lisp/desktop.el

   1 ;;; desktop.el --- save partial status of Emacs when killed
   2
   3 ;; Copyright (C) 1993-1995, 1997, 2000-2013 Free Software Foundation,
   4 ;; Inc.
   5
   6 ;; Author: Morten Welinder <terra@diku.dk>
   7 ;; Keywords: convenience
   8 ;; Favorite-brand-of-beer: None, I hate beer.
   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 ;; Save the Desktop, i.e.,
  28 ;;      - some global variables
  29 ;;      - the list of buffers with associated files.  For each buffer also
  30 ;;              - the major mode
  31 ;;              - the default directory
  32 ;;              - the point
  33 ;;              - the mark & mark-active
  34 ;;              - buffer-read-only
  35 ;;              - some local variables
  36
  37 ;; To use this, use customize to turn on desktop-save-mode or add the
  38 ;; following line somewhere in your init file:
  39 ;;
  40 ;;      (desktop-save-mode 1)
  41 ;;
  42 ;; For further usage information, look at the section
  43 ;; (info "(emacs)Saving Emacs Sessions") in the GNU Emacs Manual.
  44
  45 ;; When the desktop module is loaded, the function `desktop-kill' is
  46 ;; added to the `kill-emacs-hook'.  This function is responsible for
  47 ;; saving the desktop when Emacs is killed.  Furthermore an anonymous
  48 ;; function is added to the `after-init-hook'.  This function is
  49 ;; responsible for loading the desktop when Emacs is started.
  50
  51 ;; Special handling.
  52 ;; -----------------
  53 ;; Variables `desktop-buffer-mode-handlers' and `desktop-minor-mode-handlers'
  54 ;; are supplied to handle special major and minor modes respectively.
  55 ;; `desktop-buffer-mode-handlers' is an alist of major mode specific functions
  56 ;; to restore a desktop buffer.  Elements must have the form
  57 ;;
  58 ;;    (MAJOR-MODE . RESTORE-BUFFER-FUNCTION).
  59 ;;
  60 ;; Functions listed are called by `desktop-create-buffer' when `desktop-read'
  61 ;; evaluates the desktop file.  Buffers with a major mode not specified here,
  62 ;; are restored by the default handler `desktop-restore-file-buffer'.
  63 ;; `desktop-minor-mode-handlers' is an alist of functions to restore
  64 ;; non-standard minor modes.  Elements must have the form
  65 ;;
  66 ;;    (MINOR-MODE . RESTORE-FUNCTION).
  67 ;;
  68 ;; Functions are called by `desktop-create-buffer' to restore minor modes.
  69 ;; Minor modes not specified here, are restored by the standard minor mode
  70 ;; function.  If you write a module that defines a major or minor mode that
  71 ;; needs a special handler, then place code like
  72
  73 ;;    (defun foo-restore-desktop-buffer
  74 ;;    ...
  75 ;;    (add-to-list 'desktop-buffer-mode-handlers
  76 ;;                 '(foo-mode . foo-restore-desktop-buffer))
  77
  78 ;; or
  79
  80 ;;    (defun bar-desktop-restore
  81 ;;    ...
  82 ;;    (add-to-list 'desktop-minor-mode-handlers
  83 ;;                 '(bar-mode . bar-desktop-restore))
  84
  85 ;; in the module itself, and make sure that the mode function is
  86 ;; autoloaded.  See the docstrings of `desktop-buffer-mode-handlers' and
  87 ;; `desktop-minor-mode-handlers' for more info.
  88
  89 ;; Minor modes.
  90 ;; ------------
  91 ;; Conventional minor modes (see node "Minor Mode Conventions" in the elisp
  92 ;; manual) are handled in the following way:
  93 ;; When `desktop-save' saves the state of a buffer to the desktop file, it
  94 ;; saves as `desktop-minor-modes' the list of names of those variables in
  95 ;; `minor-mode-alist' that have a non-nil value.
  96 ;; When `desktop-create' restores the buffer, each of the symbols in
  97 ;; `desktop-minor-modes' is called as function with parameter 1.
  98 ;; The variables `desktop-minor-mode-table' and `desktop-minor-mode-handlers'
  99 ;; are used to handle non-conventional minor modes.  `desktop-save' uses
 100 ;; `desktop-minor-mode-table' to map minor mode variables to minor mode
 101 ;; functions before writing `desktop-minor-modes'.  If a minor mode has a
 102 ;; variable name that is different form its function name, an entry
 103
 104 ;;    (NAME RESTORE-FUNCTION)
 105
 106 ;; should be added to `desktop-minor-mode-table'.  If a minor mode should not
 107 ;; be restored, RESTORE-FUNCTION should be set to nil.  `desktop-create' uses
 108 ;; `desktop-minor-mode-handlers' to lookup minor modes that needs a restore
 109 ;; function different from the usual minor mode function.
 110 ;; ---------------------------------------------------------------------------
 111
 112 ;; By the way: don't use desktop.el to customize Emacs -- the file .emacs
 113 ;; in your home directory is used for that.  Saving global default values
 114 ;; for buffers is an example of misuse.
 115
 116 ;; PLEASE NOTE: The kill ring can be saved as specified by the variable
 117 ;; `desktop-globals-to-save' (by default it isn't).  This may result in saving
 118 ;; things you did not mean to keep.  Use M-x desktop-clear RET.
 119
 120 ;; Thanks to  hetrick@phys.uva.nl (Jim Hetrick)      for useful ideas.
 121 ;;            avk@rtsg.mot.com (Andrew V. Klein)     for a dired tip.
 122 ;;            chris@tecc.co.uk (Chris Boucher)       for a mark tip.
 123 ;;            f89-kam@nada.kth.se (Klas Mellbourn)   for a mh-e tip.
 124 ;;            kifer@sbkifer.cs.sunysb.edu (M. Kifer) for a bug hunt.
 125 ;;            treese@lcs.mit.edu (Win Treese)        for ange-ftp tips.
 126 ;;            pot@cnuce.cnr.it (Francesco Potorti`)  for misc. tips.
 127 ;; ---------------------------------------------------------------------------
 128 ;; TODO:
 129 ;;
 130 ;; Save window configuration.
 131 ;; Recognize more minor modes.
 132 ;; Save mark rings.
 133
 134 ;;; Code:
 135
 136 (defvar desktop-file-version "206"
 137   "Version number of desktop file format.
 138 Written into the desktop file and used at desktop read to provide
 139 backward compatibility.")
 140
 141 ;; ----------------------------------------------------------------------------
 142 ;; USER OPTIONS -- settings you might want to play with.
 143 ;; ----------------------------------------------------------------------------
 144
 145 (defgroup desktop nil
 146   "Save status of Emacs when you exit."
 147   :group 'frames)
 148
 149 ;; Maintained for backward compatibility
 150 (define-obsolete-variable-alias 'desktop-enable 'desktop-save-mode "22.1")
 151 ;;;###autoload
 152 (define-minor-mode desktop-save-mode
 153   "Toggle desktop saving (Desktop Save mode).
 154 With a prefix argument ARG, enable Desktop Save mode if ARG is
 155 positive, and disable it otherwise.  If called from Lisp, enable
 156 the mode if ARG is omitted or nil.
 157
 158 If Desktop Save mode is enabled, the state of Emacs is saved from
 159 one session to another.  See variable `desktop-save' and function
 160 `desktop-read' for details."
 161   :global t
 162   :group 'desktop)
 163
 164 (defun desktop-save-mode-off ()
 165   "Disable `desktop-save-mode'.  Provided for use in hooks."
 166   (desktop-save-mode 0))
 167
 168 (defcustom desktop-save 'ask-if-new
 169   "Specifies whether the desktop should be saved when it is killed.
 170 A desktop is killed when the user changes desktop or quits Emacs.
 171 Possible values are:
 172    t             -- always save.
 173    ask           -- always ask.
 174    ask-if-new    -- ask if no desktop file exists, otherwise just save.
 175    ask-if-exists -- ask if desktop file exists, otherwise don't save.
 176    if-exists     -- save if desktop file exists, otherwise don't save.
 177    nil           -- never save.
 178 The desktop is never saved when `desktop-save-mode' is nil.
 179 The variables `desktop-dirname' and `desktop-base-file-name'
 180 determine where the desktop is saved."
