lisp/gnus/mailcap.el

   1 ;;; mailcap.el --- MIME media types configuration
   2
   3 ;; Copyright (C) 1998-2016 Free Software Foundation, Inc.
   4
   5 ;; Author: William M. Perry <wmperry@aventail.com>
   6 ;;      Lars Magne Ingebrigtsen <larsi@gnus.org>
   7 ;; Keywords: news, mail, multimedia
   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 3 of the License, or
  14 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Provides configuration of MIME media types from directly from Lisp
  27 ;; and via the usual mailcap mechanism (RFC 1524).  Deals with
  28 ;; mime.types similarly.
  29
  30 ;;; Code:
  31
  32 (eval-when-compile (require 'cl))
  33 (autoload 'mail-header-parse-content-type "mail-parse")
  34
  35 (defgroup mailcap nil
  36   "Definition of viewers for MIME types."
  37   :version "21.1"
  38   :group 'mime)
  39
  40 (defvar mailcap-parse-args-syntax-table
  41   (let ((table (copy-syntax-table emacs-lisp-mode-syntax-table)))
  42     (modify-syntax-entry ?' "\"" table)
  43     (modify-syntax-entry ?` "\"" table)
  44     (modify-syntax-entry ?{ "(" table)
  45     (modify-syntax-entry ?} ")" table)
  46     table)
  47   "A syntax table for parsing SGML attributes.")
  48
  49 (defvar mailcap-print-command
  50   (mapconcat 'identity
  51              (cons (if (boundp 'lpr-command)
  52                        lpr-command
  53                      "lpr")
  54                    (when (boundp 'lpr-switches)
  55                      (if (stringp lpr-switches)
  56                          (list lpr-switches)
  57                        lpr-switches)))
  58              " ")
  59   "Shell command (including switches) used to print PostScript files.")
  60
  61 ;; Postpone using defcustom for this as it's so big and we essentially
  62 ;; have to have two copies of the data around then.  Perhaps just
  63 ;; customize the Lisp viewers and rely on the normal configuration
  64 ;; files for the rest?  -- fx
  65 (defvar mailcap-mime-data
  66   `(("application"
  67      ("vnd\\.ms-excel"
  68       (viewer . "gnumeric %s")
  69       (test   . (getenv "DISPLAY"))
  70       (type . "application/vnd.ms-excel"))
  71      ("x-x509-ca-cert"
  72       (viewer . ssl-view-site-cert)
  73       (type . "application/x-x509-ca-cert"))
  74      ("x-x509-user-cert"
  75       (viewer . ssl-view-user-cert)
  76       (type . "application/x-x509-user-cert"))
  77      ("octet-stream"
  78       (viewer . mailcap-save-binary-file)
  79       (non-viewer . t)
  80       (type . "application/octet-stream"))
  81      ("dvi"
  82       (viewer . "xdvi -safer %s")
  83       (test   . (eq window-system 'x))
  84       ("needsx11")
  85       (type   . "application/dvi")
  86       ("print" . "dvips -qRP %s"))
  87      ("dvi"
  88       (viewer . "dvitty %s")
  89       (test   . (not (getenv "DISPLAY")))
  90       (type   . "application/dvi")
  91       ("print" . "dvips -qRP %s"))
  92      ("emacs-lisp"
  93       (viewer . mailcap-maybe-eval)
  94       (type   . "application/emacs-lisp"))
  95      ("x-emacs-lisp"
  96       (viewer . mailcap-maybe-eval)
  97       (type   . "application/x-emacs-lisp"))
  98      ("x-tar"
  99       (viewer . mailcap-save-binary-file)
 100       (non-viewer . t)
 101       (type   . "application/x-tar"))
 102      ("x-latex"
 103       (viewer . tex-mode)
 104       (type   . "application/x-latex"))
 105      ("x-tex"
 106       (viewer . tex-mode)
 107       (type   . "application/x-tex"))
 108      ("latex"
 109       (viewer . tex-mode)
 110       (type   . "application/latex"))
 111      ("tex"
 112       (viewer . tex-mode)
 113       (type   . "application/tex"))
 114      ("texinfo"
 115       (viewer . texinfo-mode)
 116       (type   . "application/tex"))
 117      ("zip"
 118       (viewer . mailcap-save-binary-file)
 119       (non-viewer . t)
 120       (type   . "application/zip")
 121       ("copiousoutput"))
 122      ("pdf"
 123       (viewer . pdf-view-mode)
 124       (type . "application/pdf")
 125       (test . (eq window-system 'x)))
 126      ("pdf"
 127       (viewer . doc-view-mode)
 128       (type . "application/pdf")
 129       (test . (eq window-system 'x)))
 130      ("pdf"
 131       (viewer . "gv -safer %s")
 132       (type . "application/pdf")
 133       (test . window-system)
 134       ("print" . ,(concat "pdf2ps %s - | " mailcap-print-command)))
 135      ("pdf"
 136       (viewer . "gpdf %s")
 137       (type . "application/pdf")
 138       ("print" . ,(concat "pdftops %s - | " mailcap-print-command))
 139       (test . (eq window-system 'x)))
 140      ("pdf"
 141       (viewer . "xpdf %s")
 142       (type . "application/pdf")
 143       ("print" . ,(concat "pdftops %s - | " mailcap-print-command))
 144       (test . (eq window-system 'x)))
 145      ("pdf"
 146       (viewer . ,(concat "pdftotext %s -"))
 147       (type   . "application/pdf")
 148       ("print" . ,(concat "pdftops %s - | " mailcap-print-command))
 149       ("copiousoutput"))
 150      ("postscript"
 151       (viewer . "gv -safer %s")
 152       (type . "application/postscript")
 153       (test   . window-system)
