lisp/view.el

   1 ;;; view.el --- peruse file or buffer without editing
   2
   3 ;; Copyright (C) 1985, 1989, 1994, 1995, 1997, 2000, 2001, 2002,
   4 ;;   2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   5
   6 ;; Author: K. Shane Hartman
   7 ;; Maintainer: Inge Frick <inge@nada.kth.se>
   8 ;; Keywords: files
   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 3 of the License, or
  15 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This package provides the `view' minor mode documented in the Emacs
  28 ;; user's manual.
  29 ;; View mode entry and exit is done through the functions view-mode-enter
  30 ;; and view-mode-exit.  Use these functions to enter or exit view-mode from
  31 ;; emacs lisp programs.
  32 ;; We use both view- and View- as prefix for symbols.  View- is used as
  33 ;; prefix for commands that have a key binding.  view- is used for commands
  34 ;; without key binding.  The purpose of this is to make it easier for a
  35 ;; user to use command name completion.
  36
  37 ;;; Suggested key bindings:
  38 ;;
  39 ;; (define-key ctl-x-4-map "v" 'view-file-other-window)  ; ^x4v
  40 ;; (define-key ctl-x-5-map "v" 'view-file-other-frame)  ; ^x5v
  41 ;;
  42 ;; You could also bind view-file, view-buffer, view-buffer-other-window and
  43 ;; view-buffer-other-frame to keys.
  44 \f
  45 ;;; Code:
  46
  47 (defgroup view nil
  48   "Peruse file or buffer without editing."
  49   :link '(function-link view-mode)
  50   :link '(custom-manual "(emacs)Misc File Ops")
  51   :group 'wp
  52   :group 'editing)
  53
  54 (defcustom view-highlight-face 'highlight
  55    "The face used for highlighting the match found by View mode search."
  56    :type 'face
  57    :group 'view)
  58
  59 ;; `view-mode-auto-exit' is replaced by the following option variable which
  60 ;; only says if scrolling past buffer end should leave view mode or not, it
  61 ;; doesn't say if leaving view mode should restore windows or not.  The latter
  62 ;; is now controlled by the presence of a value in `view-return-to-alist'.
  63 (defcustom view-scroll-auto-exit nil
  64   "Non-nil means scrolling past the end of buffer exits View mode.
  65 A value of nil means attempting to scroll past the end of the buffer,
  66 only rings the bell and gives a message on how to leave."
  67   :type 'boolean
  68   :group 'view)
  69
  70 (defcustom view-try-extend-at-buffer-end nil
  71  "Non-nil means try to load more of file when reaching end of buffer.
  72 This variable is mainly intended to be temporarily set to non-nil by
  73 the F command in view-mode, but you can set it to t if you want the action
  74 for all scroll commands in view mode."
  75   :type 'boolean
  76   :group 'view)
  77
  78 ;;;###autoload
  79 (defcustom view-remove-frame-by-deleting t
  80   "Determine how View mode removes a frame no longer needed.
  81 If nil, make an icon of the frame.  If non-nil, delete the frame."
  82   :type 'boolean
  83   :group 'view
  84   ;; Changed the default of this to t for Emacs 23.  Users consider
  85   ;; frame iconification annoying.
  86   :version "23.1")
  87
  88 (defcustom view-exits-all-viewing-windows nil
  89   "Non-nil means restore all windows used to view buffer.
  90 Commands that restore windows when finished viewing a buffer, apply to all
  91 windows that display the buffer and have restore information in
  92 `view-return-to-alist'.
  93 If `view-exits-all-viewing-windows' is nil, only the selected window is
  94 considered for restoring."
  95   :type 'boolean
  96   :group 'view)
  97
  98 (defcustom view-inhibit-help-message nil
  99   "Non-nil inhibits the help message shown upon entering View mode."
 100   :type 'boolean
 101   :group 'view
 102   :version "22.1")
 103
 104 ;;;###autoload
 105 (defvar view-mode nil
 106   "Non-nil if View mode is enabled.
 107 Don't change this variable directly, you must change it by one of the
 108 functions that enable or disable view mode.")
 109 ;;;###autoload
 110 (make-variable-buffer-local 'view-mode)
 111
 112 (defcustom view-mode-hook nil
 113   "Normal hook run when starting to view a buffer or file."
 114   :type 'hook
 115   :group 'view)
 116 \f
 117 (defvar view-old-buffer-read-only nil)
 118 (make-variable-buffer-local 'view-old-buffer-read-only)
 119
 120 (defvar view-old-Helper-return-blurb)
 121 (make-variable-buffer-local 'view-old-Helper-return-blurb)
 122
 123 (defvar view-page-size nil
 124   "Default number of lines to scroll by View page commands.
 125 If nil that means use the window size.")
 126 (make-variable-buffer-local 'view-page-size)
 127
 128 (defvar view-half-page-size nil
 129   "Default number of lines to scroll by View half page commands.
 130 If nil that means use half the window size.")
 131 (make-variable-buffer-local 'view-half-page-size)
 132
 133 (defvar view-last-regexp nil)
 134 (make-variable-buffer-local 'view-last-regexp) ; Global is better???
 135
 136 (defvar view-return-to-alist nil
 137   "What to do with used windows and where to go when finished viewing buffer.
 138 This is local in each buffer being viewed.
 139 It is added to by `view-mode-enter' when starting to view a buffer and
 140 subtracted from by `view-mode-exit' when finished viewing the buffer.
 141
 142 See RETURN-TO-ALIST argument of function `view-mode-exit' for the format of
 143 `view-return-to-alist'.")
 144 (make-variable-buffer-local 'view-return-to-alist)
 145 (put 'view-return-to-alist 'permanent-local t)
 146
 147 (defvar view-exit-action nil
 148   "If non-nil, a function with one argument (a buffer) called when finished viewing.
 149 Commands like \\[view-file] and \\[view-file-other-window] may
 150 set this to bury or kill the viewed buffer.
 151 Observe that the buffer viewed might not appear in any window at
 152 the time this function is called.")
 153 (make-variable-buffer-local 'view-exit-action)
 154
 155 (defvar view-no-disable-on-exit nil
 156   "If non-nil, View mode \"exit\" commands don't actually disable View mode.
 157 Instead, these commands just switch buffers or windows.
 158 This is set in certain buffers by specialized features such as help commands
 159 that use View mode automatically.")
 160
 161 (defvar view-overlay nil
 162   "Overlay used to display where a search operation found its match.
