diff-find-file-name

diff-find-file-name is a compiled Lisp function in `diff-mode.el'.

(diff-find-file-name &optional OLD NOPROMPT PREFIX)

Return the file corresponding to the current patch.
Non-nil OLD means that we want the old file.
Non-nil NOPROMPT means to prefer returning nil than to prompt the user.
PREFIX is only used internally: don't use it.