2002-01-24 Katsumi Yamaoka <yamaoka@jpl.org>
[gnus] / lisp / mm-decode.el
index 421b701..2181905 100644 (file)
 
 ;;; Commentary:
 
-;; Jaap-Henk Hoepman (jhh@xs4all.nl): 
-;;
-;; Added support for delayed destroy of external MIME viewers. All external
-;; viewers for mime types in mm-keep-viewer-alive-types will remain active
-;; after switching articles or groups, and will only be removed when exiting
-;; gnus.
-;; 
-
 ;;; Code:
 
 (require 'mail-parse)
 (require 'mailcap)
 (require 'mm-bodies)
-(eval-when-compile (require 'cl))
+(eval-when-compile (require 'cl)
+                  (require 'term))
 
 (eval-and-compile
   (autoload 'mm-inline-partial "mm-partial")
   `(list ,buffer ,type ,encoding ,undisplayer
         ,disposition ,description ,cache ,id))
 
+(defcustom mm-inline-text-html-renderer
+  (cond ((locate-library "w3")
+        'mm-inline-text-html-render-with-w3)
+       ((locate-library "w3m")
+        'mm-inline-text-html-render-with-w3m))
+  "Function used for rendering HTML contents.  The function will be
+called with a MIME handle as the argument.  There are two pre-defined
+functions: `mm-inline-text-html-render-with-w3', which uses Emacs/w3;
+and `mm-inline-text-html-render-with-w3m', which uses emacs-w3m."
+  :type '(radio (function-item mm-inline-text-html-render-with-w3)
+               (function-item mm-inline-text-html-render-with-w3m)
+               (function))
+  :group 'mime-display)
+
 (defcustom mm-inline-media-tests
   '(("image/jpeg"
      mm-inline-image
      (lambda (handle)
        (locate-library "diff-mode")))
     ("application/emacs-lisp" mm-display-elisp-inline identity)
+    ("application/x-emacs-lisp" mm-display-elisp-inline identity)
     ("text/html"
      mm-inline-text
      (lambda (handle)
-       (locate-library "w3")))
+       (gnus-functionp mm-inline-text-html-renderer)))
     ("text/x-vcard"
      mm-inline-text
      (lambda (handle)
     ("application/pgp-signature" ignore identity)
     ("application/x-pkcs7-signature" ignore identity)
     ("application/pkcs7-signature" ignore identity)
+    ("application/x-pkcs7-mime" ignore identity)
+    ("application/pkcs7-mime" ignore identity)
     ("multipart/alternative" ignore identity)
     ("multipart/mixed" ignore identity)
-    ("multipart/related" ignore identity))
+    ("multipart/related" ignore identity)
+    ;; Disable audio and image
+    ("audio/.*" ignore ignore)
+    ("image/.*" ignore ignore)
+    ;; Default to displaying as text
+    (".*" mm-inline-text mm-readable-p))
   "Alist of media types/tests saying whether types can be displayed inline."
   :type '(repeat (list (string :tag "MIME type")
                       (function :tag "Display function")
   '("image/.*" "text/.*" "message/delivery-status" "message/rfc822"
     "message/partial" "message/external-body" "application/emacs-lisp"
     "application/pgp-signature" "application/x-pkcs7-signature"
-    "application/pkcs7-signature")
-  "List of media types that are to be displayed inline."
+    "application/pkcs7-signature" "application/x-pkcs7-mime"
+    "application/pkcs7-mime")
+  "List of media types that are to be displayed inline.
+See also `mm-inline-media-tests', which says how to display a media
+type inline."
   :type '(repeat string)
   :group 'mime-display)
 
 when selecting a different article."
   :type '(repeat string)
   :group 'mime-display)
+
 (defcustom mm-automatic-display
   '("text/plain" "text/enriched" "text/richtext" "text/html"
     "text/x-vcard" "image/.*" "message/delivery-status" "multipart/.*"
     "message/rfc822" "text/x-patch" "application/pgp-signature"
     "application/emacs-lisp" "application/x-pkcs7-signature"
-    "application/pkcs7-signature")
+    "application/pkcs7-signature" "application/x-pkcs7-mime"
+    "application/pkcs7-mime")
   "A list of MIME types to be displayed automatically."
   :type '(repeat string)
   :group 'mime-display)
 
