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23f87bed | 1 | ;;; mm-encode.el --- Functions for encoding MIME things |
e84b4b86 | 2 | |
ba318903 | 3 | ;; Copyright (C) 1998-2014 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 | ||
5e809f55 | 9 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
c113de23 | 10 | ;; it under the terms of the GNU General Public License as published by |
5e809f55 GM |
11 | ;; the Free Software Foundation, either version 3 of the License, or |
12 | ;; (at your option) any later version. | |
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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 | |
5e809f55 | 16 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
c113de23 GM |
17 | ;; GNU General Public License for more details. |
18 | ||
19 | ;; You should have received a copy of the GNU General Public License | |
5e809f55 | 20 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
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21 | |
22 | ;;; Commentary: | |
23 | ||
24 | ;;; Code: | |
25 | ||
b28ce55a | 26 | (eval-when-compile (require 'cl)) |
c113de23 | 27 | (require 'mail-parse) |
aa8f8277 | 28 | (autoload 'mailcap-extension-to-mime "mailcap") |
8abf1b22 GM |
29 | (autoload 'mm-body-7-or-8 "mm-bodies") |
30 | (autoload 'mm-long-lines-p "mm-bodies") | |
c113de23 | 31 | |
23f87bed | 32 | (defcustom mm-content-transfer-encoding-defaults |
c113de23 GM |
33 | '(("text/x-patch" 8bit) |
34 | ("text/.*" qp-or-base64) | |
35 | ("message/rfc822" 8bit) | |
23f87bed MB |
36 | ("application/emacs-lisp" qp-or-base64) |
37 | ("application/x-emacs-lisp" qp-or-base64) | |
38 | ("application/x-patch" qp-or-base64) | |
5be28abc | 39 | (".*" base64)) |
c113de23 GM |
40 | "Alist of regexps that match MIME types and their encodings. |
41 | If the encoding is `qp-or-base64', then either quoted-printable | |
23f87bed MB |
42 | or base64 will be used, depending on what is more efficient. |
43 | ||
a3f57c41 G |
44 | This list is only consulted when encoding MIME parts in the |
45 | bodies -- not for the regular non-MIME-ish messages." | |
23f87bed MB |
46 | :type '(repeat (list (regexp :tag "MIME type") |
47 | (choice :tag "encoding" | |
48 | (const 7bit) | |
49 | (const 8bit) | |
50 | (const qp-or-base64) | |
51 | (const quoted-printable) | |
52 | (const base64)))) | |
53 | :group 'mime) | |
c113de23 | 54 | |
54c72c31 KY |
55 | (defcustom mm-sign-option nil |
56 | "Option how to create signed parts. | |
57 | nil, use the default keys without asking; | |
58 | `guided', let you select signing keys from the menu." | |
029dda9c | 59 | :version "23.2" ;; No Gnus 0.12 |
54c72c31 KY |
60 | :type '(choice (item guided) |
61 | (item :tag "default" nil)) | |
62 | :group 'mime-security) | |
63 | ||
64 | (defcustom mm-encrypt-option nil | |
65 | "Option how to create encrypted parts. | |
66 | nil, use the default keys without asking; | |
67 | `guided', let you select recipients' keys from the menu." | |
029dda9c | 68 | :version "23.2" ;; No Gnus 0.12 |
54c72c31 KY |
69 | :type '(choice (item guided) |
70 | (item :tag "default" nil)) | |
71 | :group 'mime-security) | |
72 | ||
c113de23 GM |
73 | (defvar mm-use-ultra-safe-encoding nil |
74 | "If non-nil, use encodings aimed at Procrustean bed survival. | |
75 | ||
76 | This means that textual parts are encoded as quoted-printable if they | |
