Commit | Line | Data |
---|---|---|
23f87bed MB |
1 | ;;; mm-encode.el --- Functions for encoding MIME things |
2 | ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004 | |
3 | ;; Free Software Foundation, Inc. | |
c113de23 GM |
4 | |
5 | ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org> | |
6 | ;; MORIOKA Tomohiko <morioka@jaist.ac.jp> | |
7 | ;; This file is part of GNU Emacs. | |
8 | ||
9 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
10 | ;; it under the terms of the GNU General Public License as published by | |
11 | ;; the Free Software Foundation; either version 2, or (at your option) | |
12 | ;; any later version. | |
13 | ||
14 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
15 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | ;; GNU General Public License for more details. | |
18 | ||
19 | ;; You should have received a copy of the GNU General Public License | |
20 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
21 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | ;; Boston, MA 02111-1307, USA. | |
23 | ||
24 | ;;; Commentary: | |
25 | ||
26 | ;;; Code: | |
27 | ||
b28ce55a | 28 | (eval-when-compile (require 'cl)) |
c113de23 GM |
29 | (require 'mail-parse) |
30 | (require 'mailcap) | |
4515227f | 31 | (eval-and-compile |
23f87bed MB |
32 | (autoload 'mm-body-7-or-8 "mm-bodies") |
33 | (autoload 'mm-long-lines-p "mm-bodies")) | |
c113de23 | 34 | |
23f87bed | 35 | (defcustom mm-content-transfer-encoding-defaults |
c113de23 GM |
36 | '(("text/x-patch" 8bit) |
37 | ("text/.*" qp-or-base64) | |
38 | ("message/rfc822" 8bit) | |
23f87bed MB |
39 | ("application/emacs-lisp" qp-or-base64) |
40 | ("application/x-emacs-lisp" qp-or-base64) | |
41 | ("application/x-patch" qp-or-base64) | |
5be28abc | 42 | (".*" base64)) |
c113de23 GM |
43 | "Alist of regexps that match MIME types and their encodings. |
44 | If the encoding is `qp-or-base64', then either quoted-printable | |
23f87bed MB |
45 | or base64 will be used, depending on what is more efficient. |
46 | ||
47 | `qp-or-base64' has another effect. It will fold long lines so that | |
48 | MIME parts may not be broken by MTA. So do `quoted-printable' and | |
49 | `base64'. | |
50 | ||
51 | Note: It affects body encoding only when a part is a raw forwarded | |
52 | message (which will be made by `gnus-summary-mail-forward' with the | |
53 | arg 2 for example) or is neither the text/* type nor the message/* | |
54 | type. Even though in those cases, you can use the `encoding' MML tag | |
55 | to specify encoding of non-ASCII MIME parts." | |
56 | :type '(repeat (list (regexp :tag "MIME type") | |
57 | (choice :tag "encoding" | |
58 | (const 7bit) | |
59 | (const 8bit) | |
60 | (const qp-or-base64) | |
61 | (const quoted-printable) | |
62 | (const base64)))) | |
63 | :group 'mime) | |
c113de23 GM |
64 | |
65 | (defvar mm-use-ultra-safe-encoding nil | |
66 | "If non-nil, use encodings aimed at Procrustean bed survival. | |
67 | ||
68 | This means that textual parts are encoded as quoted-printable if they | |
69 | contain lines longer than 76 characters or starting with \"From \" in | |
70 | the body. Non-7bit encodings (8bit, binary) are generally disallowed. | |
71 | This is to reduce the probability that a broken MTA or MDA changes the | |
72 | message. | |
73 | ||
74 | This variable should never be set directly, but bound before a call to | |
75 | `mml-generate-mime' or similar functions.") | |
76 | ||
77 | (defun mm-insert-rfc822-headers (charset encoding) | |
78 | "Insert text/plain headers with CHARSET and ENCODING." | |
79 | (insert "MIME-Version: 1.0\n") | |
80 | (insert "Content-Type: text/plain; charset=" | |
81 | (mail-quote-string (downcase (symbol-name charset))) "\n") | |
82 | (insert "Content-Transfer-Encoding: " | |
83 | (downcase (symbol-name encoding)) "\n")) | |
84 | ||
85 | (defun mm-insert-multipart-headers () | |
86 | "Insert multipart/mixed headers." | |
87 | (let ((boundary "=-=-=")) | |
88 | (insert "MIME-Version: 1.0\n") | |
89 | (insert "Content-Type: multipart/mixed; boundary=\"" boundary "\"\n") | |
90 | boundary)) | |
91 | ||
92 | (defun mm-default-file-encoding (file) | |
93 | "Return a default encoding for FILE." | |
94 | (if (not (string-match "\\.[^.]+$" file)) | |
95 | "application/octet-stream" | |
96 | (mailcap-extension-to-mime (match-string 0 file)))) | |
97 | ||
98 | (defun mm-safer-encoding (encoding) | |
23f87bed | 99 | "Return an encoding similar to ENCODING but safer than it." |
c113de23 | 100 | (cond |
23f87bed MB |
101 | ((eq encoding '7bit) '7bit) ;; 7bit is considered safe. |
102 | ((memq encoding '(8bit quoted-printable)) 'quoted-printable) | |
8f688cb0 | 103 | ;; The remaining encodings are binary and base64 (and perhaps some |
