lisp/jka-compr.el

   1 ;;; jka-compr.el --- reading/writing/loading compressed files
   2
   3 ;; Copyright (C) 1993-1995, 1997, 1999-2013 Free Software Foundation,
   4 ;; Inc.
   5
   6 ;; Author: jka@ece.cmu.edu (Jay K. Adams)
   7 ;; Maintainer: FSF
   8 ;; Keywords: data
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This package implements low-level support for reading, writing,
  28 ;; and loading compressed files.  It hooks into the low-level file
  29 ;; I/O functions (including write-region and insert-file-contents) so
  30 ;; that they automatically compress or uncompress a file if the file
  31 ;; appears to need it (based on the extension of the file name).
  32 ;; Packages like Rmail, VM, GNUS, and Info should be able to work
  33 ;; with compressed files without modification.
  34
  35
  36 ;; INSTRUCTIONS:
  37 ;;
  38 ;; To use jka-compr, invoke the command `auto-compression-mode' (which
  39 ;; see), or customize the variable of the same name.  Its operation
  40 ;; should be transparent to the user (except for messages appearing when
  41 ;; a file is being compressed or uncompressed).
  42 ;;
  43 ;; The variable, jka-compr-compression-info-list can be used to
  44 ;; customize jka-compr to work with other compression programs.
  45 ;; The default value of this variable allows jka-compr to work with
  46 ;; Unix compress and gzip.
  47 ;;
  48 ;; If you don't want messages about compressing and decompressing
  49 ;; to show up in the echo area, you can set the compress-msg and
  50 ;; decompress-msg fields of the jka-compr-compression-info-list to
  51 ;; nil.
  52
  53
  54 ;; APPLICATION NOTES:
  55 ;;
  56 ;; crypt++
  57 ;;   jka-compr can coexist with crypt++ if you take all the decompression
  58 ;;   entries out of the crypt-encoding-list.  Clearly problems will arise if
  59 ;;   you have two programs trying to compress/decompress files.  jka-compr
  60 ;;   will not "work with" crypt++ in the following sense: you won't be able to
  61 ;;   decode encrypted compressed files--that is, files that have been
  62 ;;   compressed then encrypted (in that order).  Theoretically, crypt++ and
  63 ;;   jka-compr could properly handle a file that has been encrypted then
  64 ;;   compressed, but there is little point in trying to compress an encrypted
  65 ;;   file.
  66 ;;
  67
  68
  69 ;; ACKNOWLEDGMENTS
  70 ;;
  71 ;; jka-compr is a V19 adaptation of jka-compr for V18 of Emacs.  Many people
  72 ;; have made helpful suggestions, reported bugs, and even fixed bugs in
  73 ;; jka-compr.  I recall the following people as being particularly helpful.
  74 ;;
  75 ;;   Jean-loup Gailly
  76 ;;   David Hughes
  77 ;;   Richard Pieri
  78 ;;   Daniel Quinlan
  79 ;;   Chris P. Ross
  80 ;;   Rick Sladkey
  81 ;;
  82 ;; Andy Norman's ange-ftp was the inspiration for the original jka-compr for
  83 ;; Version 18 of Emacs.
  84 ;;
  85 ;; After I had made progress on the original jka-compr for V18, I learned of a
  86 ;; package written by Kazushi Jam Marukawa, called jam-zcat, that did exactly
  87 ;; what I was trying to do.  I looked over the jam-zcat source code and
  88 ;; probably got some ideas from it.
  89 ;;
  90
  91 ;;; Code:
  92
  93 (require 'jka-cmpr-hook)
  94
  95 (defcustom jka-compr-shell "sh"
  96   "Shell to be used for calling compression programs.
  97 NOTE: Not used in MS-DOS and Windows systems."
  98   :type 'string
  99   :group 'jka-compr)
 100
 101 (defvar jka-compr-use-shell
 102   (not (memq system-type '(ms-dos windows-nt))))
 103
 104 (defvar jka-compr-really-do-compress nil
 105   "Non-nil in a buffer whose visited file was uncompressed on visiting it.
