X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=lisp%2Fmm-decode.el;h=856a538bbe2b3de0f8ca820789824be6dfbe7623;hb=09868cf7efbfa51562d76580eafc9a7b6b0c8d72;hp=e1d50ed07f9dcc2a6cd490d9f4b951e0dc894f08;hpb=8c620ff2178b0f9079eb742a56f82a17c65c30bb;p=elisp%2Fgnus.git-

diff --git a/lisp/mm-decode.el b/lisp/mm-decode.el
index e1d50ed..856a538 100644
--- a/lisp/mm-decode.el
+++ b/lisp/mm-decode.el
@@ -1,8 +1,9 @@
-;;; mm-decode.el --- Function for decoding MIME things
-;; Copyright (C) 1998 Free Software Foundation, Inc.
+;;; mm-decode.el --- Functions for decoding MIME things
+;; Copyright (C) 1998,99 Free Software Foundation, Inc.
 
 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
-;; This file is not yet part of GNU Emacs.
+;;	MORIOKA Tomohiko <morioka@jaist.ac.jp>
+;; This file is part of GNU Emacs.
 
 ;; GNU Emacs is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -23,112 +24,612 @@
 
 ;;; Code:
 
-(require 'base64)
-(require 'qp)
-(require 'nnheader)
+(require 'mail-parse)
+(require 'mailcap)
+(require 'mm-bodies)
 
-(defvar mm-charset-regexp (concat "[^" "][\000-\040()<>@,\;:\\\"/?.=" "]+"))
+;;; Convenience macros.
 
-(defvar mm-encoded-word-regexp
-  (concat "=\\?\\(" mm-charset-regexp "\\)\\?\\(B\\|Q\\)\\?"
-	  "\\([!->@-~]+\\)\\?="))
+(defmacro mm-handle-buffer (handle)
+  `(nth 0 ,handle))
+(defmacro mm-handle-type (handle)
+  `(nth 1 ,handle))
+(defmacro mm-handle-encoding (handle)
+  `(nth 2 ,handle))
+(defmacro mm-handle-undisplayer (handle)
+  `(nth 3 ,handle))
+(defmacro mm-handle-set-undisplayer (handle function)
+  `(setcar (nthcdr 3 ,handle) ,function))
+(defmacro mm-handle-disposition (handle)
+  `(nth 4 ,handle))
+(defmacro mm-handle-description (handle)
+  `(nth 5 ,handle))
+(defmacro mm-handle-cache (handle)
+  `(nth 6 ,handle))
+(defmacro mm-handle-set-cache (handle contents)
+  `(setcar (nthcdr 6 ,handle) ,contents))
+(defmacro mm-handle-id (handle)
+  `(nth 7 ,handle))
+(defmacro mm-make-handle (&optional buffer type encoding undisplayer
+				    disposition description cache
+				    id)
+  `(list ,buffer ,type ,encoding ,undisplayer
+	 ,disposition ,description ,cache ,id))
 
-(defun mm-decode-words-region (start end)
-  "Decode MIME-encoded words in region between START and END."