 181   :type
 182   '(choice
 183     (const :tag "Always save" t)
 184     (const :tag "Always ask" ask)
 185     (const :tag "Ask if desktop file is new, else do save" ask-if-new)
 186     (const :tag "Ask if desktop file exists, else don't save" ask-if-exists)
 187     (const :tag "Save if desktop file exists, else don't" if-exists)
 188     (const :tag "Never save" nil))
 189   :group 'desktop
 190   :version "22.1")
 191
 192 (defcustom desktop-auto-save-timeout nil
 193   "Number of seconds between auto-saves of the desktop.
 194 Zero or nil means disable timer-based auto-saving."
 195   :type '(choice (const :tag "Off" nil)
 196                  (integer :tag "Seconds"))
 197   :set (lambda (symbol value)
 198          (set-default symbol value)
 199          (condition-case nil
 200              (desktop-auto-save-set-timer)
 201            (error nil)))
 202   :group 'desktop
 203   :version "24.4")
 204
 205 (defcustom desktop-load-locked-desktop 'ask
 206   "Specifies whether the desktop should be loaded if locked.
 207 Possible values are:
 208    t    -- load anyway.
 209    nil  -- don't load.
 210    ask  -- ask the user.
 211 If the value is nil, or `ask' and the user chooses not to load the desktop,
 212 the normal hook `desktop-not-loaded-hook' is run."
 213   :type
 214   '(choice
 215     (const :tag "Load anyway" t)
 216     (const :tag "Don't load" nil)
 217     (const :tag "Ask the user" ask))
 218   :group 'desktop
 219   :version "22.2")
 220
 221 (define-obsolete-variable-alias 'desktop-basefilename
 222                                 'desktop-base-file-name "22.1")
 223
 224 (defcustom desktop-base-file-name
 225   (convert-standard-filename ".emacs.desktop")
 226   "Name of file for Emacs desktop, excluding the directory part."
 227   :type 'file
 228   :group 'desktop)
 229
 230 (defcustom desktop-base-lock-name
 231   (convert-standard-filename ".emacs.desktop.lock")
 232   "Name of lock file for Emacs desktop, excluding the directory part."
 233   :type 'file
 234   :group 'desktop
 235   :version "22.2")
 236
 237 (defcustom desktop-path (list user-emacs-directory "~")
 238   "List of directories to search for the desktop file.
 239 The base name of the file is specified in `desktop-base-file-name'."
 240   :type '(repeat directory)
 241   :group 'desktop
 242   :version "23.2")                      ; user-emacs-directory added
 243
 244 (defcustom desktop-missing-file-warning nil
 245   "If non-nil, offer to recreate the buffer of a deleted file.
 246 Also pause for a moment to display message about errors signaled in
 247 `desktop-buffer-mode-handlers'.
 248
 249 If nil, just print error messages in the message buffer."
 250   :type 'boolean
 251   :group 'desktop
 252   :version "22.1")
 253
 254 (defcustom desktop-no-desktop-file-hook nil
 255   "Normal hook run when `desktop-read' can't find a desktop file.
 256 Run in the directory in which the desktop file was sought.
 257 May be used to show a dired buffer."
 258   :type 'hook
 259   :group 'desktop
 260   :version "22.1")
 261
 262 (defcustom desktop-not-loaded-hook nil
 263   "Normal hook run when the user declines to re-use a desktop file.
 264 Run in the directory in which the desktop file was found.
 265 May be used to deal with accidental multiple Emacs jobs."
 266   :type 'hook
 267   :group 'desktop
 268   :options '(desktop-save-mode-off save-buffers-kill-emacs)
 269   :version "22.2")
 270
 271 (defcustom desktop-after-read-hook nil
 272   "Normal hook run after a successful `desktop-read'.
 273 May be used to show a buffer list."
 274   :type 'hook
 275   :group 'desktop
 276   :options '(list-buffers)
 277   :version "22.1")
 278
 279 (defcustom desktop-save-hook nil
 280   "Normal hook run before the desktop is saved in a desktop file.
 281 Run with the desktop buffer current with only the header present.
 282 May be used to add to the desktop code or to truncate history lists,
 283 for example."
 284   :type 'hook
 285   :group 'desktop)
 286
 287 (defcustom desktop-globals-to-save
 288   '(desktop-missing-file-warning
 289     tags-file-name
 290     tags-table-list
 291     search-ring
 292     regexp-search-ring
 293     register-alist
 294     file-name-history)
 295   "List of global variables saved by `desktop-save'.
 296 An element may be variable name (a symbol) or a cons cell of the form
 297 \(VAR . MAX-SIZE), which means to truncate VAR's value to at most
 298 MAX-SIZE elements (if the value is a list) before saving the value.
 299 Feature: Saving `kill-ring' implies saving `kill-ring-yank-pointer'."
 300   :type '(repeat (restricted-sexp :match-alternatives (symbolp consp)))
 301   :group 'desktop)
 302
 303 (defcustom desktop-globals-to-clear
 304   '(kill-ring
 305     kill-ring-yank-pointer
 306     search-ring
 307     search-ring-yank-pointer
 308     regexp-search-ring
 309     regexp-search-ring-yank-pointer)
 310   "List of global variables that `desktop-clear' will clear.
 311 An element may be variable name (a symbol) or a cons cell of the form
 312 \(VAR . FORM).  Symbols are set to nil and for cons cells VAR is set
 313 to the value obtained by evaluating FORM."
 314   :type '(repeat (restricted-sexp :match-alternatives (symbolp consp)))
 315   :group 'desktop
 316   :version "22.1")
 317
 318 (defcustom desktop-clear-preserve-buffers
 319   '("\\*scratch\\*" "\\*Messages\\*" "\\*server\\*" "\\*tramp/.+\\*"
 320     "\\*Warnings\\*")
 321   "List of buffers that `desktop-clear' should not delete.
 322 Each element is a regular expression.  Buffers with a name matched by any of
 323 these won't be deleted."
 324   :version "23.3"                       ; added Warnings - bug#6336
 325   :type '(repeat string)
 326   :group 'desktop)
 327
 328 ;;;###autoload
 329 (defcustom desktop-locals-to-save
 330   '(desktop-locals-to-save  ; Itself!  Think it over.
 331     truncate-lines
 332     case-fold-search
 333     case-replace
 334     fill-column
 335     overwrite-mode
 336     change-log-default-name
 337     line-number-mode
 338     column-number-mode
 339     size-indication-mode
 340     buffer-file-coding-system
 341     indent-tabs-mode
 342     tab-width
 343     indicate-buffer-boundaries
 344     indicate-empty-lines
 345     show-trailing-whitespace)
 346   "List of local variables to save for each buffer.
 347 The variables are saved only when they really are local.  Conventional minor
 348 modes are restored automatically; they should not be listed here."
 349   :type '(repeat symbol)
 350   :group 'desktop)
 351
 352 (defcustom desktop-buffers-not-to-save nil
 353   "Regexp identifying buffers that are to be excluded from saving."
 354   :type '(choice (const :tag "None" nil)
 355                  regexp)
 356   :version "23.2"                       ; set to nil
 357   :group 'desktop)
 358
 359 ;; Skip tramp and ange-ftp files
 360 (defcustom desktop-files-not-to-save
 361   "\\(^/[^/:]*:\\|(ftp)$\\)"
 362   "Regexp identifying files whose buffers are to be excluded from saving."
 363   :type '(choice (const :tag "None" nil)
 364                  regexp)
 365   :group 'desktop)
 366
 367 ;; We skip TAGS files to save time (tags-file-name is saved instead).
 368 (defcustom desktop-modes-not-to-save
 369   '(tags-table-mode)
 370   "List of major modes whose buffers should not be saved."
 371   :type '(repeat symbol)
 372   :group 'desktop)
 373
 374 (defcustom desktop-save-windows nil
 375   "When non-nil, save window/frame configuration to desktop file."
 376   :type 'boolean
 377   :group 'desktop
 378   :version "24.4")
 379
 380 (defcustom desktop-file-name-format 'absolute
 381   "Format in which desktop file names should be saved.
 382 Possible values are:
 383    absolute -- Absolute file name.
