;;; mm-mailcap.el --- Functions for displaying MIME parts
;; Copyright (C) 1998,99 Free Software Foundation, Inc.

;; Author: William M. Perry <wmperry@aventail.com>
;;	Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: news, mail

;; 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 2, 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; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;;; Code:

(eval-when-compile (require 'cl))
(require 'mail-parse)
(require 'mm-util)

(defvar mm-mailcap-parse-args-syntax-table
  (let ((table (copy-syntax-table emacs-lisp-mode-syntax-table)))
    (modify-syntax-entry ?' "\"" table)
    (modify-syntax-entry ?` "\"" table)
    (modify-syntax-entry ?{ "(" table)
    (modify-syntax-entry ?} ")" table)
    table)
  "A syntax table for parsing sgml attributes.")

(defvar mm-mailcap-mime-data
  '(("application"
     ("x-x509-ca-cert"
      (viewer . ssl-view-site-cert)
      (test . (fboundp 'ssl-view-site-cert))
      (type . "application/x-x509-ca-cert"))
     ("x-x509-user-cert"
      (viewer . ssl-view-user-cert)
      (test . (fboundp 'ssl-view-user-cert))
      (type . "application/x-x509-user-cert"))
     ("octet-stream"
      (viewer . mm-mailcap-save-binary-file)
      (non-viewer . t)
      (type ."application/octet-stream"))
     ("dvi"
      (viewer . "open %s")
      (type   . "application/dvi")
      (test   . (eq (mm-device-type) 'ns)))
     ("dvi"
      (viewer . "xdvi %s")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11")
      (type   . "application/dvi"))
     ("dvi"
      (viewer . "dvitty %s")
      (test   . (not (getenv "DISPLAY")))
      (type   . "application/dvi"))
     ("emacs-lisp"
      (viewer . mm-mailcap-maybe-eval)
      (type   . "application/emacs-lisp"))
     ("x-tar"
      (viewer . mm-mailcap-save-binary-file)
      (non-viewer . t)
      (type   . "application/x-tar"))
     ("x-latex"
      (viewer . tex-mode)
      (test   . (fboundp 'tex-mode))
      (type   . "application/x-latex"))
     ("x-tex"
      (viewer . tex-mode)
      (test   . (fboundp 'tex-mode))
      (type   . "application/x-tex"))
     ("latex"
      (viewer . tex-mode)
      (test   . (fboundp 'tex-mode))
      (type   . "application/latex"))
     ("tex"
      (viewer . tex-mode)
      (test   . (fboundp 'tex-mode))
      (type   . "application/tex"))
     ("texinfo"
      (viewer . texinfo-mode)
      (test   . (fboundp 'texinfo-mode))
      (type   . "application/tex"))
     ("zip"
      (viewer . mm-mailcap-save-binary-file)
      (non-viewer . t)
      (type   . "application/zip")
      ("copiousoutput"))
     ("pdf"
      (viewer . "acroread %s")
      (type   . "application/pdf"))
     ("postscript"
      (viewer . "open %s")
      (type   . "application/postscript")
      (test   . (eq (mm-device-type) 'ns)))
     ("postscript"
      (viewer . "ghostview -dSAFER %s")
      (type . "application/postscript")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11"))
     ("postscript"
      (viewer . "ps2ascii %s")
      (type . "application/postscript")
      (test . (not (getenv "DISPLAY")))
      ("copiousoutput")))
    ("audio"
     ("x-mpeg"
      (viewer . "maplay %s")
      (type   . "audio/x-mpeg"))
     (".*"
      (viewer . "showaudio")
      (type   . "audio/*")))
    ("message"
     ("rfc-*822"
      (viewer . mm-view-message)
      (test   . (and (featurep 'gnus)
		     (gnus-alive-p)))
      (type   . "message/rfc822"))
     ("rfc-*822"
      (viewer . vm-mode)
      (test   . (fboundp 'vm-mode))
      (type   . "message/rfc822"))
     ("rfc-*822"
      (viewer . w3-mode)
      (test   . (fboundp 'w3-mode))
      (type   . "message/rfc822"))
     ("rfc-*822"
      (viewer . view-mode)
      (test   . (fboundp 'view-mode))
      (type   . "message/rfc822"))
     ("rfc-*822"
      (viewer . fundamental-mode)
      (type   . "message/rfc822")))
    ("image"
     ("x-xwd"
      (viewer  . "xwud -in %s")
      (type    . "image/x-xwd")
      ("compose" . "xwd -frame > %s")
      (test    . (eq (mm-device-type) 'x))
      ("needsx11"))
     ("x11-dump"
      (viewer . "xwud -in %s")
      (type . "image/x-xwd")
      ("compose" . "xwd -frame > %s")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11"))
     ("windowdump"
      (viewer . "xwud -in %s")
      (type . "image/x-xwd")
      ("compose" . "xwd -frame > %s")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11"))
     (".*"
      (viewer . "aopen %s")
      (type   . "image/*")
      (test   . (eq (mm-device-type) 'ns)))
     (".*"
      (viewer . "display %s")
      (type . "image/*")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11"))
     (".*"
      (viewer . "ee %s")
      (type . "image/*")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11")))
    ("text"
     ("plain"
      (viewer  . w3-mode)
      (test    . (fboundp 'w3-mode))
      (type    . "text/plain"))
     ("plain"
      (viewer  . view-mode)
      (test    . (fboundp 'view-mode))
      (type    . "text/plain"))
     ("plain"
      (viewer  . fundamental-mode)
      (type    . "text/plain"))
     ("enriched"
      (viewer . enriched-decode-region)
      (test   . (fboundp 'enriched-decode))
      (type   . "text/enriched"))
     ("html"
      (viewer . mm-w3-prepare-buffer)
      (test   . (fboundp 'w3-prepare-buffer))
      (type   . "text/html")))
    ("video"
     ("mpeg"
      (viewer . "mpeg_play %s")
      (type   . "video/mpeg")
      (test   . (eq (mm-device-type) 'x))
      ("needsx11")))
    ("x-world"
     ("x-vrml"
      (viewer  . "webspace -remote %s -URL %u")
      (type    . "x-world/x-vrml")
      ("description"
       "VRML document")))
    ("archive"
     ("tar"
      (viewer . tar-mode)
      (type . "archive/tar")
      (test . (fboundp 'tar-mode)))))
  "The mailcap structure is an assoc list of assoc lists.
1st assoc list is keyed on the major content-type
2nd assoc list is keyed on the minor content-type (which can be a regexp)

