(tar-file-name-handler): New function.

(tar-extract): Bind file-name-handler-alist to it to force
find-buffer-file-type-coding-system behave as if the file being extracted
existed.  Use last-coding-system-used to force buffer-file-coding-system
to what decode-coding-region actually used to decode the file.

2 files changed, 29 insertions, 4 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 3ecd84c2a98..5f8f8ef3379 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,12 @@
+2007-05-23  Eli Zaretskii  <eliz@gnu.org>
+
+        * tar-mode.el (tar-file-name-handler): New function.
+        (tar-extract): Bind file-name-handler-alist to it to force
+        find-buffer-file-type-coding-system behave as if the file being
+        extracted existed.  Use last-coding-system-used to force
+        buffer-file-coding-system to what decode-coding-region actually
+        used to decode the file.
+
 2007-05-23  Nikolaj Schumacher  <n_schumacher@web.de>  (tiny change)
 
         * progmodes/compile.el (compilation-handle-exit):
diff --git a/lisp/tar-mode.el b/lisp/tar-mode.el
index cffc8a4cccc..f5022a9fcd4 100644
--- a/lisp/tar-mode.el
+++ b/lisp/tar-mode.el
@@ -681,6 +681,12 @@ appear on disk when you save the tar-file's buffer."
   (goto-char (posn-point (event-end event)))
   (tar-extract))
 
+(defun tar-file-name-handler (op &rest args)
+  "Helper function for `tar-extract'."
+  (or (eq op 'file-exists-p)
+      (let ((file-name-handler-alist nil))
+        (apply op args))))
+
 (defun tar-extract (&optional other-window-p)
   "In Tar mode, extract this entry of the tar file into its own buffer."
   (interactive)
@@ -735,9 +741,17 @@ appear on disk when you save the tar-file's buffer."
                                   (save-excursion
                                     (funcall set-auto-coding-function
                                              name (- (point-max) (point)))))
-                             (car (find-operation-coding-system
-                                   'insert-file-contents
-                                   (cons name (current-buffer)) t))))
+                             ;; The following binding causes
+                             ;; find-buffer-file-type-coding-system
+                             ;; (defined on dos-w32.el) to act as if
+                             ;; the file being extracted existed, so
+                             ;; that the file's contents' encoding is
+                             ;; auto-detected.
+                             (let ((file-name-handler-alist
+                                    '(("" . tar-file-name-handler))))
+                               (car (find-operation-coding-system
+                                     'insert-file-contents
+                                     (cons name (current-buffer)) t)))))
                         (multibyte enable-multibyte-characters)
                         (detected (detect-coding-region
                                    (point-min)
@@ -758,7 +772,9 @@ appear on disk when you save the tar-file's buffer."
                               (coding-system-change-text-conversion
                                coding 'raw-text)))
                     (decode-coding-region (point-min) (point-max) coding)
-                    (set-buffer-file-coding-system coding))
+                    ;; Force buffer-file-coding-system to what
+                    ;; decode-coding-region actually used.
+                    (set-buffer-file-coding-system last-coding-system-used t))
                   ;; Set the default-directory to the dir of the
                   ;; superior buffer.
                   (setq default-directory