lisp/dirtrack.el

   1 ;;; dirtrack.el --- Directory Tracking by watching the prompt
   2
   3 ;; Copyright (C) 1996, 2002, 2003, 2004, 2005,
   4 ;;   2006 Free Software Foundation, Inc.
   5
   6 ;; Author: Peter Breton <pbreton@cs.umb.edu>
   7 ;; Created: Sun Nov 17 1996
   8 ;; Keywords: processes
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  24 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  25 ;; Boston, MA 02110-1301, USA.
  26
  27 ;;; Commentary:
  28
  29 ;; Shell directory tracking by watching the prompt.
  30 ;;
  31 ;; This is yet another attempt at a directory-tracking package for
  32 ;; Emacs shell-mode.  However, this package makes one strong assumption:
  33 ;; that you can customize your shell's prompt to contain the
  34 ;; current working directory.  Most shells do support this, including
  35 ;; almost every type of Bourne and C shell on Unix, the native shells on
  36 ;; Windows95 (COMMAND.COM) and Windows NT (CMD.EXE), and most 3rd party
  37 ;; Windows shells.  If you cannot do this, or do not wish to, this package
  38 ;; will be useless to you.
  39 ;;
  40 ;; Installation:
  41 ;;
  42 ;; 1) Set your shell's prompt to contain the current working directory.
  43 ;; You may need to consult your shell's documentation to find out how to
  44 ;; do this.
  45 ;;
  46 ;; Note that directory tracking is done by matching regular expressions,
  47 ;; therefore it is *VERY IMPORTANT* for your prompt to be easily
  48 ;; distinguishable from other output.  If your prompt regexp is too general,
  49 ;; you will see error messages from the dirtrack filter as it attempts to cd
  50 ;; to non-existent directories.
  51 ;;
  52 ;; 2) Set the variable `dirtrack-list' to an appropriate value.  This
  53 ;; should be a list of two elements: the first is a regular expression
  54 ;; which matches your prompt up to and including the pathname part.
  55 ;; The second is a number which tells which regular expression group to
  56 ;; match to extract only the pathname.  If you use a multi-line prompt,
  57 ;; add 't' as a third element.  Note that some of the functions in
  58 ;; 'comint.el' assume a single-line prompt (eg, comint-bol).
  59 ;;
  60 ;; Determining this information may take some experimentation.  Setting
  61 ;; the variable `dirtrack-debug' may help; it causes the directory-tracking
  62 ;; filter to log messages to the buffer `dirtrack-debug-buffer'.  You can easily
  63 ;; toggle this setting with the `dirtrack-debug-toggle' function.
  64 ;;
  65 ;; 3) Add a hook to shell-mode to enable the directory tracking:
  66 ;;
  67 ;; (add-hook 'shell-mode-hook
  68 ;;   (lambda () (add-hook 'comint-preoutput-filter-functions 'dirtrack nil t)))
  69 ;;
  70 ;; You may wish to turn ordinary shell tracking off by calling
  71 ;; `shell-dirtrack-toggle' or setting `shell-dirtrackp'.
  72 ;;
  73 ;; Examples:
  74 ;;
  75 ;; 1) On Windows NT, my prompt is set to emacs$S$P$G.
  76 ;; 'dirtrack-list' is set to (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
  77 ;;
  78 ;; 2) On Solaris running bash, my prompt is set like this:
  79 ;;    PS1="\w\012emacs@\h(\!) [\t]% "
  80 ;;    'dirtrack-list' is set to (list "^\\([/~].*\\)\nemacs@[^%]+% *" 1 t)
  81 ;;
  82 ;; I'd appreciate other examples from people who use this package.
  83 ;;
  84 ;; Here's one from Stephen Eglen:
  85 ;;
  86 ;;   Running under tcsh:
  87 ;;   (setq-default dirtrack-list '("^%E \\([^ ]+\\)" 1))
  88 ;;
  89 ;;   It might be worth mentioning in your file that emacs sources start up
  90 ;;   files of the form: ~/.emacs_<SHELL> where <SHELL> is the name of the
  91 ;;   shell.  So for example, I have the following in ~/.emacs_tcsh:
  92 ;;
  93 ;;   set prompt = "%%E %~ %h% "
  94 ;;
  95 ;;   This produces a prompt of the form:
  96 ;;   %E /var/spool 10%
  97 ;;
  98 ;;   This saves me from having to use the %E prefix in other non-emacs
  99 ;;   shells.
