src/punycode.el

   1 ;;; punycode.el --- An ASCII compatible Unicode encoding format.
   2
   3 ;; Copyright (C) 2003  Simon Josefsson
   4 ;; Keywords: punycode, idna, idn, unicode, encoding
   5
   6 ;; This file is part of GNU Libidn.
   7
   8 ;; GNU Libidn is free software; you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation; either version 2, or (at your option)
  11 ;; any later version.
  12
  13 ;; GNU Libidn is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with GNU Libidn; see the file COPYING.  If not, write to the
  20 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21 ;; Boston, MA 02111-1307, USA.
  22
  23 ;;; Commentary:
  24
  25 ;; A simple wrapper around the command line "idn" utility in GNU
  26 ;; Libidn to make punycode operations available in Emacs.
  27
  28 ;; Example:
  29 ;;
  30 ;; (punycode-encode "räksmörgås")
  31 ;; => "rksmrgs-5wao1o"
  32 ;;
  33 ;; (punycode-encode "foo")
  34 ;; => "foo-"
  35 ;;
  36 ;; (punycode-decode "rksmrgs-5wao1o")
  37 ;; => "räksmörgås"
  38 ;;
  39 ;; (punycode-decode "foo-")
  40 ;; => "foo"
  41
  42 ;; This package is useless unless your emacs has at least partial
  43 ;; support for the UTF-8 coding system.
  44
  45 ;; Report bugs to bug-libidn@gnu.org.
  46
  47 ;;; Code:
  48
  49 (defgroup punycode nil
  50   "Punycode: An ASCII compatible Unicode encoding format.")
  51
  52 (defcustom punycode-program "idn"
  53   "Name of the GNU Libidn \"idn\" application."
  54   :type 'string
  55   :group 'punycode)
  56
  57 (defcustom punycode-environment '("CHARSET=UTF-8")
  58   "List of environment variable definitions prepended to `process-environment'."
  59   :type '(repeat string)
  60   :group 'punycode)
  61
  62 (defcustom punycode-encode-parameters '("--quiet" "--punycode-encode")
  63   "Parameters passed to `punycode-program' to invoke punycode encoding mode."
  64   :type '(repeat string)
  65   :group 'punycode)
  66
  67 (defcustom punycode-decode-parameters '("--quiet" "--punycode-decode")
  68   "Parameters passed to `punycode-program' to invoke punycode decoding mode."
  69   :type '(repeat string)
  70   :group 'punycode)
  71
  72 ;; Internal process handling:
  73
  74 (defvar punycode-encode-process nil
  75   "Internal variable holding process for punycode encoding.")
  76 (defvar punycode-encode-response nil
  77   "Internal variable holding response data received from punycode process.")
  78
  79 (defun punycode-encode-response-clear ()
  80   (setq punycode-encode-response nil))
  81
  82 (defun punycode-encode-response ()
  83   (while (and (eq (process-status punycode-encode-process) 'run)
  84               (null punycode-encode-response))
  85     (accept-process-output punycode-encode-process 1))
  86   punycode-encode-response)
  87
  88 (defun punycode-encode-filter (process string)
  89   (setq punycode-encode-response (concat punycode-encode-response string)))
  90
  91 (defun punycode-encode-process ()
  92   (if (and punycode-encode-process
  93            (eq (process-status punycode-encode-process) 'run))
  94       punycode-encode-process
  95     (if punycode-encode-process
  96         (condition-case ()
  97             (kill-process punycode-encode-process)
  98           (error)))
  99     (when (setq punycode-encode-process
 100                 (let ((process-environment (append punycode-environment
 101                                                    process-environment)))
 102                   (apply 'start-process "punycode" nil punycode-program
 103                          punycode-encode-parameters)))
 104       (set-process-filter punycode-encode-process 'punycode-encode-filter)
 105       (set-process-coding-system punycode-encode-process 'utf-8 'utf-8)
 106       (process-kill-without-query punycode-encode-process))
 107     punycode-encode-process))
 108
 109 (defvar punycode-decode-process nil
 110   "Internal variable holding process for punycode encoding.")
 111 (defvar punycode-decode-response nil
 112   "Internal variable holding response data received from punycode process.")
 113
 114 (defun punycode-decode-response-clear ()
 115   (setq punycode-decode-response nil))
 116
 117 (defun punycode-decode-response ()
 118   (while (and (eq (process-status punycode-decode-process) 'run)
 119               (null punycode-decode-response))
 120     (accept-process-output punycode-decode-process 1))
 121   punycode-decode-response)
 122
 123 (defun punycode-decode-filter (process string)
 124   (setq punycode-decode-response (concat punycode-decode-response string)))
 125
 126 (defun punycode-decode-process ()
 127   (if (and punycode-decode-process
 128            (eq (process-status punycode-decode-process) 'run))
 129       punycode-decode-process
 130     (if punycode-decode-process
 131         (condition-case ()
 132             (kill-process punycode-decode-process)
 133           (error)))
 134     (when (setq punycode-decode-process
 135                 (let ((process-environment (append punycode-environment
 136                                                    process-environment)))
 137                   (apply 'start-process "punycode" nil punycode-program
 138                          punycode-decode-parameters)))
 139       (set-process-filter punycode-decode-process 'punycode-decode-filter)
 140       (set-process-coding-system punycode-decode-process 'utf-8 'utf-8)
 141       (process-kill-without-query punycode-decode-process))
 142     punycode-decode-process))
 143
 144 ;; Punycode Elisp API:
 145
 146 (defun punycode-encode (str)
 147   "Returns a Punycode encoding of STR."
 148   (let ((proc (punycode-encode-process))
 149         string)
 150     (if (null proc)
 151         (error "Cannot start idn application")
 152       (punycode-encode-response-clear)
 153       (process-send-string proc (concat str "\n"))
 154       (setq string (punycode-encode-response))
 155       (if (and string (string= (substring string (1- (length string))) "\n"))
 156           (substring string 0 (1- (length string)))
 157         string))))
 158
 159 (defun punycode-decode (str)
 160   "Returns a possibly multibyte string which is the punycode decoding of STR."
 161   (let ((proc (punycode-decode-process))
 162         string)
 163     (if (null proc)
 164         (error "Cannot start idn application")
 165       (punycode-decode-response-clear)
 166       (process-send-string proc (concat str "\n"))
 167       (setq string (punycode-decode-response))
 168       (if (and string (string= (substring string (1- (length string))) "\n"))
 169           (substring string 0 (1- (length string)))
 170         string))))
 171
 172 (defun punycode-shutdown ()
 173   "Kill the punycode related process."
 174   (interactive)
 175   (if (and punycode-decode-process
 176            (eq (process-status punycode-decode-process) 'run))
 177       (kill-process punycode-decode-process))
 178   (if (and punycode-encode-process
 179            (eq (process-status punycode-encode-process) 'run))
 180       (kill-process punycode-encode-process)))
 181
 182 (provide 'punycode)
 183
 184 ;;; punycode.el ends here