lisp/dirtrack.el

   1 ;;; dirtrack.el --- Directory Tracking by watching the prompt
   2
   3 ;; Copyright (C) 1996 Free Software Foundation, Inc.
   4
   5 ;; Author: Peter Breton <pbreton@cs.umb.edu>
   6 ;; Created: Sun Nov 17 1996
   7 ;; Keywords: processes
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; Shell directory tracking by watching the prompt.
  29 ;;
  30 ;; This is yet another attempt at a directory-tracking package for
  31 ;; Emacs shell-mode. However, this package makes one strong assumption:
  32 ;; that you can customize your shell's prompt to contain the
  33 ;; current working directory. Most shells do support this, including
  34 ;; almost every type of Bourne and C shell on Unix, the native shells on
  35 ;; Windows95 (COMMAND.COM) and Windows NT (CMD.EXE), and most 3rd party
  36 ;; Windows shells. If you cannot do this, or do not wish to, this package
  37 ;; will be useless to you.
  38 ;;
  39 ;; Installation:
  40 ;;
  41 ;; 1) Set your shell's prompt to contain the current working directory.
  42 ;; You may need to consult your shell's documentation to find out how to
  43 ;; do this.
  44 ;;
  45 ;; Note that directory tracking is done by matching regular expressions,
  46 ;; therefore it is *VERY IMPORTANT* for your prompt to be easily
  47 ;; distinguishable from other output. If your prompt regexp is too general,
  48 ;; you will see error messages from the dirtrack filter as it attempts to cd
  49 ;; to non-existent directories.
  50 ;;
  51 ;; 2) Set the variable `dirtrack-list' to an appropriate value. This
  52 ;; should be a list of two elements: the first is a regular expression
  53 ;; which matches your prompt up to and including the pathname part.
  54 ;; The second is a number which tells which regular expression group to
  55 ;; match to extract only the pathname. If you use a multi-line prompt,
  56 ;; add 't' as a third element. Note that some of the functions in
  57 ;; 'comint.el' assume a single-line prompt (eg, comint-bol).
  58 ;;
  59 ;; Determining this information may take some experimentation. Setting
  60 ;; the variable `dirtrack-debug' may help; it causes the directory-tracking
  61 ;; filter to log messages to the buffer `dirtrack-debug-buffer'. You can easily
  62 ;; toggle this setting with the `dirtrack-debug-toggle' function.
  63 ;;
  64 ;; 3) Add a hook to shell-mode to enable the directory tracking:
  65 ;;
  66 ;; (add-hook 'shell-mode-hook
  67 ;;   (function (lambda ()
  68 ;;            (setq comint-preoutput-filter-functions
  69 ;;                  (append (list 'dirtrack)
  70 ;;                          comint-preoutput-filter-functions)))))
  71 ;;
  72 ;; You may wish to turn ordinary shell tracking off by calling
  73 ;; `shell-dirtrack-toggle' or setting `shell-dirtrackp'.
  74 ;;
  75 ;; Examples:
  76 ;;
  77 ;; 1) On Windows NT, my prompt is set to emacs$S$P$G.
  78 ;; 'dirtrack-list' is set to (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
  79 ;;
  80 ;; 2) On Solaris running bash, my prompt is set like this:
  81 ;;    PS1="\w\012emacs@\h(\!) [\t]% "
  82 ;;    'dirtrack-list' is set to (list "^\\([/~].*\\)\nemacs@[^%]+% *" 1 t)
  83 ;;
  84 ;; I'd appreciate other examples from people who use this package.
  85 ;;
  86 ;; Here's one from Stephen Eglen:
  87 ;;
  88 ;;   Running under tcsh:
  89 ;;   (setq-default dirtrack-list '("^%E \\([^ ]+\\)" 1))
  90 ;;
  91 ;;   It might be worth mentioning in your file that emacs sources start up
  92 ;;   files of the form: ~/.emacs_<SHELL> where <SHELL> is the name of the
  93 ;;   shell.  So for example, I have the following in ~/.emacs_tcsh:
  94 ;;
  95 ;;   set prompt = "%%E %~ %h% "
  96 ;;
  97 ;;   This produces a prompt of the form:
  98 ;;   %E /var/spool 10%
  99 ;;
 100 ;;   This saves me from having to use the %E prefix in other non-emacs
 101 ;;   shells.
 102 ;;
 103 ;; A final note:
 104 ;;
 105 ;;   I run LOTS of shell buffers through Emacs, sometimes as different users
 106 ;;   (eg, when logged in as myself, I'll run a root shell in the same Emacs).
