lisp/gnus/mailcap.el

   1 ;;; mailcap.el --- Functions for displaying MIME parts
   2 ;; Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
   3
   4 ;; Author: William M. Perry <wmperry@aventail.com>
   5 ;;      Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; Maintainer: bugs@gnus.org
   7 ;; Keywords: news, mail
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;;; Code:
  29
  30 (eval-when-compile (require 'cl))
  31 (require 'mail-parse)
  32 (require 'mm-util)
  33
  34 (defvar mailcap-parse-args-syntax-table
  35   (let ((table (copy-syntax-table emacs-lisp-mode-syntax-table)))
  36     (modify-syntax-entry ?' "\"" table)
  37     (modify-syntax-entry ?` "\"" table)
  38     (modify-syntax-entry ?{ "(" table)
  39     (modify-syntax-entry ?} ")" table)
  40     table)
  41   "A syntax table for parsing sgml attributes.")
  42
  43 (defvar mailcap-mime-data
  44   '(("application"
  45      ("x-x509-ca-cert"
  46       (viewer . ssl-view-site-cert)
  47       (test . (fboundp 'ssl-view-site-cert))
  48       (type . "application/x-x509-ca-cert"))
  49      ("x-x509-user-cert"
  50       (viewer . ssl-view-user-cert)
  51       (test . (fboundp 'ssl-view-user-cert))
  52       (type . "application/x-x509-user-cert"))
  53      ("octet-stream"
  54       (viewer . mailcap-save-binary-file)
  55       (non-viewer . t)
  56       (type . "application/octet-stream"))
  57      ("dvi"
  58       (viewer . "open %s")
  59       (type   . "application/dvi")
  60       (test   . (eq (mm-device-type) 'ns)))
  61      ("dvi"
  62       (viewer . "xdvi %s")
  63       (test   . (eq (mm-device-type) 'x))
  64       ("needsx11")
  65       (type   . "application/dvi"))
  66      ("dvi"
  67       (viewer . "dvitty %s")
  68       (test   . (not (getenv "DISPLAY")))
  69       (type   . "application/dvi"))
  70      ("emacs-lisp"
  71       (viewer . mailcap-maybe-eval)
  72       (type   . "application/emacs-lisp"))
  73      ("x-tar"
  74       (viewer . mailcap-save-binary-file)
  75       (non-viewer . t)
  76       (type   . "application/x-tar"))
  77      ("x-latex"
  78       (viewer . tex-mode)
  79       (test   . (fboundp 'tex-mode))
  80       (type   . "application/x-latex"))
  81      ("x-tex"
  82       (viewer . tex-mode)
  83       (test   . (fboundp 'tex-mode))
  84       (type   . "application/x-tex"))
  85      ("latex"
  86       (viewer . tex-mode)
  87       (test   . (fboundp 'tex-mode))
  88       (type   . "application/latex"))
  89      ("tex"
  90       (viewer . tex-mode)
  91       (test   . (fboundp 'tex-mode))
  92       (type   . "application/tex"))
  93      ("texinfo"
  94       (viewer . texinfo-mode)
  95       (test   . (fboundp 'texinfo-mode))
  96       (type   . "application/tex"))
  97      ("zip"
  98       (viewer . mailcap-save-binary-file)
  99       (non-viewer . t)
 100       (type   . "application/zip")
 101       ("copiousoutput"))
 102      ("pdf"
 103       (viewer . "acroread %s")
 104       (type   . "application/pdf"))
 105      ("postscript"
 106       (viewer . "open %s")
 107       (type   . "application/postscript")
 108       (test   . (eq (mm-device-type) 'ns)))
 109      ("postscript"
 110       (viewer . "ghostview -dSAFER %s")
 111       (type . "application/postscript")
 112       (test   . (eq (mm-device-type) 'x))
 113       ("needsx11"))
 114      ("postscript"
 115       (viewer . "ps2ascii %s")
 116       (type . "application/postscript")
 117       (test . (not (getenv "DISPLAY")))
 118       ("copiousoutput")))
 119     ("audio"
 120      ("x-mpeg"
 121       (viewer . "maplay %s")
 122       (type   . "audio/x-mpeg"))
 123      (".*"
 124       (viewer . "showaudio")
 125       (type   . "audio/*")))
 126     ("message"
 127      ("rfc-*822"
 128       (viewer . mm-view-message)
 129       (test   . (and (featurep 'gnus)
 130                      (gnus-alive-p)))
 131       (type   . "message/rfc822"))
 132      ("rfc-*822"
 133       (viewer . vm-mode)
 134       (test   . (fboundp 'vm-mode))
 135       (type   . "message/rfc822"))
 136      ("rfc-*822"
 137       (viewer . w3-mode)
 138       (test   . (fboundp 'w3-mode))
