Merge from emacs-23

[gnu-emacs] / lisp / mail / rmailmm.el

;;; rmailmm.el --- MIME decoding and display stuff for RMAIL

;; Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011  Free Software Foundation, Inc.

;; Author: Alexander Pohoyda
;;      Alex Schroeder
;; Maintainer: FSF
;; Keywords: mail
;; Package: rmail

;; 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:

;; Essentially based on the design of Alexander Pohoyda's MIME
;; extensions (mime-display.el and mime.el).

;; This file provides two operation modes for viewing a MIME message.

;; (1) When rmail-enable-mime is non-nil (now it is the default), the
;; function `rmail-show-mime' is automatically called.  That function
;; shows a MIME message directly in RMAIL's view buffer.

;; (2) When rmail-enable-mime is nil, the command 'v' (or M-x
;; rmail-mime) shows a MIME message in a new buffer "*RMAIL*".

;; Both operations share the intermediate functions rmail-mime-process
;; and rmail-mime-process-multipart as below.

;; rmail-show-mime
;;   +- rmail-mime-parse
;;   |    +- rmail-mime-process <--+------------+
;;   |         |         +---------+            |
;;   |         + rmail-mime-process-multipart --+
;;   |
;;   + rmail-mime-insert <----------------+
;;       +- rmail-mime-insert-text        |
;;       +- rmail-mime-insert-bulk        |
;;       +- rmail-mime-insert-multipart --+
;;
;; rmail-mime
;;  +- rmail-mime-show <----------------------------------+
;;       +- rmail-mime-process                            |
;;            +- rmail-mime-handle                        |
;;                 +- rmail-mime-text-handler             |
;;                 +- rmail-mime-bulk-handler             |
;;                 |    + rmail-mime-insert-bulk
;;                 +- rmail-mime-multipart-handler        |
;;                      +- rmail-mime-process-multipart --+

;; In addition, for the case of rmail-enable-mime being non-nil, this
;; file provides two functions rmail-insert-mime-forwarded-message and
;; rmail-insert-mime-resent-message for composing forwarded and resent
;; messages respectively.

;; Todo:

;; Make rmail-mime-media-type-handlers-alist usable in the first
;; operation mode.
;; Handle multipart/alternative in the second operation mode.
;; Offer the option to call external/internal viewers (doc-view, xpdf, etc).

;;; Code:

(require 'rmail)
(require 'mail-parse)
(require 'message)

;;; User options.

(defgroup rmail-mime nil
  "Rmail MIME handling options."
  :prefix "rmail-mime-"
  :group 'rmail)

(defcustom rmail-mime-media-type-handlers-alist
  '(("multipart/.*" rmail-mime-multipart-handler)
    ("text/.*" rmail-mime-text-handler)
    ("text/\\(x-\\)?patch" rmail-mime-bulk-handler)
    ("\\(image\\|audio\\|video\\|application\\)/.*" rmail-mime-bulk-handler))
  "Functions to handle various content types.
This is an alist with elements of the form (REGEXP FUNCTION ...).
The first item is a regular expression matching a content-type.
The remaining elements are handler functions to run, in order of
decreasing preference.  These are called until one returns non-nil.
Note that this only applies to items with an inline Content-Disposition,
all others are handled by `rmail-mime-bulk-handler'.
Note also that this alist is ignored when the variable
`rmail-enable-mime' is non-nil."
  :type '(alist :key-type regexp :value-type (repeat function))
  :version "23.1"
  :group 'rmail-mime)

(defcustom rmail-mime-attachment-dirs-alist
  `(("text/.*" "~/Documents")
    ("image/.*" "~/Pictures")
    (".*" "~/Desktop" "~" ,temporary-file-directory))
  "Default directories to save attachments of various types into.
This is an alist with elements of the form (REGEXP DIR ...).
The first item is a regular expression matching a content-type.
The remaining elements are directories, in order of decreasing preference.
The first directory that exists is used."
  :type '(alist :key-type regexp :value-type (repeat directory))
  :version "23.1"
  :group 'rmail-mime)

(defcustom rmail-mime-show-images 'button
  "What to do with image attachments that Emacs is capable of displaying.
If nil, do nothing special.  If `button', add an extra button
that when pushed displays the image in the buffer.  If a number,
automatically show images if they are smaller than that size (in
bytes), otherwise add a display button.  Anything else means to
automatically display the image in the buffer."
  :type '(choice (const :tag "Add button to view image" button)
                 (const :tag "No special treatment" nil)
                 (number :tag "Show if smaller than certain size")
                 (other :tag "Always show" show))
  :version "23.2"
  :group 'rmail-mime)

;;; End of user options.

;;; Global variables that always have let-binding when referred.

(defvar rmail-mime-mbox-buffer nil
  "Buffer containing the mbox data.
The value is usually nil, and bound to a proper value while
processing MIME.")

(defvar rmail-mime-view-buffer nil
  "Buffer showing a message.
The value is usually nil, and bound to a proper value while
processing MIME.")

(defvar rmail-mime-coding-system nil
  "The first coding-system used for decoding a MIME entity.
The value is usually nil, and bound to non-nil while inserting
MIME entities.")

;;; MIME-entity object

(defun rmail-mime-entity (type disposition transfer-encoding
                               display header tagline body children handler)
  "Retrun a newly created MIME-entity object from arguments.

A MIME-entity is a vector of 9 elements:

  [TYPE DISPOSITION TRANSFER-ENCODING DISPLAY HEADER TAGLINE BODY
   CHILDREN HANDLER]

TYPE and DISPOSITION correspond to MIME headers Content-Type and
Cotent-Disposition respectively, and has this format:

  \(VALUE (ATTRIBUTE . VALUE) (ATTRIBUTE . VALUE) ...)

VALUE is a string and ATTRIBUTE is a symbol.

Consider the following header, for example:

Content-Type: multipart/mixed;
        boundary=\"----=_NextPart_000_0104_01C617E4.BDEC4C40\"

The corresponding TYPE argument must be:

\(\"multipart/mixed\"
  \(\"boundary\" . \"----=_NextPart_000_0104_01C617E4.BDEC4C40\"))

TRANSFER-ENCODING corresponds to MIME header
Content-Transfer-Encoding, and is a lowercased string.

DISPLAY is a vector [CURRENT NEW], where CURRENT indicates how
the header, tagline, and body of the entity are displayed now,
and NEW indicates how their displaying should be updated.
Both elements are vector [HEADER-DISPLAY TAGLINE-DISPLAY BODY-DISPLAY],
where each element is a symbol for the corresponding item that
has these values:
  nil: not displayed
  t: displayed by the decoded presentation form
  raw: displayed by the raw MIME data (for the header and body only)

HEADER and BODY are vectors [BEG END DISPLAY-FLAG], where BEG and
END specify the region of the header or body lines in RMAIL's
data (mbox) buffer, and DISPLAY-FLAG non-nil means that the
header or body is, by default, displayed by the decoded
presentation form.

