From Ulf Jasper <ulf.jasper@web.de>:

[emacs.git] / lisp / add-log.el

;;; add-log.el --- change log maintenance commands for Emacs

;; Copyright (C) 1985, 86, 88, 93, 94, 97, 98, 2000, 03, 2004
;;           Free Software Foundation, Inc.

;; Maintainer: FSF
;; Keywords: tools

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; This facility is documented in the Emacs Manual.

;;; Code:

(eval-when-compile
  (require 'timezone))

(defgroup change-log nil
  "Change log maintenance"
  :group 'tools
  :link '(custom-manual "(emacs)Change Log")
  :prefix "change-log-"
  :prefix "add-log-")


(defcustom change-log-default-name nil
  "*Name of a change log file for \\[add-change-log-entry]."
  :type '(choice (const :tag "default" nil)
                 string)
  :group 'change-log)

(defcustom change-log-mode-hook nil
  "Normal hook run by `change-log-mode'."
  :type 'hook
  :group 'change-log)

;; Many modes set this variable, so avoid warnings.
;;;###autoload
(defcustom add-log-current-defun-function nil
  "*If non-nil, function to guess name of surrounding function.
It is used by `add-log-current-defun' in preference to built-in rules.
Returns function's name as a string, or nil if outside a function."
  :type '(choice (const nil) function)
  :group 'change-log)

;;;###autoload
(defcustom add-log-full-name nil
  "*Full name of user, for inclusion in ChangeLog daily headers.
This defaults to the value returned by the function `user-full-name'."
  :type '(choice (const :tag "Default" nil)
                 string)
  :group 'change-log)

;;;###autoload
(defcustom add-log-mailing-address nil
  "*Electronic mail addresses of user, for inclusion in ChangeLog headers.
This defaults to the value of `user-mail-address'.  In addition to
being a simple string, this value can also be a list.  All elements
will be recognized as referring to the same user; when creating a new
ChangeLog entry, one element will be chosen at random."
  :type '(choice (const :tag "Default" nil)
                 (string :tag "String")
                 (repeat :tag "List of Strings" string))
  :group 'change-log)

(defcustom add-log-time-format 'add-log-iso8601-time-string
  "*Function that defines the time format.
For example, `add-log-iso8601-time-string', which gives the
date in international ISO 8601 format,
and `current-time-string' are two valid values."
  :type '(radio (const :tag "International ISO 8601 format"
                       add-log-iso8601-time-string)
                (const :tag "Old format, as returned by `current-time-string'"
                       current-time-string)
                (function :tag "Other"))
  :group 'change-log)

(defcustom add-log-keep-changes-together nil
  "*If non-nil, normally keep day's log entries for one file together.

Log entries for a given file made with \\[add-change-log-entry] or
\\[add-change-log-entry-other-window] will only be added to others \
for that file made
today if this variable is non-nil or that file comes first in today's
entries.  Otherwise another entry for that file will be started.  An
original log:

        * foo (...): ...
        * bar (...): change 1

in the latter case, \\[add-change-log-entry-other-window] in a \
buffer visiting `bar', yields:

        * bar (...): -!-
        * foo (...): ...
        * bar (...): change 1

and in the former:

        * foo (...): ...
        * bar (...): change 1
        (...): -!-

The NEW-ENTRY arg to `add-change-log-entry' can override the effect of
this variable."
  :version "20.3"
  :type 'boolean
  :group 'change-log)

(defcustom add-log-always-start-new-record nil
  "*If non-nil, `add-change-log-entry' will always start a new record."
  :version "22.1"
  :type 'boolean
  :group 'change-log)

(defcustom add-log-buffer-file-name-function nil
  "*If non-nil, function to call to identify the full filename of a buffer.
This function is called with no argument.  If this is nil, the default is to
use `buffer-file-name'."
  :type '(choice (const nil) function)
  :group 'change-log)

(defcustom add-log-file-name-function nil
  "*If non-nil, function to call to identify the filename for a ChangeLog entry.
This function is called with one argument, the value of variable
`buffer-file-name' in that buffer.  If this is nil, the default is to
use the file's name relative to the directory of the change log file."
  :type '(choice (const nil) function)
  :group 'change-log)


(defcustom change-log-version-info-enabled nil
  "*If non-nil, enable recording version numbers with the changes."
  :version "21.1"
  :type 'boolean
  :group 'change-log)

(defcustom change-log-version-number-regexp-list
  (let ((re    "\\([0-9]+\.[0-9.]+\\)"))
    (list
     ;;  (defconst ad-version "2.15"
     (concat "^(def[^ \t\n]+[ \t]+[^ \t\n][ \t]\"" re)
     ;; Revision: pcl-cvs.el,v 1.72 1999/09/05 20:21:54 monnier Exp
     (concat "^;+ *Revision: +[^ \t\n]+[ \t]+" re)))
  "*List of regexps to search for version number.
The version number must be in group 1.
Note: The search is conducted only within 10%, at the beginning of the file."
  :version "21.1"
  :type '(repeat regexp)
  :group 'change-log)

