lisp/gnus/mailcap.el

   1 ;;; mailcap.el --- MIME media types configuration
   2
   3 ;; Copyright (C) 1998-2014 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 ;; `mm-delete-duplicates' is an alias for `delete-dups' in Emacs 22.
  36 (defalias 'mailcap-delete-duplicates
  37   (if (fboundp 'delete-dups)
  38       'delete-dups
  39     (autoload 'mm-delete-duplicates "mm-util")
  40     'mm-delete-duplicates))
  41
  42 ;; `mailcap-replace-in-string' is an alias like `gnus-replace-in-string'.
  43 (eval-and-compile
  44   (cond
  45    ((fboundp 'replace-regexp-in-string)
  46     (defun mailcap-replace-in-string  (string regexp newtext &optional literal)
  47       "Replace all matches for REGEXP with NEWTEXT in STRING.
  48 If LITERAL is non-nil, insert NEWTEXT literally.  Return a new
  49 string containing the replacements.
  50 This is a compatibility function for different Emacsen."
  51       (replace-regexp-in-string regexp newtext string nil literal)))
  52    ((fboundp 'replace-in-string)
  53     (defalias 'mailcap-replace-in-string 'replace-in-string))))
  54
  55 (defgroup mailcap nil
  56   "Definition of viewers for MIME types."
  57   :version "21.1"
  58   :group 'mime)
  59
  60 (defvar mailcap-parse-args-syntax-table
  61   (let ((table (copy-syntax-table emacs-lisp-mode-syntax-table)))
  62     (modify-syntax-entry ?' "\"" table)
  63     (modify-syntax-entry ?` "\"" table)
  64     (modify-syntax-entry ?{ "(" table)
  65     (modify-syntax-entry ?} ")" table)
  66     table)
  67   "A syntax table for parsing SGML attributes.")
  68
  69 (eval-and-compile
  70   (when (featurep 'xemacs)
  71     (condition-case nil
  72         (require 'lpr)
  73       (error nil))))
  74
  75 (defvar mailcap-print-command
  76   (mapconcat 'identity
  77              (cons (if (boundp 'lpr-command)
  78                        lpr-command
  79                      "lpr")
  80                    (when (boundp 'lpr-switches)
  81                      (if (stringp lpr-switches)
  82                          (list lpr-switches)
  83                        lpr-switches)))
  84              " ")
  85   "Shell command (including switches) used to print PostScript files.")
  86
  87 ;; Postpone using defcustom for this as it's so big and we essentially
  88 ;; have to have two copies of the data around then.  Perhaps just
  89 ;; customize the Lisp viewers and rely on the normal configuration
  90 ;; files for the rest?  -- fx
  91 (defvar mailcap-mime-data
  92   `(("application"
  93      ("vnd\\.ms-excel"
  94       (viewer . "gnumeric %s")
  95       (test   . (getenv "DISPLAY"))
  96       (type . "application/vnd.ms-excel"))
  97      ("x-x509-ca-cert"
  98       (viewer . ssl-view-site-cert)
  99       (test . (fboundp 'ssl-view-site-cert))
 100       (type . "application/x-x509-ca-cert"))
 101      ("x-x509-user-cert"
 102       (viewer . ssl-view-user-cert)
 103       (test . (fboundp 'ssl-view-user-cert))
 104       (type . "application/x-x509-user-cert"))
 105      ("octet-stream"
 106       (viewer . mailcap-save-binary-file)
 107       (non-viewer . t)
 108       (type . "application/octet-stream"))
 109      ("dvi"
 110       (viewer . "xdvi -safer %s")
 111       (test   . (eq window-system 'x))
 112       ("needsx11")
 113       (type   . "application/dvi")
 114       ("print" . "dvips -qRP %s"))
 115      ("dvi"
 116       (viewer . "dvitty %s")
 117       (test   . (not (getenv "DISPLAY")))
 118       (type   . "application/dvi")
 119       ("print" . "dvips -qRP %s"))
 120      ("emacs-lisp"
 121       (viewer . mailcap-maybe-eval)
 122       (type   . "application/emacs-lisp"))
 123      ("x-emacs-lisp"
 124       (viewer . mailcap-maybe-eval)
 125       (type   . "application/x-emacs-lisp"))
 126      ("x-tar"
 127       (viewer . mailcap-save-binary-file)
 128       (non-viewer . t)
 129       (type   . "application/x-tar"))
 130      ("x-latex"
 131       (viewer . tex-mode)
 132       (test   . (fboundp 'tex-mode))
 133       (type   . "application/x-latex"))
 134      ("x-tex"
 135       (viewer . tex-mode)
 136       (test   . (fboundp 'tex-mode))
 137       (type   . "application/x-tex"))
 138      ("latex"
 139       (viewer . tex-mode)
 140       (test   . (fboundp 'tex-mode))
 141       (type   . "application/latex"))
 142      ("tex"
 143       (viewer . tex-mode)
 144       (test   . (fboundp 'tex-mode))
 145       (type   . "application/tex"))
 146      ("texinfo"
 147       (viewer . texinfo-mode)
 148       (test   . (fboundp 'texinfo-mode))
 149       (type   . "application/tex"))
 150      ("zip"
 151       (viewer . mailcap-save-binary-file)
 152       (non-viewer . t)
 153       (type   . "application/zip")
 154       ("copiousoutput"))
 155      ("pdf"
 156       (viewer . "gv -safer %s")
 157       (type . "application/pdf")
 158       (test . window-system)
 159       ("print" . ,(concat "pdf2ps %s - | " mailcap-print-command)))
 160      ("pdf"
 161       (viewer . "gpdf %s")
 162       (type . "application/pdf")