 384    tilde    -- Relative to ~.
 385    local    -- Relative to directory of desktop file."
 386   :type '(choice (const absolute) (const tilde) (const local))
 387   :group 'desktop
 388   :version "22.1")
 389
 390 (defcustom desktop-restore-eager t
 391   "Number of buffers to restore immediately.
 392 Remaining buffers are restored lazily (when Emacs is idle).
 393 If value is t, all buffers are restored immediately."
 394   :type '(choice (const t) integer)
 395   :group 'desktop
 396   :version "22.1")
 397
 398 (defcustom desktop-lazy-verbose t
 399   "Verbose reporting of lazily created buffers."
 400   :type 'boolean
 401   :group 'desktop
 402   :version "22.1")
 403
 404 (defcustom desktop-lazy-idle-delay 5
 405   "Idle delay before starting to create buffers.
 406 See `desktop-restore-eager'."
 407   :type 'integer
 408   :group 'desktop
 409   :version "22.1")
 410
 411 ;;;###autoload
 412 (defvar desktop-save-buffer nil
 413   "When non-nil, save buffer status in desktop file.
 414 This variable becomes buffer local when set.
 415
 416 If the value is a function, it is called by `desktop-save' with argument
 417 DESKTOP-DIRNAME to obtain auxiliary information to save in the desktop
 418 file along with the state of the buffer for which it was called.
 419
 420 When file names are returned, they should be formatted using the call
 421 \"(desktop-file-name FILE-NAME DESKTOP-DIRNAME)\".
 422
 423 Later, when `desktop-read' evaluates the desktop file, auxiliary information
 424 is passed as the argument DESKTOP-BUFFER-MISC to functions in
 425 `desktop-buffer-mode-handlers'.")
 426 (make-variable-buffer-local 'desktop-save-buffer)
 427 (make-obsolete-variable 'desktop-buffer-modes-to-save
 428                         'desktop-save-buffer "22.1")
 429 (make-obsolete-variable 'desktop-buffer-misc-functions
 430                         'desktop-save-buffer "22.1")
 431
 432 ;;;###autoload
 433 (defvar desktop-buffer-mode-handlers nil
 434   "Alist of major mode specific functions to restore a desktop buffer.
 435 Functions listed are called by `desktop-create-buffer' when `desktop-read'
 436 evaluates the desktop file.  List elements must have the form
 437
 438    (MAJOR-MODE . RESTORE-BUFFER-FUNCTION).
 439
 440 Buffers with a major mode not specified here, are restored by the default
 441 handler `desktop-restore-file-buffer'.
 442
 443 Handlers are called with argument list
 444
 445    (DESKTOP-BUFFER-FILE-NAME DESKTOP-BUFFER-NAME DESKTOP-BUFFER-MISC)
 446
 447 Furthermore, they may use the following variables:
 448
 449    desktop-file-version
 450    desktop-buffer-major-mode
 451    desktop-buffer-minor-modes
 452    desktop-buffer-point
 453    desktop-buffer-mark
 454    desktop-buffer-read-only
 455    desktop-buffer-locals
 456
 457 If a handler returns a buffer, then the saved mode settings
 458 and variable values for that buffer are copied into it.
 459
 460 Modules that define a major mode that needs a special handler should contain
 461 code like
 462
 463    (defun foo-restore-desktop-buffer
 464    ...
 465    (add-to-list 'desktop-buffer-mode-handlers
 466                 '(foo-mode . foo-restore-desktop-buffer))
 467
 468 Furthermore the major mode function must be autoloaded.")
 469
 470 ;;;###autoload
 471 (put 'desktop-buffer-mode-handlers 'risky-local-variable t)
 472 (make-obsolete-variable 'desktop-buffer-handlers
 473                         'desktop-buffer-mode-handlers "22.1")
 474
 475 (defcustom desktop-minor-mode-table
 476   '((auto-fill-function auto-fill-mode)
 477     (vc-mode nil)
 478     (vc-dired-mode nil)
 479     (erc-track-minor-mode nil)
 480     (savehist-mode nil))
 481   "Table mapping minor mode variables to minor mode functions.
 482 Each entry has the form (NAME RESTORE-FUNCTION).
 483 NAME is the name of the buffer-local variable indicating that the minor
 484 mode is active.  RESTORE-FUNCTION is the function to activate the minor mode.
 485 RESTORE-FUNCTION nil means don't try to restore the minor mode.
 486 Only minor modes for which the name of the buffer-local variable
 487 and the name of the minor mode function are different have to be added to
 488 this table.  See also `desktop-minor-mode-handlers'."
 489   :type 'sexp
 490   :group 'desktop)
 491
 492 ;;;###autoload
 493 (defvar desktop-minor-mode-handlers nil
 494   "Alist of functions to restore non-standard minor modes.
 495 Functions are called by `desktop-create-buffer' to restore minor modes.
 496 List elements must have the form
 497
 498    (MINOR-MODE . RESTORE-FUNCTION).
 499
 500 Minor modes not specified here, are restored by the standard minor mode
 501 function.
 502
 503 Handlers are called with argument list
 504
 505    (DESKTOP-BUFFER-LOCALS)
 506
 507 Furthermore, they may use the following variables:
 508
 509    desktop-file-version
 510    desktop-buffer-file-name
 511    desktop-buffer-name
 512    desktop-buffer-major-mode
 513    desktop-buffer-minor-modes
 514    desktop-buffer-point
 515    desktop-buffer-mark
 516    desktop-buffer-read-only
 517    desktop-buffer-misc
 518
 519 When a handler is called, the buffer has been created and the major mode has
 520 been set, but local variables listed in desktop-buffer-locals has not yet been
 521 created and set.
 522
 523 Modules that define a minor mode that needs a special handler should contain
 524 code like
 525
 526    (defun foo-desktop-restore
 527    ...
 528    (add-to-list 'desktop-minor-mode-handlers
 529                 '(foo-mode . foo-desktop-restore))
 530
 531 Furthermore the minor mode function must be autoloaded.
 532
 533 See also `desktop-minor-mode-table'.")
 534
 535 ;;;###autoload
 536 (put 'desktop-minor-mode-handlers 'risky-local-variable t)
 537
 538 ;; ----------------------------------------------------------------------------
 539 (defvar desktop-dirname nil
 540   "The directory in which the desktop file should be saved.")
 541
 542 (defun desktop-full-file-name (&optional dirname)
 543   "Return the full name of the desktop file in DIRNAME.
 544 DIRNAME omitted or nil means use `desktop-dirname'."
 545   (expand-file-name desktop-base-file-name (or dirname desktop-dirname)))
 546
 547 (defun desktop-full-lock-name (&optional dirname)
 548   "Return the full name of the desktop lock file in DIRNAME.
 549 DIRNAME omitted or nil means use `desktop-dirname'."
 550   (expand-file-name desktop-base-lock-name (or dirname desktop-dirname)))
 551
 552 (defconst desktop-header
 553 ";; --------------------------------------------------------------------------
 554 ;; Desktop File for Emacs
 555 ;; --------------------------------------------------------------------------
 556 " "*Header to place in Desktop file.")
 557
 558 (defvar desktop-delay-hook nil
 559   "Hooks run after all buffers are loaded; intended for internal use.")
 560
 561 (defvar desktop-file-checksum nil
 562   "Checksum of the last auto-saved contents of the desktop file.
 563 Used to avoid writing contents unchanged between auto-saves.")
 564
 565 (defvar desktop--saved-states nil
 566   "Internal use only.")
 567
 568 ;; ----------------------------------------------------------------------------
 569 ;; Desktop file conflict detection
 570 (defvar desktop-file-modtime nil
 571   "When the desktop file was last modified to the knowledge of this Emacs.
 572 Used to detect desktop file conflicts.")
 573
 574 (defun desktop-owner (&optional dirname)
 575   "Return the PID of the Emacs process that owns the desktop file in DIRNAME.