 163 This is local in each buffer, once it is used.")
 164 (make-variable-buffer-local 'view-overlay)
 165
 166 (unless (assq 'view-mode minor-mode-alist)
 167   (setq minor-mode-alist
 168         (cons (list 'view-mode
 169                     (propertize " View"
 170                                 'local-map mode-line-minor-mode-keymap
 171                                 'help-echo "mouse-3: minor mode menu"))
 172               minor-mode-alist)))
 173 \f
 174 ;; Define keymap inside defvar to make it easier to load changes.
 175 ;; Some redundant "less"-like key bindings below have been commented out.
 176 (defvar view-mode-map
 177   (let ((map (make-sparse-keymap)))
 178     (define-key map "C" 'View-kill-and-leave)
 179     (define-key map "c" 'View-leave)
 180     (define-key map "Q" 'View-quit-all)
 181     (define-key map "E" 'View-exit-and-edit)
 182     ;; (define-key map "v" 'View-exit)
 183     (define-key map "e" 'View-exit)
 184     (define-key map "q" 'View-quit)
 185     ;; (define-key map "N" 'View-search-last-regexp-backward)
 186     (define-key map "p" 'View-search-last-regexp-backward)
 187     (define-key map "n" 'View-search-last-regexp-forward)
 188     ;; (define-key map "?" 'View-search-regexp-backward) ; Less does this.
 189     (define-key map "\\" 'View-search-regexp-backward)
 190     (define-key map "/" 'View-search-regexp-forward)
 191     (define-key map "r" 'isearch-backward)
 192     (define-key map "s" 'isearch-forward)
 193     (define-key map "m" 'point-to-register)
 194     (define-key map "'" 'register-to-point)
 195     (define-key map "x" 'exchange-point-and-mark)
 196     (define-key map "@" 'View-back-to-mark)
 197     (define-key map "." 'set-mark-command)
 198     (define-key map "%" 'View-goto-percent)
 199     ;; (define-key map "G" 'View-goto-line-last)
 200     (define-key map "g" 'View-goto-line)
 201     (define-key map "=" 'what-line)
 202     (define-key map "F" 'View-revert-buffer-scroll-page-forward)
 203     ;; (define-key map "k" 'View-scroll-line-backward)
 204     (define-key map "y" 'View-scroll-line-backward)
 205     ;; (define-key map "j" 'View-scroll-line-forward)
 206     (define-key map "\n" 'View-scroll-line-forward)
 207     (define-key map "\r" 'View-scroll-line-forward)
 208     (define-key map "u" 'View-scroll-half-page-backward)
 209     (define-key map "d" 'View-scroll-half-page-forward)
 210     (define-key map "z" 'View-scroll-page-forward-set-page-size)
 211     (define-key map "w" 'View-scroll-page-backward-set-page-size)
 212     ;; (define-key map "b" 'View-scroll-page-backward)
 213     (define-key map "\C-?" 'View-scroll-page-backward)
 214     ;; (define-key map "f" 'View-scroll-page-forward)
 215     (define-key map " " 'View-scroll-page-forward)
 216     (define-key map "o" 'View-scroll-to-buffer-end)
 217     (define-key map ">" 'end-of-buffer)
 218     (define-key map "<" 'beginning-of-buffer)
 219     (define-key map "-" 'negative-argument)
 220     (define-key map "9" 'digit-argument)
 221     (define-key map "8" 'digit-argument)
 222     (define-key map "7" 'digit-argument)
 223     (define-key map "6" 'digit-argument)
 224     (define-key map "5" 'digit-argument)
 225     (define-key map "4" 'digit-argument)
 226     (define-key map "3" 'digit-argument)
 227     (define-key map "2" 'digit-argument)
 228     (define-key map "1" 'digit-argument)
 229     (define-key map "0" 'digit-argument)
 230     (define-key map "H" 'describe-mode)
 231     (define-key map "?" 'describe-mode) ; Maybe do as less instead? See above.
 232     (define-key map "h" 'describe-mode)
 233     map))
 234
 235 (or (assq 'view-mode minor-mode-map-alist)
 236     (setq minor-mode-map-alist
 237           (cons (cons 'view-mode view-mode-map) minor-mode-map-alist)))
 238 \f
 239 ;;; Commands that enter or exit view mode.
 240
 241 ;; This is used when view mode is exited, to make sure we don't try to
 242 ;; kill a buffer modified by the user.  A buffer in view mode can
 243 ;; become modified if the user types C-x C-q, edits the buffer, then
 244 ;; types C-x C-q again to return to view mode.
 245 ;;;###autoload
 246 (defun kill-buffer-if-not-modified (buf)
 247   "Like `kill-buffer', but does nothing if the buffer is modified."
 248   (let ((buf (get-buffer buf)))
 249     (and buf (not (buffer-modified-p buf))
 250          (kill-buffer buf))))
 251
 252 ;;;###autoload
 253 (defun view-file (file)
 254   "View FILE in View mode, returning to previous buffer when done.
 255 Emacs commands editing the buffer contents are not available; instead, a
 256 special set of commands (mostly letters and punctuation) are defined for
 257 moving around in the buffer.
 258 Space scrolls forward, Delete scrolls backward.
 259 For a list of all View commands, type H or h while viewing.
 260
 261 This command runs the normal hook `view-mode-hook'."
 262   (interactive "fView file: ")
 263   (unless (file-exists-p file) (error "%s does not exist" file))
 264   (let ((had-a-buf (get-file-buffer file))
 265         (buffer (find-file-noselect file)))
 266     (if (eq (with-current-buffer buffer
 267               (get major-mode 'mode-class))
 268             'special)
 269         (progn
 270           (switch-to-buffer buffer)
 271           (message "Not using View mode because the major mode is special"))
 272       (view-buffer buffer (and (not had-a-buf) 'kill-buffer-if-not-modified)))))
 273
 274 ;;;###autoload
 275 (defun view-file-other-window (file)
 276   "View FILE in View mode in another window.
 277 When done, return that window to its previous buffer, and kill the
 278 buffer visiting FILE if unmodified and if it wasn't visited before.
 279
 280 Emacs commands editing the buffer contents are not available; instead,
 281 a special set of commands (mostly letters and punctuation)
 282 are defined for moving around in the buffer.
 283 Space scrolls forward, Delete scrolls backward.
 284 For a list of all View commands, type H or h while viewing.
 285
 286 This command runs the normal hook `view-mode-hook'."
 287   (interactive "fIn other window view file: ")
 288   (unless (file-exists-p file) (error "%s does not exist" file))
 289   (let ((had-a-buf (get-file-buffer file))
 290         (buf-to-view (find-file-noselect file)))
 291     (view-buffer-other-window buf-to-view nil
 292                               (and (not had-a-buf)
 293                                    'kill-buffer-if-not-modified))))
 294
 295 ;;;###autoload
 296 (defun view-file-other-frame (file)
 297   "View FILE in View mode in another frame.
