lisp/mail/metamail.el

   1 ;;; metamail.el --- Metamail interface for GNU Emacs
   2
   3 ;; Copyright (C) 1993, 1996, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 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 3 of the License, or
  14 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Note: Metamail does not have all the options which are compatible with
  27 ;; the environment variables.  For that reason, metamail.el has to
  28 ;; hack the environment variables.  In addition, there is no way to
  29 ;; display all header fields without extra informative body messages
  30 ;; which are suppressed by the "-q" option.
  31
  32 ;; The idea of using metamail to process MIME messages is from
  33 ;; gnus-mime.el by Spike <Spike@world.std.com>.
  34
  35 ;;; Code:
  36
  37 (defvar rmail-current-message)
  38 (defvar rmail-message-vector)
  39
  40 (defgroup metamail nil
  41   "Metamail interface for Emacs."
  42   :group 'mail
  43   :group 'hypermedia
  44   :group 'processes)
  45
  46 (defcustom metamail-program-name "metamail"
  47   "*Metamail program name."
  48   :type 'string
  49   :group 'metamail)
  50
  51 (defcustom metamail-mailer-name "emacs"
  52   "*Mailer name set to MM_MAILER environment variable."
  53   :type 'string
  54   :group 'metamail)
  55
  56 (defvar metamail-environment '("KEYHEADS=*" "MM_QUIET=1")
  57   "*Environment variables passed to `metamail'.
  58 It must be a list of strings that have the format ENVVARNAME=VALUE.
  59 It is not expected to be altered globally by `set' or `setq'.
  60 Instead, change its value temporary using `let' or `let*' form.")
  61
  62 (defcustom metamail-switches '("-x" "-d" "-z")
  63   "*Switches for `metamail' program.
  64 `-z' is required to remove zap file.
  65 It is not expected to be altered globally by `set' or `setq'.
  66 Instead, change its value temporary using `let' or `let*' form.
  67 `-m MAILER' argument is automatically generated from the
  68 `metamail-mailer-name' variable."
  69   :type '(repeat (string :tag "Switch"))
  70   :group 'metamail)
  71
  72 ;;;###autoload
  73 (defun metamail-interpret-header ()
  74   "Interpret a header part of a MIME message in current buffer.
  75 Its body part is not interpreted at all."
  76   (interactive)
  77   (save-excursion
  78     (let* ((buffer-read-only nil)
  79            (metamail-switches           ;Inhibit processing an empty body.
  80             (append metamail-switches '("-c" "text/plain" "-E" "7bit")))
  81            (end (progn
  82                   (goto-char (point-min))
  83                   (search-forward "\n\n" nil 'move)
  84                   ;; An extra newline is inserted by metamail if there
  85                   ;; is no body part.  So, insert a dummy body by
  86                   ;; itself.
  87                   (insert "\n")
  88                   (point))))
  89       (metamail-region (point-min) end nil nil 'nodisplay)
  90       ;; Remove an extra newline inserted by myself.
  91       (goto-char (point-min))
  92       (if (search-forward "\n\n\n" nil t)
  93           (delete-char -1))
  94       )))
  95
  96 ;;;###autoload
  97 (defun metamail-interpret-body (&optional viewmode nodisplay)
  98   "Interpret a body part of a MIME message in current buffer.
  99 Optional argument VIEWMODE specifies the value of the
 100 EMACS_VIEW_MODE environment variable (defaulted to 1).
 101 Optional argument NODISPLAY non-nil means buffer is not
 102 redisplayed as output is inserted.
 103 Its header part is not interpreted at all."
 104   (interactive "p")
 105   (save-excursion
 106     (let ((contype nil)
 107           (encoding nil)
 108           (end (progn
 109                  (goto-char (point-min))
 110                  (search-forward "\n\n" nil t)
 111                  (point))))
 112       ;; Find Content-Type and Content-Transfer-Encoding from the header.
 113       (save-restriction
 114         (narrow-to-region (point-min) end)
 115         (setq contype
 116               (or (mail-fetch-field "Content-Type") "text/plain"))
 117         (setq encoding
 118               (or (mail-fetch-field "Content-Transfer-Encoding") "7bit")))
 119       ;; Interpret the body part only.
