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 the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This package can be used to arrange for automatic uncompress of
  27 ;; compressed files when they are visited.
  28 ;; All that's necessary is to load it.  This can conveniently be done from
  29 ;; your .emacs file.
  30
  31 ;; M-x auto-compression-mode is a more modern replacement for this package.
  32
  33 ;;; Code:
  34
  35 ;; When we are about to make a backup file,
  36 ;; uncompress the file we visited
  37 ;; so that making the backup can work properly.
  38 ;; This is used as a write-file-hook.
  39
  40 (defvar uncompress-program "gunzip"
  41   "Program to use for uncompression.")
  42
  43 (defun uncompress-backup-file ()
  44   (and buffer-file-name make-backup-files (not buffer-backed-up)
  45        (not (file-exists-p buffer-file-name))
  46        (call-process uncompress-program nil nil nil buffer-file-name))
  47   nil)
  48
  49 (or (assoc "\\.Z$" auto-mode-alist)
  50     (setq auto-mode-alist
  51           (cons '("\\.Z$" . uncompress-while-visiting) auto-mode-alist)))
  52 (or (assoc "\\.gz$" auto-mode-alist)
  53     (setq auto-mode-alist
  54           (cons '("\\.gz$" . uncompress-while-visiting) auto-mode-alist)))
  55 (or (assoc "\\.tgz$" auto-mode-alist)
  56     (setq auto-mode-alist
  57           (cons '("\\.tgz$" . uncompress-while-visiting) auto-mode-alist)))
  58
  59 (defun uncompress-while-visiting ()
  60   "Temporary \"major mode\" used for .Z and .gz files, to uncompress them.
  61 It then selects a major mode from the uncompressed file name and contents."
  62   (if (and (not (null buffer-file-name))
  63            (string-match "\\.Z$" buffer-file-name))
  64       (set-visited-file-name
  65        (substring buffer-file-name 0 (match-beginning 0)))
  66     (if (and (not (null buffer-file-name))
  67              (string-match "\\.gz$" buffer-file-name))
  68         (set-visited-file-name
  69          (substring buffer-file-name 0 (match-beginning 0)))
  70       (if (and (not (null buffer-file-name))
  71                (string-match "\\.tgz$" buffer-file-name))
  72           (set-visited-file-name
  73            (concat (substring buffer-file-name 0 (match-beginning 0)) ".tar")))))
  74   (message "Uncompressing...")
  75   (let ((buffer-read-only nil)
  76         (coding-system-for-write 'no-conversion)
  77         (coding-system-for-read
  78          (car (find-operation-coding-system
  79                'insert-file-contents
  80                buffer-file-name t))))
  81     (shell-command-on-region (point-min) (point-max) uncompress-program t))
  82   (goto-char (point-min))
  83   (message "Uncompressing...done")
  84   (set-buffer-modified-p nil)
  85   (make-local-variable 'write-file-hooks)
  86   (or (memq 'uncompress-backup-file write-file-hooks)
  87       (setq write-file-hooks (cons 'uncompress-backup-file write-file-hooks)))
  88   (normal-mode))
  89
  90 (or (memq 'find-compressed-version find-file-not-found-hooks)
  91     (setq find-file-not-found-hooks
  92           (cons 'find-compressed-version find-file-not-found-hooks)))
  93
  94 (defun find-compressed-version ()
  95   "Hook to read and uncompress the compressed version of a file."
  96   ;; Just pretend we had visited the compressed file,
  97   ;; and uncompress-while-visiting will do the rest.
  98   (let (name)
  99     (if (file-exists-p (setq name (concat buffer-file-name ".Z")))
 100         (setq buffer-file-name name)
 101       (if (file-exists-p (setq name (concat buffer-file-name ".gz")))
 102           (setq buffer-file-name name)))
 103     (if (eq name buffer-file-name)
 104         (progn
 105           (insert-file-contents buffer-file-name t)
 106           (goto-char (point-min))
 107           ;; No need for this, because error won't be set to t
 108           ;; if this function returns t.
 109           ;; (setq error nil)
 110           t))))
 111
 112 (provide 'uncompress)
 113
 114 ;;; uncompress.el ends here