-(defcustom mm-attachment-override-types '("text/x-vcard")
+(defcustom mm-attachment-override-types '("text/x-vcard"
+                                         "application/pkcs7-mime"
+                                         "application/x-pkcs7-mime"
+                                         "application/pkcs7-signature"
+                                         "application/x-pkcs7-signature")
   "Types to have \"attachment\" ignored if they can be displayed inline."
   :type '(repeat string)
   :group 'mime-display)
@@ -253,10 +276,38 @@ to:
   :type 'boolean
   :group 'mime-display)
 
+(defvar mm-file-name-rewrite-functions nil
+  "*List of functions used for rewriting file names of MIME parts.
+Each function takes a file name as input and returns a file name.
+
+Ready-made functions include
+`mm-file-name-delete-whitespace',
+`mm-file-name-trim-whitespace',
+`mm-file-name-collapse-whitespace',
+`mm-file-name-replace-whitespace',
+`capitalize', `downcase', `upcase', and
+`upcase-initials'.")
+
+(defvar mm-path-name-rewrite-functions nil
+  "*List of functions used for rewriting path names of MIME parts.
+This is used when viewing parts externally , and is meant for
+transforming the path name so that non-compliant programs can
+find the file where it's saved.
+
+Each function takes a file name as input and returns a file name.")
+
+(defvar mm-file-name-replace-whitespace nil
+  "String used for replacing whitespace characters; default is `\"_\"'.")
+
 (defcustom mm-default-directory nil
   "The default directory where mm will save files.
 If not set, `default-directory' will be used."
-  :type 'directory
+  :type '(choice directory (const :tag "Default" nil))
+  :group 'mime-display)
+
+(defcustom mm-external-terminal-program "xterm"
+  "The program to start an external terminal."
+  :type 'string
   :group 'mime-display)
 
 ;;; Internal variables.
@@ -362,23 +413,19 @@ The original alist is not modified.  See also `destructive-alist-to-plist'."
          (throw 'found t))))))
 
 (defun mm-handle-set-external-undisplayer (handle function)
- "Set the undisplayer for this handle; postpone undisplaying of viewers
 "Set the undisplayer for this handle; postpone undisplaying of viewers
 for types in mm-keep-viewer-alive-types."
   (if (mm-keep-viewer-alive-p handle)
-    (progn
-     (setq new-handle (copy-sequence handle))
-     (mm-handle-set-undisplayer new-handle function)
-     (mm-handle-set-undisplayer handle nil)
-     (push new-handle mm-postponed-undisplay-list)
-    )
-  (mm-handle-set-undisplayer handle function)
-  )
-)
+      (let ((new-handle (copy-sequence handle)))
+       (mm-handle-set-undisplayer new-handle function)
+       (mm-handle-set-undisplayer handle nil)
+       (push new-handle mm-postponed-undisplay-list))
+    (mm-handle-set-undisplayer handle function)))
 
 (defun mm-destroy-postponed-undisplay-list ()
-  (message "Destroying external MIME viewers")
-  (mm-destroy-parts mm-postponed-undisplay-list)
-)
+  (when mm-postponed-undisplay-list
+    (message "Destroying external MIME viewers")
+    (mm-destroy-parts mm-postponed-undisplay-list)))
 
