Function: tar-subfile-save-buffer

tar-subfile-save-buffer is an interactive and byte-compiled function defined in tar-mode.el.gz.

Signature

(tar-subfile-save-buffer)

Documentation

In tar subfile mode, save this buffer into its parent tar-file buffer.

This doesn't write anything to disk; you must save the parent tar-file buffer to make your changes permanent.

Key Bindings

Source Code

;; Defined in /usr/src/emacs/lisp/tar-mode.el.gz
(defun tar-subfile-save-buffer ()
  "In tar subfile mode, save this buffer into its parent tar-file buffer.
This doesn't write anything to disk; you must save the parent tar-file buffer
to make your changes permanent."
  (interactive)
  (if (not (and (boundp 'tar-superior-buffer) tar-superior-buffer))
      (error "This buffer has no superior tar file buffer"))
  (if (not (and (boundp 'tar-superior-descriptor) tar-superior-descriptor))
      (error "This buffer doesn't have an index into its superior tar file!"))
  (unless (buffer-live-p tar-superior-buffer)
    (error "The tar buffer no longer exists; can't save"))
  (let ((subfile (current-buffer))
        (coding buffer-file-coding-system)
        (descriptor tar-superior-descriptor)
        subfile-size)
    (with-current-buffer tar-superior-buffer
      (let* ((start (tar-header-data-start descriptor))
             (size (tar-header-size descriptor))
             (head (memq descriptor tar-parse-info)))
        (if (not head)
            (error "Can't find this tar file entry in its parent tar file!"))
        (with-current-buffer tar-data-buffer
          ;; delete the old data...
          (let* ((data-start start)
                 (data-end (+ data-start (tar-roundup-512 size))))
            (narrow-to-region data-start data-end)
            (delete-region (point-min) (point-max))
            ;; insert the new data...
            (goto-char data-start)
            (let ((dest (current-buffer)))
              (with-current-buffer subfile
                (save-restriction
                  (widen)
                  (encode-coding-region (point-min) (point-max) coding dest))))
            (setq subfile-size (- (point-max) (point-min)))
            ;;
            ;; pad the new data out to a multiple of 512...
            (let ((subfile-size-pad (tar-roundup-512 subfile-size)))
              (goto-char (point-max))
              (insert (make-string (- subfile-size-pad subfile-size) 0))
              ;;
              ;; update the data of this files...
              (setf (tar-header-size descriptor) subfile-size)
              ;;
              ;; Update the size field in the header block.
              (widen))))
        ;;
        ;; alter the descriptor-line and header
        ;;
        (let ((position (- (length tar-parse-info) (length head))))
          (goto-char (point-min))
          (forward-line position)
	  (tar-alter-one-field tar-size-offset (format "%11o " subfile-size))
	  ;;
	  ;; Maybe update the datestamp.
	  (when tar-update-datestamp
	    (tar-alter-one-field tar-time-offset
				 (concat (tar-octal-time nil) " "))))
        ;; After doing the insertion, add any necessary final padding.
        (tar-pad-to-blocksize))
      (set-buffer-modified-p t)         ; mark the tar file as modified
      (tar-next-line 0))
    (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))