TAGLINE is a vector [TAG BULK-DATA DISPLAY-FLAG], where TAG is a
string indicating the depth and index number of the entity,
BULK-DATA is a cons (SIZE . TYPE) indicating the size and type of
an attached data, DISPLAY-FLAG non-nil means that the tagline is,
by default, displayed.

CHILDREN is a list of child MIME-entities.  A \"multipart/*\"
entity have one or more children.  A \"message/rfc822\" entity
has just one child.  Any other entity has no child.

HANDLER is a function to insert the entity according to DISPLAY.
It is called with one argument ENTITY."
  (vector type disposition transfer-encoding
          display header tagline body children handler))

;; Accessors for a MIME-entity object.
(defsubst rmail-mime-entity-type (entity) (aref entity 0))
(defsubst rmail-mime-entity-disposition (entity) (aref entity 1))
(defsubst rmail-mime-entity-transfer-encoding (entity) (aref entity 2))
(defsubst rmail-mime-entity-display (entity) (aref entity 3))
(defsubst rmail-mime-entity-header (entity) (aref entity 4))
(defsubst rmail-mime-entity-tagline (entity) (aref entity 5))
(defsubst rmail-mime-entity-body (entity) (aref entity 6))
(defsubst rmail-mime-entity-children (entity) (aref entity 7))
(defsubst rmail-mime-entity-handler (entity) (aref entity 8))

(defsubst rmail-mime-message-p ()
  "Non-nil if and only if the current message is a MIME."
  (or (get-text-property (point) 'rmail-mime-entity)
      (get-text-property (point-min) 'rmail-mime-entity)))

;;; Buttons

(defun rmail-mime-save (button)
  "Save the attachment using info in the BUTTON."
  (let* ((rmail-mime-mbox-buffer rmail-view-buffer)
         (filename (button-get button 'filename))
         (directory (button-get button 'directory))
         (data (button-get button 'data))
         (ofilename filename))
    (setq filename (expand-file-name
                    (read-file-name (format "Save as (default: %s): " filename)
                                    directory
                                    (expand-file-name filename directory))
                    directory))
    ;; If arg is just a directory, use the default file name, but in
    ;; that directory (copied from write-file).
    (if (file-directory-p filename)
        (setq filename (expand-file-name
                        (file-name-nondirectory ofilename)
                        (file-name-as-directory filename))))
    (with-temp-buffer
      (set-buffer-file-coding-system 'no-conversion)
      ;; Needed e.g. by jka-compr, so if the attachment is a compressed
      ;; file, the magic signature compares equal with the unibyte
      ;; signature string recorded in jka-compr-compression-info-list.
      (set-buffer-multibyte nil)
      (setq buffer-undo-list t)
      (if (stringp data)
          (insert data)
        ;; DATA is a MIME-entity object.
        (let ((transfer-encoding (rmail-mime-entity-transfer-encoding data))
              (body (rmail-mime-entity-body data)))
          (insert-buffer-substring rmail-mime-mbox-buffer
                                   (aref body 0) (aref body 1))
          (cond ((string= transfer-encoding "base64")
                 (ignore-errors (base64-decode-region (point-min) (point-max))))
                ((string= transfer-encoding "quoted-printable")
                 (quoted-printable-decode-region (point-min) (point-max))))))
      (write-region nil nil filename nil nil nil t))))

(define-button-type 'rmail-mime-save 'action 'rmail-mime-save)

(defun rmail-mime-entity-segment (pos &optional entity)
  "Return a vector describing the displayed region of a MIME-entity at POS.
Optional 2nd argument ENTITY is the MIME-entity at POS.
The value is a vector [ INDEX HEADER TAGLINE BODY END], where
  HEADER: the position of the beginning of a header
  TAGLINE: the position of the beginning of a tagline
  BODY: the position of the beginning of a body
  END: the position of the end of the entity.
  INDEX: index into the returned vector indicating where POS is."
  (save-excursion
    (or entity
        (setq entity (get-text-property pos 'rmail-mime-entity)))
    (if (not entity)
        (vector 1 (point) (point) (point) (point))
      (let ((current (aref (rmail-mime-entity-display entity) 0))
            (beg (if (and (> pos (point-min))
                          (eq (get-text-property (1- pos) 'rmail-mime-entity)
                              entity))
                     (previous-single-property-change pos 'rmail-mime-entity
                                                      nil (point-min))
                   pos))
            (index 1)
            tagline-beg body-beg end)
        (goto-char beg)
        (if (aref current 0)
            (search-forward "\n\n" nil t))
        (setq tagline-beg (point))
        (if (>= pos tagline-beg)
            (setq index 2))
        (if (aref current 1)
            (forward-line 1))
        (setq body-beg (point))
        (if (>= pos body-beg)
            (setq index 3))
        (if (aref current 2)
            (let ((tag (aref (rmail-mime-entity-tagline entity) 0))
                  tag2)
              (setq end (next-single-property-change beg 'rmail-mime-entity
                                                     nil (point-max)))
              (while (and (< end (point-max))
                          (setq entity (get-text-property end 'rmail-mime-entity)
                                tag2 (aref (rmail-mime-entity-tagline entity) 0))
                          (and (> (length tag2) 0)
                               (eq (string-match tag tag2) 0)))
                (setq end (next-single-property-change end 'rmail-mime-entity
                                                       nil (point-max)))))
          (setq end body-beg))
        (vector index beg tagline-beg body-beg end)))))

(defun rmail-mime-next-item ()
  "Move point to the next displayed item of the current MIME entity.
A MIME entity has three items; header, tagline, and body.
If we are in the last item of the entity, move point to the first
item of the next entity.  If we reach the end of buffer, move
point to the first item of the first entity (i.e. the beginning
of buffer)."
  (interactive)
  (if (rmail-mime-message-p)
      (let* ((segment (rmail-mime-entity-segment (point)))
             (next-pos (aref segment (1+ (aref segment 0))))
             (button (next-button (point))))
        (goto-char (if (and button (< (button-start button) next-pos))
                       (button-start button)
                     next-pos))
        (if (eobp)
            (goto-char (point-min))))))

(defun rmail-mime-previous-item ()
  "Move point to the previous displayed item of the current MIME message.
A MIME entity has three items; header, tagline, and body.
If we are at the beginning of the first item of the entity, move
point to the last item of the previous entity.  If we reach the
beginning of buffer, move point to the last item of the last
entity."
  (interactive)
  (when (rmail-mime-message-p)
    (if (bobp)
        (goto-char (point-max)))
    (let* ((segment (rmail-mime-entity-segment (1- (point))))
           (prev-pos (aref segment (aref segment 0)))
           (button (previous-button (point))))
      (goto-char (if (and button (> (button-start button) prev-pos))
                     (button-start button)
                   prev-pos)))))

