;;; dos-win32.el --- Functions shared among MS-DOS and Win32 (NT/95) platforms

;; Copyright (C) 1996 Free Software Foundation, Inc.

;; Maintainer: Geoff Voelker (voelker@cs.washington.edu)
;; Keywords: internal

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Parts of this code are duplicated functions taken from dos-fns.el
;; and winnt.el.

;;; Code:

;;; Add %t: into the mode line format just after the open-paren.
(let ((tail (member "   %[(" mode-line-format)))
  (setcdr tail (cons (purecopy "%t:")
		     (cdr tail))))

;; Use ";" instead of ":" as a path separator (from files.el).
(setq path-separator ";")

;; Set the null device (for compile.el).
(setq grep-null-device "NUL")

;; Set the grep regexp to match entries with drive letters.
(setq grep-regexp-alist
  '(("^\\(\\([a-zA-Z]:\\)?[^:( \t\n]+\\)[:( \t]+\\([0-9]+\\)[:) \t]" 1 3)))

;; For distinguishing file types based upon suffixes.
(defvar file-name-buffer-file-type-alist
  '(
    ("[:/].*config.sys$" . nil)		; config.sys text
    ("\\.elc$" . t)			; emacs stuff
    ("\\.\\(obj\\|exe\\|com\\|lib\\|sys\\|chk\\|out\\|bin\\|ico\\|pif\\)$" . t)
					; MS-Dos stuff
    ("\\.\\(arc\\|zip\\|pak\\|lzh\\|zoo\\)$" . t)
					; Packers
    ("\\.\\(a\\|o\\|tar\\|z\\|gz\\|taz\\)$" . t)
					; Unix stuff
    ("\\.tp[ulpw]$" . t)
					; Borland Pascal stuff
    ("[:/]tags$" . t)
					; Emacs TAGS file
    )
  "*Alist for distinguishing text files from binary files.
Each element has the form (REGEXP . TYPE), where REGEXP is matched
against the file name, and TYPE is nil for text, t for binary.")

(defun find-buffer-file-type (filename)
  ;; First check if file is on an untranslated filesystem, then on the alist.
  (if (untranslated-file-p filename)
      t ; for binary
    (let ((alist file-name-buffer-file-type-alist)
	  (found nil)
	  (code nil))
      (let ((case-fold-search t))
	(setq filename (file-name-sans-versions filename))
	(while (and (not found) alist)
	  (if (string-match (car (car alist)) filename)
	      (setq code (cdr (car alist))
		    found t))
	  (setq alist (cdr alist))))
      (if found
	  (cond ((memq code '(nil t)) code)
		((and (symbolp code) (fboundp code))
		 (funcall code filename)))
	default-buffer-file-type))))

(defun find-file-binary (filename)
  "Visit file FILENAME and treat it as binary."
  (interactive "FFind file binary: ")
  (let ((file-name-buffer-file-type-alist '(("" . t))))
    (find-file filename)))

(defun find-file-text (filename)
  "Visit file FILENAME and treat it as a text file."
  (interactive "FFind file text: ")
  (let ((file-name-buffer-file-type-alist '(("" . nil))))
    (find-file filename)))

(defun find-file-not-found-set-buffer-file-type ()
  (save-excursion
    (set-buffer (current-buffer))
    (setq buffer-file-type (find-buffer-file-type (buffer-file-name))))
  nil)

;;; To set the default file type on new files.
(add-hook 'find-file-not-found-hooks 'find-file-not-found-set-buffer-file-type)


;;; To accomodate filesystems that do not require CR/LF translation.
(defvar untranslated-filesystem-list nil
  "List of filesystems that require no CR/LF translation during file I/O.
Each element in the list is a string naming the directory prefix
corresponding to the filesystem.")

(defun untranslated-canonical-name (filename)
  "Return FILENAME in a canonicalized form.
This is for use with the functions dealing with untranslated filesystems."
  (if (memq system-type '(ms-dos windows-nt))
      ;; The canonical form for DOS/NT/Win95 is with A-Z downcased and all
      ;; directory separators changed to directory-sep-char.
      (let ((name nil))
	(setq name (mapconcat
		    '(lambda (char)
		       (if (and (<= ?A char) (<= char ?Z))
			   (char-to-string (+ (- char ?A) ?a))
			 (char-to-string char)))
		    filename nil))
	;; Use expand-file-name to canonicalize directory separators, except
	;; with bare drive letters (which would have the cwd appended).
	(if (string-match "^.:$" name)
	    name
	  (expand-file-name name)))
    filename))

(defun untranslated-file-p (filename)
  "Test whether CR/LF translation should be disabled for FILENAME.
Return t if FILENAME is on a filesystem that does not require
CR/LF translation, and nil otherwise."
  (let ((fs (untranslated-canonical-name filename))
	(ufs-list untranslated-filesystem-list)
	(found nil))
    (while (and (not found) ufs-list)
      (if (string-match (concat "^" (regexp-quote (car ufs-list))) fs)
	  (setq found t)
	(setq ufs-list (cdr ufs-list))))
    found))

(defun add-untranslated-filesystem (filesystem)
  "Record that FILESYSTEM does not require CR/LF translation.
FILESYSTEM is a string containing the directory prefix corresponding to
the filesystem.  For example, for a Unix filesystem mounted on drive Z:,
FILESYSTEM could be \"Z:\"."
  (let ((fs (untranslated-canonical-name filesystem)))
    (if (member fs untranslated-filesystem-list)
	untranslated-filesystem-list
      (setq untranslated-filesystem-list
	    (cons fs untranslated-filesystem-list)))))

(defun remove-untranslated-filesystem (filesystem)
  "Record that FILESYSTEM requires CR/LF translation.
FILESYSTEM is a string containing the directory prefix corresponding to
the filesystem.  For example, for a Unix filesystem mounted on drive Z:,
FILESYSTEM could be \"Z:\"."
  (setq untranslated-filesystem-list
	(delete (untranslated-canonical-name filesystem)
		untranslated-filesystem-list)))

(provide 'dos-win32)

;;; dos-win32.el ends here