lisp/desktop.el

   1 ;;; desktop.el --- save partial status of Emacs when killed
   2
   3 ;; Copyright (C) 1993, 1994, 1995, 1997, 2000, 2001, 2002, 2003,
   4 ;;   2004, 2005, 2006, 2007, 2008, 2009, 2010
   5 ;;   Free Software Foundation, Inc.
   6
   7 ;; Author: Morten Welinder <terra@diku.dk>
   8 ;; Keywords: convenience
   9 ;; Favourite-brand-of-beer: None, I hate beer.
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software: you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation, either version 3 of the License, or
  16 ;; (at your option) any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  25
  26 ;;; Commentary:
  27
  28 ;; Save the Desktop, i.e.,
  29 ;;      - some global variables
  30 ;;      - the list of buffers with associated files.  For each buffer also
  31 ;;              - the major mode
  32 ;;              - the default directory
  33 ;;              - the point
  34 ;;              - the mark & mark-active
  35 ;;              - buffer-read-only
  36 ;;              - some local variables
  37
  38 ;; To use this, use customize to turn on desktop-save-mode or add the
  39 ;; following line somewhere in your .emacs file:
  40 ;;
  41 ;;      (desktop-save-mode 1)
  42 ;;
  43 ;; For further usage information, look at the section
  44 ;; (info "(emacs)Saving Emacs Sessions") in the GNU Emacs Manual.
  45
  46 ;; When the desktop module is loaded, the function `desktop-kill' is
  47 ;; added to the `kill-emacs-hook'.  This function is responsible for
  48 ;; saving the desktop when Emacs is killed.  Furthermore an anonymous
  49 ;; function is added to the `after-init-hook'.  This function is
  50 ;; responsible for loading the desktop when Emacs is started.
  51
  52 ;; Special handling.
  53 ;; -----------------
  54 ;; Variables `desktop-buffer-mode-handlers' and `desktop-minor-mode-handlers'
  55 ;; are supplied to handle special major and minor modes respectively.
  56 ;; `desktop-buffer-mode-handlers' is an alist of major mode specific functions
  57 ;; to restore a desktop buffer.  Elements must have the form
  58 ;;
  59 ;;    (MAJOR-MODE . RESTORE-BUFFER-FUNCTION).
  60 ;;
  61 ;; Functions listed are called by `desktop-create-buffer' when `desktop-read'
  62 ;; evaluates the desktop file.  Buffers with a major mode not specified here,
  63 ;; are restored by the default handler `desktop-restore-file-buffer'.
  64 ;; `desktop-minor-mode-handlers' is an alist of functions to restore
  65 ;; non-standard minor modes.  Elements must have the form
  66 ;;
  67 ;;    (MINOR-MODE . RESTORE-FUNCTION).
  68 ;;
  69 ;; Functions are called by `desktop-create-buffer' to restore minor modes.
  70 ;; Minor modes not specified here, are restored by the standard minor mode
  71 ;; function.  If you write a module that defines a major or minor mode that
  72 ;; needs a special handler, then place code like
  73
  74 ;;    (defun foo-restore-desktop-buffer
  75 ;;    ...
  76 ;;    (add-to-list 'desktop-buffer-mode-handlers
  77 ;;                 '(foo-mode . foo-restore-desktop-buffer))
  78
  79 ;; or
  80
  81 ;;    (defun bar-desktop-restore
  82 ;;    ...
  83 ;;    (add-to-list 'desktop-minor-mode-handlers
  84 ;;                 '(bar-mode . bar-desktop-restore))
  85
  86 ;; in the module itself, and make sure that the mode function is
  87 ;; autoloaded.  See the docstrings of `desktop-buffer-mode-handlers' and
  88 ;; `desktop-minor-mode-handlers' for more info.
  89
  90 ;; Minor modes.
  91 ;; ------------
  92 ;; Conventional minor modes (see node "Minor Mode Conventions" in the elisp
  93 ;; manual) are handled in the following way:
  94 ;; When `desktop-save' saves the state of a buffer to the desktop file, it
  95 ;; saves as `desktop-minor-modes' the list of names of those variables in
  96 ;; `minor-mode-alist' that have a non-nil value.
  97 ;; When `desktop-create' restores the buffer, each of the symbols in
  98 ;; `desktop-minor-modes' is called as function with parameter 1.
  99 ;; The variables `desktop-minor-mode-table' and `desktop-minor-mode-handlers'
 100 ;; are used to handle non-conventional minor modes.  `desktop-save' uses
 101 ;; `desktop-minor-mode-table' to map minor mode variables to minor mode
 102 ;; functions before writing `desktop-minor-modes'.  If a minor mode has a
 103 ;; variable name that is different form its function name, an entry
 104
 105 ;;    (NAME RESTORE-FUNCTION)
 106
 107 ;; should be added to `desktop-minor-mode-table'.  If a minor mode should not
 108 ;; be restored, RESTORE-FUNCTION should be set to nil.  `desktop-create' uses
 109 ;; `desktop-minor-mode-handlers' to lookup minor modes that needs a restore
 110 ;; function different from the usual minor mode function.
 111 ;; ---------------------------------------------------------------------------
 112
 113 ;; By the way: don't use desktop.el to customize Emacs -- the file .emacs
 114 ;; in your home directory is used for that.  Saving global default values
 115 ;; for buffers is an example of misuse.
 116
 117 ;; PLEASE NOTE: The kill ring can be saved as specified by the variable
 118 ;; `desktop-globals-to-save' (by default it isn't).  This may result in saving
 119 ;; things you did not mean to keep.  Use M-x desktop-clear RET.
 120
 121 ;; Thanks to  hetrick@phys.uva.nl (Jim Hetrick)      for useful ideas.
 122 ;;            avk@rtsg.mot.com (Andrew V. Klein)     for a dired tip.
 123 ;;            chris@tecc.co.uk (Chris Boucher)       for a mark tip.
 124 ;;            f89-kam@nada.kth.se (Klas Mellbourn)   for a mh-e tip.
 125 ;;            kifer@sbkifer.cs.sunysb.edu (M. Kifer) for a bug hunt.
 126 ;;            treese@lcs.mit.edu (Win Treese)        for ange-ftp tips.
 127 ;;            pot@cnuce.cnr.it (Francesco Potorti`)  for misc. tips.
 128 ;; ---------------------------------------------------------------------------
 129 ;; TODO:
 130 ;;
 131 ;; Save window configuration.
 132 ;; Recognize more minor modes.
 133 ;; Save mark rings.
 134
 135 ;;; Code:
 136
 137 (defvar desktop-file-version "206"
 138   "Version number of desktop file format.
 139 Written into the desktop file and used at desktop read to provide
 140 backward compatibility.")
 141
 142 ;; ----------------------------------------------------------------------------
 143 ;; USER OPTIONS -- settings you might want to play with.
 144 ;; ----------------------------------------------------------------------------
 145
 146 (defgroup desktop nil
 147   "Save status of Emacs when you exit."
 148   :group 'frames)
 149
 150 ;;;###autoload
 151 (define-minor-mode desktop-save-mode
 152   "Toggle desktop saving mode.