 154       ("print" . ,(concat mailcap-print-command " %s"))
 155       ("needsx11"))
 156      ("postscript"
 157       (viewer . "ghostview -dSAFER %s")
 158       (type . "application/postscript")
 159       (test   . (eq window-system 'x))
 160       ("print" . ,(concat mailcap-print-command " %s"))
 161       ("needsx11"))
 162      ("postscript"
 163       (viewer . "ps2ascii %s")
 164       (type . "application/postscript")
 165       (test . (not (getenv "DISPLAY")))
 166       ("print" . ,(concat mailcap-print-command " %s"))
 167       ("copiousoutput"))
 168      ("sieve"
 169       (viewer . sieve-mode)
 170       (type   . "application/sieve"))
 171      ("pgp-keys"
 172       (viewer . "gpg --import --interactive --verbose")
 173       (type   . "application/pgp-keys")
 174       ("needsterminal")))
 175     ("audio"
 176      ("x-mpeg"
 177       (viewer . "maplay %s")
 178       (type   . "audio/x-mpeg"))
 179      (".*"
 180       (viewer . "showaudio")
 181       (type   . "audio/*")))
 182     ("message"
 183      ("rfc-*822"
 184       (viewer . mm-view-message)
 185       (test   . (and (featurep 'gnus)
 186                      (gnus-alive-p)))
 187       (type   . "message/rfc822"))
 188      ("rfc-*822"
 189       (viewer . vm-mode)
 190       (type   . "message/rfc822"))
 191      ("rfc-*822"
 192       (viewer . view-mode)
 193       (type   . "message/rfc822")))
 194     ("image"
 195      ("x-xwd"
 196       (viewer  . "xwud -in %s")
 197       (type    . "image/x-xwd")
 198       ("compose" . "xwd -frame > %s")
 199       (test    . (eq window-system 'x))
 200       ("needsx11"))
 201      ("x11-dump"
 202       (viewer . "xwud -in %s")
 203       (type . "image/x-xwd")
 204       ("compose" . "xwd -frame > %s")
 205       (test   . (eq window-system 'x))
 206       ("needsx11"))
 207      ("windowdump"
 208       (viewer . "xwud -in %s")
 209       (type . "image/x-xwd")
 210       ("compose" . "xwd -frame > %s")
 211       (test   . (eq window-system 'x))
 212       ("needsx11"))
 213      (".*"
 214       (viewer . "display %s")
 215       (type . "image/*")
 216       (test   . (eq window-system 'x))
 217       ("needsx11"))
 218      (".*"
 219       (viewer . "ee %s")
 220       (type . "image/*")
 221       (test   . (eq window-system 'x))
 222       ("needsx11")))
 223     ("text"
 224      ("plain"
 225       (viewer  . view-mode)
 226       (type    . "text/plain"))
 227      ("plain"
 228       (viewer  . fundamental-mode)
 229       (type    . "text/plain"))
 230      ("enriched"
 231       (viewer . enriched-decode)
 232       (type   . "text/enriched"))
 233      ("dns"
 234       (viewer . dns-mode)
 235       (type   . "text/dns")))
 236     ("video"
 237      ("mpeg"
 238       (viewer . "mpeg_play %s")
 239       (type   . "video/mpeg")
 240       (test   . (eq window-system 'x))
 241       ("needsx11")))
 242     ("x-world"
 243      ("x-vrml"
 244       (viewer  . "webspace -remote %s -URL %u")
 245       (type    . "x-world/x-vrml")
 246       ("description"
 247        "VRML document")))
 248     ("archive"
 249      ("tar"
 250       (viewer . tar-mode)
 251       (type . "archive/tar"))))
 252   "The mailcap structure is an assoc list of assoc lists.
 253 1st assoc list is keyed on the major content-type
 254 2nd assoc list is keyed on the minor content-type (which can be a regexp)
 255
 256 Which looks like:
 257 -----------------
 258  ((\"application\"
 259    (\"postscript\" . <info>))
 260   (\"text\"
 261    (\"plain\" . <info>)))
 262
 263 Where <info> is another assoc list of the various information
 264 related to the mailcap RFC 1524.  This is keyed on the lowercase
 265 attribute name (viewer, test, etc).  This looks like:
 266  ((viewer . VIEWERINFO)
 267   (test   . TESTINFO)
 268   (xxxx   . \"STRING\")
 269   FLAG)
 270
 271 Where VIEWERINFO specifies how the content-type is viewed.  Can be
 272 a string, in which case it is run through a shell, with appropriate
 273 parameters, or a symbol, in which case the symbol is `funcall'ed if
 274 and only if it exists as a function, with the buffer as an argument.
 275
 276 TESTINFO is a test for the viewer's applicability, or nil.  If nil, it
 277 means the viewer is always valid.  If it is a Lisp function, it is
 278 called with a list of items from any extra fields from the
 279 Content-Type header as argument to return a boolean value for the
 280 validity.  Otherwise, if it is a non-function Lisp symbol or list
 281 whose car is a symbol, it is `eval'led to yield the validity.  If it
 282 is a string or list of strings, it represents a shell command to run
 283 to return a true or false shell value for the validity.")
 284 (put 'mailcap-mime-data 'risky-local-variable t)
 285
 286 (defcustom mailcap-download-directory nil
 287   "*Directory to which `mailcap-save-binary-file' downloads files by default.
 288 nil means your home directory."
 289   :type '(choice (const :tag "Home directory" nil)
 290                  directory)
 291   :group 'mailcap)
 292
 293 (defvar mailcap-poor-system-types
 294   '(ms-dos windows-nt)
 295   "Systems that don't have a Unix-like directory hierarchy.")
