- ;; First try simple backup, then the highest numbered of the
- ;; numbered backups.
- ;; Ignore the value of version-control because we look for existing
- ;; backups, which maybe were made earlier or by another user with
- ;; a different value of version-control.
- (setq fn (expand-file-name fn))
- (or
- (let ((bak (make-backup-file-name fn)))
- (if (file-exists-p bak) bak))
- (let* ((dir (file-name-directory fn))
- (base-versions (concat (file-name-nondirectory fn) ".~"))
- (bv-length (length base-versions)))
- (concat dir
- (car (sort
- (file-name-all-completions base-versions dir)
- ;; bv-length is a fluid var for backup-extract-version:
- (function
- (lambda (fn1 fn2)
- (> (backup-extract-version fn1)
- (backup-extract-version fn2))))))))))
+ (let ((handler (find-file-name-handler fn 'diff-latest-backup-file)))
+ (if handler
+ (funcall handler 'diff-latest-backup-file fn)
+ ;; First try simple backup, then the highest numbered of the
+ ;; numbered backups.
+ ;; Ignore the value of version-control because we look for existing
+ ;; backups, which maybe were made earlier or by another user with
+ ;; a different value of version-control.
+ (setq fn (file-chase-links (expand-file-name fn)))
+ (or
+ (let ((bak (make-backup-file-name fn)))
+ (if (file-exists-p bak) bak))
+ ;; We use BACKUPNAME to cope with backups stored in a different dir.
+ (let* ((backupname (car (find-backup-file-name fn)))
+ (dir (file-name-directory backupname))
+ (base-versions (concat (file-name-sans-versions
+ (file-name-nondirectory backupname))
+ ".~"))
+ (bv-length (length base-versions)))
+ (concat dir
+ (car (sort
+ (file-name-all-completions base-versions dir)
+ ;; bv-length is a fluid var for backup-extract-version:
+ (function
+ (lambda (fn1 fn2)
+ (> (backup-extract-version fn1)
+ (backup-extract-version fn2))))))))))))