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Re: desktop.el: autosave?
From: |
Juri Linkov |
Subject: |
Re: desktop.el: autosave? |
Date: |
Thu, 11 Apr 2013 11:29:08 +0300 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (x86_64-pc-linux-gnu) |
> I don't think anyone had a problem with run-with-timer (I just skimmed back
> through the thread to check), so go ahead and change my patch to use it.
In the patch below a new option is `desktop-auto-save-timeout' instead
of `desktop-auto-save-interval' because it should be more like
`auto-save-timeout' instead of `auto-save-interval'.
`auto-save-timeout' is the number of seconds between auto-saves, but
`auto-save-interval' is the number of characters typed between auto-saves.
In terms of the desktop, an interval would rather mean a number of changes
in the buffer list or something like that. I'm not sure whether this is
useful, so the following patch implements only timer-based auto-saving:
=== modified file 'lisp/desktop.el'
--- lisp/desktop.el 2013-01-02 16:13:04 +0000
+++ lisp/desktop.el 2013-04-11 08:28:14 +0000
@@ -189,6 +189,17 @@ (defcustom desktop-save 'ask-if-new
:group 'desktop
:version "22.1")
+(defcustom desktop-auto-save-timeout nil
+ "Number of seconds between auto-saves of the desktop.
+Zero or nil means disable timer-based auto-saving."
+ :type '(choice (const :tag "Off" nil)
+ (integer :tag "Seconds"))
+ :set (lambda (symbol value)
+ (set-default symbol value)
+ (desktop-auto-save-update))
+ :group 'desktop
+ :version "24.4")
+
(defcustom desktop-load-locked-desktop 'ask
"Specifies whether the desktop should be loaded if locked.
Possible values are:
@@ -539,6 +550,10 @@ (defconst desktop-header
(defvar desktop-delay-hook nil
"Hooks run after all buffers are loaded; intended for internal use.")
+(defvar desktop-file-checksum nil
+ "Checksum of the last auto-saved contents of the desktop file.
+Used to avoid writing contents unchanged between auto-saves.")
+
;; ----------------------------------------------------------------------------
;; Desktop file conflict detection
(defvar desktop-file-modtime nil
@@ -854,11 +869,12 @@ (defun desktop-file-name (filename dirna
;; ----------------------------------------------------------------------------
;;;###autoload
-(defun desktop-save (dirname &optional release)
+(defun desktop-save (dirname &optional release auto-save)
"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'."
+If AUTO-SAVE is non-nil, compare the saved contents to the one last saved,
+and don't save the buffer if they are the same."
(interactive "DDirectory to save desktop file in: ")
(setq desktop-dirname (file-name-as-directory (expand-file-name dirname)))
(save-excursion
@@ -918,10 +934,17 @@ (defun desktop-save (dirname &optional r
(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)))))))))
+ ;; If auto-saving, avoid writing if nothing has changed since the
last write.
+ ;; Don't check 300 characters of the header that contains the
timestamp.
+ (let ((checksum (and auto-save (md5 (current-buffer)
+ (+ 300 (point-min)) (point-max)
+ 'emacs-mule))))
+ (unless (and auto-save (equal checksum desktop-file-checksum))
+ (let ((coding-system-for-write 'emacs-mule))
+ (write-region (point-min) (point-max) (desktop-full-file-name)
nil 'nomessage))
+ (setq desktop-file-checksum checksum)
+ ;; We remember when it was modified (which is presumably just
now).
+ (setq desktop-file-modtime (nth 5 (file-attributes
(desktop-full-file-name)))))))))))
;; ----------------------------------------------------------------------------
;;;###autoload
@@ -1075,6 +1098,37 @@ (defun desktop-save-in-desktop-dir ()
(message "Desktop saved in %s" (abbreviate-file-name desktop-dirname)))
;; ----------------------------------------------------------------------------
+;; Auto-Saving.
+(defvar desktop-auto-save-timer nil)
+
+(defun desktop-auto-save ()
+ "Save the desktop periodically.
+Called by the timer created in `desktop-auto-save-update'."
+ (when (and desktop-save-mode
+ (integerp desktop-auto-save-timeout)
+ (> desktop-auto-save-timeout 0)
+ ;; Avoid desktop saving during lazy loading.
+ (not desktop-lazy-timer)
+ ;; Save only to own desktop file.
+ (eq (emacs-pid) (desktop-owner))
+ desktop-dirname)
+ (desktop-save desktop-dirname nil t))
+ (desktop-auto-save-update))
+
+(defun desktop-auto-save-update ()
+ "Update the timer for next auto-saving.
+Cancel the previous timer and run a new timer when the number
+of seconds between auto-saves is a positive integer."
+ (when desktop-auto-save-timer
+ (cancel-timer desktop-auto-save-timer)
+ (setq desktop-auto-save-timer nil))
+ (when (and (integerp desktop-auto-save-timeout)
+ (> desktop-auto-save-timeout 0))
+ (setq desktop-auto-save-timer
+ (run-with-timer desktop-auto-save-timeout nil
+ 'desktop-auto-save))))
+
+;; ----------------------------------------------------------------------------
;;;###autoload
(defun desktop-revert ()
"Revert to the last loaded desktop."
@@ -1327,6 +1381,7 @@ (add-hook 'after-init-hook
(setq desktop-save-mode nil)))
(when desktop-save-mode
(desktop-read)
+ (desktop-auto-save-update)
(setq inhibit-startup-screen t))))
(provide 'desktop)