 298 When done, kill the buffer visiting FILE if unmodified and if it wasn't
 299 visited before; also, maybe delete other frame and/or return to previous
 300 buffer.
 301
 302 Emacs commands editing the buffer contents are not available; instead,
 303 a special set of commands (mostly letters and punctuation)
 304 are defined for moving around in the buffer.
 305 Space scrolls forward, Delete scrolls backward.
 306 For a list of all View commands, type H or h while viewing.
 307
 308 This command runs the normal hook `view-mode-hook'."
 309   (interactive "fIn other frame view file: ")
 310   (unless (file-exists-p file) (error "%s does not exist" file))
 311   (let ((had-a-buf (get-file-buffer file))
 312         (buf-to-view (find-file-noselect file)))
 313     (view-buffer-other-frame buf-to-view nil
 314                              (and (not had-a-buf)
 315                                   'kill-buffer-if-not-modified))))
 316
 317
 318 ;;;###autoload
 319 (defun view-buffer (buffer &optional exit-action)
 320   "View BUFFER in View mode, returning to previous buffer when done.
 321 Emacs commands editing the buffer contents are not available; instead, a
 322 special set of commands (mostly letters and punctuation) are defined for
 323 moving around in the buffer.
 324 Space scrolls forward, Delete scrolls backward.
 325 For a list of all View commands, type H or h while viewing.
 326
 327 This command runs the normal hook `view-mode-hook'.
 328
 329 Optional argument EXIT-ACTION is either nil or a function with buffer as
 330 argument.  This function is called when finished viewing buffer.  Use
 331 this argument instead of explicitly setting `view-exit-action'.
 332
 333 Do not set EXIT-ACTION to `kill-buffer' when BUFFER visits a
 334 file: Users may suspend viewing in order to modify the buffer.
 335 Exiting View mode will then discard the user's edits.  Setting
 336 EXIT-ACTION to `kill-buffer-if-not-modified' avoids this."
 337   (interactive "bView buffer: ")
 338   (let ((undo-window (list (window-buffer) (window-start) (window-point))))
 339     (switch-to-buffer buffer)
 340     (view-mode-enter (cons (selected-window) (cons nil undo-window))
 341                      exit-action)))
 342
 343 ;;;###autoload
 344 (defun view-buffer-other-window (buffer &optional not-return exit-action)
 345   "View BUFFER in View mode in another window.
 346 Return to previous buffer when done, unless optional NOT-RETURN is
 347 non-nil.  Emacs commands editing the buffer contents are not available;
 348 instead, a special set of commands (mostly letters and punctuation) are
 349 defined for moving around in the buffer.
 350 Space scrolls forward, Delete scrolls backward.
 351 For a list of all View commands, type H or h while viewing.
 352
 353 This command runs the normal hook `view-mode-hook'.
 354
 355 Optional argument EXIT-ACTION is either nil or a function with buffer as
 356 argument.  This function is called when finished viewing buffer.  Use
 357 this argument instead of explicitly setting `view-exit-action'."
 358   (interactive "bIn other window view buffer:\nP")
 359   (let* ((win                           ; This window will be selected by
 360           (get-lru-window))             ; switch-to-buffer-other-window below.
 361          (return-to
 362           (and (not not-return)
 363                (cons (selected-window)
 364                      (if (eq win (selected-window))
 365                          t                      ; Has to make new window.
 366                        (list
 367                         (window-buffer win)     ; Other windows old buffer.
 368                         (window-start win)
 369                         (window-point win)))))))
 370     (switch-to-buffer-other-window buffer)
 371     (view-mode-enter (and return-to (cons (selected-window) return-to))
 372                      exit-action)))
 373
 374 ;;;###autoload
 375 (defun view-buffer-other-frame (buffer &optional not-return exit-action)
 376   "View BUFFER in View mode in another frame.
 377 Return to previous buffer when done, unless optional NOT-RETURN is
 378 non-nil.  Emacs commands editing the buffer contents are not available;
 379 instead, a special set of commands (mostly letters and punctuation) are
 380 defined for moving around in the buffer.
 381 Space scrolls forward, Delete scrolls backward.
 382 For a list of all View commands, type H or h while viewing.
 383
 384 This command runs the normal hook `view-mode-hook'.
 385
 386 Optional argument EXIT-ACTION is either nil or a function with buffer as
 387 argument.  This function is called when finished viewing buffer.  Use
 388 this argument instead of explicitly setting `view-exit-action'."
 389   (interactive "bView buffer in other frame: \nP")
 390   (let ((return-to
 391          (and (not not-return) (cons (selected-window) t)))) ; Old window.
 392     (switch-to-buffer-other-frame buffer)
 393     (view-mode-enter (and return-to (cons (selected-window) return-to))
 394                      exit-action)))
 395 \f
 396 ;;;###autoload
 397 (defun view-mode (&optional arg)
 398   ;; In the following documentation string we have to use some explicit key
 399   ;; bindings instead of using the \\[] construction.  The reason for this
 400   ;; is that most commands have more than one key binding.
 401   "Toggle View mode, a minor mode for viewing text but not editing it.
 402 With prefix argument ARG, turn View mode on if ARG is positive, otherwise
 403 turn it off.
 404
 405 Emacs commands that do not change the buffer contents are available as usual.
 406 Kill commands insert text in kill buffers but do not delete.  Other commands
 407 \(among them most letters and punctuation) beep and tell that the buffer is
 408 read-only.
 409 \\<view-mode-map>
 410 The following additional commands are provided.  Most commands take prefix
 411 arguments.  Page commands default to \"page size\" lines which is almost a whole
 412 window full, or number of lines set by \\[View-scroll-page-forward-set-page-size] or \\[View-scroll-page-backward-set-page-size].  Half page commands default to
 413 and set \"half page size\" lines which initially is half a window full.  Search
 414 commands default to a repeat count of one.
 415
 416 H, h, ?  This message.
 417 Digits  provide prefix arguments.
 418 \\[negative-argument]   negative prefix argument.
 419 \\[beginning-of-buffer] move to the beginning of buffer.
 420 >       move to the end of buffer.
 421 \\[View-scroll-to-buffer-end]   scroll so that buffer end is at last line of window.
 422 SPC     scroll forward \"page size\" lines.
 423           With prefix scroll forward prefix lines.
 424 DEL     scroll backward \"page size\" lines.
 425           With prefix scroll backward prefix lines.
 426 \\[View-scroll-page-forward-set-page-size]      like  \\[View-scroll-page-forward]  but with prefix sets \"page size\" to prefix.