(defun rmail-mime-shown-mode (entity)
  "Make MIME-entity ENTITY displayed by the default way."
  (let ((new (aref (rmail-mime-entity-display entity) 1)))
    (aset new 0 (aref (rmail-mime-entity-header entity) 2))
    (aset new 1 (aref (rmail-mime-entity-tagline entity) 2))
    (aset new 2 (aref (rmail-mime-entity-body entity) 2))))

(defun rmail-mime-hidden-mode (entity top)
  "Make MIME-entity ENTITY displayed in the hidden mode.
If TOP is non-nil, display ENTITY only by the tagline.
Otherwise, don't display ENTITY."
  (if top
      (let ((new (aref (rmail-mime-entity-display entity) 1)))
        (aset new 0 nil)
        (aset new 1 top)
        (aset new 2 nil)
        (aset (rmail-mime-entity-body entity) 2 nil))
    (let ((current (aref (rmail-mime-entity-display entity) 0)))
      (aset current 0 nil)
      (aset current 1 nil)
      (aset current 2 nil)))
  (dolist (child (rmail-mime-entity-children entity))
    (rmail-mime-hidden-mode child nil)))

(defun rmail-mime-raw-mode (entity)
  "Make MIME-entity ENTITY displayed in the raw mode."
  (let ((new (aref (rmail-mime-entity-display entity) 1)))
    (aset new 0 'raw)
    (aset new 1 nil)
    (aset new 2 'raw)
    (dolist (child (rmail-mime-entity-children entity))
      (rmail-mime-hidden-mode child nil))))

(defun rmail-mime-toggle-raw (entity)
  "Toggle on and off the raw display mode of MIME-entity ENTITY."
  (let* ((pos (if (eobp) (1- (point-max)) (point)))
         (entity (get-text-property pos 'rmail-mime-entity))
         (current (aref (rmail-mime-entity-display entity) 0))
         (segment (rmail-mime-entity-segment pos entity)))
    (if (not (eq (aref current 0) 'raw))
        ;; Enter the raw mode.
        (rmail-mime-raw-mode entity)
      ;; Enter the shown mode.
      (rmail-mime-shown-mode entity))
    (let ((inhibit-read-only t)
          (modified (buffer-modified-p)))
      (save-excursion
        (goto-char (aref segment 1))
        (rmail-mime-insert entity)
        (restore-buffer-modified-p modified)))))

(defun rmail-mime-toggle-hidden ()
  "Toggle on and off the hidden display mode of MIME-entity ENTITY."
  (interactive)
  (when (rmail-mime-message-p)
    (let* ((rmail-mime-mbox-buffer rmail-view-buffer)
           (rmail-mime-view-buffer (current-buffer))
           (pos (if (eobp) (1- (point-max)) (point)))
           (entity (get-text-property pos 'rmail-mime-entity))
           (current (aref (rmail-mime-entity-display entity) 0))
           (segment (rmail-mime-entity-segment pos entity)))
      (if (aref current 2)
          ;; Enter the hidden mode.
          (progn
            ;; If point is in the body part, move it to the tagline
            ;; (or the header if headline is not displayed).
            (if (= (aref segment 0) 3)
                (goto-char (aref segment 2)))
            (rmail-mime-hidden-mode entity t)
            ;; If the current entity is the topmost one, display the
            ;; header.
            (if (and rmail-mime-mbox-buffer (= (aref segment 1) (point-min)))
                (let ((new (aref (rmail-mime-entity-display entity) 1)))
                  (aset new 0 t))))
        ;; Enter the shown mode.
        (aset (rmail-mime-entity-body entity) 2 t)
        (rmail-mime-shown-mode entity))
      (let ((inhibit-read-only t)
            (modified (buffer-modified-p))
            (rmail-mime-mbox-buffer rmail-view-buffer)
            (rmail-mime-view-buffer rmail-buffer))
        (save-excursion
          (goto-char (aref segment 1))
          (rmail-mime-insert entity)
          (restore-buffer-modified-p modified))))))

(define-key rmail-mode-map "\t" 'rmail-mime-next-item)
(define-key rmail-mode-map [backtab] 'rmail-mime-previous-item)
(define-key rmail-mode-map "\r" 'rmail-mime-toggle-hidden)

;;; Handlers

(defun rmail-mime-insert-tagline (entity &rest item-list)
  "Insert a tag line for MIME-entity ENTITY.
ITEM-LIST is a list of strings or button-elements (list) to be added
to the tag line."
  (insert "[")
  (let ((tag (aref (rmail-mime-entity-tagline entity) 0)))
    (if (> (length tag) 0) (insert (substring tag 1) ":")))
  (insert (car (rmail-mime-entity-type entity)))
  (dolist (item item-list)
    (when item
      (if (stringp item)
          (insert item)
        (apply 'insert-button item))))
  (insert "]\n"))

(defun rmail-mime-insert-header (header)
  "Decode and insert a MIME-entity header HEADER in the current buffer.
HEADER is a vector [BEG END DEFAULT-STATUS].
See `rmail-mime-entity' for the detail."
  (let ((pos (point))
        (last-coding-system-used nil))
    (save-restriction
      (narrow-to-region pos pos)
      (with-current-buffer rmail-mime-mbox-buffer
        (let ((rmail-buffer rmail-mime-mbox-buffer)
              (rmail-view-buffer rmail-mime-view-buffer))
          (save-excursion
            (goto-char (aref header 0))
            (rmail-copy-headers (point) (aref header 1)))))
      (rfc2047-decode-region pos (point))
      (if (and last-coding-system-used (not rmail-mime-coding-system))
          (setq rmail-mime-coding-system last-coding-system-used))
      (goto-char (point-min))
      (rmail-highlight-headers)
      (goto-char (point-max))
      (insert "\n"))))

(defun rmail-mime-text-handler (content-type
                                content-disposition
                                content-transfer-encoding)
  "Handle the current buffer as a plain text MIME part."
  (rmail-mime-insert-text
   (rmail-mime-entity content-type content-disposition
                      content-transfer-encoding
                      (vector (vector nil nil nil) (vector nil nil t))
                      (vector nil nil nil) (vector "" (cons nil nil) t)
                      (vector nil nil nil) nil 'rmail-mime-insert-text))
  t)

(defun rmail-mime-insert-decoded-text (entity)
  "Decode and insert the text body of MIME-entity ENTITY."
  (let* ((content-type (rmail-mime-entity-type entity))
         (charset (cdr (assq 'charset (cdr content-type))))
         (coding-system (if charset
                            (coding-system-from-name charset)))
         (body (rmail-mime-entity-body entity))
         (pos (point)))
    (or (and coding-system (coding-system-p coding-system))
        (setq coding-system 'undecided))
    (if (stringp (aref body 0))
        (insert (aref body 0))
      (let ((transfer-encoding (rmail-mime-entity-transfer-encoding entity)))
        (insert-buffer-substring rmail-mime-mbox-buffer
                                 (aref body 0) (aref body 1))
        (cond ((string= transfer-encoding "base64")
               (ignore-errors (base64-decode-region pos (point))))
              ((string= transfer-encoding "quoted-printable")
               (quoted-printable-decode-region pos (point))))))
    (decode-coding-region pos (point) coding-system)
    (or rmail-mime-coding-system
        (setq rmail-mime-coding-system coding-system))
    (or (bolp) (insert "\n"))))