 163       ("print" . ,(concat "pdftops %s - | " mailcap-print-command))
 164       (test . (eq window-system 'x)))
 165      ("pdf"
 166       (viewer . "xpdf %s")
 167       (type . "application/pdf")
 168       ("print" . ,(concat "pdftops %s - | " mailcap-print-command))
 169       (test . (eq window-system 'x)))
 170      ("pdf"
 171       (viewer . ,(concat "pdftotext %s -"))
 172       (type   . "application/pdf")
 173       ("print" . ,(concat "pdftops %s - | " mailcap-print-command))
 174       ("copiousoutput"))
 175      ("postscript"
 176       (viewer . "gv -safer %s")
 177       (type . "application/postscript")
 178       (test   . window-system)
 179       ("print" . ,(concat mailcap-print-command " %s"))
 180       ("needsx11"))
 181      ("postscript"
 182       (viewer . "ghostview -dSAFER %s")
 183       (type . "application/postscript")
 184       (test   . (eq window-system 'x))
 185       ("print" . ,(concat mailcap-print-command " %s"))
 186       ("needsx11"))
 187      ("postscript"
 188       (viewer . "ps2ascii %s")
 189       (type . "application/postscript")
 190       (test . (not (getenv "DISPLAY")))
 191       ("print" . ,(concat mailcap-print-command " %s"))
 192       ("copiousoutput"))
 193      ("sieve"
 194       (viewer . sieve-mode)
 195       (test   . (fboundp 'sieve-mode))
 196       (type   . "application/sieve"))
 197      ("pgp-keys"
 198       (viewer . "gpg --import --interactive --verbose")
 199       (type   . "application/pgp-keys")
 200       ("needsterminal")))
 201     ("audio"
 202      ("x-mpeg"
 203       (viewer . "maplay %s")
 204       (type   . "audio/x-mpeg"))
 205      (".*"
 206       (viewer . "showaudio")
 207       (type   . "audio/*")))
 208     ("message"
 209      ("rfc-*822"
 210       (viewer . mm-view-message)
 211       (test   . (and (featurep 'gnus)
 212                      (gnus-alive-p)))
 213       (type   . "message/rfc822"))
 214      ("rfc-*822"
 215       (viewer . vm-mode)
 216       (test   . (fboundp 'vm-mode))
 217       (type   . "message/rfc822"))
 218      ("rfc-*822"
 219       (viewer . view-mode)
 220       (type   . "message/rfc822")))
 221     ("image"
 222      ("x-xwd"
 223       (viewer  . "xwud -in %s")
 224       (type    . "image/x-xwd")
 225       ("compose" . "xwd -frame > %s")
 226       (test    . (eq window-system 'x))
 227       ("needsx11"))
 228      ("x11-dump"
 229       (viewer . "xwud -in %s")
 230       (type . "image/x-xwd")
 231       ("compose" . "xwd -frame > %s")
 232       (test   . (eq window-system 'x))
 233       ("needsx11"))
 234      ("windowdump"
 235       (viewer . "xwud -in %s")
 236       (type . "image/x-xwd")
 237       ("compose" . "xwd -frame > %s")
 238       (test   . (eq window-system 'x))
 239       ("needsx11"))
 240      (".*"
 241       (viewer . "display %s")
 242       (type . "image/*")
 243       (test   . (eq window-system 'x))
 244       ("needsx11"))
 245      (".*"
 246       (viewer . "ee %s")
 247       (type . "image/*")
 248       (test   . (eq window-system 'x))
 249       ("needsx11")))
 250     ("text"
 251      ("plain"
 252       (viewer  . view-mode)
 253       (test    . (fboundp 'view-mode))
 254       (type    . "text/plain"))
 255      ("plain"
 256       (viewer  . fundamental-mode)
 257       (type    . "text/plain"))
 258      ("enriched"
 259       (viewer . enriched-decode)
 260       (test   . (fboundp 'enriched-decode))
 261       (type   . "text/enriched"))
 262      ("dns"
 263       (viewer . dns-mode)
 264       (test   . (fboundp 'dns-mode))
 265       (type   . "text/dns")))
 266     ("video"
 267      ("mpeg"
 268       (viewer . "mpeg_play %s")
 269       (type   . "video/mpeg")
 270       (test   . (eq window-system 'x))
 271       ("needsx11")))
 272     ("x-world"
 273      ("x-vrml"
 274       (viewer  . "webspace -remote %s -URL %u")
 275       (type    . "x-world/x-vrml")
 276       ("description"
 277        "VRML document")))
 278     ("archive"
 279      ("tar"
 280       (viewer . tar-mode)
 281       (type . "archive/tar")
 282       (test . (fboundp 'tar-mode)))))
 283   "The mailcap structure is an assoc list of assoc lists.
 284 1st assoc list is keyed on the major content-type
 285 2nd assoc list is keyed on the minor content-type (which can be a regexp)
 286
 287 Which looks like:
 288 -----------------
 289  ((\"application\"
 290    (\"postscript\" . <info>))
 291   (\"text\"
 292    (\"plain\" . <info>)))
 293
 294 Where <info> is another assoc list of the various information
 295 related to the mailcap RFC 1524.  This is keyed on the lowercase
 296 attribute name (viewer, test, etc).  This looks like:
 297  ((viewer . VIEWERINFO)
 298   (test   . TESTINFO)
 299   (xxxx   . \"STRING\")
 300   FLAG)
 301
 302 Where VIEWERINFO specifies how the content-type is viewed.  Can be
 303 a string, in which case it is run through a shell, with
 304 appropriate parameters, or a symbol, in which case the symbol is
 305 `funcall'ed, with the buffer as an argument.