 139       (type   . "message/rfc822"))
 140      ("rfc-*822"
 141       (viewer . view-mode)
 142       (test   . (fboundp 'view-mode))
 143       (type   . "message/rfc822"))
 144      ("rfc-*822"
 145       (viewer . fundamental-mode)
 146       (type   . "message/rfc822")))
 147     ("image"
 148      ("x-xwd"
 149       (viewer  . "xwud -in %s")
 150       (type    . "image/x-xwd")
 151       ("compose" . "xwd -frame > %s")
 152       (test    . (eq (mm-device-type) 'x))
 153       ("needsx11"))
 154      ("x11-dump"
 155       (viewer . "xwud -in %s")
 156       (type . "image/x-xwd")
 157       ("compose" . "xwd -frame > %s")
 158       (test   . (eq (mm-device-type) 'x))
 159       ("needsx11"))
 160      ("windowdump"
 161       (viewer . "xwud -in %s")
 162       (type . "image/x-xwd")
 163       ("compose" . "xwd -frame > %s")
 164       (test   . (eq (mm-device-type) 'x))
 165       ("needsx11"))
 166      (".*"
 167       (viewer . "aopen %s")
 168       (type   . "image/*")
 169       (test   . (eq (mm-device-type) 'ns)))
 170      (".*"
 171       (viewer . "display %s")
 172       (type . "image/*")
 173       (test   . (eq (mm-device-type) 'x))
 174       ("needsx11"))
 175      (".*"
 176       (viewer . "ee %s")
 177       (type . "image/*")
 178       (test   . (eq (mm-device-type) 'x))
 179       ("needsx11")))
 180     ("text"
 181      ("plain"
 182       (viewer  . w3-mode)
 183       (test    . (fboundp 'w3-mode))
 184       (type    . "text/plain"))
 185      ("plain"
 186       (viewer  . view-mode)
 187       (test    . (fboundp 'view-mode))
 188       (type    . "text/plain"))
 189      ("plain"
 190       (viewer  . fundamental-mode)
 191       (type    . "text/plain"))
 192      ("enriched"
 193       (viewer . enriched-decode-region)
 194       (test   . (fboundp 'enriched-decode))
 195       (type   . "text/enriched"))
 196      ("html"
 197       (viewer . mm-w3-prepare-buffer)
 198       (test   . (fboundp 'w3-prepare-buffer))
 199       (type   . "text/html")))
 200     ("video"
 201      ("mpeg"
 202       (viewer . "mpeg_play %s")
 203       (type   . "video/mpeg")
 204       (test   . (eq (mm-device-type) 'x))
 205       ("needsx11")))
 206     ("x-world"
 207      ("x-vrml"
 208       (viewer  . "webspace -remote %s -URL %u")
 209       (type    . "x-world/x-vrml")
 210       ("description"
 211        "VRML document")))
 212     ("archive"
 213      ("tar"
 214       (viewer . tar-mode)
 215       (type . "archive/tar")
 216       (test . (fboundp 'tar-mode)))))
 217   "The mailcap structure is an assoc list of assoc lists.
 218 1st assoc list is keyed on the major content-type
 219 2nd assoc list is keyed on the minor content-type (which can be a regexp)
 220
 221 Which looks like:
 222 -----------------
 223  ((\"application\"
 224    (\"postscript\" . <info>))
 225   (\"text\"
 226    (\"plain\" . <info>)))
 227
 228 Where <info> is another assoc list of the various information
 229 related to the mailcap RFC.  This is keyed on the lowercase
 230 attribute name (viewer, test, etc).  This looks like:
 231  ((viewer . viewerinfo)
 232   (test   . testinfo)
 233   (xxxx   . \"string\"))
 234
 235 Where viewerinfo specifies how the content-type is viewed.  Can be
 236 a string, in which case it is run through a shell, with
 237 appropriate parameters, or a symbol, in which case the symbol is
 238 funcall'd, with the buffer as an argument.
 239
 240 testinfo is a list of strings, or nil.  If nil, it means the
 241 viewer specified is always valid.  If it is a list of strings,
 242 these are used to determine whether a viewer passes the 'test' or
 243 not.")
 244
 245 (defvar mailcap-download-directory nil
 246   "*Where downloaded files should go by default.")
 247
 248 (defvar mailcap-temporary-directory
 249   (cond ((fboundp 'temp-directory) (temp-directory))
 250         ((boundp 'temporary-file-directory) temporary-file-directory)
 251         ("/tmp/"))
 252   "*Where temporary files go.")
 253
 254 ;;;
 255 ;;; Utility functions
 256 ;;;
 257
 258 (defun mailcap-generate-unique-filename (&optional fmt)
 259   "Generate a unique filename in mailcap-temporary-directory."
