lisp/rfn-eshadow.el

   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, 2008, 2009 Free Software Foundation, Inc.
   5 ;;
   6 ;; Author: Miles Bader <miles@gnu.org>
   7 ;; Keywords: convenience minibuffer
   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 ;; Defines the mode `file-name-shadow-mode'.
  27 ;;
  28 ;; The `read-file-name' function passes its result through
  29 ;; `substitute-in-file-name', so any part of the string preceding
  30 ;; multiple slashes (or a drive indicator on MS-DOS/MS-Windows) is
  31 ;; ignored.
  32 ;;
  33 ;; If `file-name-shadow-mode' is active, any part of the
  34 ;; minibuffer text that would be ignored because of this is given the
  35 ;; properties in `file-name-shadow-properties', which may
  36 ;; be used to make the ignored text invisible, dim, etc.
  37 ;;
  38
  39 ;;; Code:
  40
  41 \f
  42 ;;; Customization
  43
  44 (defconst file-name-shadow-properties-custom-type
  45   '(list
  46     (checklist :inline t
  47                (const :tag "Invisible"
  48                       :doc "Make shadowed part of filename invisible"
  49                       :format "%t%n%h"
  50                       :inline t
  51                       (invisible t intangible t))
  52                (list :inline t
  53                      :format "%v"
  54                      :tag "Face"
  55                      :doc "Display shadowed part of filename using a different face"
  56                      (const :format "" face)
  57                      (face :value file-name-shadow))
  58                (list :inline t
  59                      :format "%t: %v%h"
  60                      :tag "Brackets"
  61                      ;; Note the 4 leading spaces in the doc string;
  62                      ;; this is hack to get around the fact that the
  63                      ;; newline after the second string widget comes
  64                      ;; from the string widget, and doesn't indent
  65                      ;; correctly.  We could use a :size attribute to
  66                      ;; make the second string widget not have a
  67                      ;; terminating newline, but this makes it impossible
  68                      ;; to enter trailing whitespace, and it's desirable
  69                      ;; that it be possible.
  70                      :doc "    Surround shadowed part of filename with brackets"
  71                      (const :format "" before-string)
  72                      (string :format "%v" :size 4 :value "{")
  73                      (const :format "" after-string)
  74                      ;; see above about why the 2nd string doesn't use :size
  75                      (string :format " and: %v" :value "} "))
  76                (list :inline t
  77                      :format "%t: %v%n%h"
  78                      :tag "String"
  79                      :doc "Display a string instead of the shadowed part of filename"
  80                      (const :format "" display)
  81                      (string :format "%v" :size 15 :value "<...ignored...>"))
  82                (const :tag "Avoid"
  83                       :doc "Try to keep cursor out of shadowed part of filename"
  84                       :format "%t%n%h"
  85                       :inline t
  86                       (field shadow)))
  87     (repeat :inline t
  88             :tag "Other Properties"
  89             (list :inline t
  90                   :format "%v"
  91                   (symbol :tag "Property")
  92                   (sexp :tag "Value")))))
  93
  94 (defcustom file-name-shadow-properties
  95   '(face file-name-shadow field shadow)
  96   "Properties given to the `shadowed' part of a filename in the minibuffer.
  97 Only used when `file-name-shadow-mode' is active.
  98 If Emacs is not running under a window system,
  99 `file-name-shadow-tty-properties' is used instead."
 100   :type file-name-shadow-properties-custom-type
 101   :group 'minibuffer
 102   :version "22.1")
 103
 104 (defcustom file-name-shadow-tty-properties
 105   '(before-string "{" after-string "} " field shadow)
 106   "Properties given to the `shadowed' part of a filename in the minibuffer.
 107 Only used when `file-name-shadow-mode' is active and Emacs
 108 is not running under a window-system; if Emacs is running under a window
 109 system, `file-name-shadow-properties' is used instead."
 110   :type file-name-shadow-properties-custom-type
 111   :group 'minibuffer
 112   :version "22.1")
 113
 114 (defface file-name-shadow
 115   '((t :inherit shadow))
 116   "Face used by `file-name-shadow-mode' for the shadow."
 117   :group 'minibuffer
 118   :version "22.1")
 119
 120 (defvar rfn-eshadow-setup-minibuffer-hook nil
 121   "Minibuffer setup functions from other packages.")
 122
 123 (defvar rfn-eshadow-update-overlay-hook nil
 124   "Customer overlay functions from other packages")
 125
 126 \f
 127 ;;; Internal variables
 128
 129 ;; A list of minibuffers to which we've added a post-command-hook.
 130 (defvar rfn-eshadow-frobbed-minibufs nil)
 131
 132 ;; An overlay covering the shadowed part of the filename (local to the
 133 ;; minibuffer).
 134 (defvar rfn-eshadow-overlay)
 135 (make-variable-buffer-local 'rfn-eshadow-overlay)
 136
 137 \f
 138 ;;; Hook functions
 139
 140 ;; This function goes on minibuffer-setup-hook
 141 (defun rfn-eshadow-setup-minibuffer ()
 142   "Set up a minibuffer for `file-name-shadow-mode'.