Which looks like:
-----------------
 ((\"application\"
   (\"postscript\" . <info>))
  (\"text\"
   (\"plain\" . <info>)))

Where <info> is another assoc list of the various information
related to the mailcap RFC.  This is keyed on the lowercase
attribute name (viewer, test, etc).  This looks like:
 ((viewer . viewerinfo)
  (test   . testinfo)
  (xxxx   . \"string\"))

Where viewerinfo specifies how the content-type is viewed.  Can be
a string, in which case it is run through a shell, with
appropriate parameters, or a symbol, in which case the symbol is
funcall'd, with the buffer as an argument.

testinfo is a list of strings, or nil.  If nil, it means the
viewer specified is always valid.  If it is a list of strings,
these are used to determine whether a viewer passes the 'test' or
not.")

(defvar mm-mailcap-download-directory nil
  "*Where downloaded files should go by default.")

(defvar mm-mailcap-temporary-directory
  (cond ((fboundp 'temp-directory) (temp-directory))
	((boundp 'temporary-file-directory) temporary-file-directory)
	("/tmp/"))
  "*Where temporary files go.")

;;;
;;; Utility functions
;;;

(defun mm-mailcap-generate-unique-filename (&optional fmt)
  "Generate a unique filename in mm-mailcap-temporary-directory."
  (if (not fmt)
      (let ((base (format "mm-mailcap-tmp.%d" (user-real-uid)))
	    (fname "")
	    (x 0))
	(setq fname (format "%s%d" base x))
	(while (file-exists-p
		(expand-file-name fname mm-mailcap-temporary-directory))
	  (setq x (1+ x)
		fname (concat base (int-to-string x))))
	(expand-file-name fname mm-mailcap-temporary-directory))
    (let ((base (concat "mm" (int-to-string (user-real-uid))))
	  (fname "")
	  (x 0))
      (setq fname (format fmt (concat base (int-to-string x))))
      (while (file-exists-p
	      (expand-file-name fname mm-mailcap-temporary-directory))
	(setq x (1+ x)
	      fname (format fmt (concat base (int-to-string x)))))
      (expand-file-name fname mm-mailcap-temporary-directory))))