 260   (if (not fmt)
 261       (let ((base (format "mailcap-tmp.%d" (user-real-uid)))
 262             (fname "")
 263             (x 0))
 264         (setq fname (format "%s%d" base x))
 265         (while (file-exists-p
 266                 (expand-file-name fname mailcap-temporary-directory))
 267           (setq x (1+ x)
 268                 fname (concat base (int-to-string x))))
 269         (expand-file-name fname mailcap-temporary-directory))
 270     (let ((base (concat "mm" (int-to-string (user-real-uid))))
 271           (fname "")
 272           (x 0))
 273       (setq fname (format fmt (concat base (int-to-string x))))
 274       (while (file-exists-p
 275               (expand-file-name fname mailcap-temporary-directory))
 276         (setq x (1+ x)
 277               fname (format fmt (concat base (int-to-string x)))))
 278       (expand-file-name fname mailcap-temporary-directory))))
 279
 280 (defun mailcap-save-binary-file ()
 281   (goto-char (point-min))
 282   (unwind-protect
 283       (let ((file (read-file-name
 284                    "Filename to save as: "
 285                    (or mailcap-download-directory "~/")))
 286             (require-final-newline nil))
 287         (write-region (point-min) (point-max) file))
 288     (kill-buffer (current-buffer))))
 289
 290 (defvar mailcap-maybe-eval-warning
 291   "*** WARNING ***
 292
 293 This MIME part contains untrusted and possibly harmful content.
 294 If you evaluate the Emacs Lisp code contained in it, a lot of nasty
 295 things can happen.  Please examine the code very carefully before you
 296 instruct Emacs to evaluate it.  You can browse the buffer containing
 297 the code using \\[scroll-other-window].
 298
 299 If you are unsure what to do, please answer \"no\"."
 300   "Text of warning message displayed by `mailcap-maybe-eval'.
 301 Make sure that this text consists only of few text lines.  Otherwise,
 302 Gnus might fail to display all of it.")
 303
 304 (defun mailcap-maybe-eval ()
 305   "Maybe evaluate a buffer of emacs lisp code."
 306   (let ((lisp-buffer (current-buffer)))
 307     (goto-char (point-min))
 308     (when
 309         (save-window-excursion
 310           (delete-other-windows)
 311           (let ((buffer (get-buffer-create (generate-new-buffer-name
 312                                             "*Warning*"))))
 313             (unwind-protect
 314                 (with-current-buffer buffer
 315                   (insert (substitute-command-keys
 316                            mailcap-maybe-eval-warning))
 317                   (goto-char (point-min))
 318                   (display-buffer buffer)
 319                   (yes-or-no-p "This is potentially dangerous emacs-lisp code, evaluate it? "))
 320               (kill-buffer buffer))))
 321       (eval-buffer (current-buffer)))
 322     (when (buffer-live-p lisp-buffer)
 323       (with-current-buffer lisp-buffer
 324         (emacs-lisp-mode)))))
 325
 326
 327 ;;;
 328 ;;; The mailcap parser
 329 ;;;
 330
 331 (defun mailcap-replace-regexp (regexp to-string)
 332   ;; Quiet replace-regexp.
 333   (goto-char (point-min))
 334   (while (re-search-forward regexp nil t)
 335     (replace-match to-string t nil)))
 336
 337 (defvar mailcap-parsed-p nil)
 338
 339 (defun mailcap-parse-mailcaps (&optional path force)
 340   "Parse out all the mailcaps specified in a path string PATH.
 341 Components of PATH are separated by the `path-separator' character
 342 appropriate for this system.  If FORCE, re-parse even if already
 343 parsed.  If PATH is omitted, use the value of environment variable
 344 MAILCAPS if set; otherwise (on Unix) use the path from RFC 1524, plus
 345 /usr/local/etc/mailcap."
 346   (interactive (list nil t))
 347   (when (or (not mailcap-parsed-p)
 348             force)
 349     (cond
 350      (path nil)
 351      ((getenv "MAILCAPS") (setq path (getenv "MAILCAPS")))
 352      ((memq system-type '(ms-dos ms-windows windows-nt))
 353       (setq path '("~/.mailcap" "~/mail.cap" "~/etc/mail.cap")))
 354      (t (setq path
 355               ;; This is per RFC 1524, specifically
 356               ;; with /usr before /usr/local.