 576 Return nil if no desktop file found or no Emacs process is using it.
 577 DIRNAME omitted or nil means use `desktop-dirname'."
 578   (let (owner)
 579     (and (file-exists-p (desktop-full-lock-name dirname))
 580          (condition-case nil
 581              (with-temp-buffer
 582                (insert-file-contents-literally (desktop-full-lock-name dirname))
 583                (goto-char (point-min))
 584                (setq owner (read (current-buffer)))
 585                (integerp owner))
 586            (error nil))
 587          owner)))
 588
 589 (defun desktop-claim-lock (&optional dirname)
 590   "Record this Emacs process as the owner of the desktop file in DIRNAME.
 591 DIRNAME omitted or nil means use `desktop-dirname'."
 592   (write-region (number-to-string (emacs-pid)) nil
 593                 (desktop-full-lock-name dirname)))
 594
 595 (defun desktop-release-lock (&optional dirname)
 596   "Remove the lock file for the desktop in DIRNAME.
 597 DIRNAME omitted or nil means use `desktop-dirname'."
 598   (let ((file (desktop-full-lock-name dirname)))
 599     (when (file-exists-p file) (delete-file file))))
 600
 601 ;; ----------------------------------------------------------------------------
 602 (defun desktop-truncate (list n)
 603   "Truncate LIST to at most N elements destructively."
 604   (let ((here (nthcdr (1- n) list)))
 605     (when (consp here)
 606       (setcdr here nil))))
 607
 608 ;; ----------------------------------------------------------------------------
 609 ;;;###autoload
 610 (defun desktop-clear ()
 611   "Empty the Desktop.
 612 This kills all buffers except for internal ones and those with names matched by
 613 a regular expression in the list `desktop-clear-preserve-buffers'.
 614 Furthermore, it clears the variables listed in `desktop-globals-to-clear'."
 615   (interactive)
 616   (desktop-lazy-abort)
 617   (dolist (var desktop-globals-to-clear)
 618     (if (symbolp var)
 619         (eval `(setq-default ,var nil))
 620       (eval `(setq-default ,(car var) ,(cdr var)))))
 621   (let ((buffers (buffer-list))
 622         (preserve-regexp (concat "^\\("
 623                                  (mapconcat (lambda (regexp)
 624                                               (concat "\\(" regexp "\\)"))
 625                                             desktop-clear-preserve-buffers
 626                                             "\\|")
 627                                  "\\)$")))
 628     (while buffers
 629       (let ((bufname (buffer-name (car buffers))))
 630          (or
 631            (null bufname)
 632            (string-match preserve-regexp bufname)
 633            ;; Don't kill buffers made for internal purposes.
 634            (and (not (equal bufname "")) (eq (aref bufname 0) ?\s))
 635            (kill-buffer (car buffers))))
 636       (setq buffers (cdr buffers))))
 637   (delete-other-windows))
 638
 639 ;; ----------------------------------------------------------------------------
 640 (unless noninteractive
 641   (add-hook 'kill-emacs-hook 'desktop-kill))
 642
 643 (defun desktop-kill ()
 644   "If `desktop-save-mode' is non-nil, do what `desktop-save' says to do.
 645 If the desktop should be saved and `desktop-dirname'
 646 is nil, ask the user where to save the desktop."
 647   (when (and desktop-save-mode
 648              (let ((exists (file-exists-p (desktop-full-file-name))))
 649                (or (eq desktop-save t)
 650                    (and exists (eq desktop-save 'if-exists))
 651                    ;; If it exists, but we aren't using it, we are going
 652                    ;; to ask for a new directory below.
 653                    (and exists desktop-dirname (eq desktop-save 'ask-if-new))
 654                    (and
 655                     (or (memq desktop-save '(ask ask-if-new))
 656                         (and exists (eq desktop-save 'ask-if-exists)))
 657                     (y-or-n-p "Save desktop? ")))))
 658     (unless desktop-dirname
 659       (setq desktop-dirname
 660             (file-name-as-directory
 661              (expand-file-name
 662               (read-directory-name "Directory for desktop file: " nil nil t)))))
 663     (condition-case err
 664         (desktop-save desktop-dirname t)
 665       (file-error
 666        (unless (yes-or-no-p "Error while saving the desktop.  Ignore? ")
 667          (signal (car err) (cdr err))))))
 668   ;; If we own it, we don't anymore.
 669   (when (eq (emacs-pid) (desktop-owner)) (desktop-release-lock)))
 670
 671 ;; ----------------------------------------------------------------------------
 672 (defun desktop-list* (&rest args)
 673   (if (null (cdr args))
 674       (car args)
 675     (setq args (nreverse args))
 676     (let ((value (cons (nth 1 args) (car args))))
 677       (setq args (cdr (cdr args)))
 678       (while args
 679         (setq value (cons (car args) value))
 680         (setq args (cdr args)))
 681       value)))
 682
 683 ;; ----------------------------------------------------------------------------
 684 (defun desktop-buffer-info (buffer)
 685   (set-buffer buffer)
 686   (list
 687    ;; base name of the buffer; replaces the buffer name if managed by uniquify
 688    (and (fboundp 'uniquify-buffer-base-name) (uniquify-buffer-base-name))
 689    ;; basic information
 690    (desktop-file-name (buffer-file-name) desktop-dirname)
 691    (buffer-name)
 692    major-mode
 693    ;; minor modes
 694    (let (ret)
 695      (mapc
 696       #'(lambda (minor-mode)
 697           (and (boundp minor-mode)
 698                (symbol-value minor-mode)
 699                (let* ((special (assq minor-mode desktop-minor-mode-table))
 700                       (value (cond (special (cadr special))
 701                                    ((functionp minor-mode) minor-mode))))
 702                  (when value (add-to-list 'ret value)))))
 703       (mapcar #'car minor-mode-alist))
 704      ret)
 705    ;; point and mark, and read-only status
 706    (point)
 707    (list (mark t) mark-active)
 708    buffer-read-only
 709    ;; auxiliary information
 710    (when (functionp desktop-save-buffer)
 711      (funcall desktop-save-buffer desktop-dirname))
 712    ;; local variables
 713    (let ((locals desktop-locals-to-save)
 714          (loclist (buffer-local-variables))
 715          (ll))
 716      (while locals
 717        (let ((here (assq (car locals) loclist)))
 718          (if here
 719              (setq ll (cons here ll))
 720            (when (member (car locals) loclist)
 721              (setq ll (cons (car locals) ll)))))
 722        (setq locals (cdr locals)))
 723      ll)))
 724
 725 ;; ----------------------------------------------------------------------------
 726 (defun desktop--v2s (value)
 727   "Convert VALUE to a pair (QUOTE . SEXP); (eval SEXP) gives VALUE.
 728 SEXP is an sexp that when evaluated yields VALUE.
 729 QUOTE may be `may' (value may be quoted),
 730 `must' (value must be quoted), or nil (value must not be quoted)."
 731   (cond
 732     ((or (numberp value) (null value) (eq t value) (keywordp value))
 733      (cons 'may value))
 734     ((stringp value)
 735      (let ((copy (copy-sequence value)))
 736        (set-text-properties 0 (length copy) nil copy)
 737        ;; Get rid of text properties because we cannot read them.
 738        (cons 'may copy)))
 739     ((symbolp value)
 740      (cons 'must value))
 741     ((vectorp value)
 742      (let* ((pass1 (mapcar #'desktop--v2s value))
 743             (special (assq nil pass1)))
 744        (if special
 745            (cons nil `(vector
 746                        ,@(mapcar (lambda (el)
 747                                    (if (eq (car el) 'must)
 748                                        `',(cdr el) (cdr el)))
 749                                  pass1)))
 750          (cons 'may `[,@(mapcar #'cdr pass1)]))))
 751     ((consp value)
 752      (let ((p value)
 753            newlist
 754            use-list*
 755            anynil)
 756        (while (consp p)
 757          (let ((q.sexp (desktop--v2s (car p))))
 758            (push q.sexp newlist))
 759          (setq p (cdr p)))
 760        (when p
 761          (let ((last (desktop--v2s p)))
 762            (setq use-list* t)
 763            (push last newlist)))
 764        (if (assq nil newlist)
 765            (cons nil
 766                  `(,(if use-list* 'desktop-list* 'list)
 767                    ,@(mapcar (lambda (el)
 768                                (if (eq (car el) 'must)
 769                                    `',(cdr el) (cdr el)))
 770                              (nreverse newlist))))
 771          (cons 'must
 772                `(,@(mapcar #'cdr
 773                            (nreverse (if use-list* (cdr newlist) newlist)))
 774                  ,@(if use-list* (cdar newlist)))))))
 775     ((subrp value)
 776      (cons nil `(symbol-function
 777                  ',(intern-soft (substring (prin1-to-string value) 7 -1)))))
 778     ((markerp value)
 779      (let ((pos (marker-position value))
 780            (buf (buffer-name (marker-buffer value))))
 781        (cons nil
 782              `(let ((mk (make-marker)))
 783                 (add-hook 'desktop-delay-hook
 784                           `(lambda ()
 785                              (set-marker ,mk ,,pos (get-buffer ,,buf))))
 786                 mk))))
 787     (t                                  ; Save as text.
