lisp/dirtrack.el

   1 ;;; dirtrack.el --- Directory Tracking by watching the prompt
   2
   3 ;; Copyright (C) 1996, 2001-2011 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 3 of the License, or
  14 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Shell directory tracking by watching the prompt.
  27 ;;
  28 ;; This is yet another attempt at a directory-tracking package for
  29 ;; Emacs shell-mode.  However, this package makes one strong assumption:
  30 ;; that you can customize your shell's prompt to contain the
  31 ;; current working directory.  Most shells do support this, including
  32 ;; almost every type of Bourne and C shell on Unix, the native shells on
  33 ;; Windows95 (COMMAND.COM) and Windows NT (CMD.EXE), and most 3rd party
  34 ;; Windows shells.  If you cannot do this, or do not wish to, this package
  35 ;; will be useless to you.
  36 ;;
  37 ;; Installation:
  38 ;;
  39 ;; 1) Set your shell's prompt to contain the current working directory.
  40 ;; You may need to consult your shell's documentation to find out how to
  41 ;; do this.
  42 ;;
  43 ;; Note that directory tracking is done by matching regular expressions,
  44 ;; therefore it is *VERY IMPORTANT* for your prompt to be easily
  45 ;; distinguishable from other output.  If your prompt regexp is too general,
  46 ;; you will see error messages from the dirtrack filter as it attempts to cd
  47 ;; to non-existent directories.
  48 ;;
  49 ;; 2) Set the variable `dirtrack-list' to an appropriate value.  This
  50 ;; should be a list of two elements: the first is a regular expression
  51 ;; which matches your prompt up to and including the pathname part.
  52 ;; The second is a number which tells which regular expression group to
  53 ;; match to extract only the pathname.  If you use a multi-line prompt,
  54 ;; add 't' as a third element.  Note that some of the functions in
  55 ;; 'comint.el' assume a single-line prompt (eg, comint-bol).
  56 ;;
  57 ;; Determining this information may take some experimentation.  Using
  58 ;; `dirtrack-debug-mode' may help; it causes the directory-tracking
  59 ;; filter to log messages to the buffer `dirtrack-debug-buffer'.
  60 ;;
  61 ;; 3) Activate `dirtrack-mode'.  You may wish to turn ordinary shell
  62 ;; tracking off by calling `shell-dirtrack-mode'.
  63 ;;
  64 ;; Examples:
  65 ;;
  66 ;; 1) On Windows NT, my prompt is set to emacs$S$P$G.
  67 ;; 'dirtrack-list' is set to (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
  68 ;;
  69 ;; 2) On Solaris running bash, my prompt is set like this:
  70 ;;    PS1="\w\012emacs@\h(\!) [\t]% "
  71 ;;    'dirtrack-list' is set to (list "^\\([/~].*\\)\nemacs@[^%]+% *" 1 t)
  72 ;;
  73 ;; I'd appreciate other examples from people who use this package.
  74 ;;
  75 ;; Here's one from Stephen Eglen:
  76 ;;
  77 ;;   Running under tcsh:
  78 ;;   (setq-default dirtrack-list '("^%E \\([^ ]+\\)" 1))
  79 ;;
  80 ;;   It might be worth mentioning in your file that emacs sources start up
  81 ;;   files of the form: ~/.emacs_<SHELL> where <SHELL> is the name of the
  82 ;;   shell.  So for example, I have the following in ~/.emacs_tcsh:
  83 ;;
  84 ;;   set prompt = "%%E %~ %h% "
  85 ;;
  86 ;;   This produces a prompt of the form:
  87 ;;   %E /var/spool 10%
  88 ;;
  89 ;;   This saves me from having to use the %E prefix in other non-emacs
  90 ;;   shells.
  91 ;;
  92 ;; A final note:
  93 ;;
  94 ;;   I run LOTS of shell buffers through Emacs, sometimes as different users
  95 ;;   (eg, when logged in as myself, I'll run a root shell in the same Emacs).