 357               '("~/.mailcap" "/etc/mailcap" "/usr/etc/mailcap"
 358                 "/usr/local/etc/mailcap"))))
 359     (let ((fnames (reverse
 360                    (if (stringp path)
 361                        (delete "" (split-string path path-separator))
 362                      path)))
 363           fname)
 364       (while fnames
 365         (setq fname (car fnames))
 366         (if (and (file-readable-p fname)
 367                  (file-regular-p fname))
 368             (mailcap-parse-mailcap fname))
 369         (setq fnames (cdr fnames))))
 370       (setq mailcap-parsed-p t)))
 371
 372 (defun mailcap-parse-mailcap (fname)
 373   ;; Parse out the mailcap file specified by FNAME
 374   (let (major                           ; The major mime type (image/audio/etc)
 375         minor                           ; The minor mime type (gif, basic, etc)
 376         save-pos                        ; Misc saved positions used in parsing
 377         viewer                          ; How to view this mime type
 378         info                            ; Misc info about this mime type
 379         )
 380     (with-temp-buffer
 381       (insert-file-contents fname)
 382       (set-syntax-table mailcap-parse-args-syntax-table)
 383       (mailcap-replace-regexp "#.*" "") ; Remove all comments
 384       (mailcap-replace-regexp "\\\\[ \t]*\n" " ") ; And collapse spaces
 385       (mailcap-replace-regexp "\n+" "\n") ; And blank lines
 386       (goto-char (point-max))
 387       (skip-chars-backward " \t\n")
 388       (delete-region (point) (point-max))
 389       (while (not (bobp))
 390         (skip-chars-backward " \t\n")
 391         (beginning-of-line)
 392         (setq save-pos (point)
 393               info nil)
 394         (skip-chars-forward "^/; \t\n")
 395         (downcase-region save-pos (point))
 396         (setq major (buffer-substring save-pos (point)))
 397         (skip-chars-forward " \t")
 398         (setq minor "")
 399         (when (eq (char-after) ?/)
 400           (forward-char)
 401           (skip-chars-forward " \t")
 402           (setq save-pos (point))
 403           (skip-chars-forward "^; \t\n")
 404           (downcase-region save-pos (point))
 405           (setq minor
 406                 (cond
 407                  ((eq ?* (or (char-after save-pos) 0)) ".*")
 408                  ((= (point) save-pos) ".*")
 409                  (t (regexp-quote (buffer-substring save-pos (point)))))))
 410         (skip-chars-forward " \t")
 411         ;;; Got the major/minor chunks, now for the viewers/etc
 412         ;;; The first item _must_ be a viewer, according to the
 413         ;;; RFC for mailcap files (#1343)
 414         (setq viewer "")
 415         (when (eq (char-after) ?\;)
 416           (forward-char)
 417           (skip-chars-forward " \t")
 418           (setq save-pos (point))
 419           (skip-chars-forward "^;\n")
 420           ;; skip \;
 421           (while (eq (char-before) ?\\)
 422             (backward-delete-char 1)
 423             (forward-char)
 424             (skip-chars-forward "^;\n"))
 425           (if (eq (or (char-after save-pos) 0) ?')
 426               (setq viewer (progn
 427                              (narrow-to-region (1+ save-pos) (point))
 428                              (goto-char (point-min))
 429                              (prog1
 430                                  (read (current-buffer))
 431                                (goto-char (point-max))
 432                                (widen))))
 433             (setq viewer (buffer-substring save-pos (point)))))
 434         (setq save-pos (point))
 435         (end-of-line)
 436         (unless (equal viewer "")
 437           (setq info (nconc (list (cons 'viewer viewer)
 438                                   (cons 'type (concat major "/"
 439                                                       (if (string= minor ".*")
 440                                                           "*" minor))))
 441                             (mailcap-parse-mailcap-extras save-pos (point))))
 442           (mailcap-mailcap-entry-passes-test info)
 443           (mailcap-add-mailcap-entry major minor info))
 444         (beginning-of-line)))))
 445
 446 (defun mailcap-parse-mailcap-extras (st nd)
 447   ;; Grab all the extra stuff from a mailcap entry
 448   (let (
 449         name                            ; From name=
 450         value                           ; its value
 451         results                         ; Assoc list of results
 452         name-pos                        ; Start of XXXX= position
 453         val-pos                         ; Start of value position
 454         done                            ; Found end of \'d ;s?
 455         )
 456     (save-restriction
 457       (narrow-to-region st nd)
 458       (goto-char (point-min))
 459       (skip-chars-forward " \n\t;")
 460       (while (not (eobp))
 461         (setq done nil)
 462         (setq name-pos (point))
 463         (skip-chars-forward "^ \n\t=;")
 464         (downcase-region name-pos (point))
 465         (setq name (buffer-substring name-pos (point)))
 466         (skip-chars-forward " \t\n")
 467         (if (not (eq (char-after (point)) ?=)) ; There is no value
 468             (setq value t)
 469           (skip-chars-forward " \t\n=")
 470           (setq val-pos (point))
 471           (if (memq (char-after val-pos) '(?\" ?'))
 472               (progn
 473                 (setq val-pos (1+ val-pos))
 474                 (condition-case nil
 475                     (progn
 476                       (forward-sexp 1)
 477                       (backward-char 1))
 478                   (error (goto-char (point-max)))))
 479             (while (not done)
 480               (skip-chars-forward "^;")
 481               (if (eq (char-after (1- (point))) ?\\ )
 482                   (progn
 483                     (subst-char-in-region (1- (point)) (point) ?\\ ? )
 484                     (skip-chars-forward ";"))
 485                 (setq done t))))
 486           (setq value (buffer-substring val-pos (point))))
 487         (setq results (cons (cons name value) results))
 488         (skip-chars-forward " \";\n\t"))
 489       results)))
 490
 491 (defun mailcap-mailcap-entry-passes-test (info)
 492   ;; Return t iff a mailcap entry passes its test clause or no test
 493   ;; clause is present.
 494   (let (status                          ; Call-process-regions return value
 495         (test (assq 'test info))        ; The test clause
 496         )
 497     (setq status (and test (split-string (cdr test) " ")))
 498     (if (and (or (assoc "needsterm" info)
 499                  (assoc "needsterminal" info)
 500                  (assoc "needsx11" info))
 501              (not (getenv "DISPLAY")))
 502         (setq status nil)
 503       (cond
 504        ((and (equal (nth 0 status) "test")
 505              (equal (nth 1 status) "-n")
 506              (or (equal (nth 2 status) "$DISPLAY")
 507                  (equal (nth 2 status) "\"$DISPLAY\"")))
 508         (setq status (if (getenv "DISPLAY") t nil)))
 509        ((and (equal (nth 0 status) "test")
 510              (equal (nth 1 status) "-z")
 511              (or (equal (nth 2 status) "$DISPLAY")
 512                  (equal (nth 2 status) "\"$DISPLAY\"")))
 513         (setq status (if (getenv "DISPLAY") nil t)))
 514        (test nil)
 515        (t nil)))
 516     (and test (listp test) (setcdr test status))))
 517
 518 ;;;
 519 ;;; The action routines.