 788      (cons 'may "Unprintable entity"))))
 789
 790 ;; ----------------------------------------------------------------------------
 791 (defun desktop-value-to-string (value)
 792   "Convert VALUE to a string that when read evaluates to the same value.
 793 Not all types of values are supported."
 794   (let* ((print-escape-newlines t)
 795          (float-output-format nil)
 796          (quote.sexp (desktop--v2s value))
 797          (quote (car quote.sexp))
 798          (txt
 799           (let ((print-quoted t))
 800             (prin1-to-string (cdr quote.sexp)))))
 801     (if (eq quote 'must)
 802         (concat "'" txt)
 803       txt)))
 804
 805 ;; ----------------------------------------------------------------------------
 806 (defun desktop-outvar (varspec)
 807   "Output a setq statement for variable VAR to the desktop file.
 808 The argument VARSPEC may be the variable name VAR (a symbol),
 809 or a cons cell of the form (VAR . MAX-SIZE),
 810 which means to truncate VAR's value to at most MAX-SIZE elements
 811 \(if the value is a list) before saving the value."
 812   (let (var size)
 813     (if (consp varspec)
 814         (setq var (car varspec) size (cdr varspec))
 815       (setq var varspec))
 816     (when (boundp var)
 817       (when (and (integerp size)
 818                  (> size 0)
 819                  (listp (eval var)))
 820         (desktop-truncate (eval var) size))
 821       (insert "(setq "
 822               (symbol-name var)
 823               " "
 824               (desktop-value-to-string (symbol-value var))
 825               ")\n"))))
 826
 827 ;; ----------------------------------------------------------------------------
 828 (defun desktop-save-buffer-p (filename bufname mode &rest _dummy)
 829   "Return t if buffer should have its state saved in the desktop file.
 830 FILENAME is the visited file name, BUFNAME is the buffer name, and
 831 MODE is the major mode.
 832 \n\(fn FILENAME BUFNAME MODE)"
 833   (let ((case-fold-search nil)
 834         dired-skip)
 835     (and (not (and (stringp desktop-buffers-not-to-save)
 836                    (not filename)
 837                    (string-match desktop-buffers-not-to-save bufname)))
 838          (not (memq mode desktop-modes-not-to-save))
 839          ;; FIXME this is broken if desktop-files-not-to-save is nil.
 840          (or (and filename
 841                   (stringp desktop-files-not-to-save)
 842                   (not (string-match desktop-files-not-to-save filename)))
 843              (and (memq mode '(dired-mode vc-dir-mode))
 844                   (with-current-buffer bufname
 845                     (not (setq dired-skip
 846                                (string-match desktop-files-not-to-save
 847                                              default-directory)))))
 848              (and (null filename)
 849                   (null dired-skip)     ; bug#5755
 850                   (with-current-buffer bufname desktop-save-buffer))))))
 851
 852 ;; ----------------------------------------------------------------------------
 853 (defun desktop-file-name (filename dirname)
 854   "Convert FILENAME to format specified in `desktop-file-name-format'.
 855 DIRNAME must be the directory in which the desktop file will be saved."
 856   (cond
 857     ((not filename) nil)
 858     ((eq desktop-file-name-format 'tilde)
 859      (let ((relative-name (file-relative-name (expand-file-name filename) "~")))
 860        (cond
 861          ((file-name-absolute-p relative-name) relative-name)
 862          ((string= "./" relative-name) "~/")
 863          ((string= "." relative-name) "~")
 864          (t (concat "~/" relative-name)))))
 865     ((eq desktop-file-name-format 'local) (file-relative-name filename dirname))
 866     (t (expand-file-name filename))))
 867
 868
 869 ;; ----------------------------------------------------------------------------
 870 (defconst desktop--excluded-frame-parameters
 871   '(buffer-list
 872     buffer-predicate
 873     buried-buffer-list
 874     explicit-name
 875     font-backend
 876     minibuffer
 877     name
 878     outer-window-id
 879     parent-id
 880     window-id
 881     window-system)
 882   "Frame parameters not saved or restored.")
 883
 884 (defun desktop--filter-frame-parms (frame)
 885   "Return frame parameters of FRAME.
 886 Parameters in `desktop--excluded-frame-parameters' are excluded.
 887 Internal use only."
 888   (let (params)
 889     (dolist (param (frame-parameters frame))
 890       (unless (memq (car param) desktop--excluded-frame-parameters)
 891         (push param params)))
 892     params))
 893
 894 (defun desktop--save-windows ()
 895   "Save window/frame state, as a global variable.
 896 Intended to be called from `desktop-save'.
 897 Internal use only."
 898   (setq desktop--saved-states
 899         (and desktop-save-windows
 900              (mapcar (lambda (frame)
 901                        (cons (desktop--filter-frame-parms frame)
 902                              (window-state-get (frame-root-window frame) t)))
 903                      (cons (selected-frame)
 904                            (delq (selected-frame) (frame-list))))))
 905   (desktop-outvar 'desktop--saved-states))
 906
 907 ;;;###autoload
 908 (defun desktop-save (dirname &optional release auto-save)
 909   "Save the desktop in a desktop file.
 910 Parameter DIRNAME specifies where to save the desktop file.
 911 Optional parameter RELEASE says whether we're done with this desktop.
 912 If AUTO-SAVE is non-nil, compare the saved contents to the one last saved,
 913 and don't save the buffer if they are the same."
 914   (interactive "DDirectory to save desktop file in: ")
 915   (setq desktop-dirname (file-name-as-directory (expand-file-name dirname)))
 916   (save-excursion
 917     (let ((eager desktop-restore-eager)
 918           (new-modtime (nth 5 (file-attributes (desktop-full-file-name)))))
 919       (when
 920           (or (not new-modtime)         ; nothing to overwrite
 921               (equal desktop-file-modtime new-modtime)
 922               (yes-or-no-p (if desktop-file-modtime
 923                                (if (> (float-time new-modtime) (float-time desktop-file-modtime))
 924                                    "Desktop file is more recent than the one loaded.  Save anyway? "
 925                                  "Desktop file isn't the one loaded.  Overwrite it? ")
 926                              "Current desktop was not loaded from a file.  Overwrite this desktop file? "))
 927               (unless release (error "Desktop file conflict")))
 928
 929         ;; If we're done with it, release the lock.
 930         ;; Otherwise, claim it if it's unclaimed or if we created it.
 931         (if release
 932             (desktop-release-lock)
 933           (unless (and new-modtime (desktop-owner)) (desktop-claim-lock)))
 934
 935         (with-temp-buffer
 936           (insert
 937            ";; -*- mode: emacs-lisp; coding: emacs-mule; -*-\n"
 938            desktop-header
 939            ";; Created " (current-time-string) "\n"
 940            ";; Desktop file format version " desktop-file-version "\n"
 941            ";; Emacs version " emacs-version "\n")
 942           (save-excursion (run-hooks 'desktop-save-hook))
 943           (goto-char (point-max))
 944           (insert "\n;; Global section:\n")
 945           ;; Called here because we save the window/frame state as a global
 946           ;; variable for compatibility with previous Emacsen.
