X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/ed2f7fc80bd67fce14197537a0ff89a778831e20..aef88a00d364bbb208acff2d9b66b2a1eb6cf8f5:/lisp/desktop.el

diff --git a/lisp/desktop.el b/lisp/desktop.el
index e60cab8bce..a042828e19 100644
--- a/lisp/desktop.el
+++ b/lisp/desktop.el
@@ -1,16 +1,17 @@
 ;;; desktop.el --- save partial status of Emacs when killed
 
-;; Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 1995, 1997, 2000, 2001, 2002, 2003,
+;;   2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
 
 ;; Author: Morten Welinder <terra@diku.dk>
-;; Keywords: customization
+;; Keywords: convenience
 ;; Favourite-brand-of-beer: None, I hate beer.
 
 ;; This file is part of GNU Emacs.
 
 ;; GNU Emacs is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
-;; the Free Software Foundation; either version 2, or (at your option)
+;; the Free Software Foundation; either version 3, or (at your option)
 ;; any later version.
 
 ;; GNU Emacs is distributed in the hope that it will be useful,
@@ -20,8 +21,8 @@
 
 ;; You should have received a copy of the GNU General Public License
 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
 
@@ -35,41 +36,80 @@
 ;;		- buffer-read-only
 ;;		- some local variables
 
-;; To use this, first put these three lines in the bottom of your .emacs
-;; file (the later the better):
+;; To use this, use customize to turn on desktop-save-mode or add the
+;; following line somewhere in your .emacs file:
 ;;
-;;	(load "desktop")
-;;	(desktop-load-default)
-;;	(desktop-read)
+;;	(desktop-save-mode 1)
 ;;
-;; Between the second and the third line you may wish to add something that
-;; updates the variables `desktop-globals-to-save' and/or
-;; `desktop-locals-to-save'.  If for instance you want to save the local
-;; variable `foobar' for every buffer in which it is local, you could add
-;; the line
+;; For further usage information, look at the section
+;; "Saving Emacs Sessions" in the GNU Emacs Manual.
+
+;; When the desktop module is loaded, the function `desktop-kill' is
+;; added to the `kill-emacs-hook'.  This function is responsible for
+;; saving the desktop when Emacs is killed.  Furthermore an anonymous
+;; function is added to the `after-init-hook'.  This function is
+;; responsible for loading the desktop when Emacs is started.
+
+;; Special handling.
+;; -----------------
+;; Variables `desktop-buffer-mode-handlers' and `desktop-minor-mode-handlers'
+;; are supplied to handle special major and minor modes respectively.
+;; `desktop-buffer-mode-handlers' is an alist of major mode specific functions
+;; to restore a desktop buffer.  Elements must have the form
 ;;
-;;	(setq desktop-locals-to-save (cons 'foobar desktop-locals-to-save))
+;;    (MAJOR-MODE . RESTORE-BUFFER-FUNCTION).
 ;;
-;; To avoid saving excessive amounts of data you may also wish to add
-;; something like the following
+;; Functions listed are called by `desktop-create-buffer' when `desktop-read'
+;; evaluates the desktop file.  Buffers with a major mode not specified here,
+;; are restored by the default handler `desktop-restore-file-buffer'.
+;; `desktop-minor-mode-handlers' is an alist of functions to restore
+;; non-standard minor modes.  Elements must have the form
 ;;
-;;	(add-hook 'kill-emacs-hook
-;;		  '(lambda ()
-;;		     (desktop-truncate search-ring 3)
-;;		     (desktop-truncate regexp-search-ring 3)))
+;;    (MINOR-MODE . RESTORE-FUNCTION).
 ;;
-;; which will make sure that no more than three search items are saved.  You
-;; must place this line *after* the (load "desktop") line.  See also the
-;; variable desktop-save-hook.
-
-;; Start Emacs in the root directory of your "project". The desktop saver
-;; is inactive by default.  You activate it by M-x desktop-save RET.  When
-;; you exit the next time the above data will be saved.  This ensures that
-;; all the files you were editing will be reloaded the next time you start
-;; Emacs from the same directory and that points will be set where you
-;; left them.  If you save a desktop file in your home directory it will
-;; act as a default desktop when you start Emacs from a directory that
-;; doesn't have its own.  I never do this, but you may want to.
+;; Functions are called by `desktop-create-buffer' to restore minor modes.
+;; Minor modes not specified here, are restored by the standard minor mode
+;; function.  If you write a module that defines a major or minor mode that
+;; needs a special handler, then place code like
+
+;;    (defun foo-restore-desktop-buffer
+;;    ...
+;;    (add-to-list 'desktop-buffer-mode-handlers
+;;                 '(foo-mode . foo-restore-desktop-buffer))
+
+;; or
+
+;;    (defun bar-desktop-restore
+;;    ...
+;;    (add-to-list 'desktop-minor-mode-handlers
+;;                 '(bar-mode . bar-desktop-restore))
+
+;; in the module itself, and make shure that the mode function is
+;; autoloaded.  See the docstrings of `desktop-buffer-mode-handlers' and
+;; `desktop-minor-mode-handlers' for more info.
+
+;; Minor modes.
+;; ------------
+;; Conventional minor modes (see node "Minor Mode Conventions" in the elisp
+;; manual) are handled in the following way:
+;; When `desktop-save' saves the state of a buffer to the desktop file, it
+;; saves as `desktop-minor-modes' the list of names of those variables in
+;; `minor-mode-alist' that have a non-nil value.
+;; When `desktop-create' restores the buffer, each of the symbols in
+;; `desktop-minor-modes' is called as function with parameter 1.
+;; The variables `desktop-minor-mode-table' and `desktop-minor-mode-handlers'
+;; are used to handle non-conventional minor modes.  `desktop-save' uses
+;; `desktop-minor-mode-table' to map minor mode variables to minor mode
+;; functions before writing `desktop-minor-modes'.  If a minor mode has a
+;; variable name that is different form its function name, an entry
+
+;;    (NAME RESTORE-FUNCTION)
+
+;; should be added to `desktop-minor-mode-table'.  If a minor mode should not
+;; be restored, RESTORE-FUNCTION should be set to nil.  `desktop-create' uses
+;; `desktop-minor-mode-handlers' to lookup minor modes that needs a restore
+;; function different from the usual minor mode function.
+;; ---------------------------------------------------------------------------
 
 ;; By the way: don't use desktop.el to customize Emacs -- the file .emacs
 ;; in your home directory is used for that.  Saving global default values
@@ -92,93 +132,400 @@
 ;; Save window configuration.
 ;; Recognize more minor modes.
 ;; Save mark rings.
-;; Start-up with buffer-menu???
 
 ;;; Code:
 
