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[emacs.git] / lisp / rfn-eshadow.el
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1 ;;; rfn-eshadow.el --- Highlight `shadowed' part of read-file-name input text
2 ;;
3 ;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
4 ;; 2005, 2006, 2007 Free Software Foundation, Inc.
5 ;;
6 ;; Author: Miles Bader <miles@gnu.org>
7 ;; Keywords: convenience minibuffer
9 ;; This file is part of GNU Emacs.
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.
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.
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., 51 Franklin Street, Fifth Floor,
24 ;; Boston, MA 02110-1301, USA.
26 ;;; Commentary:
28 ;; Defines the mode `file-name-shadow-mode'.
30 ;; The `read-file-name' function passes its result through
31 ;; `substitute-in-file-name', so any part of the string preceding
32 ;; multiple slashes (or a drive indicator on MS-DOS/MS-Windows) is
33 ;; ignored.
35 ;; If `file-name-shadow-mode' is active, any part of the
36 ;; minibuffer text that would be ignored because of this is given the
37 ;; properties in `file-name-shadow-properties', which may
38 ;; be used to make the ignored text invisible, dim, etc.
41 ;;; Code:
44 ;;; Customization
46 (defconst file-name-shadow-properties-custom-type
47 '(list
48 (checklist :inline t
49 (const :tag "Invisible"
50 :doc "Make shadowed part of filename invisible"
51 :format "%t%n%h"
52 :inline t
53 (invisible t intangible t))
54 (list :inline t
55 :format "%v"
56 :tag "Face"
57 :doc "Display shadowed part of filename using a different face"
58 (const :format "" face)
59 (face :value file-name-shadow))
60 (list :inline t
61 :format "%t: %v%h"
62 :tag "Brackets"
63 ;; Note the 4 leading spaces in the doc string;
64 ;; this is hack to get around the fact that the
65 ;; newline after the second string widget comes
66 ;; from the string widget, and doesn't indent
67 ;; correctly. We could use a :size attribute to
68 ;; make the second string widget not have a
69 ;; terminating newline, but this makes it impossible
70 ;; to enter trailing whitespace, and it's desirable
71 ;; that it be possible.
72 :doc " Surround shadowed part of filename with brackets"
73 (const :format "" before-string)
74 (string :format "%v" :size 4 :value "{")
75 (const :format "" after-string)
76 ;; see above about why the 2nd string doesn't use :size
77 (string :format " and: %v" :value "} "))
78 (list :inline t
79 :format "%t: %v%n%h"
80 :tag "String"
81 :doc "Display a string instead of the shadowed part of filename"
82 (const :format "" display)
83 (string :format "%v" :size 15 :value "<...ignored...>"))
84 (const :tag "Avoid"
85 :doc "Try to keep cursor out of shadowed part of filename"
86 :format "%t%n%h"
87 :inline t
88 (field shadow)))
89 (repeat :inline t
90 :tag "Other Properties"
91 (list :inline t
92 :format "%v"
93 (symbol :tag "Property")
94 (sexp :tag "Value")))))
96 (defcustom file-name-shadow-properties
97 '(face file-name-shadow field shadow)
98 "Properties given to the `shadowed' part of a filename in the minibuffer.
99 Only used when `file-name-shadow-mode' is active.
100 If Emacs is not running under a window system,
101 `file-name-shadow-tty-properties' is used instead."
102 :type file-name-shadow-properties-custom-type
103 :group 'minibuffer
104 :version "22.1")
106 (defcustom file-name-shadow-tty-properties
107 '(before-string "{" after-string "} " field shadow)
108 "Properties given to the `shadowed' part of a filename in the minibuffer.
109 Only used when `file-name-shadow-mode' is active and Emacs
110 is not running under a window-system; if Emacs is running under a window
111 system, `file-name-shadow-properties' is used instead."
112 :type file-name-shadow-properties-custom-type
113 :group 'minibuffer
114 :version "22.1")
116 (defface file-name-shadow
117 '((t :inherit shadow))
118 "Face used by `file-name-shadow-mode' for the shadow."
119 :group 'minibuffer
120 :version "22.1")
123 ;;; Internal variables
125 ;; A list of minibuffers to which we've added a post-command-hook.
126 (defvar rfn-eshadow-frobbed-minibufs nil)
128 ;; An overlay covering the shadowed part of the filename (local to the
129 ;; minibuffer).
130 (defvar rfn-eshadow-overlay)
131 (make-variable-buffer-local 'rfn-eshadow-overlay)
134 ;;; Hook functions
136 ;; This function goes on minibuffer-setup-hook
137 (defun rfn-eshadow-setup-minibuffer ()
138 "Set up a minibuffer for `file-name-shadow-mode'.