(defun rmail-mime-insert-text (entity)
  "Presentation handler for a plain text MIME entity."
  (let ((current (aref (rmail-mime-entity-display entity) 0))
        (new (aref (rmail-mime-entity-display entity) 1))
        (header (rmail-mime-entity-header entity))
        (tagline (rmail-mime-entity-tagline entity))
        (body (rmail-mime-entity-body entity))
        (beg (point))
        (segment (rmail-mime-entity-segment (point) entity)))

    (or (integerp (aref body 0))
        (let ((data (buffer-string)))
          (aset body 0 data)
          (delete-region (point-min) (point-max))))

    ;; header
    (if (eq (aref current 0) (aref new 0))
        (goto-char (aref segment 2))
      (if (aref current 0)
          (delete-char (- (aref segment 2) (aref segment 1))))
      (if (aref new 0)
          (rmail-mime-insert-header header)))
    ;; tagline
    (if (eq (aref current 1) (aref new 1))
        (forward-char (- (aref segment 3) (aref segment 2)))
      (if (aref current 1)
          (delete-char (- (aref segment 3) (aref segment 2))))
      (if (aref new 1)
          (rmail-mime-insert-tagline entity)))
    ;; body
    (if (eq (aref current 2) (aref new 2))
        (forward-char (- (aref segment 4) (aref segment 3)))
      (if (aref current 2)
          (delete-char (- (aref segment 4) (aref segment 3))))
      (if (aref new 2)
          (rmail-mime-insert-decoded-text entity)))
    (put-text-property beg (point) 'rmail-mime-entity entity)))

;; FIXME move to the test/ directory?
(defun test-rmail-mime-handler ()
  "Test of a mail using no MIME parts at all."
  (let ((mail "To: alex@gnu.org
Content-Type: text/plain; charset=koi8-r
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0

\372\304\322\301\327\323\324\327\325\312\324\305\41"))
    (switch-to-buffer (get-buffer-create "*test*"))
    (erase-buffer)
    (set-buffer-multibyte nil)
    (insert mail)
    (rmail-mime-show t)
    (set-buffer-multibyte t)))


(defun rmail-mime-insert-image (entity)
  "Decode and insert the image body of MIME-entity ENTITY."
  (let* ((content-type (car (rmail-mime-entity-type entity)))
         (bulk-data (aref (rmail-mime-entity-tagline entity) 1))
         (body (rmail-mime-entity-body entity))
         data)
    (if (stringp (aref body 0))
        (setq data (aref body 0))
      (let ((rmail-mime-mbox-buffer rmail-view-buffer)
            (transfer-encoding (rmail-mime-entity-transfer-encoding entity)))
        (with-temp-buffer
          (set-buffer-multibyte nil)
          (setq buffer-undo-list t)
          (insert-buffer-substring rmail-mime-mbox-buffer
                                   (aref body 0) (aref body 1))
          (cond ((string= transfer-encoding "base64")
                 (ignore-errors (base64-decode-region (point-min) (point-max))))
                ((string= transfer-encoding "quoted-printable")
                 (quoted-printable-decode-region (point-min) (point-max))))
          (setq data
                (buffer-substring-no-properties (point-min) (point-max))))))
    (insert-image (create-image data (cdr bulk-data) t))
    (insert "\n")))

(defun rmail-mime-image (button)
  "Display the image associated with BUTTON."
  (save-excursion
    (goto-char (button-end button))
    (rmail-mime-toggle-hidden)))

(define-button-type 'rmail-mime-image 'action 'rmail-mime-image)


(defun rmail-mime-bulk-handler (content-type
                                content-disposition
                                content-transfer-encoding)
  "Handle the current buffer as an attachment to download.
For images that Emacs is capable of displaying, the behavior
depends upon the value of `rmail-mime-show-images'."
  (rmail-mime-insert-bulk
   (rmail-mime-entity content-type content-disposition content-transfer-encoding
                      (vector (vector nil nil nil) (vector nil t nil))
                      (vector nil nil nil) (vector "" (cons nil nil) t)
                      (vector nil nil nil) nil 'rmail-mime-insert-bulk)))

(defun rmail-mime-set-bulk-data (entity)
  "Setup the information about the attachment object for MIME-entity ENTITY.
The value is non-nil if and only if the attachment object should be shown
directly."
  (let ((content-type (car (rmail-mime-entity-type entity)))
        (size (cdr (assq 'size (cdr (rmail-mime-entity-disposition entity)))))
        (bulk-data (aref (rmail-mime-entity-tagline entity) 1))
        (body (rmail-mime-entity-body entity))
        size type to-show)
    (cond (size
           (setq size (string-to-number size)))
          ((stringp (aref body 0))
           (setq size (length (aref body 0))))
          (t
           ;; Rough estimation of the size.
           (let ((encoding (rmail-mime-entity-transfer-encoding entity)))
             (setq size (- (aref body 1) (aref body 0)))
             (cond ((string= encoding "base64")
                    (setq size (/ (* size 3) 4)))
                   ((string= encoding "quoted-printable")
                    (setq size (/ (* size 7) 3)))))))

    (cond
     ((string-match "text/" content-type)
      (setq type 'text))
     ((string-match "image/\\(.*\\)" content-type)
      (setq type (image-type-from-file-name
                  (concat "." (match-string 1 content-type))))
      (if (and (memq type image-types)
               (image-type-available-p type))
          (if (and rmail-mime-show-images
                   (not (eq rmail-mime-show-images 'button))
                   (or (not (numberp rmail-mime-show-images))
                       (< size rmail-mime-show-images)))
              (setq to-show t))
        (setq type nil))))
    (setcar bulk-data size)
    (setcdr bulk-data type)
    to-show))

(defun rmail-mime-insert-bulk (entity)
  "Presentation handler for an attachment MIME entity."
  ;; Find the default directory for this media type.
  (let* ((content-type (rmail-mime-entity-type entity))
         (content-disposition (rmail-mime-entity-disposition entity))
         (current (aref (rmail-mime-entity-display entity) 0))
         (new (aref (rmail-mime-entity-display entity) 1))
         (header (rmail-mime-entity-header entity))
         (tagline (rmail-mime-entity-tagline entity))
         (bulk-data (aref tagline 1))
         (body (rmail-mime-entity-body entity))
         (directory (catch 'directory
                      (dolist (entry rmail-mime-attachment-dirs-alist)
                        (when (string-match (car entry) (car content-type))
                          (dolist (dir (cdr entry))
                            (when (file-directory-p dir)
                              (throw 'directory dir)))))))
         (filename (or (cdr (assq 'name (cdr content-type)))
                       (cdr (assq 'filename (cdr content-disposition)))
                       "noname"))
         (units '(B kB MB GB))
         (segment (rmail-mime-entity-segment (point) entity))
         beg data size)