-  (interactive "r")
+(defvar mm-inline-media-tests
+  '(("image/jpeg" mm-inline-image (mm-valid-and-fit-image-p 'jpeg handle))
+    ("image/png" mm-inline-image (mm-valid-and-fit-image-p 'png handle))
+    ("image/gif" mm-inline-image (mm-valid-and-fit-image-p 'gif handle))
+    ("image/tiff" mm-inline-image (mm-valid-and-fit-image-p 'tiff handle)) 
+    ("image/xbm" mm-inline-image (mm-valid-and-fit-image-p 'xbm handle))
+    ("image/x-xbitmap" mm-inline-image (mm-valid-and-fit-image-p 'xbm handle))
+    ("image/xpm" mm-inline-image (mm-valid-and-fit-image-p 'xpm handle))
+    ("image/x-pixmap" mm-inline-image (mm-valid-and-fit-image-p 'xpm handle))
+    ("image/bmp" mm-inline-image (mm-valid-and-fit-image-p 'bmp handle))
+    ("text/plain" mm-inline-text t)
+    ("text/enriched" mm-inline-text t)
+    ("text/richtext" mm-inline-text t)
+    ("text/html" mm-inline-text (locate-library "w3"))
+    ("text/x-vcard" mm-inline-text (locate-library "vcard"))
+    ("message/delivery-status" mm-inline-text t)
+    ("message/rfc822" mm-inline-message t)
+    ("text/.*" mm-inline-text t)
+    ("audio/wav" mm-inline-audio
+     (and (or (featurep 'nas-sound) (featurep 'native-sound))
+	  (device-sound-enabled-p)))
+    ("audio/au" mm-inline-audio
+     (and (or (featurep 'nas-sound) (featurep 'native-sound))
+	  (device-sound-enabled-p)))
+    ("multipart/alternative" ignore t)
+    ("multipart/mixed" ignore t)
+    ("multipart/related" ignore t))
+  "Alist of media types/test that say whether the media types can be displayed inline.")
+
+(defvar mm-inlined-types
+  '("image/.*" "text/.*" "message/delivery-status" "message/rfc822")
+  "List of media types that are to be displayed inline.")
+  
+(defvar mm-automatic-display
+  '("text/plain" "text/enriched" "text/richtext" "text/html"
+    "text/x-vcard" "image/.*" "message/delivery-status" "multipart/.*"
+    "message/rfc822")
+  "A list of MIME types to be displayed automatically.")
+
+(defvar mm-attachment-override-types
+  '("text/plain" "text/x-vcard")
+  "Types that should have \"attachment\" ignored if they can be displayed inline.")
+
+(defvar mm-automatic-external-display nil
+  "List of MIME type regexps that will be displayed externally automatically.")
+
+(defvar mm-discouraged-alternatives nil
+  "List of MIME types that are discouraged when viewing multipart/alternative.
+Viewing agents are supposed to view the last possible part of a message,
+as that is supposed to be the richest.  However, users may prefer other
+types instead, and this list says what types are most unwanted.  If,
+for instance, text/html parts are very unwanted, and text/richtech are
+somewhat unwanted, then the value of this variable should be set
+to:
+
+ (\"text/html\" \"text/richtext\")")
+
+(defvar mm-tmp-directory
+  (cond ((fboundp 'temp-directory) (temp-directory))
+	((boundp 'temporary-file-directory) temporary-file-directory)
+	("/tmp/"))
+  "Where mm will store its temporary files.")
+
+(defvar mm-all-images-fit nil
+  "If non-nil, then all images fit in the buffer.")
+
+;;; Internal variables.
+
+(defvar mm-dissection-list nil)
+(defvar mm-last-shell-command "")
+(defvar mm-content-id-alist nil)
+
+;;; The functions.
+
+(defun mm-dissect-buffer (&optional no-strict-mime)
+  "Dissect the current buffer and return a list of MIME handles."
   (save-excursion
-    (save-restriction
-      (narrow-to-region start end)
-      (goto-char (point-min))
-      ;; Remove whitespace between encoded words.
-      (while (re-search-forward
-	      (concat "\\(" mm-encoded-word-regexp "\\)"
-		      "\\(\n?[ \t]\\)+"
-		      "\\(" mm-encoded-word-regexp "\\)")
-	      nil t)
-	(delete-region (goto-char (match-end 1)) (match-beginning 6)))
-      ;; Decode the encoded words.