 107 ;;   If you do this, and the shell prompt contains a ~, Emacs will interpret
 108 ;;   this relative to the user which owns the Emacs process, not the user
 109 ;;   who owns the shell buffer. This may cause dirtrack to behave strangely
 110 ;;   (typically it reports that it is unable to cd to a directory
 111 ;;   with a ~ in it).
 112 ;;
 113 ;;   The same behavior can occur if you use dirtrack with remote filesystems
 114 ;;   (using telnet, rlogin, etc) as Emacs will be checking the local
 115 ;;   filesystem, not the remote one. This problem is not specific to dirtrack,
 116 ;;   but also affects file completion, etc.
 117
 118 ;;; Code:
 119
 120 (eval-when-compile
 121   (require 'comint)
 122   (require 'shell))
 123
 124 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 125 ;; Customization Variables
 126 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 127
 128 (defgroup dirtrack nil
 129   "Directory tracking by watching the prompt."
 130   :prefix "dirtrack-"
 131   :group 'shell)
 132
 133 (defcustom dirtrack-list (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
 134   "*List for directory tracking.
 135 First item is a regexp that describes where to find the path in a prompt.
 136 Second is a number, the regexp group to match. Optional third item is
 137 whether the prompt is multi-line. If nil or omitted, prompt is assumed to
 138 be on a single line."
 139   :group 'dirtrack
 140   :type  '(sexp (regexp  :tag "Prompt Expression")
 141                 (integer :tag "Regexp Group")
 142                 (boolean :tag "Multiline Prompt")
 143                 )
 144   )
 145
 146 (make-variable-buffer-local 'dirtrack-list)
 147
 148 (defcustom dirtrack-debug nil
 149   "*If non-nil, the function `dirtrack' will report debugging info."
 150   :group 'dirtrack
 151   :type  'boolean
 152   )
 153
 154 (defcustom dirtrack-debug-buffer "*Directory Tracking Log*"
 155   "Buffer to write directory tracking debug information."
 156   :group 'dirtrack
 157   :type  'string
 158   )
 159
 160 (defcustom dirtrackp t
 161   "*If non-nil, directory tracking via `dirtrack' is enabled."
 162   :group 'dirtrack
 163   :type  'boolean
 164   )
 165
 166 (make-variable-buffer-local 'dirtrackp)
 167
 168 (defcustom dirtrack-directory-function
 169   (if (memq system-type (list 'ms-dos 'windows-nt 'cygwin))
 170       'dirtrack-windows-directory-function
 171     'dirtrack-default-directory-function)
 172   "*Function to apply to the prompt directory for comparison purposes."
 173   :group 'dirtrack
 174   :type  'function
 175   )
 176
 177 (defcustom dirtrack-canonicalize-function
 178   (if (memq system-type (list 'ms-dos 'windows-nt 'cygwin))
 179       'downcase 'identity)
 180   "*Function to apply to the default directory for comparison purposes."
 181   :group 'dirtrack
 182   :type  'function
 183   )
 184
 185 (defcustom dirtrack-directory-change-hook nil
 186   "Hook that is called when a directory change is made."
 187   :group 'dirtrack
 188   :type 'hook
 189   )
 190
 191
 192 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 193 ;; Functions
 194 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 195
 196 (defun dirtrack-default-directory-function (dir)
 197   "Return a canonical directory for comparison purposes.
 198 Such a directory ends with a forward slash."
 199   (let ((directory dir))
 200     (if (not (char-equal ?/ (string-to-char (substring directory -1))))
 201         (concat directory "/")
 202       directory)))
 203
 204 (defun dirtrack-windows-directory-function (dir)
 205   "Return a canonical directory for comparison purposes.
 206 Such a directory is all lowercase, has forward-slashes as delimiters,
 207 and ends with a forward slash."
 208   (let ((directory dir))
 209     (setq directory (downcase (dirtrack-replace-slash directory t)))
 210     (if (not (char-equal ?/ (string-to-char (substring directory -1))))
 211         (concat directory "/")
 212       directory)))
 213
 214 (defun dirtrack-cygwin-directory-function (dir)
 215   "Return a canonical directory taken from a Cygwin path for comparison purposes."
 216   (if (string-match "/cygdrive/\\([A-Z]\\)\\(.*\\)" dir)
 217       (concat (match-string 1 dir) ":" (match-string 2 dir))
 218     dir))
 219
 220 (defconst dirtrack-forward-slash  (regexp-quote "/"))
 221 (defconst dirtrack-backward-slash (regexp-quote "\\"))
 222
 223 (defun dirtrack-replace-slash (string &optional opposite)
 224   "Replace forward slashes with backwards ones.