    (if (integerp (aref body 0))
        (setq data entity
              size (car bulk-data))
      (if (stringp (aref body 0))
          (setq data (aref body 0))
        (setq data (string-as-unibyte (buffer-string)))
        (aset body 0 data)
        (rmail-mime-set-bulk-data entity)
        (delete-region (point-min) (point-max)))
      (setq size (length data)))
    (while (and (> size 1024.0) ; cribbed from gnus-agent-expire-done-message
                (cdr units))
      (setq size (/ size 1024.0)
            units (cdr units)))

    (setq beg (point))

    ;; header
    (if (eq (aref current 0) (aref new 0))
        (goto-char (aref segment 2))
      (if (aref current 0)
          (delete-char (- (aref segment 2) (aref segment 1))))
      (if (aref new 0)
          (rmail-mime-insert-header header)))

    ;; tagline
    (if (eq (aref current 1) (aref new 1))
        (forward-char (- (aref segment 3) (aref segment 2)))
      (if (aref current 1)
          (delete-char (- (aref segment 3) (aref segment 2))))
      (if (aref new 1)
          (rmail-mime-insert-tagline
           entity
           " file:"
           (list filename
                 :type 'rmail-mime-save
                 'help-echo "mouse-2, RET: Save attachment"
                 'filename filename
                 'directory (file-name-as-directory directory)
                 'data data)
           (format " (%.0f%s)" size (car units))
           (if (cdr bulk-data)
               " ")
           (if (cdr bulk-data)
               (list "Toggle show/hide"
                     :type 'rmail-mime-image
                     'help-echo "mouse-2, RET: Toggle show/hide"
                     'image-type (cdr bulk-data)
                     'image-data data)))))
    ;; body
    (if (eq (aref current 2) (aref new 2))
        (forward-char (- (aref segment 4) (aref segment 3)))
      (if (aref current 2)
          (delete-char (- (aref segment 4) (aref segment 3))))
      (if (aref new 2)
          (cond ((eq (cdr bulk-data) 'text)
                 (rmail-mime-insert-decoded-text entity))
                ((cdr bulk-data)
                 (rmail-mime-insert-image entity)))))
    (put-text-property beg (point) 'rmail-mime-entity entity)))

(defun test-rmail-mime-bulk-handler ()
  "Test of a mail used as an example in RFC 2183."
  (let ((mail "Content-Type: image/jpeg
Content-Disposition: attachment; filename=genome.jpeg;
  modification-date=\"Wed, 12 Feb 1997 16:29:51 -0500\";
Content-Description: a complete map of the human genome
Content-Transfer-Encoding: base64

iVBORw0KGgoAAAANSUhEUgAAADAAAAAwCAMAAABg3Am1AAAABGdBTUEAALGPC/xhBQAAAAZQ
TFRF////AAAAVcLTfgAAAPZJREFUeNq9ldsOwzAIQ+3//+l1WlvA5ZLsoUiTto4TB+ISoAjy
+ITfRBfcAmgRFFeAm+J6uhdKdFhFWUgDkFsK0oUp/9G2//Kj7Jx+5tSKOdBscgUYiKHRS/me
WATQdRUvAK0Bnmshmtn79PpaLBbbOZkjKvRnjRZoRswOkG1wFchKew2g9wXVJVZL/m4+B+vv
9AxQQR2Q33SgAYJzzVACdAWjAfRYzYFO9n6SLnydtQHSMxYDMAKqZ/8FS/lTK+zuq3CtK64L
UDwbgUEAUmk2Zyg101d6PhCDySgAvTvDgKiuOrc4dLxUb7UMnhGIexyI+d6U+ABuNAP4Simx
lgAAAABJRU5ErkJggg==
"))
    (switch-to-buffer (get-buffer-create "*test*"))
    (erase-buffer)
    (insert mail)
    (rmail-mime-show)))

(defun rmail-mime-multipart-handler (content-type
                                     content-disposition
                                     content-transfer-encoding)
  "Handle the current buffer as a multipart MIME body.
The current buffer should be narrowed to the body.  CONTENT-TYPE,
CONTENT-DISPOSITION, and CONTENT-TRANSFER-ENCODING are the values
of the respective parsed headers.  See `rmail-mime-handle' for their
format."
  (rmail-mime-process-multipart
   content-type content-disposition content-transfer-encoding nil)
  t)

(defun rmail-mime-process-multipart (content-type
                                     content-disposition
                                     content-transfer-encoding
                                     parse-tag)
  "Process the current buffer as a multipart MIME body.

If PARSE-TAG is nil, modify the current buffer directly for
showing the MIME body and return nil.

Otherwise, PARSE-TAG is a string indicating the depth and index
number of the entity.  In this case, parse the current buffer and
return a list of MIME-entity objects.

The other arguments are the same as `rmail-mime-multipart-handler'."
  ;; Some MUAs start boundaries with "--", while it should start
  ;; with "CRLF--", as defined by RFC 2046:
  ;;    The boundary delimiter MUST occur at the beginning of a line,
  ;;    i.e., following a CRLF, and the initial CRLF is considered to
  ;;    be attached to the boundary delimiter line rather than part
  ;;    of the preceding part.
  ;; We currently don't handle that.
  (let ((boundary (cdr (assq 'boundary content-type)))
        (subtype (cadr (split-string (car content-type) "/")))
        (index 0)
        beg end next entities)
    (unless boundary
      (rmail-mm-get-boundary-error-message
       "No boundary defined" content-type content-disposition
       content-transfer-encoding))
    (setq boundary (concat "\n--" boundary))
    ;; Hide the body before the first bodypart
    (goto-char (point-min))
    (when (and (search-forward boundary nil t)
               (looking-at "[ \t]*\n"))
      (if parse-tag
          (narrow-to-region (match-end 0) (point-max))
        (delete-region (point-min) (match-end 0))))

    ;; Change content-type to the proper default one for the children.
    (cond ((string-match "mixed" subtype)
           (setq content-type '("text/plain")))
          ((string-match "digest" subtype)
           (setq content-type '("message/rfc822"))))