 153 With numeric ARG, turn desktop saving on if ARG is positive, off
 154 otherwise.  If desktop saving is turned on, the state of Emacs is
 155 saved from one session to another.  See variable `desktop-save'
 156 and function `desktop-read' for details."
 157   :global t
 158   :group 'desktop)
 159
 160 ;; Maintained for backward compatibility
 161 (define-obsolete-variable-alias 'desktop-enable
 162                                 'desktop-save-mode "22.1")
 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-load-locked-desktop 'ask
 193   "Specifies whether the desktop should be loaded if locked.
 194 Possible values are:
 195    t    -- load anyway.
 196    nil  -- don't load.
 197    ask  -- ask the user.
 198 If the value is nil, or `ask' and the user chooses not to load the desktop,
 199 the normal hook `desktop-not-loaded-hook' is run."
 200   :type
 201   '(choice
 202     (const :tag "Load anyway" t)
 203     (const :tag "Don't load" nil)
 204     (const :tag "Ask the user" ask))
 205   :group 'desktop
 206   :version "22.2")
 207
 208 (define-obsolete-variable-alias 'desktop-basefilename
 209                                 'desktop-base-file-name "22.1")
 210
 211 (defcustom desktop-base-file-name
 212   (convert-standard-filename ".emacs.desktop")
 213   "Name of file for Emacs desktop, excluding the directory part."
 214   :type 'file
 215   :group 'desktop)
 216
 217 (defcustom desktop-base-lock-name
 218   (convert-standard-filename ".emacs.desktop.lock")
 219   "Name of lock file for Emacs desktop, excluding the directory part."
 220   :type 'file
 221   :group 'desktop
 222   :version "22.2")
 223
 224 (defcustom desktop-path (list "." user-emacs-directory "~")
 225   "List of directories to search for the desktop file.
 226 The base name of the file is specified in `desktop-base-file-name'."
 227   :type '(repeat directory)
 228   :group 'desktop
 229   :version "22.1")
 230
 231 (defcustom desktop-missing-file-warning nil
 232   "If non-nil, offer to recreate the buffer of a deleted file.
 233 Also pause for a moment to display message about errors signaled in
 234 `desktop-buffer-mode-handlers'.
 235
 236 If nil, just print error messages in the message buffer."
 237   :type 'boolean
 238   :group 'desktop
 239   :version "22.1")
 240
 241 (defcustom desktop-no-desktop-file-hook nil
 242   "Normal hook run when `desktop-read' can't find a desktop file.
 243 Run in the directory in which the desktop file was sought.
 244 May be used to show a dired buffer."
 245   :type 'hook
 246   :group 'desktop
 247   :version "22.1")
 248
 249 (defcustom desktop-not-loaded-hook nil
 250   "Normal hook run when the user declines to re-use a desktop file.
 251 Run in the directory in which the desktop file was found.
 252 May be used to deal with accidental multiple Emacs jobs."
 253   :type 'hook
 254   :group 'desktop
 255   :options '(desktop-save-mode-off save-buffers-kill-emacs)
 256   :version "22.2")
 257
 258 (defcustom desktop-after-read-hook nil
 259   "Normal hook run after a successful `desktop-read'.
 260 May be used to show a buffer list."
 261   :type 'hook
 262   :group 'desktop
 263   :options '(list-buffers)
 264   :version "22.1")
 265
 266 (defcustom desktop-save-hook nil
 267   "Normal hook run before the desktop is saved in a desktop file.
 268 Run with the desktop buffer current with only the header present.
 269 May be used to add to the desktop code or to truncate history lists,
 270 for example."
 271   :type 'hook
 272   :group 'desktop)
 273
 274 (defcustom desktop-globals-to-save
 275   '(desktop-missing-file-warning
 276     tags-file-name
 277     tags-table-list
 278     search-ring
 279     regexp-search-ring
 280     register-alist
 281     file-name-history)
 282   "List of global variables saved by `desktop-save'.
 283 An element may be variable name (a symbol) or a cons cell of the form
 284 \(VAR . MAX-SIZE), which means to truncate VAR's value to at most
 285 MAX-SIZE elements (if the value is a list) before saving the value.
 286 Feature: Saving `kill-ring' implies saving `kill-ring-yank-pointer'."
 287   :type '(repeat (restricted-sexp :match-alternatives (symbolp consp)))
 288   :group 'desktop)
 289
 290 (defcustom desktop-globals-to-clear
 291   '(kill-ring
 292     kill-ring-yank-pointer
 293     search-ring
 294     search-ring-yank-pointer
 295     regexp-search-ring
 296     regexp-search-ring-yank-pointer)
 297   "List of global variables that `desktop-clear' will clear.
 298 An element may be variable name (a symbol) or a cons cell of the form
 299 \(VAR . FORM).  Symbols are set to nil and for cons cells VAR is set
 300 to the value obtained by evaluating FORM."
 301   :type '(repeat (restricted-sexp :match-alternatives (symbolp consp)))
 302   :group 'desktop
 303   :version "22.1")
 304
 305 (defcustom desktop-clear-preserve-buffers
 306   '("\\*scratch\\*" "\\*Messages\\*" "\\*server\\*" "\\*tramp/.+\\*"
 307     "\\*Warnings\\*")
 308   "List of buffers that `desktop-clear' should not delete.
 309 Each element is a regular expression.  Buffers with a name matched by any of
 310 these won't be deleted."
 311   :version "23.3"                       ; added Warnings - bug#6336
 312   :type '(repeat string)
 313   :group 'desktop)
 314
 315 ;;;###autoload
 316 (defcustom desktop-locals-to-save
 317   '(desktop-locals-to-save  ; Itself!  Think it over.
 318     truncate-lines
 319     case-fold-search
 320     case-replace
 321     fill-column
 322     overwrite-mode
 323     change-log-default-name
 324     line-number-mode
 325     column-number-mode
 326     size-indication-mode
 327     buffer-file-coding-system
 328     indent-tabs-mode
 329     tab-width
 330     indicate-buffer-boundaries
 331     indicate-empty-lines
 332     show-trailing-whitespace)
 333   "List of local variables to save for each buffer.
 334 The variables are saved only when they really are local.  Conventional minor
 335 modes are restored automatically; they should not be listed here."
 336   :type '(repeat symbol)
 337   :group 'desktop)
 338
 339 (defcustom desktop-buffers-not-to-save nil
 340   "Regexp identifying buffers that are to be excluded from saving."
 341   :type '(choice (const :tag "None" nil)
 342                  regexp)
 343   :version "23.2"                       ; set to nil
 344   :group 'desktop)
 345
 346 ;; Skip tramp and ange-ftp files
 347 (defcustom desktop-files-not-to-save
 348   "\\(^/[^/:]*:\\|(ftp)$\\)"
 349   "Regexp identifying files whose buffers are to be excluded from saving."
 350   :type '(choice (const :tag "None" nil)
 351                  regexp)
 352   :group 'desktop)
 353
 354 ;; We skip TAGS files to save time (tags-file-name is saved instead).
 355 (defcustom desktop-modes-not-to-save
 356   '(tags-table-mode)
 357   "List of major modes whose buffers should not be saved."