 296
 297 ;;;
 298 ;;; Utility functions
 299 ;;;
 300
 301 (defun mailcap-save-binary-file ()
 302   (goto-char (point-min))
 303   (unwind-protect
 304       (let ((file (read-file-name
 305                    "Filename to save as: "
 306                    (or mailcap-download-directory "~/")))
 307             (require-final-newline nil))
 308         (write-region (point-min) (point-max) file))
 309     (kill-buffer (current-buffer))))
 310
 311 (defvar mailcap-maybe-eval-warning
 312   "*** WARNING ***
 313
 314 This MIME part contains untrusted and possibly harmful content.
 315 If you evaluate the Emacs Lisp code contained in it, a lot of nasty
 316 things can happen.  Please examine the code very carefully before you
 317 instruct Emacs to evaluate it.  You can browse the buffer containing
 318 the code using \\[scroll-other-window].
 319
 320 If you are unsure what to do, please answer \"no\"."
 321   "Text of warning message displayed by `mailcap-maybe-eval'.
 322 Make sure that this text consists only of few text lines.  Otherwise,
 323 Gnus might fail to display all of it.")
 324
 325 (defun mailcap-maybe-eval ()
 326   "Maybe evaluate a buffer of Emacs Lisp code."
 327   (let ((lisp-buffer (current-buffer)))
 328     (goto-char (point-min))
 329     (when
 330         (save-window-excursion
 331           (delete-other-windows)
 332           (let ((buffer (get-buffer-create (generate-new-buffer-name
 333                                             "*Warning*"))))
 334             (unwind-protect
 335                 (with-current-buffer buffer
 336                   (insert (substitute-command-keys
 337                            mailcap-maybe-eval-warning))
 338                   (goto-char (point-min))
 339                   (display-buffer buffer)
 340                   (yes-or-no-p "This is potentially dangerous emacs-lisp code, evaluate it? "))
 341               (kill-buffer buffer))))
 342       (eval-buffer (current-buffer)))
 343     (when (buffer-live-p lisp-buffer)
 344       (with-current-buffer lisp-buffer
 345         (emacs-lisp-mode)))))
 346
 347
 348 ;;;
 349 ;;; The mailcap parser
 350 ;;;
 351
 352 (defun mailcap-replace-regexp (regexp to-string)
 353   ;; Quiet replace-regexp.
 354   (goto-char (point-min))
 355   (while (re-search-forward regexp nil t)
 356     (replace-match to-string t nil)))
 357
 358 (defvar mailcap-parsed-p nil)
 359
 360 (defun mailcap-parse-mailcaps (&optional path force)
 361   "Parse out all the mailcaps specified in a path string PATH.
 362 Components of PATH are separated by the `path-separator' character
 363 appropriate for this system.  If FORCE, re-parse even if already
 364 parsed.  If PATH is omitted, use the value of environment variable
 365 MAILCAPS if set; otherwise (on Unix) use the path from RFC 1524, plus
 366 /usr/local/etc/mailcap."
 367   (interactive (list nil t))
 368   (when (or (not mailcap-parsed-p)
 369             force)
 370     (cond
 371      (path nil)
 372      ((getenv "MAILCAPS") (setq path (getenv "MAILCAPS")))
 373      ((memq system-type mailcap-poor-system-types)
 374       (setq path '("~/.mailcap" "~/mail.cap" "~/etc/mail.cap")))
 375      (t (setq path
 376               ;; This is per RFC 1524, specifically
 377               ;; with /usr before /usr/local.
 378               '("~/.mailcap" "/etc/mailcap" "/usr/etc/mailcap"
 379                 "/usr/local/etc/mailcap"))))
 380     (let ((fnames (reverse
 381                    (if (stringp path)
 382                        (split-string path path-separator t)
 383                      path)))
 384           fname)
 385       (while fnames
 386         (setq fname (car fnames))
 387         (if (and (file-readable-p fname)
 388                  (file-regular-p fname))
 389             (mailcap-parse-mailcap fname))
 390         (setq fnames (cdr fnames))))
 391       (setq mailcap-parsed-p t)))
 392
 393 (defun mailcap-parse-mailcap (fname)
 394   "Parse out the mailcap file specified by FNAME."
 395   (let (major                           ; The major mime type (image/audio/etc)
 396         minor                           ; The minor mime type (gif, basic, etc)
 397         save-pos                        ; Misc saved positions used in parsing
 398         viewer                          ; How to view this mime type
 399         info                            ; Misc info about this mime type
 400         )
 401     (with-temp-buffer
 402       (insert-file-contents fname)
 403       (set-syntax-table mailcap-parse-args-syntax-table)
 404       (mailcap-replace-regexp "#.*" "") ; Remove all comments
 405       (mailcap-replace-regexp "\\\\[ \t]*\n" " ") ; And collapse spaces
 406       (mailcap-replace-regexp "\n+" "\n") ; And blank lines
 407       (goto-char (point-max))
 408       (skip-chars-backward " \t\n")
 409       (delete-region (point) (point-max))
 410       (while (not (bobp))
 411         (skip-chars-backward " \t\n")
 412         (beginning-of-line)
 413         (setq save-pos (point)
 414               info nil)
 415         (skip-chars-forward "^/; \t\n")
 416         (downcase-region save-pos (point))
 417         (setq major (buffer-substring save-pos (point)))
 418         (skip-chars-forward " \t")
 419         (setq minor "")
 420         (when (eq (char-after) ?/)
 421           (forward-char)
 422           (skip-chars-forward " \t")
 423           (setq save-pos (point))
 424           (skip-chars-forward "^; \t\n")
 425           (downcase-region save-pos (point))
 426           (setq minor
 427                 (cond
 428                  ((eq ?* (or (char-after save-pos) 0)) ".*")
 429                  ((= (point) save-pos) ".*")
 430                  (t (regexp-quote (buffer-substring save-pos (point)))))))
 431         (skip-chars-forward " \t")
 432         ;;; Got the major/minor chunks, now for the viewers/etc
 433         ;;; The first item _must_ be a viewer, according to the
 434         ;;; RFC for mailcap files (#1524)
 435         (setq viewer "")
 436         (when (eq (char-after) ?\;)
 437           (forward-char)
 438           (skip-chars-forward " \t")
 439           (setq save-pos (point))
 440           (skip-chars-forward "^;\n")
 441           ;; skip \;
 442           (while (eq (char-before) ?\\)
 443             (backward-delete-char 1)
 444             (forward-char)
 445             (skip-chars-forward "^;\n"))
 446           (if (eq (or (char-after save-pos) 0) ?')