(defface change-log-date-face
  '((t (:inherit font-lock-string-face)))
  "Face used to highlight dates in date lines."
  :version "21.1"
  :group 'change-log)

(defface change-log-name-face
  '((t (:inherit font-lock-constant-face)))
  "Face for highlighting author names."
  :version "21.1"
  :group 'change-log)

(defface change-log-email-face
  '((t (:inherit font-lock-variable-name-face)))
  "Face for highlighting author email addresses."
  :version "21.1"
  :group 'change-log)

(defface change-log-file-face
  '((t (:inherit font-lock-function-name-face)))
  "Face for highlighting file names."
  :version "21.1"
  :group 'change-log)

(defface change-log-list-face
  '((t (:inherit font-lock-keyword-face)))
  "Face for highlighting parenthesized lists of functions or variables."
  :version "21.1"
  :group 'change-log)

(defface change-log-conditionals-face
  '((t (:inherit font-lock-variable-name-face)))
  "Face for highlighting conditionals of the form `[...]'."
  :version "21.1"
  :group 'change-log)

(defface change-log-function-face
  '((t (:inherit font-lock-variable-name-face)))
  "Face for highlighting items of the form `<....>'."
  :version "21.1"
  :group 'change-log)

(defface change-log-acknowledgement-face
  '((t (:inherit font-lock-comment-face)))
  "Face for highlighting acknowledgments."
  :version "21.1"
  :group 'change-log)

(defvar change-log-font-lock-keywords
  '(;;
    ;; Date lines, new and old styles.
    ("^\\sw.........[0-9:+ ]*"
     (0 'change-log-date-face)
     ;; Name and e-mail; some people put e-mail in parens, not angles.
     ("\\([^<(]+?\\)[ \t]*[(<]\\([A-Za-z0-9_.-]+@[A-Za-z0-9_.-]+\\)[>)]" nil nil
      (1 'change-log-name-face)
      (2 'change-log-email-face)))
    ;;
    ;; File names.
    ("^\t\\* \\([^ ,:([\n]+\\)"
     (1 'change-log-file-face)
     ;; Possibly further names in a list:
     ("\\=, \\([^ ,:([\n]+\\)" nil nil (1 'change-log-file-face))
     ;; Possibly a parenthesized list of names:
     ("\\= (\\([^() ,\n]+\\|(\\(setf\\|SETF\\) [^() ,\n]+)\\)"
      nil nil (1 'change-log-list-face))
     ("\\=, *\\([^() ,\n]+\\|(\\(setf\\|SETF\\) [^() ,\n]+)\\)"
      nil nil (1 'change-log-list-face)))
    ;;
    ;; Function or variable names.
    ("^\t(\\([^() ,\n]+\\|(\\(setf\\|SETF\\) [^() ,\n]+)\\)"
     (1 'change-log-list-face)
     ("\\=, *\\([^() ,\n]+\\|(\\(setf\\|SETF\\) [^() ,\n]+)\\)" nil nil
      (1 'change-log-list-face)))
    ;;
    ;; Conditionals.
    ("\\[!?\\([^]\n]+\\)\\]\\(:\\| (\\)" (1 'change-log-conditionals-face))
    ;;
    ;; Function of change.
    ("<\\([^>\n]+\\)>\\(:\\| (\\)" (1 'change-log-function-face))
    ;;
    ;; Acknowledgements.
    ;; Don't include plain "From" because that is vague;
    ;; we want to encourage people to say something more specific.
    ("\\(^\t\\|  \\)\\(Patch\\(es\\)? by\\|Report\\(ed by\\| from\\)\\|Suggest\\(ed by\\|ion from\\)\\)"
     2 'change-log-acknowledgement-face))
  "Additional expressions to highlight in Change Log mode.")

(defvar change-log-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map [?\C-c ?\C-p] 'add-log-edit-prev-comment)
    (define-key map [?\C-c ?\C-n] 'add-log-edit-next-comment)
    map)
  "Keymap for Change Log major mode.")

(defvar change-log-time-zone-rule nil
  "Time zone used for calculating change log time stamps.
It takes the same format as the TZ argument of `set-time-zone-rule'.
If nil, use local time.")

(defun add-log-iso8601-time-zone (time)
  (let* ((utc-offset (or (car (current-time-zone time)) 0))
         (sign (if (< utc-offset 0) ?- ?+))
         (sec (abs utc-offset))
         (ss (% sec 60))
         (min (/ sec 60))
         (mm (% min 60))
         (hh (/ min 60)))
    (format (cond ((not (zerop ss)) "%c%02d:%02d:%02d")
                  ((not (zerop mm)) "%c%02d:%02d")
                  (t "%c%02d"))
            sign hh mm ss)))

(defun add-log-iso8601-time-string ()
  (if change-log-time-zone-rule
      (let ((tz (getenv "TZ"))
            (now (current-time)))
        (unwind-protect
            (progn
              (set-time-zone-rule change-log-time-zone-rule)
              (concat
               (format-time-string "%Y-%m-%d " now)
               (add-log-iso8601-time-zone now)))
          (set-time-zone-rule tz)))
    (format-time-string "%Y-%m-%d")))