 358   :type '(repeat symbol)
 359   :group 'desktop)
 360
 361 (defcustom desktop-file-name-format 'absolute
 362   "Format in which desktop file names should be saved.
 363 Possible values are:
 364    absolute -- Absolute file name.
 365    tilde    -- Relative to ~.
 366    local    -- Relative to directory of desktop file."
 367   :type '(choice (const absolute) (const tilde) (const local))
 368   :group 'desktop
 369   :version "22.1")
 370
 371 (defcustom desktop-restore-eager t
 372   "Number of buffers to restore immediately.
 373 Remaining buffers are restored lazily (when Emacs is idle).
 374 If value is t, all buffers are restored immediately."
 375   :type '(choice (const t) integer)
 376   :group 'desktop
 377   :version "22.1")
 378
 379 (defcustom desktop-lazy-verbose t
 380   "Verbose reporting of lazily created buffers."
 381   :type 'boolean
 382   :group 'desktop
 383   :version "22.1")
 384
 385 (defcustom desktop-lazy-idle-delay 5
 386   "Idle delay before starting to create buffers.
 387 See `desktop-restore-eager'."
 388   :type 'integer
 389   :group 'desktop
 390   :version "22.1")
 391
 392 ;;;###autoload
 393 (defvar desktop-save-buffer nil
 394   "When non-nil, save buffer status in desktop file.
 395 This variable becomes buffer local when set.
 396
 397 If the value is a function, it is called by `desktop-save' with argument
 398 DESKTOP-DIRNAME to obtain auxiliary information to save in the desktop
 399 file along with the state of the buffer for which it was called.
 400
 401 When file names are returned, they should be formatted using the call
 402 \"(desktop-file-name FILE-NAME DESKTOP-DIRNAME)\".
 403
 404 Later, when `desktop-read' evaluates the desktop file, auxiliary information
 405 is passed as the argument DESKTOP-BUFFER-MISC to functions in
 406 `desktop-buffer-mode-handlers'.")
 407 (make-variable-buffer-local 'desktop-save-buffer)
 408 (make-obsolete-variable 'desktop-buffer-modes-to-save
 409                         'desktop-save-buffer "22.1")
 410 (make-obsolete-variable 'desktop-buffer-misc-functions
 411                         'desktop-save-buffer "22.1")
 412
 413 ;;;###autoload
 414 (defvar desktop-buffer-mode-handlers
 415   nil
 416   "Alist of major mode specific functions to restore a desktop buffer.
 417 Functions listed are called by `desktop-create-buffer' when `desktop-read'
 418 evaluates the desktop file.  List elements must have the form
 419
 420    (MAJOR-MODE . RESTORE-BUFFER-FUNCTION).
 421
 422 Buffers with a major mode not specified here, are restored by the default
 423 handler `desktop-restore-file-buffer'.
 424
 425 Handlers are called with argument list
 426
 427    (DESKTOP-BUFFER-FILE-NAME DESKTOP-BUFFER-NAME DESKTOP-BUFFER-MISC)
 428
 429 Furthermore, they may use the following variables:
 430
 431    desktop-file-version
 432    desktop-buffer-major-mode
 433    desktop-buffer-minor-modes
 434    desktop-buffer-point
 435    desktop-buffer-mark
 436    desktop-buffer-read-only
 437    desktop-buffer-locals
 438
 439 If a handler returns a buffer, then the saved mode settings
 440 and variable values for that buffer are copied into it.
 441
 442 Modules that define a major mode that needs a special handler should contain
 443 code like
 444
 445    (defun foo-restore-desktop-buffer
 446    ...
 447    (add-to-list 'desktop-buffer-mode-handlers
 448                 '(foo-mode . foo-restore-desktop-buffer))
 449
 450 Furthermore the major mode function must be autoloaded.")
 451
 452 ;;;###autoload
 453 (put 'desktop-buffer-mode-handlers 'risky-local-variable t)
 454 (make-obsolete-variable 'desktop-buffer-handlers
 455                         'desktop-buffer-mode-handlers "22.1")
 456
 457 (defcustom desktop-minor-mode-table
 458   '((auto-fill-function auto-fill-mode)
 459     (vc-mode nil)
 460     (vc-dired-mode nil)
 461     (erc-track-minor-mode nil)
 462     (savehist-mode nil))
 463   "Table mapping minor mode variables to minor mode functions.
 464 Each entry has the form (NAME RESTORE-FUNCTION).
 465 NAME is the name of the buffer-local variable indicating that the minor
 466 mode is active.  RESTORE-FUNCTION is the function to activate the minor mode.
 467 RESTORE-FUNCTION nil means don't try to restore the minor mode.
 468 Only minor modes for which the name of the buffer-local variable
 469 and the name of the minor mode function are different have to be added to
 470 this table.  See also `desktop-minor-mode-handlers'."
 471   :type 'sexp
 472   :group 'desktop)
 473
 474 ;;;###autoload
 475 (defvar desktop-minor-mode-handlers
 476   nil
 477   "Alist of functions to restore non-standard minor modes.
 478 Functions are called by `desktop-create-buffer' to restore minor modes.
 479 List elements must have the form
 480
 481    (MINOR-MODE . RESTORE-FUNCTION).
 482
 483 Minor modes not specified here, are restored by the standard minor mode
 484 function.
 485
 486 Handlers are called with argument list
 487
 488    (DESKTOP-BUFFER-LOCALS)
 489
 490 Furthermore, they may use the following variables:
 491
 492    desktop-file-version
 493    desktop-buffer-file-name
 494    desktop-buffer-name
 495    desktop-buffer-major-mode
 496    desktop-buffer-minor-modes
 497    desktop-buffer-point
 498    desktop-buffer-mark
 499    desktop-buffer-read-only
 500    desktop-buffer-misc
 501
 502 When a handler is called, the buffer has been created and the major mode has
 503 been set, but local variables listed in desktop-buffer-locals has not yet been
 504 created and set.
 505
 506 Modules that define a minor mode that needs a special handler should contain
 507 code like
 508
 509    (defun foo-desktop-restore
 510    ...
 511    (add-to-list 'desktop-minor-mode-handlers
 512                 '(foo-mode . foo-desktop-restore))
 513
 514 Furthermore the minor mode function must be autoloaded.
 515
 516 See also `desktop-minor-mode-table'.")
 517
 518 ;;;###autoload
 519 (put 'desktop-minor-mode-handlers 'risky-local-variable t)
 520
 521 ;; ----------------------------------------------------------------------------
 522 (defvar desktop-dirname nil
 523   "The directory in which the desktop file should be saved.")
 524
 525 (defun desktop-full-file-name (&optional dirname)
 526   "Return the full name of the desktop file in DIRNAME.
 527 DIRNAME omitted or nil means use `desktop-dirname'."
 528   (expand-file-name desktop-base-file-name (or dirname desktop-dirname)))
 529
 530 (defun desktop-full-lock-name (&optional dirname)
 531   "Return the full name of the desktop lock file in DIRNAME.