139 The prompt and initial input should already have been inserted."
140 (when minibuffer-completing-file-name
141 (setq rfn-eshadow-overlay
142 (make-overlay (minibuffer-prompt-end) (minibuffer-prompt-end)))
143 ;; Give rfn-eshadow-overlay the user's props.
144 (let ((props
145 (if window-system
146 file-name-shadow-properties
147 file-name-shadow-tty-properties)))
148 (while props
149 (overlay-put rfn-eshadow-overlay (pop props) (pop props))))
150 ;; Turn on overlay evaporation so that we don't have to worry about
151 ;; odd effects when the overlay sits empty at the beginning of the
152 ;; minibuffer.
153 (overlay-put rfn-eshadow-overlay 'evaporate t)
154 ;; Add our post-command hook, and make sure can remove it later.
155 (add-to-list 'rfn-eshadow-frobbed-minibufs (current-buffer))
156 (add-hook 'post-command-hook #'rfn-eshadow-update-overlay nil t)))
158 (defsubst rfn-eshadow-sifn-equal (goal pos)
159 (equal goal (condition-case nil
160 (substitute-in-file-name
161 (buffer-substring-no-properties pos (point-max)))
162 ;; `substitute-in-file-name' can fail on partial input.
163 (error nil))))
165 ;; post-command-hook to update overlay
166 (defun rfn-eshadow-update-overlay ()
167 "Update `rfn-eshadow-overlay' to cover shadowed part of minibuffer input.
168 This is intended to be used as a minibuffer `post-command-hook' for
169 `file-name-shadow-mode'; the minibuffer should have already
170 been set up by `rfn-eshadow-setup-minibuffer'."
171 (condition-case nil
172 (let ((goal (substitute-in-file-name (minibuffer-contents)))
173 (mid (overlay-end rfn-eshadow-overlay))
174 (start (minibuffer-prompt-end))
175 (end (point-max)))
176 (unless
177 ;; Catch the common case where the shadow does not need to move.
178 (and mid
179 (or (eq mid end)
180 (not (rfn-eshadow-sifn-equal goal (1+ mid))))
181 (or (eq mid start)
182 (rfn-eshadow-sifn-equal goal mid)))
183 ;; Binary search for the greatest position still equivalent to
184 ;; the whole.
185 (while (or (< (1+ start) end)
186 (if (and (< (1+ end) (point-max))
187 (rfn-eshadow-sifn-equal goal (1+ end)))
188 ;; (SIFN end) != goal, but (SIFN (1+end)) == goal,
189 ;; We've reached a discontinuity: this can happen
190 ;; e.g. if `end' point to "/:...".
191 (setq start (1+ end) end (point-max))))
192 (setq mid (/ (+ start end) 2))
193 (if (rfn-eshadow-sifn-equal goal mid)
194 (setq start mid)
195 (setq end mid)))
196 (move-overlay rfn-eshadow-overlay (minibuffer-prompt-end) start)))
197 ;; `substitute-in-file-name' can fail on partial input.
198 (error nil)))
200 (define-minor-mode file-name-shadow-mode
201 "Toggle File-Name Shadow mode.
202 When active, any part of a filename being read in the minibuffer
203 that would be ignored (because the result is passed through
204 `substitute-in-file-name') is given the properties in
205 `file-name-shadow-properties', which can be used to make
206 that portion dim, invisible, or otherwise less visually noticeable.
208 With prefix argument ARG, turn on if positive, otherwise off.
209 Returns non-nil if the new state is enabled."
210 :global t
211 :init-value t
212 :group 'minibuffer
213 :version "22.1"
214 (if file-name-shadow-mode
215 ;; Enable the mode
216 (add-hook 'minibuffer-setup-hook 'rfn-eshadow-setup-minibuffer)
217 ;; Disable the mode
218 (remove-hook 'minibuffer-setup-hook 'rfn-eshadow-setup-minibuffer)
219 ;; Remove our entry from any post-command-hook variable's it's still in
220 (dolist (minibuf rfn-eshadow-frobbed-minibufs)
221 (with-current-buffer minibuf
222 (remove-hook 'post-command-hook #'rfn-eshadow-update-overlay t)))
223 (setq rfn-eshadow-frobbed-minibufs nil)))
226 (provide 'rfn-eshadow)
228 ;; arch-tag: dcf70a52-0115-4ec2-b1e3-4f8d3541a888
229 ;;; rfn-eshadow.el ends here