+(define-obsolete-function-alias 'vc-next-comment 'log-edit-next-comment "22.1")
+(define-obsolete-function-alias 'vc-comment-search-reverse 'log-edit-comment-search-backward "22.1")
+(define-obsolete-function-alias 'vc-comment-search-forward 'log-edit-comment-search-forward "22.1")
+(define-obsolete-function-alias 'vc-comment-to-change-log 'log-edit-comment-to-change-log "22.1")
+
+;;;
+;;; Actual code
+;;;
+
+(defvar log-edit-font-lock-keywords
+ '(("\\`\\(Summary:\\)\\(.*\\)"
+ (1 font-lock-keyword-face)
+ (2 font-lock-function-name-face))))