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