1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
;;; mm-encode.el --- Functions for encoding MIME things
;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
;; 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; MORIOKA Tomohiko <morioka@jaist.ac.jp>
;; 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
(eval-when-compile (require 'cl))
(require 'mail-parse)
(require 'mailcap)
(autoload 'mm-body-7-or-8 "mm-bodies")
(autoload 'mm-long-lines-p "mm-bodies")
(defcustom mm-content-transfer-encoding-defaults
'(("text/x-patch" 8bit)
("text/.*" qp-or-base64)
("message/rfc822" 8bit)
("application/emacs-lisp" qp-or-base64)
("application/x-emacs-lisp" qp-or-base64)
("application/x-patch" qp-or-base64)
(".*" base64))
"Alist of regexps that match MIME types and their encodings.
If the encoding is `qp-or-base64', then either quoted-printable
or base64 will be used, depending on what is more efficient.
`qp-or-base64' has another effect. It will fold long lines so that
MIME parts may not be broken by MTA. So do `quoted-printable' and
`base64'.
Note: It affects body encoding only when a part is a raw forwarded
message (which will be made by `gnus-summary-mail-forward' with the
arg 2 for example) or is neither the text/* type nor the message/*
type. Even though in those cases, you can use the `encoding' MML tag
to specify encoding of non-ASCII MIME parts."
:type '(repeat (list (regexp :tag "MIME type")
(choice :tag "encoding"
(const 7bit)
(const 8bit)
(const qp-or-base64)
(const quoted-printable)
(const base64))))
:group 'mime)
(defcustom mm-sign-option nil
"Option how to create signed parts.
nil, use the default keys without asking;
`guided', let you select signing keys from the menu."
:version "23.2" ;; No Gnus 0.12
:type '(choice (item guided)
(item :tag "default" nil))
:group 'mime-security)
(defcustom mm-encrypt-option nil
"Option how to create encrypted parts.
nil, use the default keys without asking;
`guided', let you select recipients' keys from the menu."
:version "23.2" ;; No Gnus 0.12
:type '(choice (item guided)
(item :tag "default" nil))
:group 'mime-security)
(defvar mm-use-ultra-safe-encoding nil
"If non-nil, use encodings aimed at Procrustean bed survival.
This means that textual parts are encoded as quoted-printable if they
contain lines longer than 76 characters or starting with \"From \" in
the body. Non-7bit encodings (8bit, binary) are generally disallowed.
This is to reduce the probability that a broken MTA or MDA changes the
message.
This variable should never be set directly, but bound before a call to
`mml-generate-mime' or similar functions.")
(defun mm-insert-rfc822-headers (charset encoding)
"Insert text/plain headers with CHARSET and ENCODING."
(insert "MIME-Version: 1.0\n")
(insert "Content-Type: text/plain; charset="
(mail-quote-string (downcase (symbol-name charset))) "\n")
(insert "Content-Transfer-Encoding: "
(downcase (symbol-name encoding)) "\n"))
(defun mm-insert-multipart-headers ()
"Insert multipart/mixed headers."
(let ((boundary "=-=-="))
(insert "MIME-Version: 1.0\n")
(insert "Content-Type: multipart/mixed; boundary=\"" boundary "\"\n")
boundary))
(defun mm-default-file-encoding (file)
"Return a default encoding for FILE."
(if (not (string-match "\\.[^.]+$" file))
"application/octet-stream"
(mailcap-extension-to-mime (match-string 0 file))))
(defun mm-safer-encoding (encoding &optional type)
"Return an encoding similar to ENCODING but safer than it."
(cond
((eq encoding '7bit) '7bit) ;; 7bit is considered safe.
((memq encoding '(8bit quoted-printable))
;; According to RFC2046, 5.2.1, RFC822 Subtype, "quoted-printable" is not
;; a valid encoding for message/rfc822:
;; No encoding other than "7bit", "8bit", or "binary" is permitted for the
;; body of a "message/rfc822" entity.
