4.4BSD/usr/src/contrib/emacs-18.57/lisp/rmailedit.el

;; "RMAIL edit mode"  Edit the current message.
;; Copyright (C) 1985 Free Software Foundation, Inc.

;; 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 1, 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, 675 Mass Ave, Cambridge, MA 02139, USA.


(require 'rmail)

(defvar rmail-edit-map nil)
(if rmail-edit-map
    nil
  (setq rmail-edit-map (copy-keymap text-mode-map))
  (define-key rmail-edit-map "\C-c\C-c" 'rmail-cease-edit)
  (define-key rmail-edit-map "\C-c\C-]" 'rmail-abort-edit))

;; Rmail Edit mode is suitable only for specially formatted data.
(put 'rmail-edit-mode 'mode-class 'special)

(defun rmail-edit-mode ()
  "Major mode for editing the contents of an RMAIL message.
The editing commands are the same as in Text mode, together with two commands
to return to regular RMAIL:
  *  rmail-abort-edit cancels the changes
     you have made and returns to RMAIL
  *  rmail-cease-edit makes them permanent.
\\{rmail-edit-map}"
  (use-local-map rmail-edit-map)
  (setq major-mode 'rmail-edit-mode)
  (setq mode-name "RMAIL Edit")
  (if (boundp 'mode-line-modified)
      (setq mode-line-modified (default-value 'mode-line-modified))
    (setq mode-line-format (default-value 'mode-line-format)))
  (run-hooks 'text-mode-hook 'rmail-edit-mode-hook))

(defun rmail-edit-current-message ()
  "Edit the contents of this message."
  (interactive)
  (rmail-edit-mode)
  (make-local-variable 'rmail-old-text)
  (setq rmail-old-text (buffer-substring (point-min) (point-max)))
  (setq buffer-read-only nil)
  (set-buffer-modified-p (buffer-modified-p))
  ;; Make mode line update.
  (if (and (eq (key-binding "\C-c\C-c") 'rmail-cease-edit)
	   (eq (key-binding "\C-c\C-]") 'rmail-abort-edit))
      (message "Editing: Type C-c C-c to return to Rmail, C-c C-] to abort")
    (message (substitute-command-keys
	       "Editing: Type \\[rmail-cease-edit] to return to Rmail, \\[rmail-abort-edit] to abort"))))

(defun rmail-cease-edit ()
  "Finish editing message; switch back to Rmail proper."
  (interactive)
  ;; Make sure buffer ends with a newline.
  (save-excursion
    (goto-char (point-max))
    (if (/= (preceding-char) ?\n)
	(insert "\n"))
    ;; Adjust the marker that points to the end of this message.
    (set-marker (aref rmail-message-vector (1+ rmail-current-message))
		(point)))
  (let ((old rmail-old-text))
    ;; Update the mode line.
    (set-buffer-modified-p (buffer-modified-p))
    (rmail-mode-1)
    (if (and (= (length old) (- (point-max) (point-min)))
	     (string= old (buffer-substring (point-min) (point-max))))
	()
      (setq old nil)
      (rmail-set-attribute "edited" t)
      (if (boundp 'rmail-summary-vector)
	  (progn
	    (aset rmail-summary-vector (1- rmail-current-message) nil)
	    (save-excursion
	      (rmail-widen-to-current-msgbeg
	        (function (lambda ()
			    (forward-line 2)
			    (if (looking-at "Summary-line: ")
				(let ((buffer-read-only nil))
				  (delete-region (point)
						 (progn (forward-line 1)
							(point))))))))
	      (rmail-show-message))))))
  (setq buffer-read-only t))

(defun rmail-abort-edit ()
  "Abort edit of current message; restore original contents."
  (interactive)
  (delete-region (point-min) (point-max))
  (insert rmail-old-text)
  (rmail-cease-edit))