lisp/uncompress.el

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