 143 The prompt and initial input should already have been inserted."
 144   (when minibuffer-completing-file-name
 145     (setq rfn-eshadow-overlay
 146           (make-overlay (minibuffer-prompt-end) (minibuffer-prompt-end)))
 147     ;; Give rfn-eshadow-overlay the user's props.
 148     (let ((props
 149            (if window-system
 150                file-name-shadow-properties
 151              file-name-shadow-tty-properties)))
 152       (while props
 153         (overlay-put rfn-eshadow-overlay (pop props) (pop props))))
 154     ;; Turn on overlay evaporation so that we don't have to worry about
 155     ;; odd effects when the overlay sits empty at the beginning of the
 156     ;; minibuffer.
 157     (overlay-put rfn-eshadow-overlay 'evaporate t)
 158     ;; Add our post-command hook, and make sure can remove it later.
 159     (add-to-list 'rfn-eshadow-frobbed-minibufs (current-buffer))
 160     (add-hook 'post-command-hook #'rfn-eshadow-update-overlay nil t)
 161     ;; Run custom hook
 162     (run-hooks 'rfn-eshadow-setup-minibuffer-hook)))
 163
 164 (defsubst rfn-eshadow-sifn-equal (goal pos)
 165   (equal goal (condition-case nil
 166                   (substitute-in-file-name
 167                    (buffer-substring-no-properties pos (point-max)))
 168                 ;; `substitute-in-file-name' can fail on partial input.
 169                 (error nil))))
 170
 171 ;; post-command-hook to update overlay
 172 (defun rfn-eshadow-update-overlay ()
 173   "Update `rfn-eshadow-overlay' to cover shadowed part of minibuffer input.
 174 This is intended to be used as a minibuffer `post-command-hook' for
 175 `file-name-shadow-mode'; the minibuffer should have already
 176 been set up by `rfn-eshadow-setup-minibuffer'."
 177   (condition-case nil
 178       (let ((goal (substitute-in-file-name (minibuffer-contents)))
 179             (mid (overlay-end rfn-eshadow-overlay))
 180             (start (minibuffer-prompt-end))
 181             (end (point-max)))
 182         (unless
 183             ;; Catch the common case where the shadow does not need to move.
 184             (and mid
 185                  (or (eq mid end)
 186                      (not (rfn-eshadow-sifn-equal goal (1+ mid))))
 187                  (or (eq mid start)
 188                      (rfn-eshadow-sifn-equal goal mid)))
 189           ;; Binary search for the greatest position still equivalent to
 190           ;; the whole.
 191           (while (or (< (1+ start) end)
 192                      (if (and (< (1+ end) (point-max))
 193                               (rfn-eshadow-sifn-equal goal (1+ end)))
 194                          ;; (SIFN end) != goal, but (SIFN (1+end)) == goal,
 195                          ;; We've reached a discontinuity: this can happen
 196                          ;; e.g. if `end' point to "/:...".
 197                          (setq start (1+ end) end (point-max))))
 198             (setq mid (/ (+ start end) 2))
 199             (if (rfn-eshadow-sifn-equal goal mid)
 200                 (setq start mid)
 201               (setq end mid)))
 202           (move-overlay rfn-eshadow-overlay (minibuffer-prompt-end) start))
 203         ;; Run custom hook
 204         (run-hooks 'rfn-eshadow-update-overlay-hook))
 205     ;; `substitute-in-file-name' can fail on partial input.
 206     (error nil)))
 207 \f
 208 (define-minor-mode file-name-shadow-mode
 209   "Toggle File-Name Shadow mode.
 210 When active, any part of a filename being read in the minibuffer
 211 that would be ignored (because the result is passed through
 212 `substitute-in-file-name') is given the properties in
 213 `file-name-shadow-properties', which can be used to make
 214 that portion dim, invisible, or otherwise less visually noticeable.
 215
 216 With prefix argument ARG, turn on if positive, otherwise off.
 217 Returns non-nil if the new state is enabled."
 218   :global t
 219   :init-value t
 220   :group 'minibuffer
 221   :version "22.1"
 222   (if file-name-shadow-mode
 223       ;; Enable the mode
 224       (add-hook 'minibuffer-setup-hook 'rfn-eshadow-setup-minibuffer)
 225     ;; Disable the mode
 226     (remove-hook 'minibuffer-setup-hook 'rfn-eshadow-setup-minibuffer)
 227     ;; Remove our entry from any post-command-hook variable's it's still in
 228     (dolist (minibuf rfn-eshadow-frobbed-minibufs)
 229       (with-current-buffer minibuf
 230         (remove-hook 'post-command-hook #'rfn-eshadow-update-overlay t)))
 231     (setq rfn-eshadow-frobbed-minibufs nil)))
 232
 233
 234 (provide 'rfn-eshadow)
 235
 236 ;; arch-tag: dcf70a52-0115-4ec2-b1e3-4f8d3541a888
 237 ;;; rfn-eshadow.el ends here