lisp/mail/metamail.el

   1 ;;; metamail.el --- Metamail interface for GNU Emacs
   2
   3 ;; Copyright (C) 1993, 1996, 2002, 2003, 2004,
   4 ;;   2005, 2006 Free Software Foundation, Inc.
   5
   6 ;; Author: Masanobu UMEDA <umerin@mse.kyutech.ac.jp>
   7 ;; Keywords: mail, news, mime, multimedia
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; Note: Metamail does not have all the options which are compatible with
  29 ;; the environment variables.  For that reason, metamail.el has to
  30 ;; hack the environment variables.  In addition, there is no way to
  31 ;; display all header fields without extra informative body messages
  32 ;; which are suppressed by the "-q" option.
  33
  34 ;; The idea of using metamail to process MIME messages is from
  35 ;; gnus-mime.el by Spike <Spike@world.std.com>.
  36
  37 ;;; Code:
  38
  39 (defvar rmail-current-message)
  40 (defvar rmail-message-vector)
  41
  42 (defgroup metamail nil
  43   "Metamail interface for Emacs."
  44   :group 'mail
  45   :group 'hypermedia
  46   :group 'processes)
  47
  48 (defcustom metamail-program-name "metamail"
  49   "*Metamail program name."
  50   :type 'string
  51   :group 'metamail)
  52
  53 (defcustom metamail-mailer-name "emacs"
  54   "*Mailer name set to MM_MAILER environment variable."
  55   :type 'string
  56   :group 'metamail)
  57
  58 (defvar metamail-environment '("KEYHEADS=*" "MM_QUIET=1")
  59   "*Environment variables passed to `metamail'.
  60 It must be a list of strings that have the format ENVVARNAME=VALUE.
  61 It is not expected to be altered globally by `set' or `setq'.
  62 Instead, change its value temporary using `let' or `let*' form.")
  63
  64 (defcustom metamail-switches '("-x" "-d" "-z")
  65   "*Switches for `metamail' program.
  66 `-z' is required to remove zap file.
  67 It is not expected to be altered globally by `set' or `setq'.
  68 Instead, change its value temporary using `let' or `let*' form.
  69 `-m MAILER' argument is automatically generated from the
  70 `metamail-mailer-name' variable."
  71   :type '(repeat (string :tag "Switch"))
  72   :group 'metamail)
  73
  74 ;;;###autoload
  75 (defun metamail-interpret-header ()
  76   "Interpret a header part of a MIME message in current buffer.
  77 Its body part is not interpreted at all."
  78   (interactive)
  79   (save-excursion
  80     (let* ((buffer-read-only nil)
  81            (metamail-switches           ;Inhibit processing an empty body.
  82             (append metamail-switches '("-c" "text/plain" "-E" "7bit")))
  83            (end (progn
  84                   (goto-char (point-min))
  85                   (search-forward "\n\n" nil 'move)
  86                   ;; An extra newline is inserted by metamail if there
  87                   ;; is no body part.  So, insert a dummy body by
  88                   ;; itself.
  89                   (insert "\n")
  90                   (point))))
  91       (metamail-region (point-min) end nil nil 'nodisplay)
  92       ;; Remove an extra newline inserted by myself.
  93       (goto-char (point-min))
  94       (if (search-forward "\n\n\n" nil t)
  95           (delete-char -1))
  96       )))
  97
  98 ;;;###autoload
  99 (defun metamail-interpret-body (&optional viewmode nodisplay)
 100   "Interpret a body part of a MIME message in current buffer.
 101 Optional argument VIEWMODE specifies the value of the
 102 EMACS_VIEW_MODE environment variable (defaulted to 1).
 103 Optional argument NODISPLAY non-nil means buffer is not
 104 redisplayed as output is inserted.