(defun change-log-name ()
  "Return (system-dependent) default name for a change log file."
  (or change-log-default-name
      (if (eq system-type 'vax-vms)
          "$CHANGE_LOG$.TXT"
        "ChangeLog")))

(defun add-log-edit-prev-comment (arg)
  "Cycle backward through Log-Edit mode comment history.
With a numeric prefix ARG, go back ARG comments."
  (interactive "*p")
  (save-restriction
    (narrow-to-region (point)
                      (if (memq last-command '(add-log-edit-prev-comment
                                               add-log-edit-next-comment))
                          (mark) (point)))
    (when (fboundp 'log-edit-previous-comment)
      (log-edit-previous-comment arg)
      (indent-region (point-min) (point-max))
      (goto-char (point-min))
      (unless (save-restriction (widen) (bolp))
        (delete-region (point) (progn (skip-chars-forward " \t\n") (point))))
      (set-mark (point-min))
      (goto-char (point-max))
      (delete-region (point) (progn (skip-chars-backward " \t\n") (point))))))

(defun add-log-edit-next-comment (arg)
  "Cycle forward through Log-Edit mode comment history.
With a numeric prefix ARG, go back ARG comments."
  (interactive "*p")
  (add-log-edit-prev-comment (- arg)))

;;;###autoload
(defun prompt-for-change-log-name ()
  "Prompt for a change log name."
  (let* ((default (change-log-name))
         (name (expand-file-name
                (read-file-name (format "Log file (default %s): " default)
                                nil default))))
    ;; Handle something that is syntactically a directory name.
    ;; Look for ChangeLog or whatever in that directory.
    (if (string= (file-name-nondirectory name) "")
        (expand-file-name (file-name-nondirectory default)
                          name)
      ;; Handle specifying a file that is a directory.
      (if (file-directory-p name)
          (expand-file-name (file-name-nondirectory default)
                            (file-name-as-directory name))
        name))))

(defun change-log-version-number-search ()
  "Return version number of current buffer's file.
This is the value returned by `vc-workfile-version' or, if that is
nil, by matching `change-log-version-number-regexp-list'."
  (let* ((size (buffer-size))
         (limit
          ;; The version number can be anywhere in the file, but
          ;; restrict search to the file beginning: 10% should be
          ;; enough to prevent some mishits.
          ;;
          ;; Apply percentage only if buffer size is bigger than
          ;; approx 100 lines.
          (if (> size (* 100 80)) (+ (point) (/ size 10)))))
    (or (and buffer-file-name (vc-workfile-version buffer-file-name))
        (save-restriction
          (widen)
          (let ((regexps change-log-version-number-regexp-list)
                version)
            (while regexps
              (save-excursion
                (goto-char (point-min))
                (when (re-search-forward (pop regexps) limit t)
                  (setq version (match-string 1)
                        regexps nil))))
            version)))))


;;;###autoload
(defun find-change-log (&optional file-name buffer-file)
  "Find a change log file for \\[add-change-log-entry] and return the name.

Optional arg FILE-NAME specifies the file to use.
If FILE-NAME is nil, use the value of `change-log-default-name'.
If 'change-log-default-name' is nil, behave as though it were 'ChangeLog'
\(or whatever we use on this operating system).

If 'change-log-default-name' contains a leading directory component, then
simply find it in the current directory.  Otherwise, search in the current
directory and its successive parents for a file so named.

Once a file is found, `change-log-default-name' is set locally in the
current buffer to the complete file name.
Optional arg BUFFER-FILE overrides `buffer-file-name'."
  ;; If user specified a file name or if this buffer knows which one to use,
  ;; just use that.
  (or file-name
      (setq file-name (and change-log-default-name
                           (file-name-directory change-log-default-name)
                           change-log-default-name))
      (progn
        ;; Chase links in the source file
        ;; and use the change log in the dir where it points.
        (setq file-name (or (and (or buffer-file buffer-file-name)
                                 (file-name-directory
                                  (file-chase-links
                                   (or buffer-file buffer-file-name))))
                            default-directory))
        (if (file-directory-p file-name)
            (setq file-name (expand-file-name (change-log-name) file-name)))
        ;; Chase links before visiting the file.
        ;; This makes it easier to use a single change log file
        ;; for several related directories.
        (setq file-name (file-chase-links file-name))
        (setq file-name (expand-file-name file-name))
        ;; Move up in the dir hierarchy till we find a change log file.
        (let ((file1 file-name)
              parent-dir)
          (while (and (not (or (get-file-buffer file1) (file-exists-p file1)))
                      (progn (setq parent-dir
                                   (file-name-directory
                                    (directory-file-name
                                     (file-name-directory file1))))
                             ;; Give up if we are already at the root dir.
                             (not (string= (file-name-directory file1)
                                           parent-dir))))
            ;; Move up to the parent dir and try again.
            (setq file1 (expand-file-name
                         (file-name-nondirectory (change-log-name))
                         parent-dir)))
          ;; If we found a change log in a parent, use that.
          (if (or (get-file-buffer file1) (file-exists-p file1))
              (setq file-name file1)))))
  ;; Make a local variable in this buffer so we needn't search again.
  (set (make-local-variable 'change-log-default-name) file-name)
  file-name)