 306
 307 TESTINFO is a test for the viewer's applicability, or nil.  If nil, it
 308 means the viewer is always valid.  If it is a Lisp function, it is
 309 called with a list of items from any extra fields from the
 310 Content-Type header as argument to return a boolean value for the
 311 validity.  Otherwise, if it is a non-function Lisp symbol or list
 312 whose car is a symbol, it is `eval'led to yield the validity.  If it
 313 is a string or list of strings, it represents a shell command to run
 314 to return a true or false shell value for the validity.")
 315 (put 'mailcap-mime-data 'risky-local-variable t)
 316
 317 (defcustom mailcap-download-directory nil
 318   "*Directory to which `mailcap-save-binary-file' downloads files by default.
 319 nil means your home directory."
 320   :type '(choice (const :tag "Home directory" nil)
 321                  directory)
 322   :group 'mailcap)
 323
 324 (defvar mailcap-poor-system-types
 325   '(ms-dos windows-nt)
 326   "Systems that don't have a Unix-like directory hierarchy.")
 327
 328 ;;;
 329 ;;; Utility functions
 330 ;;;
 331
 332 (defun mailcap-save-binary-file ()
 333   (goto-char (point-min))
 334   (unwind-protect
 335       (let ((file (read-file-name
 336                    "Filename to save as: "
 337                    (or mailcap-download-directory "~/")))
 338             (require-final-newline nil))
 339         (write-region (point-min) (point-max) file))
 340     (kill-buffer (current-buffer))))
 341
 342 (defvar mailcap-maybe-eval-warning
 343   "*** WARNING ***
 344
 345 This MIME part contains untrusted and possibly harmful content.
 346 If you evaluate the Emacs Lisp code contained in it, a lot of nasty
 347 things can happen.  Please examine the code very carefully before you
 348 instruct Emacs to evaluate it.  You can browse the buffer containing
 349 the code using \\[scroll-other-window].
 350
 351 If you are unsure what to do, please answer \"no\"."
 352   "Text of warning message displayed by `mailcap-maybe-eval'.
 353 Make sure that this text consists only of few text lines.  Otherwise,
 354 Gnus might fail to display all of it.")
 355
 356 (defun mailcap-maybe-eval ()
 357   "Maybe evaluate a buffer of Emacs Lisp code."
 358   (let ((lisp-buffer (current-buffer)))
 359     (goto-char (point-min))
 360     (when
 361         (save-window-excursion
 362           (delete-other-windows)
 363           (let ((buffer (get-buffer-create (generate-new-buffer-name
 364                                             "*Warning*"))))
 365             (unwind-protect
 366                 (with-current-buffer buffer
 367                   (insert (substitute-command-keys
 368                            mailcap-maybe-eval-warning))
 369                   (goto-char (point-min))
 370                   (display-buffer buffer)
 371                   (yes-or-no-p "This is potentially dangerous emacs-lisp code, evaluate it? "))
 372               (kill-buffer buffer))))
 373       (eval-buffer (current-buffer)))
 374     (when (buffer-live-p lisp-buffer)
 375       (with-current-buffer lisp-buffer
 376         (emacs-lisp-mode)))))
 377
 378
 379 ;;;
 380 ;;; The mailcap parser
 381 ;;;
 382
 383 (defun mailcap-replace-regexp (regexp to-string)
 384   ;; Quiet replace-regexp.
 385   (goto-char (point-min))
 386   (while (re-search-forward regexp nil t)
 387     (replace-match to-string t nil)))
 388
 389 (defvar mailcap-parsed-p nil)
 390
 391 (defun mailcap-parse-mailcaps (&optional path force)
 392   "Parse out all the mailcaps specified in a path string PATH.
 393 Components of PATH are separated by the `path-separator' character
 394 appropriate for this system.  If FORCE, re-parse even if already
 395 parsed.  If PATH is omitted, use the value of environment variable
 396 MAILCAPS if set; otherwise (on Unix) use the path from RFC 1524, plus
 397 /usr/local/etc/mailcap."
 398   (interactive (list nil t))
 399   (when (or (not mailcap-parsed-p)
 400             force)
 401     (cond
 402      (path nil)
 403      ((getenv "MAILCAPS") (setq path (getenv "MAILCAPS")))
 404      ((memq system-type mailcap-poor-system-types)
 405       (setq path '("~/.mailcap" "~/mail.cap" "~/etc/mail.cap")))
 406      (t (setq path
 407               ;; This is per RFC 1524, specifically
 408               ;; with /usr before /usr/local.
 409               '("~/.mailcap" "/etc/mailcap" "/usr/etc/mailcap"
 410                 "/usr/local/etc/mailcap"))))
 411     (let ((fnames (reverse
 412                    (if (stringp path)
 413                        (split-string path path-separator t)
 414                      path)))
 415           fname)
 416       (while fnames
 417         (setq fname (car fnames))
 418         (if (and (file-readable-p fname)
 419                  (file-regular-p fname))
 420             (mailcap-parse-mailcap fname))
 421         (setq fnames (cdr fnames))))
 422       (setq mailcap-parsed-p t)))
 423
 424 (defun mailcap-parse-mailcap (fname)
 425   "Parse out the mailcap file specified by FNAME."