(defun mm-mailcap-save-binary-file ()
  (goto-char (point-min))
  (unwind-protect
      (let ((file (read-file-name
		   "Filename to save as: "
		   (or mm-mailcap-download-directory "~/")))
	    (require-final-newline nil))
	(write-region (point-min) (point-max) file))
    (kill-buffer (current-buffer))))

(defun mm-mailcap-maybe-eval ()
  "Maybe evaluate a buffer of emacs lisp code."
  (if (yes-or-no-p "This is emacs-lisp code, evaluate it? ")
      (eval-buffer (current-buffer))
    (emacs-lisp-mode)))

;;;
;;; The mailcap parser
;;;

(defun mm-mailcap-replace-regexp (regexp to-string)
  ;; Quiet replace-regexp.
  (goto-char (point-min))
  (while (re-search-forward regexp nil t)
    (replace-match to-string t nil)))

(defvar mm-mailcap-parsed-p nil)

(defun mm-mailcap-parse-mailcaps (&optional path force)
  "Parse out all the mailcaps specified in a unix-style path string PATH.
If FORCE, re-parse even if already parsed."
  (interactive (list nil t))
  (when (or (not mm-mailcap-parsed-p)
	    force)
    (cond
     (path nil)
     ((getenv "MAILCAPS") (setq path (getenv "MAILCAPS")))
     ((memq system-type '(ms-dos ms-windows windows-nt))
      (setq path (mapconcat 'expand-file-name
			    '("~/mail.cap" "~/etc/mail.cap" "~/.mailcap")
			    ";")))
     (t (setq path (mapconcat 'expand-file-name
			      '("~/.mailcap"
				"/etc/mailcap:/usr/etc/mailcap"
				"/usr/local/etc/mailcap") ":"))))
    (let ((fnames (reverse
		   (split-string
		    path (if (memq system-type
				   '(ms-dos ms-windows windows-nt))
			     ";"
			   ":"))))
	  fname)
      (while fnames
	(setq fname (car fnames))
	(if (and (file-exists-p fname) (file-readable-p fname)
		 (file-regular-p fname))
	    (mm-mailcap-parse-mailcap (car fnames)))
	(setq fnames (cdr fnames))))
    (setq mm-mailcap-parsed-p t)))

(defun mm-mailcap-parse-mailcap (fname)
  ;; Parse out the mailcap file specified by FNAME
  (let (major				; The major mime type (image/audio/etc)
	minor				; The minor mime type (gif, basic, etc)
	save-pos			; Misc saved positions used in parsing
	viewer				; How to view this mime type
	info				; Misc info about this mime type
	)
    (with-temp-buffer
      (insert-file-contents fname)
      (set-syntax-table mm-mailcap-parse-args-syntax-table)
      (mm-mailcap-replace-regexp "#.*" "")	; Remove all comments
      (mm-mailcap-replace-regexp "\n+" "\n") ; And blank lines
      (mm-mailcap-replace-regexp "\\\\[ \t\n]+" " ") ; And collapse spaces
      (mm-mailcap-replace-regexp (concat (regexp-quote "\\") "[ \t]*\n") "")
      (goto-char (point-max))
      (skip-chars-backward " \t\n")
      (delete-region (point) (point-max))
      (goto-char (point-min))
      (while (not (eobp))
	(skip-chars-forward " \t\n")
	(setq save-pos (point)
	      info nil)
	(skip-chars-forward "^/; \t\n")
	(downcase-region save-pos (point))
	(setq major (buffer-substring save-pos (point)))
	(skip-chars-forward " \t\n")
	(setq minor "")
	(when (eq (char-after) ?/)
	  (forward-char)
	  (skip-chars-forward " \t\n")
	  (setq save-pos (point))
	  (skip-chars-forward "^; \t\n")
	  (downcase-region save-pos (point))
	  (setq minor
		(cond
		 ((eq ?* (or (char-after save-pos) 0)) ".*")
		 ((= (point) save-pos) ".*")
		 (t (regexp-quote (buffer-substring save-pos (point)))))))
	(skip-chars-forward " \t\n")
	;;; Got the major/minor chunks, now for the viewers/etc
	;;; The first item _must_ be a viewer, according to the
	;;; RFC for mailcap files (#1343)
	(setq viewer "")
	(when (eq (char-after) ?\;) 
	  (forward-char)
	  (skip-chars-forward " \t\n")
	  (setq save-pos (point))
	  (skip-chars-forward "^;\n")
	  ;; skip \;
	  (while (eq (char-before) ?\\)
	    (backward-delete-char 1)
	    (forward-char)
	    (skip-chars-forward "^;\n"))
	  (if (eq (or (char-after save-pos) 0) ?')
	      (setq viewer (progn
			     (narrow-to-region (1+ save-pos) (point))
			     (goto-char (point-min))
			     (prog1
				 (read (current-buffer))
			       (goto-char (point-max))
			       (widen))))
	    (setq viewer (buffer-substring save-pos (point)))))
	(setq save-pos (point))
	(end-of-line)
	(unless (equal viewer "") 
	  (setq info (nconc (list (cons 'viewer viewer)
				  (cons 'type (concat major "/"
						      (if (string= minor ".*")
							  "*" minor))))
			    (mm-mailcap-parse-mailcap-extras save-pos (point))))
	  (mm-mailcap-mailcap-entry-passes-test info)
	  (mm-mailcap-add-mailcap-entry major minor info))))))