 520 ;;;
 521
 522 (defun mailcap-possible-viewers (major minor)
 523   ;; Return a list of possible viewers from MAJOR for minor type MINOR
 524   (let ((exact '())
 525         (wildcard '()))
 526     (while major
 527       (cond
 528        ((equal (car (car major)) minor)
 529         (setq exact (cons (cdr (car major)) exact)))
 530        ((and minor (string-match (car (car major)) minor))
 531         (setq wildcard (cons (cdr (car major)) wildcard))))
 532       (setq major (cdr major)))
 533     (nconc exact wildcard)))
 534
 535 (defun mailcap-unescape-mime-test (test type-info)
 536   (let (save-pos save-chr subst)
 537     (cond
 538      ((symbolp test) test)
 539      ((and (listp test) (symbolp (car test))) test)
 540      ((or (stringp test)
 541           (and (listp test) (stringp (car test))
 542                (setq test (mapconcat 'identity test " "))))
 543       (with-temp-buffer
 544         (insert test)
 545         (goto-char (point-min))
 546         (while (not (eobp))
 547           (skip-chars-forward "^%")
 548           (if (/= (- (point)
 549                      (progn (skip-chars-backward "\\\\")
 550                             (point)))
 551                   0)                    ; It is an escaped %
 552               (progn
 553                 (delete-char 1)
 554                 (skip-chars-forward "%."))
 555             (setq save-pos (point))
 556             (skip-chars-forward "%")
 557             (setq save-chr (char-after (point)))
 558             (cond
 559              ((null save-chr) nil)
 560              ((= save-chr ?t)
 561               (delete-region save-pos (progn (forward-char 1) (point)))
 562               (insert (or (cdr (assq 'type type-info)) "\"\"")))
 563              ((= save-chr ?M)
 564               (delete-region save-pos (progn (forward-char 1) (point)))
 565               (insert "\"\""))
 566              ((= save-chr ?n)
 567               (delete-region save-pos (progn (forward-char 1) (point)))
 568               (insert "\"\""))
 569              ((= save-chr ?F)
 570               (delete-region save-pos (progn (forward-char 1) (point)))
 571               (insert "\"\""))
 572              ((= save-chr ?{)
 573               (forward-char 1)
 574               (skip-chars-forward "^}")
 575               (downcase-region (+ 2 save-pos) (point))
 576               (setq subst (buffer-substring (+ 2 save-pos) (point)))
 577               (delete-region save-pos (1+ (point)))
 578               (insert (or (cdr (assoc subst type-info)) "\"\"")))
 579              (t nil))))
 580         (buffer-string)))
 581      (t (error "Bad value to mailcap-unescape-mime-test. %s" test)))))
 582
 583 (defvar mailcap-viewer-test-cache nil)
 584
 585 (defun mailcap-viewer-passes-test (viewer-info type-info)
 586   ;; Return non-nil iff the viewer specified by VIEWER-INFO passes its
 587   ;; test clause (if any).
 588   (let* ((test-info (assq 'test viewer-info))
 589          (test (cdr test-info))
 590          (otest test)
 591          (viewer (cdr (assoc 'viewer viewer-info)))
 592          (default-directory (expand-file-name "~/"))
 593          status parsed-test cache result)
 594     (if (setq cache (assoc test mailcap-viewer-test-cache))
 595         (cadr cache)
 596       (setq
 597        result
 598        (cond
 599         ((not test-info) t)             ; No test clause
 600         ((not test) nil)                ; Already failed test
 601         ((eq test t) t)                 ; Already passed test
 602         ((and (symbolp test)            ; Lisp function as test
 603               (fboundp test))
 604          (funcall test type-info))
 605         ((and (symbolp test)            ; Lisp variable as test
 606               (boundp test))
 607          (symbol-value test))
 608         ((and (listp test)              ; List to be eval'd
 609               (symbolp (car test)))
 610          (eval test))
 611         (t
 612          (setq test (mailcap-unescape-mime-test test type-info)
 613                test (list shell-file-name nil nil nil
 614                           shell-command-switch test)
 615                status (apply 'call-process test))
 616          (= 0 status))))
 617       (push (list otest result) mailcap-viewer-test-cache)
 618       result)))
 619
 620 (defun mailcap-add-mailcap-entry (major minor info)
 621   (let ((old-major (assoc major mailcap-mime-data)))
 622     (if (null old-major)                ; New major area
 623         (setq mailcap-mime-data
 624               (cons (cons major (list (cons minor info)))
 625                     mailcap-mime-data))
 626        (let ((cur-minor (assoc minor old-major)))
 627         (cond
 628          ((or (null cur-minor)          ; New minor area, or
 629               (assq 'test info))        ; Has a test, insert at beginning
 630           (setcdr old-major (cons (cons minor info) (cdr old-major))))
 631          ((and (not (assq 'test info))  ; No test info, replace completely
 632                (not (assq 'test cur-minor))
 633                (equal (assq 'viewer info)  ; Keep alternative viewer
 634                       (assq 'viewer cur-minor)))
 635           (setcdr cur-minor info))
 636          (t
 637           (setcdr old-major (cons (cons minor info) (cdr old-major))))))
 638       )))
 639
 640 (defun mailcap-add (type viewer &optional test)
 641   "Add VIEWER as a handler for TYPE.