  96 ;;   If you do this, and the shell prompt contains a ~, Emacs will interpret
  97 ;;   this relative to the user which owns the Emacs process, not the user
  98 ;;   who owns the shell buffer.  This may cause dirtrack to behave strangely
  99 ;;   (typically it reports that it is unable to cd to a directory
 100 ;;   with a ~ in it).
 101 ;;
 102 ;;   The same behavior can occur if you use dirtrack with remote filesystems
 103 ;;   (using telnet, rlogin, etc) as Emacs will be checking the local
 104 ;;   filesystem, not the remote one.  This problem is not specific to dirtrack,
 105 ;;   but also affects file completion, etc.
 106
 107 ;;; Code:
 108
 109 (eval-when-compile
 110   (require 'comint)
 111   (require 'shell))
 112
 113 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 114 ;; Customization Variables
 115 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 116
 117 (defgroup dirtrack nil
 118   "Directory tracking by watching the prompt."
 119   :prefix "dirtrack-"
 120   :group 'shell)
 121
 122 (defcustom dirtrack-list (list "^emacs \\([a-zA-Z]:.*\\)>" 1)
 123   "List for directory tracking.
 124 First item is a regexp that describes where to find the path in a prompt.
 125 Second is a number, the regexp group to match.  Optional third item is
 126 whether the prompt is multi-line.  If nil or omitted, prompt is assumed to
 127 be on a single line."
 128   :group 'dirtrack
 129   :type  '(sexp (regexp  :tag "Prompt Expression")
 130                 (integer :tag "Regexp Group")
 131                 (boolean :tag "Multiline Prompt")))
 132
 133 (make-variable-buffer-local 'dirtrack-list)
 134
 135 (defcustom dirtrack-debug nil
 136   "If non-nil, the function `dirtrack' will report debugging info."
 137   :group 'dirtrack
 138   :type  'boolean)
 139
 140 (defcustom dirtrack-debug-buffer "*Directory Tracking Log*"
 141   "Buffer in which to write directory tracking debug information."
 142   :group 'dirtrack
 143   :type  'string)
 144
 145 (defcustom dirtrack-directory-function
 146   (if (memq system-type '(ms-dos windows-nt cygwin))
 147       'dirtrack-windows-directory-function
 148     'file-name-as-directory)
 149   "Function to apply to the prompt directory for comparison purposes."
 150   :group 'dirtrack
 151   :type  'function)
 152
 153 (defcustom dirtrack-canonicalize-function
 154   (if (memq system-type '(ms-dos windows-nt cygwin))
 155       'downcase 'identity)
 156   "Function to apply to the default directory for comparison purposes."
 157   :group 'dirtrack
 158   :type  'function)
 159
 160 (defcustom dirtrack-directory-change-hook nil
 161   "Hook that is called when a directory change is made."
 162   :group 'dirtrack
 163   :type 'hook)
 164
 165
 166 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 167 ;; Functions
 168 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 169
 170
 171 (defun dirtrack-windows-directory-function (dir)
 172   "Return a canonical directory for comparison purposes.
 173 Such a directory is all lowercase, has forward-slashes as delimiters,
 174 and ends with a forward slash."
 175   (file-name-as-directory (downcase (subst-char-in-string ?\\ ?/ dir))))
 176
 177 (defun dirtrack-cygwin-directory-function (dir)
 178   "Return a canonical directory taken from a Cygwin path for comparison purposes."
 179   (if (string-match "/cygdrive/\\([A-Z]\\)\\(.*\\)" dir)
 180       (concat (match-string 1 dir) ":" (match-string 2 dir))
 181     dir))
 182
 183
 184 ;;;###autoload
 185 (define-minor-mode dirtrack-mode
 186   "Enable or disable Dirtrack directory tracking in a shell buffer.