(defun mm-mailcap-parse-mailcap-extras (st nd)
  ;; Grab all the extra stuff from a mailcap entry
  (let (
	name				; From name=
	value				; its value
	results				; Assoc list of results
	name-pos			; Start of XXXX= position
	val-pos				; Start of value position
	done				; Found end of \'d ;s?
	)
    (save-restriction
      (narrow-to-region st nd)
      (goto-char (point-min))
      (skip-chars-forward " \n\t;")
      (while (not (eobp))
	(setq done nil)
	(setq name-pos (point))
	(skip-chars-forward "^ \n\t=;")
	(downcase-region name-pos (point))
	(setq name (buffer-substring name-pos (point)))
	(skip-chars-forward " \t\n")
	(if (not (eq (char-after (point)) ?=)) ; There is no value
	    (setq value t)
	  (skip-chars-forward " \t\n=")
	  (setq val-pos (point))
	  (if (memq (char-after val-pos) '(?\" ?'))
	      (progn
		(setq val-pos (1+ val-pos))
		(condition-case nil
		    (progn
		      (forward-sexp 1)
		      (backward-char 1))
		  (error (goto-char (point-max)))))
	    (while (not done)
	      (skip-chars-forward "^;")
	      (if (eq (char-after (1- (point))) ?\\ )
		  (progn
		    (subst-char-in-region (1- (point)) (point) ?\\ ? )
		    (skip-chars-forward ";"))
		(setq done t))))
	  (setq	value (buffer-substring val-pos (point))))
	(setq results (cons (cons name value) results))
	(skip-chars-forward " \";\n\t"))
      results)))

(defun mm-mailcap-mailcap-entry-passes-test (info)
  ;; Return t iff a mailcap entry passes its test clause or no test
  ;; clause is present.
  (let (status				; Call-process-regions return value
	(test (assq 'test info))	; The test clause
	)
    (setq status (and test (split-string (cdr test) " ")))
    (if (and (or (assoc "needsterm" info)
		 (assoc "needsterminal" info)
		 (assoc "needsx11" info))
	     (not (getenv "DISPLAY")))
	(setq status nil)
      (cond
       ((and (equal (nth 0 status) "test")
	     (equal (nth 1 status) "-n")
	     (or (equal (nth 2 status) "$DISPLAY")
		 (equal (nth 2 status) "\"$DISPLAY\"")))
	(setq status (if (getenv "DISPLAY") t nil)))
       ((and (equal (nth 0 status) "test")
	     (equal (nth 1 status) "-z")
	     (or (equal (nth 2 status) "$DISPLAY")
		 (equal (nth 2 status) "\"$DISPLAY\"")))
	(setq status (if (getenv "DISPLAY") nil t)))
       (test nil)
       (t nil)))
    (and test (listp test) (setcdr test status))))