 426   (let (major                           ; The major mime type (image/audio/etc)
 427         minor                           ; The minor mime type (gif, basic, etc)
 428         save-pos                        ; Misc saved positions used in parsing
 429         viewer                          ; How to view this mime type
 430         info                            ; Misc info about this mime type
 431         )
 432     (with-temp-buffer
 433       (insert-file-contents fname)
 434       (set-syntax-table mailcap-parse-args-syntax-table)
 435       (mailcap-replace-regexp "#.*" "") ; Remove all comments
 436       (mailcap-replace-regexp "\\\\[ \t]*\n" " ") ; And collapse spaces
 437       (mailcap-replace-regexp "\n+" "\n") ; And blank lines
 438       (goto-char (point-max))
 439       (skip-chars-backward " \t\n")
 440       (delete-region (point) (point-max))
 441       (while (not (bobp))
 442         (skip-chars-backward " \t\n")
 443         (beginning-of-line)
 444         (setq save-pos (point)
 445               info nil)
 446         (skip-chars-forward "^/; \t\n")
 447         (downcase-region save-pos (point))
 448         (setq major (buffer-substring save-pos (point)))
 449         (skip-chars-forward " \t")
 450         (setq minor "")
 451         (when (eq (char-after) ?/)
 452           (forward-char)
 453           (skip-chars-forward " \t")
 454           (setq save-pos (point))
 455           (skip-chars-forward "^; \t\n")
 456           (downcase-region save-pos (point))
 457           (setq minor
 458                 (cond
 459                  ((eq ?* (or (char-after save-pos) 0)) ".*")
 460                  ((= (point) save-pos) ".*")
 461                  (t (regexp-quote (buffer-substring save-pos (point)))))))
 462         (skip-chars-forward " \t")
 463         ;;; Got the major/minor chunks, now for the viewers/etc
 464         ;;; The first item _must_ be a viewer, according to the
 465         ;;; RFC for mailcap files (#1524)
 466         (setq viewer "")
 467         (when (eq (char-after) ?\;)
 468           (forward-char)
 469           (skip-chars-forward " \t")
 470           (setq save-pos (point))
 471           (skip-chars-forward "^;\n")
 472           ;; skip \;
 473           (while (eq (char-before) ?\\)
 474             (backward-delete-char 1)
 475             (forward-char)
 476             (skip-chars-forward "^;\n"))
 477           (if (eq (or (char-after save-pos) 0) ?')
 478               (setq viewer (progn
 479                              (narrow-to-region (1+ save-pos) (point))
 480                              (goto-char (point-min))
 481                              (prog1
 482                                  (read (current-buffer))
 483                                (goto-char (point-max))
 484                                (widen))))
 485             (setq viewer (buffer-substring save-pos (point)))))
 486         (setq save-pos (point))
 487         (end-of-line)
 488         (unless (equal viewer "")
 489           (setq info (nconc (list (cons 'viewer viewer)
 490                                   (cons 'type (concat major "/"
 491                                                       (if (string= minor ".*")
 492                                                           "*" minor))))
 493                             (mailcap-parse-mailcap-extras save-pos (point))))
 494           (mailcap-mailcap-entry-passes-test info)
 495           (mailcap-add-mailcap-entry major minor info))
 496         (beginning-of-line)))))
 497
 498 (defun mailcap-parse-mailcap-extras (st nd)
 499   "Grab all the extra stuff from a mailcap entry."
 500   (let (
 501         name                            ; From name=
 502         value                           ; its value
 503         results                         ; Assoc list of results
 504         name-pos                        ; Start of XXXX= position
 505         val-pos                         ; Start of value position
 506         done                            ; Found end of \'d ;s?
 507         )
 508     (save-restriction
 509       (narrow-to-region st nd)
 510       (goto-char (point-min))
 511       (skip-chars-forward " \n\t;")
 512       (while (not (eobp))
 513         (setq done nil)
 514         (setq name-pos (point))
 515         (skip-chars-forward "^ \n\t=;")
 516         (downcase-region name-pos (point))
 517         (setq name (buffer-substring name-pos (point)))
 518         (skip-chars-forward " \t\n")
 519         (if (not (eq (char-after (point)) ?=)) ; There is no value
 520             (setq value t)
 521           (skip-chars-forward " \t\n=")
 522           (setq val-pos (point))
 523           (if (memq (char-after val-pos) '(?\" ?'))
 524               (progn
 525                 (setq val-pos (1+ val-pos))
 526                 (condition-case nil
 527                     (progn
 528                       (forward-sexp 1)
 529                       (backward-char 1))
 530                   (error (goto-char (point-max)))))
 531             (while (not done)
 532               (skip-chars-forward "^;")
 533               (if (eq (char-after (1- (point))) ?\\ )
 534                   (progn
 535                     (subst-char-in-region (1- (point)) (point) ?\\ ? )
 536                     (skip-chars-forward ";"))
 537                 (setq done t))))
 538           (setq value (buffer-substring val-pos (point))))
 539         ;; `test' as symbol, others like "copiousoutput" and "needsx11" as
 540         ;; strings
 541         (setq results (cons (cons (if (string-equal name "test")
 542                                       'test
 543                                     name)
 544                                   value) results))
 545         (skip-chars-forward " \";\n\t"))
 546       results)))
 547
 548 (defun mailcap-mailcap-entry-passes-test (info)
 549   "Return non-nil if mailcap entry INFO passes its test clause.
 550 Also return non-nil if no test clause is present."
 551   (let ((test (assq 'test info))        ; The test clause
 552         status)
 553     (setq status (and test (split-string (cdr test) " ")))
 554     (if (and (or (assoc "needsterm" info)
 555                  (assoc "needsterminal" info)
 556                  (assoc "needsx11" info))
 557              (not (getenv "DISPLAY")))
 558         (setq status nil)
 559       (cond
 560        ((and (equal (nth 0 status) "test")
 561              (equal (nth 1 status) "-n")
 562              (or (equal (nth 2 status) "$DISPLAY")
 563                  (equal (nth 2 status) "\"$DISPLAY\"")))
 564         (setq status (if (getenv "DISPLAY") t nil)))
 565        ((and (equal (nth 0 status) "test")
 566              (equal (nth 1 status) "-z")
 567              (or (equal (nth 2 status) "$DISPLAY")
 568                  (equal (nth 2 status) "\"$DISPLAY\"")))
 569         (setq status (if (getenv "DISPLAY") nil t)))
 570        (test nil)
 571        (t nil)))
 572     (and test (listp test) (setcdr test status))))
 573
 574 ;;;
 575 ;;; The action routines.