 (defun mm-dissect-buffer (&optional no-strict-mime)
   "Dissect the current buffer and return a list of MIME handles."
@@ -423,30 +470,33 @@ for types in mm-keep-viewer-alive-types."
           (let ((mm-dissect-default-type (if (equal subtype "digest")
                                              "message/rfc822"
                                            "text/plain")))
-             (add-text-properties 0 (length (car ctl))
-                                  (mm-alist-to-plist (cdr ctl)) (car ctl))
+            (add-text-properties 0 (length (car ctl))
+                                 (mm-alist-to-plist (cdr ctl)) (car ctl))
 
             ;; what really needs to be done here is a way to link a
             ;; MIME handle back to it's parent MIME handle (in a multilevel
             ;; MIME article).  That would probably require changing
             ;; the mm-handle API so we simply store the multipart buffert
             ;; name as a text property of the "multipart/whatever" string.
-             (add-text-properties 0 (length (car ctl))
+            (add-text-properties 0 (length (car ctl))
                                  (list 'buffer (mm-copy-to-buffer))
-                                  (car ctl))
-             (add-text-properties 0 (length (car ctl))
+                                 (car ctl))
+            (add-text-properties 0 (length (car ctl))
                                  (list 'from from)
-                                  (car ctl))
+                                 (car ctl))
             (cons (car ctl) (mm-dissect-multipart ctl))))
          (t
-          (mm-dissect-singlepart
-           ctl
-           (and cte (intern (downcase (mail-header-remove-whitespace
-                                       (mail-header-remove-comments
-                                        cte)))))
-           no-strict-mime
-           (and cd (ignore-errors (mail-header-parse-content-disposition cd)))
-           description id))))
+          (mm-possibly-verify-or-decrypt
+           (mm-dissect-singlepart
+            ctl
+            (and cte (intern (downcase (mail-header-remove-whitespace
+                                        (mail-header-remove-comments
+                                         cte)))))
+            no-strict-mime
+            (and cd (ignore-errors
+                      (mail-header-parse-content-disposition cd)))
+            description id)
+           ctl))))
        (when id
          (when (string-match " *<\\(.*\\)> *" id)
            (setq id (match-string 1 id)))
@@ -528,7 +578,8 @@ external if displayed external."
        (mm-remove-part handle)
       (let* ((type (mm-handle-media-type handle))
             (method (mailcap-mime-info type)))
-       (if (mm-inlined-p handle)
+       (if (and (mm-inlinable-p handle)
+                (mm-inlined-p handle))
            (progn
              (forward-line 1)
              (mm-display-inline handle)
@@ -577,9 +628,13 @@ external if displayed external."
                  (mm-handle-set-undisplayer handle mm)))))
        ;; The function is a string to be executed.
        (mm-insert-part handle)
-       (let* ((dir (make-temp-name (expand-file-name "emm." mm-tmp-directory)))
-              (filename (mail-content-type-get
-                         (mm-handle-disposition handle) 'filename))
+       (let* ((dir (make-temp-name
+                    (expand-file-name "emm." mm-tmp-directory)))
+              (filename (or 
+                         (mail-content-type-get
+                          (mm-handle-disposition handle) 'filename)
+                         (mail-content-type-get
+                          (mm-handle-type handle) 'name)))
               (mime-info (mailcap-mime-info
                           (mm-handle-media-type handle) t))
               (needsterm (or (assoc "needsterm" mime-info)
@@ -596,53 +651,76 @@ external if displayed external."
          (let ((coding-system-for-write mm-binary-coding-system))
            (write-region (point-min) (point-max) file nil 'nomesg))
          (message "Viewing with %s" method)
-         (cond (needsterm
-                (unwind-protect
-                    (start-process "*display*" nil
-                                   "xterm"
-                                   "-e" shell-file-name
-                                   shell-command-switch
-                                   (mm-mailcap-command
-                                    method file (mm-handle-type handle)))
-                  (mm-handle-set-external-undisplayer handle (cons file buffer)))
-                (message "Displaying %s..." (format method file))
-                'external)
-               (copiousoutput
-                (with-current-buffer outbuf
-                  (forward-line 1)