 120       (let ((metamail-switches          ;Process body part only.
 121              (append metamail-switches
 122                      (list "-b" "-c" contype "-E" encoding))))
 123         (metamail-region end (point-max) viewmode nil nodisplay))
 124       ;; This mode specific hack is no longer appropriate in mbox Rmail.
 125       ;; Pre-mbox, we have just modified the actual folder, so we
 126       ;; update the message-vector with the new end position of the
 127       ;; current message.  In mbox Rmail, all we have done is modify a
 128       ;; display copy of the message.  Note also that point-max is a
 129       ;; marker in the wrong buffer: the message-vector contains
 130       ;; markers in rmail-view-buffer (which is not in rmail-mode).
 131       ;; So this hack actually breaks the message-vector.
 132       ;; If you're calling this on the actual rmail-view-buffer (or a
 133       ;; non-swapped rmail-buffer), you would still need this hack.
 134       ;; But you're not going to do that.
 135 ;;;      (cond ((eq major-mode 'rmail-mode)
 136 ;;;          ;; Adjust the marker of this message if in Rmail mode buffer.
 137 ;;;          (set-marker (aref rmail-message-vector (1+ rmail-current-message))
 138 ;;;                      (point-max))))
 139       )))
 140
 141 ;;;###autoload
 142 (defun metamail-buffer (&optional viewmode buffer nodisplay)
 143   "Process current buffer through `metamail'.
 144 Optional argument VIEWMODE specifies the value of the
 145 EMACS_VIEW_MODE environment variable (defaulted to 1).
 146 Optional argument BUFFER specifies a buffer to be filled (nil
 147 means current).
 148 Optional argument NODISPLAY non-nil means buffer is not
 149 redisplayed as output is inserted."
 150   (interactive "p")
 151   (metamail-region (point-min) (point-max) viewmode buffer nodisplay))
 152
 153 ;;;###autoload
 154 (defun metamail-region (beg end &optional viewmode buffer nodisplay)
 155   "Process current region through 'metamail'.
 156 Optional argument VIEWMODE specifies the value of the
 157 EMACS_VIEW_MODE environment variable (defaulted to 1).
 158 Optional argument BUFFER specifies a buffer to be filled (nil
 159 means current).
 160 Optional argument NODISPLAY non-nil means buffer is not
 161 redisplayed as output is inserted."
 162   (interactive "r\np")
 163   (let ((curbuf (current-buffer))
 164         (buffer-read-only nil)
 165         (metafile (make-temp-file "metamail"))
 166         (option-environment
 167          (list (format "EMACS_VIEW_MODE=%d"
 168                        (if (numberp viewmode) viewmode 1)))))
 169     (save-excursion
 170       ;; Gee!  Metamail does not ouput to stdout if input comes from
 171       ;; stdin.
 172       (let ((selective-display nil))    ;Disable ^M to nl translation.
 173         (write-region beg end metafile nil 'nomessage))
 174       (if buffer
 175           (set-buffer buffer))
 176       (setq buffer-read-only nil)
 177       ;; Clear destination buffer.
 178       (if (eq curbuf (current-buffer))
 179           (delete-region beg end)
 180         (delete-region (point-min) (point-max)))
 181       ;; We have to pass the environment variable KEYHEADS to display
 182       ;; all header fields.  Metamail should have an optional argument
 183       ;; to pass such information directly.
 184       (let ((process-environment
 185              (append process-environment
 186                      metamail-environment option-environment))
 187             (coding-system-for-read 'undecided))
 188         (apply (function call-process)
 189                metamail-program-name
 190                nil
 191                t                        ;Output to current buffer
 192                (not nodisplay)          ;Force redisplay
 193                (append metamail-switches
 194                        (list "-m" (or metamail-mailer-name "emacs"))
 195                        (list metafile))))
 196       ;; `metamail' may not delete the temporary file!
 197       (condition-case error
 198           (delete-file metafile)
 199         (error nil))
 200       )))
 201
 202 (provide 'metamail)
 203
 204 ;; arch-tag: 52c0cb6f-d800-4776-9789-f0275cb5490e
 205 ;;; metamail.el ends here