 642 If TEST is not given, it defaults to t."
 643   (let ((tl (split-string type "/")))
 644     (when (or (not (car tl))
 645               (not (cadr tl)))
 646       (error "%s is not a valid MIME type" type))
 647     (mailcap-add-mailcap-entry
 648      (car tl) (cadr tl)
 649      `((viewer . ,viewer)
 650        (test . ,(if test test t))
 651        (type . ,type)))))
 652
 653 ;;;
 654 ;;; The main whabbo
 655 ;;;
 656
 657 (defun mailcap-viewer-lessp (x y)
 658   ;; Return t iff viewer X is more desirable than viewer Y
 659   (let ((x-wild (string-match "[*?]" (or (cdr-safe (assq 'type x)) "")))
 660         (y-wild (string-match "[*?]" (or (cdr-safe (assq 'type y)) "")))
 661         (x-lisp (not (stringp (or (cdr-safe (assq 'viewer x)) ""))))
 662         (y-lisp (not (stringp (or (cdr-safe (assq 'viewer y)) "")))))
 663     (cond
 664      ((and x-wild (not y-wild))
 665       nil)
 666      ((and (not x-wild) y-wild)
 667       t)
 668      ((and (not y-lisp) x-lisp)
 669       t)
 670      (t nil))))
 671
 672 (defun mailcap-mime-info (string &optional request)
 673   "Get the MIME viewer command for STRING, return nil if none found.
 674 Expects a complete content-type header line as its argument.
 675
 676 Second argument REQUEST specifies what information to return.  If it is
 677 nil or the empty string, the viewer (second field of the mailcap
 678 entry) will be returned.  If it is a string, then the mailcap field
 679 corresponding to that string will be returned (print, description,
 680 whatever).  If a number, then all the information for this specific
 681 viewer is returned.  If `all', then all possible viewers for
 682 this type is returned."
 683   (let (
 684         major                           ; Major encoding (text, etc)
 685         minor                           ; Minor encoding (html, etc)
 686         info                            ; Other info
 687         save-pos                        ; Misc. position during parse
 688         major-info                      ; (assoc major mailcap-mime-data)
 689         minor-info                      ; (assoc minor major-info)
 690         test                            ; current test proc.
 691         viewers                         ; Possible viewers
 692         passed                          ; Viewers that passed the test
 693         viewer                          ; The one and only viewer
 694         ctl)
 695     (save-excursion
 696       (setq ctl (mail-header-parse-content-type (or string "text/plain")))
 697       (setq major (split-string (car ctl) "/"))
 698       (setq minor (cadr major)
 699             major (car major))
 700       (when (setq major-info (cdr (assoc major mailcap-mime-data)))
 701         (when (setq viewers (mailcap-possible-viewers major-info minor))
 702           (setq info (mapcar (lambda (a) (cons (symbol-name (car a))
 703                                                (cdr a)))
 704                              (cdr ctl)))
 705           (while viewers
 706             (if (mailcap-viewer-passes-test (car viewers) info)
 707                 (setq passed (cons (car viewers) passed)))
 708             (setq viewers (cdr viewers)))
 709           (setq passed (sort passed 'mailcap-viewer-lessp))
 710           (setq viewer (car passed))))
 711       (when (and (stringp (cdr (assq 'viewer viewer)))
 712                  passed)
 713         (setq viewer (car passed)))
 714       (cond
 715        ((and (null viewer) (not (equal major "default")) request)
 716         (mailcap-mime-info "default" request))
 717        ((or (null request) (equal request ""))
 718         (mailcap-unescape-mime-test (cdr (assq 'viewer viewer)) info))
 719        ((stringp request)
 720         (if (or (eq request 'test) (eq request 'viewer))
 721             (mailcap-unescape-mime-test
 722              (cdr-safe (assoc request viewer)) info)))
 723        ((eq request 'all)
 724         passed)
 725        (t
 726         ;; MUST make a copy *sigh*, else we modify mailcap-mime-data
 727         (setq viewer (copy-sequence viewer))
 728         (let ((view (assq 'viewer viewer))
 729               (test (assq 'test viewer)))
 730           (if view (setcdr view (mailcap-unescape-mime-test (cdr view) info)))
 731           (if test (setcdr test (mailcap-unescape-mime-test (cdr test) info))))
 732         viewer)))))
 733
 734 ;;;
 735 ;;; Experimental MIME-types parsing
 736 ;;;
 737