c113de23 GM |
104 | ;; non-standard ones), which are both turned into base64. |
105 | (t 'base64))) | |
106 | ||
107 | (defun mm-encode-content-transfer-encoding (encoding &optional type) | |
23f87bed MB |
108 | "Encode the current buffer with ENCODING for MIME type TYPE. |
109 | ENCODING can be: nil (do nothing); one of `quoted-printable', `base64'; | |
110 | `7bit', `8bit' or `binary' (all do nothing); a function to do the encoding." | |
c113de23 GM |
111 | (cond |
112 | ((eq encoding 'quoted-printable) | |
23f87bed MB |
113 | ;; This used to try to make a multibyte buffer unibyte. That's |
114 | ;; completely wrong, since you'd get QP-encoded emacs-mule. If | |
115 | ;; this gets run on multibyte text it's an error that needs | |
116 | ;; fixing, and the encoding function will signal an error. | |
117 | ;; Likewise base64 below. | |
c113de23 GM |
118 | (quoted-printable-encode-region (point-min) (point-max) t)) |
119 | ((eq encoding 'base64) | |
120 | (when (equal type "text/plain") | |
121 | (goto-char (point-min)) | |
122 | (while (search-forward "\n" nil t) | |
123 | (replace-match "\r\n" t t))) | |
23f87bed | 124 | (base64-encode-region (point-min) (point-max))) |
c113de23 GM |
125 | ((memq encoding '(7bit 8bit binary)) |
126 | ;; Do nothing. | |
127 | ) | |
128 | ((null encoding) | |
129 | ;; Do nothing. | |
130 | ) | |
23f87bed | 131 | ;; Fixme: Ignoring errors here looks bogus. |
c113de23 GM |
132 | ((functionp encoding) |
133 | (ignore-errors (funcall encoding (point-min) (point-max)))) | |
134 | (t | |
23f87bed | 135 | (error "Unknown encoding %s" encoding)))) |
c113de23 GM |
136 | |
137 | (defun mm-encode-buffer (type) | |
23f87bed MB |
138 | "Encode the buffer which contains data of MIME type TYPE. |
139 | TYPE is a string or a list of the components. | |
c113de23 GM |
140 | The encoding used is returned." |
141 | (let* ((mime-type (if (stringp type) type (car type))) | |
142 | (encoding | |
143 | (or (and (listp type) | |
144 | (cadr (assq 'encoding type))) | |
145 | (mm-content-transfer-encoding mime-type))) | |
146 | (bits (mm-body-7-or-8))) | |
147 | ;; We force buffers that are 7bit to be unencoded, no matter | |
148 | ;; what the preferred encoding is. | |
23f87bed MB |
149 | ;; Only if the buffers don't contain lone lines. |
150 | (when (and (eq bits '7bit) (not (mm-long-lines-p 76))) | |
c113de23 GM |
151 | (setq encoding bits)) |
152 | (mm-encode-content-transfer-encoding encoding mime-type) | |
153 | encoding)) | |
154 | ||
155 | (defun mm-insert-headers (type encoding &optional file) | |
156 | "Insert headers for TYPE." | |
157 | (insert "Content-Type: " type) | |
158 | (when file | |
159 | (insert ";\n\tname=\"" (file-name-nondirectory file) "\"")) | |
160 | (insert "\n") | |
161 | (insert (format "Content-Transfer-Encoding: %s\n" encoding)) | |
162 | (insert "Content-Disposition: inline") | |
163 | (when file | |
164 | (insert ";\n\tfilename=\"" (file-name-nondirectory file) "\"")) | |
165 | (insert "\n") | |
166 | (insert "\n")) | |
167 | ||
168 | (defun mm-content-transfer-encoding (type) | |
169 | "Return a CTE suitable for TYPE to encode the current buffer." | |
170 | (let ((rules mm-content-transfer-encoding-defaults)) | |
171 | (catch 'found | |
172 | (while rules | |
173 | (when (string-match (caar rules) type) | |
174 | (throw 'found | |
a1506d29 | 175 | (let ((encoding |
c113de23 GM |
176 | (if (eq (cadr (car rules)) 'qp-or-base64) |
177 | (mm-qp-or-base64) | |
178 | (cadr (car rules))))) | |
179 | (if mm-use-ultra-safe-encoding | |
180 | (mm-safer-encoding encoding) | |
181 | encoding)))) | |
182 | (pop rules))))) | |
183 | ||
184 | (defun mm-qp-or-base64 () | |
23f87bed MB |
185 | "Return the type with which to encode the buffer. |
186 | This is either `base64' or `quoted-printable'." | |
187 | (if (equal mm-use-ultra-safe-encoding '(sign . "pgp")) | |
188 | ;; perhaps not always accurate? | |
189 | 'quoted-printable | |
190 | (save-excursion | |
191 | (let ((limit (min (point-max) (+ 2000 (point-min)))) | |
192 | (n8bit 0)) | |
193 | (goto-char (point-min)) | |
194 | (skip-chars-forward "\x20-\x7f\r\n\t" limit) | |
195 | (while (< (point) limit) | |
196 | (incf n8bit) | |
197 | (forward-char 1) | |
198 | (skip-chars-forward "\x20-\x7f\r\n\t" limit)) | |
199 | (if (or (< (* 6 n8bit) (- limit (point-min))) | |
200 | ;; Don't base64, say, a short line with a single | |
201 | ;; non-ASCII char when splitting parts by charset. | |
202 | (= n8bit 1)) | |
203 | 'quoted-printable | |
204 | 'base64))))) | |
c113de23 GM |
205 | |
206 | (provide 'mm-encode) | |
207 | ||
ab5796a9 | 208 | ;;; arch-tag: 7d01bba4-d469-4851-952b-dc863f84ed66 |
c113de23 | 209 | ;;; mm-encode.el ends here |