 225 If additional argument is non-nil, replace backwards slashes with
 226 forward ones."
 227   (let ((orig     (if opposite
 228                       dirtrack-backward-slash
 229                     dirtrack-forward-slash))
 230         (replace  (if opposite
 231                       dirtrack-forward-slash
 232                     dirtrack-backward-slash))
 233         (newstring string)
 234         )
 235     (while (string-match orig newstring)
 236       (setq newstring (replace-match replace nil t newstring)))
 237   newstring))
 238
 239 ;; Copied from shell.el
 240 (defun dirtrack-toggle ()
 241   "Enable or disable Dirtrack directory tracking in a shell buffer."
 242   (interactive)
 243   (setq dirtrackp (not dirtrackp))
 244   (message "Directory tracking %s" (if dirtrackp "ON" "OFF")))
 245
 246 (defun dirtrack-debug-toggle ()
 247   "Enable or disable Dirtrack debugging."
 248   (interactive)
 249   (setq dirtrack-debug (not dirtrack-debug))
 250   (message "Directory debugging %s" (if dirtrack-debug "ON" "OFF"))
 251   (and dirtrack-debug
 252        (display-buffer (get-buffer-create dirtrack-debug-buffer))))
 253
 254 (defun dirtrack-debug-message (string)
 255   (let ((buf (current-buffer))
 256         (debug-buf (get-buffer-create dirtrack-debug-buffer))
 257         )
 258     (set-buffer debug-buf)
 259     (goto-char (point-max))
 260     (insert (concat string "\n"))
 261     (set-buffer buf)
 262   ))
 263
 264 ;;;###autoload
 265 (defun dirtrack (input)
 266   "Determine the current directory by scanning the process output for a prompt.
 267 The prompt to look for is the first item in `dirtrack-list'.
 268
 269 You can toggle directory tracking by using the function `dirtrack-toggle'.
 270
 271 If directory tracking does not seem to be working, you can use the
 272 function `dirtrack-debug-toggle' to turn on debugging output.
 273
 274 You can enable directory tracking by adding this function to
 275 `comint-output-filter-functions'.
 276 "
 277   (if (null dirtrackp)
 278       nil
 279     (let (prompt-path
 280           matched
 281           (current-dir default-directory)
 282           (dirtrack-regexp    (nth 0 dirtrack-list))
 283           (match-num          (nth 1 dirtrack-list))
 284           (multi-line         (nth 2 dirtrack-list))
 285           )
 286       ;; No output?
 287       (if (eq (point) (point-min))
 288           nil
 289         (save-excursion
 290           (setq matched (string-match dirtrack-regexp input)))
 291           ;; No match
 292           (if (null matched)
 293               (and dirtrack-debug
 294                    (dirtrack-debug-message
 295                     (format
 296                      "Input `%s' failed to match regexp: %s"
 297                     input dirtrack-regexp)))
 298             (setq prompt-path
 299                   (substring input
 300                    (match-beginning match-num) (match-end match-num)))
 301             ;; Empty string
 302             (if (not (> (length prompt-path) 0))
 303                 (and dirtrack-debug
 304                      (dirtrack-debug-message "Match is empty string"))
 305               ;; Transform prompts into canonical forms
 306               (setq prompt-path (funcall dirtrack-directory-function
 307                                          prompt-path))
 308               (setq current-dir (funcall dirtrack-canonicalize-function
 309                                          current-dir))
 310               (and dirtrack-debug
 311                    (dirtrack-debug-message
 312                     (format
 313                      "Prompt is %s\nCurrent directory is %s"
 314                      prompt-path current-dir)))
 315               ;; Compare them
 316               (if (or (string= current-dir prompt-path)
 317                       (string= current-dir
 318                                (abbreviate-file-name prompt-path)))
 319                   (and dirtrack-debug
 320                        (dirtrack-debug-message
 321                         (format "Not changing directory")))
 322                 ;; It's possible that Emacs will think the directory
 323                 ;; won't exist (eg, rlogin buffers)
 324                 (if (file-accessible-directory-p prompt-path)
 325                     ;; Change directory
 326                     (and (shell-process-cd prompt-path)
 327                          (run-hooks 'dirtrack-directory-change-hook)
 328                          dirtrack-debug
 329                          (dirtrack-debug-message
 330                           (format "Changing directory to %s" prompt-path)))
 331                   (error "Directory %s does not exist" prompt-path)))
 332               )))))
 333   input)
 334
 335 (provide 'dirtrack)
 336
 337 ;;; dirtrack.el ends here