;;;
;;; The action routines.
;;;

(defun mm-mailcap-possible-viewers (major minor)
  ;; Return a list of possible viewers from MAJOR for minor type MINOR
  (let ((exact '())
	(wildcard '()))
    (while major
      (cond
       ((equal (car (car major)) minor)
	(setq exact (cons (cdr (car major)) exact)))
       ((and minor (string-match (car (car major)) minor))
	(setq wildcard (cons (cdr (car major)) wildcard))))
      (setq major (cdr major)))
    (nconc (nreverse exact) (nreverse wildcard))))

(defun mm-mailcap-unescape-mime-test (test type-info)
  (let (save-pos save-chr subst)
    (cond
     ((symbolp test) test)
     ((and (listp test) (symbolp (car test))) test)
     ((or (stringp test)
	  (and (listp test) (stringp (car test))
	       (setq test (mapconcat 'identity test " "))))
      (with-temp-buffer
	(insert test)
	(goto-char (point-min))
	(while (not (eobp))
	  (skip-chars-forward "^%")
	  (if (/= (- (point)
		     (progn (skip-chars-backward "\\\\")
			    (point)))
		  0)			; It is an escaped %
	      (progn
		(delete-char 1)
		(skip-chars-forward "%."))
	    (setq save-pos (point))
	    (skip-chars-forward "%")
	    (setq save-chr (char-after (point)))
	    (cond
	     ((null save-chr) nil)
	     ((= save-chr ?t)
	      (delete-region save-pos (progn (forward-char 1) (point)))
	      (insert (or (cdr (assq 'type type-info)) "\"\"")))
	     ((= save-chr ?M)
	      (delete-region save-pos (progn (forward-char 1) (point)))
	      (insert "\"\""))
	     ((= save-chr ?n)
	      (delete-region save-pos (progn (forward-char 1) (point)))
	      (insert "\"\""))
	     ((= save-chr ?F)
	      (delete-region save-pos (progn (forward-char 1) (point)))
	      (insert "\"\""))
	     ((= save-chr ?{)
	      (forward-char 1)
	      (skip-chars-forward "^}")
	      (downcase-region (+ 2 save-pos) (point))
	      (setq subst (buffer-substring (+ 2 save-pos) (point)))
	      (delete-region save-pos (1+ (point)))
	      (insert (or (cdr (assoc subst type-info)) "\"\"")))
	     (t nil))))
	(buffer-string)))
     (t (error "Bad value to mm-mailcap-unescape-mime-test. %s" test)))))

(defvar mm-mailcap-viewer-test-cache nil)

(defun mm-mailcap-viewer-passes-test (viewer-info type-info)
  ;; Return non-nil iff the viewer specified by VIEWER-INFO passes its
  ;; test clause (if any).
  (let* ((test-info (assq 'test viewer-info))
	 (test (cdr test-info))
	 (otest test)
	 (viewer (cdr (assoc 'viewer viewer-info)))
	 (default-directory (expand-file-name "~/"))
	 status parsed-test cache result)
    (if (setq cache (assoc test mm-mailcap-viewer-test-cache))
	(cadr cache)
      (setq
       result
       (cond
	((not test-info) t)		; No test clause
	((not test) nil)		; Already failed test
	((eq test t) t)			; Already passed test
	((and (symbolp test)		; Lisp function as test
	      (fboundp test))
	 (funcall test type-info))
	((and (symbolp test)		; Lisp variable as test
	      (boundp test))
	 (symbol-value test))
	((and (listp test)		; List to be eval'd
	      (symbolp (car test)))
	 (eval test))
	(t
	 (setq test (mm-mailcap-unescape-mime-test test type-info)
	       test (list shell-file-name nil nil nil
			  shell-command-switch test)
	       status (apply 'call-process test))
	 (= 0 status))))
      (push (list otest result) mm-mailcap-viewer-test-cache)
      result)))