(defun add-log-file-name (buffer-file log-file)
  ;; Never want to add a change log entry for the ChangeLog file itself.
  (unless (or (null buffer-file) (string= buffer-file log-file))
    (if add-log-file-name-function
        (funcall add-log-file-name-function buffer-file)
      (setq buffer-file
            (if (string-match
                 (concat "^" (regexp-quote (file-name-directory log-file)))
                 buffer-file)
                (substring buffer-file (match-end 0))
              (file-name-nondirectory buffer-file)))
      ;; If we have a backup file, it's presumably because we're
      ;; comparing old and new versions (e.g. for deleted
      ;; functions) and we'll want to use the original name.
      (if (backup-file-name-p buffer-file)
          (file-name-sans-versions buffer-file)
        buffer-file))))

;;;###autoload
(defun add-change-log-entry (&optional whoami file-name other-window new-entry)
  "Find change log file, and add an entry for today and an item for this file.
Optional arg WHOAMI (interactive prefix) non-nil means prompt for user
name and email (stored in `add-log-full-name' and `add-log-mailing-address').

Second arg FILE-NAME is file name of the change log.
If nil, use the value of `change-log-default-name'.

Third arg OTHER-WINDOW non-nil means visit in other window.

Fourth arg NEW-ENTRY non-nil means always create a new entry at the front;
never append to an existing entry.  Option `add-log-keep-changes-together'
otherwise affects whether a new entry is created.

Option `add-log-always-start-new-record' non-nil means always create a
new record, even when the last record was made on the same date and by
the same person.

The change log file can start with a copyright notice and a copying
permission notice.  The first blank line indicates the end of these
notices.

Today's date is calculated according to `change-log-time-zone-rule' if
non-nil, otherwise in local time."
  (interactive (list current-prefix-arg
                     (prompt-for-change-log-name)))
  (let* ((defun (add-log-current-defun))
         (version (and change-log-version-info-enabled
                       (change-log-version-number-search)))
         (buf-file-name (if add-log-buffer-file-name-function
                            (funcall add-log-buffer-file-name-function)
                          buffer-file-name))
         (buffer-file (if buf-file-name (expand-file-name buf-file-name)))
         (file-name (expand-file-name (find-change-log file-name buffer-file)))
         ;; Set ITEM to the file name to use in the new item.
         (item (add-log-file-name buffer-file file-name))
         bound
         (full-name (or add-log-full-name (user-full-name)))
         (mailing-address (or add-log-mailing-address user-mail-address)))

    (if whoami
        (progn
          (setq full-name (read-input "Full name: " full-name))
          ;; Note that some sites have room and phone number fields in
          ;; full name which look silly when inserted.  Rather than do
          ;; anything about that here, let user give prefix argument so that
          ;; s/he can edit the full name field in prompter if s/he wants.
          (setq mailing-address
                (read-input "Mailing address: " mailing-address))))

    (unless (equal file-name buffer-file-name)
      (if (or other-window (window-dedicated-p (selected-window)))
          (find-file-other-window file-name)
        (find-file file-name)))
    (or (eq major-mode 'change-log-mode)
        (change-log-mode))
    (undo-boundary)
    (goto-char (point-min))

    ;; If file starts with a copyright and permission notice, skip them.
    ;; Assume they end at first blank line.
    (when (looking-at "Copyright")
      (search-forward "\n\n")
      (skip-chars-forward "\n"))

    ;; Advance into first entry if it is usable; else make new one.
    (let ((new-entries (mapcar (lambda (addr)
                                 (concat (funcall add-log-time-format)
                                         "  " full-name
                                         "  <" addr ">"))
                               (if (consp mailing-address)
                                   mailing-address
                                 (list mailing-address)))))
      (if (and (not add-log-always-start-new-record)
               (let ((hit nil))
                 (dolist (entry new-entries hit)
                   (when (looking-at (regexp-quote entry))
                     (setq hit t)))))
          (forward-line 1)
        (insert (nth (random (length new-entries))
                     new-entries)
                "\n\n")
        (forward-line -1)))

    ;; Determine where we should stop searching for a usable
    ;; item to add to, within this entry.
    (setq bound
          (save-excursion
            (if (looking-at "\n*[^\n* \t]")
                (skip-chars-forward "\n")
              (if add-log-keep-changes-together
                  (forward-page)        ; page delimits entries for date
                (forward-paragraph)))   ; paragraph delimits entries for file
            (point)))