 427 \\[View-scroll-page-backward-set-page-size]     like  \\[View-scroll-page-backward]  but with prefix sets \"page size\" to prefix.
 428 \\[View-scroll-half-page-forward]       scroll forward \"half page size\" lines.  With prefix, sets
 429           \"half page size\" to prefix lines and scrolls forward that much.
 430 \\[View-scroll-half-page-backward]      scroll backward \"half page size\" lines.  With prefix, sets
 431           \"half page size\" to prefix lines and scrolls backward that much.
 432 RET, LFD  scroll forward one line.  With prefix scroll forward prefix line(s).
 433 y       scroll backward one line.  With prefix scroll backward prefix line(s).
 434 \\[View-revert-buffer-scroll-page-forward]      revert-buffer if necessary and scroll forward.
 435           Use this to view a changing file.
 436 \\[what-line]   prints the current line number.
 437 \\[View-goto-percent]   goes prefix argument (default 100) percent into buffer.
 438 \\[View-goto-line]      goes to line given by prefix argument (default first line).
 439 .       set the mark.
 440 x       exchanges point and mark.
 441 \\[View-back-to-mark]   return to mark and pops mark ring.
 442           Mark ring is pushed at start of every successful search and when
 443           jump to line occurs.  The mark is set on jump to buffer start or end.
 444 \\[point-to-register]   save current position in character register.
 445 '       go to position saved in character register.
 446 s       do forward incremental search.
 447 r       do reverse incremental search.
 448 \\[View-search-regexp-forward]  searches forward for regular expression, starting after current page.
 449           ! and @ have a special meaning at the beginning of the regexp.
 450           ! means search for a line with no match for regexp.  @ means start
 451           search at beginning (end for backward search) of buffer.
 452 \\      searches backward for regular expression, starting before current page.
 453 \\[View-search-last-regexp-forward]     searches forward for last regular expression.
 454 p       searches backward for last regular expression.
 455 \\[View-quit]   quit View mode, restoring this window and buffer to previous state.
 456           \\[View-quit] is the normal way to leave view mode.
 457 \\[View-exit]   exit View mode but stay in current buffer.  Use this if you started
 458           viewing a buffer (file) and find out you want to edit it.
 459           This command restores the previous read-only status of the buffer.
 460 \\[View-exit-and-edit]  exit View mode, and make the current buffer editable
 461           even if it was not editable before entry to View mode.
 462 \\[View-quit-all]       quit View mode, restoring all windows to previous state.
 463 \\[View-leave]  quit View mode and maybe switch buffers, but don't kill this buffer.
 464 \\[View-kill-and-leave] quit View mode, kill current buffer and go back to other buffer.
 465
 466 The effect of \\[View-leave], \\[View-quit] and \\[View-kill-and-leave] depends on how view-mode was entered.  If it was
 467 entered by view-file, view-file-other-window, view-file-other-frame, or
 468 \\[dired-view-file] \(\\[view-file], \\[view-file-other-window],
 469 \\[view-file-other-frame], or the Dired mode v command),
 470 then \\[View-quit] will try to kill the current buffer.
 471 If view-mode was entered from another buffer, by \\[view-buffer],
 472 \\[view-buffer-other-window], \\[view-buffer-other frame], \\[view-file],
 473 \\[view-file-other-window], or \\[view-file-other-frame],
 474 then \\[View-leave], \\[View-quit] and \\[View-kill-and-leave] will return to that buffer.
 475
 476 Entry to view-mode runs the normal hook `view-mode-hook'."
 477   (interactive "P")
 478   (unless (and arg                      ; Do nothing if already OK.
 479                (if (> (prefix-numeric-value arg) 0) view-mode (not view-mode)))
 480     (if view-mode (view-mode-disable)
 481       (view-mode-enable))))
 482 \f
 483 (defun view-mode-enable ()
 484   "Turn on View mode."
 485   ;; Always leave view mode before changing major mode.
 486   ;; This is to guarantee that the buffer-read-only variable is restored.
 487   (add-hook 'change-major-mode-hook 'view-mode-disable nil t)
 488   (setq view-mode t
 489         view-page-size nil
 490         view-half-page-size nil
 491         view-old-buffer-read-only buffer-read-only
 492         buffer-read-only t)
 493   (if (boundp 'Helper-return-blurb)
 494       (setq view-old-Helper-return-blurb (and (boundp 'Helper-return-blurb)
 495                                               Helper-return-blurb)
 496             Helper-return-blurb
 497             (format "continue viewing %s"
 498                     (if (buffer-file-name)
 499                         (file-name-nondirectory (buffer-file-name))
 500                       (buffer-name)))))
 501   (force-mode-line-update)
 502   (run-hooks 'view-mode-hook))
 503
 504 (defun view-mode-disable ()
 505   "Turn off View mode."
 506   (remove-hook 'change-major-mode-hook 'view-mode-disable t)
 507   (and view-overlay (delete-overlay view-overlay))
 508   (force-mode-line-update)
 509   ;; Calling toggle-read-only while View mode is enabled
 510   ;; sets view-read-only to t as a buffer-local variable
 511   ;; after exiting View mode.  That arranges that the next toggle-read-only
 512   ;; will reenable View mode.
 513   ;; Cancelling View mode in any other way should cancel that, too,
 514   ;; so that View mode stays off if toggle-read-only is called.
 515   (if (local-variable-p 'view-read-only)
 516       (kill-local-variable 'view-read-only))
 517   (setq view-mode nil)
 518   (if (boundp 'Helper-return-blurb)
 519       (setq Helper-return-blurb view-old-Helper-return-blurb))
 520   (if buffer-read-only
 521       (setq buffer-read-only view-old-buffer-read-only)))
 522
 523 ;;;###autoload
 524 (defun view-return-to-alist-update (buffer &optional item)
 525   "Update `view-return-to-alist' of buffer BUFFER.
 526 Remove from `view-return-to-alist' all entries referencing dead
 527 windows.  Optional argument ITEM non-nil means add ITEM to
 528 `view-return-to-alist' after purging.  For a decsription of items
 529 that can be added see the RETURN-TO-ALIST argument of the
 530 function `view-mode-exit'.  If `view-return-to-alist' contains an
 531 entry for the selected window, purge that entry from
 532 `view-return-to-alist' before adding ITEM."