77 | contain lines longer than 76 characters or starting with \"From \" in | |
78 | the body. Non-7bit encodings (8bit, binary) are generally disallowed. | |
79 | This is to reduce the probability that a broken MTA or MDA changes the | |
80 | message. | |
81 | ||
82 | This variable should never be set directly, but bound before a call to | |
83 | `mml-generate-mime' or similar functions.") | |
84 | ||
85 | (defun mm-insert-rfc822-headers (charset encoding) | |
86 | "Insert text/plain headers with CHARSET and ENCODING." | |
87 | (insert "MIME-Version: 1.0\n") | |
88 | (insert "Content-Type: text/plain; charset=" | |
89 | (mail-quote-string (downcase (symbol-name charset))) "\n") | |
90 | (insert "Content-Transfer-Encoding: " | |
91 | (downcase (symbol-name encoding)) "\n")) | |
92 | ||
93 | (defun mm-insert-multipart-headers () | |
94 | "Insert multipart/mixed headers." | |
95 | (let ((boundary "=-=-=")) | |
96 | (insert "MIME-Version: 1.0\n") | |
97 | (insert "Content-Type: multipart/mixed; boundary=\"" boundary "\"\n") | |
98 | boundary)) | |
99 | ||
c3760c17 | 100 | ;;;###autoload |
c113de23 GM |
101 | (defun mm-default-file-encoding (file) |
102 | "Return a default encoding for FILE." | |
103 | (if (not (string-match "\\.[^.]+$" file)) | |
104 | "application/octet-stream" | |
105 | (mailcap-extension-to-mime (match-string 0 file)))) | |
106 | ||
58a67d68 | 107 | (defun mm-safer-encoding (encoding &optional type) |
23f87bed | 108 | "Return an encoding similar to ENCODING but safer than it." |
c113de23 | 109 | (cond |
23f87bed | 110 | ((eq encoding '7bit) '7bit) ;; 7bit is considered safe. |
58a67d68 MB |
111 | ((memq encoding '(8bit quoted-printable)) |
112 | ;; According to RFC2046, 5.2.1, RFC822 Subtype, "quoted-printable" is not | |
113 | ;; a valid encoding for message/rfc822: | |
114 | ;; No encoding other than "7bit", "8bit", or "binary" is permitted for the | |
115 | ;; body of a "message/rfc822" entity. | |
116 | (if (string= type "message/rfc822") '8bit 'quoted-printable)) | |
8f688cb0 | 117 | ;; The remaining encodings are binary and base64 (and perhaps some |
c113de23 | 118 | ;; non-standard ones), which are both turned into base64. |
58a67d68 | 119 | (t (if (string= type "message/rfc822") 'binary 'base64)))) |
c113de23 GM |
120 | |
121 | (defun mm-encode-content-transfer-encoding (encoding &optional type) | |
23f87bed MB |
122 | "Encode the current buffer with ENCODING for MIME type TYPE. |
123 | ENCODING can be: nil (do nothing); one of `quoted-printable', `base64'; | |
124 | `7bit', `8bit' or `binary' (all do nothing); a function to do the encoding." | |
c113de23 GM |
125 | (cond |
126 | ((eq encoding 'quoted-printable) | |
23f87bed MB |
127 | ;; This used to try to make a multibyte buffer unibyte. That's |
128 | ;; completely wrong, since you'd get QP-encoded emacs-mule. If | |
129 | ;; this gets run on multibyte text it's an error that needs | |
130 | ;; fixing, and the encoding function will signal an error. | |
131 | ;; Likewise base64 below. | |
c113de23 GM |
132 | (quoted-printable-encode-region (point-min) (point-max) t)) |
133 | ((eq encoding 'base64) | |
4a2358e9 | 134 | (when (string-match "\\`text/" type) |
c113de23 GM |
135 | (goto-char (point-min)) |
136 | (while (search-forward "\n" nil t) | |
137 | (replace-match "\r\n" t t))) | |
23f87bed | 138 | (base64-encode-region (point-min) (point-max))) |