(defun mm-mailcap-add-mailcap-entry (major minor info)
  (let ((old-major (assoc major mm-mailcap-mime-data)))
    (if (null old-major)		; New major area
	(setq mm-mailcap-mime-data
	      (cons (cons major (list (cons minor info)))
		    mm-mailcap-mime-data))
      (let ((cur-minor (assoc minor old-major)))
	(cond
	 ((or (null cur-minor)		; New minor area, or
	      (assq 'test info))	; Has a test, insert at beginning
	  (setcdr old-major (cons (cons minor info) (cdr old-major))))
	 ((and (not (assq 'test info))	; No test info, replace completely
	       (not (assq 'test cur-minor)))
	  (setcdr cur-minor info))
	 (t
	  (setcdr old-major (cons (cons minor info) (cdr old-major)))))))))

(defun mm-mailcap-add (type viewer &optional test)
  "Add VIEWER as a handler for TYPE.
If TEST is not given, it defaults to t."
  (let ((tl (split-string type "/")))
    (when (or (not (car tl))
	      (not (cadr tl)))
      (error "%s is not a valid MIME type" type))
    (mm-mailcap-add-mailcap-entry
     (car tl) (cadr tl)
     `((viewer . ,viewer)
       (test . ,(if test test t))
       (type . ,type)))))

;;;
;;; The main whabbo
;;;

(defun mm-mailcap-viewer-lessp (x y)
  ;; Return t iff viewer X is more desirable than viewer Y
  (let ((x-wild (string-match "[*?]" (or (cdr-safe (assq 'type x)) "")))
	(y-wild (string-match "[*?]" (or (cdr-safe (assq 'type y)) "")))
	(x-lisp (not (stringp (or (cdr-safe (assq 'viewer x)) ""))))
	(y-lisp (not (stringp (or (cdr-safe (assq 'viewer y)) "")))))
    (cond
     ((and x-wild (not y-wild))
      nil)
     ((and (not x-wild) y-wild)
      t)
     ((and (not y-lisp) x-lisp)
      t)
     (t nil))))

(defun mm-mailcap-mime-info (string &optional request)
  "Get the MIME viewer command for STRING, return nil if none found.
Expects a complete content-type header line as its argument.

Second argument REQUEST specifies what information to return.  If it is
nil or the empty string, the viewer (second field of the mailcap
entry) will be returned.  If it is a string, then the mailcap field
corresponding to that string will be returned (print, description,
whatever).  If a number, then all the information for this specific
viewer is returned.  If `all', then all possible viewers for
this type is returned."
  (let (
	major				; Major encoding (text, etc)
	minor				; Minor encoding (html, etc)
	info				; Other info
	save-pos			; Misc. position during parse
	major-info			; (assoc major mm-mailcap-mime-data)
	minor-info			; (assoc minor major-info)
	test				; current test proc.
	viewers				; Possible viewers
	passed				; Viewers that passed the test
	viewer				; The one and only viewer
	ctl)
    (save-excursion
      (setq ctl (mail-header-parse-content-type (or string "text/plain")))
      (setq major (if ctl
		      (symbol-name (mime-content-type-primary-type ctl))
		    string))
      (setq minor (and ctl (symbol-name (mime-content-type-subtype ctl))))
      (when (setq major-info (cdr (assoc major mm-mailcap-mime-data)))
	(when (setq viewers (mm-mailcap-possible-viewers major-info minor))
	  (setq info (mapcar (lambda (a) (cons (symbol-name (car a))
					       (cdr a)))
			     (cdr ctl)))
	  (while viewers
	    (if (mm-mailcap-viewer-passes-test (car viewers) info)
		(setq passed (cons (car viewers) passed)))
	    (setq viewers (cdr viewers)))
	  (setq passed (sort (nreverse passed) 'mm-mailcap-viewer-lessp))
	  (setq viewer (car passed))))
      (when (and (stringp (cdr (assq 'viewer viewer)))
		 passed)
	(setq viewer (car passed)))
      (cond
       ((and (null viewer) (not (equal major "default")) request)
	(mm-mailcap-mime-info "default" request))
       ((or (null request) (equal request ""))
	(mm-mailcap-unescape-mime-test (cdr (assq 'viewer viewer)) info))
       ((stringp request)
	(if (or (eq request 'test) (eq request 'viewer))
	    (mm-mailcap-unescape-mime-test
	     (cdr-safe (assoc request viewer)) info)))
       ((eq request 'all)
	passed)
       (t
	;; MUST make a copy *sigh*, else we modify mm-mailcap-mime-data
	(setq viewer (copy-sequence viewer))
	(let ((view (assq 'viewer viewer))
	      (test (assq 'test viewer)))
	  (if view (setcdr view (mm-mailcap-unescape-mime-test (cdr view) info)))
	  (if test (setcdr test (mm-mailcap-unescape-mime-test (cdr test) info))))
	viewer)))))

