Add a new tar-copy-preserve-time variable

* lisp/tar-mode.el (tar-copy-preserve-time): New variable (bug#11882).
(tar-copy): Use it.

2 files changed, 20 insertions, 2 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 8f95496705f..63ab33bdd4a 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -554,6 +554,11 @@ current and the previous or the next line, as before.
 * Changes in Specialized Modes and Packages in Emacs 27.1
 
 ---
+** The 'C' command in 'tar-mode' will now preserve the timestamp of
+the extracted file if the new variable 'tar-copy-preserve-time' is
+non-nil.
+
+---
 ** 'autoconf-mode' is now used instead of 'm4-mode' for the
 acinclude.m4/aclocal.m4/acsite.m4 files.
 
diff --git a/lisp/tar-mode.el b/lisp/tar-mode.el
index 8e7e1945cbc..569b01f978b 100644
--- a/lisp/tar-mode.el
+++ b/lisp/tar-mode.el
@@ -127,6 +127,11 @@ the file never exists on disk."
 This information is useful, but it takes screen space away from file names."
   :type 'boolean)
 
+(defcustom tar-copy-preserve-time nil
+  "Non-nil means that Tar mode preserves the timestamp when copying files."
+  :type 'boolean
+  :version "27.1")
+
 (defvar tar-parse-info nil)
 (defvar tar-superior-buffer nil
   "Buffer containing the tar archive from which a member was extracted.")
@@ -1001,11 +1006,16 @@ actually appear on disk when you save the tar-file's buffer."
 (defun tar-copy (&optional to-file)
   "In Tar mode, extract this entry of the tar file into a file on disk.
 If TO-FILE is not supplied, it is prompted for, defaulting to the name of
-the current tar-entry."
+the current tar-entry.
+
+If `tar-copy-preserve-time' is non-nil, the original
+timestamp (if present in the tar file) will be used on the
+extracted file."
   (interactive (list (tar-read-file-name)))
   (let* ((descriptor (tar-get-descriptor))
          (name (tar-header-name descriptor))
          (size (tar-header-size descriptor))
+         (date (tar-header-date descriptor))
          (start (tar-header-data-start descriptor))
          (end (+ start size))
          (inhibit-file-name-handlers inhibit-file-name-handlers)
@@ -1024,7 +1034,10 @@ the current tar-entry."
                            inhibit-file-name-handlers))
                 inhibit-file-name-operation 'write-region))
       (let ((coding-system-for-write 'no-conversion))
-        (write-region start end to-file nil nil nil t)))
+        (write-region start end to-file nil nil nil t))
+      (when (and tar-copy-preserve-time
+                 date)
+        (set-file-times to-file date)))
     (message "Copied tar entry %s to %s" name to-file)))
 
 (defun tar-new-entry (filename &optional index)