-                  (mm-insert-inline
-                   handle
-                   (unwind-protect
-                       (progn
-                         (call-process shell-file-name nil
-                                       (setq buffer
-                                             (generate-new-buffer " *mm*"))
-                                       nil
-                                       shell-command-switch
-                                       (mm-mailcap-command
-                                        method file (mm-handle-type handle)))
-                         (if (buffer-live-p buffer)
-                             (save-excursion
-                               (set-buffer buffer)
-                               (buffer-string))))
-                     (progn
-                       (ignore-errors (delete-file file))
-                       (ignore-errors (delete-directory
-                                       (file-name-directory file)))
-                       (ignore-errors (kill-buffer buffer))))))
-                'inline)
-               (t
-                (unwind-protect
-                    (start-process "*display*"
-                                   (setq buffer
-                                         (generate-new-buffer " *mm*"))
+         (cond
+          (needsterm
+           (unwind-protect
+               (if window-system
+                   (start-process "*display*" nil
+                                  mm-external-terminal-program
+                                  "-e" shell-file-name
+                                  shell-command-switch
+                                  (mm-mailcap-command
+                                   method file (mm-handle-type handle)))
+                 (require 'term)
+                 (require 'gnus-win)
+                 (set-buffer
+                  (setq buffer
+                        (make-term "display"
                                    shell-file-name
+                                   nil
                                    shell-command-switch
                                    (mm-mailcap-command
-                                    method file (mm-handle-type handle)))
-                  (mm-handle-set-external-undisplayer handle (cons file buffer)))
-                (message "Displaying %s..." (format method file))
-                'external)))))))
+                                    method file
+                                    (mm-handle-type handle)))))
+                 (term-mode)
+                 (term-char-mode)
+                 (set-process-sentinel
+                  (get-buffer-process buffer)
+                  `(lambda (process state)
+                     (if (eq 'exit (process-status process))
+                         (gnus-configure-windows
+                          ',gnus-current-window-configuration))))
+                 (gnus-configure-windows 'display-term))
+             (mm-handle-set-external-undisplayer handle (cons file buffer)))
+           (message "Displaying %s..." (format method file))
+           'external)
+          (copiousoutput
+           (with-current-buffer outbuf
+             (forward-line 1)
+             (mm-insert-inline
+              handle
+              (unwind-protect
+                  (progn
+                    (call-process shell-file-name nil
+                                  (setq buffer
+                                        (generate-new-buffer " *mm*"))
+                                  nil
+                                  shell-command-switch
+                                  (mm-mailcap-command
+                                   method file (mm-handle-type handle)))
+                    (if (buffer-live-p buffer)
+                        (save-excursion
+                          (set-buffer buffer)
+                          (buffer-string))))
+                (progn
+                  (ignore-errors (delete-file file))
+                  (ignore-errors (delete-directory
+                                  (file-name-directory file)))
+                  (ignore-errors (kill-buffer buffer))))))
+           'inline)
+          (t
+           (unwind-protect
+               (start-process "*display*"
+                              (setq buffer
+                                    (generate-new-buffer " *mm*"))
+                              shell-file-name
+                              shell-command-switch
+                              (mm-mailcap-command
+                               method file (mm-handle-type handle)))
+             (mm-handle-set-external-undisplayer
+              handle (cons file buffer)))
+           (message "Displaying %s..." (format method file))
+           'external)))))))
 
