lisp/net/zone-mode.el

   1 ;;; zone-mode.el --- major mode for editing DNS zone files
   2
   3 ;; Copyright (C) 1998 Free Software Foundation, Inc.
   4
   5 ;; Author: John Heidemann <johnh@isi.edu>
   6 ;; Keywords: DNS, languages
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;;;
  28 ;;; See the comments in ``define-derived-mode zone-mode''
  29 ;;; (the last function in this file)
  30 ;;; for what this mode is and how to use it automatically.
  31 ;;;
  32
  33 ;;;
  34 ;;; Credits:
  35 ;;; Zone-mode was written by John Heidemann <johnh@isi.edu>,
  36 ;;; with bug fixes from Simon Leinen <simon@limmat.switch.ch>.
  37 ;;;
  38
  39 ;;; Code:
  40
  41 (defun zone-mode-update-serial ()
  42   "Update the serial number in a zone."
  43   (interactive)
  44   (save-excursion
  45     (goto-char (point-min))
  46     (while (re-search-forward "\\b\\([0-9]+\\)\\([0-9][0-9]\\)\\([ \t]+;[ \t]+[Ss]erial\\)" (point-max) t)
  47       (let* ((old-date (match-string 1))
  48              (old-seq (match-string 2))
  49              (old-seq-num (string-to-number (match-string 2)))
  50              (old-flag (match-string 3))
  51              (cur-date (format-time-string "%Y%m%d"))
  52              (new-seq
  53               (cond
  54                ((not (string= old-date cur-date))
  55                 "00") ;; reset sequence number
  56                ((>= old-seq-num 99)
  57                 (error "Serial number's sequence cannot increment beyond 99"))
  58                (t
  59                 (format "%02d" (1+ old-seq-num)))))
  60              (old-serial (concat old-date old-seq))
  61              (new-serial (concat cur-date new-seq)))
  62         (if (string-lessp new-serial old-serial)
  63             (error (format "Serial numbers want to move backwards from %s to %s" old-serial new-serial))
  64           (replace-match (concat cur-date new-seq old-flag) t t))))))
  65
  66 ;;;###autoload
  67 (defun zone-mode-update-serial-hook ()
  68   "Update the serial number in a zone if the file was modified."
  69   (interactive)
  70   (if (buffer-modified-p (current-buffer))
  71       (zone-mode-update-serial))
  72   nil ;; so we can run from write-file-hooks
  73   )
  74
  75 (defvar zone-mode-syntax-table nil
  76   "Zone-mode's syntax table.")
  77
  78 (defun zone-mode-load-time-setup ()
  79   "Initialise `zone-mode' stuff."
  80   (setq zone-mode-syntax-table (make-syntax-table))
  81   (modify-syntax-entry ?\; "<" zone-mode-syntax-table)
  82   (modify-syntax-entry ?\n ">" zone-mode-syntax-table))
  83
  84 ;;;###autoload
  85 (define-derived-mode zone-mode fundamental-mode "zone"
  86   "A mode for editing DNS zone files.
  87
  88 Zone-mode does two things:
  89
  90         - automatically update the serial number for a zone
  91                 when saving the file
  92
  93         - fontification"
  94
  95   (add-hook 'write-file-hooks 'zone-mode-update-serial-hook nil t)
  96
  97   (if (null zone-mode-syntax-table)
  98       (zone-mode-load-time-setup)) ;; should have been run at load-time
  99
 100   ;; font-lock support:
 101   (set-syntax-table zone-mode-syntax-table)
 102   (make-local-variable 'comment-start)
 103   (setq comment-start ";")
 104   (make-local-variable 'comment-start-skip)
 105   ;; Look within the line for a ; following an even number of backslashes
 106   ;; after either a non-backslash or the line beginning.
 107   (setq comment-start-skip "\\(\\(^\\|[^\\\\\n]\\)\\(\\\\\\\\\\)*\\);+[ \t]*")
 108   (make-local-variable 'comment-column)
 109   (setq comment-column 40)
 110   (make-local-variable 'font-lock-defaults)
 111   (setq font-lock-defaults
 112         '(nil nil nil nil beginning-of-line)))
 113
 114 (zone-mode-load-time-setup)
 115
 116 (provide 'zone-mode)
 117
 118 ;;; zone-mode.el ends here