 947           (desktop--save-windows)
 948           (mapc (function desktop-outvar) desktop-globals-to-save)
 949           (when (memq 'kill-ring desktop-globals-to-save)
 950             (insert
 951              "(setq kill-ring-yank-pointer (nthcdr "
 952              (int-to-string (- (length kill-ring) (length kill-ring-yank-pointer)))
 953              " kill-ring))\n"))
 954
 955           (insert "\n;; Buffer section -- buffers listed in same order as in buffer list:\n")
 956           (dolist (l (mapcar 'desktop-buffer-info (buffer-list)))
 957             (let ((base (pop l)))
 958               (when (apply 'desktop-save-buffer-p l)
 959                 (insert "("
 960                         (if (or (not (integerp eager))
 961                                 (if (zerop eager)
 962                                     nil
 963                                   (setq eager (1- eager))))
 964                             "desktop-create-buffer"
 965                           "desktop-append-buffer-args")
 966                         " "
 967                         desktop-file-version)
 968                 ;; If there's a non-empty base name, we save it instead of the buffer name
 969                 (when (and base (not (string= base "")))
 970                   (setcar (nthcdr 1 l) base))
 971                 (dolist (e l)
 972                   (insert "\n  " (desktop-value-to-string e)))
 973                 (insert ")\n\n"))))
 974
 975           (setq default-directory desktop-dirname)
 976           ;; If auto-saving, avoid writing if nothing has changed since the last write.
 977           ;; Don't check 300 characters of the header that contains the timestamp.
 978           (let ((checksum (and auto-save (md5 (current-buffer)
 979                                               (+ (point-min) 300) (point-max)
 980                                               'emacs-mule))))
 981             (unless (and auto-save (equal checksum desktop-file-checksum))
 982               (let ((coding-system-for-write 'emacs-mule))
 983                 (write-region (point-min) (point-max) (desktop-full-file-name) nil 'nomessage))
 984               (setq desktop-file-checksum checksum)
 985               ;; We remember when it was modified (which is presumably just now).
 986               (setq desktop-file-modtime (nth 5 (file-attributes (desktop-full-file-name)))))))))))
 987
 988 ;; ----------------------------------------------------------------------------
 989 ;;;###autoload
 990 (defun desktop-remove ()
 991   "Delete desktop file in `desktop-dirname'.
 992 This function also sets `desktop-dirname' to nil."
 993   (interactive)
 994   (when desktop-dirname
 995     (let ((filename (desktop-full-file-name)))
 996       (setq desktop-dirname nil)
 997       (when (file-exists-p filename)
 998         (delete-file filename)))))
 999
1000 (defvar desktop-buffer-args-list nil
1001   "List of args for `desktop-create-buffer'.")
1002
1003 (defvar desktop-lazy-timer nil)
1004
1005 ;; ----------------------------------------------------------------------------
1006 (defun desktop--find-frame-in-display (frames display)
1007   (let (result)
1008     (while (and frames (not result))
1009       (if (equal display (frame-parameter (car frames) 'display))
1010           (setq result (car frames))
1011         (setq frames (cdr frames))))
1012     result))
1013
1014 (defun desktop--make-full-frame (full display config)
1015   (let ((width (and (eq full 'fullheight) (cdr (assq 'width config))))
1016         (height (and (eq full 'fullwidth) (cdr (assq 'height config))))
1017         (params '((visibility)))
1018         frame)
1019     (when width
1020       (setq params (append `((user-size . t) (width . ,width)) params)))
1021     (when height
1022       (setq params (append `((user-size . t) (height . ,height)) params)))
1023     (setq frame (make-frame-on-display display params))
1024     (modify-frame-parameters frame config)
1025     frame))
1026
1027 (defun desktop--restore-windows ()
1028   "Restore window/frame configuration.
1029 Internal use only."
1030   (when (and desktop-save-windows desktop--saved-states)
1031     (let ((frames (frame-list))
1032           (selected nil))
1033       (dolist (state desktop--saved-states)
1034         (condition-case err
1035             (let* ((fconfig (car state))
1036                    (display (cdr (assq 'display fconfig)))
1037                    (full (cdr (assq 'fullscreen fconfig)))
1038                    (frame (and (not full)
1039                                (desktop--find-frame-in-display frames display))))
1040               (cond (full
1041                      ;; treat fullscreen/maximized frames specially
1042                      (setq frame (desktop--make-full-frame full display fconfig)))
1043                     (frame
1044                      ;; found a frame in the right display -- reuse
1045                      (setq frames (delq frame frames))
1046                      (modify-frame-parameters frame fconfig))
1047                     (t
1048                      ;; no frames in the display -- make a new one
1049                      (setq frame (make-frame-on-display display fconfig))))
1050               ;; restore windows
1051               (window-state-put (cdr state) (frame-root-window frame) 'safe)
1052               (unless selected (setq selected frame)))
1053           (error
1054            (message "Error restoring frame: %S" (error-message-string err)))))
1055       ;; make sure the original selected frame is visible and selected
1056       (unless (or (frame-parameter selected 'visibility) (daemonp))
1057         (modify-frame-parameters selected '((visibility . t))))
1058       (select-frame-set-input-focus selected)
1059       ;; delete any remaining frames
1060       (mapc #'delete-frame frames))))
1061
1062 ;;;###autoload
1063 (defun desktop-read (&optional dirname)
1064   "Read and process the desktop file in directory DIRNAME.
1065 Look for a desktop file in DIRNAME, or if DIRNAME is omitted, look in
1066 directories listed in `desktop-path'.  If a desktop file is found, it
1067 is processed and `desktop-after-read-hook' is run.  If no desktop file
1068 is found, clear the desktop and run `desktop-no-desktop-file-hook'.
1069 This function is a no-op when Emacs is running in batch mode.
1070 It returns t if a desktop file was loaded, nil otherwise."
1071   (interactive)
1072   (unless noninteractive
1073     (setq desktop-dirname
1074           (file-name-as-directory
1075            (expand-file-name
1076             (or
1077              ;; If DIRNAME is specified, use it.
1078              (and (< 0 (length dirname)) dirname)
1079              ;; Otherwise search desktop file in desktop-path.
1080              (let ((dirs desktop-path))
1081                (while (and dirs
1082                            (not (file-exists-p
1083                                  (desktop-full-file-name (car dirs)))))
1084                  (setq dirs (cdr dirs)))
1085                (and dirs (car dirs)))
1086              ;; If not found and `desktop-path' is non-nil, use its first element.
1087              (and desktop-path (car desktop-path))
1088              ;; Default: .emacs.d.
1089              user-emacs-directory))))
1090     (if (file-exists-p (desktop-full-file-name))
1091         ;; Desktop file found, but is it already in use?
1092         (let ((desktop-first-buffer nil)
1093               (desktop-buffer-ok-count 0)
1094               (desktop-buffer-fail-count 0)
1095               (owner (desktop-owner))
1096               ;; Avoid desktop saving during evaluation of desktop buffer.
1097               (desktop-save nil))
1098           (if (and owner
1099                    (memq desktop-load-locked-desktop '(nil ask))
1100                    (or (null desktop-load-locked-desktop)
1101                        (daemonp)
1102                        (not (y-or-n-p (format "Warning: desktop file appears to be in use by PID %s.\n\
1103 Using it may cause conflicts.  Use it anyway? " owner)))))
1104               (let ((default-directory desktop-dirname))
1105                 (setq desktop-dirname nil)
1106                 (run-hooks 'desktop-not-loaded-hook)
1107                 (unless desktop-dirname
1108                   (message "Desktop file in use; not loaded.")))
1109             (desktop-lazy-abort)
1110             ;; Evaluate desktop buffer and remember when it was modified.
1111             (load (desktop-full-file-name) t t t)
1112             (setq desktop-file-modtime (nth 5 (file-attributes (desktop-full-file-name))))
1113             ;; If it wasn't already, mark it as in-use, to bother other
1114             ;; desktop instances.
1115             (unless owner
1116               (condition-case nil
1117                   (desktop-claim-lock)
1118                 (file-error (message "Couldn't record use of desktop file")
1119                             (sit-for 1))))
1120
1121             ;; `desktop-create-buffer' puts buffers at end of the buffer list.
1122             ;; We want buffers existing prior to evaluating the desktop (and
1123             ;; not reused) to be placed at the end of the buffer list, so we
1124             ;; move them here.
1125             (mapc 'bury-buffer
1126                   (nreverse (cdr (memq desktop-first-buffer (nreverse (buffer-list))))))
1127             (switch-to-buffer (car (buffer-list)))
1128             (run-hooks 'desktop-delay-hook)
1129             (setq desktop-delay-hook nil)
1130             (desktop--restore-windows)
1131             (run-hooks 'desktop-after-read-hook)
1132             (message "Desktop: %d buffer%s restored%s%s."