 (defun mm-mailcap-command (method file type-list)
   (let ((ctl (cdr type-list))
@@ -659,16 +737,18 @@ external if displayed external."
        (push "%" out))
        ((string= total "%s")
        (setq uses-stdin nil)
-       (push (mm-quote-arg file) out))
+       (push (mm-quote-arg
+              (gnus-map-function mm-path-name-rewrite-functions file)) out))
        ((string= total "%t")
        (push (mm-quote-arg (car type-list)) out))
        (t
        (push (mm-quote-arg (or (cdr (assq (intern sub) ctl)) "")) out))))
     (push (substring method beg (length method)) out)
-    (if uses-stdin
-       (progn
-         (push "<" out)
-         (push (mm-quote-arg file) out)))
+    (when uses-stdin
+      (push "<" out)
+      (push (mm-quote-arg
+            (gnus-map-function mm-path-name-rewrite-functions file))
+           out))
     (mapconcat 'identity (nreverse out) "")))
 
 (defun mm-remove-parts (handles)
@@ -722,7 +802,7 @@ external if displayed external."
         ((consp object)
          (ignore-errors (delete-file (car object)))
          (ignore-errors (delete-directory (file-name-directory (car object))))
-         (ignore-errors (kill-buffer (cdr object))))
+         (ignore-errors (and (cdr object) (kill-buffer (cdr object)))))
         ((bufferp object)
          (when (buffer-live-p object)
            (kill-buffer object)))))
@@ -739,6 +819,18 @@ external if displayed external."
     (when (string-match (car elem) type)
       (return elem))))
 
+(defun mm-automatic-display-p (handle)
+  "Say whether the user wants HANDLE to be displayed automatically."
+  (let ((methods mm-automatic-display)
+       (type (mm-handle-media-type handle))
+       method result)
+    (while (setq method (pop methods))
+      (when (and (not (mm-inline-override-p handle))
+                (string-match method type))
+       (setq result t
+             methods nil)))
+    result))
+
 (defun mm-inlinable-p (handle)
   "Say whether HANDLE can be displayed inline."
   (let ((alist mm-inline-media-tests)
@@ -752,28 +844,14 @@ external if displayed external."
       (pop alist))
     test))
 
-(defun mm-automatic-display-p (handle)
-  "Say whether the user wants HANDLE to be displayed automatically."
-  (let ((methods mm-automatic-display)
-       (type (mm-handle-media-type handle))
-       method result)
-    (while (setq method (pop methods))
-      (when (and (not (mm-inline-override-p handle))
-                (string-match method type)
-                (mm-inlinable-p handle))
-       (setq result t
-             methods nil)))
-    result))
-
 (defun mm-inlined-p (handle)
-  "Say whether the user wants HANDLE to be displayed automatically."
+  "Say whether the user wants HANDLE to be displayed inline."
   (let ((methods mm-inlined-types)
        (type (mm-handle-media-type handle))
        method result)
     (while (setq method (pop methods))
       (when (and (not (mm-inline-override-p handle))
-                (string-match method type)
-                (mm-inlinable-p handle))
+                (string-match method type))
        (setq result t
              methods nil)))
     result))
@@ -841,21 +919,52 @@ external if displayed external."
     (save-excursion
       (if (member (mm-handle-media-supertype handle) '("text" "message"))
          (with-temp-buffer
-           (insert-buffer-substring (mm-handle-buffer handle))
-           (mm-decode-content-transfer-encoding
-            (mm-handle-encoding handle)
-            (mm-handle-media-type handle))
-           (let ((temp (current-buffer)))
-             (set-buffer cur)
-             (insert-buffer-substring temp)))
+           (insert-buffer-substring (mm-handle-buffer handle))
+           (prog1
+               (mm-decode-content-transfer-encoding
+                (mm-handle-encoding handle)
+                (mm-handle-media-type handle))
+             (let ((temp (current-buffer)))
+               (set-buffer cur)
+               (insert-buffer-substring temp))))
        (mm-with-unibyte-buffer
          (insert-buffer-substring (mm-handle-buffer handle))
-         (mm-decode-content-transfer-encoding
-          (mm-handle-encoding handle)
-          (mm-handle-media-type handle))
-         (let ((temp (current-buffer)))
-           (set-buffer cur)
-           (insert-buffer-substring temp)))))))
+         (prog1
+             (mm-decode-content-transfer-encoding
+              (mm-handle-encoding handle)
+              (mm-handle-media-type handle))
+           (let ((temp (current-buffer)))
+             (set-buffer cur)
+             (insert-buffer-substring temp))))))))
+
+(defun mm-file-name-delete-whitespace (file-name)
+  "Remove all whitespace characters from FILE-NAME."
+  (while (string-match "\\s-+" file-name)
+    (setq file-name (replace-match "" t t file-name)))
+  file-name)
+
+(defun mm-file-name-trim-whitespace (file-name)
+  "Remove leading and trailing whitespace characters from FILE-NAME."
+  (when (string-match "\\`\\s-+" file-name)
+    (setq file-name (substring file-name (match-end 0))))
+  (when (string-match "\\s-+\\'" file-name)
+    (setq file-name (substring file-name 0 (match-beginning 0))))
+  file-name)
+
+(defun mm-file-name-collapse-whitespace (file-name)
+  "Collapse multiple whitespace characters in FILE-NAME."
+  (while (string-match "\\s-\\s-+" file-name)
+    (setq file-name (replace-match " " t t file-name)))
+  file-name)
+
+(defun mm-file-name-replace-whitespace (file-name)
+  "Replace whitespace characters in FILE-NAME with underscores.
+Set `mm-file-name-replace-whitespace' to any other string if you do not
+like underscores."
+  (let ((s (or mm-file-name-replace-whitespace "_")))
+    (while (string-match "\\s-" file-name)
+      (setq file-name (replace-match s t t file-name))))
+  file-name)
 