 106 This means compress the data on writing the file, even if the
 107 data appears to be compressed already.")
 108 (make-variable-buffer-local 'jka-compr-really-do-compress)
 109 (put 'jka-compr-really-do-compress 'permanent-local t)
 110 \f
 111
 112 (put 'compression-error 'error-conditions '(compression-error file-error error))
 113
 114
 115 (defvar jka-compr-acceptable-retval-list '(0 2 141))
 116
 117
 118 (defun jka-compr-error (prog args infile message &optional errfile)
 119
 120   (let ((errbuf (get-buffer-create " *jka-compr-error*")))
 121     (with-current-buffer errbuf
 122       (widen) (erase-buffer)
 123       (insert (format "Error while executing \"%s %s < %s\"\n\n"
 124                       prog
 125                       (mapconcat 'identity args " ")
 126                       infile))
 127
 128       (and errfile
 129            (insert-file-contents errfile)))
 130      (display-buffer errbuf))
 131
 132   (signal 'compression-error
 133           (list "Opening input file" (format "error %s" message) infile)))
 134
 135
 136 (defcustom jka-compr-dd-program "/bin/dd"
 137   "How to invoke `dd'."
 138   :type 'string
 139   :group 'jka-compr)
 140
 141
 142 (defvar jka-compr-dd-blocksize 256)
 143
 144
 145 (defun jka-compr-partial-uncompress (prog message args infile beg len)
 146   "Call program PROG with ARGS args taking input from INFILE.
 147 Fourth and fifth args, BEG and LEN, specify which part of the output
 148 to keep: LEN chars starting BEG chars from the beginning."
 149   (let ((start (point))
 150         (prefix beg))
 151     (if (and jka-compr-use-shell jka-compr-dd-program)
 152         ;; Put the uncompression output through dd
 153         ;; to discard the part we don't want.
 154         (let ((skip (/ beg jka-compr-dd-blocksize))
 155               (err-file (jka-compr-make-temp-name))
 156               ;; call-process barfs if default-directory is inaccessible.
 157               (default-directory
 158                 (if (and default-directory
 159                          (file-accessible-directory-p default-directory))
 160                     default-directory
 161                   (file-name-directory infile)))
 162               count)
 163           ;; Update PREFIX based on the text that we won't read in.
 164           (setq prefix (- beg (* skip jka-compr-dd-blocksize))
 165                 count (and len (1+ (/ (+ len prefix) jka-compr-dd-blocksize))))
 166           (unwind-protect
 167               (or (memq (call-process
 168                          jka-compr-shell infile t nil "-c"
 169                          ;; Windows shells need the program file name
 170                          ;; after the pipe symbol be quoted if they use
 171                          ;; forward slashes as directory separators.
 172                          (format
 173                           "%s %s 2> %s | \"%s\" bs=%d skip=%d %s 2> %s"
 174                           prog
 175                           (mapconcat 'identity args " ")
 176                           err-file
 177                           jka-compr-dd-program
 178                           jka-compr-dd-blocksize
 179                           skip
 180                           ;; dd seems to be unreliable about
 181                           ;; providing the last block.  So, always
 182                           ;; read one more than you think you need.
 183                           (if count (format "count=%d" (1+ count)) "")
 184                           null-device))
 185                         jka-compr-acceptable-retval-list)
 186                   (jka-compr-error prog args infile message err-file))
 187             (delete-file err-file)))
 188
 189       ;; Run the uncompression program directly.
 190       ;; We get the whole file and must delete what we don't want.
 191       (jka-compr-call-process prog message infile t nil args))
 192
 193     ;; Delete the stuff after what we want, if there is any.
 194     (and
 195      len
 196      (< (+ start prefix len) (point))
 197      (delete-region (+ start prefix len) (point)))
 198
 199     ;; Delete the stuff before what we want.