 532 DIRNAME omitted or nil means use `desktop-dirname'."
 533   (expand-file-name desktop-base-lock-name (or dirname desktop-dirname)))
 534
 535 (defconst desktop-header
 536 ";; --------------------------------------------------------------------------
 537 ;; Desktop File for Emacs
 538 ;; --------------------------------------------------------------------------
 539 " "*Header to place in Desktop file.")
 540
 541 (defvar desktop-delay-hook nil
 542   "Hooks run after all buffers are loaded; intended for internal use.")
 543
 544 ;; ----------------------------------------------------------------------------
 545 ;; Desktop file conflict detection
 546 (defvar desktop-file-modtime nil
 547   "When the desktop file was last modified to the knowledge of this Emacs.
 548 Used to detect desktop file conflicts.")
 549
 550 (defun desktop-owner (&optional dirname)
 551   "Return the PID of the Emacs process that owns the desktop file in DIRNAME.
 552 Return nil if no desktop file found or no Emacs process is using it.
 553 DIRNAME omitted or nil means use `desktop-dirname'."
 554   (let (owner)
 555     (and (file-exists-p (desktop-full-lock-name dirname))
 556          (condition-case nil
 557              (with-temp-buffer
 558                (insert-file-contents-literally (desktop-full-lock-name dirname))
 559                (goto-char (point-min))
 560                (setq owner (read (current-buffer)))
 561                (integerp owner))
 562            (error nil))
 563          owner)))
 564
 565 (defun desktop-claim-lock (&optional dirname)
 566   "Record this Emacs process as the owner of the desktop file in DIRNAME.
 567 DIRNAME omitted or nil means use `desktop-dirname'."
 568   (write-region (number-to-string (emacs-pid)) nil
 569                 (desktop-full-lock-name dirname)))
 570
 571 (defun desktop-release-lock (&optional dirname)
 572   "Remove the lock file for the desktop in DIRNAME.
 573 DIRNAME omitted or nil means use `desktop-dirname'."
 574   (let ((file (desktop-full-lock-name dirname)))
 575     (when (file-exists-p file) (delete-file file))))
 576
 577 ;; ----------------------------------------------------------------------------
 578 (defun desktop-truncate (list n)
 579   "Truncate LIST to at most N elements destructively."
 580   (let ((here (nthcdr (1- n) list)))
 581     (when (consp here)
 582       (setcdr here nil))))
 583
 584 ;; ----------------------------------------------------------------------------
 585 ;;;###autoload
 586 (defun desktop-clear ()
 587   "Empty the Desktop.
 588 This kills all buffers except for internal ones and those with names matched by
 589 a regular expression in the list `desktop-clear-preserve-buffers'.
 590 Furthermore, it clears the variables listed in `desktop-globals-to-clear'."
 591   (interactive)
 592   (desktop-lazy-abort)
 593   (dolist (var desktop-globals-to-clear)
 594     (if (symbolp var)
 595         (eval `(setq-default ,var nil))
 596       (eval `(setq-default ,(car var) ,(cdr var)))))
 597   (let ((buffers (buffer-list))
 598         (preserve-regexp (concat "^\\("
 599                                  (mapconcat (lambda (regexp)
 600                                               (concat "\\(" regexp "\\)"))
 601                                             desktop-clear-preserve-buffers
 602                                             "\\|")
 603                                  "\\)$")))
 604     (while buffers
 605       (let ((bufname (buffer-name (car buffers))))
 606          (or
 607            (null bufname)
 608            (string-match preserve-regexp bufname)
 609            ;; Don't kill buffers made for internal purposes.
 610            (and (not (equal bufname "")) (eq (aref bufname 0) ?\s))
 611            (kill-buffer (car buffers))))
 612       (setq buffers (cdr buffers))))
 613   (delete-other-windows))
 614
 615 ;; ----------------------------------------------------------------------------
 616 (add-hook 'kill-emacs-hook 'desktop-kill)
 617
 618 (defun desktop-kill ()
 619   "If `desktop-save-mode' is non-nil, do what `desktop-save' says to do.
 620 If the desktop should be saved and `desktop-dirname'
 621 is nil, ask the user where to save the desktop."
 622   (when (and desktop-save-mode
 623              (let ((exists (file-exists-p (desktop-full-file-name))))
 624                (or (eq desktop-save t)
 625                    (and exists (eq desktop-save 'if-exists))
 626                    ;; If it exists, but we aren't using it, we are going
 627                    ;; to ask for a new directory below.
 628                    (and exists desktop-dirname (eq desktop-save 'ask-if-new))
 629                    (and
 630                     (or (memq desktop-save '(ask ask-if-new))
 631                         (and exists (eq desktop-save 'ask-if-exists)))
 632                     (y-or-n-p "Save desktop? ")))))
 633     (unless desktop-dirname
 634       (setq desktop-dirname
 635             (file-name-as-directory
 636              (expand-file-name
 637               (read-directory-name "Directory for desktop file: " nil nil t)))))
 638     (condition-case err
 639         (desktop-save desktop-dirname t)
 640       (file-error
 641        (unless (yes-or-no-p "Error while saving the desktop.  Ignore? ")
 642          (signal (car err) (cdr err))))))
 643   ;; If we own it, we don't anymore.
 644   (when (eq (emacs-pid) (desktop-owner)) (desktop-release-lock)))
 645
 646 ;; ----------------------------------------------------------------------------
 647 (defun desktop-list* (&rest args)
 648   (if (null (cdr args))
 649       (car args)
 650     (setq args (nreverse args))
 651     (let ((value (cons (nth 1 args) (car args))))
 652       (setq args (cdr (cdr args)))
 653       (while args
 654         (setq value (cons (car args) value))
 655         (setq args (cdr args)))
 656       value)))
 657
 658 ;; ----------------------------------------------------------------------------
 659 (defun desktop-buffer-info (buffer)
 660   (set-buffer buffer)
 661   (list
 662    ;; base name of the buffer; replaces the buffer name if managed by uniquify
 663    (and (fboundp 'uniquify-buffer-base-name) (uniquify-buffer-base-name))
 664    ;; basic information
 665    (desktop-file-name (buffer-file-name) desktop-dirname)
 666    (buffer-name)
 667    major-mode
 668    ;; minor modes
 669    (let (ret)
 670      (mapc
 671       #'(lambda (minor-mode)
 672           (and (boundp minor-mode)
 673                (symbol-value minor-mode)
 674                (let* ((special (assq minor-mode desktop-minor-mode-table))
 675                       (value (cond (special (cadr special))
 676                                    ((functionp minor-mode) minor-mode))))
 677                  (when value (add-to-list 'ret value)))))
 678       (mapcar #'car minor-mode-alist))
 679      ret)
 680    ;; point and mark, and read-only status
 681    (point)
 682    (list (mark t) mark-active)
 683    buffer-read-only
 684    ;; auxiliary information
 685    (when (functionp desktop-save-buffer)
 686      (funcall desktop-save-buffer desktop-dirname))
 687    ;; local variables
 688    (let ((locals desktop-locals-to-save)
 689          (loclist (buffer-local-variables))
 690          (ll))
 691      (while locals
 692        (let ((here (assq (car locals) loclist)))
 693          (if here
 694              (setq ll (cons here ll))
 695            (when (member (car locals) loclist)
 696              (setq ll (cons (car locals) ll)))))
 697        (setq locals (cdr locals)))
 698      ll)))
 699
 700 ;; ----------------------------------------------------------------------------
 701 (defun desktop-internal-v2s (value)
 702   "Convert VALUE to a pair (QUOTE . TXT); (eval (read TXT)) gives VALUE.