 447               (setq viewer (progn
 448                              (narrow-to-region (1+ save-pos) (point))
 449                              (goto-char (point-min))
 450                              (prog1
 451                                  (read (current-buffer))
 452                                (goto-char (point-max))
 453                                (widen))))
 454             (setq viewer (buffer-substring save-pos (point)))))
 455         (setq save-pos (point))
 456         (end-of-line)
 457         (unless (equal viewer "")
 458           (setq info (nconc (list (cons 'viewer viewer)
 459                                   (cons 'type (concat major "/"
 460                                                       (if (string= minor ".*")
 461                                                           "*" minor))))
 462                             (mailcap-parse-mailcap-extras save-pos (point))))
 463           (mailcap-mailcap-entry-passes-test info)
 464           (mailcap-add-mailcap-entry major minor info))
 465         (beginning-of-line)))))
 466
 467 (defun mailcap-parse-mailcap-extras (st nd)
 468   "Grab all the extra stuff from a mailcap entry."
 469   (let (
 470         name                            ; From name=
 471         value                           ; its value
 472         results                         ; Assoc list of results
 473         name-pos                        ; Start of XXXX= position
 474         val-pos                         ; Start of value position
 475         done                            ; Found end of \'d ;s?
 476         )
 477     (save-restriction
 478       (narrow-to-region st nd)
 479       (goto-char (point-min))
 480       (skip-chars-forward " \n\t;")
 481       (while (not (eobp))
 482         (setq done nil)
 483         (setq name-pos (point))
 484         (skip-chars-forward "^ \n\t=;")
 485         (downcase-region name-pos (point))
 486         (setq name (buffer-substring name-pos (point)))
 487         (skip-chars-forward " \t\n")
 488         (if (not (eq (char-after (point)) ?=)) ; There is no value
 489             (setq value t)
 490           (skip-chars-forward " \t\n=")
 491           (setq val-pos (point))
 492           (if (memq (char-after val-pos) '(?\" ?'))
 493               (progn
 494                 (setq val-pos (1+ val-pos))
 495                 (condition-case nil
 496                     (progn
 497                       (forward-sexp 1)
 498                       (backward-char 1))
 499                   (error (goto-char (point-max)))))
 500             (while (not done)
 501               (skip-chars-forward "^;")
 502               (if (eq (char-after (1- (point))) ?\\ )
 503                   (progn
 504                     (subst-char-in-region (1- (point)) (point) ?\\ ? )
 505                     (skip-chars-forward ";"))
 506                 (setq done t))))
 507           (setq value (buffer-substring val-pos (point))))
 508         ;; `test' as symbol, others like "copiousoutput" and "needsx11" as
 509         ;; strings
 510         (setq results (cons (cons (if (string-equal name "test")
 511                                       'test
 512                                     name)
 513                                   value) results))
 514         (skip-chars-forward " \";\n\t"))
 515       results)))
 516
 517 (defun mailcap-mailcap-entry-passes-test (info)
 518   "Replace the test clause of INFO itself with a boolean for some cases.
 519 This function supports only `test -n $DISPLAY' and `test -z $DISPLAY',
 520 replaces them with t or nil.  As for others or if INFO has a interactive
 521 spec (needsterm, needsterminal, or needsx11) but DISPLAY is not set,
 522 the test clause will be unchanged."
 523   (let ((test (assq 'test info))        ; The test clause
 524         status)
 525     (setq status (and test (split-string (cdr test) " ")))
 526     (if (and (or (assoc "needsterm" info)
 527                  (assoc "needsterminal" info)
 528                  (assoc "needsx11" info))
 529              (not (getenv "DISPLAY")))
 530         (setq status nil)
 531       (cond
 532        ((and (equal (nth 0 status) "test")
 533              (equal (nth 1 status) "-n")
 534              (or (equal (nth 2 status) "$DISPLAY")
 535                  (equal (nth 2 status) "\"$DISPLAY\"")))
 536         (setq status (if (getenv "DISPLAY") t nil)))
 537        ((and (equal (nth 0 status) "test")
 538              (equal (nth 1 status) "-z")
 539              (or (equal (nth 2 status) "$DISPLAY")
 540                  (equal (nth 2 status) "\"$DISPLAY\"")))
 541         (setq status (if (getenv "DISPLAY") nil t)))
 542        (test nil)
 543        (t nil)))
 544     (and test (listp test) (setcdr test status))))
 545
 546 ;;;
 547 ;;; The action routines.