-;; Make the compilation more silent
-(eval-when-compile
-  ;; We use functions from these modules
-  ;; We can't (require 'mh-e) since that wants to load something.
-  (mapcar 'require '(info dired reporter)))
+(defvar desktop-file-version "206"
+  "Version number of desktop file format.
+Written into the desktop file and used at desktop read to provide
+backward compatibility.")
+
 ;; ----------------------------------------------------------------------------
 ;; USER OPTIONS -- settings you might want to play with.
 ;; ----------------------------------------------------------------------------
-(defconst desktop-basefilename
-  (if (or (eq system-type 'ms-dos) (eq system-type 'windows-nt))
-      "emacs.dsk" ; Ms-Dos does not support multiple dots in file name
-    ".emacs.desktop")
-  "File for Emacs desktop, not including the directory name.")
-
-(defvar desktop-missing-file-warning t
-  "*If non-nil then desktop warns when a file no longer exists.
-Otherwise it simply ignores that file.")
-
-(defvar desktop-globals-to-save
-  (list 'desktop-missing-file-warning
-	;; Feature: saving kill-ring implies saving kill-ring-yank-pointer
-	;; 'kill-ring
-	'tags-file-name
-	'tags-table-list
-	'search-ring
-	'regexp-search-ring
-	'register-alist
-	;; 'desktop-globals-to-save	; Itself!
-	)
-  "List of global variables to save when killing Emacs.
-An element may be variable name (a symbol)
-or a cons cell of the form  (VAR . MAX-SIZE),
-which means to truncate VAR's value to at most MAX-SIZE elements
-\(if the value is a list) before saving the value.")
-
-(defvar desktop-locals-to-save
-  (list 'desktop-locals-to-save		; Itself!  Think it over.
-        'truncate-lines
-	'case-fold-search
-	'case-replace
-	'fill-column
-	'overwrite-mode
-	'change-log-default-name
-	'line-number-mode
-	)
+
+(defgroup desktop nil
+  "Save status of Emacs when you exit."
+  :group 'frames)
+
+;;;###autoload
+(define-minor-mode desktop-save-mode
+  "Toggle desktop saving mode.
+With numeric ARG, turn desktop saving on if ARG is positive, off
+otherwise.  If desktop saving is turned on, the state of Emacs is
+saved from one session to another.  See variable `desktop-save'
+and function `desktop-read' for details."
+  :global t
+  :group 'desktop)
+
+;; Maintained for backward compatibility
+(define-obsolete-variable-alias 'desktop-enable
+                                'desktop-save-mode "22.1")
+
+(defun desktop-save-mode-off ()
+  "Disable `desktop-save-mode'.  Provided for use in hooks."
+  (desktop-save-mode 0))
+
+(defcustom desktop-save 'ask-if-new
+  "*Specifies whether the desktop should be saved when it is killed.
+A desktop is killed when the user changes desktop or quits Emacs.
+Possible values are:
+   t             -- always save.
+   ask           -- always ask.
+   ask-if-new    -- ask if no desktop file exists, otherwise just save.
+   ask-if-exists -- ask if desktop file exists, otherwise don't save.
+   if-exists     -- save if desktop file exists, otherwise don't save.
+   nil           -- never save.
+The desktop is never saved when `desktop-save-mode' is nil.
+The variables `desktop-dirname' and `desktop-base-file-name'
+determine where the desktop is saved."
+  :type
+  '(choice
+    (const :tag "Always save" t)
+    (const :tag "Always ask" ask)
+    (const :tag "Ask if desktop file is new, else do save" ask-if-new)
+    (const :tag "Ask if desktop file exists, else don't save" ask-if-exists)
+    (const :tag "Save if desktop file exists, else don't" if-exists)
+    (const :tag "Never save" nil))
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-load-locked-desktop 'ask
+  "Specifies whether the desktop should be loaded if locked.
+Possible values are:
+   t    -- load anyway.
+   nil  -- don't load.
+   ask  -- ask the user.
+If the value is nil, or `ask' and the user chooses not to load the desktop,
+the normal hook `desktop-not-loaded-hook' is run."
+  :type
+  '(choice
+    (const :tag "Load anyway" t)
+    (const :tag "Don't load" nil)
+    (const :tag "Ask the user" ask))
+  :group 'desktop
+  :version "22.2")
+
+(defcustom desktop-base-file-name
+  (convert-standard-filename ".emacs.desktop")
+  "Name of file for Emacs desktop, excluding the directory part."
+  :type 'file
+  :group 'desktop)
+(define-obsolete-variable-alias 'desktop-basefilename
+                                'desktop-base-file-name "22.1")
+
+(defcustom desktop-base-lock-name
+  (convert-standard-filename ".emacs.desktop.lock")
+  "Name of lock file for Emacs desktop, excluding the directory part."
+  :type 'file
+  :group 'desktop
+  :version "22.2")
+
+(defcustom desktop-path '("." "~")
+  "List of directories to search for the desktop file.
+The base name of the file is specified in `desktop-base-file-name'."
+  :type '(repeat directory)
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-missing-file-warning nil
+  "If non-nil, offer to recreate the buffer of a deleted file.
+Also pause for a moment to display message about errors signaled in
+`desktop-buffer-mode-handlers'.
+
+If nil, just print error messages in the message buffer."
+  :type 'boolean
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-no-desktop-file-hook nil
+  "Normal hook run when `desktop-read' can't find a desktop file.
+Run in the directory in which the desktop file was sought.
+May be used to show a dired buffer."
+  :type 'hook
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-not-loaded-hook nil
+  "Normal hook run when the user declines to re-use a desktop file.
+Run in the directory in which the desktop file was found.
+May be used to deal with accidental multiple Emacs jobs."
+  :type 'hook
+  :group 'desktop
+  :options '(desktop-save-mode-off save-buffers-kill-emacs)
+  :version "22.2")
+
+(defcustom desktop-after-read-hook nil
+  "Normal hook run after a successful `desktop-read'.
+May be used to show a buffer list."
+  :type 'hook
+  :group 'desktop
+  :options '(list-buffers)
+  :version "22.1")
+
+(defcustom desktop-save-hook nil
+  "Normal hook run before the desktop is saved in a desktop file.
+Run with the desktop buffer current with only the header present.
+May be used to add to the desktop code or to truncate history lists,
+for example."
+  :type 'hook
+  :group 'desktop)
+
+(defcustom desktop-globals-to-save
+  '(desktop-missing-file-warning
+    tags-file-name
+    tags-table-list
+    search-ring
+    regexp-search-ring
+    register-alist)
+  "List of global variables saved by `desktop-save'.
+An element may be variable name (a symbol) or a cons cell of the form
+\(VAR . MAX-SIZE), which means to truncate VAR's value to at most
+MAX-SIZE elements (if the value is a list) before saving the value.
+Feature: Saving `kill-ring' implies saving `kill-ring-yank-pointer'."
+  :type '(repeat (restricted-sexp :match-alternatives (symbolp consp)))
+  :group 'desktop)
+
+(defcustom desktop-globals-to-clear
+  '(kill-ring
+    kill-ring-yank-pointer
+    search-ring
+    search-ring-yank-pointer
+    regexp-search-ring
+    regexp-search-ring-yank-pointer)
+  "List of global variables that `desktop-clear' will clear.
+An element may be variable name (a symbol) or a cons cell of the form
+\(VAR . FORM).  Symbols are set to nil and for cons cells VAR is set
+to the value obtained by evaluating FORM."
+  :type '(repeat (restricted-sexp :match-alternatives (symbolp consp)))
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-clear-preserve-buffers
+  '("\\*scratch\\*" "\\*Messages\\*" "\\*server\\*" "\\*tramp/.+\\*")
+  "*List of buffers that `desktop-clear' should not delete.
+Each element is a regular expression.  Buffers with a name matched by any of
+these won't be deleted."
+  :type '(repeat string)
+  :group 'desktop)
+
+;;;###autoload
+(defcustom desktop-locals-to-save
+  '(desktop-locals-to-save  ; Itself!  Think it over.
+    truncate-lines
+    case-fold-search
+    case-replace
+    fill-column
+    overwrite-mode
+    change-log-default-name
+    line-number-mode
+    column-number-mode
+    size-indication-mode
+    buffer-file-coding-system
+    indent-tabs-mode
+    tab-width
+    indicate-buffer-boundaries
+    indicate-empty-lines
+    show-trailing-whitespace)
   "List of local variables to save for each buffer.
-The variables are saved only when they really are local.")
-(make-variable-buffer-local 'desktop-locals-to-save)
+The variables are saved only when they really are local.  Conventional minor
+modes are restored automatically; they should not be listed here."
+  :type '(repeat symbol)
+  :group 'desktop)
 
 ;; We skip .log files because they are normally temporary.
 ;;         (ftp) files because they require passwords and whatnot.
-;;         TAGS files to save time (tags-file-name is saved instead).
-(defvar desktop-buffers-not-to-save
- "\\(^nn\\.a[0-9]+\\|\\.log\\|(ftp)\\|^tags\\|^TAGS\\)$"
- "Regexp identifying buffers that are to be excluded from saving.")
+(defcustom desktop-buffers-not-to-save
+  "\\(^nn\\.a[0-9]+\\|\\.log\\|(ftp)\\)$"
+  "Regexp identifying buffers that are to be excluded from saving."
+  :type 'regexp
+  :group 'desktop)
 