    ;; Now insert the new line for this item.
    (cond ((re-search-forward "^\\s *\\*\\s *$" bound t)
           ;; Put this file name into the existing empty item.
           (if item
               (insert item)))
          ((and (not new-entry)
                (let (case-fold-search)
                  (re-search-forward
                   (concat (regexp-quote (concat "* " item))
                           ;; Don't accept `foo.bar' when
                           ;; looking for `foo':
                           "\\(\\s \\|[(),:]\\)")
                   bound t)))
           ;; Add to the existing item for the same file.
           (re-search-forward "^\\s *$\\|^\\s \\*")
           (goto-char (match-beginning 0))
           ;; Delete excess empty lines; make just 2.
           (while (and (not (eobp)) (looking-at "^\\s *$"))
             (delete-region (point) (line-beginning-position 2)))
           (insert-char ?\n 2)
           (forward-line -2)
           (indent-relative-maybe))
          (t
           ;; Make a new item.
           (while (looking-at "\\sW")
             (forward-line 1))
           (while (and (not (eobp)) (looking-at "^\\s *$"))
             (delete-region (point) (line-beginning-position 2)))
           (insert-char ?\n 3)
           (forward-line -2)
           (indent-to left-margin)
           (insert "* ")
           (if item (insert item))))
    ;; Now insert the function name, if we have one.
    ;; Point is at the item for this file,
    ;; either at the end of the line or at the first blank line.
    (if (not defun)
        ;; No function name, so put in a colon unless we have just a star.
        (unless (save-excursion
                  (beginning-of-line 1)
                  (looking-at "\\s *\\(\\*\\s *\\)?$"))
          (insert ": ")
          (if version (insert version ?\ )))
      ;; Make it easy to get rid of the function name.
      (undo-boundary)
      (unless (save-excursion
                (beginning-of-line 1)
                (looking-at "\\s *$"))
        (insert ?\ ))
      ;; See if the prev function name has a message yet or not.
      ;; If not, merge the two items.
      (let ((pos (point-marker)))
        (skip-syntax-backward " ")
        (skip-chars-backward "):")
        (if (and (looking-at "):")
                 (let ((pos (save-excursion (backward-sexp 1) (point))))
                   (when (equal (buffer-substring pos (point)) defun)
                     (delete-region pos (point)))
                   (> fill-column (+ (current-column) (length defun) 4))))
            (progn (skip-chars-backward ", ")
                   (delete-region (point) pos)
                   (unless (memq (char-before) '(?\()) (insert ", ")))
          (if (looking-at "):")
              (delete-region (+ 1 (point)) (line-end-position)))
          (goto-char pos)
          (insert "("))
        (set-marker pos nil))
      (insert defun "): ")
      (if version (insert version ?\ )))))

;;;###autoload
(defun add-change-log-entry-other-window (&optional whoami file-name)
  "Find change log file in other window and add entry and item.
This is just like `add-change-log-entry' except that it displays
the change log file in another window."
  (interactive (if current-prefix-arg
                   (list current-prefix-arg
                         (prompt-for-change-log-name))))
  (add-change-log-entry whoami file-name t))
;;;###autoload (define-key ctl-x-4-map "a" 'add-change-log-entry-other-window)

(defvar add-log-indent-text 0)

(defun add-log-indent ()
  (let* ((indent
          (save-excursion
            (beginning-of-line)
            (skip-chars-forward " \t")
            (cond
             ((and (looking-at "\\(.*\\)  [^ \n].*[^ \n]  <.*>$")
                   ;; Matching the output of add-log-time-format is difficult,
                   ;; but I'll get it has at least two adjacent digits.
                   (string-match "[[:digit:]][[:digit:]]" (match-string 1)))
              0)
             ((looking-at "[^*(]")
              (+ (current-left-margin) add-log-indent-text))
             (t (current-left-margin)))))
         (pos (save-excursion (indent-line-to indent) (point))))
    (if (> pos (point)) (goto-char pos))))


(defvar smerge-resolve-function)

;;;###autoload
(define-derived-mode change-log-mode text-mode "Change Log"
  "Major mode for editing change logs; like Indented Text Mode.
Prevents numeric backups and sets `left-margin' to 8 and `fill-column' to 74.
New log entries are usually made with \\[add-change-log-entry] or \\[add-change-log-entry-other-window].
Each entry behaves as a paragraph, and the entries for one day as a page.
Runs `change-log-mode-hook'.
\\{change-log-mode-map}"
  (setq left-margin 8
        fill-column 74
        indent-tabs-mode t
        tab-width 8)
  (set (make-local-variable 'fill-paragraph-function)
       'change-log-fill-paragraph)
  (set (make-local-variable 'indent-line-function) 'add-log-indent)
  (set (make-local-variable 'tab-always-indent) nil)
  ;; We really do want "^" in paragraph-start below: it is only the
  ;; lines that begin at column 0 (despite the left-margin of 8) that
  ;; we are looking for.  Adding `* ' allows eliding the blank line
  ;; between entries for different files.
  (set (make-local-variable 'paragraph-start) "\\s *$\\|\f\\|^\\<")
  (set (make-local-variable 'paragraph-separate) paragraph-start)
  ;; Match null string on the date-line so that the date-line
  ;; is grouped with what follows.
  (set (make-local-variable 'page-delimiter) "^\\<\\|^\f")
  (set (make-local-variable 'version-control) 'never)
  (set (make-local-variable 'smerge-resolve-function)
       'change-log-resolve-conflict)
  (set (make-local-variable 'adaptive-fill-regexp) "\\s *")
  (set (make-local-variable 'font-lock-defaults)
       '(change-log-font-lock-keywords t nil nil backward-paragraph)))

