lisp/gnus/gnus-mule.el

   1 ;; gnus-mule.el -- Provide multilingual environment to GNUS
   2
   3 ;; Copyright (C) 1995 Free Software Foundation, Inc.
   4 ;; Copyright (C) 1995 Electrotechnical Laboratory, JAPAN.
   5
   6 ;; Keywords: gnus, mule
   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
  22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This package enables GNUS to code convert automatically
  27 ;; accoding to a coding system specified for each news group.
  28 ;; Please put the following line in your .emacs:
  29 ;;      (add-hook 'gnus-startup-hook 'gnus-mule-initialize)
  30 ;; If you want to specify some coding system for a specific news
  31 ;; group, add the fllowing line in your .emacs:
  32 ;;      (gnus-mule-add-group "xxx.yyy.zzz" 'some-coding-system)
  33 ;;
  34 ;; Decoding of summary buffer is not yet implemented.
  35
  36 (require 'gnus)
  37
  38 (defvar gnus-newsgroup-coding-systems nil
  39   "Assoc list of news groups vs corresponding coding systems.
  40 Each element is a list of news group name and cons of coding systems
  41 for reading and posting.")
  42
  43 ;;;###autoload
  44 (defun gnus-mule-add-group (name coding-system)
  45   "Specify that articles of news group NAME are encoded in CODING-SYSTEM.
  46 All news groups deeper than NAME are also the target.
  47 If CODING-SYSTEM is a cons, the car and cdr part are regarded as
  48 coding-system for reading and writing respectively."
  49   (if (not (consp coding-system))
  50       (setq coding-system (cons coding-system coding-system)))
  51   (setq name (concat "^" (regexp-quote name)))
  52   (let ((group (assoc name gnus-newsgroup-coding-systems)))
  53     (if group
  54         (setcdr group coding-system)
  55       (setq gnus-newsgroup-coding-systems
  56             (cons (cons name coding-system) gnus-newsgroup-coding-systems)))))
  57
  58 (defun gnus-mule-get-coding-system (group)
  59   "Return the coding system for news group GROUP."
  60   (let ((groups gnus-newsgroup-coding-systems)
  61         (len -1)
  62         coding-system)
  63     ;; Find an entry which matches GROUP the best (i.e. longest).
  64     (while groups
  65       (if (and (string-match (car (car groups)) group)
  66                (> (match-end 0) len))
  67           (setq len (match-end 0)
  68                 coding-system (cdr (car groups))))
  69       (setq groups (cdr groups)))
  70     coding-system))
  71
  72 ;; Flag to indicate if article buffer is already decoded or not.")
  73 (defvar gnus-mule-article-decoded nil)
  74 ;; Codingsystem for reading articles of the current news group.
  75 (defvar gnus-mule-coding-system nil)
  76 (defvar gnus-mule-subject nil)
  77 (defvar gnus-mule-decoded-subject nil)
  78 (defvar gnus-mule-original-subject nil)
  79
  80 ;; Encode (if ENCODING is t) or decode (if ENCODING is nil)  the
  81 ;; region from START to END by CODING-SYSTEM.
  82 (defun gnus-mule-code-convert1 (start end coding-system encoding)
  83   (if (< start end)
  84       (save-excursion
  85        (if encoding
  86            (encode-coding-region start end coding-system)
  87          (decode-coding-region start end coding-system)))))
  88
  89 ;; Encode (if ENCODING is t) or decode (if ENCODING is nil) the
  90 ;; current buffer by CODING-SYSTEM.  Try not to move positions of
  91 ;; (window-start) and (point).
  92 (defun gnus-mule-code-convert (coding-system encoding)
  93   (if coding-system
  94       (let ((win (get-buffer-window (current-buffer))))
  95         (if win
  96             ;; We should keep (point) and (window-start).
  97             (save-window-excursion
  98               (select-window win)
  99               (if encoding
 100                   ;; Simple way to assure point is on valid character boundary.