;;;
;;; Experimental MIME-types parsing
;;;

(defvar mm-mailcap-mime-extensions
  '((""          . "text/plain")
    (".abs"      . "audio/x-mpeg")
    (".aif"      . "audio/aiff")
    (".aifc"     . "audio/aiff")
    (".aiff"     . "audio/aiff")
    (".ano"      . "application/x-annotator")
    (".au"       . "audio/ulaw")
    (".avi"      . "video/x-msvideo")
    (".bcpio"    . "application/x-bcpio")
    (".bin"      . "application/octet-stream")
    (".cdf"      . "application/x-netcdr")
    (".cpio"     . "application/x-cpio")
    (".csh"      . "application/x-csh")
    (".dvi"      . "application/x-dvi")
    (".el"       . "application/emacs-lisp")
    (".eps"      . "application/postscript")
    (".etx"      . "text/x-setext")
    (".exe"      . "application/octet-stream")
    (".fax"      . "image/x-fax")
    (".gif"      . "image/gif")
    (".hdf"      . "application/x-hdf")
    (".hqx"      . "application/mac-binhex40")
    (".htm"      . "text/html")
    (".html"     . "text/html")
    (".icon"     . "image/x-icon")
    (".ief"      . "image/ief")
    (".jpg"      . "image/jpeg")
    (".macp"     . "image/x-macpaint")
    (".man"      . "application/x-troff-man")
    (".me"       . "application/x-troff-me")
    (".mif"      . "application/mif")
    (".mov"      . "video/quicktime")
    (".movie"    . "video/x-sgi-movie")
    (".mp2"      . "audio/x-mpeg")
    (".mp3"      . "audio/x-mpeg")
    (".mp2a"     . "audio/x-mpeg2")
    (".mpa"      . "audio/x-mpeg")
    (".mpa2"     . "audio/x-mpeg2")
    (".mpe"      . "video/mpeg")
    (".mpeg"     . "video/mpeg")
    (".mpega"    . "audio/x-mpeg")
    (".mpegv"    . "video/mpeg")
    (".mpg"      . "video/mpeg")
    (".mpv"      . "video/mpeg")
    (".ms"       . "application/x-troff-ms")
    (".nc"       . "application/x-netcdf")
    (".nc"       . "application/x-netcdf")
    (".oda"      . "application/oda")
    (".patch"    . "text/x-patch")
    (".pbm"      . "image/x-portable-bitmap")
    (".pdf"      . "application/pdf")
    (".pgm"      . "image/portable-graymap")
    (".pict"     . "image/pict")
    (".png"      . "image/png")
    (".pnm"      . "image/x-portable-anymap")
    (".ppm"      . "image/portable-pixmap")
    (".ps"       . "application/postscript")
    (".qt"       . "video/quicktime")
    (".ras"      . "image/x-raster")
    (".rgb"      . "image/x-rgb")
    (".rtf"      . "application/rtf")
    (".rtx"      . "text/richtext")
    (".sh"       . "application/x-sh")
    (".sit"      . "application/x-stuffit")
    (".snd"      . "audio/basic")
    (".src"      . "application/x-wais-source")
    (".tar"      . "archive/tar")
    (".tcl"      . "application/x-tcl")
    (".tcl"      . "application/x-tcl")
    (".tex"      . "application/x-tex")
    (".texi"     . "application/texinfo")
    (".tga"      . "image/x-targa")
    (".tif"      . "image/tiff")
    (".tiff"     . "image/tiff")
    (".tr"       . "application/x-troff")
    (".troff"    . "application/x-troff")
    (".tsv"      . "text/tab-separated-values")
    (".txt"      . "text/plain")
    (".vbs"      . "video/mpeg")
    (".vox"      . "audio/basic")
    (".vrml"     . "x-world/x-vrml")
    (".wav"      . "audio/x-wav")
    (".wrl"      . "x-world/x-vrml")
    (".xbm"      . "image/xbm")
    (".xpm"      . "image/xpm")
    (".xwd"      . "image/windowdump")
    (".zip"      . "application/zip")
    (".ai"       . "application/postscript")
    (".jpe"      . "image/jpeg")
    (".jpeg"     . "image/jpeg"))
  "An assoc list of file extensions and corresponding MIME content-types.")