;; It might be nice to have a general feature to replace this.  The idea I
;; have is a variable giving a regexp matching text which should not be
;; moved from bol by filling.  change-log-mode would set this to "^\\s *\\s(".
;; But I don't feel up to implementing that today.
(defun change-log-fill-paragraph (&optional justify)
  "Fill the paragraph, but preserve open parentheses at beginning of lines.
Prefix arg means justify as well."
  (interactive "P")
  (let ((end (progn (forward-paragraph) (point)))
        (beg (progn (backward-paragraph) (point)))
        (paragraph-start (concat paragraph-start "\\|\\s *\\s(")))
    (fill-region beg end justify)
    t))
\f
(defcustom add-log-current-defun-header-regexp
  "^\\([[:upper:]][[:upper:]_ ]*[[:upper:]_]\\|[-_[:alpha:]]+\\)[ \t]*[:=]"
  "*Heuristic regexp used by `add-log-current-defun' for unknown major modes."
  :type 'regexp
  :group 'change-log)

;;;###autoload
(defvar add-log-lisp-like-modes
    '(emacs-lisp-mode lisp-mode scheme-mode dsssl-mode lisp-interaction-mode)
  "*Modes that look like Lisp to `add-log-current-defun'.")

;;;###autoload
(defvar add-log-c-like-modes
    '(c-mode c++-mode c++-c-mode objc-mode)
  "*Modes that look like C to `add-log-current-defun'.")

;;;###autoload
(defvar add-log-tex-like-modes
    '(TeX-mode plain-TeX-mode LaTeX-mode plain-tex-mode latex-mode)
  "*Modes that look like TeX to `add-log-current-defun'.")

;;;###autoload
(defun add-log-current-defun ()
  "Return name of function definition point is in, or nil.

Understands C, Lisp, LaTeX (\"functions\" are chapters, sections, ...),
Texinfo (@node titles) and Perl.

Other modes are handled by a heuristic that looks in the 10K before
point for uppercase headings starting in the first column or
identifiers followed by `:' or `='.  See variables
`add-log-current-defun-header-regexp' and
`add-log-current-defun-function'.

Has a preference of looking backwards."
  (condition-case nil
      (save-excursion
        (let ((location (point)))
          (cond (add-log-current-defun-function
                 (funcall add-log-current-defun-function))
                ((memq major-mode add-log-lisp-like-modes)
                 ;; If we are now precisely at the beginning of a defun,
                 ;; make sure beginning-of-defun finds that one
                 ;; rather than the previous one.
                 (or (eobp) (forward-char 1))
                 (beginning-of-defun)
                 ;; Make sure we are really inside the defun found,
                 ;; not after it.
                 (when (and (looking-at "\\s(")
                            (progn (end-of-defun)
                                   (< location (point)))
                            (progn (forward-sexp -1)
                                   (>= location (point))))
                   (if (looking-at "\\s(")
                       (forward-char 1))
                   ;; Skip the defining construct name, typically "defun"
                   ;; or "defvar".
                   (forward-sexp 1)
                   ;; The second element is usually a symbol being defined.
                   ;; If it is not, use the first symbol in it.
                   (skip-chars-forward " \t\n'(")
                   (buffer-substring-no-properties (point)
                                                   (progn (forward-sexp 1)
                                                          (point)))))
                ((and (memq major-mode add-log-c-like-modes)
                      (save-excursion
                        (beginning-of-line)
                        ;; Use eq instead of = here to avoid
                        ;; error when at bob and char-after
                        ;; returns nil.
                        (while (eq (char-after (- (point) 2)) ?\\)
                          (forward-line -1))
                        (looking-at "[ \t]*#[ \t]*define[ \t]")))
                 ;; Handle a C macro definition.
                 (beginning-of-line)
                 (while (eq (char-after (- (point) 2)) ?\\) ;not =; note above
                   (forward-line -1))
                 (search-forward "define")
                 (skip-chars-forward " \t")
                 (buffer-substring-no-properties (point)
                                                 (progn (forward-sexp 1)
                                                        (point))))
                ((memq major-mode add-log-c-like-modes)
                 (beginning-of-line)
                 ;; See if we are in the beginning part of a function,
                 ;; before the open brace.  If so, advance forward.
                 (while (not (looking-at "{\\|\\(\\s *$\\)"))
                   (forward-line 1))
                 (or (eobp)
                     (forward-char 1))
                 (let (maybe-beg)
                   ;; Try to find the containing defun.
                   (beginning-of-defun)
                   (end-of-defun)
                   ;; If the defun we found ends before the desired position,
                   ;; see if there's a DEFUN construct
                   ;; between that end and the desired position.
                   (when (save-excursion
                           (and (> location (point))
                                (re-search-forward "^DEFUN"
                                                   (save-excursion
                                                     (goto-char location)
                                                     (line-end-position))
                                                   t)
                                (re-search-forward "^{" nil t)
                                (setq maybe-beg (point))))
                     ;; If so, go to the end of that instead.
                     (goto-char maybe-beg)
                     (end-of-defun)))
                 ;; If the desired position is within the defun we found,
                 ;; find the function name.
                 (when (< location (point))
                   (backward-sexp 1)
                   (let (beg tem)