 703 TXT is a string that when read and evaluated yields value.
 704 QUOTE may be `may' (value may be quoted),
 705 `must' (values must be quoted), or nil (value may not be quoted)."
 706   (cond
 707     ((or (numberp value) (null value) (eq t value) (keywordp value))
 708      (cons 'may (prin1-to-string value)))
 709     ((stringp value)
 710      (let ((copy (copy-sequence value)))
 711        (set-text-properties 0 (length copy) nil copy)
 712        ;; Get rid of text properties because we cannot read them
 713        (cons 'may (prin1-to-string copy))))
 714     ((symbolp value)
 715      (cons 'must (prin1-to-string value)))
 716     ((vectorp value)
 717      (let* ((special nil)
 718             (pass1 (mapcar
 719                     (lambda (el)
 720                       (let ((res (desktop-internal-v2s el)))
 721                         (if (null (car res))
 722                             (setq special t))
 723                         res))
 724                     value)))
 725        (if special
 726            (cons nil (concat "(vector "
 727                              (mapconcat (lambda (el)
 728                                           (if (eq (car el) 'must)
 729                                               (concat "'" (cdr el))
 730                                             (cdr el)))
 731                                         pass1
 732                                         " ")
 733                              ")"))
 734          (cons 'may (concat "[" (mapconcat 'cdr pass1 " ") "]")))))
 735     ((consp value)
 736      (let ((p value)
 737            newlist
 738            use-list*
 739            anynil)
 740        (while (consp p)
 741          (let ((q.txt (desktop-internal-v2s (car p))))
 742            (or anynil (setq anynil (null (car q.txt))))
 743            (setq newlist (cons q.txt newlist)))
 744          (setq p (cdr p)))
 745        (if p
 746            (let ((last (desktop-internal-v2s p)))
 747              (or anynil (setq anynil (null (car last))))
 748              (or anynil
 749                  (setq newlist (cons '(must . ".") newlist)))
 750              (setq use-list* t)
 751              (setq newlist (cons last newlist))))
 752        (setq newlist (nreverse newlist))
 753        (if anynil
 754            (cons nil
 755                  (concat (if use-list* "(desktop-list* "  "(list ")
 756                          (mapconcat (lambda (el)
 757                                       (if (eq (car el) 'must)
 758                                           (concat "'" (cdr el))
 759                                         (cdr el)))
 760                                     newlist
 761                                     " ")
 762                          ")"))
 763          (cons 'must
 764                (concat "(" (mapconcat 'cdr newlist " ") ")")))))
 765     ((subrp value)
 766      (cons nil (concat "(symbol-function '"
 767                        (substring (prin1-to-string value) 7 -1)
 768                        ")")))
 769     ((markerp value)
 770      (let ((pos (prin1-to-string (marker-position value)))
 771            (buf (prin1-to-string (buffer-name (marker-buffer value)))))
 772        (cons nil (concat "(let ((mk (make-marker)))"
 773                          " (add-hook 'desktop-delay-hook"
 774                          " (list 'lambda '() (list 'set-marker mk "
 775                          pos " (get-buffer " buf ")))) mk)"))))
 776     (t                                   ; save as text
 777      (cons 'may "\"Unprintable entity\""))))
 778
 779 ;; ----------------------------------------------------------------------------
 780 (defun desktop-value-to-string (value)
 781   "Convert VALUE to a string that when read evaluates to the same value.
 782 Not all types of values are supported."
 783   (let* ((print-escape-newlines t)
 784          (float-output-format nil)
 785          (quote.txt (desktop-internal-v2s value))
 786          (quote (car quote.txt))
 787          (txt (cdr quote.txt)))
 788     (if (eq quote 'must)
 789         (concat "'" txt)
 790       txt)))
 791
 792 ;; ----------------------------------------------------------------------------
 793 (defun desktop-outvar (varspec)
 794   "Output a setq statement for variable VAR to the desktop file.
 795 The argument VARSPEC may be the variable name VAR (a symbol),
 796 or a cons cell of the form (VAR . MAX-SIZE),
 797 which means to truncate VAR's value to at most MAX-SIZE elements
 798 \(if the value is a list) before saving the value."
 799   (let (var size)
 800     (if (consp varspec)
 801         (setq var (car varspec) size (cdr varspec))
 802       (setq var varspec))
 803     (when (boundp var)
 804       (when (and (integerp size)
 805                  (> size 0)
 806                  (listp (eval var)))
 807         (desktop-truncate (eval var) size))
 808       (insert "(setq "
 809               (symbol-name var)
 810               " "
 811               (desktop-value-to-string (symbol-value var))
 812               ")\n"))))
 813
 814 ;; ----------------------------------------------------------------------------
 815 (defun desktop-save-buffer-p (filename bufname mode &rest dummy)
 816   "Return t if buffer should have its state saved in the desktop file.
 817 FILENAME is the visited file name, BUFNAME is the buffer name, and
 818 MODE is the major mode.
 819 \n\(fn FILENAME BUFNAME MODE)"
 820   (let ((case-fold-search nil)
 821         dired-skip)
 822     (and (not (and (stringp desktop-buffers-not-to-save)
 823                    (not filename)
 824                    (string-match desktop-buffers-not-to-save bufname)))
 825          (not (memq mode desktop-modes-not-to-save))
 826          ;; FIXME this is broken if desktop-files-not-to-save is nil.
 827          (or (and filename
 828                   (stringp desktop-files-not-to-save)
 829                   (not (string-match desktop-files-not-to-save filename)))
 830              (and (eq mode 'dired-mode)
 831                   (with-current-buffer bufname
 832                     (not (setq dired-skip
 833                                (string-match desktop-files-not-to-save
 834                                              default-directory)))))
 835              (and (null filename)
 836                   (null dired-skip)     ; bug#5755
 837                   (with-current-buffer bufname desktop-save-buffer))))))
 838
 839 ;; ----------------------------------------------------------------------------
 840 (defun desktop-file-name (filename dirname)
 841   "Convert FILENAME to format specified in `desktop-file-name-format'.
 842 DIRNAME must be the directory in which the desktop file will be saved."
 843   (cond
 844     ((not filename) nil)
 845     ((eq desktop-file-name-format 'tilde)
 846      (let ((relative-name (file-relative-name (expand-file-name filename) "~")))
 847        (cond
 848          ((file-name-absolute-p relative-name) relative-name)
 849          ((string= "./" relative-name) "~/")
 850          ((string= "." relative-name) "~")
 851          (t (concat "~/" relative-name)))))
 852     ((eq desktop-file-name-format 'local) (file-relative-name filename dirname))
 853     (t (expand-file-name filename))))
 854
 855
 856 ;; ----------------------------------------------------------------------------
 857 ;;;###autoload
 858 (defun desktop-save (dirname &optional release)
 859   "Save the desktop in a desktop file.