 576 ;;;
 577
 578 (defun mailcap-possible-viewers (major minor)
 579   "Return a list of possible viewers from MAJOR for minor type MINOR."
 580   (let ((exact '())
 581         (wildcard '()))
 582     (while major
 583       (cond
 584        ((equal (car (car major)) minor)
 585         (setq exact (cons (cdr (car major)) exact)))
 586        ((and minor (string-match (concat "^" (car (car major)) "$") minor))
 587         (setq wildcard (cons (cdr (car major)) wildcard))))
 588       (setq major (cdr major)))
 589     (nconc exact wildcard)))
 590
 591 (defun mailcap-unescape-mime-test (test type-info)
 592   (let (save-pos save-chr subst)
 593     (cond
 594      ((symbolp test) test)
 595      ((and (listp test) (symbolp (car test))) test)
 596      ((or (stringp test)
 597           (and (listp test) (stringp (car test))
 598                (setq test (mapconcat 'identity test " "))))
 599       (with-temp-buffer
 600         (insert test)
 601         (goto-char (point-min))
 602         (while (not (eobp))
 603           (skip-chars-forward "^%")
 604           (if (/= (- (point)
 605                      (progn (skip-chars-backward "\\\\")
 606                             (point)))
 607                   0)                    ; It is an escaped %
 608               (progn
 609                 (delete-char 1)
 610                 (skip-chars-forward "%."))
 611             (setq save-pos (point))
 612             (skip-chars-forward "%")
 613             (setq save-chr (char-after (point)))
 614             ;; Escapes:
 615             ;; %s: name of a file for the body data
 616             ;; %t: content-type
 617             ;; %{<parameter name}: value of parameter in mailcap entry
 618             ;; %n: number of sub-parts for multipart content-type
 619             ;; %F: a set of content-type/filename pairs for multiparts
 620             (cond
 621              ((null save-chr) nil)
 622              ((= save-chr ?t)
 623               (delete-region save-pos (progn (forward-char 1) (point)))
 624               (insert (or (cdr (assq 'type type-info)) "\"\"")))
 625              ((memq save-chr '(?M ?n ?F))
 626               (delete-region save-pos (progn (forward-char 1) (point)))
 627               (insert "\"\""))
 628              ((= save-chr ?{)
 629               (forward-char 1)
 630               (skip-chars-forward "^}")
 631               (downcase-region (+ 2 save-pos) (point))
 632               (setq subst (buffer-substring (+ 2 save-pos) (point)))
 633               (delete-region save-pos (1+ (point)))
 634               (insert (or (cdr (assoc subst type-info)) "\"\"")))
 635              (t nil))))
 636         (buffer-string)))
 637      (t (error "Bad value to mailcap-unescape-mime-test: %s" test)))))
 638
 639 (defvar mailcap-viewer-test-cache nil)
 640
 641 (defun mailcap-viewer-passes-test (viewer-info type-info)
 642   "Return non-nil if viewer specified by VIEWER-INFO passes its test clause.
 643 Also return non-nil if it has no test clause.  TYPE-INFO is an argument
 644 to supply to the test."
 645   (let* ((test-info (assq 'test viewer-info))
 646          (test (cdr test-info))
 647          (otest test)
 648          (viewer (cdr (assoc 'viewer viewer-info)))
 649          (default-directory (expand-file-name "~/"))
 650          status parsed-test cache result)
 651     (cond ((setq cache (assoc test mailcap-viewer-test-cache))
 652            (cadr cache))
 653           ((not test-info) t)           ; No test clause
 654           (t
 655            (setq
 656             result
 657             (cond
 658              ((not test) nil)           ; Already failed test
 659              ((eq test t) t)            ; Already passed test
 660              ((functionp test)          ; Lisp function as test
 661               (funcall test type-info))
 662              ((and (symbolp test)       ; Lisp variable as test
 663                    (boundp test))
 664               (symbol-value test))
 665              ((and (listp test)         ; List to be eval'd
 666                    (symbolp (car test)))
 667               (eval test))
 668              (t
 669               (setq test (mailcap-unescape-mime-test test type-info)
 670                     test (list shell-file-name nil nil nil
 671                                shell-command-switch test)
 672                     status (apply 'call-process test))
 673               (eq 0 status))))
 674            (push (list otest result) mailcap-viewer-test-cache)
 675            result))))
 676
 677 (defun mailcap-add-mailcap-entry (major minor info)
 678   (let ((old-major (assoc major mailcap-mime-data)))
 679     (if (null old-major)                ; New major area
 680         (setq mailcap-mime-data
 681               (cons (cons major (list (cons minor info)))
 682                     mailcap-mime-data))
 683       (let ((cur-minor (assoc minor old-major)))
 684         (cond
 685          ((or (null cur-minor)          ; New minor area, or
 686               (assq 'test info))        ; Has a test, insert at beginning
 687           (setcdr old-major (cons (cons minor info) (cdr old-major))))
 688          ((and (not (assq 'test info))  ; No test info, replace completely
 689                (not (assq 'test cur-minor))
 690                (equal (assq 'viewer info)  ; Keep alternative viewer
 691                       (assq 'viewer cur-minor)))
 692           (setcdr cur-minor info))
 693          (t
 694           (setcdr old-major (cons (cons minor info) (cdr old-major))))))
 695       )))
 696
 697 (defun mailcap-add (type viewer &optional test)
 698   "Add VIEWER as a handler for TYPE.