 548 ;;;
 549
 550 (defun mailcap-possible-viewers (major minor)
 551   "Return a list of possible viewers from MAJOR for minor type MINOR."
 552   (let ((exact '())
 553         (wildcard '()))
 554     (while major
 555       (cond
 556        ((equal (car (car major)) minor)
 557         (setq exact (cons (cdr (car major)) exact)))
 558        ((and minor (string-match (concat "^" (car (car major)) "$") minor))
 559         (setq wildcard (cons (cdr (car major)) wildcard))))
 560       (setq major (cdr major)))
 561     (nconc exact wildcard)))
 562
 563 (defun mailcap-unescape-mime-test (test type-info)
 564   (let (save-pos save-chr subst)
 565     (cond
 566      ((symbolp test) test)
 567      ((and (listp test) (symbolp (car test))) test)
 568      ((or (stringp test)
 569           (and (listp test) (stringp (car test))
 570                (setq test (mapconcat 'identity test " "))))
 571       (with-temp-buffer
 572         (insert test)
 573         (goto-char (point-min))
 574         (while (not (eobp))
 575           (skip-chars-forward "^%")
 576           (if (/= (- (point)
 577                      (progn (skip-chars-backward "\\\\")
 578                             (point)))
 579                   0)                    ; It is an escaped %
 580               (progn
 581                 (delete-char 1)
 582                 (skip-chars-forward "%."))
 583             (setq save-pos (point))
 584             (skip-chars-forward "%")
 585             (setq save-chr (char-after (point)))
 586             ;; Escapes:
 587             ;; %s: name of a file for the body data
 588             ;; %t: content-type
 589             ;; %{<parameter name}: value of parameter in mailcap entry
 590             ;; %n: number of sub-parts for multipart content-type
 591             ;; %F: a set of content-type/filename pairs for multiparts
 592             (cond
 593              ((null save-chr) nil)
 594              ((= save-chr ?t)
 595               (delete-region save-pos (progn (forward-char 1) (point)))
 596               (insert (or (cdr (assq 'type type-info)) "\"\"")))
 597              ((memq save-chr '(?M ?n ?F))
 598               (delete-region save-pos (progn (forward-char 1) (point)))
 599               (insert "\"\""))
 600              ((= save-chr ?{)
 601               (forward-char 1)
 602               (skip-chars-forward "^}")
 603               (downcase-region (+ 2 save-pos) (point))
 604               (setq subst (buffer-substring (+ 2 save-pos) (point)))
 605               (delete-region save-pos (1+ (point)))
 606               (insert (or (cdr (assoc subst type-info)) "\"\"")))
 607              (t nil))))
 608         (buffer-string)))
 609      (t (error "Bad value to mailcap-unescape-mime-test: %s" test)))))
 610
 611 (defvar mailcap-viewer-test-cache nil)
 612
 613 (defun mailcap-viewer-passes-test (viewer-info type-info)
 614   "Return non-nil if viewer specified by VIEWER-INFO passes its test clause.
 615 Also return non-nil if it has no test clause.  TYPE-INFO is an argument
 616 to supply to the test."
 617   (let* ((test-info (assq 'test viewer-info))
 618          (test (cdr test-info))
 619          (otest test)
 620          (viewer (cdr (assq 'viewer viewer-info)))
 621          (default-directory (expand-file-name "~/"))
 622          status parsed-test cache result)
 623     (cond ((not (or (stringp viewer) (fboundp viewer)))
 624            nil)                         ; Non-existent Lisp function
 625           ((setq cache (assoc test mailcap-viewer-test-cache))
 626            (cadr cache))
 627           ((not test-info) t)           ; No test clause
 628           (t
 629            (setq
 630             result
 631             (cond
 632              ((not test) nil)           ; Already failed test
 633              ((eq test t) t)            ; Already passed test
 634              ((functionp test)          ; Lisp function as test
 635               (funcall test type-info))
 636              ((and (symbolp test)       ; Lisp variable as test
 637                    (boundp test))
 638               (symbol-value test))
 639              ((and (listp test)         ; List to be eval'd
 640                    (symbolp (car test)))
 641               (eval test))
 642              (t
 643               (setq test (mailcap-unescape-mime-test test type-info)
 644                     test (list shell-file-name nil nil nil
 645                                shell-command-switch test)
 646                     status (apply 'call-process test))
 647               (eq 0 status))))
 648            (push (list otest result) mailcap-viewer-test-cache)
 649            result))))
 650
 651 (defun mailcap-add-mailcap-entry (major minor info)
 652   (let ((old-major (assoc major mailcap-mime-data)))
 653     (if (null old-major)                ; New major area
 654         (setq mailcap-mime-data
 655               (cons (cons major (list (cons minor info)))
 656                     mailcap-mime-data))
 657       (let ((cur-minor (assoc minor old-major)))
 658         (cond
 659          ((or (null cur-minor)          ; New minor area, or
 660               (assq 'test info))        ; Has a test, insert at beginning
 661           (setcdr old-major (cons (cons minor info) (cdr old-major))))
 662          ((and (not (assq 'test info))  ; No test info, replace completely
 663                (not (assq 'test cur-minor))
 664                (equal (assq 'viewer info)  ; Keep alternative viewer
 665                       (assq 'viewer cur-minor)))
 666           (setcdr cur-minor info))
 667          (t
 668           (setcdr old-major (cons (cons minor info) (cdr old-major))))))
 669       )))
 670
 671 (defun mailcap-add (type viewer &optional test)
 672   "Add VIEWER as a handler for TYPE.