 860 Parameter DIRNAME specifies where to save the desktop file.
 861 Optional parameter RELEASE says whether we're done with this desktop.
 862 See also `desktop-base-file-name'."
 863   (interactive "DDirectory to save desktop file in: ")
 864   (setq desktop-dirname (file-name-as-directory (expand-file-name dirname)))
 865   (save-excursion
 866     (let ((eager desktop-restore-eager)
 867           (new-modtime (nth 5 (file-attributes (desktop-full-file-name)))))
 868       (when
 869           (or (not new-modtime)         ; nothing to overwrite
 870               (equal desktop-file-modtime new-modtime)
 871               (yes-or-no-p (if desktop-file-modtime
 872                                (if (> (float-time new-modtime) (float-time desktop-file-modtime))
 873                                    "Desktop file is more recent than the one loaded.  Save anyway? "
 874                                  "Desktop file isn't the one loaded.  Overwrite it? ")
 875                              "Current desktop was not loaded from a file.  Overwrite this desktop file? "))
 876               (unless release (error "Desktop file conflict")))
 877
 878         ;; If we're done with it, release the lock.
 879         ;; Otherwise, claim it if it's unclaimed or if we created it.
 880         (if release
 881             (desktop-release-lock)
 882           (unless (and new-modtime (desktop-owner)) (desktop-claim-lock)))
 883
 884         (with-temp-buffer
 885           (insert
 886            ";; -*- mode: emacs-lisp; coding: emacs-mule; -*-\n"
 887            desktop-header
 888            ";; Created " (current-time-string) "\n"
 889            ";; Desktop file format version " desktop-file-version "\n"
 890            ";; Emacs version " emacs-version "\n")
 891           (save-excursion (run-hooks 'desktop-save-hook))
 892           (goto-char (point-max))
 893           (insert "\n;; Global section:\n")
 894           (mapc (function desktop-outvar) desktop-globals-to-save)
 895           (when (memq 'kill-ring desktop-globals-to-save)
 896             (insert
 897              "(setq kill-ring-yank-pointer (nthcdr "
 898              (int-to-string (- (length kill-ring) (length kill-ring-yank-pointer)))
 899              " kill-ring))\n"))
 900
 901           (insert "\n;; Buffer section -- buffers listed in same order as in buffer list:\n")
 902           (dolist (l (mapcar 'desktop-buffer-info (buffer-list)))
 903             (let ((base (pop l)))
 904               (when (apply 'desktop-save-buffer-p l)
 905                 (insert "("
 906                         (if (or (not (integerp eager))
 907                                 (if (zerop eager)
 908                                     nil
 909                                   (setq eager (1- eager))))
 910                             "desktop-create-buffer"
 911                           "desktop-append-buffer-args")
 912                         " "
 913                         desktop-file-version)
 914                 ;; If there's a non-empty base name, we save it instead of the buffer name
 915                 (when (and base (not (string= base "")))
 916                   (setcar (nthcdr 1 l) base))
 917                 (dolist (e l)
 918                   (insert "\n  " (desktop-value-to-string e)))
 919                 (insert ")\n\n"))))
 920
 921           (setq default-directory desktop-dirname)
 922           (let ((coding-system-for-write 'emacs-mule))
 923             (write-region (point-min) (point-max) (desktop-full-file-name) nil 'nomessage))
 924           ;; We remember when it was modified (which is presumably just now).
 925           (setq desktop-file-modtime (nth 5 (file-attributes (desktop-full-file-name)))))))))
 926
 927 ;; ----------------------------------------------------------------------------
 928 ;;;###autoload
 929 (defun desktop-remove ()
 930   "Delete desktop file in `desktop-dirname'.
 931 This function also sets `desktop-dirname' to nil."
 932   (interactive)
 933   (when desktop-dirname
 934     (let ((filename (desktop-full-file-name)))
 935       (setq desktop-dirname nil)
 936       (when (file-exists-p filename)
 937         (delete-file filename)))))
 938
 939 (defvar desktop-buffer-args-list nil
 940   "List of args for `desktop-create-buffer'.")
 941
 942 (defvar desktop-lazy-timer nil)
 943
 944 ;; ----------------------------------------------------------------------------
 945 ;;;###autoload
 946 (defun desktop-read (&optional dirname)
 947   "Read and process the desktop file in directory DIRNAME.
 948 Look for a desktop file in DIRNAME, or if DIRNAME is omitted, look in
 949 directories listed in `desktop-path'.  If a desktop file is found, it
 950 is processed and `desktop-after-read-hook' is run.  If no desktop file
 951 is found, clear the desktop and run `desktop-no-desktop-file-hook'.
 952 This function is a no-op when Emacs is running in batch mode.
 953 It returns t if a desktop file was loaded, nil otherwise."
 954   (interactive)
 955   (unless noninteractive
 956     (setq desktop-dirname
 957           (file-name-as-directory
 958            (expand-file-name
 959             (or
 960              ;; If DIRNAME is specified, use it.
 961              (and (< 0 (length dirname)) dirname)
 962              ;; Otherwise search desktop file in desktop-path.
 963              (let ((dirs desktop-path))
 964                (while (and dirs
 965                            (not (file-exists-p
 966                                  (desktop-full-file-name (car dirs)))))
 967                  (setq dirs (cdr dirs)))
 968                (and dirs (car dirs)))
 969              ;; If not found and `desktop-path' is non-nil, use its first element.
 970              (and desktop-path (car desktop-path))
 971              ;; Default: Home directory.
 972              "~"))))
 973     (if (file-exists-p (desktop-full-file-name))
 974         ;; Desktop file found, but is it already in use?
 975         (let ((desktop-first-buffer nil)
 976               (desktop-buffer-ok-count 0)
 977               (desktop-buffer-fail-count 0)
 978               (owner (desktop-owner))
 979               ;; Avoid desktop saving during evaluation of desktop buffer.
 980               (desktop-save nil))
 981           (if (and owner
 982                    (memq desktop-load-locked-desktop '(nil ask))
 983                    (or (null desktop-load-locked-desktop)
 984                        (not (y-or-n-p (format "Warning: desktop file appears to be in use by PID %s.\n\
 985 Using it may cause conflicts.  Use it anyway? " owner)))))
 986               (let ((default-directory desktop-dirname))
 987                 (setq desktop-dirname nil)
 988                 (run-hooks 'desktop-not-loaded-hook)
 989                 (unless desktop-dirname
 990                   (message "Desktop file in use; not loaded.")))
 991             (desktop-lazy-abort)
 992             ;; Evaluate desktop buffer and remember when it was modified.
 993             (load (desktop-full-file-name) t t t)
 994             (setq desktop-file-modtime (nth 5 (file-attributes (desktop-full-file-name))))
 995             ;; If it wasn't already, mark it as in-use, to bother other
 996             ;; desktop instances.
 997             (unless owner
 998               (condition-case nil
 999                   (desktop-claim-lock)
1000                 (file-error (message "Couldn't record use of desktop file")
1001                             (sit-for 1))))
1002
1003             ;; `desktop-create-buffer' puts buffers at end of the buffer list.
1004             ;; We want buffers existing prior to evaluating the desktop (and
1005             ;; not reused) to be placed at the end of the buffer list, so we
1006             ;; move them here.