 105 Its header part is not interpreted at all."
 106   (interactive "p")
 107   (save-excursion
 108     (let ((contype nil)
 109           (encoding nil)
 110           (end (progn
 111                  (goto-char (point-min))
 112                  (search-forward "\n\n" nil t)
 113                  (point))))
 114       ;; Find Content-Type and Content-Transfer-Encoding from the header.
 115       (save-restriction
 116         (narrow-to-region (point-min) end)
 117         (setq contype
 118               (or (mail-fetch-field "Content-Type") "text/plain"))
 119         (setq encoding
 120               (or (mail-fetch-field "Content-Transfer-Encoding") "7bit")))
 121       ;; Interpret the body part only.
 122       (let ((metamail-switches          ;Process body part only.
 123              (append metamail-switches
 124                      (list "-b" "-c" contype "-E" encoding))))
 125         (metamail-region end (point-max) viewmode nil nodisplay))
 126       ;; Mode specific hack.
 127       (cond ((eq major-mode 'rmail-mode)
 128              ;; Adjust the marker of this message if in Rmail mode buffer.
 129              (set-marker (aref rmail-message-vector (1+ rmail-current-message))
 130                          (point-max))))
 131       )))
 132
 133 ;;;###autoload
 134 (defun metamail-buffer (&optional viewmode buffer nodisplay)
 135   "Process current buffer through `metamail'.
 136 Optional argument VIEWMODE specifies the value of the
 137 EMACS_VIEW_MODE environment variable (defaulted to 1).
 138 Optional argument BUFFER specifies a buffer to be filled (nil
 139 means current).
 140 Optional argument NODISPLAY non-nil means buffer is not
 141 redisplayed as output is inserted."
 142   (interactive "p")
 143   (metamail-region (point-min) (point-max) viewmode buffer nodisplay))
 144
 145 ;;;###autoload
 146 (defun metamail-region (beg end &optional viewmode buffer nodisplay)
 147   "Process current region through 'metamail'.
 148 Optional argument VIEWMODE specifies the value of the
 149 EMACS_VIEW_MODE environment variable (defaulted to 1).
 150 Optional argument BUFFER specifies a buffer to be filled (nil
 151 means current).
 152 Optional argument NODISPLAY non-nil means buffer is not
 153 redisplayed as output is inserted."
 154   (interactive "r\np")
 155   (let ((curbuf (current-buffer))
 156         (buffer-read-only nil)
 157         (metafile (make-temp-file "metamail"))
 158         (option-environment
 159          (list (format "EMACS_VIEW_MODE=%d"
 160                        (if (numberp viewmode) viewmode 1)))))
 161     (save-excursion
 162       ;; Gee!  Metamail does not ouput to stdout if input comes from
 163       ;; stdin.
 164       (let ((selective-display nil))    ;Disable ^M to nl translation.
 165         (write-region beg end metafile nil 'nomessage))
 166       (if buffer
 167           (set-buffer buffer))
 168       (setq buffer-read-only nil)
 169       ;; Clear destination buffer.
 170       (if (eq curbuf (current-buffer))
 171           (delete-region beg end)
 172         (delete-region (point-min) (point-max)))
 173       ;; We have to pass the environment variable KEYHEADS to display
 174       ;; all header fields.  Metamail should have an optional argument
 175       ;; to pass such information directly.
 176       (let ((process-environment
 177              (append process-environment
 178                      metamail-environment option-environment))
 179             (coding-system-for-read 'undecided))
 180         (apply (function call-process)
 181                metamail-program-name
 182                nil
 183                t                        ;Output to current buffer
 184                (not nodisplay)          ;Force redisplay
 185                (append metamail-switches
 186                        (list "-m" (or metamail-mailer-name "emacs"))
 187                        (list metafile))))
 188       ;; `metamail' may not delete the temporary file!
 189       (condition-case error
 190           (delete-file metafile)
 191         (error nil))
 192       )))
 193
 194 (provide 'metamail)
 195
 196 ;;; arch-tag: 52c0cb6f-d800-4776-9789-f0275cb5490e
 197 ;;; metamail.el ends here