 533   (with-current-buffer buffer
 534     (when view-return-to-alist
 535       (let* ((list view-return-to-alist)
 536              entry entry-window last)
 537         (while list
 538           (setq entry (car list))
 539           (setq entry-window (car entry))
 540           (if (and (windowp entry-window)
 541                    (or (and item (eq entry-window (selected-window)))
 542                        (not (window-live-p entry-window))))
 543               ;; Remove that entry.
 544               (if last
 545                   (setcdr last (cdr list))
 546                 (setq view-return-to-alist
 547                       (cdr view-return-to-alist)))
 548             ;; Leave entry alone.
 549             (setq last entry))
 550           (setq list (cdr list)))))
 551     ;; Add ITEM.
 552     (when item
 553       (setq view-return-to-alist
 554             (cons item view-return-to-alist)))))
 555
 556 ;;;###autoload
 557 (defun view-mode-enter (&optional return-to exit-action)
 558   "Enter View mode and set up exit from view mode depending on optional arguments.
 559 RETURN-TO non-nil means add RETURN-TO as an element to the buffer
 560 local alist `view-return-to-alist'.  Save EXIT-ACTION in buffer
 561 local variable `view-exit-action'.  It should be either nil or a
 562 function that takes a buffer as argument.  This function will be
 563 called by `view-mode-exit'.
 564
 565 RETURN-TO is either nil, meaning do nothing when exiting view
 566 mode, or must have the format (WINDOW OLD-WINDOW . OLD-BUF-INFO).
 567 WINDOW is the window used for viewing.  OLD-WINDOW is nil or the
 568 window to select after viewing.  OLD-BUF-INFO tells what to do
 569 with WINDOW when exiting.  It is one of:
 570 1) nil            Do nothing.
 571 2) t              Delete WINDOW or, if it is the only window and
 572                   `view-remove-frame-by-deleting' is non-nil, its
 573                   frame.
 574 3) (OLD-BUFF START POINT)  Display buffer OLD-BUFF with displayed text
 575                   starting at START and point at POINT in WINDOW.
 576 4) quit-window    Do `quit-window' in WINDOW.
 577 5) keep-frame     Like case 2) but do not delete the frame.
 578
 579 For a list of all View commands, type H or h while viewing.
 580
 581 This function runs the normal hook `view-mode-hook'."
 582   (when return-to
 583     (let ((entry (assq (car return-to) view-return-to-alist)))
 584       (if entry
 585           (setcdr entry (cdr return-to))
 586         (setq view-return-to-alist (cons return-to view-return-to-alist)))))
 587   (when exit-action
 588     (setq view-exit-action exit-action))
 589
 590   (unless view-mode
 591     (view-mode-enable)
 592     (force-mode-line-update)
 593     (unless view-inhibit-help-message
 594       (message "%s"
 595                (substitute-command-keys "\
 596 View mode: type \\[help-command] for help, \\[describe-mode] for commands, \\[View-quit] to quit.")))))
 597 \f
 598 (defun view-mode-exit (&optional return-to-alist exit-action all-win)
 599   "Exit View mode in various ways, depending on optional arguments.
 600 RETURN-TO-ALIST, EXIT-ACTION and ALL-WIN determine what to do
 601 after exit.  EXIT-ACTION is nil or a function that is called with
 602 current buffer as argument.
 603
 604 RETURN-TO-ALIST is an alist that, for some of the windows
 605 displaying the current buffer, maintains information on what to
 606 do when exiting those windows.  If ALL-WIN is non-nil or the
 607 variable `view-exits-all-viewing-windows' is non-nil,
 608 view-mode-exit attempts to restore all windows showing the
 609 current buffer to their old state.  Otherwise, only the selected
 610 window is affected (provided it is on RETURN-TO-ALIST).
 611
 612 Elements of RETURN-TO-ALIST must have the format
 613   (WINDOW OLD-WINDOW . OLD-BUF-INFO) where
 614
 615 WINDOW is a window displaying the current buffer and OLD-WINDOW
 616 is either nil or a window to select after viewing.  OLD-BUF-INFO
 617 provides information on what to do with WINDOW and may be one of:
 618 1) nil            Do nothing.
 619 2) t              Delete WINDOW and, if it is the only window and
 620                   `view-remove-frame-by-deleting' is non-nil, its
 621                   frame.
 622 3) (OLD-BUF START POINT)  Display buffer OLD-BUF with displayed text
 623                   starting at START and point at POINT in WINDOW.
 624 4) quit-window    Do `quit-window' in WINDOW.
 625 5) keep-frame     Like case 2) but do not delete the frame.
 626
 627 If one of the WINDOW in RETURN-TO-ALIST is the selected window
 628 and the corresponding OLD-WINDOW is a live window, then select
 629 OLD-WINDOW."
 630   (when view-mode                   ; Only do something if in view mode.
 631     (setq all-win
 632           (and return-to-alist
 633                (or all-win view-exits-all-viewing-windows)))
 634     (let* ((buffer (current-buffer))
 635            window notlost
 636            (sel-old (assq (selected-window) return-to-alist))
 637            (alist (cond
 638                    (all-win                ; Try to restore all windows.
 639                     (append return-to-alist nil)) ; Copy.
 640                    (sel-old                     ; Only selected window.
 641                     (list sel-old))))
 642            (old-window (if sel-old (car (cdr sel-old)))))
 643       (if all-win                        ; Follow chains of old-windows.
 644           (let ((c (length alist)) a)
 645             (while (and (> c 0)   ; Safety if mutually refering windows.
 646                         (or (not (window-live-p old-window))
 647                             (eq buffer (window-buffer old-window)))
 648                         (setq a (assq old-window alist)))
 649               (setq c (1- c))
 650               (setq old-window (car (cdr a))))
 651             (if (or (zerop c) (not (window-live-p old-window)))
 652                 (setq old-window (selected-window)))))
 653       (unless view-no-disable-on-exit
 654         (view-mode-disable))
 655       (while alist                          ; Restore windows with info.
 656         (setq notlost nil)
 657         (when (and (window-live-p (setq window (car (car alist))))
 658                    (eq buffer (window-buffer window)))
 659           (let ((frame (window-frame window))
 660                 (old-buf-info (cdr (cdr (car alist)))))
 661             (if all-win (select-window window))
 662             (cond
 663              ((consp old-buf-info)              ; Case 3.
 664               (if (buffer-live-p (car old-buf-info))
 665                   (progn
 666                     (set-window-buffer window (car old-buf-info)) ; old-buf
 667                     (set-window-start window (car (cdr old-buf-info)))
 668                     (set-window-point window (car (cdr (cdr old-buf-info)))))
 669                 (bury-buffer)))
 670              ((eq old-buf-info 'quit-window)
 671               (quit-window))                    ; Case 4.