-;; Skip ange-ftp files
-(defvar desktop-files-not-to-save
+;; Skip tramp and ange-ftp files
+(defcustom desktop-files-not-to-save
   "^/[^/:]*:"
-  "Regexp identifying files whose buffers are to be excluded from saving.")
-
-(defvar desktop-buffer-handlers
-  '(desktop-buffer-dired
-    desktop-buffer-rmail
-    desktop-buffer-mh
-    desktop-buffer-info
-    desktop-buffer-file)
-  "*List of functions to call in order to create a buffer.
-The functions are called without explicit parameters but may access
-the the major mode as `mam', the file name as `fn', the buffer name as
-`bn', the default directory as `dd'.  If some function returns non-nil
-no further functions are called.  If the function returns t then the
-buffer is considered created.")
-
-(defvar desktop-create-buffer-form "(desktop-create-buffer 205"
-  "Opening of form for creation of new buffers.")
-
-(defvar desktop-save-hook nil
-  "Hook run before saving the desktop to allow you to cut history lists and
-the like shorter.")
+  "Regexp identifying files whose buffers are to be excluded from saving."
+  :type 'regexp
+  :group 'desktop)
+
+;; We skip TAGS files to save time (tags-file-name is saved instead).
+(defcustom desktop-modes-not-to-save
+  '(tags-table-mode)
+  "List of major modes whose buffers should not be saved."
+  :type '(repeat symbol)
+  :group 'desktop)
+
+(defcustom desktop-file-name-format 'absolute
+  "*Format in which desktop file names should be saved.
+Possible values are:
+   absolute -- Absolute file name.
+   tilde    -- Relative to ~.
+   local    -- Relative to directory of desktop file."
+  :type '(choice (const absolute) (const tilde) (const local))
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-restore-eager t
+  "Number of buffers to restore immediately.
+Remaining buffers are restored lazily (when Emacs is idle).
+If value is t, all buffers are restored immediately."
+  :type '(choice (const t) integer)
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-lazy-verbose t
+  "Verbose reporting of lazily created buffers."
+  :type 'boolean
+  :group 'desktop
+  :version "22.1")
+
+(defcustom desktop-lazy-idle-delay 5
+  "Idle delay before starting to create buffers.
+See `desktop-restore-eager'."
+  :type 'integer
+  :group 'desktop
+  :version "22.1")
+
+;;;###autoload
+(defvar desktop-save-buffer nil
+  "When non-nil, save buffer status in desktop file.
+This variable becomes buffer local when set.
+
+If the value is a function, it is called by `desktop-save' with argument
+DESKTOP-DIRNAME to obtain auxiliary information to save in the desktop
+file along with the state of the buffer for which it was called.
+
+When file names are returned, they should be formatted using the call
+\"(desktop-file-name FILE-NAME DESKTOP-DIRNAME)\".
+
+Later, when `desktop-read' evaluates the desktop file, auxiliary information
+is passed as the argument DESKTOP-BUFFER-MISC to functions in
+`desktop-buffer-mode-handlers'.")
+(make-variable-buffer-local 'desktop-save-buffer)
+(make-obsolete-variable 'desktop-buffer-modes-to-save
+                        'desktop-save-buffer "22.1")
+(make-obsolete-variable 'desktop-buffer-misc-functions
+                        'desktop-save-buffer "22.1")
+
+;;;###autoload
+(defvar desktop-buffer-mode-handlers
+  nil
+  "Alist of major mode specific functions to restore a desktop buffer.
+Functions listed are called by `desktop-create-buffer' when `desktop-read'
+evaluates the desktop file.  List elements must have the form
+
+   (MAJOR-MODE . RESTORE-BUFFER-FUNCTION).
+
+Buffers with a major mode not specified here, are restored by the default
+handler `desktop-restore-file-buffer'.
+
+Handlers are called with argument list
+
+   (DESKTOP-BUFFER-FILE-NAME DESKTOP-BUFFER-NAME DESKTOP-BUFFER-MISC)
+
+Furthermore, they may use the following variables:
+
+   desktop-file-version
+   desktop-buffer-major-mode
+   desktop-buffer-minor-modes
+   desktop-buffer-point
+   desktop-buffer-mark
+   desktop-buffer-read-only
+   desktop-buffer-locals
+
+If a handler returns a buffer, then the saved mode settings
+and variable values for that buffer are copied into it.
+
+Modules that define a major mode that needs a special handler should contain
+code like
+
+   (defun foo-restore-desktop-buffer
+   ...
+   (add-to-list 'desktop-buffer-mode-handlers
+                '(foo-mode . foo-restore-desktop-buffer))
+
+Furthermore the major mode function must be autoloaded.")
+
+;;;###autoload
+(put 'desktop-buffer-mode-handlers 'risky-local-variable t)
+(make-obsolete-variable 'desktop-buffer-handlers
+                        'desktop-buffer-mode-handlers "22.1")
+
+(defcustom desktop-minor-mode-table
+  '((auto-fill-function auto-fill-mode)
+    (vc-mode nil)
+    (vc-dired-mode nil))
+  "Table mapping minor mode variables to minor mode functions.
+Each entry has the form (NAME RESTORE-FUNCTION).
+NAME is the name of the buffer-local variable indicating that the minor
+mode is active.  RESTORE-FUNCTION is the function to activate the minor mode.
+RESTORE-FUNCTION nil means don't try to restore the minor mode.
+Only minor modes for which the name of the buffer-local variable
+and the name of the minor mode function are different have to be added to
+this table.  See also `desktop-minor-mode-handlers'."
+  :type 'sexp
+  :group 'desktop)
+
+;;;###autoload
+(defvar desktop-minor-mode-handlers
+  nil
+  "Alist of functions to restore non-standard minor modes.
+Functions are called by `desktop-create-buffer' to restore minor modes.
+List elements must have the form
+
+   (MINOR-MODE . RESTORE-FUNCTION).
+
+Minor modes not specified here, are restored by the standard minor mode
+function.
+
+Handlers are called with argument list
+
+   (DESKTOP-BUFFER-LOCALS)
+
+Furthermore, they may use the following variables:
+
+   desktop-file-version
+   desktop-buffer-file-name
+   desktop-buffer-name
+   desktop-buffer-major-mode
+   desktop-buffer-minor-modes
+   desktop-buffer-point
+   desktop-buffer-mark
+   desktop-buffer-read-only
+   desktop-buffer-misc
+
+When a handler is called, the buffer has been created and the major mode has
+been set, but local variables listed in desktop-buffer-locals has not yet been
+created and set.
+
+Modules that define a minor mode that needs a special handler should contain
+code like
+
+   (defun foo-desktop-restore
+   ...
+   (add-to-list 'desktop-minor-mode-handlers
+                '(foo-mode . foo-desktop-restore))
+
+Furthermore the minor mode function must be autoloaded.
+
+See also `desktop-minor-mode-table'.")
+
+;;;###autoload
+(put 'desktop-minor-mode-handlers 'risky-local-variable t)
+
 ;; ----------------------------------------------------------------------------
 (defvar desktop-dirname nil
-  "The directory in which the current desktop file resides.")
+  "The directory in which the desktop file should be saved.")
+
+(defun desktop-full-file-name (&optional dirname)
+  "Return the full name of the desktop file in DIRNAME.
+DIRNAME omitted or nil means use `desktop-dirname'."
+  (expand-file-name desktop-base-file-name (or dirname desktop-dirname)))
+
+(defun desktop-full-lock-name (&optional dirname)
+  "Return the full name of the desktop lock file in DIRNAME.
+DIRNAME omitted or nil means use `desktop-dirname'."
+  (expand-file-name desktop-base-lock-name (or dirname desktop-dirname)))
 
 (defconst desktop-header
 ";; --------------------------------------------------------------------------
@@ -188,34 +535,106 @@ the like shorter.")
 