1133                      desktop-buffer-ok-count
1134                      (if (= 1 desktop-buffer-ok-count) "" "s")
1135                      (if (< 0 desktop-buffer-fail-count)
1136                          (format ", %d failed to restore" desktop-buffer-fail-count)
1137                        "")
1138                      (if desktop-buffer-args-list
1139                          (format ", %d to restore lazily"
1140                                  (length desktop-buffer-args-list))
1141                        ""))
1142             ;; Bury the *Messages* buffer to not reshow it when burying
1143             ;; the buffer we switched to above.
1144             (when (buffer-live-p (get-buffer "*Messages*"))
1145               (bury-buffer "*Messages*"))
1146             ;; Clear all windows' previous and next buffers, these have
1147             ;; been corrupted by the `switch-to-buffer' calls in
1148             ;; `desktop-restore-file-buffer' (bug#11556).  This is a
1149             ;; brute force fix and should be replaced by a more subtle
1150             ;; strategy eventually.
1151             (walk-window-tree (lambda (window)
1152                                 (set-window-prev-buffers window nil)
1153                                 (set-window-next-buffers window nil)))
1154             t))
1155       ;; No desktop file found.
1156       (desktop-clear)
1157       (let ((default-directory desktop-dirname))
1158         (run-hooks 'desktop-no-desktop-file-hook))
1159       (message "No desktop file.")
1160       nil)))
1161
1162 ;; ----------------------------------------------------------------------------
1163 ;; Maintained for backward compatibility
1164 ;;;###autoload
1165 (defun desktop-load-default ()
1166   "Load the `default' start-up library manually.
1167 Also inhibit further loading of it."
1168   (declare (obsolete desktop-save-mode "22.1"))
1169   (unless inhibit-default-init          ; safety check
1170     (load "default" t t)
1171     (setq inhibit-default-init t)))
1172
1173 ;; ----------------------------------------------------------------------------
1174 ;;;###autoload
1175 (defun desktop-change-dir (dirname)
1176   "Change to desktop saved in DIRNAME.
1177 Kill the desktop as specified by variables `desktop-save-mode' and
1178 `desktop-save', then clear the desktop and load the desktop file in
1179 directory DIRNAME."
1180   (interactive "DChange to directory: ")
1181   (setq dirname (file-name-as-directory (expand-file-name dirname desktop-dirname)))
1182   (desktop-kill)
1183   (desktop-clear)
1184   (desktop-read dirname))
1185
1186 ;; ----------------------------------------------------------------------------
1187 ;;;###autoload
1188 (defun desktop-save-in-desktop-dir ()
1189   "Save the desktop in directory `desktop-dirname'."
1190   (interactive)
1191   (if desktop-dirname
1192       (desktop-save desktop-dirname)
1193     (call-interactively 'desktop-save))
1194   (message "Desktop saved in %s" (abbreviate-file-name desktop-dirname)))
1195
1196 ;; ----------------------------------------------------------------------------
1197 ;; Auto-Saving.
1198 (defvar desktop-auto-save-timer nil)
1199
1200 (defun desktop-auto-save ()
1201   "Save the desktop periodically.
1202 Called by the timer created in `desktop-auto-save-set-timer'."
1203   (when (and desktop-save-mode
1204              (integerp desktop-auto-save-timeout)
1205              (> desktop-auto-save-timeout 0)
1206              ;; Avoid desktop saving during lazy loading.
1207              (not desktop-lazy-timer)
1208              ;; Save only to own desktop file.
1209              (eq (emacs-pid) (desktop-owner))
1210              desktop-dirname)
1211     (desktop-save desktop-dirname nil t))
1212   (desktop-auto-save-set-timer))
1213
1214 (defun desktop-auto-save-set-timer ()
1215   "Reset the auto-save timer.
1216 Cancel any previous timer.  When `desktop-auto-save-timeout' is a positive
1217 integer, start a new timer to call `desktop-auto-save' in that many seconds."
1218   (when desktop-auto-save-timer
1219     (cancel-timer desktop-auto-save-timer)
1220     (setq desktop-auto-save-timer nil))
1221   (when (and (integerp desktop-auto-save-timeout)
1222              (> desktop-auto-save-timeout 0))
1223     (setq desktop-auto-save-timer
1224           (run-with-timer desktop-auto-save-timeout nil
1225                           'desktop-auto-save))))
1226
1227 ;; ----------------------------------------------------------------------------
1228 ;;;###autoload
1229 (defun desktop-revert ()
1230   "Revert to the last loaded desktop."
1231   (interactive)
1232   (unless desktop-dirname
1233     (error "Unknown desktop directory"))
1234   (unless (file-exists-p (desktop-full-file-name))
1235     (error "No desktop file found"))
1236   (desktop-clear)
1237   (desktop-read desktop-dirname))
1238
1239 (defvar desktop-buffer-major-mode)
1240 (defvar desktop-buffer-locals)
1241 (defvar auto-insert)  ; from autoinsert.el
1242 ;; ----------------------------------------------------------------------------
1243 (defun desktop-restore-file-buffer (buffer-filename
1244                                     _buffer-name
1245                                     _buffer-misc)
1246   "Restore a file buffer."
1247   (when buffer-filename
1248     (if (or (file-exists-p buffer-filename)
1249             (let ((msg (format "Desktop: File \"%s\" no longer exists."
1250                                buffer-filename)))
1251               (if desktop-missing-file-warning
1252                   (y-or-n-p (concat msg " Re-create buffer? "))
1253                 (message "%s" msg)
1254                 nil)))
1255         (let* ((auto-insert nil) ; Disable auto insertion
1256                (coding-system-for-read
1257                 (or coding-system-for-read
1258                     (cdr (assq 'buffer-file-coding-system
1259                                desktop-buffer-locals))))
1260                (buf (find-file-noselect buffer-filename)))
1261           (condition-case nil
1262               (switch-to-buffer buf)
1263             (error (pop-to-buffer buf)))
1264           (and (not (eq major-mode desktop-buffer-major-mode))
1265                (functionp desktop-buffer-major-mode)
1266                (funcall desktop-buffer-major-mode))
1267           buf)
1268       nil)))
1269
1270 (defun desktop-load-file (function)
1271   "Load the file where auto loaded FUNCTION is defined."
1272   (when (fboundp function)
1273     (autoload-do-load (symbol-function function) function)))
1274
1275 ;; ----------------------------------------------------------------------------
1276 ;; Create a buffer, load its file, set its mode, ...;
1277 ;; called from Desktop file only.
1278
1279 ;; Just to silence the byte compiler.
1280
1281 (defvar desktop-first-buffer)          ; Dynamically bound in `desktop-read'
1282
1283 ;; Bound locally in `desktop-read'.
1284 (defvar desktop-buffer-ok-count)
1285 (defvar desktop-buffer-fail-count)
1286
1287 (defun desktop-create-buffer
1288     (file-version
1289      buffer-filename
1290      buffer-name
1291      buffer-majormode
1292      buffer-minormodes
1293      buffer-point
1294      buffer-mark
1295      buffer-readonly
1296      buffer-misc
1297      &optional
1298      buffer-locals)
1299
1300   (let ((desktop-file-version       file-version)
1301         (desktop-buffer-file-name   buffer-filename)
1302         (desktop-buffer-name        buffer-name)
1303         (desktop-buffer-major-mode  buffer-majormode)
1304         (desktop-buffer-minor-modes buffer-minormodes)
1305         (desktop-buffer-point       buffer-point)
1306         (desktop-buffer-mark        buffer-mark)
1307         (desktop-buffer-read-only   buffer-readonly)
1308         (desktop-buffer-misc        buffer-misc)
1309         (desktop-buffer-locals      buffer-locals))
1310     ;; To make desktop files with relative file names possible, we cannot
1311     ;; allow `default-directory' to change. Therefore we save current buffer.
1312     (save-current-buffer
1313       ;; Give major mode module a chance to add a handler.