    ;; Loop over all body parts, where beg points at the beginning of
    ;; the part and end points at the end of the part.  next points at
    ;; the beginning of the next part.  The current point is just
    ;; after the boundary tag.
    (setq beg (point-min))
    (while (search-forward boundary nil t)
      (setq end (match-beginning 0))
      ;; If this is the last boundary according to RFC 2046, hide the
      ;; epilogue, else hide the boundary only.  Use a marker for
      ;; `next' because `rmail-mime-show' may change the buffer.
      (cond ((looking-at "--[ \t]*$")
             (setq next (point-max-marker)))
            ((looking-at "[ \t]*\n")
             (setq next (copy-marker (match-end 0) t)))
            (t
             (rmail-mm-get-boundary-error-message
              "Malformed boundary" content-type content-disposition
              content-transfer-encoding)))

      (setq index (1+ index))
      ;; Handle the part.
      (if parse-tag
          (save-restriction
            (narrow-to-region beg end)
            (let ((child (rmail-mime-process
                          nil (format "%s/%d" parse-tag index)
                          content-type content-disposition)))
              ;; Display a tagline.
              (aset (aref (rmail-mime-entity-display child) 1) 1
                    (aset (rmail-mime-entity-tagline child) 2 t))
              (push child entities)))

        (delete-region end next)
        (save-restriction
          (narrow-to-region beg end)
          (rmail-mime-show)))
      (goto-char (setq beg next)))

    (when parse-tag
      (setq entities (nreverse entities))
      (if (string-match "alternative" subtype)
          ;; Find the best entity to show, and hide all the others.
          (let (best second)
            (dolist (child entities)
              (if (string= (or (car (rmail-mime-entity-disposition child))
                               (car content-disposition))
                           "inline")
                  (if (string-match "text/plain"
                                    (car (rmail-mime-entity-type child)))
                      (setq best child)
                    (if (string-match "text/.*"
                                      (car (rmail-mime-entity-type child)))
                        (setq second child)))))
            (or best (not second) (setq best second))
            (dolist (child entities)
              (or (eq best child)
                  (rmail-mime-hidden-mode child t)))))
      entities)))

(defun test-rmail-mime-multipart-handler ()
  "Test of a mail used as an example in RFC 2046."
  (let ((mail "From: Nathaniel Borenstein <nsb@bellcore.com>
To: Ned Freed <ned@innosoft.com>
Date: Sun, 21 Mar 1993 23:56:48 -0800 (PST)
Subject: Sample message
MIME-Version: 1.0
Content-type: multipart/mixed; boundary=\"simple boundary\"

This is the preamble.  It is to be ignored, though it
is a handy place for composition agents to include an
explanatory note to non-MIME conformant readers.

--simple boundary

This is implicitly typed plain US-ASCII text.
It does NOT end with a linebreak.
--simple boundary
Content-type: text/plain; charset=us-ascii

This is explicitly typed plain US-ASCII text.
It DOES end with a linebreak.

--simple boundary--

This is the epilogue.  It is also to be ignored."))
    (switch-to-buffer (get-buffer-create "*test*"))
    (erase-buffer)
    (insert mail)
    (rmail-mime-show t)))

(defun rmail-mime-insert-multipart (entity)
  "Presentation handler for a multipart MIME entity."
  (let ((current (aref (rmail-mime-entity-display entity) 0))
        (new (aref (rmail-mime-entity-display entity) 1))
        (header (rmail-mime-entity-header entity))
        (tagline (rmail-mime-entity-tagline entity))
        (body (rmail-mime-entity-body entity))
        (beg (point))
        (segment (rmail-mime-entity-segment (point) entity)))
    ;; header
    (if (eq (aref current 0) (aref new 0))
        (goto-char (aref segment 2))
      (if (aref current 0)
          (delete-char (- (aref segment 2) (aref segment 1))))
      (if (aref new 0)
          (rmail-mime-insert-header header)))
    ;; tagline
    (if (eq (aref current 1) (aref new 1))
        (forward-char (- (aref segment 3) (aref segment 2)))
      (if (aref current 1)
          (delete-char (- (aref segment 3) (aref segment 2))))
      (if (aref new 1)
          (rmail-mime-insert-tagline entity)))

    (put-text-property beg (point) 'rmail-mime-entity entity)
    ;; body
    (if (eq (aref current 2) (aref new 2))
        (forward-char (- (aref segment 4) (aref segment 3)))
      (if (aref current 2)
          (delete-char (- (aref segment 4) (aref segment 3))))
      (if (aref new 2)
          (dolist (child (rmail-mime-entity-children entity))
            (rmail-mime-insert child))))))

;;; Main code

(defun rmail-mime-handle (content-type
                          content-disposition
                          content-transfer-encoding)
  "Handle the current buffer as a MIME part.
The current buffer should be narrowed to the respective body, and
point should be at the beginning of the body.

CONTENT-TYPE, CONTENT-DISPOSITION, and CONTENT-TRANSFER-ENCODING
are the values of the respective parsed headers.  The latter should
be downcased.  The parsed headers for CONTENT-TYPE and CONTENT-DISPOSITION
have the form

  \(VALUE . ALIST)

In other words:

  \(VALUE (ATTRIBUTE . VALUE) (ATTRIBUTE . VALUE) ...)

VALUE is a string and ATTRIBUTE is a symbol.

Consider the following header, for example:

Content-Type: multipart/mixed;
        boundary=\"----=_NextPart_000_0104_01C617E4.BDEC4C40\"

The parsed header value:

\(\"multipart/mixed\"
  \(\"boundary\" . \"----=_NextPart_000_0104_01C617E4.BDEC4C40\"))"
  ;; Handle the content transfer encodings we know.  Unknown transfer
  ;; encodings will be passed on to the various handlers.
  (cond ((string= content-transfer-encoding "base64")
         (when (ignore-errors
                 (base64-decode-region (point) (point-max)))
           (setq content-transfer-encoding nil)))
        ((string= content-transfer-encoding "quoted-printable")
         (quoted-printable-decode-region (point) (point-max))
         (setq content-transfer-encoding nil))
        ((string= content-transfer-encoding "8bit")
         ;; FIXME: Is this the correct way?
         ;; No, of course not, it just means there's no decoding to do.
         ;; (set-buffer-multibyte nil)
         (setq content-transfer-encoding nil)
         ))
  ;; Inline stuff requires work.  Attachments are handled by the bulk
  ;; handler.
  (if (string= "inline" (car content-disposition))
      (let ((stop nil))
        (dolist (entry rmail-mime-media-type-handlers-alist)
          (when (and (string-match (car entry) (car content-type)) (not stop))
            (progn
              (setq stop (funcall (cadr entry) content-type
                                  content-disposition
                                  content-transfer-encoding))))))
    ;; Everything else is an attachment.
    (rmail-mime-bulk-handler content-type
                       content-disposition
                       content-transfer-encoding)))

(defun rmail-mime-show (&optional show-headers)
  "Handle the current buffer as a MIME message.
If SHOW-HEADERS is non-nil, then the headers of the current part
will shown as usual for a MIME message.  The headers are also
shown for the content type message/rfc822.  This function will be
called recursively if multiple parts are available.