 (defvar desktop-delay-hook nil
   "Hooks run after all buffers are loaded; intended for internal use.")
+
+;; ----------------------------------------------------------------------------
+;; Desktop file conflict detection
+(defvar desktop-file-modtime nil
+  "When the desktop file was last modified to the knowledge of this Emacs.
+Used to detect desktop file conflicts.")
+
+(defun desktop-owner (&optional dirname)
+  "Return the PID of the Emacs process that owns the desktop file in DIRNAME.
+Return nil if no desktop file found or no Emacs process is using it.
+DIRNAME omitted or nil means use `desktop-dirname'."
+  (let (owner)
+    (and (file-exists-p (desktop-full-lock-name dirname))
+	 (condition-case nil
+	     (with-temp-buffer
+	       (insert-file-contents-literally (desktop-full-lock-name dirname))
+	       (goto-char (point-min))
+	       (setq owner (read (current-buffer)))
+	       (integerp owner))
+	   (error nil))
+	 owner)))
+
+(defun desktop-claim-lock (&optional dirname)
+  "Record this Emacs process as the owner of the desktop file in DIRNAME.
+DIRNAME omitted or nil means use `desktop-dirname'."
+  (write-region (number-to-string (emacs-pid)) nil
+		(desktop-full-lock-name dirname)))
+
+(defun desktop-release-lock (&optional dirname)
+  "Remove the lock file for the desktop in DIRNAME.
+DIRNAME omitted or nil means use `desktop-dirname'."
+  (let ((file (desktop-full-lock-name dirname)))
+    (when (file-exists-p file) (delete-file file))))
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-truncate (l n)
+(defun desktop-truncate (list n)
   "Truncate LIST to at most N elements destructively."
-  (let ((here (nthcdr (1- n) l)))
-    (if (consp here)
-	(setcdr here nil))))
+  (let ((here (nthcdr (1- n) list)))
+    (when (consp here)
+      (setcdr here nil))))
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-clear () "Empty the Desktop."
+;;;###autoload
+(defun desktop-clear ()
+  "Empty the Desktop.
+This kills all buffers except for internal ones and those with names matched by
+a regular expression in the list `desktop-clear-preserve-buffers'.
+Furthermore, it clears the variables listed in `desktop-globals-to-clear'."
   (interactive)
-  (setq kill-ring nil
-	kill-ring-yank-pointer nil
-	search-ring nil
-	search-ring-yank-pointer nil
-	regexp-search-ring nil
-	regexp-search-ring-yank-pointer nil)
-  (mapcar (function kill-buffer) (buffer-list))
+  (desktop-lazy-abort)
+  (dolist (var desktop-globals-to-clear)
+    (if (symbolp var)
+	(eval `(setq-default ,var nil))
+      (eval `(setq-default ,(car var) ,(cdr var)))))
+  (let ((buffers (buffer-list))
+        (preserve-regexp (concat "^\\("
+                                 (mapconcat (lambda (regexp)
+                                              (concat "\\(" regexp "\\)"))
+                                            desktop-clear-preserve-buffers
+                                            "\\|")
+                                 "\\)$")))
+    (while buffers
+      (let ((bufname (buffer-name (car buffers))))
+         (or
+           (null bufname)
+           (string-match preserve-regexp bufname)
+           ;; Don't kill buffers made for internal purposes.
+           (and (not (equal bufname "")) (eq (aref bufname 0) ?\s))
+           (kill-buffer (car buffers))))
+      (setq buffers (cdr buffers))))
   (delete-other-windows))
+
 ;; ----------------------------------------------------------------------------
 (add-hook 'kill-emacs-hook 'desktop-kill)
 
 (defun desktop-kill ()
-  (if desktop-dirname
-      (condition-case err
-	  (desktop-save desktop-dirname)
-	(file-error
-	 (if (yes-or-no-p "Error while saving the desktop.  Quit anyway? ")
-	     nil
-	   (signal (car err) (cdr err)))))))
+  "If `desktop-save-mode' is non-nil, do what `desktop-save' says to do.
+If the desktop should be saved and `desktop-dirname'
+is nil, ask the user where to save the desktop."
+  (when (and desktop-save-mode
+             (let ((exists (file-exists-p (desktop-full-file-name))))
+               (or (eq desktop-save t)
+                   (and exists (memq desktop-save '(ask-if-new if-exists)))
+                   (and
+                    (or (memq desktop-save '(ask ask-if-new))
+                        (and exists (eq desktop-save 'ask-if-exists)))
+                    (y-or-n-p "Save desktop? ")))))
+    (unless desktop-dirname
+      (setq desktop-dirname
+            (file-name-as-directory
+             (expand-file-name
+	      (read-directory-name "Directory for desktop file: " nil nil t)))))
+    (condition-case err
+	(desktop-save desktop-dirname t)
+      (file-error
+       (unless (yes-or-no-p "Error while saving the desktop.  Ignore? ")
+	 (signal (car err) (cdr err))))))
+  ;; If we own it, we don't anymore.
+  (when (eq (emacs-pid) (desktop-owner)) (desktop-release-lock)))
+
 ;; ----------------------------------------------------------------------------
 (defun desktop-list* (&rest args)
   (if (null (cdr args))
@@ -228,343 +647,654 @@ the like shorter.")
 	(setq args (cdr args)))
       value)))
 
