VirtualMailManager/pycompat/hashlib.py
author martin f. krafft <madduck@madduck.net>
Sun, 15 Apr 2012 17:51:00 +0200
branchv0.6.x
changeset 550 867d950ce7b7
parent 366 d6573da35b5f
child 568 14abdd04ddf5
permissions -rw-r--r--
Fix transport_maps function for non-existent domains The postfix_transport_maps function had a bug causing 2012-04-15 17:40:22 CEST LOG: statement: SELECT transport FROM postfix_transport_map('logcheck', 'domine.madduck.net'); 2012-04-15 17:40:22 CEST ERROR: query returned no rows when the domain was not in the database. This would make did be NULL and make the query fail. This patch moves the tid query until after a check for did. If the latter is NULL, the function RETURNs (rather than fails).

# -*- coding: UTF-8 -*-
# Copyright (c) 2010 - 2011, Pascal Volk
# See COPYING for distribution information.

"""
    VirtualMailManager.pycompat.hashlib

    VirtualMailManager's minimal hashlib emulation for Python 2.4

    hashlib.md5(...), hashlib.sha1(...), hashlib.new('md5', ...) and
    hashlib.new('sha1', ...) will work always.

    When the PyCrypto module <http://www.pycrypto.org/> could be found in
    sys.path hashlib.new('md4', ...) will also work.

    With PyCrypto >= 2.1.0alpha1 hashlib.new('sha256', ...) and
    hashlib.sha256(...) becomes functional.
"""


import md5 as _md5
import sha as _sha1

try:
    import Crypto
except ImportError:
    _md4 = None
    SHA256 = None
else:
    from Crypto.Hash import MD4 as _md4
    if hasattr(Crypto, 'version_info'):  # <- Available since v2.1.0alpha1
        from Crypto.Hash import SHA256   # SHA256 works since v2.1.0alpha1
        sha256 = SHA256.new
    else:
        SHA256 = None
    del Crypto


compat = 0x01
md5 = _md5.new
sha1 = _sha1.new


def new(name, string=''):
    """Return a new hashing object using the named algorithm, optionally
    initialized with the provided string.
    """
    if name in ('md5', 'MD5'):
        return _md5.new(string)
    if name in ('sha1', 'SHA1'):
        return _sha1.new(string)
    if not _md4:
        raise ValueError('unsupported hash type')
    if name in ('md4', 'MD4'):
        return _md4.new(string)
    if name in ('sha256', 'SHA256') and SHA256:
        return SHA256.new(string)
    raise ValueError('unsupported hash type')