 738 (defvar mailcap-mime-extensions
 739   '((""          . "text/plain")
 740     (".abs"      . "audio/x-mpeg")
 741     (".aif"      . "audio/aiff")
 742     (".aifc"     . "audio/aiff")
 743     (".aiff"     . "audio/aiff")
 744     (".ano"      . "application/x-annotator")
 745     (".au"       . "audio/ulaw")
 746     (".avi"      . "video/x-msvideo")
 747     (".bcpio"    . "application/x-bcpio")
 748     (".bin"      . "application/octet-stream")
 749     (".cdf"      . "application/x-netcdr")
 750     (".cpio"     . "application/x-cpio")
 751     (".csh"      . "application/x-csh")
 752     (".css"      . "text/css")
 753     (".dvi"      . "application/x-dvi")
 754     (".diff"     . "text/x-patch")
 755     (".el"       . "application/emacs-lisp")
 756     (".eps"      . "application/postscript")
 757     (".etx"      . "text/x-setext")
 758     (".exe"      . "application/octet-stream")
 759     (".fax"      . "image/x-fax")
 760     (".gif"      . "image/gif")
 761     (".hdf"      . "application/x-hdf")
 762     (".hqx"      . "application/mac-binhex40")
 763     (".htm"      . "text/html")
 764     (".html"     . "text/html")
 765     (".icon"     . "image/x-icon")
 766     (".ief"      . "image/ief")
 767     (".jpg"      . "image/jpeg")
 768     (".macp"     . "image/x-macpaint")
 769     (".man"      . "application/x-troff-man")
 770     (".me"       . "application/x-troff-me")
 771     (".mif"      . "application/mif")
 772     (".mov"      . "video/quicktime")
 773     (".movie"    . "video/x-sgi-movie")
 774     (".mp2"      . "audio/x-mpeg")
 775     (".mp3"      . "audio/x-mpeg")
 776     (".mp2a"     . "audio/x-mpeg2")
 777     (".mpa"      . "audio/x-mpeg")
 778     (".mpa2"     . "audio/x-mpeg2")
 779     (".mpe"      . "video/mpeg")
 780     (".mpeg"     . "video/mpeg")
 781     (".mpega"    . "audio/x-mpeg")
 782     (".mpegv"    . "video/mpeg")
 783     (".mpg"      . "video/mpeg")
 784     (".mpv"      . "video/mpeg")
 785     (".ms"       . "application/x-troff-ms")
 786     (".nc"       . "application/x-netcdf")
 787     (".nc"       . "application/x-netcdf")
 788     (".oda"      . "application/oda")
 789     (".patch"    . "text/x-patch")
 790     (".pbm"      . "image/x-portable-bitmap")
 791     (".pdf"      . "application/pdf")
 792     (".pgm"      . "image/portable-graymap")
 793     (".pict"     . "image/pict")
 794     (".png"      . "image/png")
 795     (".pnm"      . "image/x-portable-anymap")
 796     (".ppm"      . "image/portable-pixmap")
 797     (".ps"       . "application/postscript")
 798     (".qt"       . "video/quicktime")
 799     (".ras"      . "image/x-raster")
 800     (".rgb"      . "image/x-rgb")
 801     (".rtf"      . "application/rtf")
 802     (".rtx"      . "text/richtext")
 803     (".sh"       . "application/x-sh")
 804     (".sit"      . "application/x-stuffit")
 805     (".snd"      . "audio/basic")
 806     (".src"      . "application/x-wais-source")
 807     (".tar"      . "archive/tar")
 808     (".tcl"      . "application/x-tcl")
 809     (".tcl"      . "application/x-tcl")
 810     (".tex"      . "application/x-tex")
 811     (".texi"     . "application/texinfo")
 812     (".tga"      . "image/x-targa")
 813     (".tif"      . "image/tiff")
 814     (".tiff"     . "image/tiff")
 815     (".tr"       . "application/x-troff")
 816     (".troff"    . "application/x-troff")
 817     (".tsv"      . "text/tab-separated-values")
 818     (".txt"      . "text/plain")
 819     (".vbs"      . "video/mpeg")
 820     (".vox"      . "audio/basic")
 821     (".vrml"     . "x-world/x-vrml")
 822     (".wav"      . "audio/x-wav")
 823     (".wrl"      . "x-world/x-vrml")
 824     (".xbm"      . "image/xbm")
 825     (".xpm"      . "image/xpm")
 826     (".xwd"      . "image/windowdump")
 827     (".zip"      . "application/zip")
 828     (".ai"       . "application/postscript")
 829     (".jpe"      . "image/jpeg")
 830     (".jpeg"     . "image/jpeg"))
 831   "An assoc list of file extensions and corresponding MIME content-types.")
 832
 833 (defvar mailcap-mimetypes-parsed-p nil)
 834
 835 (defun mailcap-parse-mimetypes (&optional path force)
 836   "Parse out all the mimetypes specified in a unix-style path string PATH.
 837 Components of PATH are separated by the `path-separator' character
 838 appropriate for this system.  If PATH is omitted, use the value of
 839 environment variable MIMETYPES if set; otherwise use a default path.