 672              (old-buf-info                      ; Case 2 or 5.
 673               (cond
 674                ((not (one-window-p t))          ; Not only window.
 675                 (delete-window))
 676                ((eq old-buf-info 'keep-frame)   ; Case 5.
 677                 (bury-buffer))
 678                ((not (eq frame (next-frame)))  ; Case 2 and only window.
 679                 ;; Not the only frame, so can safely be removed.
 680                 (if view-remove-frame-by-deleting
 681                     (delete-frame frame)
 682                   (setq notlost t)         ; Keep the window.  See below.
 683                   (iconify-frame frame))))))))
 684         ;; If a frame is removed by iconifying it, the window is not
 685         ;; really lost.  In this case we keep the entry in
 686         ;; `view-return-to-alist' so that if the user deiconifies the
 687         ;; frame and then hits q, the frame is iconified again.
 688         (unless notlost
 689           (with-current-buffer buffer
 690             (setq view-return-to-alist
 691                   (delete (car alist) view-return-to-alist))))
 692         (setq alist (cdr alist)))
 693       (when (window-live-p old-window)
 694         ;; old-window is still alive => select it.
 695         (select-window old-window))
 696       (when exit-action
 697         ;; Don't do that: If the user wants to quit the *Help* buffer a
 698         ;; second time it won't have any effect.
 699         ;;(setq view-exit-action nil)
 700         (funcall exit-action buffer))
 701       (force-mode-line-update))))
 702 \f
 703 (defun View-exit ()
 704   "Exit View mode but stay in current buffer."
 705   (interactive)
 706   (view-mode-exit))
 707
 708 ;;;###autoload
 709 (defun View-exit-and-edit ()
 710   "Exit View mode and make the current buffer editable."
 711   (interactive)
 712   (let ((view-old-buffer-read-only nil)
 713         (view-no-disable-on-exit nil))
 714     (view-mode-exit)))
 715
 716 (defun View-leave ()
 717   "Quit View mode and maybe switch buffers, but don't kill this buffer."
 718   (interactive)
 719   (view-mode-exit view-return-to-alist))
 720
 721 (defun View-quit ()
 722   "Quit View mode, trying to restore window and buffer to previous state.
 723 Maybe kill this buffer.  Try to restore selected window to previous state
 724 and go to previous buffer or window."
 725   (interactive)
 726   (view-mode-exit view-return-to-alist view-exit-action))
 727
 728 (defun View-quit-all ()
 729   "Quit View mode, trying to restore windows and buffers to previous state.
 730 Maybe kill current buffer.  Try to restore all windows viewing buffer to
 731 previous state and go to previous buffer or window."
 732   (interactive)
 733   (view-mode-exit view-return-to-alist view-exit-action t))
 734
 735 (defun View-kill-and-leave ()
 736   "Quit View mode, kill current buffer and return to previous buffer."
 737   (interactive)
 738   (view-mode-exit view-return-to-alist (or view-exit-action 'kill-buffer) t))
 739 \f
 740
 741 ;;; Some help routines.
 742
 743 (defun view-window-size ()
 744   ;; Return the height of the current window, excluding the mode line.
 745   ;; Using `window-line-height' accounts for variable-height fonts.
 746   (let ((h (window-line-height -1)))
 747     (if h
 748         (1+ (nth 1 h))
 749       ;; This should not happen, but if `window-line-height' returns
 750       ;; nil, fall back on `window-height'.
 751       (1- (window-height)))))
 752
 753 ;; (defun view-last-command (&optional who what)
 754 ;;  (setq view-last-command-entry this-command)
 755 ;;  (setq view-last-command who)
 756 ;;  (setq view-last-command-argument what))
 757
 758 ;; (defun View-repeat-last-command ()
 759 ;;  "Repeat last command issued in View mode."
 760 ;;  (interactive)
 761 ;;  (if (and view-last-command
 762 ;;         (eq view-last-command-entry last-command))
 763 ;;      (funcall view-last-command view-last-command-argument))
 764 ;;  (setq this-command view-last-command-entry))
 765
 766 (defun view-recenter ()
 767   ;; Recenter point in window and redisplay normally.
 768   (recenter '(1)))
 769
 770 (defun view-page-size-default (lines)
 771   ;; If LINES is nil, 0, or larger than `view-window-size', return nil.
 772   ;; Otherwise, return LINES.
 773   (and lines
 774        (not (zerop (setq lines (prefix-numeric-value lines))))
 775        (<= (abs lines)
 776            (abs (- (view-window-size) next-screen-context-lines)))
 777        (abs lines)))
 778
 779 (defun view-set-half-page-size-default (lines)
 780   ;; Get and maybe set half page size.
 781   (if (not lines) (or view-half-page-size
 782                       (/ (view-window-size) 2))
 783     (setq view-half-page-size
 784           (if (zerop (setq lines (prefix-numeric-value lines)))
 785               (/ (view-window-size) 2)
 786             (view-page-size-default lines)))))
 787
 788
 789 ;;; Commands for moving around in the buffer.
 790
 791 (defun View-goto-percent (&optional percent)
 792   "Move to end (or prefix PERCENT) of buffer in View mode.
 793 Display is centered at point.
 794 Also set the mark at the position where point was."
 795   (interactive "P")
 796   (push-mark)
 797   (goto-char
 798    (if percent
 799        (+ (point-min)
 800           (floor (* (- (point-max) (point-min)) 0.01
 801                     (max 0 (min 100 (prefix-numeric-value percent))))))
 802      (point-max)))
 803   (view-recenter))
 804
 805 ;; (defun View-goto-line-last (&optional line)
 806 ;; "Move to last (or prefix LINE) line in View mode.
 807 ;; Display is centered at LINE.
 808 ;; Sets mark at starting position and pushes mark ring."
 809 ;;  (interactive "P")
 810 ;;  (push-mark)
 811 ;;  (if line (goto-line (prefix-numeric-value line))
 812 ;;    (goto-char (point-max))
 813 ;;    (beginning-of-line))
 814 ;;  (view-recenter))
 815
 816 (defun View-goto-line (&optional line)
 817   "Move to first (or prefix LINE) line in View mode.
 818 Display is centered at LINE.
 819 Also set the mark at the position where point was."
 820   (interactive "p")
 821   (push-mark)
 822   (goto-char (point-min))
 823   (forward-line (1- line))
 824   (view-recenter))
 825
 826 (defun View-back-to-mark (&optional ignore)
 827   "Return to last mark set in View mode, else beginning of file.
 828 Display that line at the center of the window.
 829 This command pops the mark ring, so that successive
 830 invocations return to earlier marks."
