Method _create_header

Lib/tarfile.py:1157–1196

Return a header block. info is a dictionary with file information, format must be one of the *_FORMAT constants.

(info, format, encoding, errors)

    @staticmethod
    def _create_header(info, format, encoding, errors):
        """Return a header block. info is a dictionary with file
           information, format must be one of the *_FORMAT constants.
        """
        has_device_fields = info.get("type") in (CHRTYPE, BLKTYPE)
        if has_device_fields:
            devmajor = itn(info.get("devmajor", 0), 8, format)
            devminor = itn(info.get("devminor", 0), 8, format)
        else:
            devmajor = stn("", 8, encoding, errors)
            devminor = stn("", 8, encoding, errors)

        # None values in metadata should cause ValueError.
        # itn()/stn() do this for all fields except type.
        filetype = info.get("type", REGTYPE)
        if filetype is None:
            raise ValueError("TarInfo.type must not be None")

        parts = [
            stn(info.get("name", ""), 100, encoding, errors),
            itn(info.get("mode", 0) & 0o7777, 8, format),
            itn(info.get("uid", 0), 8, format),
            itn(info.get("gid", 0), 8, format),
            itn(info.get("size", 0), 12, format),
            itn(info.get("mtime", 0), 12, format),
            b"        ", # checksum field
            filetype,
            stn(info.get("linkname", ""), 100, encoding, errors),
            info.get("magic", POSIX_MAGIC),
            stn(info.get("uname", ""), 32, encoding, errors),
            stn(info.get("gname", ""), 32, encoding, errors),
            devmajor,
            devminor,
            stn(info.get("prefix", ""), 155, encoding, errors)
        ]

        buf = struct.pack("%ds" % BLOCKSIZE, b"".join(parts))
        chksum = calc_chksums(buf[-BLOCKSIZE:])[0]
        buf = buf[:-364] + bytes("%06o\0" % chksum, "ascii") + buf[-357:]
        return buf

    @staticmethod
    def _create_payload(payload):