-(defun desktop-internal-v2s (val)
+;; ----------------------------------------------------------------------------
+(defun desktop-buffer-info (buffer)
+  (set-buffer buffer)
+  (list
+   ;; base name of the buffer; replaces the buffer name if managed by uniquify
+   (and (fboundp 'uniquify-buffer-base-name) (uniquify-buffer-base-name))
+   ;; basic information
+   (desktop-file-name (buffer-file-name) desktop-dirname)
+   (buffer-name)
+   major-mode
+   ;; minor modes
+   (let (ret)
+     (mapc
+      #'(lambda (minor-mode)
+	  (and (boundp minor-mode)
+	       (symbol-value minor-mode)
+	       (let* ((special (assq minor-mode desktop-minor-mode-table))
+		      (value (cond (special (cadr special))
+				   ((functionp minor-mode) minor-mode))))
+		 (when value (add-to-list 'ret value)))))
+      (mapcar #'car minor-mode-alist))
+     ret)
+   ;; point and mark, and read-only status
+   (point)
+   (list (mark t) mark-active)
+   buffer-read-only
+   ;; auxiliary information
+   (when (functionp desktop-save-buffer)
+     (funcall desktop-save-buffer desktop-dirname))
+   ;; local variables
+   (let ((locals desktop-locals-to-save)
+	 (loclist (buffer-local-variables))
+	 (ll))
+     (while locals
+       (let ((here (assq (car locals) loclist)))
+	 (if here
+	     (setq ll (cons here ll))
+	   (when (member (car locals) loclist)
+	     (setq ll (cons (car locals) ll)))))
+       (setq locals (cdr locals)))
+     ll)))
+
+;; ----------------------------------------------------------------------------
+(defun desktop-internal-v2s (value)
   "Convert VALUE to a pair (QUOTE . TXT); (eval (read TXT)) gives VALUE.
 TXT is a string that when read and evaluated yields value.
 QUOTE may be `may' (value may be quoted),
 `must' (values must be quoted), or nil (value may not be quoted)."
   (cond
-   ((or (numberp val) (null val) (eq t val))
-    (cons 'may (prin1-to-string val)))
-   ((stringp val)
-    (let ((copy (copy-sequence val)))
-      (set-text-properties 0 (length copy) nil copy)
-      ;; Get rid of text properties because we cannot read them
-      (cons 'may (prin1-to-string copy))))
-   ((symbolp val)
-    (cons 'must (prin1-to-string val)))
-   ((vectorp val)
-    (let* ((special nil)
-	   (pass1 (mapcar
-		   (lambda (el)
-		     (let ((res (desktop-internal-v2s el)))
-		       (if (null (car res))
-			   (setq special t))
-		       res))
-		   val)))
-      (if special
-	  (cons nil (concat "(vector "
-			    (mapconcat (lambda (el)
-					 (if (eq (car el) 'must)
-					     (concat "'" (cdr el))
-					   (cdr el)))
-				       pass1
-				       " ")
-			    ")"))
-	(cons 'may (concat "[" (mapconcat 'cdr pass1 " ") "]")))))
-   ((consp val)
-    (let ((p val)
-	  newlist
-	  use-list*
-	  anynil)
-      (while (consp p)
-	(let ((q.txt (desktop-internal-v2s (car p))))
-	  (or anynil (setq anynil (null (car q.txt))))
-	  (setq newlist (cons q.txt newlist)))
-	(setq p (cdr p)))
-      (if p
-	  (let ((last (desktop-internal-v2s p))
-		(el (car newlist)))
-	    (or anynil (setq anynil (null (car last))))
-	    (or anynil
-		(setq newlist (cons '(must . ".") newlist)))
-	    (setq use-list* t)
-	    (setq newlist (cons last newlist))))
-      (setq newlist (nreverse newlist))
-      (if anynil
-	  (cons nil
-		(concat (if use-list* "(desktop-list* "  "(list ")
-			(mapconcat (lambda (el)
-				     (if (eq (car el) 'must)
-					 (concat "'" (cdr el))
-				       (cdr el)))
-				   newlist
-				   " ")
-			")"))
-	(cons 'must
-	      (concat "(" (mapconcat 'cdr newlist " ") ")")))))
-   ((subrp val)
-    (cons nil (concat "(symbol-function '"
-		      (substring (prin1-to-string val) 7 -1)
-		      ")")))
-   ((markerp val)
-    (let ((pos (prin1-to-string (marker-position val)))
-	  (buf (prin1-to-string (buffer-name (marker-buffer val)))))
-      (cons nil (concat "(let ((mk (make-marker)))"
-			" (add-hook 'desktop-delay-hook"
-			" (list 'lambda '() (list 'set-marker mk "
-			pos " (get-buffer " buf ")))) mk)"))))
-   (t					; save as text
-    (cons 'may "\"Unprintable entity\""))))
-
-(defun desktop-value-to-string (val)
+    ((or (numberp value) (null value) (eq t value) (keywordp value))
+     (cons 'may (prin1-to-string value)))
+    ((stringp value)
+     (let ((copy (copy-sequence value)))
+       (set-text-properties 0 (length copy) nil copy)
+       ;; Get rid of text properties because we cannot read them
+       (cons 'may (prin1-to-string copy))))
+    ((symbolp value)
+     (cons 'must (prin1-to-string value)))
+    ((vectorp value)
+     (let* ((special nil)
+	    (pass1 (mapcar
+		    (lambda (el)
+		      (let ((res (desktop-internal-v2s el)))
+			(if (null (car res))
+			    (setq special t))
+			res))
+		    value)))
+       (if special
+	   (cons nil (concat "(vector "
+			     (mapconcat (lambda (el)
+					  (if (eq (car el) 'must)
+					      (concat "'" (cdr el))
+					    (cdr el)))
+					pass1
+					" ")
+			     ")"))
+	 (cons 'may (concat "[" (mapconcat 'cdr pass1 " ") "]")))))
+    ((consp value)
+     (let ((p value)
+	   newlist
+	   use-list*
+	   anynil)
+       (while (consp p)
+	 (let ((q.txt (desktop-internal-v2s (car p))))
+	   (or anynil (setq anynil (null (car q.txt))))
+	   (setq newlist (cons q.txt newlist)))
+	 (setq p (cdr p)))
+       (if p
+	   (let ((last (desktop-internal-v2s p)))
+	     (or anynil (setq anynil (null (car last))))
+	     (or anynil
+		 (setq newlist (cons '(must . ".") newlist)))
+	     (setq use-list* t)
+	     (setq newlist (cons last newlist))))
+       (setq newlist (nreverse newlist))
+       (if anynil
+	   (cons nil
+		 (concat (if use-list* "(desktop-list* "  "(list ")
+			 (mapconcat (lambda (el)
+				      (if (eq (car el) 'must)
+					  (concat "'" (cdr el))
+					(cdr el)))
+				    newlist
+				    " ")
+			 ")"))
+	 (cons 'must
+	       (concat "(" (mapconcat 'cdr newlist " ") ")")))))
+    ((subrp value)
+     (cons nil (concat "(symbol-function '"
+		       (substring (prin1-to-string value) 7 -1)
+		       ")")))
+    ((markerp value)
+     (let ((pos (prin1-to-string (marker-position value)))
+	   (buf (prin1-to-string (buffer-name (marker-buffer value)))))
+       (cons nil (concat "(let ((mk (make-marker)))"
+			 " (add-hook 'desktop-delay-hook"
+			 " (list 'lambda '() (list 'set-marker mk "
+			 pos " (get-buffer " buf ")))) mk)"))))
+    (t					 ; save as text
+     (cons 'may "\"Unprintable entity\""))))
+
+;; ----------------------------------------------------------------------------
+(defun desktop-value-to-string (value)
   "Convert VALUE to a string that when read evaluates to the same value.
 Not all types of values are supported."
   (let* ((print-escape-newlines t)
 	 (float-output-format nil)
-	 (quote.txt (desktop-internal-v2s val))
+	 (quote.txt (desktop-internal-v2s value))
 	 (quote (car quote.txt))
 	 (txt (cdr quote.txt)))
     (if (eq quote 'must)
 	(concat "'" txt)
       txt)))
+
 ;; ----------------------------------------------------------------------------
 (defun desktop-outvar (varspec)
   "Output a setq statement for variable VAR to the desktop file.
 The argument VARSPEC may be the variable name VAR (a symbol),
-or a cons cell of the form  (VAR . MAX-SIZE),
+or a cons cell of the form (VAR . MAX-SIZE),
 which means to truncate VAR's value to at most MAX-SIZE elements
 \(if the value is a list) before saving the value."
   (let (var size)
     (if (consp varspec)
 	(setq var (car varspec) size (cdr varspec))
       (setq var varspec))
-    (if (boundp var)
-	(progn
-	  (if (and (integerp size)
-		   (> size 0)
-		   (listp (eval var)))
-	      (desktop-truncate (eval var) size)) 
-	  (insert "(setq "
-		  (symbol-name var)
-		  " "
-		  (desktop-value-to-string (symbol-value var))
-		  ")\n")))))
+    (when (boundp var)
+      (when (and (integerp size)
+		 (> size 0)
+		 (listp (eval var)))
+	(desktop-truncate (eval var) size))
+      (insert "(setq "
+	      (symbol-name var)
+	      " "
+	      (desktop-value-to-string (symbol-value var))
+	      ")\n"))))
+
 ;; ----------------------------------------------------------------------------
 (defun desktop-save-buffer-p (filename bufname mode &rest dummy)
-  "Return t if the desktop should record a particular buffer for next startup.
+  "Return t if buffer should have its state saved in the desktop file.
 FILENAME is the visited file name, BUFNAME is the buffer name, and
-MODE is the major mode."
+MODE is the major mode.
+\n\(fn FILENAME BUFNAME MODE)"
   (let ((case-fold-search nil))
-    (or (and filename
-	     (not (string-match desktop-buffers-not-to-save bufname))
-	     (not (string-match desktop-files-not-to-save filename)))
-	(and (eq mode 'dired-mode)
-	     (save-excursion
-	       (set-buffer (get-buffer bufname))
-	       (not (string-match desktop-files-not-to-save
-				  default-directory))))
-	(and (null filename)
-	     (memq mode '(Info-mode rmail-mode))))))
+    (and (not (string-match desktop-buffers-not-to-save bufname))
+         (not (memq mode desktop-modes-not-to-save))
+         (or (and filename
+                  (not (string-match desktop-files-not-to-save filename)))
+             (and (eq mode 'dired-mode)
+                  (with-current-buffer bufname
+                    (not (string-match desktop-files-not-to-save
+                                       default-directory))))
+             (and (null filename)
+		  (with-current-buffer bufname desktop-save-buffer))))))
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-save (dirname)
-  "Save the Desktop file.  Parameter DIRNAME specifies where to save desktop."
+(defun desktop-file-name (filename dirname)
+  "Convert FILENAME to format specified in `desktop-file-name-format'.
+DIRNAME must be the directory in which the desktop file will be saved."
+  (cond
+    ((not filename) nil)
+    ((eq desktop-file-name-format 'tilde)
+     (let ((relative-name (file-relative-name (expand-file-name filename) "~")))
+       (cond
+         ((file-name-absolute-p relative-name) relative-name)
+         ((string= "./" relative-name) "~/")
+         ((string= "." relative-name) "~")
+         (t (concat "~/" relative-name)))))
+    ((eq desktop-file-name-format 'local) (file-relative-name filename dirname))
+    (t (expand-file-name filename))))
+
+;; ----------------------------------------------------------------------------