c113de23 GM |
139 | ((memq encoding '(7bit 8bit binary)) |
140 | ;; Do nothing. | |
141 | ) | |
142 | ((null encoding) | |
143 | ;; Do nothing. | |
144 | ) | |
23f87bed | 145 | ;; Fixme: Ignoring errors here looks bogus. |
c113de23 GM |
146 | ((functionp encoding) |
147 | (ignore-errors (funcall encoding (point-min) (point-max)))) | |
148 | (t | |
23f87bed | 149 | (error "Unknown encoding %s" encoding)))) |
c113de23 | 150 | |
de0bdfe7 KY |
151 | (defun mm-encode-buffer (type &optional encoding) |
152 | "Encode the buffer which contains data of MIME type TYPE by ENCODING. | |
23f87bed | 153 | TYPE is a string or a list of the components. |
de0bdfe7 KY |
154 | The optional ENCODING overrides the encoding determined according to |
155 | TYPE and `mm-content-transfer-encoding-defaults'. | |
c113de23 | 156 | The encoding used is returned." |
de0bdfe7 KY |
157 | (let ((mime-type (if (stringp type) type (car type)))) |
158 | (mm-encode-content-transfer-encoding | |
159 | (or encoding | |
160 | (setq encoding (or (and (listp type) | |
161 | (cadr (assq 'encoding type))) | |
162 | (mm-content-transfer-encoding mime-type)))) | |
163 | mime-type) | |
c113de23 GM |
164 | encoding)) |
165 | ||
166 | (defun mm-insert-headers (type encoding &optional file) | |
167 | "Insert headers for TYPE." | |
168 | (insert "Content-Type: " type) | |
169 | (when file | |
170 | (insert ";\n\tname=\"" (file-name-nondirectory file) "\"")) | |
171 | (insert "\n") | |
172 | (insert (format "Content-Transfer-Encoding: %s\n" encoding)) | |
173 | (insert "Content-Disposition: inline") | |
174 | (when file | |
175 | (insert ";\n\tfilename=\"" (file-name-nondirectory file) "\"")) | |
176 | (insert "\n") | |
177 | (insert "\n")) | |
178 | ||
179 | (defun mm-content-transfer-encoding (type) | |
180 | "Return a CTE suitable for TYPE to encode the current buffer." | |
181 | (let ((rules mm-content-transfer-encoding-defaults)) | |
182 | (catch 'found | |
183 | (while rules | |
184 | (when (string-match (caar rules) type) | |
185 | (throw 'found | |
a1506d29 | 186 | (let ((encoding |
c113de23 GM |
187 | (if (eq (cadr (car rules)) 'qp-or-base64) |
188 | (mm-qp-or-base64) | |
189 | (cadr (car rules))))) | |
190 | (if mm-use-ultra-safe-encoding | |
58a67d68 | 191 | (mm-safer-encoding encoding type) |
c113de23 GM |
192 | encoding)))) |
193 | (pop rules))))) | |
194 | ||
195 | (defun mm-qp-or-base64 () | |
23f87bed MB |
196 | "Return the type with which to encode the buffer. |
197 | This is either `base64' or `quoted-printable'." | |
198 | (if (equal mm-use-ultra-safe-encoding '(sign . "pgp")) | |
199 | ;; perhaps not always accurate? | |
200 | 'quoted-printable | |
201 | (save-excursion | |
202 | (let ((limit (min (point-max) (+ 2000 (point-min)))) | |
203 | (n8bit 0)) | |
204 | (goto-char (point-min)) | |
205 | (skip-chars-forward "\x20-\x7f\r\n\t" limit) | |
206 | (while (< (point) limit) | |
207 | (incf n8bit) | |
208 | (forward-char 1) | |
209 | (skip-chars-forward "\x20-\x7f\r\n\t" limit)) | |
210 | (if (or (< (* 6 n8bit) (- limit (point-min))) | |
211 | ;; Don't base64, say, a short line with a single | |
212 | ;; non-ASCII char when splitting parts by charset. | |
213 | (= n8bit 1)) | |
214 | 'quoted-printable | |
215 | 'base64))))) | |
c113de23 GM |
216 | |
217 | (provide 'mm-encode) | |
218 | ||
219 | ;;; mm-encode.el ends here |