+    (let (ct ctl type subtype cte cd description id result)
+      (save-restriction
+	(mail-narrow-to-head)
+	(when (or no-strict-mime
+		  (mail-fetch-field "mime-version"))
+	  (setq ct (mail-fetch-field "content-type")
+		ctl (ignore-errors (mail-header-parse-content-type ct))
+		cte (mail-fetch-field "content-transfer-encoding")
+		cd (mail-fetch-field "content-disposition")
+		description (mail-fetch-field "content-description")
+		id (mail-fetch-field "content-id"))))
+      (if (or (not ctl)
+	      (not (string-match "/" (car ctl))))
+	  (mm-dissect-singlepart
+	   '("text/plain") nil no-strict-mime
+	   (and cd (ignore-errors (mail-header-parse-content-disposition cd)))
+	   description)
+	(setq type (split-string (car ctl) "/"))
+	(setq subtype (cadr type)
+	      type (pop type))
+	(setq
+	 result
+	 (cond
+	  ((equal type "multipart")
+	   (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))))
+	(when id
+	  (when (string-match " *<\\(.*\\)> *" id)
+	    (setq id (match-string 1 id)))
+	  (push (cons id result) mm-content-id-alist))
+	result))))
+
+(defun mm-dissect-singlepart (ctl cte &optional force cdl description id)
+  (when (or force
+	    (not (equal "text/plain" (car ctl))))
+    (let ((res (mm-make-handle
+		(mm-copy-to-buffer) ctl cte nil cdl description nil id)))
+      (push (car res) mm-dissection-list)
+      res)))
+
+(defun mm-remove-all-parts ()
+  "Remove all MIME handles."
+  (interactive)
+  (mapcar 'mm-remove-part mm-dissection-list)
+  (setq mm-dissection-list nil))
+
+(defun mm-dissect-multipart (ctl)
+  (goto-char (point-min))
+  (let* ((boundary (concat "\n--" (mail-content-type-get ctl 'boundary)))
+	(close-delimiter (concat (regexp-quote boundary) "--[ \t]*$"))
+	start parts
+	(end (save-excursion
+	       (goto-char (point-max))
+	       (if (re-search-backward close-delimiter nil t)
+		   (match-beginning 0)
+		 (point-max)))))
+    (while (search-forward boundary end t)
+      (goto-char (match-beginning 0))
+      (when start
+	(save-excursion
+	  (save-restriction
+	    (narrow-to-region start (point))
+	    (setq parts (nconc (list (mm-dissect-buffer t)) parts)))))
+      (forward-line 2)
+      (setq start (point)))
+    (when start
+      (save-excursion
+	(save-restriction
+	  (narrow-to-region start end)
+	  (setq parts (nconc (list (mm-dissect-buffer t)) parts)))))
+    (nreverse parts)))
+
+(defun mm-copy-to-buffer ()
+  "Copy the contents of the current buffer to a fresh buffer."
+  (save-excursion
+    (let ((obuf (current-buffer))
+	  beg)
       (goto-char (point-min))
-      (while (re-search-forward mm-encoded-word-regexp nil t)
-	(insert (mm-decode-word
-		 (prog1
-		     (match-string 0)
-		   (delete-region (match-beginning 0) (match-end 0)))))))))
-
-(defun mm-decode-words-string (string)
- "Decode the quoted-printable-encoded STRING and return the results."
- (with-temp-buffer
-   (insert string)
-   (inline
-     (mm-decode-words-region (point-min) (point-max)))
-   (buffer-string)))
-
-(defun mm-decode-word (word)
-  "Decode WORD and return it if it is an encoded word.
-Return WORD if not."
-  (if (not (string-match mm-encoded-word-regexp word))
-      word
-    (or
-     (condition-case nil
-	 (mm-decode-text
-	  (match-string 1 word)
-	  (upcase (match-string 2 word))
-	  (match-string 3 word))
-       (error word))
-     word)))
-
-(eval-and-compile
-  (if (fboundp 'decode-coding-string)
-      (fset 'mm-decode-coding-string 'decode-coding-string)
-    (fset 'mm-decode-coding-string (lambda (s a) s))))
-
-(defun mm-decode-text (charset encoding string)
-  "Decode STRING as an encoded text.
-Valid ENCODINGs are \"B\" and \"Q\".
-If your Emacs implementation can't decode CHARSET, it returns nil."