                     (forward-line -1)
                     ;; Skip back over typedefs of arglist.
                     (while (and (not (bobp))
                                 (looking-at "[ \t\n]"))
                       (forward-line -1))
                     ;; See if this is using the DEFUN macro used in Emacs,
                     ;; or the DEFUN macro used by the C library.
                     (if (condition-case nil
                             (and (save-excursion
                                    (end-of-line)
                                    (while (= (preceding-char) ?\\)
                                      (end-of-line 2))
                                    (backward-sexp 1)
                                    (beginning-of-line)
                                    (setq tem (point))
                                    (looking-at "DEFUN\\b"))
                                  (>= location tem))
                           (error nil))
                         (progn
                           (goto-char tem)
                           (down-list 1)
                           (if (= (char-after (point)) ?\")
                               (progn
                                 (forward-sexp 1)
                                 (skip-chars-forward " ,")))
                           (buffer-substring-no-properties
                            (point)
                            (progn (forward-sexp 1)
                                   (point))))
                       (if (looking-at "^[+-]")
                           (change-log-get-method-definition)
                         ;; Ordinary C function syntax.
                         (setq beg (point))
                         (if (and
                              ;; Protect against "Unbalanced parens" error.
                              (condition-case nil
                                  (progn
                                    (down-list 1) ; into arglist
                                    (backward-up-list 1)
                                    (skip-chars-backward " \t")
                                    t)
                                (error nil))
                              ;; Verify initial pos was after
                              ;; real start of function.
                              (save-excursion
                                (goto-char beg)
                                ;; For this purpose, include the line
                                ;; that has the decl keywords.  This
                                ;; may also include some of the
                                ;; comments before the function.
                                (while (and (not (bobp))
                                            (save-excursion
                                              (forward-line -1)
                                              (looking-at "[^\n\f]")))
                                  (forward-line -1))
                                (>= location (point)))
                              ;; Consistency check: going down and up
                              ;; shouldn't take us back before BEG.
                              (> (point) beg))
                             (let (end middle)
                               ;; Don't include any final whitespace
                               ;; in the name we use.
                               (skip-chars-backward " \t\n")
                               (setq end (point))
                               (backward-sexp 1)
                               ;; Now find the right beginning of the name.
                               ;; Include certain keywords if they
                               ;; precede the name.
                               (setq middle (point))
                               (forward-word -1)
                               ;; Ignore these subparts of a class decl
                               ;; and move back to the class name itself.
                               (while (looking-at "public \\|private ")
                                 (skip-chars-backward " \t:")
                                 (setq end (point))
                                 (backward-sexp 1)
                                 (setq middle (point))
                                 (forward-word -1))
                               (and (bolp)
                                    (looking-at
                                     "enum \\|struct \\|union \\|class ")
                                    (setq middle (point)))
                               (goto-char end)
                               (when (eq (preceding-char) ?=)
                                 (forward-char -1)
                                 (skip-chars-backward " \t")
                                 (setq end (point)))
                               (buffer-substring-no-properties
                                middle end))))))))
                ((memq major-mode add-log-tex-like-modes)
                 (if (re-search-backward
                      "\\\\\\(sub\\)*\\(section\\|paragraph\\|chapter\\)"
                      nil t)
                     (progn
                       (goto-char (match-beginning 0))
                       (buffer-substring-no-properties
                        (1+ (point))    ; without initial backslash
                        (line-end-position)))))
                ((eq major-mode 'texinfo-mode)
                 (if (re-search-backward "^@node[ \t]+\\([^,\n]+\\)" nil t)
                     (match-string-no-properties 1)))
                ((memq major-mode '(perl-mode cperl-mode))
                 (if (re-search-backward "^sub[ \t]+\\([^({ \t\n]+\\)" nil t)
                     (match-string-no-properties 1)))
                ;; Emacs's autoconf-mode installs its own
                ;; `add-log-current-defun-function'.  This applies to
                ;; a different mode apparently for editing .m4
                ;; autoconf source.
                ((eq major-mode 'autoconf-mode)
                 (if (re-search-backward
                      "^\\(\\(m4_\\)?define\\|A._DEFUN\\)(\\[?\\([A-Za-z0-9_]+\\)" nil t)
                     (match-string-no-properties 3)))
                (t
                 ;; If all else fails, try heuristics
                 (let (case-fold-search
                       result)
                   (end-of-line)
                   (when (re-search-backward
                          add-log-current-defun-header-regexp
                          (- (point) 10000)
                          t)
                     (setq result (or (match-string-no-properties 1)
                                      (match-string-no-properties 0)))
                     ;; Strip whitespace away
                     (when (string-match "\\([^ \t\n\r\f].*[^ \t\n\r\f]\\)"
                                         result)
                       (setq result (match-string-no-properties 1 result)))
                     result))))))
    (error nil)))

(defvar change-log-get-method-definition-md)