 673 If TEST is not given, it defaults to t."
 674   (let ((tl (split-string type "/")))
 675     (when (or (not (car tl))
 676               (not (cadr tl)))
 677       (error "%s is not a valid MIME type" type))
 678     (mailcap-add-mailcap-entry
 679      (car tl) (cadr tl)
 680      `((viewer . ,viewer)
 681        (test . ,(if test test t))
 682        (type . ,type)))))
 683
 684 ;;;
 685 ;;; The main whabbo
 686 ;;;
 687
 688 (defun mailcap-viewer-lessp (x y)
 689   "Return t if viewer X is more desirable than viewer Y."
 690   (let ((x-wild (string-match "[*?]" (or (cdr-safe (assq 'type x)) "")))
 691         (y-wild (string-match "[*?]" (or (cdr-safe (assq 'type y)) "")))
 692         (x-lisp (not (stringp (or (cdr-safe (assq 'viewer x)) ""))))
 693         (y-lisp (not (stringp (or (cdr-safe (assq 'viewer y)) "")))))
 694     (cond
 695      ((and x-wild (not y-wild))
 696       nil)
 697      ((and (not x-wild) y-wild)
 698       t)
 699      ((and (not y-lisp) x-lisp)
 700       t)
 701      (t nil))))
 702
 703 (defun mailcap-mime-info (string &optional request no-decode)
 704   "Get the MIME viewer command for STRING, return nil if none found.
 705 Expects a complete content-type header line as its argument.
 706
 707 Second argument REQUEST specifies what information to return.  If it is
 708 nil or the empty string, the viewer (second field of the mailcap
 709 entry) will be returned.  If it is a string, then the mailcap field
 710 corresponding to that string will be returned (print, description,
 711 whatever).  If a number, then all the information for this specific
 712 viewer is returned.  If `all', then all possible viewers for
 713 this type is returned.
 714
 715 If NO-DECODE is non-nil, don't decode STRING."
 716   ;; NO-DECODE avoids calling `mail-header-parse-content-type' from
 717   ;; `mail-parse.el'
 718   (let (
 719         major                           ; Major encoding (text, etc)
 720         minor                           ; Minor encoding (html, etc)
 721         info                            ; Other info
 722         save-pos                        ; Misc. position during parse
 723         major-info                      ; (assoc major mailcap-mime-data)
 724         minor-info                      ; (assoc minor major-info)
 725         test                            ; current test proc.
 726         viewers                         ; Possible viewers
 727         passed                          ; Viewers that passed the test
 728         viewer                          ; The one and only viewer
 729         ctl)
 730     (save-excursion
 731       (setq ctl
 732             (if no-decode
 733                 (list (or string "text/plain"))
 734               (mail-header-parse-content-type (or string "text/plain"))))
 735       (setq major (split-string (car ctl) "/"))
 736       (setq minor (cadr major)
 737             major (car major))
 738       (when (setq major-info (cdr (assoc major mailcap-mime-data)))
 739         (when (setq viewers (mailcap-possible-viewers major-info minor))
 740           (setq info (mapcar (lambda (a) (cons (symbol-name (car a))
 741                                                (cdr a)))
 742                              (cdr ctl)))
 743           (while viewers
 744             (if (mailcap-viewer-passes-test (car viewers) info)
 745                 (setq passed (cons (car viewers) passed)))
 746             (setq viewers (cdr viewers)))
 747           (setq passed (sort passed 'mailcap-viewer-lessp))
 748           (setq viewer (car passed))))
 749       (when (and (stringp (cdr (assq 'viewer viewer)))
 750                  passed)
 751         (setq viewer (car passed)))
 752       (cond
 753        ((and (null viewer) (not (equal major "default")) request)
 754         (mailcap-mime-info "default" request no-decode))
 755        ((or (null request) (equal request ""))
 756         (mailcap-unescape-mime-test (cdr (assq 'viewer viewer)) info))
 757        ((stringp request)
 758         (mailcap-unescape-mime-test
 759          (cdr-safe (assoc request viewer)) info))
 760        ((eq request 'all)
 761         passed)
 762        (t
 763         ;; MUST make a copy *sigh*, else we modify mailcap-mime-data
 764         (setq viewer (copy-sequence viewer))
 765         (let ((view (assq 'viewer viewer))
 766               (test (assq 'test viewer)))
 767           (if view (setcdr view (mailcap-unescape-mime-test (cdr view) info)))
 768           (if test (setcdr test (mailcap-unescape-mime-test (cdr test) info))))
 769         viewer)))))
 770
 771 ;;;
 772 ;;; Experimental MIME-types parsing
 773 ;;;
 774
 775 (defvar mailcap-mime-extensions
 776   '((""       . "text/plain")
 777     (".1"     . "text/plain")  ;; Manual pages
 778     (".3"     . "text/plain")
 779     (".8"     . "text/plain")
 780     (".abs"   . "audio/x-mpeg")
 781     (".aif"   . "audio/aiff")
 782     (".aifc"  . "audio/aiff")
 783     (".aiff"  . "audio/aiff")
 784     (".ano"   . "application/x-annotator")
 785     (".au"    . "audio/ulaw")
 786     (".avi"   . "video/x-msvideo")
 787     (".bcpio" . "application/x-bcpio")
 788     (".bin"   . "application/octet-stream")
 789     (".cdf"   . "application/x-netcdr")
 790     (".cpio"  . "application/x-cpio")
 791     (".csh"   . "application/x-csh")
 792     (".css"   . "text/css")
 793     (".dvi"   . "application/x-dvi")
