(tar-mode): Position point on the name of the first file.

(tar-extract): Detect coding-system of the archive member and
decode it like insert-file-contents does.
(tar-alter-one-field): Reposition point on the file name of the
current tar entry.
(tar-subfile-save-buffer): Encode the file when updating it in the
archive, and use the size of encoded text to update the header
block.  Set last-coding-system-used to coding-system of the file.
Restore point of tar-superior-buffer after updating the descriptor line.

diff --git a/lisp/tar-mode.el b/lisp/tar-mode.el
index 2571c92cf98b2c8ef7ac45a8f57e244229c63ef8..c7ebfc9406895598ca64944c3c855328b3aa7fb6 100644 (file)
--- a/lisp/tar-mode.el
+++ b/lisp/tar-mode.el
@@ -610,7 +610,8 @@ See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
   (widen)
   (if (and (boundp 'tar-header-offset) tar-header-offset)
       (narrow-to-region 1 tar-header-offset)
-      (tar-summarize-buffer))
+      (tar-summarize-buffer)
+      (tar-next-line 0))
   (run-hooks 'tar-mode-hook)
   )
 
@@ -743,6 +744,43 @@ appear on disk when you save the tar-file's buffer."
                      (expand-file-name (concat tarname "!" name)))
                (setq buffer-file-truename
                      (abbreviate-file-name buffer-file-name))
+               ;; We need to mimic the parts of insert-file-contents
+               ;; which determine the coding-system and decode the text.
+               (let ((coding
+                      (and set-auto-coding-function
+                           (funcall
+                            set-auto-coding-function
+                            (if (< (point-max) 4096)
+                                (buffer-substring-no-properties 1 (point-max))
+                              (concat
+                               (buffer-substring-no-properties 1  1025)
+                               (buffer-substring-no-properties
+                                (- (point-max) 3072) (point-max)))))))
+                     (multibyte enable-multibyte-characters)
+                     (detected (detect-coding-region
+                                1 (min 16384 (point-max)))))
+                 (if coding
+                     (or (numberp (coding-system-eol-type coding))
+                         (setq coding (coding-system-change-eol-conversion
+                                       coding
+                                       (coding-system-eol-type detected))))
+                   (setq coding
+                         (or (find-new-buffer-file-coding-system detected)
+                             (let ((file-coding
+                                    (find-operation-coding-system
+                                     'insert-file-contents buffer-file-name)))
+                               (if (consp file-coding)
+                                   (setq file-coding (car file-coding))
+                                 file-coding)))))
+                 (if (or (eq coding 'no-conversion)
+                         (eq (coding-system-type coding) 5))
+                     (setq multibyte (set-buffer-multibyte nil)))
+                 (or multibyte
+                     (setq coding
+                           (coding-system-change-text-conversion
+                            coding 'raw-text)))
+                 (decode-coding-region 1 (point-max) coding)
+                 (set-buffer-file-coding-system coding))
                ;; Set the default-directory to the dir of the
                ;; superior buffer. 
                (setq default-directory
@@ -1057,7 +1095,8 @@ for this to be permanent."
                (buffer-substring start (+ start 512))
                chk (tar-header-name tokens))
              )))
-      (narrow-to-region 1 tar-header-offset))))
+      (narrow-to-region 1 tar-header-offset)
+      (tar-next-line 0))))
 
 
 (defun tar-octal-time (timeval)
@@ -1081,6 +1120,7 @@ to make your changes permanent."
   (save-excursion
   (let ((subfile (current-buffer))
        (subfile-size (buffer-size))
+       (coding buffer-file-coding-system)
        (descriptor tar-superior-descriptor))
     (set-buffer tar-superior-buffer)
     (let* ((tokens (tar-desc-tokens descriptor))
@@ -1102,6 +1142,9 @@ to make your changes permanent."
          ;; insert the new data...
          (goto-char data-start)
          (insert-buffer subfile)
+         (setq subfile-size
+               (encode-coding-region
+                data-start (+ data-start subfile-size) coding))
          ;;
          ;; pad the new data out to a multiple of 512...
          (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
@@ -1161,10 +1204,13 @@ to make your changes permanent."
        (tar-pad-to-blocksize))
        (narrow-to-region 1 tar-header-offset)))
     (set-buffer-modified-p t)   ; mark the tar file as modified
+    (tar-next-line 0)
     (set-buffer subfile)
     (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
     (message "Saved into tar-buffer `%s'.  Be sure to save that buffer!"
             (buffer-name tar-superior-buffer))
+    ;; Prevent basic-save-buffer from changing our coding-system.
+    (setq last-coding-system-used buffer-file-coding-system)
     ;; Prevent ordinary saving from happening.
     t)))