(if (string= type "message/rfc822") '8bit 'quoted-printable))
;; The remaining encodings are binary and base64 (and perhaps some
;; non-standard ones), which are both turned into base64.
(t (if (string= type "message/rfc822") 'binary 'base64))))
(defun mm-encode-content-transfer-encoding (encoding &optional type)
"Encode the current buffer with ENCODING for MIME type TYPE.
ENCODING can be: nil (do nothing); one of `quoted-printable', `base64';
`7bit', `8bit' or `binary' (all do nothing); a function to do the encoding."
(cond
((eq encoding 'quoted-printable)
;; This used to try to make a multibyte buffer unibyte. That's
;; completely wrong, since you'd get QP-encoded emacs-mule. If
;; this gets run on multibyte text it's an error that needs
;; fixing, and the encoding function will signal an error.
;; Likewise base64 below.
(quoted-printable-encode-region (point-min) (point-max) t))
((eq encoding 'base64)
(when (string-match "\\`text/" type)
(goto-char (point-min))
(while (search-forward "\n" nil t)
(replace-match "\r\n" t t)))
(base64-encode-region (point-min) (point-max)))
((memq encoding '(7bit 8bit binary))
;; Do nothing.
)
((null encoding)
;; Do nothing.
)
;; Fixme: Ignoring errors here looks bogus.
((functionp encoding)
(ignore-errors (funcall encoding (point-min) (point-max))))
(t
(error "Unknown encoding %s" encoding))))
(defun mm-encode-buffer (type &optional encoding)
"Encode the buffer which contains data of MIME type TYPE by ENCODING.
TYPE is a string or a list of the components.
The optional ENCODING overrides the encoding determined according to
TYPE and `mm-content-transfer-encoding-defaults'.
The encoding used is returned."
(let ((mime-type (if (stringp type) type (car type))))
(mm-encode-content-transfer-encoding
(or encoding
(setq encoding (or (and (listp type)
(cadr (assq 'encoding type)))
(mm-content-transfer-encoding mime-type))))
mime-type)
encoding))
(defun mm-insert-headers (type encoding &optional file)
"Insert headers for TYPE."
(insert "Content-Type: " type)
(when file
(insert ";\n\tname=\"" (file-name-nondirectory file) "\""))
(insert "\n")
(insert (format "Content-Transfer-Encoding: %s\n" encoding))
(insert "Content-Disposition: inline")
(when file
(insert ";\n\tfilename=\"" (file-name-nondirectory file) "\""))
(insert "\n")
(insert "\n"))
(defun mm-content-transfer-encoding (type)
"Return a CTE suitable for TYPE to encode the current buffer."
(let ((rules mm-content-transfer-encoding-defaults))
(catch 'found
(while rules
(when (string-match (caar rules) type)
(throw 'found
(let ((encoding
(if (eq (cadr (car rules)) 'qp-or-base64)
(mm-qp-or-base64)
(cadr (car rules)))))
(if mm-use-ultra-safe-encoding
(mm-safer-encoding encoding type)
encoding))))
(pop rules)))))
(defun mm-qp-or-base64 ()
"Return the type with which to encode the buffer.
This is either `base64' or `quoted-printable'."
(if (equal mm-use-ultra-safe-encoding '(sign . "pgp"))
;; perhaps not always accurate?
'quoted-printable
(save-excursion
(let ((limit (min (point-max) (+ 2000 (point-min))))
(n8bit 0))
(goto-char (point-min))
(skip-chars-forward "\x20-\x7f\r\n\t" limit)
(while (< (point) limit)
(incf n8bit)
(forward-char 1)
(skip-chars-forward "\x20-\x7f\r\n\t" limit))
(if (or (< (* 6 n8bit) (- limit (point-min)))
;; Don't base64, say, a short line with a single
;; non-ASCII char when splitting parts by charset.
(= n8bit 1))
'quoted-printable
'base64)))))
(provide 'mm-encode)
;; arch-tag: 7d01bba4-d469-4851-952b-dc863f84ed66
;;; mm-encode.el ends here
|