-  (let ((cs (mm-charset-to-coding-system charset)))
-    (when cs
-      (mm-decode-coding-string
-       (cond
-	((equal "B" encoding)
-	 (base64-decode string))
-	((equal "Q" encoding)
-	 (quoted-printable-decode-string
-	  (nnheader-replace-chars-in-string string ?_ ? )))
-	(t (error "Invalid encoding: %s" encoding)))
-       cs))))
-
-(defvar mm-charset-coding-system-alist
-  (let ((rest
-	 '((us-ascii . iso-8859-1)
-	   (gb2312 . cn-gb-2312)
-	   (iso-2022-jp-2 . iso-2022-7bit-ss2)
-	   (x-ctext . ctext)))
-	(systems (coding-system-list))
-	dest)
-    (while rest
-      (let ((pair (car rest)))
-	(unless (memq (car pair) systems)
-	  (setq dest (cons pair dest))))
-      (setq rest (cdr rest)))
-    dest)
-  "Charset/coding system alist.")
-
-(defun mm-charset-to-coding-system (charset &optional lbt)
-  "Return coding-system corresponding to CHARSET.
-CHARSET is a symbol naming a MIME charset.
-If optional argument LBT (`unix', `dos' or `mac') is specified, it is
-used as the line break code type of the coding system."
-  (when (stringp charset)
-    (setq charset (intern (downcase charset))))
-  (setq charset
-	(or (cdr (assq charset mm-charset-coding-system-alist))
-	    charset))
-  (when lbt
-    (setq charset (intern (format "%s-%s" charset lbt))))
-  (when (memq charset (coding-system-list))
-    charset))
+      (search-forward-regexp "^\n" nil t)
+      (setq beg (point))
+      (set-buffer (generate-new-buffer " *mm*"))
+      (insert-buffer-substring obuf beg)
+      (current-buffer))))
+
+(defun mm-display-part (handle &optional no-default)
+  "Display the MIME part represented by HANDLE.
+Returns nil if the part is removed; inline if displayed inline;
+external if displayed external."
+  (save-excursion
+    (mailcap-parse-mailcaps)
+    (if (mm-handle-displayed-p handle)
+	(mm-remove-part handle)
+      (let* ((type (car (mm-handle-type handle)))
+	     (method (mailcap-mime-info type)))
+	(if (mm-inlined-p type)
+	    (progn
+	      (forward-line 1)
+	      (mm-display-inline handle)
+	      'inline)
+	  (when (or method
+		    (not no-default))
+	    (if (and (not method)
+		     (equal "text" (car (split-string type))))
+		(progn
+		  (forward-line 1)
+		  (mm-insert-inline handle (mm-get-part handle))
+		  'inline)
+	      (mm-display-external
+	       handle (or method 'mailcap-save-binary-file))
+	      'external)))))))
+
+(defun mm-display-external (handle method)
+  "Display HANDLE using METHOD."
+  (mm-with-unibyte-buffer
+    (if (functionp method)
+	(let ((cur (current-buffer)))
+	  (if (eq method 'mailcap-save-binary-file)
+	      (progn
+		(set-buffer (generate-new-buffer "*mm*"))
+		(setq method nil))
+	    (mm-insert-part handle)
+	    (let ((win (get-buffer-window cur t)))
+	      (when win
+		(select-window win)))
+	    (switch-to-buffer (generate-new-buffer "*mm*")))
+	  (buffer-disable-undo)
+	  (mm-set-buffer-file-coding-system mm-binary-coding-system)
+	  (insert-buffer-substring cur)
+	  (message "Viewing with %s" method)
+	  (let ((mm (current-buffer))
+		(non-viewer (assoc "non-viewer"
+				   (mailcap-mime-info
+				    (car (mm-handle-type handle)) t))))
+	    (unwind-protect
+		(if method
+		    (funcall method)
+		  (mm-save-part handle))
+	      (when (and (not non-viewer)
+			 method)
+		(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))
+	     (needsterm (assoc "needsterm"
+			       (mailcap-mime-info
+				(car (mm-handle-type handle)) t)))
+	     process file buffer)
+	;; We create a private sub-directory where we store our files.
