;;; mm-encode.el --- Functions for encoding MIME things
-;; Copyright (C) 1998 Free Software Foundation, Inc.
+
+;; 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
+;; 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 2, or (at your option)
-;; any later version.
+;; 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
+;; 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; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
+(eval-when-compile (require 'cl))
(require 'mail-parse)
-(require 'mailcap)
-
-(defvar mm-content-transfer-encoding-defaults
- '(("text/.*" quoted-printable)
+(autoload 'mailcap-extension-to-mime "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.")
+ "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 multipart/mixed headers."
(let ((boundary "=-=-="))
(insert "MIME-Version: 1.0\n")
- (insert (format "Content-Type: multipart/mixed; boundary=\"%s\"\n"
- boundary))
+ (insert "Content-Type: multipart/mixed; boundary=\"" boundary "\"\n")
boundary))
(defun mm-default-file-encoding (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)
- (quoted-printable-encode-region (point-min) (point-max)))
+ ;; 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 (equal type "text/plain")
+ (when (string-match "\\`text/" type)
(goto-char (point-min))
(while (search-forward "\n" nil t)
(replace-match "\r\n" t t)))
- (condition-case ()
- (base64-encode-region (point-min) (point-max))
- (error nil)))
+ (base64-encode-region (point-min) (point-max)))
((memq encoding '(7bit 8bit binary))
+ ;; Do nothing.
)
((null encoding)
+ ;; Do nothing.
)
- ;;((eq encoding 'x-uuencode)
- ;; (condition-case ()
- ;; (uudecode-encode-region (point-min) (point-max))
- ;; (error nil)))
+ ;; Fixme: Ignoring errors here looks bogus.
((functionp encoding)
- (condition-case ()
- (funcall encoding (point-min) (point-max))
- (error nil)))
+ (ignore-errors (funcall encoding (point-min) (point-max))))
(t
- (message "Unknown encoding %s; defaulting to 8bit" encoding))))
+ (error "Unknown encoding %s" encoding))))
-(defun mm-encode-buffer (type)
- "Encode the buffer which contains data of TYPE.
+(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)))
- (encoding
- (or (and (listp type)
- (cadr (assq 'encoding type)))
- (mm-content-transfer-encoding mime-type))))
- (mm-encode-content-transfer-encoding encoding mime-type)
+ (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 "\n"))
(defun mm-content-transfer-encoding (type)
- "Return a CTE suitable for 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 (cadar rules)))
+ (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