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