+	(make-directory dir)
+	(set-file-modes dir 448)
+	(if filename
+	    (setq file (expand-file-name (file-name-nondirectory filename)
+					 dir))
+	  (setq file (make-temp-name (expand-file-name "mm." dir))))
+	(write-region (point-min) (point-max) file nil 'nomesg)
+	(message "Viewing with %s" method)
+	(unwind-protect
+	    (setq process
+		  (if needsterm
+		      (start-process "*display*" nil
+				     "xterm"
+				     "-e" shell-file-name "-c"
+				     (format method
+					     (mm-quote-arg file)))
+		    (start-process "*display*"
+				   (setq buffer (generate-new-buffer "*mm*"))
+				   shell-file-name
+				   "-c" (format method
+						(mm-quote-arg file)))))
+	  (mm-handle-set-undisplayer handle (cons file buffer)))
+	(message "Displaying %s..." (format method file))))))
+
+(defun mm-remove-parts (handles)
+  "Remove the displayed MIME parts represented by HANDLE."
+  (if (and (listp handles)
+	   (bufferp (car handles)))
+      (mm-remove-part handles)
+    (let (handle)
+      (while (setq handle (pop handles))
+	(cond
+	 ((stringp handle)
+	  )
+	 ((and (listp handle)
+	       (stringp (car handle)))
+	  (mm-remove-parts (cdr handle)))
+	 (t
+	  (mm-remove-part handle)))))))
+
+(defun mm-destroy-parts (handles)
+  "Remove the displayed MIME parts represented by HANDLE."
+  (if (and (listp handles)
+	   (bufferp (car handles)))
+      (mm-destroy-part handles)
+    (let (handle)
+      (while (setq handle (pop handles))
+	(cond
+	 ((stringp handle)
+	  )
+	 ((and (listp handle)
+	       (stringp (car handle)))
+	  (mm-destroy-parts (cdr handle)))
+	 (t
+	  (mm-destroy-part handle)))))))
+
+(defun mm-remove-part (handle)
+  "Remove the displayed MIME part represented by HANDLE."
+  (when (listp handle)
+    (let ((object (mm-handle-undisplayer handle)))
+      (ignore-errors
+	(cond
+	 ;; Internally displayed part.
+	 ((mm-annotationp object)
+	  (delete-annotation object))
+	 ((or (functionp object)
+	      (and (listp object)
+		   (eq (car object) 'lambda)))
+	  (funcall object))
+	 ;; Externally displayed part.
+	 ((consp object)
+	  (ignore-errors (delete-file (car object)))
+	  (ignore-errors (delete-directory (file-name-directory (car object))))
+	  (ignore-errors (kill-buffer (cdr object))))
+	 ((bufferp object)
+	  (when (buffer-live-p object)
+	    (kill-buffer object)))))
+      (mm-handle-set-undisplayer handle nil))))
+
+(defun mm-display-inline (handle)
+  (let* ((type (car (mm-handle-type handle)))
+	 (function (cadr (assoc type mm-inline-media-tests))))
+    (funcall function handle)
+    (goto-char (point-min))))
+
+(defun mm-inlinable-p (type)
+  "Say whether TYPE can be displayed inline."
+  (let ((alist mm-inline-media-tests)
+	test)
+    (while alist
+      (when (equal type (caar alist))
+	(setq test (caddar alist)
+	      alist nil)
+	(setq test (eval test)))
+      (pop alist))
+    test))
+
+(defun mm-automatic-display-p (type)
+  "Say whether the user wants TYPE to be displayed automatically."
+  (let ((methods mm-automatic-display)
+	method result)
+    (while (setq method (pop methods))
+      (when (and (string-match method type)
+		 (mm-inlinable-p type))
+	(setq result t
+	      methods nil)))
+    result))
+
+(defun mm-inlined-p (type)
+  "Say whether the user wants TYPE to be displayed automatically."