 (defun mm-save-part (handle)
   "Write HANDLE to a file."
@@ -864,7 +973,8 @@ external if displayed external."
                    (mm-handle-disposition handle) 'filename))
         file)
     (when filename
-      (setq filename (file-name-nondirectory filename)))
+      (setq filename (gnus-map-function mm-file-name-rewrite-functions
+                                       (file-name-nondirectory filename))))
     (setq file
          (read-file-name "Save MIME part to: "
                          (expand-file-name
@@ -951,6 +1061,35 @@ external if displayed external."
   "Return the handle(s) referred to by ID."
   (cdr (assoc id mm-content-id-alist)))
 
+(defconst mm-image-type-regexps
+  '(("/\\*.*XPM.\\*/" . xpm)
+    ("P[1-6]" . pbm)
+    ("GIF8" . gif)
+    ("\377\330" . jpeg)
+    ("\211PNG\r\n" . png)
+    ("#define" . xbm)
+    ("\\(MM\0\\*\\)\\|\\(II\\*\0\\)" . tiff)
+    ("%!PS" . postscript))
+  "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
+When the first bytes of an image file match REGEXP, it is assumed to
+be of image type IMAGE-TYPE.")
+
+;; Steal from image.el. image-type-from-data suffers multi-line matching bug.
+(defun mm-image-type-from-buffer ()
+  "Determine the image type from data in the current buffer.
+Value is a symbol specifying the image type or nil if type cannot
+be determined."
+  (let ((types mm-image-type-regexps)
+       type)
+    (goto-char (point-min))
+    (while (and types (null type))
+      (let ((regexp (car (car types)))
+           (image-type (cdr (car types))))
+       (when (looking-at regexp)
+         (setq type image-type))
+       (setq types (cdr types))))
+    type))
+
 (defun mm-get-image (handle)
   "Return an image instance based on HANDLE."
   (let ((type (mm-handle-media-subtype handle))
@@ -971,31 +1110,40 @@ external if displayed external."
          (prog1
              (setq spec
                    (ignore-errors
-                    ;; Avoid testing `make-glyph' since W3 may define
-                    ;; a bogus version of it.
+                     ;; Avoid testing `make-glyph' since W3 may define
+                     ;; a bogus version of it.
                      (if (fboundp 'create-image)
-                         (create-image (buffer-string) (intern type) 'data-p)
-                       (cond
-                        ((equal type "xbm")
-                         ;; xbm images require special handling, since
-                         ;; the only way to create glyphs from these
-                         ;; (without a ton of work) is to write them
-                         ;; out to a file, and then create a file
-                         ;; specifier.
-                         (let ((file (make-temp-name
-                                      (expand-file-name "emm.xbm"
-                                                        mm-tmp-directory))))
-                           (unwind-protect
-                               (progn
-                                 (write-region (point-min) (point-max) file)
-                                 (make-glyph (list (cons 'x file))))
-                             (ignore-errors
-                              (delete-file file)))))
-                        (t
-                         (make-glyph
-                          (vector (intern type) :data (buffer-string))))))))
+                         (create-image (buffer-string) 
+                                       (or (mm-image-type-from-buffer)
+                                           (intern type))
+                                       'data-p)
+                       (mm-create-image-xemacs type))))
            (mm-handle-set-cache handle spec))))))
 
