lisp/uncompress.el

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