file-hist.el

(defun git-file-history ()
  (interactive)
  (let (
        (diff-history-buffer (get-buffer-create "*git history*"))
        (d default-directory)
        (old-buffer-file-name (buffer-file-name))
        )
    (switch-to-buffer diff-history-buffer)
    (diff-mode)
    (setq default-directory d)
    (message old-buffer-file-name)
    (start-process "githist" diff-history-buffer "git" "--no-pager" "log" "-p" old-buffer-file-name)))