+  (let ((methods mm-inlined-types)
+	method result)
+    (while (setq method (pop methods))
+      (when (and (string-match method type)
+		 (mm-inlinable-p type))
+	(setq result t
+	      methods nil)))
+    result))
+
+(defun mm-attachment-override-p (type)
+  "Say whether TYPE should have attachment behavior overridden."
+  (let ((types mm-attachment-override-types)
+	ty)
+    (catch 'found
+      (while (setq ty (pop types))
+	(when (and (string-match ty type)
+		   (mm-inlinable-p type))
+	  (throw 'found t))))))
+
+(defun mm-automatic-external-display-p (type)
+  "Return the user-defined method for TYPE."
+  (let ((methods mm-automatic-external-display)
+	method result)
+    (while (setq method (pop methods))
+      (when (string-match method type)
+	(setq result t
+	      methods nil)))
+    result))
+
+(defun mm-destroy-part (handle)
+  "Destroy the data structures connected to HANDLE."
+  (when (listp handle)
+    (mm-remove-part handle)
+    (when (buffer-live-p (mm-handle-buffer handle))
+      (kill-buffer (mm-handle-buffer handle)))))
+
+(defun mm-handle-displayed-p (handle)
+  "Say whether HANDLE is displayed or not."
+  (mm-handle-undisplayer handle))
+
+;;;
+;;; Functions for outputting parts
+;;;
+
+(defun mm-get-part (handle)
+  "Return the contents of HANDLE as a string."
+  (mm-with-unibyte-buffer
+    (mm-insert-part handle)
+    (buffer-string)))
+
+(defun mm-insert-part (handle)
+  "Insert the contents of HANDLE in the current buffer."
+  (let ((cur (current-buffer)))
+    (save-excursion
+      (if (member (car (split-string (car (mm-handle-type handle)) "/"))
+		  '("text" "message"))
+	  (with-temp-buffer
+	    (insert-buffer-substring (mm-handle-buffer handle))
+	    (mm-decode-content-transfer-encoding
+	     (mm-handle-encoding handle)
+	     (car (mm-handle-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)
+	   (car (mm-handle-type handle)))
+	  (let ((temp (current-buffer)))
+	    (set-buffer cur)
+	    (insert-buffer-substring temp)))))))
+
+(defvar mm-default-directory nil)
+
+(defun mm-save-part (handle)
+  "Write HANDLE to a file."
+  (let* ((name (mail-content-type-get (mm-handle-type handle) 'name))
+	 (filename (mail-content-type-get
+		    (mm-handle-disposition handle) 'filename))
+	 file)
+    (when filename
+      (setq filename (file-name-nondirectory filename)))
+    (setq file
+	  (read-file-name "Save MIME part to: "
+			  (expand-file-name
+			   (or filename name "")
+			   (or mm-default-directory default-directory))))
+    (setq mm-default-directory (file-name-directory file))
+    (when (or (not (file-exists-p file))
+	      (yes-or-no-p (format "File %s already exists; overwrite? "
+				   file)))
+      (mm-save-part-to-file handle file))))
+
+(defun mm-save-part-to-file (handle file)
+  (mm-with-unibyte-buffer
+    (mm-insert-part handle)
+    ;; Now every coding system is 100% binary within mm-with-unibyte-buffer
+    ;; Is text still special?
+    (let ((coding-system-for-write
+	   (if (equal "text" (car (split-string
+				   (car (mm-handle-type handle)) "/")))
+	       buffer-file-coding-system
+	     'binary))
+	  ;; Don't re-compress .gz & al.  Arguably we should make
+	  ;; `file-name-handler-alist' nil, but that would chop
+	  ;; ange-ftp which it's reasonable to use here.
+	  (inhibit-file-name-operation 'write-region)
+	  (inhibit-file-name-handlers
+	   (if (equal (car (mm-handle-type handle))
+		      "application/octet-stream")
+	       (cons 'jka-compr-handler inhibit-file-name-handlers)
+	     inhibit-file-name-handlers)))
+      (write-region (point-min) (point-max) file))))
+
+(defun mm-pipe-part (handle)
+  "Pipe HANDLE to a process."