 699 If TEST is not given, it defaults to t."
 700   (let ((tl (split-string type "/")))
 701     (when (or (not (car tl))
 702               (not (cadr tl)))
 703       (error "%s is not a valid MIME type" type))
 704     (mailcap-add-mailcap-entry
 705      (car tl) (cadr tl)
 706      `((viewer . ,viewer)
 707        (test . ,(if test test t))
 708        (type . ,type)))))
 709
 710 ;;;
 711 ;;; The main whabbo
 712 ;;;
 713
 714 (defun mailcap-viewer-lessp (x y)
 715   "Return t if viewer X is more desirable than viewer Y."
 716   (let ((x-wild (string-match "[*?]" (or (cdr-safe (assq 'type x)) "")))
 717         (y-wild (string-match "[*?]" (or (cdr-safe (assq 'type y)) "")))
 718         (x-lisp (not (stringp (or (cdr-safe (assq 'viewer x)) ""))))
 719         (y-lisp (not (stringp (or (cdr-safe (assq 'viewer y)) "")))))
 720     (cond
 721      ((and x-wild (not y-wild))
 722       nil)
 723      ((and (not x-wild) y-wild)
 724       t)
 725      ((and (not y-lisp) x-lisp)
 726       t)
 727      (t nil))))
 728
 729 (defun mailcap-mime-info (string &optional request no-decode)
 730   "Get the MIME viewer command for STRING, return nil if none found.
 731 Expects a complete content-type header line as its argument.
 732
 733 Second argument REQUEST specifies what information to return.  If it is
 734 nil or the empty string, the viewer (second field of the mailcap
 735 entry) will be returned.  If it is a string, then the mailcap field
 736 corresponding to that string will be returned (print, description,
 737 whatever).  If a number, then all the information for this specific
 738 viewer is returned.  If `all', then all possible viewers for
 739 this type is returned.
 740
 741 If NO-DECODE is non-nil, don't decode STRING."
 742   ;; NO-DECODE avoids calling `mail-header-parse-content-type' from
 743   ;; `mail-parse.el'
 744   (let (
 745         major                           ; Major encoding (text, etc)
 746         minor                           ; Minor encoding (html, etc)
 747         info                            ; Other info
 748         save-pos                        ; Misc. position during parse
 749         major-info                      ; (assoc major mailcap-mime-data)
 750         minor-info                      ; (assoc minor major-info)
 751         test                            ; current test proc.
 752         viewers                         ; Possible viewers
 753         passed                          ; Viewers that passed the test
 754         viewer                          ; The one and only viewer
 755         ctl)
 756     (save-excursion
 757       (setq ctl
 758             (if no-decode
 759                 (list (or string "text/plain"))
 760               (mail-header-parse-content-type (or string "text/plain"))))
 761       (setq major (split-string (car ctl) "/"))
 762       (setq minor (cadr major)
 763             major (car major))
 764       (when (setq major-info (cdr (assoc major mailcap-mime-data)))
 765         (when (setq viewers (mailcap-possible-viewers major-info minor))
 766           (setq info (mapcar (lambda (a) (cons (symbol-name (car a))
 767                                                (cdr a)))
 768                              (cdr ctl)))
 769           (while viewers
 770             (if (mailcap-viewer-passes-test (car viewers) info)
 771                 (setq passed (cons (car viewers) passed)))
 772             (setq viewers (cdr viewers)))
 773           (setq passed (sort passed 'mailcap-viewer-lessp))
 774           (setq viewer (car passed))))
 775       (when (and (stringp (cdr (assq 'viewer viewer)))
 776                  passed)
 777         (setq viewer (car passed)))
 778       (cond
 779        ((and (null viewer) (not (equal major "default")) request)
 780         (mailcap-mime-info "default" request no-decode))
 781        ((or (null request) (equal request ""))
 782         (mailcap-unescape-mime-test (cdr (assq 'viewer viewer)) info))
 783        ((stringp request)
 784         (mailcap-unescape-mime-test
 785          (cdr-safe (assoc request viewer)) info))
 786        ((eq request 'all)
 787         passed)
 788        (t
 789         ;; MUST make a copy *sigh*, else we modify mailcap-mime-data
 790         (setq viewer (copy-sequence viewer))
 791         (let ((view (assq 'viewer viewer))
 792               (test (assq 'test viewer)))
 793           (if view (setcdr view (mailcap-unescape-mime-test (cdr view) info)))
 794           (if test (setcdr test (mailcap-unescape-mime-test (cdr test) info))))
 795         viewer)))))
 796
 797 ;;;
 798 ;;; Experimental MIME-types parsing
 799 ;;;
 800
 801 (defvar mailcap-mime-extensions
 802   '((""       . "text/plain")
 803     (".1"     . "text/plain")  ;; Manual pages
 804     (".3"     . "text/plain")
 805     (".8"     . "text/plain")
 806     (".abs"   . "audio/x-mpeg")
 807     (".aif"   . "audio/aiff")