 100 ;;
 101 ;; A final note:
 102 ;;
 103 ;;   I run LOTS of shell buffers through Emacs, sometimes as different users
 104 ;;   (eg, when logged in as myself, I'll run a root shell in the same Emacs).
 105 ;;   If you do this, and the shell prompt contains a ~, Emacs will interpret
 106 ;;   this relative to the user which owns the Emacs process, not the user
 107 ;;   who owns the shell buffer.  This may cause dirtrack to behave strangely
 108 ;;   (typically it reports that it is unable to cd to a directory
 109 ;;   with a ~ in it).
 110 ;;
 111 ;;   The same behavior can occur if you use dirtrack with remote filesystems
 112 ;;   (using telnet, rlogin, etc) as Emacs will be checking the local
 113 ;;   filesystem, not the remote one.  This problem is not specific to dirtrack,
 114 ;;   but also affects file completion, etc.
 115
 116 ;;; Code:
 117
 118 (eval-when-compile
 119   (require 'comint)
 120   (require 'shell))
 121
 122 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 123 ;; Customization Variables
 124 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 125
 126 (defgroup dirtrack nil
 127   "Directory tracking by watching the prompt."
 128   :prefix "dirtrack-"
 129   :group 'shell)
 130
 131 (defcustom dirtrack-list (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
 132   "List for directory tracking.
 133 First item is a regexp that describes where to find the path in a prompt.
 134 Second is a number, the regexp group to match.  Optional third item is
 135 whether the prompt is multi-line.  If nil or omitted, prompt is assumed to
 136 be on a single line."
 137   :group 'dirtrack
 138   :type  '(sexp (regexp  :tag "Prompt Expression")
 139                 (integer :tag "Regexp Group")
 140                 (boolean :tag "Multiline Prompt")))
 141
 142 (make-variable-buffer-local 'dirtrack-list)
 143
 144 (defcustom dirtrack-debug nil
 145   "If non-nil, the function `dirtrack' will report debugging info."
 146   :group 'dirtrack
 147   :type  'boolean)
 148
 149 (defcustom dirtrack-debug-buffer "*Directory Tracking Log*"
 150   "Buffer to write directory tracking debug information."
 151   :group 'dirtrack
 152   :type  'string)
 153
 154 (defcustom dirtrackp t
 155   "If non-nil, directory tracking via `dirtrack' is enabled."
 156   :group 'dirtrack
 157   :type  'boolean)
 158
 159 (make-variable-buffer-local 'dirtrackp)
 160
 161 (defcustom dirtrack-directory-function
 162   (if (memq system-type (list 'ms-dos 'windows-nt 'cygwin))
 163       'dirtrack-windows-directory-function
 164     'file-name-as-directory)
 165   "Function to apply to the prompt directory for comparison purposes."
 166   :group 'dirtrack
 167   :type  'function)
 168
 169 (defcustom dirtrack-canonicalize-function
 170   (if (memq system-type (list 'ms-dos 'windows-nt 'cygwin))
 171       'downcase 'identity)
 172   "Function to apply to the default directory for comparison purposes."
 173   :group 'dirtrack
 174   :type  'function)
 175
 176 (defcustom dirtrack-directory-change-hook nil
 177   "Hook that is called when a directory change is made."
 178   :group 'dirtrack
 179   :type 'hook)
 180
 181
 182 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 183 ;; Functions
 184 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 185
 186
 187 (defun dirtrack-windows-directory-function (dir)
 188   "Return a canonical directory for comparison purposes.
 189 Such a directory is all lowercase, has forward-slashes as delimiters,
 190 and ends with a forward slash."
 191   (file-name-as-directory (downcase (subst-char-in-string ?\\ ?/ dir))))
 192
 193 (defun dirtrack-cygwin-directory-function (dir)
 194   "Return a canonical directory taken from a Cygwin path for comparison purposes."