 200     (delete-region start (+ start prefix))))
 201
 202
 203 (defun jka-compr-call-process (prog message infile output temp args)
 204   ;; call-process barfs if default-directory is inaccessible.
 205   (let ((default-directory
 206           (if (and default-directory
 207                    (not (file-remote-p default-directory))
 208                    (file-accessible-directory-p default-directory))
 209               default-directory
 210             (file-name-directory infile))))
 211     (if jka-compr-use-shell
 212         (let ((err-file (jka-compr-make-temp-name))
 213               (coding-system-for-read (or coding-system-for-read 'undecided))
 214               (coding-system-for-write 'no-conversion))
 215           (unwind-protect
 216               (or (memq
 217                    (call-process jka-compr-shell infile
 218                                  (if (stringp output) nil output)
 219                                  nil
 220                                  "-c"
 221                                  (format "%s %s 2> %s %s"
 222                                          prog
 223                                          (mapconcat 'identity args " ")
 224                                          err-file
 225                                          (if (stringp output)
 226                                              (concat "> " output)
 227                                            "")))
 228                    jka-compr-acceptable-retval-list)
 229                   (jka-compr-error prog args infile message err-file))
 230             (delete-file err-file)))
 231       (or (eq 0
 232               (apply 'call-process
 233                      prog infile (if (stringp output) temp output)
 234                      nil args))
 235           (jka-compr-error prog args infile message))
 236       (and (stringp output)
 237            (with-current-buffer temp
 238              (write-region (point-min) (point-max) output)
 239              (erase-buffer))))))
 240
 241
 242 ;; Support for temp files.  Much of this was inspired if not lifted
 243 ;; from ange-ftp.
 244
 245 (defcustom jka-compr-temp-name-template
 246   (expand-file-name "jka-com" temporary-file-directory)
 247   "Prefix added to all temp files created by jka-compr.
 248 There should be no more than seven characters after the final `/'."
 249   :type 'string
 250   :group 'jka-compr)
 251
 252 (defun jka-compr-make-temp-name (&optional _local-copy)
 253   "This routine will return the name of a new file."
 254   (make-temp-file jka-compr-temp-name-template))
 255
 256 (defun jka-compr-write-region (start end file &optional append visit)
 257   (let* ((filename (expand-file-name file))
 258          (visit-file (if (stringp visit) (expand-file-name visit) filename))
 259          (info (jka-compr-get-compression-info visit-file))
 260          (magic (and info (jka-compr-info-file-magic-bytes info))))
 261
 262     ;; If we uncompressed this file when visiting it,
 263     ;; then recompress it when writing it
 264     ;; even if the contents look compressed already.
 265     (if (and jka-compr-really-do-compress
 266              (or (null start)
 267                  (= (- end start) (buffer-size))))
 268         (setq magic nil))
 269
 270     (if (and info
 271              ;; If the contents to be written out
 272              ;; are properly compressed already,
 273              ;; don't try to compress them over again.
 274              (not (and magic
 275                        (equal (if (stringp start)
 276                                   (substring start 0 (min (length start)
 277                                                           (length magic)))
 278                                 (let* ((from (or start (point-min)))
 279                                        (to (min (or end (point-max))
 280                                                 (+ from (length magic)))))
 281                                   (buffer-substring from to)))
 282                               magic))))
 283         (let ((can-append (jka-compr-info-can-append info))
 284               (compress-program (jka-compr-info-compress-program info))
 285               (compress-message (jka-compr-info-compress-message info))
 286               (compress-args (jka-compr-info-compress-args info))
 287               (base-name (file-name-nondirectory visit-file))
 288               temp-file temp-buffer
 289               ;; we need to leave `last-coding-system-used' set to its
 290               ;; value after calling write-region the first time, so
 291               ;; that `basic-save-buffer' sees the right value.