;; Subroutine used within change-log-get-method-definition.
;; Add the last match in the buffer to the end of `md',
;; followed by the string END; move to the end of that match.
(defun change-log-get-method-definition-1 (end)
  (setq change-log-get-method-definition-md
        (concat change-log-get-method-definition-md
                (match-string 1)
                end))
  (goto-char (match-end 0)))

(defun change-log-get-method-definition ()
"For objective C, return the method name if we are in a method."
  (let ((change-log-get-method-definition-md "["))
    (save-excursion
      (if (re-search-backward "^@implementation\\s-*\\([A-Za-z_]*\\)" nil t)
          (change-log-get-method-definition-1 " ")))
    (save-excursion
      (cond
       ((re-search-forward "^\\([-+]\\)[ \t\n\f\r]*\\(([^)]*)\\)?\\s-*" nil t)
        (change-log-get-method-definition-1 "")
        (while (not (looking-at "[{;]"))
          (looking-at
           "\\([A-Za-z_]*:?\\)\\s-*\\(([^)]*)\\)?[A-Za-z_]*[ \t\n\f\r]*")
          (change-log-get-method-definition-1 ""))
        (concat change-log-get-method-definition-md "]"))))))
\f
(defun change-log-sortable-date-at ()
  "Return date of log entry in a consistent form for sorting.
Point is assumed to be at the start of the entry."
  (require 'timezone)
  (if (looking-at "^\\sw.........[0-9:+ ]*")
      (let ((date (match-string-no-properties 0)))
        (if date
            (if (string-match "\\(....\\)-\\(..\\)-\\(..\\)\\s-+" date)
                (concat (match-string 1 date) (match-string 2 date)
                        (match-string 3 date))
              (condition-case nil
                  (timezone-make-date-sortable date)
                (error nil)))))
    (error "Bad date")))

(defun change-log-resolve-conflict ()
  "Function to be used in `smerge-resolve-function'."
  (let ((buf (current-buffer)))
    (with-temp-buffer
      (insert-buffer-substring buf (match-beginning 1) (match-end 1))
      (save-match-data (change-log-mode))
      (let ((other-buf (current-buffer)))
        (with-current-buffer buf
          (save-excursion
            (save-restriction
              (narrow-to-region (match-beginning 0) (match-end 0))
              (replace-match (match-string 3) t t)
              (change-log-merge other-buf))))))))

;;;###autoload
(defun change-log-merge (other-log)
  "Merge the contents of ChangeLog file OTHER-LOG with this buffer.
Both must be found in Change Log mode (since the merging depends on
the appropriate motion commands).  OTHER-LOG can be either a file name
or a buffer.

Entries are inserted in chronological order.  Both the current and
old-style time formats for entries are supported."
  (interactive "*fLog file name to merge: ")
  (if (not (eq major-mode 'change-log-mode))
      (error "Not in Change Log mode"))
  (let ((other-buf (if (bufferp other-log) other-log
                     (find-file-noselect other-log)))
        (buf (current-buffer))
        date1 start end)
    (save-excursion
      (goto-char (point-min))
      (set-buffer other-buf)
      (goto-char (point-min))
      (if (not (eq major-mode 'change-log-mode))
          (error "%s not found in Change Log mode" other-log))
      ;; Loop through all the entries in OTHER-LOG.
      (while (not (eobp))
        (setq date1 (change-log-sortable-date-at))
        (setq start (point)
              end (progn (forward-page) (point)))
        ;; Look for an entry in original buffer that isn't later.
        (with-current-buffer buf
          (while (and (not (eobp))
                      (string< date1 (change-log-sortable-date-at)))
            (forward-page))
          (if (not (eobp))
              (insert-buffer-substring other-buf start end)
            ;; At the end of the original buffer, insert a newline to
            ;; separate entries and then the rest of the file being
            ;; merged.
            (unless (or (bobp)
                        (and (= ?\n (char-before))
                             (or (<= (1- (point)) (point-min))
                                 (= ?\n (char-before (1- (point)))))))
              (insert "\n"))
            ;; Move to the end of it to terminate outer loop.
            (with-current-buffer other-buf
              (goto-char (point-max)))
            (insert-buffer-substring other-buf start)))))))

;;;###autoload
(defun change-log-redate ()
  "Fix any old-style date entries in the current log file to default format."
  (interactive)
  (require 'timezone)
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward "^\\sw.........[0-9:+ ]*" nil t)
      (unless (= 12 (- (match-end 0) (match-beginning 0)))
        (let* ((date (save-match-data
                       (timezone-fix-time (match-string 0) nil nil)))
               (zone (if (consp (aref date 6))
                         (nth 1 (aref date 6)))))
          (replace-match (format-time-string
                          "%Y-%m-%d  "
                          (encode-time (aref date 5)
                                       (aref date 4)
                                       (aref date 3)
                                       (aref date 2)
                                       (aref date 1)
                                       (aref date 0)
                                       zone))))))))

(provide 'add-log)

;;; arch-tag: 81eee6fc-088f-4372-a37f-80ad9620e762
;;; add-log.el ends here