 195   (if (string-match "/cygdrive/\\([A-Z]\\)\\(.*\\)" dir)
 196       (concat (match-string 1 dir) ":" (match-string 2 dir))
 197     dir))
 198
 199 ;; Copied from shell.el
 200 (defun dirtrack-toggle ()
 201   "Enable or disable Dirtrack directory tracking in a shell buffer."
 202   (interactive)
 203   (if (setq dirtrackp (not dirtrackp))
 204       (add-hook 'comint-preoutput-filter-functions 'dirtrack nil t)
 205     (remove-hook 'comint-preoutput-filter-functions 'dirtrack t))
 206   (message "Directory tracking %s" (if dirtrackp "ON" "OFF")))
 207
 208 (defun dirtrack-debug-toggle ()
 209   "Enable or disable Dirtrack debugging."
 210   (interactive)
 211   (setq dirtrack-debug (not dirtrack-debug))
 212   (message "Directory debugging %s" (if dirtrack-debug "ON" "OFF"))
 213   (and dirtrack-debug
 214        (display-buffer (get-buffer-create dirtrack-debug-buffer))))
 215
 216 (defun dirtrack-debug-message (string)
 217   (let ((buf (current-buffer))
 218         (debug-buf (get-buffer-create dirtrack-debug-buffer))
 219         )
 220     (set-buffer debug-buf)
 221     (goto-char (point-max))
 222     (insert (concat string "\n"))
 223     (set-buffer buf)
 224   ))
 225
 226 ;;;###autoload
 227 (defun dirtrack (input)
 228   "Determine the current directory by scanning the process output for a prompt.
 229 The prompt to look for is the first item in `dirtrack-list'.
 230
 231 You can toggle directory tracking by using the function `dirtrack-toggle'.
 232
 233 If directory tracking does not seem to be working, you can use the
 234 function `dirtrack-debug-toggle' to turn on debugging output.
 235
 236 You can enable directory tracking by adding this function to
 237 `comint-output-filter-functions'."
 238   (if (or (null dirtrackp)
 239           ;; No output?
 240           (eq (point) (point-min)))
 241       nil
 242     (let (prompt-path
 243           (current-dir default-directory)
 244           (dirtrack-regexp    (nth 0 dirtrack-list))
 245           (match-num          (nth 1 dirtrack-list))
 246           ;; Currently unimplemented, it seems.  --Stef
 247           (multi-line         (nth 2 dirtrack-list)))
 248       (save-excursion
 249         ;; No match
 250         (if (null (string-match dirtrack-regexp input))
 251             (and dirtrack-debug
 252                  (dirtrack-debug-message
 253                   (format
 254                    "Input `%s' failed to match `dirtrack-regexp'" input)))
 255           (setq prompt-path (match-string match-num input))
 256           ;; Empty string
 257           (if (not (> (length prompt-path) 0))
 258               (and dirtrack-debug
 259                    (dirtrack-debug-message "Match is empty string"))
 260             ;; Transform prompts into canonical forms
 261             (setq prompt-path (funcall dirtrack-directory-function
 262                                        prompt-path))
 263             (setq current-dir (funcall dirtrack-canonicalize-function
 264                                        current-dir))
 265             (and dirtrack-debug
 266                  (dirtrack-debug-message
 267                   (format
 268                    "Prompt is %s\nCurrent directory is %s"
 269                    prompt-path current-dir)))
 270             ;; Compare them
 271             (if (or (string= current-dir prompt-path)
 272                     (string= current-dir
 273                              (abbreviate-file-name prompt-path)))
 274                 (and dirtrack-debug
 275                      (dirtrack-debug-message
 276                       (format "Not changing directory")))
 277               ;; It's possible that Emacs will think the directory
 278               ;; won't exist (eg, rlogin buffers)
 279               (if (file-accessible-directory-p prompt-path)
 280                   ;; Change directory
 281                   (and (shell-process-cd prompt-path)
 282                        (run-hooks 'dirtrack-directory-change-hook)
 283                        dirtrack-debug
 284                        (dirtrack-debug-message
 285                         (format "Changing directory to %s" prompt-path)))
 286                 (error "Directory %s does not exist" prompt-path)))
 287             )))))
 288   input)
 289
 290 (provide 'dirtrack)
 291
 292 ;; arch-tag: 168de071-be88-4937-aff6-2aba9f328d5a
 293 ;;; dirtrack.el ends here