+;;;###autoload
+(defun desktop-save (dirname &optional release)
+  "Save the desktop in a desktop file.
+Parameter DIRNAME specifies where to save the desktop file.
+Optional parameter RELEASE says whether we're done with this desktop.
+See also `desktop-base-file-name'."
   (interactive "DDirectory to save desktop file in: ")
-  (run-hooks 'desktop-save-hook)
+  (setq desktop-dirname (file-name-as-directory (expand-file-name dirname)))
   (save-excursion
-    (let ((filename (expand-file-name
-		     (concat dirname desktop-basefilename)))
-	  (info (nreverse
-		 (mapcar
-		  (function (lambda (b)
-			      (set-buffer b)
-			      (list
-			       (buffer-file-name)
-			       (buffer-name)
-			       major-mode
-			       (list	; list explaining minor modes
-				(not (null auto-fill-function)))
-			       (point)
-			       (list (mark t) mark-active)
-			       buffer-read-only
-			       (cond ((eq major-mode 'Info-mode)
-				      (list Info-current-file
-					    Info-current-node))
-				     ((eq major-mode 'dired-mode)
-				      (cons
-				       (expand-file-name dired-directory)
-				       (cdr
-					(nreverse
-					 (mapcar
-					  (function car)
-					  dired-subdir-alist))))))
-			       (let ((locals desktop-locals-to-save)
-				     (loclist (buffer-local-variables))
-				     (ll))
-				 (while locals
-				   (let ((here (assq (car locals) loclist)))
-				     (if here
-					 (setq ll (cons here ll))
-				       (if (member (car locals) loclist)
-					   (setq ll (cons (car locals) ll)))))
-				   (setq locals (cdr locals)))
-				 ll)
-			       )))
-		  (buffer-list))))
-	  (buf (get-buffer-create "*desktop*")))
-      (set-buffer buf)
-      (erase-buffer)
-
-      (insert desktop-header
-	      ";; Created " (current-time-string) "\n"
-	      ";; Emacs version " emacs-version "\n\n"
-	      ";; Global section:\n")
-      (mapcar (function desktop-outvar) desktop-globals-to-save)
-      (if (memq 'kill-ring desktop-globals-to-save)
-	  (insert "(setq kill-ring-yank-pointer (nthcdr "
-		  (int-to-string
-		   (- (length kill-ring) (length kill-ring-yank-pointer)))
-		  " kill-ring))\n"))
-
-      (insert "\n;; Buffer section:\n")
-      (mapcar
-       (function (lambda (l)
-		   (if (apply 'desktop-save-buffer-p l)
-		       (progn
-			 (insert desktop-create-buffer-form)
-			 (mapcar
-			  (function (lambda (e)
-				      (insert "\n  "
-					      (desktop-value-to-string e))))
-			  l)
-			 (insert ")\n\n")))))
-       info)
-      (setq default-directory dirname)
-      (if (file-exists-p filename) (delete-file filename))
-      (write-region (point-min) (point-max) filename nil 'nomessage)))
-  (setq desktop-dirname dirname))
+    (let ((eager desktop-restore-eager)
+	  (new-modtime (nth 5 (file-attributes (desktop-full-file-name)))))
+      (when
+	  (or (not new-modtime)		; nothing to overwrite
+	      (equal desktop-file-modtime new-modtime)
+	      (yes-or-no-p (if desktop-file-modtime
+			       (if (> (float-time new-modtime) (float-time desktop-file-modtime))
+				   "Desktop file is more recent than the one loaded.  Save anyway? "
+				 "Desktop file isn't the one loaded.  Overwrite it? ")
+			     "Current desktop was not loaded from a file.  Overwrite this desktop file? "))
+	      (unless release (error "Desktop file conflict")))
+
+	;; If we're done with it, release the lock.
+	;; Otherwise, claim it if it's unclaimed or if we created it.
+	(if release
+	    (desktop-release-lock)
+	  (unless (and new-modtime (desktop-owner)) (desktop-claim-lock)))
+
+	(with-temp-buffer
+	  (insert
+	   ";; -*- mode: emacs-lisp; coding: emacs-mule; -*-\n"
+	   desktop-header
+	   ";; Created " (current-time-string) "\n"
+	   ";; Desktop file format version " desktop-file-version "\n"
+	   ";; Emacs version " emacs-version "\n")
+	  (save-excursion (run-hooks 'desktop-save-hook))
+	  (goto-char (point-max))
+	  (insert "\n;; Global section:\n")
+	  (mapc (function desktop-outvar) desktop-globals-to-save)
+	  (when (memq 'kill-ring desktop-globals-to-save)
+	    (insert
+	     "(setq kill-ring-yank-pointer (nthcdr "
+	     (int-to-string (- (length kill-ring) (length kill-ring-yank-pointer)))
+	     " kill-ring))\n"))
+
+	  (insert "\n;; Buffer section -- buffers listed in same order as in buffer list:\n")
+	  (dolist (l (mapcar 'desktop-buffer-info (buffer-list)))
+	    (let ((base (pop l)))
+	      (when (apply 'desktop-save-buffer-p l)
+		(insert "("
+			(if (or (not (integerp eager))
+				(if (zerop eager)
+				    nil
+				  (setq eager (1- eager))))
+			    "desktop-create-buffer"
+			  "desktop-append-buffer-args")
+			" "
+			desktop-file-version)
+		;; If there's a non-empty base name, we save it instead of the buffer name
+		(when (and base (not (string= base "")))
+		  (setcar (nthcdr 1 l) base))
+		(dolist (e l)
+		  (insert "\n  " (desktop-value-to-string e)))
+		(insert ")\n\n"))))
+
+	  (setq default-directory desktop-dirname)
+	  (let ((coding-system-for-write 'emacs-mule))
+	    (write-region (point-min) (point-max) (desktop-full-file-name) nil 'nomessage))
+	  ;; We remember when it was modified (which is presumably just now).
+	  (setq desktop-file-modtime (nth 5 (file-attributes (desktop-full-file-name)))))))))
+
 ;; ----------------------------------------------------------------------------
+;;;###autoload
 (defun desktop-remove ()
-  "Delete the Desktop file and inactivate the desktop system."
+  "Delete desktop file in `desktop-dirname'.
+This function also sets `desktop-dirname' to nil."
   (interactive)
-  (if desktop-dirname
-      (let ((filename (concat desktop-dirname desktop-basefilename)))
-	(setq desktop-dirname nil)
-	(if (file-exists-p filename)
-	    (delete-file filename)))))
+  (when desktop-dirname
+    (let ((filename (desktop-full-file-name)))
+      (setq desktop-dirname nil)
+      (when (file-exists-p filename)
+        (delete-file filename)))))
+
+(defvar desktop-buffer-args-list nil
+  "List of args for `desktop-create-buffer'.")
+
+(defvar desktop-lazy-timer nil)
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-read ()
-  "Read the Desktop file and the files it specifies.
-This is a no-op when Emacs is running in batch mode."
+;;;###autoload
+(defun desktop-read (&optional dirname)
+  "Read and process the desktop file in directory DIRNAME.
+Look for a desktop file in DIRNAME, or if DIRNAME is omitted, look in
+directories listed in `desktop-path'.  If a desktop file is found, it
+is processed and `desktop-after-read-hook' is run.  If no desktop file
+is found, clear the desktop and run `desktop-no-desktop-file-hook'.
+This function is a no-op when Emacs is running in batch mode.
+It returns t if a desktop file was loaded, nil otherwise."
   (interactive)
-  (if noninteractive
-      nil
-    (let ((dirs '("./" "~/")))
-      (while (and dirs
-		  (not (file-exists-p (expand-file-name
-				       desktop-basefilename
-				       (car dirs)))))
-	(setq dirs (cdr dirs)))
-      (setq desktop-dirname (and dirs (expand-file-name (car dirs))))
-      (if desktop-dirname
-	  (progn
-	    (load (expand-file-name desktop-basefilename desktop-dirname)
-		  t t t)
+  (unless noninteractive
+    (setq desktop-dirname
+          (file-name-as-directory
+           (expand-file-name
+            (or
+             ;; If DIRNAME is specified, use it.
+             (and (< 0 (length dirname)) dirname)
+             ;; Otherwise search desktop file in desktop-path.
+             (let ((dirs desktop-path))
+               (while (and dirs
+                           (not (file-exists-p
+                                 (desktop-full-file-name (car dirs)))))
+                 (setq dirs (cdr dirs)))
+               (and dirs (car dirs)))
+             ;; If not found and `desktop-path' is non-nil, use its first element.
+             (and desktop-path (car desktop-path))
+             ;; Default: Home directory.
+             "~"))))
+    (if (file-exists-p (desktop-full-file-name))
+	;; Desktop file found, but is it already in use?
+	(let ((desktop-first-buffer nil)
+	      (desktop-buffer-ok-count 0)
+	      (desktop-buffer-fail-count 0)
+	      (owner (desktop-owner))
+	      ;; Avoid desktop saving during evaluation of desktop buffer.
+	      (desktop-save nil))
+	  (if (and owner
+		   (memq desktop-load-locked-desktop '(nil ask))
+		   (or (null desktop-load-locked-desktop)
+		       (not (y-or-n-p (format "Warning: desktop file appears to be in use by PID %s.\n\
+Using it may cause conflicts.  Use it anyway? " owner)))))
+	      (let ((default-directory desktop-dirname))
+		(setq desktop-dirname nil)
+		(run-hooks 'desktop-not-loaded-hook)
+		(unless desktop-dirname
+		  (message "Desktop file in use; not loaded.")))
+	    (desktop-lazy-abort)
+	    ;; Evaluate desktop buffer and remember when it was modified.
+	    (load (desktop-full-file-name) t t t)
+	    (setq desktop-file-modtime (nth 5 (file-attributes (desktop-full-file-name))))
+	    ;; If it wasn't already, mark it as in-use, to bother other
+	    ;; desktop instances.
+	    (unless owner
+	      (condition-case nil
+		  (desktop-claim-lock)
+		(file-error (message "Couldn't record use of desktop file")
+			    (sit-for 1))))
+
+	    ;; `desktop-create-buffer' puts buffers at end of the buffer list.
+	    ;; We want buffers existing prior to evaluating the desktop (and
+	    ;; not reused) to be placed at the end of the buffer list, so we
+	    ;; move them here.
+	    (mapc 'bury-buffer
+		  (nreverse (cdr (memq desktop-first-buffer (nreverse (buffer-list))))))
+	    (switch-to-buffer (car (buffer-list)))
 	    (run-hooks 'desktop-delay-hook)
 	    (setq desktop-delay-hook nil)
-	    (message "Desktop loaded."))
-	(desktop-clear)))))
+	    (run-hooks 'desktop-after-read-hook)
+	    (message "Desktop: %d buffer%s restored%s%s."
+		     desktop-buffer-ok-count
+		     (if (= 1 desktop-buffer-ok-count) "" "s")
+		     (if (< 0 desktop-buffer-fail-count)
+			 (format ", %d failed to restore" desktop-buffer-fail-count)
+		       "")
+		     (if desktop-buffer-args-list
+			 (format ", %d to restore lazily"
+				 (length desktop-buffer-args-list))
+		       ""))
+	    t))
+      ;; No desktop file found.
+      (desktop-clear)
+      (let ((default-directory desktop-dirname))
+        (run-hooks 'desktop-no-desktop-file-hook))
+      (message "No desktop file.")