1007             (mapc 'bury-buffer
1008                   (nreverse (cdr (memq desktop-first-buffer (nreverse (buffer-list))))))
1009             (switch-to-buffer (car (buffer-list)))
1010             (run-hooks 'desktop-delay-hook)
1011             (setq desktop-delay-hook nil)
1012             (run-hooks 'desktop-after-read-hook)
1013             (message "Desktop: %d buffer%s restored%s%s."
1014                      desktop-buffer-ok-count
1015                      (if (= 1 desktop-buffer-ok-count) "" "s")
1016                      (if (< 0 desktop-buffer-fail-count)
1017                          (format ", %d failed to restore" desktop-buffer-fail-count)
1018                        "")
1019                      (if desktop-buffer-args-list
1020                          (format ", %d to restore lazily"
1021                                  (length desktop-buffer-args-list))
1022                        ""))
1023             t))
1024       ;; No desktop file found.
1025       (desktop-clear)
1026       (let ((default-directory desktop-dirname))
1027         (run-hooks 'desktop-no-desktop-file-hook))
1028       (message "No desktop file.")
1029       nil)))
1030
1031 ;; ----------------------------------------------------------------------------
1032 ;; Maintained for backward compatibility
1033 ;;;###autoload
1034 (defun desktop-load-default ()
1035   "Load the `default' start-up library manually.
1036 Also inhibit further loading of it."
1037   (unless inhibit-default-init          ; safety check
1038     (load "default" t t)
1039     (setq inhibit-default-init t)))
1040 (make-obsolete 'desktop-load-default
1041                'desktop-save-mode "22.1")
1042
1043 ;; ----------------------------------------------------------------------------
1044 ;;;###autoload
1045 (defun desktop-change-dir (dirname)
1046   "Change to desktop saved in DIRNAME.
1047 Kill the desktop as specified by variables `desktop-save-mode' and
1048 `desktop-save', then clear the desktop and load the desktop file in
1049 directory DIRNAME."
1050   (interactive "DChange to directory: ")
1051   (setq dirname (file-name-as-directory (expand-file-name dirname desktop-dirname)))
1052   (desktop-kill)
1053   (desktop-clear)
1054   (desktop-read dirname))
1055
1056 ;; ----------------------------------------------------------------------------
1057 ;;;###autoload
1058 (defun desktop-save-in-desktop-dir ()
1059   "Save the desktop in directory `desktop-dirname'."
1060   (interactive)
1061   (if desktop-dirname
1062       (desktop-save desktop-dirname)
1063     (call-interactively 'desktop-save))
1064   (message "Desktop saved in %s" (abbreviate-file-name desktop-dirname)))
1065
1066 ;; ----------------------------------------------------------------------------
1067 ;;;###autoload
1068 (defun desktop-revert ()
1069   "Revert to the last loaded desktop."
1070   (interactive)
1071   (unless desktop-dirname
1072     (error "Unknown desktop directory"))
1073   (unless (file-exists-p (desktop-full-file-name))
1074     (error "No desktop file found"))
1075   (desktop-clear)
1076   (desktop-read desktop-dirname))
1077
1078 (defvar desktop-buffer-major-mode)
1079 (defvar desktop-buffer-locals)
1080 ;; ----------------------------------------------------------------------------
1081 (defun desktop-restore-file-buffer (desktop-buffer-file-name
1082                                     desktop-buffer-name
1083                                     desktop-buffer-misc)
1084   "Restore a file buffer."
1085   (when desktop-buffer-file-name
1086     (if (or (file-exists-p desktop-buffer-file-name)
1087             (let ((msg (format "Desktop: File \"%s\" no longer exists."
1088                                desktop-buffer-file-name)))
1089               (if desktop-missing-file-warning
1090                   (y-or-n-p (concat msg " Re-create buffer? "))
1091                 (message "%s" msg)
1092                 nil)))
1093         (let* ((auto-insert nil) ; Disable auto insertion
1094                (coding-system-for-read
1095                 (or coding-system-for-read
1096                     (cdr (assq 'buffer-file-coding-system
1097                                desktop-buffer-locals))))
1098                (buf (find-file-noselect desktop-buffer-file-name)))
1099           (condition-case nil
1100               (switch-to-buffer buf)
1101             (error (pop-to-buffer buf)))
1102           (and (not (eq major-mode desktop-buffer-major-mode))
1103                (functionp desktop-buffer-major-mode)
1104                (funcall desktop-buffer-major-mode))
1105           buf)
1106       nil)))
1107
1108 (defun desktop-load-file (function)
1109   "Load the file where auto loaded FUNCTION is defined."
1110   (when function
1111     (let ((fcell (and (fboundp function) (symbol-function function))))
1112       (when (and (listp fcell)
1113                  (eq 'autoload (car fcell)))
1114         (load (cadr fcell))))))
1115
1116 ;; ----------------------------------------------------------------------------
1117 ;; Create a buffer, load its file, set its mode, ...;
1118 ;; called from Desktop file only.
1119
1120 ;; Just to silence the byte compiler.
1121
1122 (defvar desktop-first-buffer)          ; Dynamically bound in `desktop-read'
1123
1124 ;; Bound locally in `desktop-read'.
1125 (defvar desktop-buffer-ok-count)
1126 (defvar desktop-buffer-fail-count)
1127
1128 (defun desktop-create-buffer
1129   (desktop-file-version
1130    desktop-buffer-file-name
1131    desktop-buffer-name
1132    desktop-buffer-major-mode
1133    desktop-buffer-minor-modes
1134    desktop-buffer-point
1135    desktop-buffer-mark
1136    desktop-buffer-read-only
1137    desktop-buffer-misc
1138    &optional
1139    desktop-buffer-locals)
1140   ;; To make desktop files with relative file names possible, we cannot
1141   ;; allow `default-directory' to change. Therefore we save current buffer.
1142   (save-current-buffer
1143     ;; Give major mode module a chance to add a handler.
1144     (desktop-load-file desktop-buffer-major-mode)
1145     (let ((buffer-list (buffer-list))
1146           (result
1147            (condition-case-no-debug err
1148                (funcall (or (cdr (assq desktop-buffer-major-mode
1149                                        desktop-buffer-mode-handlers))
1150                             'desktop-restore-file-buffer)
1151                         desktop-buffer-file-name
1152                         desktop-buffer-name
1153                         desktop-buffer-misc)
1154              (error
1155               (message "Desktop: Can't load buffer %s: %s"
1156                        desktop-buffer-name
1157                        (error-message-string err))
1158               (when desktop-missing-file-warning (sit-for 1))
1159               nil))))
1160       (if (bufferp result)
1161           (setq desktop-buffer-ok-count (1+ desktop-buffer-ok-count))
1162         (setq desktop-buffer-fail-count (1+ desktop-buffer-fail-count))
1163         (setq result nil))
1164       ;; Restore buffer list order with new buffer at end. Don't change
1165       ;; the order for old desktop files (old desktop module behaviour).