 808     (".aifc"  . "audio/aiff")
 809     (".aiff"  . "audio/aiff")
 810     (".ano"   . "application/x-annotator")
 811     (".au"    . "audio/ulaw")
 812     (".avi"   . "video/x-msvideo")
 813     (".bcpio" . "application/x-bcpio")
 814     (".bin"   . "application/octet-stream")
 815     (".cdf"   . "application/x-netcdr")
 816     (".cpio"  . "application/x-cpio")
 817     (".csh"   . "application/x-csh")
 818     (".css"   . "text/css")
 819     (".dvi"   . "application/x-dvi")
 820     (".diff"  . "text/x-patch")
 821     (".dpatch". "test/x-patch")
 822     (".el"    . "application/emacs-lisp")
 823     (".eps"   . "application/postscript")
 824     (".etx"   . "text/x-setext")
 825     (".exe"   . "application/octet-stream")
 826     (".fax"   . "image/x-fax")
 827     (".gif"   . "image/gif")
 828     (".hdf"   . "application/x-hdf")
 829     (".hqx"   . "application/mac-binhex40")
 830     (".htm"   . "text/html")
 831     (".html"  . "text/html")
 832     (".icon"  . "image/x-icon")
 833     (".ief"   . "image/ief")
 834     (".jpg"   . "image/jpeg")
 835     (".macp"  . "image/x-macpaint")
 836     (".man"   . "application/x-troff-man")
 837     (".me"    . "application/x-troff-me")
 838     (".mif"   . "application/mif")
 839     (".mov"   . "video/quicktime")
 840     (".movie" . "video/x-sgi-movie")
 841     (".mp2"   . "audio/x-mpeg")
 842     (".mp3"   . "audio/x-mpeg")
 843     (".mp2a"  . "audio/x-mpeg2")
 844     (".mpa"   . "audio/x-mpeg")
 845     (".mpa2"  . "audio/x-mpeg2")
 846     (".mpe"   . "video/mpeg")
 847     (".mpeg"  . "video/mpeg")
 848     (".mpega" . "audio/x-mpeg")
 849     (".mpegv" . "video/mpeg")
 850     (".mpg"   . "video/mpeg")
 851     (".mpv"   . "video/mpeg")
 852     (".ms"    . "application/x-troff-ms")
 853     (".nc"    . "application/x-netcdf")
 854     (".nc"    . "application/x-netcdf")
 855     (".oda"   . "application/oda")
 856     (".patch" . "text/x-patch")
 857     (".pbm"   . "image/x-portable-bitmap")
 858     (".pdf"   . "application/pdf")
 859     (".pgm"   . "image/portable-graymap")
 860     (".pict"  . "image/pict")
 861     (".png"   . "image/png")
 862     (".pnm"   . "image/x-portable-anymap")
 863     (".pod"   . "text/plain")
 864     (".ppm"   . "image/portable-pixmap")
 865     (".ps"    . "application/postscript")
 866     (".qt"    . "video/quicktime")
 867     (".ras"   . "image/x-raster")
 868     (".rgb"   . "image/x-rgb")
 869     (".rtf"   . "application/rtf")
 870     (".rtx"   . "text/richtext")
 871     (".sh"    . "application/x-sh")
 872     (".sit"   . "application/x-stuffit")
 873     (".siv"   . "application/sieve")
 874     (".snd"   . "audio/basic")
 875     (".soa"   . "text/dns")
 876     (".src"   . "application/x-wais-source")
 877     (".tar"   . "archive/tar")
 878     (".tcl"   . "application/x-tcl")
 879     (".tex"   . "application/x-tex")
 880     (".texi"  . "application/texinfo")
 881     (".tga"   . "image/x-targa")
 882     (".tif"   . "image/tiff")
 883     (".tiff"  . "image/tiff")
 884     (".tr"    . "application/x-troff")
 885     (".troff" . "application/x-troff")
 886     (".tsv"   . "text/tab-separated-values")
 887     (".txt"   . "text/plain")
 888     (".vbs"   . "video/mpeg")
 889     (".vox"   . "audio/basic")
 890     (".vrml"  . "x-world/x-vrml")
 891     (".wav"   . "audio/x-wav")
 892     (".xls"   . "application/vnd.ms-excel")
 893     (".wrl"   . "x-world/x-vrml")
 894     (".xbm"   . "image/xbm")
 895     (".xpm"   . "image/xpm")
 896     (".xwd"   . "image/windowdump")
 897     (".zip"   . "application/zip")
 898     (".ai"    . "application/postscript")
 899     (".jpe"   . "image/jpeg")
 900     (".jpeg"  . "image/jpeg")
 901     (".org"   . "text/x-org"))
 902   "An alist of file extensions and corresponding MIME content-types.
 903 This exists for you to customize the information in Lisp.  It is
 904 merged with values from mailcap files by `mailcap-parse-mimetypes'.")
 905
 906 (defvar mailcap-mimetypes-parsed-p nil)
 907
 908 (defun mailcap-parse-mimetypes (&optional path force)
 909   "Parse out all the mimetypes specified in a Unix-style path string PATH.
 910 Components of PATH are separated by the `path-separator' character
 911 appropriate for this system.  If PATH is omitted, use the value of
 912 environment variable MIMETYPES if set; otherwise use a default path.
 913 If FORCE, re-parse even if already parsed."
 914   (interactive (list nil t))
 915   (when (or (not mailcap-mimetypes-parsed-p)
 916             force)
 917     (cond
 918      (path nil)
 919      ((getenv "MIMETYPES") (setq path (getenv "MIMETYPES")))
 920      ((memq system-type mailcap-poor-system-types)
 921       (setq path '("~/mime.typ" "~/etc/mime.typ")))
 922      (t (setq path
 923               ;; mime.types seems to be the normal name, definitely so
 924               ;; on current GNUish systems.  The search order follows
 925               ;; that for mailcap.