+      nil)))
+
 ;; ----------------------------------------------------------------------------
+;; Maintained for backward compatibility
+;;;###autoload
 (defun desktop-load-default ()
   "Load the `default' start-up library manually.
-Also inhibit further loading of it.  Call this from your `.emacs' file
-to provide correct modes for autoloaded files."
-  (if (not inhibit-default-init)	; safety check
-      (progn
-	(load "default" t t)
-	(setq inhibit-default-init t))))
-;; ----------------------------------------------------------------------------
-;; Note: the following functions use the dynamic variable binding in Lisp.
-;;
-(defun desktop-buffer-info () "Load an info file."
-  (if (eq 'Info-mode mam)
-      (progn
-	(require 'info)
-	(Info-find-node (nth 0 misc) (nth 1 misc))
-	t)))
+Also inhibit further loading of it."
+  (unless inhibit-default-init	        ; safety check
+    (load "default" t t)
+    (setq inhibit-default-init t)))
+(make-obsolete 'desktop-load-default
+               'desktop-save-mode "22.1")
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-buffer-rmail () "Load an RMAIL file."
-  (if (eq 'rmail-mode mam)
-      (condition-case error
-	  (progn (rmail-input fn) t)
-	(file-locked
-	 (kill-buffer (current-buffer))
-	 'ignored))))
+;;;###autoload
+(defun desktop-change-dir (dirname)
+  "Change to desktop saved in DIRNAME.
+Kill the desktop as specified by variables `desktop-save-mode' and
+`desktop-save', then clear the desktop and load the desktop file in
+directory DIRNAME."
+  (interactive "DChange to directory: ")
+  (setq dirname (file-name-as-directory (expand-file-name dirname desktop-dirname)))
+  (desktop-kill)
+  (desktop-clear)
+  (desktop-read dirname))
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-buffer-mh () "Load a folder in the mh system."
-  (if (eq 'mh-folder-mode mam)
-      (progn
-	(require 'mh-e)
-	(mh-find-path)
-	(mh-visit-folder bn)
-	t)))
+;;;###autoload
+(defun desktop-save-in-desktop-dir ()
+  "Save the desktop in directory `desktop-dirname'."
+  (interactive)
+  (if desktop-dirname
+      (desktop-save desktop-dirname)
+    (call-interactively 'desktop-save))
+  (message "Desktop saved in %s" desktop-dirname))
+
 ;; ----------------------------------------------------------------------------
-(defun desktop-buffer-dired () "Load a directory using dired."
-  (if (eq 'dired-mode mam)
-      (if (file-directory-p (file-name-directory (car misc)))
-	  (progn
-	    (dired (car misc))
-	    (mapcar 'dired-insert-subdir (cdr misc))
-	    t)
-	(message "Directory %s no longer exists." (car misc))
-	(sit-for 1)
-	'ignored)))
+;;;###autoload
+(defun desktop-revert ()
+  "Revert to the last loaded desktop."
+  (interactive)
+  (unless desktop-dirname
+    (error "Unknown desktop directory"))
+  (unless (file-exists-p (desktop-full-file-name))
+    (error "No desktop file found"))
+  (desktop-clear)
+  (desktop-read desktop-dirname))
+
+(defvar desktop-buffer-major-mode)
+(defvar desktop-buffer-locals)
 ;; ----------------------------------------------------------------------------
-(defun desktop-buffer-file () "Load a file."
-  (if fn
-      (if (or (file-exists-p fn)
-	      (and desktop-missing-file-warning
-		   (y-or-n-p (format
-			      "File \"%s\" no longer exists. Re-create? "
-			      fn))))
-	  (progn (find-file fn) t)
-	'ignored)))
+(defun desktop-restore-file-buffer (desktop-buffer-file-name
+                                    desktop-buffer-name
+                                    desktop-buffer-misc)
+  "Restore a file buffer."
+  (when desktop-buffer-file-name
+    (if (or (file-exists-p desktop-buffer-file-name)
+	    (let ((msg (format "Desktop: File \"%s\" no longer exists."
+			       desktop-buffer-file-name)))
+	      (if desktop-missing-file-warning
+		  (y-or-n-p (concat msg " Re-create buffer? "))
+		(message "%s" msg)
+		nil)))
+	(let* ((auto-insert nil) ; Disable auto insertion
+	       (coding-system-for-read
+		(or coding-system-for-read
+		    (cdr (assq 'buffer-file-coding-system
+			       desktop-buffer-locals))))
+	       (buf (find-file-noselect desktop-buffer-file-name)))
+	  (condition-case nil
+	      (switch-to-buffer buf)
+	    (error (pop-to-buffer buf)))
+	  (and (not (eq major-mode desktop-buffer-major-mode))
+	       (functionp desktop-buffer-major-mode)
+	       (funcall desktop-buffer-major-mode))
+	  buf)
+      nil)))
+
+(defun desktop-load-file (function)
+  "Load the file where auto loaded FUNCTION is defined."
+  (when function
+    (let ((fcell (and (fboundp function) (symbol-function function))))
+      (when (and (listp fcell)
+                 (eq 'autoload (car fcell)))
+        (load (cadr fcell))))))
+
 ;; ----------------------------------------------------------------------------
-;; Create a buffer, load its file, set is mode, ...;  called from Desktop file
-;; only.
-(defun desktop-create-buffer (ver fn bn mam mim pt mk ro misc &optional locals)
-  (let ((hlist desktop-buffer-handlers)
-	(result)
-	(handler))
-    (while (and (not result) hlist)
-      (setq handler (car hlist))
-      (setq result (funcall handler))
-      (setq hlist (cdr hlist)))
-    (if (eq result t)
-	(progn
-	  (if (not (equal (buffer-name) bn))
-	      (rename-buffer bn))
-	  (auto-fill-mode (if (nth 0 mim) 1 0))
-	  (goto-char pt)
-	  (if (consp mk)
+;; Create a buffer, load its file, set its mode, ...;
+;; called from Desktop file only.
+
+;; Just to silence the byte compiler.
+
+(defvar desktop-first-buffer)          ; Dynamically bound in `desktop-read'
+
+;; Bound locally in `desktop-read'.
+(defvar desktop-buffer-ok-count)
+(defvar desktop-buffer-fail-count)
+
+(defun desktop-create-buffer
+  (desktop-file-version
+   desktop-buffer-file-name
+   desktop-buffer-name
+   desktop-buffer-major-mode
+   desktop-buffer-minor-modes
+   desktop-buffer-point
+   desktop-buffer-mark
+   desktop-buffer-read-only
+   desktop-buffer-misc
+   &optional
+   desktop-buffer-locals)
+  ;; To make desktop files with relative file names possible, we cannot
+  ;; allow `default-directory' to change. Therefore we save current buffer.
+  (save-current-buffer
+    ;; Give major mode module a chance to add a handler.
+    (desktop-load-file desktop-buffer-major-mode)
+    (let ((buffer-list (buffer-list))
+          (result
+           (condition-case err
+               (funcall (or (cdr (assq desktop-buffer-major-mode
+                                       desktop-buffer-mode-handlers))
+                            'desktop-restore-file-buffer)
+                        desktop-buffer-file-name
+                        desktop-buffer-name
+                        desktop-buffer-misc)
+             (error
+              (message "Desktop: Can't load buffer %s: %s"
+                       desktop-buffer-name
+                       (error-message-string err))
+              (when desktop-missing-file-warning (sit-for 1))
+              nil))))
+      (if (bufferp result)
+          (setq desktop-buffer-ok-count (1+ desktop-buffer-ok-count))
+        (setq desktop-buffer-fail-count (1+ desktop-buffer-fail-count))
+        (setq result nil))
+      ;; Restore buffer list order with new buffer at end. Don't change
+      ;; the order for old desktop files (old desktop module behaviour).
+      (unless (< desktop-file-version 206)
+        (mapc 'bury-buffer buffer-list)
+        (when result (bury-buffer result)))
+      (when result
+        (unless (or desktop-first-buffer (< desktop-file-version 206))
+          (setq desktop-first-buffer result))
+        (set-buffer result)
+        (unless (equal (buffer-name) desktop-buffer-name)
+          (rename-buffer desktop-buffer-name t))
+        ;; minor modes
+        (cond ((equal '(t) desktop-buffer-minor-modes) ; backwards compatible
+               (auto-fill-mode 1))
+              ((equal '(nil) desktop-buffer-minor-modes) ; backwards compatible
+               (auto-fill-mode 0))
+              (t
+               (dolist (minor-mode desktop-buffer-minor-modes)
+                 ;; Give minor mode module a chance to add a handler.
+                 (desktop-load-file minor-mode)
+                 (let ((handler (cdr (assq minor-mode desktop-minor-mode-handlers))))
+                   (if handler
+                       (funcall handler desktop-buffer-locals)
+                     (when (functionp minor-mode)
+                       (funcall minor-mode 1)))))))
+        ;; Even though point and mark are non-nil when written by
+        ;; `desktop-save', they may be modified by handlers wanting to set
+        ;; point or mark themselves.
+        (when desktop-buffer-point
+          (goto-char
+            (condition-case err
+                ;; Evaluate point.  Thus point can be something like
+                ;; '(search-forward ...
+                (eval desktop-buffer-point)
+              (error (message "%s" (error-message-string err)) 1))))
+        (when desktop-buffer-mark
+          (if (consp desktop-buffer-mark)
 	      (progn
-		(set-mark (car mk))
-		(setq mark-active (car (cdr mk))))
-	    (set-mark mk))
-	  ;; Never override file system if the file really is read-only marked.
-	  (if ro (setq buffer-read-only ro))
-	  (while locals
-	    (let ((this (car locals)))
-	      (if (consp this)
-		  ;; an entry of this form `(symbol . value)'
-		  (progn
-		    (make-local-variable (car this))
-		    (set (car this) (cdr this)))
-		;; an entry of the form `symbol'
-		(make-local-variable this)
-		(makunbound this)))
-	    (setq locals (cdr locals)))
-	  ))))
+		(set-mark (car desktop-buffer-mark))
+		(setq mark-active (car (cdr desktop-buffer-mark))))
+            (set-mark desktop-buffer-mark)))
+        ;; Never override file system if the file really is read-only marked.
+        (when desktop-buffer-read-only (setq buffer-read-only desktop-buffer-read-only))
+        (while desktop-buffer-locals
+          (let ((this (car desktop-buffer-locals)))
+            (if (consp this)
+		;; an entry of this form `(symbol . value)'
+		(progn
+		  (make-local-variable (car this))
+		  (set (car this) (cdr this)))
+              ;; an entry of the form `symbol'
+              (make-local-variable this)
+              (makunbound this)))
+          (setq desktop-buffer-locals (cdr desktop-buffer-locals)))))))
 