+  (let* ((name (mail-content-type-get (mm-handle-type handle) 'name))
+	 (command
+	  (read-string "Shell command on MIME part: " mm-last-shell-command)))
+    (mm-with-unibyte-buffer
+      (mm-insert-part handle)
+      (shell-command-on-region (point-min) (point-max) command nil))))
+
+(defun mm-interactively-view-part (handle)
+  "Display HANDLE using METHOD."
+  (let* ((type (car (mm-handle-type handle)))
+	 (methods
+	  (mapcar (lambda (i) (list (cdr (assoc 'viewer i))))
+		  (mailcap-mime-info type 'all)))
+	 (method (completing-read "Viewer: " methods)))
+    (mm-display-external (copy-sequence handle) method)))
+
+(defun mm-preferred-alternative (handles &optional preferred)
+  "Say which of HANDLES are preferred."
+  (let ((prec (if preferred (list preferred)
+		(mm-preferred-alternative-precedence handles)))
+	p h result type handle)
+    (while (setq p (pop prec))
+      (setq h handles)
+      (while h
+	(setq type
+	      (if (stringp (caar h))
+		  (caar h)
+		(car (mm-handle-type (car h)))))
+	(setq handle (car h))
+	(when (and (equal p type)
+		   (mm-automatic-display-p type)
+		   (or (stringp (caar h))
+		       (not (mm-handle-disposition (car h)))
+		       (equal (car (mm-handle-disposition (car h)))
+			      "inline")))
+	  (setq result (car h)
+		h nil
+		prec nil))
+	(pop h)))
+    result))
+
+(defun mm-preferred-alternative-precedence (handles)
+  "Return the precedence based on HANDLES and mm-discouraged-alternatives."
+  (let ((seq (nreverse (mapcar (lambda (h)
+				 (car (mm-handle-type h))) handles))))
+    (dolist (disc (reverse mm-discouraged-alternatives))
+      (dolist (elem (copy-sequence seq))
+	(when (string-match disc elem)
+	  (setq seq (nconc (delete elem seq) (list elem))))))
+    seq))
+
+(defun mm-get-content-id (id)
+  "Return the handle(s) referred to by ID."
+  (cdr (assoc id mm-content-id-alist)))
+
+(defun mm-get-image (handle)
+  "Return an image instance based on HANDLE."
+  (let ((type (cadr (split-string (car (mm-handle-type handle)) "/")))
+	spec)
+    ;; Allow some common translations.
+    (setq type
+	  (cond
+	   ((equal type "x-pixmap")
+	    "xpm")
+	   ((equal type "x-xbitmap")
+	    "xbm")
+	   (t type)))
+    (or (mm-handle-cache handle)
+	(mm-with-unibyte-buffer
+	  (mm-insert-part handle)
+	  (prog1
+	      (setq spec
+		    (ignore-errors
+		      (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)))))))
+	    (mm-handle-set-cache handle spec))))))
+
+(defun mm-image-fit-p (handle)
+  "Say whether the image in HANDLE will fit the current window."
+  (let ((image (mm-get-image handle)))
+    (or mm-all-images-fit
+	(and (< (glyph-width image) (window-pixel-width))
+	     (< (glyph-height image) (window-pixel-height))))))
+
+(defun mm-valid-image-format-p (format)
+  "Say whether FORMAT can be displayed natively by Emacs."
+  (and (fboundp 'valid-image-instantiator-format-p)
+       (valid-image-instantiator-format-p format)))
+
+(defun mm-valid-and-fit-image-p (format handle)
+  "Say whether FORMAT can be displayed natively and HANDLE fits the window."
+  (and window-system
+       (mm-valid-image-format-p format)
+       (mm-image-fit-p handle)))
 
 (provide 'mm-decode)
 
-;; qp.el ends here
+;; mm-decode.el ends here