 292               (coding-system-used last-coding-system-used))
 293
 294           (or compress-program
 295               (error "No compression program defined"))
 296
 297           (setq temp-buffer (get-buffer-create " *jka-compr-wr-temp*"))
 298           (with-current-buffer temp-buffer
 299             (widen) (erase-buffer))
 300
 301           (if (and append
 302                    (not can-append)
 303                    (file-exists-p filename))
 304
 305               (let* ((local-copy (file-local-copy filename))
 306                      (local-file (or local-copy filename)))
 307
 308                 (setq temp-file local-file))
 309
 310             (setq temp-file (jka-compr-make-temp-name)))
 311
 312           (and
 313            compress-message
 314            jka-compr-verbose
 315            (message "%s %s..." compress-message base-name))
 316
 317           (jka-compr-run-real-handler 'write-region
 318                                       (list start end temp-file t 'dont))
 319           ;; save value used by the real write-region
 320           (setq coding-system-used last-coding-system-used)
 321
 322           ;; Here we must read the output of compress program as is
 323           ;; without any code conversion.
 324           (let ((coding-system-for-read 'no-conversion))
 325             (jka-compr-call-process compress-program
 326                                     (concat compress-message
 327                                             " " base-name)
 328                                     temp-file
 329                                     temp-buffer
 330                                     nil
 331                                     compress-args))
 332
 333           (with-current-buffer temp-buffer
 334             (let ((coding-system-for-write 'no-conversion))
 335               (jka-compr-run-real-handler 'write-region
 336                                           (list (point-min) (point-max)
 337                                                 filename
 338                                                 (and append can-append) 'dont))
 339               (erase-buffer)) )
 340
 341           (delete-file temp-file)
 342
 343           (and
 344            compress-message
 345            jka-compr-verbose
 346            (message "%s %s...done" compress-message base-name))
 347
 348           (cond
 349            ((eq visit t)
 350             (setq buffer-file-name filename)
 351             (setq jka-compr-really-do-compress t)
 352             (set-visited-file-modtime))
 353            ((stringp visit)
 354             (setq buffer-file-name visit)
 355             (let ((buffer-file-name filename))
 356               (set-visited-file-modtime))))
 357
 358           (and (or (eq visit t)
 359                    (eq visit nil)
 360                    (stringp visit))
 361                (message "Wrote %s" visit-file))
 362
 363           ;; ensure `last-coding-system-used' has an appropriate value
 364           (setq last-coding-system-used coding-system-used)
 365
 366           nil)
 367
 368       (jka-compr-run-real-handler 'write-region
 369                                   (list start end filename append visit)))))
 370
 371
 372 (defun jka-compr-insert-file-contents (file &optional visit beg end replace)
 373   (barf-if-buffer-read-only)
 374
 375   (and (or beg end)
 376        visit
 377        (error "Attempt to visit less than an entire file"))
 378
 379   (let* ((filename (expand-file-name file))
 380          (info (jka-compr-get-compression-info filename)))
 381
 382     (if (not info)
 383
 384         (jka-compr-run-real-handler 'insert-file-contents
 385                                     (list file visit beg end replace))
 386
 387       (let ((uncompress-message (jka-compr-info-uncompress-message info))
 388             (uncompress-program (jka-compr-info-uncompress-program info))
 389             (uncompress-args (jka-compr-info-uncompress-args info))
 390             (base-name (file-name-nondirectory filename))
 391             (notfound nil)
 392             (local-copy
 393              (jka-compr-run-real-handler 'file-local-copy (list filename)))
 394             local-file
 395             size start)
 396
 397         (setq local-file (or local-copy filename))
 398
 399         (and
 400          visit
 401          (setq buffer-file-name filename))
 402
 403         (unwind-protect               ; to make sure local-copy gets deleted
 404
 405             (progn
 406
 407               (and
 408                uncompress-message
 409                jka-compr-verbose
 410                (message "%s %s..." uncompress-message base-name))
 411
 412               (condition-case error-code
 413
 414                   (let ((coding-system-for-read 'no-conversion))
 415                     (if replace
 416                         (goto-char (point-min)))
 417                     (setq start (point))
 418                     (if (or beg end)
 419                         (jka-compr-partial-uncompress uncompress-program
 420                                                       (concat uncompress-message
 421                                                               " " base-name)
 422                                                       uncompress-args
 423                                                       local-file
 424                                                       (or beg 0)
 425                                                       (if (and beg end)
 426                                                           (- end beg)
 427                                                         end))
 428                       ;; If visiting, bind off buffer-file-name so that
 429                       ;; file-locking will not ask whether we should
 430                       ;; really edit the buffer.