+(defun mm-create-image-xemacs (type)
+  (cond
+   ((equal type "xbm")
+    ;; xbm images require special handling, since
+    ;; the only way to create glyphs from these
+    ;; (without a ton of work) is to write them
+    ;; out to a file, and then create a file
+    ;; specifier.
+    (let ((file (make-temp-name
+                (expand-file-name "emm.xbm"
+                                  mm-tmp-directory))))
+      (unwind-protect
+         (progn
+           (write-region (point-min) (point-max) file)
+           (make-glyph (list (cons 'x file))))
+       (ignore-errors
+         (delete-file file)))))
+   (t
+    (make-glyph
+     (vector 
+      (or (mm-image-type-from-buffer)
+         (intern type))
+      :data (buffer-string))))))
+  
 (defun mm-image-fit-p (handle)
   "Say whether the image in HANDLE will fit the current window."
   (let ((image (mm-get-image handle)))
@@ -1100,10 +1248,22 @@ If RECURSIVE, search recursively."
                         (car handle))))
 
 (defun mm-possibly-verify-or-decrypt (parts ctl)
-  (let ((subtype (cadr (split-string (car ctl) "/")))
+  (let ((type (car ctl))
+       (subtype (cadr (split-string (car ctl) "/")))
        (mm-security-handle ctl) ;; (car CTL) is the type.
        protocol func functest)
     (cond
+     ((or (equal type "application/x-pkcs7-mime")
+         (equal type "application/pkcs7-mime"))
+      (with-temp-buffer
+       (when (and (cond
+                   ((eq mm-decrypt-option 'never) nil)
+                   ((eq mm-decrypt-option 'always) t)
+                   ((eq mm-decrypt-option 'known) t)
+                   (t (y-or-n-p
+                       (format "Decrypt (S/MIME) part? "))))
+                  (mm-view-pkcs7 parts))
+         (setq parts (mm-dissect-buffer t)))))
      ((equal subtype "signed")
       (unless (and (setq protocol
                         (mm-handle-multipart-ctl-parameter ctl 'protocol))
@@ -1172,18 +1332,27 @@ If RECURSIVE, search recursively."
     parts))
 
 (defun mm-multiple-handles (handles)
-   (and (listp (car handles)) 
-       (> (length handles) 1)))
+  (and (listp (car handles))
+       (> (length handles) 1)))
 
-(defun mm-merge-handles (handles1 handles2) 
+(defun mm-merge-handles (handles1 handles2)
   (append
-   (if (listp (car handles1)) 
+   (if (listp (car handles1))
        handles1
      (list handles1))
    (if (listp (car handles2))
        handles2
      (list handles2))))
 
+(defun mm-readable-p (handle)
+  "Say whether the content of HANDLE is readable."
+  (and (< (with-current-buffer (mm-handle-buffer handle)
+           (buffer-size)) 10000)
+       (mm-with-unibyte-buffer
+        (mm-insert-part handle)
+        (and (eq (mm-body-7-or-8) '7bit)
+             (not (mm-long-lines-p 76))))))
+
 (provide 'mm-decode)
 
 ;;; mm-decode.el ends here