#!/usr/bin/python
#
# CDDL HEADER START
#
# The contents of this file are subject to the terms of the
# Common Development and Distribution License (the "License").
# You may not use this file except in compliance with the License.
#
# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
# or http://www.opensolaris.org/os/licensing.
# See the License for the specific language governing permissions
# and limitations under the License.
#
# When distributing Covered Code, include this CDDL HEADER in each
# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
# If applicable, add the following below this CDDL HEADER, with the
# fields enclosed by brackets "[]" replaced with your own identifying
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# CDDL HEADER END
#
#
# Copyright (c) 2008, 2016, Oracle and/or its affiliates. All rights reserved.
#
#ident "%Z%%M% %I% %E% SMI"
import gzip
class PkgGzipFile(gzip.GzipFile):
"""This is a version of GzipFile that does not include a file
pathname or timestamp in the gzip header. This allows us to get
deterministic gzip files on compression, so that we can reliably
use a cryptographic hash on the compressed content."""
def __init__(self, filename=None, mode=None, compresslevel=9,
fileobj=None):
gzip.GzipFile.__init__(self, filename, mode, compresslevel,
fileobj)
#
# This is a gzip header conforming to RFC1952. The first two bytes
# (\037,\213) are the gzip magic number. The third byte is the
# compression method (8, deflate). The fourth byte is the flag byte
# (0), which indicates that no FNAME, FCOMMENT or other extended data
# is present. Bytes 5-8 are the MTIME field, zeroed in this case.
# Byte 9 is the XFL (Extra Flags) field, set to 2 (compressor used
# max compression). The final bit is the OS type, set to 255 (for
# "unknown").
magic = b"\037\213\010\000\000\000\000\000\002\377"
def _write_gzip_header(self):
self.fileobj.write(self.magic)
@staticmethod
def test_is_pkggzipfile(path):
f = open(path, "rb")
hdrstr = f.read(len(PkgGzipFile.magic))
f.close()
return (hdrstr == PkgGzipFile.magic)