1;;; dirtrack.el --- Directory Tracking by watching the prompt
2
3;; Copyright (C) 1996, 2001, 2002, 2003, 2004, 2005,
4;;   2006, 2007 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.
133First item is a regexp that describes where to find the path in a prompt.
134Second is a number, the regexp group to match.  Optional third item is
135whether the prompt is multi-line.  If nil or omitted, prompt is assumed to
136be 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.
189Such a directory is all lowercase, has forward-slashes as delimiters,
190and 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.
229The prompt to look for is the first item in `dirtrack-list'.
230
231You can toggle directory tracking by using the function `dirtrack-toggle'.
232
233If directory tracking does not seem to be working, you can use the
234function `dirtrack-debug-toggle' to turn on debugging output.
235
236You 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
294