 794     (".diff"  . "text/x-patch")
 795     (".dpatch". "test/x-patch")
 796     (".el"    . "application/emacs-lisp")
 797     (".eps"   . "application/postscript")
 798     (".etx"   . "text/x-setext")
 799     (".exe"   . "application/octet-stream")
 800     (".fax"   . "image/x-fax")
 801     (".gif"   . "image/gif")
 802     (".hdf"   . "application/x-hdf")
 803     (".hqx"   . "application/mac-binhex40")
 804     (".htm"   . "text/html")
 805     (".html"  . "text/html")
 806     (".icon"  . "image/x-icon")
 807     (".ief"   . "image/ief")
 808     (".jpg"   . "image/jpeg")
 809     (".macp"  . "image/x-macpaint")
 810     (".man"   . "application/x-troff-man")
 811     (".me"    . "application/x-troff-me")
 812     (".mif"   . "application/mif")
 813     (".mov"   . "video/quicktime")
 814     (".movie" . "video/x-sgi-movie")
 815     (".mp2"   . "audio/x-mpeg")
 816     (".mp3"   . "audio/x-mpeg")
 817     (".mp2a"  . "audio/x-mpeg2")
 818     (".mpa"   . "audio/x-mpeg")
 819     (".mpa2"  . "audio/x-mpeg2")
 820     (".mpe"   . "video/mpeg")
 821     (".mpeg"  . "video/mpeg")
 822     (".mpega" . "audio/x-mpeg")
 823     (".mpegv" . "video/mpeg")
 824     (".mpg"   . "video/mpeg")
 825     (".mpv"   . "video/mpeg")
 826     (".ms"    . "application/x-troff-ms")
 827     (".nc"    . "application/x-netcdf")
 828     (".nc"    . "application/x-netcdf")
 829     (".oda"   . "application/oda")
 830     (".patch" . "text/x-patch")
 831     (".pbm"   . "image/x-portable-bitmap")
 832     (".pdf"   . "application/pdf")
 833     (".pgm"   . "image/portable-graymap")
 834     (".pict"  . "image/pict")
 835     (".png"   . "image/png")
 836     (".pnm"   . "image/x-portable-anymap")
 837     (".pod"   . "text/plain")
 838     (".ppm"   . "image/portable-pixmap")
 839     (".ps"    . "application/postscript")
 840     (".qt"    . "video/quicktime")
 841     (".ras"   . "image/x-raster")
 842     (".rgb"   . "image/x-rgb")
 843     (".rtf"   . "application/rtf")
 844     (".rtx"   . "text/richtext")
 845     (".sh"    . "application/x-sh")
 846     (".sit"   . "application/x-stuffit")
 847     (".siv"   . "application/sieve")
 848     (".snd"   . "audio/basic")
 849     (".soa"   . "text/dns")
 850     (".src"   . "application/x-wais-source")
 851     (".tar"   . "archive/tar")
 852     (".tcl"   . "application/x-tcl")
 853     (".tex"   . "application/x-tex")
 854     (".texi"  . "application/texinfo")
 855     (".tga"   . "image/x-targa")
 856     (".tif"   . "image/tiff")
 857     (".tiff"  . "image/tiff")
 858     (".tr"    . "application/x-troff")
 859     (".troff" . "application/x-troff")
 860     (".tsv"   . "text/tab-separated-values")
 861     (".txt"   . "text/plain")
 862     (".vbs"   . "video/mpeg")
 863     (".vox"   . "audio/basic")
 864     (".vrml"  . "x-world/x-vrml")
 865     (".wav"   . "audio/x-wav")
 866     (".xls"   . "application/vnd.ms-excel")
 867     (".wrl"   . "x-world/x-vrml")
 868     (".xbm"   . "image/xbm")
 869     (".xpm"   . "image/xpm")
 870     (".xwd"   . "image/windowdump")
 871     (".zip"   . "application/zip")
 872     (".ai"    . "application/postscript")
 873     (".jpe"   . "image/jpeg")
 874     (".jpeg"  . "image/jpeg")
 875     (".org"   . "text/x-org"))
 876   "An alist of file extensions and corresponding MIME content-types.
 877 This exists for you to customize the information in Lisp.  It is
 878 merged with values from mailcap files by `mailcap-parse-mimetypes'.")
 879
 880 (defvar mailcap-mimetypes-parsed-p nil)
 881
 882 (defun mailcap-parse-mimetypes (&optional path force)
 883   "Parse out all the mimetypes specified in a Unix-style path string PATH.
 884 Components of PATH are separated by the `path-separator' character
 885 appropriate for this system.  If PATH is omitted, use the value of
 886 environment variable MIMETYPES if set; otherwise use a default path.
 887 If FORCE, re-parse even if already parsed."
 888   (interactive (list nil t))
 889   (when (or (not mailcap-mimetypes-parsed-p)
 890             force)
 891     (cond
 892      (path nil)
 893      ((getenv "MIMETYPES") (setq path (getenv "MIMETYPES")))
 894      ((memq system-type mailcap-poor-system-types)
 895       (setq path '("~/mime.typ" "~/etc/mime.typ")))
 896      (t (setq path
 897               ;; mime.types seems to be the normal name, definitely so
 898               ;; on current GNUish systems.  The search order follows
 899               ;; that for mailcap.
 900               '("~/.mime.types"
 901                 "/etc/mime.types"
 902                 "/usr/etc/mime.types"
 903                 "/usr/local/etc/mime.types"
 904                 "/usr/local/www/conf/mime.types"
 905                 "~/.mime-types"
 906                 "/etc/mime-types"
 907                 "/usr/etc/mime-types"
 908                 "/usr/local/etc/mime-types"
 909                 "/usr/local/www/conf/mime-types"))))
 910     (let ((fnames (reverse (if (stringp path)
 911                                (split-string path path-separator t)
 912                              path)))
 913           fname)
 914       (while fnames
 915         (setq fname (car fnames))
 916         (if (and (file-readable-p fname))
 917             (mailcap-parse-mimetype-file fname))
 918         (setq fnames (cdr fnames))))
 919     (setq mailcap-mimetypes-parsed-p t)))
 920
 921 (defun mailcap-parse-mimetype-file (fname)
 922   "Parse out a mime-types file FNAME."
