diff options
| -rw-r--r-- | lisp/diff.el | 83 |
1 files changed, 36 insertions, 47 deletions
diff --git a/lisp/diff.el b/lisp/diff.el index 6a15bbb7102..885287f0ead 100644 --- a/lisp/diff.el +++ b/lisp/diff.el @@ -95,54 +95,43 @@ and a backup file for NEW is the default for OLD." old (expand-file-name old)) (diff-internal-diff "diff" (append diff-switches (list new old)) nil)) -(defun diff-sccs (new) - "Find and display the differences between OLD and SCCS files." - (interactive - (let (newf) - (list - (setq newf (buffer-file-name) - newf (if (and newf (file-exists-p newf)) - (read-file-name - (concat "Diff new file: (" - (file-name-nondirectory newf) ") ") - nil newf t) - (read-file-name "Diff new file: " nil nil t)))))) - - (message "Comparing SCCS file %s..." new) - (setq new (expand-file-name new)) - (if (file-exists-p (concat - (file-name-directory new) - "SCCS/s." - (file-name-nondirectory new))) - (diff-internal-diff "sccs" - (append '("diffs") diff-switches (list new)) - 2) - (error "%s does not exist" - (concat (file-name-directory new) "SCCS/s." - (file-name-nondirectory new))))) - -(defun diff-rcs (new) - "Find and display the differences between OLD and RCS files." - (interactive - (let (newf) - (list - (setq newf (buffer-file-name) - newf (if (and newf (file-exists-p newf)) - (read-file-name - (concat "Diff new file: (" - (file-name-nondirectory newf) ") ") - nil newf t) - (read-file-name "Diff new file: " nil nil t)))))) +(defun diff-backup (file) + "Diff this file with its backup file or vice versa. +Uses the latest backup, if there are several numerical backups. +If this file is a backup, diff it with its original. +The backup file is the first file given to `diff'." + (interactive "fDiff (file with backup): ") + (let (bak ori) + (if (backup-file-name-p file) + (setq bak file + ori (file-name-sans-versions file)) + (setq bak (or (diff-latest-backup-file file) + (error "No backup found for %s" file)) + ori file)) + (diff bak ori))) - (message "Comparing RCS file %s..." new) - (let* ((fullname (expand-file-name new)) - (rcsfile (concat (file-name-directory fullname) - "RCS/" - (file-name-nondirectory fullname) - diff-rcs-extension))) - (if (file-exists-p rcsfile) - (diff-internal-diff "rcsdiff" (append diff-switches (list fullname)) 4) - (error "%s does not exist" rcsfile)))) +(defun diff-latest-backup-file (fn) ; actually belongs into files.el + "Return the latest existing backup of FILE, or nil." + ;; 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)))))))))) (defun diff-internal-diff (diff-command sw strip) (let ((buffer-read-only nil)) |