# Copyright 2010, Google Inc.

# All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions are

# met:

#

#     * Redistributions of source code must retain the above copyright

# notice, this list of conditions and the following disclaimer.

#     * Redistributions in binary form must reproduce the above

# copyright notice, this list of conditions and the following disclaimer

# in the documentation and/or other materials provided with the

# distribution.

#     * Neither the name of Google Inc. nor the names of its

# contributors may be used to endorse or promote products derived from

# this software without specific prior written permission.

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

"""Abstraction to simplify socket use for Python < 2.6

This will attempt to use the ssl module and the new

socket.create_connection method, but fall back to the old

methods if those are unavailable.

"""

import logging

import socket

logger = logging.getLogger(__name__)

try:

    import ssl

    ssl.wrap_socket  # make demandimporters load the module

    have_ssl = True

except ImportError:

    import httplib

    import urllib2

    have_ssl = getattr(urllib2, 'HTTPSHandler', False)

    ssl = False

try:

    create_connection = socket.create_connection

except AttributeError:

    def create_connection(address):

        host, port = address

        msg = "getaddrinfo returns an empty list"

        sock = None

        for res in socket.getaddrinfo(host, port, 0,

                                      socket.SOCK_STREAM):

            af, socktype, proto, _canonname, sa = res

            try:

                sock = socket.socket(af, socktype, proto)

                logger.info("connect: (%s, %s)", host, port)

                sock.connect(sa)

            except socket.error, msg:

                logger.info('connect fail: %s %s', host, port)

                if sock:

                    sock.close()

                sock = None

                continue

            break

        if not sock:

        return sock

if ssl:

    wrap_socket = ssl.wrap_socket

    CERT_NONE = ssl.CERT_NONE

    CERT_OPTIONAL = ssl.CERT_OPTIONAL

    CERT_REQUIRED = ssl.CERT_REQUIRED

else:

    class FakeSocket(httplib.FakeSocket):

        """Socket wrapper that supports SSL.

        """

        # backport the behavior from Python 2.6, which is to busy wait

        # on the socket instead of anything nice. Sigh.

        # See http://bugs.python.org/issue3890 for more info.

        def recv(self, buflen=1024, flags=0):

            """ssl-aware wrapper around socket.recv

            """

            if flags != 0:

                raise ValueError(

                    "non-zero flags not allowed in calls to recv() on %s" %

                    self.__class__)

            while True:

                try:

                    return self._ssl.read(buflen)

                except socket.sslerror, x:

                    if x.args[0] == socket.SSL_ERROR_WANT_READ:

                        continue

                    else:

                        raise x

    _PROTOCOL_SSLv23 = 2

    CERT_NONE = 0

    CERT_OPTIONAL = 1

    CERT_REQUIRED = 2

    def wrap_socket(sock, keyfile=None, certfile=None,

                server_side=False, cert_reqs=CERT_NONE,

                ssl_version=_PROTOCOL_SSLv23, ca_certs=None,

                do_handshake_on_connect=True,

                suppress_ragged_eofs=True):

        if cert_reqs != CERT_NONE and ca_certs:

            raise CertificateValidationUnsupported(

                'SSL certificate validation requires the ssl module'

                '(included in Python 2.6 and later.)')

        sslob = socket.ssl(sock)

        # borrow httplib's workaround for no ssl.wrap_socket

        sock = FakeSocket(sock, sslob)

        return sock

class CertificateValidationUnsupported(Exception):

    """Exception raised when cert validation is requested but unavailable."""

# no-check-code