1314       (desktop-load-file desktop-buffer-major-mode)
1315       (let ((buffer-list (buffer-list))
1316             (result
1317              (condition-case-unless-debug err
1318                  (funcall (or (cdr (assq desktop-buffer-major-mode
1319                                          desktop-buffer-mode-handlers))
1320                               'desktop-restore-file-buffer)
1321                           desktop-buffer-file-name
1322                           desktop-buffer-name
1323                           desktop-buffer-misc)
1324                (error
1325                 (message "Desktop: Can't load buffer %s: %s"
1326                          desktop-buffer-name
1327                          (error-message-string err))
1328                 (when desktop-missing-file-warning (sit-for 1))
1329                 nil))))
1330         (if (bufferp result)
1331             (setq desktop-buffer-ok-count (1+ desktop-buffer-ok-count))
1332           (setq desktop-buffer-fail-count (1+ desktop-buffer-fail-count))
1333           (setq result nil))
1334         ;; Restore buffer list order with new buffer at end. Don't change
1335         ;; the order for old desktop files (old desktop module behavior).
1336         (unless (< desktop-file-version 206)
1337           (mapc 'bury-buffer buffer-list)
1338           (when result (bury-buffer result)))
1339         (when result
1340           (unless (or desktop-first-buffer (< desktop-file-version 206))
1341             (setq desktop-first-buffer result))
1342           (set-buffer result)
1343           (unless (equal (buffer-name) desktop-buffer-name)
1344             (rename-buffer desktop-buffer-name t))
1345           ;; minor modes
1346           (cond ((equal '(t) desktop-buffer-minor-modes) ; backwards compatible
1347                  (auto-fill-mode 1))
1348                 ((equal '(nil) desktop-buffer-minor-modes) ; backwards compatible
1349                  (auto-fill-mode 0))
1350                 (t
1351                  (dolist (minor-mode desktop-buffer-minor-modes)
1352                    ;; Give minor mode module a chance to add a handler.
1353                    (desktop-load-file minor-mode)
1354                    (let ((handler (cdr (assq minor-mode desktop-minor-mode-handlers))))
1355                      (if handler
1356                          (funcall handler desktop-buffer-locals)
1357                        (when (functionp minor-mode)
1358                          (funcall minor-mode 1)))))))
1359           ;; Even though point and mark are non-nil when written by
1360           ;; `desktop-save', they may be modified by handlers wanting to set
1361           ;; point or mark themselves.
1362           (when desktop-buffer-point
1363             (goto-char
1364              (condition-case err
1365                  ;; Evaluate point.  Thus point can be something like
1366                  ;; '(search-forward ...
1367                  (eval desktop-buffer-point)
1368                (error (message "%s" (error-message-string err)) 1))))
1369           (when desktop-buffer-mark
1370             (if (consp desktop-buffer-mark)
1371                 (progn
1372                   (set-mark (car desktop-buffer-mark))
1373                   (setq mark-active (car (cdr desktop-buffer-mark))))
1374               (set-mark desktop-buffer-mark)))
1375           ;; Never override file system if the file really is read-only marked.
1376           (when desktop-buffer-read-only (setq buffer-read-only desktop-buffer-read-only))
1377           (while desktop-buffer-locals
1378             (let ((this (car desktop-buffer-locals)))
1379               (if (consp this)
1380                   ;; an entry of this form `(symbol . value)'
1381                   (progn
1382                     (make-local-variable (car this))
1383                     (set (car this) (cdr this)))
1384                 ;; an entry of the form `symbol'
1385                 (make-local-variable this)
1386                 (makunbound this)))
1387             (setq desktop-buffer-locals (cdr desktop-buffer-locals))))))))
1388
1389 ;; ----------------------------------------------------------------------------
1390 ;; Backward compatibility -- update parameters to 205 standards.
1391 (defun desktop-buffer (buffer-filename buffer-name buffer-majormode
1392                        mim pt mk ro tl fc cfs cr buffer-misc)
1393   (desktop-create-buffer 205 buffer-filename buffer-name
1394                          buffer-majormode (cdr mim) pt mk ro
1395                          buffer-misc
1396                          (list (cons 'truncate-lines tl)
1397                                (cons 'fill-column fc)
1398                                (cons 'case-fold-search cfs)
1399                                (cons 'case-replace cr)
1400                                (cons 'overwrite-mode (car mim)))))
1401
1402 (defun desktop-append-buffer-args (&rest args)
1403   "Append ARGS at end of `desktop-buffer-args-list'.
1404 ARGS must be an argument list for `desktop-create-buffer'."
1405   (setq desktop-buffer-args-list (nconc desktop-buffer-args-list (list args)))
1406   (unless desktop-lazy-timer
1407     (setq desktop-lazy-timer
1408           (run-with-idle-timer desktop-lazy-idle-delay t 'desktop-idle-create-buffers))))
1409
1410 (defun desktop-lazy-create-buffer ()
1411   "Pop args from `desktop-buffer-args-list', create buffer and bury it."
1412   (when desktop-buffer-args-list
1413     (let* ((remaining (length desktop-buffer-args-list))
1414            (args (pop desktop-buffer-args-list))
1415            (buffer-name (nth 2 args))
1416            (msg (format "Desktop lazily opening %s (%s remaining)..."
1417                             buffer-name remaining)))
1418       (when desktop-lazy-verbose
1419         (message "%s" msg))
1420       (let ((desktop-first-buffer nil)
1421             (desktop-buffer-ok-count 0)
1422             (desktop-buffer-fail-count 0))
1423         (apply 'desktop-create-buffer args)
1424         (run-hooks 'desktop-delay-hook)
1425         (setq desktop-delay-hook nil)
1426         (bury-buffer (get-buffer buffer-name))
1427         (when desktop-lazy-verbose
1428           (message "%s%s" msg (if (> desktop-buffer-ok-count 0) "done" "failed")))))))
1429
1430 (defun desktop-idle-create-buffers ()
1431   "Create buffers until the user does something, then stop.
1432 If there are no buffers left to create, kill the timer."
1433   (let ((repeat 1))
1434     (while (and repeat desktop-buffer-args-list)
1435       (save-window-excursion
1436         (desktop-lazy-create-buffer))
1437       (setq repeat (sit-for 0.2))
1438     (unless desktop-buffer-args-list
1439       (cancel-timer desktop-lazy-timer)
1440       (setq desktop-lazy-timer nil)
1441       (message "Lazy desktop load complete")
1442       (sit-for 3)
1443       (message "")))))
1444
1445 (defun desktop-lazy-complete ()
1446   "Run the desktop load to completion."
1447   (interactive)
1448   (let ((desktop-lazy-verbose t))
1449     (while desktop-buffer-args-list
1450       (save-window-excursion
1451         (desktop-lazy-create-buffer)))
1452     (message "Lazy desktop load complete")))
1453
1454 (defun desktop-lazy-abort ()
1455   "Abort lazy loading of the desktop."
1456   (interactive)
1457   (when desktop-lazy-timer
1458     (cancel-timer desktop-lazy-timer)
1459     (setq desktop-lazy-timer nil))
1460   (when desktop-buffer-args-list
1461     (setq desktop-buffer-args-list nil)
1462     (when (called-interactively-p 'interactive)
1463       (message "Lazy desktop load aborted"))))
1464
1465 ;; ----------------------------------------------------------------------------
1466 ;; When `desktop-save-mode' is non-nil and "--no-desktop" is not specified on the
1467 ;; command line, we do the rest of what it takes to use desktop, but do it
1468 ;; after finishing loading the init file.
1469 ;; We cannot use `command-switch-alist' to process "--no-desktop" because these
1470 ;; functions are processed after `after-init-hook'.
1471 (add-hook
1472   'after-init-hook
1473   (lambda ()
1474     (let ((key "--no-desktop"))
1475       (when (member key command-line-args)
1476         (setq command-line-args (delete key command-line-args))
1477         (setq desktop-save-mode nil)))
1478     (when desktop-save-mode
1479       (desktop-read)
1480       (desktop-auto-save-set-timer)
1481       (setq inhibit-startup-screen t))))
1482
1483 ;; So we can restore vc-dir buffers.
1484 (autoload 'vc-dir-mode "vc-dir" nil t)
1485
1486 (provide 'desktop)
1487
1488 ;;; desktop.el ends here