 926               '("~/.mime.types"
 927                 "/etc/mime.types"
 928                 "/usr/etc/mime.types"
 929                 "/usr/local/etc/mime.types"
 930                 "/usr/local/www/conf/mime.types"
 931                 "~/.mime-types"
 932                 "/etc/mime-types"
 933                 "/usr/etc/mime-types"
 934                 "/usr/local/etc/mime-types"
 935                 "/usr/local/www/conf/mime-types"))))
 936     (let ((fnames (reverse (if (stringp path)
 937                                (split-string path path-separator t)
 938                              path)))
 939           fname)
 940       (while fnames
 941         (setq fname (car fnames))
 942         (if (and (file-readable-p fname))
 943             (mailcap-parse-mimetype-file fname))
 944         (setq fnames (cdr fnames))))
 945     (setq mailcap-mimetypes-parsed-p t)))
 946
 947 (defun mailcap-parse-mimetype-file (fname)
 948   "Parse out a mime-types file FNAME."
 949   (let (type                            ; The MIME type for this line
 950         extns                           ; The extensions for this line
 951         save-pos                        ; Misc. saved buffer positions
 952         )
 953     (with-temp-buffer
 954       (insert-file-contents fname)
 955       (mailcap-replace-regexp "#.*" "")
 956       (mailcap-replace-regexp "\n+" "\n")
 957       (mailcap-replace-regexp "[ \t]+$" "")
 958       (goto-char (point-max))
 959       (skip-chars-backward " \t\n")
 960       (delete-region (point) (point-max))
 961       (goto-char (point-min))
 962       (while (not (eobp))
 963         (skip-chars-forward " \t\n")
 964         (setq save-pos (point))
 965         (skip-chars-forward "^ \t\n")
 966         (downcase-region save-pos (point))
 967         (setq type (buffer-substring save-pos (point)))
 968         (while (not (eolp))
 969           (skip-chars-forward " \t")
 970           (setq save-pos (point))
 971           (skip-chars-forward "^ \t\n")
 972           (setq extns (cons (buffer-substring save-pos (point)) extns)))
 973         (while extns
 974           (setq mailcap-mime-extensions
 975                 (cons
 976                  (cons (if (= (string-to-char (car extns)) ?.)
 977                            (car extns)
 978                          (concat "." (car extns))) type)
 979                  mailcap-mime-extensions)
 980                 extns (cdr extns)))))))
 981
 982 (defun mailcap-extension-to-mime (extn)
 983   "Return the MIME content type of the file extensions EXTN."
 984   (mailcap-parse-mimetypes)
 985   (if (and (stringp extn)
 986            (not (eq (string-to-char extn) ?.)))
 987       (setq extn (concat "." extn)))
 988   (cdr (assoc (downcase extn) mailcap-mime-extensions)))
 989
 990 ;; Unused?
 991 (defalias 'mailcap-command-p 'executable-find)
 992
 993 (defun mailcap-mime-types ()
 994   "Return a list of MIME media types."
 995   (mailcap-parse-mimetypes)
 996   (mailcap-delete-duplicates
 997    (nconc
 998     (mapcar 'cdr mailcap-mime-extensions)
 999     (apply
1000      'nconc
1001      (mapcar
1002       (lambda (l)
1003         (delq nil
1004               (mapcar
1005                (lambda (m)
1006                  (let ((type (cdr (assq 'type (cdr m)))))
1007                    (if (equal (cadr (split-string type "/"))
1008                               "*")
1009                        nil
1010                      type)))
1011                (cdr l))))
1012       mailcap-mime-data)))))
1013
1014 ;;;
1015 ;;; Useful supplementary functions
1016 ;;;
1017
1018 (defun mailcap-file-default-commands (files)
1019   "Return a list of default commands for FILES."
1020   (mailcap-parse-mailcaps)
1021   (mailcap-parse-mimetypes)
1022   (let* ((all-mime-type
1023           ;; All unique MIME types from file extensions
1024           (mailcap-delete-duplicates
1025            (mapcar (lambda (file)
1026                      (mailcap-extension-to-mime
1027                       (file-name-extension file t)))
1028                    files)))
1029          (all-mime-info
1030           ;; All MIME info lists
1031           (mailcap-delete-duplicates
1032            (mapcar (lambda (mime-type)
1033                      (mailcap-mime-info mime-type 'all))
1034                    all-mime-type)))
1035          (common-mime-info
1036           ;; Intersection of mime-infos from different mime-types;
1037           ;; or just the first MIME info for a single MIME type
1038           (if (cdr all-mime-info)
1039               (delq nil (mapcar (lambda (mi1)
1040                                   (unless (memq nil (mapcar
1041                                                      (lambda (mi2)
1042                                                        (member mi1 mi2))
1043                                                      (cdr all-mime-info)))
1044                                     mi1))
1045                                 (car all-mime-info)))
1046             (car all-mime-info)))
1047          (commands
1048           ;; Command strings from `viewer' field of the MIME info
1049           (mailcap-delete-duplicates
1050            (delq nil (mapcar (lambda (mime-info)
1051                                (let ((command (cdr (assoc 'viewer mime-info))))
1052                                  (if (stringp command)
1053                                      (mailcap-replace-in-string
1054                                       ;; Replace mailcap's `%s' placeholder
1055                                       ;; with dired's `?' placeholder
1056                                       (mailcap-replace-in-string
1057                                        ;; Remove the final filename placeholder
1058                                        command "[ \t\n]*\\('\\)?%s\\1?[ \t\n]*\\'" "" t)
1059                                       "%s" "?" t))))
1060                              common-mime-info)))))
1061     commands))
1062
1063 (provide 'mailcap)
1064
1065 ;;; mailcap.el ends here