(defun mm-mailcap-parse-mimetypes (&optional path)
  ;; Parse out all the mimetypes specified in a unix-style path string PATH
  (cond
   (path nil)
   ((getenv "MIMETYPES") (setq path (getenv "MIMETYPES")))
   ((memq system-type '(ms-dos ms-windows windows-nt))
    (setq path (mapconcat 'expand-file-name
			  '("~/mime.typ" "~/etc/mime.typ") ";")))
   (t (setq path (mapconcat 'expand-file-name
			    '("~/.mime-types"
			      "/etc/mime-types:/usr/etc/mime-types"
			      "/usr/local/etc/mime-types"
			      "/usr/local/www/conf/mime-types") ":"))))
  (let ((fnames (reverse
		 (split-string path
			       (if (memq system-type
					 '(ms-dos ms-windows windows-nt))
				   ";" ":"))))
	fname)
    (while fnames
      (setq fname (car fnames))
      (if (and (file-exists-p fname) (file-readable-p fname))
	  (mm-mailcap-parse-mimetype-file (car fnames)))
      (setq fnames (cdr fnames)))))

(defun mm-mailcap-parse-mimetype-file (fname)
  ;; Parse out a mime-types file
  (let (type				; The MIME type for this line
	extns				; The extensions for this line
	save-pos			; Misc. saved buffer positions
	)
    (with-temp-buffer
      (insert-file-contents fname)
      (mm-mailcap-replace-regexp "#.*" "")
      (mm-mailcap-replace-regexp "\n+" "\n")
      (mm-mailcap-replace-regexp "[ \t]+$" "")
      (goto-char (point-max))
      (skip-chars-backward " \t\n")
      (delete-region (point) (point-max))
      (goto-char (point-min))
      (while (not (eobp))
	(skip-chars-forward " \t\n")
	(setq save-pos (point))
	(skip-chars-forward "^ \t")
	(downcase-region save-pos (point))
	(setq type (buffer-substring save-pos (point)))
	(while (not (eolp))
	  (skip-chars-forward " \t")
	  (setq save-pos (point))
	  (skip-chars-forward "^ \t\n")
	  (setq extns (cons (buffer-substring save-pos (point)) extns)))
	(while extns
	  (setq mm-mailcap-mime-extensions
		(cons
		 (cons (if (= (string-to-char (car extns)) ?.)
			   (car extns)
			 (concat "." (car extns))) type)
		 mm-mailcap-mime-extensions)
		extns (cdr extns)))))))

(defun mm-mailcap-extension-to-mime (extn)
  "Return the MIME content type of the file extensions EXTN."
  (if (and (stringp extn)
	   (not (eq (string-to-char extn) ?.)))
      (setq extn (concat "." extn)))
  (cdr (assoc (downcase extn) mm-mailcap-mime-extensions)))

(defvar mm-mailcap-binary-suffixes
  (if (memq system-type '(ms-dos windows-nt))
      '(".exe" ".com" ".bat" ".cmd" ".btm" "")
    '("")))

(defun mm-mailcap-command-p (command)
  "Say whether COMMAND is in the exec path.
The path of COMMAND will be returned iff COMMAND is a command."
  (let ((path (if (file-name-absolute-p command) '(nil) exec-path))
 	file dir)
    (catch 'found
      (while (setq dir (pop path))
	(let ((suffixes mm-mailcap-binary-suffixes))
	  (while suffixes
	    (when (and (file-executable-p
			(setq file (expand-file-name
				    (concat command (pop suffixes))
				    dir)))
		       (not (file-directory-p file)))
	      (throw 'found file))))))))

(defun mm-mailcap-mime-types ()
  "Return a list of MIME media types."
  (mm-delete-duplicates (mapcar 'cdr mm-mailcap-mime-extensions)))

(provide 'mm-mailcap)

;;; mm-mailcap.el ends here