 187 This method requires that your shell prompt contain the full
 188 current working directory at all times, and that `dirtrack-list'
 189 is set to match the prompt.  This is an alternative to
 190 `shell-dirtrack-mode', which works differently, by tracking `cd'
 191 and similar commands which change the shell working directory."
 192   nil nil nil
 193   (if dirtrack-mode
 194       (add-hook 'comint-preoutput-filter-functions 'dirtrack nil t)
 195     (remove-hook 'comint-preoutput-filter-functions 'dirtrack t)))
 196
 197 (define-obsolete-function-alias 'dirtrack-toggle 'dirtrack-mode "23.1")
 198 (define-obsolete-variable-alias 'dirtrackp 'dirtrack-mode "23.1")
 199
 200
 201 (define-minor-mode dirtrack-debug-mode
 202   "Enable or disable Dirtrack debugging."
 203   nil nil nil
 204   (if dirtrack-debug-mode
 205       (display-buffer (get-buffer-create dirtrack-debug-buffer))))
 206
 207 (define-obsolete-function-alias 'dirtrack-debug-toggle 'dirtrack-debug-mode
 208   "23.1")
 209 (define-obsolete-variable-alias 'dirtrack-debug 'dirtrack-debug-mode "23.1")
 210
 211
 212 (defun dirtrack-debug-message (string)
 213   "Insert string at the end of `dirtrack-debug-buffer'."
 214   (when dirtrack-debug-mode
 215     (with-current-buffer (get-buffer-create dirtrack-debug-buffer)
 216       (goto-char (point-max))
 217       (insert (concat string "\n")))))
 218
 219 ;;;###autoload
 220 (defun dirtrack (input)
 221   "Determine the current directory by scanning the process output for a prompt.
 222 The prompt to look for is the first item in `dirtrack-list'.
 223
 224 You can toggle directory tracking by using the function `dirtrack-mode'.
 225
 226 If directory tracking does not seem to be working, you can use the
 227 function `dirtrack-debug-mode' to turn on debugging output."
 228   (unless (or (null dirtrack-mode)
 229               (eq (point) (point-min)))     ; no output?
 230     (let (prompt-path
 231           (current-dir default-directory)
 232           (dirtrack-regexp    (nth 0 dirtrack-list))
 233           (match-num          (nth 1 dirtrack-list)))
 234           ;; Currently unimplemented, it seems.  --Stef
 235           ;; (multi-line      (nth 2 dirtrack-list)))
 236       (save-excursion
 237         ;; No match
 238         (if (not (string-match dirtrack-regexp input))
 239             (dirtrack-debug-message
 240              (format "Input `%s' failed to match `dirtrack-list'" input))
 241           (setq prompt-path (match-string match-num input))
 242           ;; Empty string
 243           (if (not (> (length prompt-path) 0))
 244               (dirtrack-debug-message "Match is empty string")
 245             ;; Transform prompts into canonical forms
 246             (setq prompt-path (funcall dirtrack-directory-function
 247                                        prompt-path)
 248                   current-dir (funcall dirtrack-canonicalize-function
 249                                        current-dir))
 250             (dirtrack-debug-message
 251              (format "Prompt is %s\nCurrent directory is %s"
 252                      prompt-path current-dir))
 253             ;; Compare them
 254             (if (or (string= current-dir prompt-path)
 255                     (string= current-dir (abbreviate-file-name prompt-path)))
 256                 (dirtrack-debug-message (format "Not changing directory"))
 257               ;; It's possible that Emacs will think the directory
 258               ;; won't exist (eg, rlogin buffers)
 259               (if (file-accessible-directory-p prompt-path)
 260                   ;; Change directory
 261                   (and (shell-process-cd prompt-path)
 262                        (run-hooks 'dirtrack-directory-change-hook)
 263                        (dirtrack-debug-message
 264                         (format "Changing directory to %s" prompt-path)))
 265                 (warn "Directory %s does not exist" prompt-path)))
 266             )))))
 267   input)
 268
 269 (provide 'dirtrack)
 270
 271 ;;; dirtrack.el ends here