Return the dst filepath from the src URI.

        Returns None on failure, destination path on success.

def src_to_dst(self, src_uri):
        """Return the dst filepath from the src URI.

        Returns None on failure, destination path on success.
        """
        m = re.match(self.src_uri + "/(.*)$", src_uri)
        if (m is None):
            return(None)
        rel_path = m.group(1)
        return(self.dst_path + '/' + rel_path)