The current buffer must contain a single message.  It will be
modified."
  (rmail-mime-process show-headers nil))

(defun rmail-mime-process (show-headers parse-tag &optional
                                        default-content-type
                                        default-content-disposition)
  (let ((end (point-min))
        content-type
        content-transfer-encoding
        content-disposition)
    ;; `point-min' returns the beginning and `end' points at the end
    ;; of the headers.
    (goto-char (point-min))
    ;; If we're showing a part without headers, then it will start
    ;; with a newline.
    (if (eq (char-after) ?\n)
        (setq end (1+ (point)))
      (when (search-forward "\n\n" nil t)
        (setq end (match-end 0))
        (save-restriction
          (narrow-to-region (point-min) end)
          ;; FIXME: Default disposition of the multipart entities should
          ;; be inherited.
          (setq content-type
                (mail-fetch-field "Content-Type")
                content-transfer-encoding
                (mail-fetch-field "Content-Transfer-Encoding")
                content-disposition
                (mail-fetch-field "Content-Disposition")))))
    ;; Per RFC 2045, C-T-E is case insensitive (bug#5070), but the others
    ;; are not completely so.  Hopefully mail-header-parse-* DTRT.
    (if content-transfer-encoding
        (setq content-transfer-encoding (downcase content-transfer-encoding)))
    (setq content-type
          (if content-type
              (mail-header-parse-content-type content-type)
            (or default-content-type '("text/plain"))))
    (setq content-disposition
          (if content-disposition
              (mail-header-parse-content-disposition content-disposition)
            ;; If none specified, we are free to choose what we deem
            ;; suitable according to RFC 2183.  We like inline.
            (or default-content-disposition '("inline"))))
    ;; Unrecognized disposition types are to be treated like
    ;; attachment according to RFC 2183.
    (unless (member (car content-disposition) '("inline" "attachment"))
      (setq content-disposition '("attachment")))

    (if parse-tag
        (let* ((is-inline (string= (car content-disposition) "inline"))
               (header (vector (point-min) end nil))
               (tagline (vector parse-tag (cons nil nil) t))
               (body (vector end (point-max) is-inline))
               (new (vector (aref header 2) (aref tagline 2) (aref body 2)))
               children handler entity)
          (cond ((string-match "multipart/.*" (car content-type))
                 (save-restriction
                   (narrow-to-region (1- end) (point-max))
                   (setq children (rmail-mime-process-multipart
                                   content-type
                                   content-disposition
                                   content-transfer-encoding
                                   parse-tag)
                         handler 'rmail-mime-insert-multipart)))
                ((string-match "message/rfc822" (car content-type))
                 (save-restriction
                   (narrow-to-region end (point-max))
                   (let* ((msg (rmail-mime-process t parse-tag
                                                   '("text/plain") '("inline")))
                          (msg-new (aref (rmail-mime-entity-display msg) 1)))
                     ;; Show header of the child.
                     (aset msg-new 0 t)
                     (aset (rmail-mime-entity-header msg) 2 t)
                     ;; Hide tagline of the child.
                     (aset msg-new 1 nil)
                     (aset (rmail-mime-entity-tagline msg) 2 nil)
                     (setq children (list msg)
                           handler 'rmail-mime-insert-multipart))))
                ((and is-inline (string-match "text/" (car content-type)))
                 ;; Don't need a tagline.
                 (aset new 1 (aset tagline 2 nil))
                 (setq handler 'rmail-mime-insert-text))
                (t
                 ;; Force hidden mode.
                 (aset new 1 (aset tagline 2 t))
                 (aset new 2 (aset body 2 nil))
                 (setq handler 'rmail-mime-insert-bulk)))
          (setq entity (rmail-mime-entity content-type
                                          content-disposition
                                          content-transfer-encoding
                                          (vector (vector nil nil nil) new)
                                          header tagline body children handler))
          (if (and (eq handler 'rmail-mime-insert-bulk)
                   (rmail-mime-set-bulk-data entity))
              ;; Show the body.
              (aset new 2 (aset body 2 t)))
          entity)

      ;; Hide headers and handle the part.
      (put-text-property (point-min) (point-max) 'rmail-mime-entity
                         (rmail-mime-entity
                         content-type content-disposition
                         content-transfer-encoding
                         (vector (vector 'raw nil 'raw) (vector 'raw nil 'raw))
                         (vector nil nil 'raw) (vector "" (cons nil nil) nil)
                         (vector nil nil 'raw) nil nil))
      (save-restriction
        (cond ((string= (car content-type) "message/rfc822")
               (narrow-to-region end (point-max)))
              ((not show-headers)
               (delete-region (point-min) end)))
        (rmail-mime-handle content-type content-disposition
                           content-transfer-encoding)))))

(defun rmail-mime-parse ()
  "Parse the current Rmail message as a MIME message.
The value is a MIME-entiy object (see `rmail-mime-entity').
If an error occurs, return an error message string."
  (let ((rmail-mime-mbox-buffer (if (rmail-buffers-swapped-p)
                                    rmail-view-buffer
                                  (current-buffer))))
    (condition-case err
        (with-current-buffer rmail-mime-mbox-buffer
          (save-excursion
            (goto-char (point-min))
            (let* ((entity (rmail-mime-process t ""
                                               '("text/plain") '("inline")))
                   (new (aref (rmail-mime-entity-display entity) 1)))
              ;; Show header.
              (aset new 0 (aset (rmail-mime-entity-header entity) 2 t))
              ;; Show tagline if and only if body is not shown.
              (if (aref new 2)
                  (aset new 1 (aset (rmail-mime-entity-tagline entity) 2 nil))
                (aset new 1 (aset (rmail-mime-entity-tagline entity) 2 t)))
              entity)))
      (error (format "%s" err)))))

(defun rmail-mime-insert (entity)
  "Insert a MIME-entity ENTITY in the current buffer.

This function will be called recursively if multiple parts are
available."
  (let ((current (aref (rmail-mime-entity-display entity) 0))
        (new (aref (rmail-mime-entity-display entity) 1)))
    (if (not (eq (aref new 0) 'raw))
        ;; Not a raw-mode.  Each handler should handle it.
        (funcall (rmail-mime-entity-handler entity) entity)
      (let ((header (rmail-mime-entity-header entity))
            (tagline (rmail-mime-entity-tagline entity))
            (body (rmail-mime-entity-body entity))
            (beg (point))
            (segment (rmail-mime-entity-segment (point) entity)))
        ;; header
        (if (eq (aref current 0) (aref new 0))
            (goto-char (aref segment 2))
          (if (aref current 0)
              (delete-char (- (aref segment 2) (aref segment 1))))
          (insert-buffer-substring rmail-mime-mbox-buffer
                                     (aref header 0) (aref header 1)))
        ;; tagline
        (if (aref current 1)
            (delete-char (- (aref segment 3) (aref segment 2))))
        ;; body
        (if (eq (aref current 2) (aref new 2))
            (forward-char (- (aref segment 4) (aref segment 3)))
          (if (aref current 2)
              (delete-char (- (aref segment 4) (aref segment 3))))
          (insert-buffer-substring rmail-mime-mbox-buffer
                                   (aref body 0) (aref body 1)))
        (put-text-property beg (point) 'rmail-mime-entity entity)))
    (dotimes (i 3)
      (aset current i (aref new i)))))

(define-derived-mode rmail-mime-mode fundamental-mode "RMIME"
  "Major mode used in `rmail-mime' buffers."
  (setq font-lock-defaults '(rmail-font-lock-keywords t t nil nil)))

;;;###autoload
(defun rmail-mime (&optional arg)
  "Toggle displaying of a MIME message.