1166       (unless (< desktop-file-version 206)
1167         (mapc 'bury-buffer buffer-list)
1168         (when result (bury-buffer result)))
1169       (when result
1170         (unless (or desktop-first-buffer (< desktop-file-version 206))
1171           (setq desktop-first-buffer result))
1172         (set-buffer result)
1173         (unless (equal (buffer-name) desktop-buffer-name)
1174           (rename-buffer desktop-buffer-name t))
1175         ;; minor modes
1176         (cond ((equal '(t) desktop-buffer-minor-modes) ; backwards compatible
1177                (auto-fill-mode 1))
1178               ((equal '(nil) desktop-buffer-minor-modes) ; backwards compatible
1179                (auto-fill-mode 0))
1180               (t
1181                (dolist (minor-mode desktop-buffer-minor-modes)
1182                  ;; Give minor mode module a chance to add a handler.
1183                  (desktop-load-file minor-mode)
1184                  (let ((handler (cdr (assq minor-mode desktop-minor-mode-handlers))))
1185                    (if handler
1186                        (funcall handler desktop-buffer-locals)
1187                      (when (functionp minor-mode)
1188                        (funcall minor-mode 1)))))))
1189         ;; Even though point and mark are non-nil when written by
1190         ;; `desktop-save', they may be modified by handlers wanting to set
1191         ;; point or mark themselves.
1192         (when desktop-buffer-point
1193           (goto-char
1194             (condition-case err
1195                 ;; Evaluate point.  Thus point can be something like
1196                 ;; '(search-forward ...
1197                 (eval desktop-buffer-point)
1198               (error (message "%s" (error-message-string err)) 1))))
1199         (when desktop-buffer-mark
1200           (if (consp desktop-buffer-mark)
1201               (progn
1202                 (set-mark (car desktop-buffer-mark))
1203                 (setq mark-active (car (cdr desktop-buffer-mark))))
1204             (set-mark desktop-buffer-mark)))
1205         ;; Never override file system if the file really is read-only marked.
1206         (when desktop-buffer-read-only (setq buffer-read-only desktop-buffer-read-only))
1207         (while desktop-buffer-locals
1208           (let ((this (car desktop-buffer-locals)))
1209             (if (consp this)
1210                 ;; an entry of this form `(symbol . value)'
1211                 (progn
1212                   (make-local-variable (car this))
1213                   (set (car this) (cdr this)))
1214               ;; an entry of the form `symbol'
1215               (make-local-variable this)
1216               (makunbound this)))
1217           (setq desktop-buffer-locals (cdr desktop-buffer-locals)))))))
1218
1219 ;; ----------------------------------------------------------------------------
1220 ;; Backward compatibility -- update parameters to 205 standards.
1221 (defun desktop-buffer (desktop-buffer-file-name desktop-buffer-name
1222                        desktop-buffer-major-mode
1223                        mim pt mk ro tl fc cfs cr desktop-buffer-misc)
1224   (desktop-create-buffer 205 desktop-buffer-file-name desktop-buffer-name
1225                          desktop-buffer-major-mode (cdr mim) pt mk ro
1226                          desktop-buffer-misc
1227                          (list (cons 'truncate-lines tl)
1228                                (cons 'fill-column fc)
1229                                (cons 'case-fold-search cfs)
1230                                (cons 'case-replace cr)
1231                                (cons 'overwrite-mode (car mim)))))
1232
1233 (defun desktop-append-buffer-args (&rest args)
1234   "Append ARGS at end of `desktop-buffer-args-list'.
1235 ARGS must be an argument list for `desktop-create-buffer'."
1236   (setq desktop-buffer-args-list (nconc desktop-buffer-args-list (list args)))
1237   (unless desktop-lazy-timer
1238     (setq desktop-lazy-timer
1239           (run-with-idle-timer desktop-lazy-idle-delay t 'desktop-idle-create-buffers))))
1240
1241 (defun desktop-lazy-create-buffer ()
1242   "Pop args from `desktop-buffer-args-list', create buffer and bury it."
1243   (when desktop-buffer-args-list
1244     (let* ((remaining (length desktop-buffer-args-list))
1245            (args (pop desktop-buffer-args-list))
1246            (buffer-name (nth 2 args))
1247            (msg (format "Desktop lazily opening %s (%s remaining)..."
1248                             buffer-name remaining)))
1249       (when desktop-lazy-verbose
1250         (message "%s" msg))
1251       (let ((desktop-first-buffer nil)
1252             (desktop-buffer-ok-count 0)
1253             (desktop-buffer-fail-count 0))
1254         (apply 'desktop-create-buffer args)
1255         (run-hooks 'desktop-delay-hook)
1256         (setq desktop-delay-hook nil)
1257         (bury-buffer (get-buffer buffer-name))
1258         (when desktop-lazy-verbose
1259           (message "%s%s" msg (if (> desktop-buffer-ok-count 0) "done" "failed")))))))
1260
1261 (defun desktop-idle-create-buffers ()
1262   "Create buffers until the user does something, then stop.
1263 If there are no buffers left to create, kill the timer."
1264   (let ((repeat 1))
1265     (while (and repeat desktop-buffer-args-list)
1266       (save-window-excursion
1267         (desktop-lazy-create-buffer))
1268       (setq repeat (sit-for 0.2))
1269     (unless desktop-buffer-args-list
1270       (cancel-timer desktop-lazy-timer)
1271       (setq desktop-lazy-timer nil)
1272       (message "Lazy desktop load complete")
1273       (sit-for 3)
1274       (message "")))))
1275
1276 (defun desktop-lazy-complete ()
1277   "Run the desktop load to completion."
1278   (interactive)
1279   (let ((desktop-lazy-verbose t))
1280     (while desktop-buffer-args-list
1281       (save-window-excursion
1282         (desktop-lazy-create-buffer)))
1283     (message "Lazy desktop load complete")))
1284
1285 (defun desktop-lazy-abort ()
1286   "Abort lazy loading of the desktop."
1287   (interactive)
1288   (when desktop-lazy-timer
1289     (cancel-timer desktop-lazy-timer)
1290     (setq desktop-lazy-timer nil))
1291   (when desktop-buffer-args-list
1292     (setq desktop-buffer-args-list nil)
1293     (when (called-interactively-p 'interactive)
1294       (message "Lazy desktop load aborted"))))
1295
1296 ;; ----------------------------------------------------------------------------
1297 ;; When `desktop-save-mode' is non-nil and "--no-desktop" is not specified on the
1298 ;; command line, we do the rest of what it takes to use desktop, but do it
1299 ;; after finishing loading the init file.
1300 ;; We cannot use `command-switch-alist' to process "--no-desktop" because these
1301 ;; functions are processed after `after-init-hook'.
1302 (add-hook
1303   'after-init-hook
1304   (lambda ()
1305     (let ((key "--no-desktop"))
1306       (when (member key command-line-args)
1307         (setq command-line-args (delete key command-line-args))
1308         (setq desktop-save-mode nil)))
1309     (when desktop-save-mode
1310       (desktop-read)
1311       (setq inhibit-startup-screen t))))
1312
1313 (provide 'desktop)
1314
1315 ;; arch-tag: 221907c3-1771-4fd3-9c2e-c6f700c6ede9
1316 ;;; desktop.el ends here