 923   (let (type                            ; The MIME type for this line
 924         extns                           ; The extensions for this line
 925         save-pos                        ; Misc. saved buffer positions
 926         )
 927     (with-temp-buffer
 928       (insert-file-contents fname)
 929       (mailcap-replace-regexp "#.*" "")
 930       (mailcap-replace-regexp "\n+" "\n")
 931       (mailcap-replace-regexp "[ \t]+$" "")
 932       (goto-char (point-max))
 933       (skip-chars-backward " \t\n")
 934       (delete-region (point) (point-max))
 935       (goto-char (point-min))
 936       (while (not (eobp))
 937         (skip-chars-forward " \t\n")
 938         (setq save-pos (point))
 939         (skip-chars-forward "^ \t\n")
 940         (downcase-region save-pos (point))
 941         (setq type (buffer-substring save-pos (point)))
 942         (while (not (eolp))
 943           (skip-chars-forward " \t")
 944           (setq save-pos (point))
 945           (skip-chars-forward "^ \t\n")
 946           (setq extns (cons (buffer-substring save-pos (point)) extns)))
 947         (while extns
 948           (setq mailcap-mime-extensions
 949                 (cons
 950                  (cons (if (= (string-to-char (car extns)) ?.)
 951                            (car extns)
 952                          (concat "." (car extns))) type)
 953                  mailcap-mime-extensions)
 954                 extns (cdr extns)))))))
 955
 956 (defun mailcap-extension-to-mime (extn)
 957   "Return the MIME content type of the file extensions EXTN."
 958   (mailcap-parse-mimetypes)
 959   (if (and (stringp extn)
 960            (not (eq (string-to-char extn) ?.)))
 961       (setq extn (concat "." extn)))
 962   (cdr (assoc (downcase extn) mailcap-mime-extensions)))
 963
 964 ;; Unused?
 965 (defalias 'mailcap-command-p 'executable-find)
 966
 967 (defun mailcap-mime-types ()
 968   "Return a list of MIME media types."
 969   (mailcap-parse-mimetypes)
 970   (delete-dups
 971    (nconc
 972     (mapcar 'cdr mailcap-mime-extensions)
 973     (apply
 974      'nconc
 975      (mapcar
 976       (lambda (l)
 977         (delq nil
 978               (mapcar
 979                (lambda (m)
 980                  (let ((type (cdr (assq 'type (cdr m)))))
 981                    (if (equal (cadr (split-string type "/"))
 982                               "*")
 983                        nil
 984                      type)))
 985                (cdr l))))
 986       mailcap-mime-data)))))
 987
 988 ;;;
 989 ;;; Useful supplementary functions
 990 ;;;
 991
 992 (defun mailcap-file-default-commands (files)
 993   "Return a list of default commands for FILES."
 994   (mailcap-parse-mailcaps)
 995   (mailcap-parse-mimetypes)
 996   (let* ((all-mime-type
 997           ;; All unique MIME types from file extensions
 998           (delete-dups
 999            (mapcar (lambda (file)
1000                      (mailcap-extension-to-mime
1001                       (file-name-extension file t)))
1002                    files)))
1003          (all-mime-info
1004           ;; All MIME info lists
1005           (delete-dups
1006            (mapcar (lambda (mime-type)
1007                      (mailcap-mime-info mime-type 'all))
1008                    all-mime-type)))
1009          (common-mime-info
1010           ;; Intersection of mime-infos from different mime-types;
1011           ;; or just the first MIME info for a single MIME type
1012           (if (cdr all-mime-info)
1013               (delq nil (mapcar (lambda (mi1)
1014                                   (unless (memq nil (mapcar
1015                                                      (lambda (mi2)
1016                                                        (member mi1 mi2))
1017                                                      (cdr all-mime-info)))
1018                                     mi1))
1019                                 (car all-mime-info)))
1020             (car all-mime-info)))
1021          (commands
1022           ;; Command strings from `viewer' field of the MIME info
1023           (delete-dups
1024            (delq nil (mapcar
1025                       (lambda (mime-info)
1026                         (let ((command (cdr (assoc 'viewer mime-info))))
1027                           (if (stringp command)
1028                               (replace-regexp-in-string
1029                                ;; Replace mailcap's `%s' placeholder
1030                                ;; with dired's `?' placeholder
1031                                "%s" "?"
1032                                (replace-regexp-in-string
1033                                 ;; Remove the final filename placeholder
1034                                 "[ \t\n]*\\('\\)?%s\\1?[ \t\n]*\\'" ""
1035                                 command nil t)
1036                                nil t))))
1037                              common-mime-info)))))
1038     commands))
1039
1040 (defun mailcap-view-mime (type)
1041   "View the data in the current buffer that has MIME type TYPE.
1042 `mailcap-mime-data' determines the method to use."
1043   (let ((method (mailcap-mime-info type)))
1044     (if (stringp method)
1045         (shell-command-on-region (point-min) (point-max)
1046                                  ;; Use stdin as the "%s".
1047                                  (format method "-")
1048                                  (current-buffer)
1049                                  t)
1050       (funcall method))))
1051
1052 (provide 'mailcap)
1053
1054 ;;; mailcap.el ends here