 840 If FORCE, re-parse even if already parsed."
 841   (interactive (list nil t))
 842   (when (or (not mailcap-mimetypes-parsed-p)
 843             force)
 844     (cond
 845      (path nil)
 846      ((getenv "MIMETYPES") (setq path (getenv "MIMETYPES")))
 847      ((memq system-type '(ms-dos ms-windows windows-nt))
 848       (setq path '("~/mime.typ" "~/etc/mime.typ")))
 849      (t (setq path
 850               ;; mime.types seems to be the normal name, definitely so
 851               ;; on current GNUish systems.  The search order follows
 852               ;; that for mailcap.
 853               '("~/.mime.types"
 854                 "/etc/mime.types"
 855                 "/usr/etc/mime.types"
 856                 "/usr/local/etc/mime.types"
 857                 "/usr/local/www/conf/mime.types"
 858                 "~/.mime-types"
 859                 "/etc/mime-types"
 860                 "/usr/etc/mime-types"
 861                 "/usr/local/etc/mime-types"
 862                 "/usr/local/www/conf/mime-types"))))
 863     (let ((fnames (reverse (if (stringp path)
 864                                (delete "" (split-string path path-separator))
 865                              path)))
 866           fname)
 867       (while fnames
 868         (setq fname (car fnames))
 869         (if (and (file-readable-p fname))
 870             (mailcap-parse-mimetype-file fname))
 871         (setq fnames (cdr fnames))))
 872     (setq mailcap-mimetypes-parsed-p t)))
 873
 874 (defun mailcap-parse-mimetype-file (fname)
 875   ;; Parse out a mime-types file
 876   (let (type                            ; The MIME type for this line
 877         extns                           ; The extensions for this line
 878         save-pos                        ; Misc. saved buffer positions
 879         )
 880     (with-temp-buffer
 881       (insert-file-contents fname)
 882       (mailcap-replace-regexp "#.*" "")
 883       (mailcap-replace-regexp "\n+" "\n")
 884       (mailcap-replace-regexp "[ \t]+$" "")
 885       (goto-char (point-max))
 886       (skip-chars-backward " \t\n")
 887       (delete-region (point) (point-max))
 888       (goto-char (point-min))
 889       (while (not (eobp))
 890         (skip-chars-forward " \t\n")
 891         (setq save-pos (point))
 892         (skip-chars-forward "^ \t\n")
 893         (downcase-region save-pos (point))
 894         (setq type (buffer-substring save-pos (point)))
 895         (while (not (eolp))
 896           (skip-chars-forward " \t")
 897           (setq save-pos (point))
 898           (skip-chars-forward "^ \t\n")
 899           (setq extns (cons (buffer-substring save-pos (point)) extns)))
 900         (while extns
 901           (setq mailcap-mime-extensions
 902                 (cons
 903                  (cons (if (= (string-to-char (car extns)) ?.)
 904                            (car extns)
 905                          (concat "." (car extns))) type)
 906                  mailcap-mime-extensions)
 907                 extns (cdr extns)))))))
 908
 909 (defun mailcap-extension-to-mime (extn)
 910   "Return the MIME content type of the file extensions EXTN."
 911   (mailcap-parse-mimetypes)
 912   (if (and (stringp extn)
 913            (not (eq (string-to-char extn) ?.)))
 914       (setq extn (concat "." extn)))
 915   (cdr (assoc (downcase extn) mailcap-mime-extensions)))
 916
 917 (defvar mailcap-binary-suffixes
 918   (if (memq system-type '(ms-dos windows-nt))
 919       '(".exe" ".com" ".bat" ".cmd" ".btm" "")
 920     '("")))
 921
 922 (defun mailcap-command-p (command)
 923   "Say whether COMMAND is in the exec path.
 924 The path of COMMAND will be returned iff COMMAND is a command."
 925   (let ((path (if (file-name-absolute-p command) '(nil) exec-path))
 926         file dir)
 927     (catch 'found
 928       (while (setq dir (pop path))
 929         (let ((suffixes mailcap-binary-suffixes))
 930           (while suffixes
 931             (when (and (file-executable-p
 932                         (setq file (expand-file-name
 933                                     (concat command (pop suffixes))
 934                                     dir)))
 935                        (not (file-directory-p file)))
 936               (throw 'found file))))))))
 937
 938 (defun mailcap-mime-types ()
 939   "Return a list of MIME media types."
 940   (mailcap-parse-mimetypes)
 941   (mm-delete-duplicates
 942    (nconc
 943     (mapcar 'cdr mailcap-mime-extensions)
 944     (apply
 945      'nconc
 946      (mapcar
 947       (lambda (l)
 948         (delq nil
 949               (mapcar
 950                (lambda (m)
 951                  (let ((type (cdr (assq 'type (cdr m)))))
 952                    (if (equal (cadr (split-string type "/"))
 953                               "*")
 954                        nil
 955                      type)))
 956                (cdr l))))
 957       mailcap-mime-data)))))
 958
 959 (provide 'mailcap)
 960
 961 ;;; mailcap.el ends here