 101                   (beginning-of-line))
 102               (gnus-mule-code-convert1 (point-min) (window-start)
 103                                        coding-system encoding)
 104               (gnus-mule-code-convert1 (window-start) (point)
 105                                        coding-system encoding)
 106               (gnus-mule-code-convert1 (point) (point-max)
 107                                        coding-system encoding)
 108               (if (not (pos-visible-in-window-p))
 109                   ;; point went out of window, move to the bottom of window.
 110                   (move-to-window-line -1)))
 111           ;; No window for the buffer, no need to worry about (point)
 112           ;; and (windos-start).
 113           (gnus-mule-code-convert1 (point-min) (point-max)
 114                                    coding-system encoding))
 115         )))
 116
 117 ;; Set `gnus-mule-coding-system' to the coding system articles of the
 118 ;; current news group is encoded.   This function is set in
 119 ;; `gnus-select-group-hook'.
 120 (defun gnus-mule-select-coding-system ()
 121   (let ((coding-system (gnus-mule-get-coding-system gnus-newsgroup-name)))
 122     (setq gnus-mule-coding-system
 123           (if (and coding-system (coding-system-p (car coding-system)))
 124               (car coding-system)))))
 125
 126 ;; Decode the current article.  This function is set in
 127 ;; `gnus-article-prepare-hook'.
 128 (defun gnus-mule-decode-article ()
 129   (gnus-mule-code-convert gnus-mule-coding-system nil)
 130   (setq gnus-mule-article-decoded t))
 131
 132 ;; Decode the current summary buffer.  This function is set in
 133 ;; `gnus-summary-prepare-hook'.
 134 (defun gnus-mule-decode-summary ()
 135   ;; I have not yet implemented this function because I'm not yet
 136   ;; familiar with the new Gnus codes, especialy how to extract only
 137   ;; subjects from a summary buffer.
 138   nil)
 139
 140 (defun gnus-mule-toggle-article-format ()
 141   "Toggle decoding/encoding of the current article buffer."
 142   (interactive)
 143   (let ((buf (get-buffer gnus-article-buffer)))
 144     (if (and gnus-mule-coding-system buf)
 145         (save-excursion
 146           (set-buffer buf)
 147           (let ((modif (buffer-modified-p))
 148                 buffer-read-only)
 149             (gnus-mule-code-convert gnus-mule-coding-system
 150                                    gnus-mule-article-decoded)
 151             (setq gnus-mule-article-decoded (not gnus-mule-article-decoded))
 152             (set-buffer-modified-p modif))))))
 153
 154 ;;;###autoload
 155 (defun gnus-mule-initialize ()
 156   "Do several settings for GNUS to enable automatic code conversion."
 157   ;; Convenient key definitions
 158   (define-key gnus-article-mode-map "z" 'gnus-mule-toggle-article-format)
 159   (define-key gnus-summary-mode-map "z" 'gnus-mule-toggle-article-format)
 160   ;; Hook definition
 161   (add-hook 'gnus-select-group-hook 'gnus-mule-select-coding-system)
 162   (add-hook 'gnus-summary-prepare-hook 'gnus-mule-decode-summary)
 163   (add-hook 'gnus-article-prepare-hook 'gnus-mule-decode-article))
 164
 165 (gnus-mule-add-group "" 'coding-system-iso-2022-7) ;; default coding system
 166 (gnus-mule-add-group "alt" 'no-conversion)
 167 (gnus-mule-add-group "comp" 'no-conversion)
 168 (gnus-mule-add-group "gnu" 'no-conversion)
 169 (gnus-mule-add-group "rec" 'no-conversion)
 170 (gnus-mule-add-group "sci" 'no-conversion)
 171 (gnus-mule-add-group "soc" 'no-conversion)
 172 (gnus-mule-add-group "alt.chinese.text" 'coding-system-hz)
 173 (gnus-mule-add-group "alt.hk" 'coding-system-hz)
 174 (gnus-mule-add-group "alt.chinese.text.big5" 'coding-system-big5)
 175 (gnus-mule-add-group "soc.culture.vietnamese" '(nil . coding-system-viqr))
 176
 177 (add-hook 'gnus-startup-hook 'gnus-mule-initialize)
 178
 179 ;; gnus-mule.el ends here