 831   (interactive)
 832   (goto-char (or (mark t) (point-min)))
 833   (pop-mark)
 834   (view-recenter))
 835 \f
 836 (defun view-scroll-lines (lines backward default maxdefault)
 837   ;; This function does the job for all the scrolling commands.
 838   ;; Scroll forward LINES lines.  If BACKWARD is non-nil, scroll backwards.
 839   ;; If LINES is negative scroll in the other direction.
 840   ;; If LINES is 0 or nil, scroll DEFAULT lines (if DEFAULT is nil, scroll
 841   ;; by one page).  If MAXDEFAULT is non-nil, scroll no more than a window.
 842   (if (or (null lines) (zerop (setq lines (prefix-numeric-value lines))))
 843       (setq lines default))
 844   (when (and lines (< lines 0))
 845     (setq backward (not backward) lines (- lines)))
 846   (when (and maxdefault lines (> lines (view-window-size)))
 847     (setq lines nil))
 848   (cond (backward (scroll-down lines))
 849         ((view-really-at-end)
 850          (if view-scroll-auto-exit
 851              (View-quit)
 852            (ding)
 853            (view-end-message)))
 854         (t (scroll-up lines)
 855            (if (view-really-at-end) (view-end-message)))))
 856
 857 (defun view-really-at-end ()
 858   ;; Return true if buffer end visible.  Maybe revert buffer and test.
 859   (and (pos-visible-in-window-p (point-max))
 860        (let ((buf (current-buffer))
 861              (bufname (buffer-name))
 862              (file (buffer-file-name)))
 863          (or (not view-try-extend-at-buffer-end)
 864              (null file)
 865              (verify-visited-file-modtime buf)
 866              (not (file-exists-p file))
 867              (when (buffer-modified-p buf)
 868                (setq file (file-name-nondirectory file))
 869                (not (yes-or-no-p
 870                      (format
 871                       "File %s changed on disk.  Discard your edits%s? "
 872                       file
 873                       (if (string= bufname file) ""
 874                         (concat " in " bufname))))))
 875              (progn
 876                (revert-buffer t t t)
 877                (pos-visible-in-window-p (point-max)))))))
 878
 879 (defun view-end-message ()
 880   ;; Tell that we are at end of buffer.
 881   (goto-char (point-max))
 882   (if view-return-to-alist
 883       (message "End of buffer.  Type %s to quit viewing."
 884                (substitute-command-keys
 885                 (if view-scroll-auto-exit "\\[View-scroll-page-forward]"
 886                   "\\[View-quit]")))
 887     (message "End of buffer")))
 888 \f
 889 (defun View-scroll-to-buffer-end ()
 890   "Scroll backward or forward so that buffer end is at last line of window."
 891   (interactive)
 892   (let ((p (if (pos-visible-in-window-p (point-max)) (point))))
 893     (goto-char (point-max))
 894     (recenter -1)
 895     (and p (goto-char p))))
 896
 897 (defun View-scroll-page-forward (&optional lines)
 898   "Scroll \"page size\" or prefix LINES lines forward in View mode.
 899 Exit if end of text is visible and `view-scroll-auto-exit' is non-nil.
 900 \"page size\" is whole window full, or number of lines set by
 901 \\[View-scroll-page-forward-set-page-size] or
 902 \\[View-scroll-page-backward-set-page-size].
 903 If LINES is more than a window-full, only the last window-full is shown."
 904   (interactive "P")
 905   (view-scroll-lines lines nil (view-page-size-default view-page-size) nil))
 906
 907 (defun View-scroll-page-backward (&optional lines)
 908   "Scroll \"page size\" or prefix LINES lines backward in View mode.
 909 See also `View-scroll-page-forward'."
 910   (interactive "P")
 911   (view-scroll-lines lines t (view-page-size-default view-page-size) nil))
 912
 913 (defun View-scroll-page-forward-set-page-size (&optional lines)
 914   "Scroll forward LINES lines in View mode, setting the \"page size\".
 915 This is the number of lines which \\[View-scroll-page-forward] and
 916 \\[View-scroll-page-backward] scroll by default.
 917 If LINES is omitted or = 0, sets \"page size\" to window height and
 918 scrolls forward that much, otherwise scrolls forward LINES lines and sets
 919 \"page size\" to the minimum of window height and the absolute value of LINES.
 920 See also `View-scroll-page-forward'."
 921   (interactive "P")
 922   (view-scroll-lines lines nil
 923                      (setq view-page-size (view-page-size-default lines))
 924                      nil))
 925
 926 (defun View-scroll-page-backward-set-page-size (&optional lines)
 927   "Scroll backward prefix LINES lines in View mode, setting the \"page size\".
 928 See also `View-scroll-page-forward-set-page-size'."
 929   (interactive "P")
 930   (view-scroll-lines lines t
 931                      (setq view-page-size (view-page-size-default lines))
 932                      nil))
 933
 934 (defun View-scroll-line-forward (&optional lines)
 935   "Scroll forward one line (or prefix LINES lines) in View mode.
 936 See also `View-scroll-page-forward', but note that scrolling is limited
 937 to minimum of LINES and one window-full."
 938   (interactive "P")
 939   (view-scroll-lines lines nil 1 t))
 940
 941 (defun View-scroll-line-backward (&optional lines)
 942   "Scroll backward one line (or prefix LINES lines) in View mode.
 943 See also `View-scroll-line-forward'."
 944   (interactive "P")
 945   (view-scroll-lines lines t 1 t))
 946
 947 (defun View-scroll-half-page-forward (&optional lines)
 948   "Scroll forward a \"half page\" (or prefix LINES) lines in View mode.
 949 If LINES is not omitted, the \"half page size\" is set to the minimum of
 950 window height and the absolute value of LINES.
 951 LINES=0 resets \"half page size\" to half window height."
 952   (interactive "P")
 953   (view-scroll-lines lines nil (view-set-half-page-size-default lines) t))
 954
 955 (defun View-scroll-half-page-backward (&optional lines)
 956   "Scroll backward a \"half page\" (or prefix LINES) lines in View mode.
 957 See also `View-scroll-half-page-forward'."
 958   (interactive "P")
 959   (view-scroll-lines lines t (view-set-half-page-size-default lines) t))
 960
 961 (defun View-revert-buffer-scroll-page-forward (&optional lines)
 962   "Scroll forward, reverting buffer if needed, in View mode.
 963 If buffer has not been changed and the corresponding file is newer, first
 964 revert the buffer, then scroll.
