branch: elpa/undo-fu-session
commit 2a543d41685908e8ab52a9bab7d1c9dafbb0b0ab
Author: Campbell Barton <ideasma...@gmail.com>
Commit: Campbell Barton <ideasma...@gmail.com>
Disable file locking when writing undo-data
This intended to fix #10, since it's possible the lock-file name
is too long to write. In general locking undo data doesn't achieve
the outcome intended for file locking (see code-comments) so disable it.
---
undo-fu-session.el | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/undo-fu-session.el b/undo-fu-session.el
index fbe097ad4d..7a33428efc 100755
--- a/undo-fu-session.el
+++ b/undo-fu-session.el
@@ -453,7 +453,21 @@ Argument PENDING-LIST an `pending-undo-list' compatible
list."
(progn
(with-temp-buffer
(insert-file-contents file-src-full)
- (write-region nil nil file-dst-full nil 0))
+ ;; Don't create lock-files for the following reasons:
+ ;; - The file name may be too long and fail to lock (see
#10).
+ ;; - Locking is already handled by saving the file from
which this undo-data
+ ;; is created so locking the undo-data if of limited use.
+ ;; - Small but unnecessary overhead.
+ ;;
+ ;; Having said this, there is a theoretical possibility two
emacs instances
+ ;; could write undo-data at once. Nevertheless, the
undo-data *must* be in
+ ;; sync with the file that is written (matching hash &
length),
+ ;; so there is practically no benefit in writing a file that
is "correct" with
+ ;; respect to locking, when the undo-data doesn't match the
file contents.
+ ;; In summary, we would either have to lock both files at
once, or locking
+ ;; when writing undo data close to useless.
+ (let ((create-lockfiles nil))
+ (write-region nil nil file-dst-full nil 0)))
(setq size-src (+ size-src (file-attribute-size
(file-attributes file-src-full))))
(setq size-dst (+ size-dst (file-attribute-size
(file-attributes file-dst-full))))
@@ -652,7 +666,8 @@ Argument PENDING-LIST an `pending-undo-list' compatible
list."
(prin1 content-header (current-buffer))
(write-char ?\n (current-buffer))
(prin1 content-data (current-buffer))
- (write-region nil nil undo-file nil 0)
+ (let ((create-lockfiles nil))
+ (write-region nil nil undo-file nil 0))
t)))))
(defun undo-fu-session--save-safe ()
