lisp/uncompress.el

   1 ;;; uncompress.el --- auto-decompression hook for visiting .Z files
   2
   3 ;; Copyright (C) 1992, 1994 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 ;;; Commentary:
  24
  25 ;; This package can be used to arrange for automatic uncompress of
  26 ;; files packed with the UNIX compress(1) utility when they are visited.
  27 ;; All that's necessary is to load it.  This can conveniently be done from
  28 ;; your .emacs file.
  29
  30 ;;; Code:
  31
  32 ;; When we are about to make a backup file,
  33 ;; uncompress the file we visited
  34 ;; so that making the backup can work properly.
  35 ;; This is used as a write-file-hook.
  36
  37 (defvar uncompress-program "gunzip"
  38   "Program to use for uncompression.")
  39
  40 (defun uncompress-backup-file ()
  41   (and buffer-file-name make-backup-files (not buffer-backed-up)
  42        (not (file-exists-p buffer-file-name))
  43        (call-process uncompress-program nil nil nil buffer-file-name))
  44   nil)
  45
  46 (or (assoc "\\.Z$" auto-mode-alist)
  47     (setq auto-mode-alist
  48           (cons '("\\.Z$" . uncompress-while-visiting) auto-mode-alist)))
  49 (or (assoc "\\.gz$" auto-mode-alist)
  50     (setq auto-mode-alist
  51           (cons '("\\.gz$" . uncompress-while-visiting) auto-mode-alist)))
  52
  53 (defun uncompress-while-visiting ()
  54   "Temporary \"major mode\" used for .Z and .gz files, to uncompress them.
  55 It then selects a major mode from the uncompressed file name and contents."
  56   (if (and (not (null buffer-file-name))
  57            (string-match "\\.Z$" buffer-file-name))
  58       (set-visited-file-name
  59        (substring buffer-file-name 0 (match-beginning 0)))
  60     (if (and (not (null buffer-file-name))
  61              (string-match "\\.gz$" buffer-file-name))
  62         (set-visited-file-name
  63          (substring buffer-file-name 0 (match-beginning 0)))))
  64   (message "Uncompressing...")
  65   (let ((buffer-read-only nil))
  66     (shell-command-on-region (point-min) (point-max) uncompress-program t))
  67   (message "Uncompressing...done")
  68   (set-buffer-modified-p nil)
  69   (make-local-variable 'write-file-hooks)
  70   (or (memq 'uncompress-backup-file write-file-hooks)
  71       (setq write-file-hooks (cons 'uncompress-backup-file write-file-hooks)))
  72   (normal-mode))
  73
  74 (or (memq 'find-compressed-version find-file-not-found-hooks)
  75     (setq find-file-not-found-hooks
  76           (cons 'find-compressed-version find-file-not-found-hooks)))
  77
  78 (defun find-compressed-version ()
  79   "Hook to read and uncompress the compressed version of a file."
  80   ;; Just pretend we had visited the compressed file,
  81   ;; and uncompress-while-visiting will do the rest.
  82   (let (name)
  83     (if (file-exists-p (setq name (concat buffer-file-name ".Z")))
  84         (setq buffer-file-name name)
  85       (if (file-exists-p (setq name (concat buffer-file-name ".gz")))
  86           (setq buffer-file-name name)))
  87     (if (eq name buffer-file-name)
  88         (progn
  89           (insert-file-contents buffer-file-name t)
  90           (goto-char (point-min))
  91           (setq error nil)
  92           t))))
  93
  94 (provide 'uncompress)
  95
  96 ;;; uncompress.el ends here