 965 This command is useful if you are viewing a changing file.
 966
 967 The prefix argument LINES says how many lines to scroll.
 968 If you don't specify a prefix argument, it uses the number of lines set by
 969 \\[View-scroll-page-forward-set-page-size] or
 970 \\[View-scroll-page-backward-set-page-size].
 971 If LINES is more than a window-full, only the last window-full is shown."
 972   (interactive "P")
 973   (let ((view-scroll-auto-exit nil)
 974         (view-try-extend-at-buffer-end t))
 975     (view-scroll-lines lines nil (view-page-size-default view-page-size) nil)))
 976 \f
 977 (defun View-search-regexp-forward (n regexp)
 978   "Search forward for first (or prefix Nth) occurrence of REGEXP in View mode.
 979
 980 Displays line found at center of window.  Sets mark at starting position and
 981 pushes mark ring.
 982
 983 Characters @ and ! are special at the beginning of REGEXP.  They modify
 984 the search rather than become part of the pattern searched for.
 985 @ means search all the buffer i.e. start search at the beginning of buffer.
 986 ! means search for a line that contains no match for the pattern.
 987 If REGEXP is empty or only consist of these control characters, then
 988 an earlier remembered REGEXP is used, otherwise REGEXP is remembered
 989 for use by later search commands.
 990
 991 The variable `view-highlight-face' controls the face that is used
 992 for highlighting the match that is found."
 993   (interactive "p\nsSearch forward (regexp): ")
 994   (view-search n regexp))
 995
 996 (defun View-search-regexp-backward (n regexp)
 997   "Search backward for first (or prefix Nth) occurrence of REGEXP in View mode.
 998
 999 Displays line found at center of window.  Sets mark at starting position and
1000 pushes mark ring.
1001
1002 Characters @ and ! are special at the beginning of REGEXP.  They modify
1003 the search rather than become part of the pattern searched for.
1004 @ means search all the buffer i.e. start search at the end of buffer.
1005 ! means search for a line that contains no match for the pattern.
1006 If REGEXP is empty or only consist of these control characters, then
1007 an earlier remembered REGEXP is used, otherwise REGEXP is remembered
1008 for use by later search commands.
1009
1010 The variable `view-highlight-face' controls the face that is used
1011 for highlighting the match that is found."
1012   (interactive "p\nsSearch backward (regexp): ")
1013   (view-search (- n) regexp))
1014
1015 (defun View-search-last-regexp-forward (n) "\
1016 Search forward for first (or prefix Nth) instance of last regexp in View mode.
1017 Displays line found at center of window.  Sets mark at starting position and
1018 pushes mark ring.
1019
1020 The variable `view-highlight-face' controls the face that is used
1021 for highlighting the match that is found."
1022   (interactive "p")
1023   (view-search n nil))
1024
1025 (defun View-search-last-regexp-backward (n) "\
1026 Search backward for first (or prefix Nth) instance of last regexp in View mode.
1027 Displays line found at center of window.  Sets mark at starting position and
1028 pushes mark ring.
1029
1030 The variable `view-highlight-face' controls the face that is used
1031 for highlighting the match that is found."
1032   (interactive "p")
1033   (view-search (- n) nil))
1034
1035 (defun view-search (times regexp)
1036   ;; This function does the job for all the View-search- commands.
1037   ;; Search for the TIMESt match for REGEXP.  If TIMES is negative
1038   ;; search backwards.  If REGEXP is nil use `view-last-regexp'.
1039   ;; Characters "!" and "@" have a special meaning at the beginning of
1040   ;; REGEXP and are removed from REGEXP before the search "!" means
1041   ;; search for lines with no match for REGEXP.  "@" means search in
1042   ;; the whole buffer, don't start searching from the present point.
1043   (let (where no end ln)
1044     (cond
1045      ((and regexp (> (length regexp) 0)
1046            (or (not (memq (string-to-char regexp) '(?! ?@)))
1047                (progn
1048                  (if (member (substring regexp 0 2) '("!@" "@!"))
1049                      (setq end t no t ln 2)
1050                    (setq no (not (setq end (eq ?@ (string-to-char regexp))))
1051                          ln 1))
1052                  (> (length (setq regexp (substring regexp ln))) 0))))
1053       (setq view-last-regexp (if no (list regexp) regexp)))
1054      ((consp view-last-regexp)
1055       (setq regexp (car view-last-regexp))
1056       (unless (setq no (not no)) (setq view-last-regexp regexp)))
1057      (view-last-regexp (setq regexp view-last-regexp)
1058                        (if no (setq view-last-regexp (list regexp))))
1059      (t (error "No previous View-mode search")))
1060     (save-excursion
1061       (if end (goto-char (if (< times 0) (point-max) (point-min)))
1062         (move-to-window-line (if (< times 0) 0 -1)))
1063       (if (if no (view-search-no-match-lines times regexp)
1064             (re-search-forward regexp nil t times))
1065           (setq where (point))))
1066     (if where
1067         (progn
1068           (push-mark)
1069           (goto-char where)
1070           (if view-overlay
1071               (move-overlay view-overlay (match-beginning 0) (match-end 0))
1072             (setq view-overlay
1073                   (make-overlay (match-beginning 0) (match-end 0))))
1074           (overlay-put view-overlay 'face view-highlight-face)
1075           (beginning-of-line)
1076           (view-recenter))
1077       (message "Can't find occurrence %d of %s%s"
1078                times (if no "no " "") regexp)
1079       (sit-for 4))))
1080
1081 ;; This is the dumb approach, looking at each line.  The original
1082 ;; version of this function looked like it might have been trying to
1083 ;; do something clever, but not succeeding:
1084 ;; http://lists.gnu.org/archive/html/bug-gnu-emacs/2007-09/msg00073.html
1085 (defun view-search-no-match-lines (times regexp)
1086   "Search for the TIMESth occurrence of a line with no match for REGEXP.
1087 If such a line is found, return non-nil and set the match-data to that line.
1088 If TIMES is negative, search backwards."
1089   (let ((step (if (>= times 0) 1
1090                 (setq times (- times))
1091                 -1)))
1092     ;; Note that we do not check the current line.
1093     (while (and (> times 0)
1094                 (zerop (forward-line step)))
1095       ;; (forward-line 1) returns 0 on moving within the last line.
1096       (if (eobp)
1097           (setq times -1)
1098         (or (re-search-forward regexp (line-end-position) t)
1099             (setq times (1- times))))))
1100   (and (zerop times)
1101        (looking-at ".*")))
1102
1103 (provide 'view)
1104
1105 ;; arch-tag: 6d0ace36-1d12-4de3-8de3-1fa3231636d7
1106 ;;; view.el ends here