lisp/uncompress.el

   1 ;;; uncompress.el --- auto-decompression hook for visiting .Z files
   2
   3 ;; Maintainer: FSF
   4 ;; Last-Modified: 30 May 1988
   5
   6 ;; Copyright (C) 1992 Free Software Foundation, Inc.
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Code:
  25
  26 ;; When we are about to make a backup file,
  27 ;; uncompress the file we visited
  28 ;; so that making the backup can work properly.
  29 ;; This is used as a write-file-hook.
  30
  31 (defun uncompress-backup-file ()
  32   (and buffer-file-name make-backup-files (not buffer-backed-up)
  33        (not (file-exists-p buffer-file-name))
  34        (call-process "uncompress" nil nil nil buffer-file-name))
  35   nil)
  36
  37 (or (assoc "\\.Z$" auto-mode-alist)
  38     (setq auto-mode-alist
  39           (cons '("\\.Z$" . uncompress-while-visiting) auto-mode-alist)))
  40
  41 (defun uncompress-while-visiting ()
  42   "Temporary \"major mode\" used for .Z files, to uncompress the contents.
  43 It then selects a major mode from the uncompressed file name and contents."
  44   (if (and (not (null buffer-file-name))
  45            (string-match "\\.Z$" buffer-file-name))
  46       (set-visited-file-name
  47        (substring buffer-file-name 0 (match-beginning 0))))
  48   (message "Uncompressing...")
  49   (let ((buffer-read-only nil))
  50     (shell-command-on-region (point-min) (point-max) "uncompress" t))
  51   (message "Uncompressing...done")
  52   (set-buffer-modified-p nil)
  53   (make-local-variable 'write-file-hooks)
  54   (or (memq 'uncompress-backup-file write-file-hooks)
  55       (setq write-file-hooks (cons 'uncompress-backup-file write-file-hooks)))
  56   (normal-mode))
  57
  58 (or (memq 'find-compressed-version find-file-not-found-hooks)
  59     (setq find-file-not-found-hooks
  60           (cons 'find-compressed-version find-file-not-found-hooks)))
  61
  62 (defun find-compressed-version ()
  63   "Hook to read and uncompress the compressed version of a file."
  64   ;; Just pretend we had visited the compressed file,
  65   ;; and uncompress-while-visiting will do the rest.
  66   (if (file-exists-p (concat buffer-file-name ".Z"))
  67       (progn
  68         (setq buffer-file-name (concat buffer-file-name ".Z"))
  69         (insert-file-contents buffer-file-name t)
  70         (goto-char (point-min))
  71         (setq error nil)
  72         t)))
  73
  74 ;;; uncompress.el ends here