+;; ----------------------------------------------------------------------------
 ;; Backward compatibility -- update parameters to 205 standards.
-(defun desktop-buffer (fn bn mam mim pt mk ro tl fc cfs cr misc)
-  (desktop-create-buffer 205 fn bn mam (cdr mim) pt mk ro misc
+(defun desktop-buffer (desktop-buffer-file-name desktop-buffer-name
+		       desktop-buffer-major-mode
+		       mim pt mk ro tl fc cfs cr desktop-buffer-misc)
+  (desktop-create-buffer 205 desktop-buffer-file-name desktop-buffer-name
+			 desktop-buffer-major-mode (cdr mim) pt mk ro
+			 desktop-buffer-misc
 			 (list (cons 'truncate-lines tl)
 			       (cons 'fill-column fc)
 			       (cons 'case-fold-search cfs)
 			       (cons 'case-replace cr)
 			       (cons 'overwrite-mode (car mim)))))
+
+(defun desktop-append-buffer-args (&rest args)
+  "Append ARGS at end of `desktop-buffer-args-list'.
+ARGS must be an argument list for `desktop-create-buffer'."
+  (setq desktop-buffer-args-list (nconc desktop-buffer-args-list (list args)))
+  (unless desktop-lazy-timer
+    (setq desktop-lazy-timer
+          (run-with-idle-timer desktop-lazy-idle-delay t 'desktop-idle-create-buffers))))
+
+(defun desktop-lazy-create-buffer ()
+  "Pop args from `desktop-buffer-args-list', create buffer and bury it."
+  (when desktop-buffer-args-list
+    (let* ((remaining (length desktop-buffer-args-list))
+           (args (pop desktop-buffer-args-list))
+           (buffer-name (nth 2 args))
+           (msg (format "Desktop lazily opening %s (%s remaining)..."
+                            buffer-name remaining)))
+      (when desktop-lazy-verbose
+        (message "%s" msg))
+      (let ((desktop-first-buffer nil)
+            (desktop-buffer-ok-count 0)
+            (desktop-buffer-fail-count 0))
+        (apply 'desktop-create-buffer args)
+        (run-hooks 'desktop-delay-hook)
+        (setq desktop-delay-hook nil)
+        (bury-buffer (get-buffer buffer-name))
+        (when desktop-lazy-verbose
+          (message "%s%s" msg (if (> desktop-buffer-ok-count 0) "done" "failed")))))))
+
+(defun desktop-idle-create-buffers ()
+  "Create buffers until the user does something, then stop.
+If there are no buffers left to create, kill the timer."
+  (let ((repeat 1))
+    (while (and repeat desktop-buffer-args-list)
+      (save-window-excursion
+        (desktop-lazy-create-buffer))
+      (setq repeat (sit-for 0.2))
+    (unless desktop-buffer-args-list
+      (cancel-timer desktop-lazy-timer)
+      (setq desktop-lazy-timer nil)
+      (message "Lazy desktop load complete")
+      (sit-for 3)
+      (message "")))))
+
+(defun desktop-lazy-complete ()
+  "Run the desktop load to completion."
+  (interactive)
+  (let ((desktop-lazy-verbose t))
+    (while desktop-buffer-args-list
+      (save-window-excursion
+        (desktop-lazy-create-buffer)))
+    (message "Lazy desktop load complete")))
+
+(defun desktop-lazy-abort ()
+  "Abort lazy loading of the desktop."
+  (interactive)
+  (when desktop-lazy-timer
+    (cancel-timer desktop-lazy-timer)
+    (setq desktop-lazy-timer nil))
+  (when desktop-buffer-args-list
+    (setq desktop-buffer-args-list nil)
+    (when (interactive-p)
+      (message "Lazy desktop load aborted"))))
+
 ;; ----------------------------------------------------------------------------
+;; When `desktop-save-mode' is non-nil and "--no-desktop" is not specified on the
+;; command line, we do the rest of what it takes to use desktop, but do it
+;; after finishing loading the init file.
+;; We cannot use `command-switch-alist' to process "--no-desktop" because these
+;; functions are processed after `after-init-hook'.
+(add-hook
+  'after-init-hook
+  (lambda ()
+    (let ((key "--no-desktop"))
+      (when (member key command-line-args)
+        (setq command-line-args (delete key command-line-args))
+        (setq desktop-save-mode nil)))
+    (when desktop-save-mode
+      (desktop-read)
+      (setq inhibit-startup-screen t))))
+
 (provide 'desktop)
 
-;; desktop.el ends here.
+;; arch-tag: 221907c3-1771-4fd3-9c2e-c6f700c6ede9
+;;; desktop.el ends here