 431                       (let ((buffer-file-name
 432                              (if visit nil buffer-file-name)))
 433                         (jka-compr-call-process uncompress-program
 434                                                 (concat uncompress-message
 435                                                         " " base-name)
 436                                                 local-file
 437                                                 t
 438                                                 nil
 439                                                 uncompress-args)))
 440                     (setq size (- (point) start))
 441                     (if replace
 442                         (delete-region (point) (point-max)))
 443                     (goto-char start))
 444                 (error
 445                  ;; If the file we wanted to uncompress does not exist,
 446                  ;; handle that according to VISIT as `insert-file-contents'
 447                  ;; would, maybe signaling the same error it normally would.
 448                  (if (and (eq (car error-code) 'file-error)
 449                           (eq (nth 3 error-code) local-file))
 450                      (if visit
 451                          (setq notfound error-code)
 452                        (signal 'file-error
 453                                (cons "Opening input file"
 454                                      (nthcdr 2 error-code))))
 455                    ;; If the uncompression program can't be found,
 456                    ;; signal that as a non-file error
 457                    ;; so that find-file-noselect-1 won't handle it.
 458                    (if (and (eq (car error-code) 'file-error)
 459                             (equal (cadr error-code) "Searching for program"))
 460                        (error "Uncompression program `%s' not found"
 461                               (nth 3 error-code)))
 462                    (signal (car error-code) (cdr error-code))))))
 463
 464           (and
 465            local-copy
 466            (file-exists-p local-copy)
 467            (delete-file local-copy)))
 468
 469         (unless notfound
 470           (decode-coding-inserted-region
 471            (point) (+ (point) size)
 472            (jka-compr-byte-compiler-base-file-name file)
 473            visit beg end replace))
 474
 475         (and
 476          visit
 477          (progn
 478            (unlock-buffer)
 479            (setq buffer-file-name filename)
 480            (setq jka-compr-really-do-compress t)
 481            (set-visited-file-modtime)))
 482
 483         (and
 484          uncompress-message
 485          jka-compr-verbose
 486          (message "%s %s...done" uncompress-message base-name))
 487
 488         (and
 489          visit
 490          notfound
 491          (signal 'file-error
 492                  (cons "Opening input file" (nth 2 notfound))))
 493
 494         ;; This is done in insert-file-contents after we return.
 495         ;; That is a little weird, but better to go along with it now
 496         ;; than to change it now.
 497
 498         ;; ;; Run the functions that insert-file-contents would.