The actualy behavior depends on the value of `rmail-enable-mime'.

If `rmail-enable-mime' is t (default), this command change the
displaying of a MIME message between decoded presentation form
and raw data.

With ARG, toggle the displaying of the current MIME entity only.

If `rmail-enable-mime' is nil, this creates a temporary
\"*RMAIL*\" buffer holding a decoded copy of the message.  Inline
content-types are handled according to
`rmail-mime-media-type-handlers-alist'.  By default, this
displays text and multipart messages, and offers to download
attachments as specfied by `rmail-mime-attachment-dirs-alist'."
  (interactive "P")
  (if rmail-enable-mime
      (if (rmail-mime-message-p)
          (let ((rmail-mime-mbox-buffer rmail-view-buffer)
                (rmail-mime-view-buffer rmail-buffer)
                (entity (get-text-property (point) 'rmail-mime-entity)))
            (if arg
                (if entity
                    (rmail-mime-toggle-raw entity))
              (goto-char (point-min))
              (rmail-mime-toggle-raw
               (get-text-property (point) 'rmail-mime-entity))))
        (message "Not a MIME message"))
    (let* ((data (rmail-apply-in-message rmail-current-message 'buffer-string))
           (buf (get-buffer-create "*RMAIL*"))
           (rmail-mime-mbox-buffer rmail-view-buffer)
           (rmail-mime-view-buffer buf))
      (set-buffer buf)
      (setq buffer-undo-list t)
      (let ((inhibit-read-only t))
        ;; Decoding the message in fundamental mode for speed, only
        ;; switching to rmail-mime-mode at the end for display.  Eg
        ;; quoted-printable-decode-region gets very slow otherwise (Bug#4993).
        (fundamental-mode)
        (erase-buffer)
        (insert data)
        (rmail-mime-show t)
        (rmail-mime-mode)
        (set-buffer-modified-p nil))
      (view-buffer buf))))

(defun rmail-mm-get-boundary-error-message (message type disposition encoding)
  "Return MESSAGE with more information on the main mime components."
  (error "%s; type: %s; disposition: %s; encoding: %s"
         message type disposition encoding))

(defun rmail-show-mime ()
  "Function to set in `rmail-show-mime-function' (which see)."
  (let ((entity (rmail-mime-parse))
        (rmail-mime-mbox-buffer rmail-buffer)
        (rmail-mime-view-buffer rmail-view-buffer)
        (rmail-mime-coding-system nil))
    (if (vectorp entity)
        (with-current-buffer rmail-mime-view-buffer
          (erase-buffer)
          (rmail-mime-insert entity)
          (if rmail-mime-coding-system
              (set-buffer-file-coding-system rmail-mime-coding-system t t)))
      ;; Decoding failed.  ENTITY is an error message.  Insert the
      ;; original message body as is, and show warning.
      (let ((region (with-current-buffer rmail-mime-mbox-buffer
                      (goto-char (point-min))
                      (re-search-forward "^$" nil t)
                      (forward-line 1)
                      (vector (point-min) (point) (point-max)))))
        (with-current-buffer rmail-mime-view-buffer
          (let ((inhibit-read-only t))
            (erase-buffer)
            (rmail-mime-insert-header region)
            (insert-buffer-substring rmail-mime-mbox-buffer
                                     (aref region 1) (aref region 2))))
        (set-buffer-file-coding-system 'no-conversion t t)
        (message "MIME decoding failed: %s" entity)))))

(setq rmail-show-mime-function 'rmail-show-mime)

(defun rmail-insert-mime-forwarded-message (forward-buffer)
  "Function to set in `rmail-insert-mime-forwarded-message-function' (which see)."
  (let ((rmail-mime-mbox-buffer
         (with-current-buffer forward-buffer rmail-view-buffer)))
    (save-restriction
      (narrow-to-region (point) (point))
      (message-forward-make-body-mime rmail-mime-mbox-buffer))))

(setq rmail-insert-mime-forwarded-message-function
      'rmail-insert-mime-forwarded-message)

(defun rmail-insert-mime-resent-message (forward-buffer)
  "Function to set in `rmail-insert-mime-resent-message-function' (which see)."
  (insert-buffer-substring
   (with-current-buffer forward-buffer rmail-view-buffer))
  (goto-char (point-min))
  (when (looking-at "From ")
    (forward-line 1)
    (delete-region (point-min) (point))))

(setq rmail-insert-mime-resent-message-function
      'rmail-insert-mime-resent-message)

(defun rmail-search-mime-message (msg regexp)
  "Function to set in `rmail-search-mime-message-function' (which see)."
  (save-restriction
    (narrow-to-region (rmail-msgbeg msg) (rmail-msgend msg))
    (let* ((rmail-mime-mbox-buffer (current-buffer))
           (rmail-mime-view-buffer rmail-view-buffer)
           (header-end (save-excursion
                         (re-search-forward "^$" nil 'move) (point)))
           (body-end (point-max))
           (entity (rmail-mime-parse)))
      (or
       ;; At first, just search the headers.
       (with-temp-buffer
         (insert-buffer-substring rmail-mime-mbox-buffer nil header-end)
         (rfc2047-decode-region (point-min) (point))
         (goto-char (point-min))
         (re-search-forward regexp nil t))
       ;; Next, search the body.
       (if (and entity
                (let* ((content-type (rmail-mime-entity-type entity))
                       (charset (cdr (assq 'charset (cdr content-type)))))
                  (or (not (string-match "text/.*" (car content-type)))
                      (and charset
                           (not (string= (downcase charset) "us-ascii"))))))
           ;; Search the decoded MIME message.
           (with-temp-buffer
             (rmail-mime-insert entity)
             (goto-char (point-min))
             (re-search-forward regexp nil t))
         ;; Search the body without decoding.
         (goto-char header-end)
         (re-search-forward regexp nil t))))))

(setq rmail-search-mime-message-function 'rmail-search-mime-message)

(provide 'rmailmm)

;; Local Variables:
;; generated-autoload-file: "rmail.el"
;; End:

;; arch-tag: 3f2c5e5d-1aef-4512-bc20-fd737c9d5dd9
;;; rmailmm.el ends here