;;; mm-encode.el --- Functions for encoding MIME things
-;; Copyright (C) 1998,99 Free Software Foundation, Inc.
+;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004
+;; Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; MORIOKA Tomohiko <morioka@jaist.ac.jp>
;; 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.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Commentary:
;;; Code:
+(eval-when-compile (require 'cl))
(require 'mail-parse)
(require 'mailcap)
+(eval-and-compile
+ (autoload 'mm-body-7-or-8 "mm-bodies")
+ (autoload 'mm-long-lines-p "mm-bodies"))
-(defvar mm-content-transfer-encoding-defaults
- '(("text/.*" quoted-printable)
+(defcustom mm-content-transfer-encoding-defaults
+ '(("text/x-patch" 8bit)
+ ("text/.*" qp-or-base64)
("message/rfc822" 8bit)
- ("application/emacs-lisp" 8bit)
- ("application/x-patch" 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)
+
+(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)
+ "Return an encoding similar to ENCODING but safer than it."
+ (cond
+ ((eq encoding '7bit) '7bit) ;; 7bit is considered safe.
+ ((memq encoding '(8bit quoted-printable)) 'quoted-printable)
+ ;; The remaining encodings are binary and base64 (and perhaps some
+ ;; non-standard ones), which are both turned into base64.
+ (t '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")
(goto-char (point-min))
(while (search-forward "\n" nil t)
(replace-match "\r\n" t t)))
- (condition-case error
- (base64-encode-region (point-min) (point-max))
- (error
- (message "Error while decoding: %s" error)
- nil)))
+ (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
- (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.
+ "Encode the buffer which contains data of MIME type TYPE.
+TYPE is a string or a list of the components.
The encoding used is returned."
(let* ((mime-type (if (stringp type) type (car type)))
(encoding
(bits (mm-body-7-or-8)))
;; We force buffers that are 7bit to be unencoded, no matter
;; what the preferred encoding is.
- (when (eq bits '7bit)
+ ;; Only if the buffers don't contain lone lines.
+ (when (and (eq bits '7bit) (not (mm-long-lines-p 76)))
(setq encoding bits))
(mm-encode-content-transfer-encoding encoding mime-type)
encoding))
(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)
+ 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
projects / gnus / blobdiff