 499         ;; (let ((p after-insert-file-functions)
 500         ;;       (insval size))
 501         ;;   (while p
 502         ;;     (setq insval (funcall (car p) size))
 503         ;;     (if insval
 504         ;;         (progn
 505         ;;           (or (integerp insval)
 506         ;;              (signal 'wrong-type-argument
 507         ;;                      (list 'integerp insval)))
 508         ;;           (setq size insval)))
 509         ;;     (setq p (cdr p))))
 510
 511         (or (jka-compr-info-compress-program info)
 512             (message "You can't save this buffer because compression program is not defined"))
 513
 514         (list filename size)))))
 515
 516
 517 (defun jka-compr-file-local-copy (file)
 518   (let* ((filename (expand-file-name file))
 519          (info (jka-compr-get-compression-info filename)))
 520
 521     (if info
 522
 523         (let ((uncompress-message (jka-compr-info-uncompress-message info))
 524               (uncompress-program (jka-compr-info-uncompress-program info))
 525               (uncompress-args (jka-compr-info-uncompress-args info))
 526               (base-name (file-name-nondirectory filename))
 527               (local-copy
 528                (jka-compr-run-real-handler 'file-local-copy (list filename)))
 529               (temp-file (jka-compr-make-temp-name t))
 530               (temp-buffer (get-buffer-create " *jka-compr-flc-temp*"))
 531               local-file)
 532
 533           (setq local-file (or local-copy filename))
 534
 535           (unwind-protect
 536
 537               (with-current-buffer temp-buffer
 538
 539                 (and
 540                  uncompress-message
 541                  jka-compr-verbose
 542                  (message "%s %s..." uncompress-message base-name))
 543
 544                 ;; Here we must read the output of uncompress program
 545                 ;; and write it to TEMP-FILE without any code
 546                 ;; conversion.  An appropriate code conversion (if
 547                 ;; necessary) is done by the later I/O operation
 548                 ;; (e.g. load).
 549                 (let ((coding-system-for-read 'no-conversion)
 550                       (coding-system-for-write 'no-conversion))
 551
 552                   (jka-compr-call-process uncompress-program
 553                                           (concat uncompress-message
 554                                                   " " base-name)
 555                                           local-file
 556                                           t
 557                                           nil
 558                                           uncompress-args)
 559
 560                   (and
 561                    uncompress-message
 562                    jka-compr-verbose
 563                    (message "%s %s...done" uncompress-message base-name))
 564
 565                   (write-region
 566                    (point-min) (point-max) temp-file nil 'dont)))
 567
 568             (and
 569              local-copy
 570              (file-exists-p local-copy)
 571              (delete-file local-copy))
 572
 573             (kill-buffer temp-buffer))
 574
 575           temp-file)
 576
 577       (jka-compr-run-real-handler 'file-local-copy (list filename)))))
 578
 579
 580 ;; Support for loading compressed files.
 581 (defun jka-compr-load (file &optional noerror nomessage _nosuffix)
 582   "Documented as original."
 583
 584   (let* ((local-copy (jka-compr-file-local-copy file))
 585          (load-file (or local-copy file)))
 586
 587     (unwind-protect
 588
 589         (let (inhibit-file-name-operation
 590               inhibit-file-name-handlers)
 591           (or nomessage
 592               (message "Loading %s..." file))
 593
 594           (let ((load-force-doc-strings t))
 595             (load load-file noerror t t))
 596           (or nomessage
 597               (message "Loading %s...done." file))
 598           ;; Fix up the load history to point at the right library.
 599           (let ((l (or (assoc load-file load-history)
 600                        ;; On MS-Windows, if load-file is in
 601                        ;; temporary-file-directory, it will look like
 602                        ;; "c:/DOCUME~1/USER/LOCALS~1/foo", whereas
 603                        ;; readevalloop will record its truename in
 604                        ;; load-history.  Therefore try truename if the
 605                        ;; original name is not in load-history.
 606                        (assoc (file-truename load-file) load-history))))
 607             ;; Remove .gz and .elc?.
 608             (while (file-name-extension file)
 609               (setq file (file-name-sans-extension file)))
 610             (setcar l file)))
 611
 612       (delete-file local-copy))
 613
 614     t))
 615
 616 (defun jka-compr-byte-compiler-base-file-name (file)
 617   (let ((info (jka-compr-get-compression-info file)))
 618     (if (and info (jka-compr-info-strip-extension info))
 619         (save-match-data
 620           (substring file 0 (string-match (jka-compr-info-regexp info) file)))
 621       file)))
 622 \f
 623 (put 'write-region 'jka-compr 'jka-compr-write-region)
 624 (put 'insert-file-contents 'jka-compr 'jka-compr-insert-file-contents)
 625 (put 'file-local-copy 'jka-compr 'jka-compr-file-local-copy)
 626 (put 'load 'jka-compr 'jka-compr-load)
 627 (put 'byte-compiler-base-file-name 'jka-compr
 628      'jka-compr-byte-compiler-base-file-name)
 629
 630 ;;;###autoload
 631 (defvar jka-compr-inhibit nil
 632   "Non-nil means inhibit automatic uncompression temporarily.
 633 Lisp programs can bind this to t to do that.
 634 It is not recommended to set this variable permanently to anything but nil.")
 635
 636 ;;;###autoload
 637 (defun jka-compr-handler (operation &rest args)
 638   (save-match-data
 639     (let ((jka-op (get operation 'jka-compr)))
 640       (if (and jka-op (not jka-compr-inhibit))
 641           (apply jka-op args)
 642         (jka-compr-run-real-handler operation args)))))
 643
 644 ;; If we are given an operation that we don't handle,
 645 ;; call the Emacs primitive for that operation,
 646 ;; and manipulate the inhibit variables
 647 ;; to prevent the primitive from calling our handler again.
 648 (defun jka-compr-run-real-handler (operation args)
 649   (let ((inhibit-file-name-handlers
 650          (cons 'jka-compr-handler
 651                (and (eq inhibit-file-name-operation operation)
 652                     inhibit-file-name-handlers)))
 653         (inhibit-file-name-operation operation))
 654     (apply operation args)))
 655
 656 ;;;###autoload
 657 (defun jka-compr-uninstall ()
 658   "Uninstall jka-compr.
 659 This removes the entries in `file-name-handler-alist' and `auto-mode-alist'
 660 and `inhibit-local-variables-suffixes' that were added
 661 by `jka-compr-installed'."
 662   ;; Delete from inhibit-local-variables-suffixes what jka-compr-install added.
 663   (mapc
 664      (function (lambda (x)
 665                  (and (jka-compr-info-strip-extension x)
 666                       (setq inhibit-local-variables-suffixes
 667                             (delete (jka-compr-info-regexp x)
 668                                     inhibit-local-variables-suffixes)))))
 669      jka-compr-compression-info-list--internal)
 670
 671   (let* ((fnha (cons nil file-name-handler-alist))
 672          (last fnha))
 673
 674     (while (cdr last)
 675       (if (eq (cdr (car (cdr last))) 'jka-compr-handler)
 676           (setcdr last (cdr (cdr last)))
 677         (setq last (cdr last))))
 678
 679     (setq file-name-handler-alist (cdr fnha)))
 680
 681   (let* ((ama (cons nil auto-mode-alist))
 682          (last ama)
 683          entry)
 684
 685     (while (cdr last)
 686       (setq entry (car (cdr last)))
 687       (if (or (member entry jka-compr-mode-alist-additions--internal)
 688               (and (consp (cdr entry))
 689                    (eq (nth 2 entry) 'jka-compr)))
 690           (setcdr last (cdr (cdr last)))
 691         (setq last (cdr last))))
 692
 693     (setq auto-mode-alist (cdr ama)))
 694
 695   (while jka-compr-added-to-file-coding-system-alist
 696     (setq file-coding-system-alist
 697           (delq (car (member (pop jka-compr-added-to-file-coding-system-alist)
 698                              file-coding-system-alist))
 699                 file-coding-system-alist)))
 700
 701   ;; Remove the suffixes that were added by jka-compr.
 702   (dolist (suff jka-compr-load-suffixes--internal)
 703     (setq load-file-rep-suffixes (delete suff load-file-rep-suffixes)))
 704
 705   (setq jka-compr-compression-info-list--internal nil
 706         jka-compr-mode-alist-additions--internal nil
 707         jka-compr-load-suffixes--internal nil))
 708
 709 (provide 'jka-compr)
 710
 711 ;;; jka-compr.el ends here