mercurial/httpclient/socketutil.py

largefiles: handle merges between normal files and largefiles (issue3084)

The largefiles extension prevents users from adding a normal file
named 'foo' if there is already a largefile with the same name.
However, there was a loop-hole: when merging, it was possible to bring
in a normal file named 'foo' while also having a '.hglf/foo' file.

This patch fixes this by extending the manifest merge to deal with
these kinds of conflicts. If there is a normal file 'foo' in the
working copy, and the other parent brings in a '.hglf/foo' file, then
the user will be prompted to keep the normal file or the largefile.
Likewise for the symmetric case where a normal file is brought in via
the second parent. The prompt looks like this:

  $ hg merge
  foo has been turned into a largefile
  use (l)argefile or keep as (n)ormal file?

After the merge, either the '.hglf/foo' file or the 'foo' file will
have been deleted. This would cause status to return output like:

  $ hg status
  M foo
  R foo

To fix this, the lfiles_repo.status method is changed so that a
removed normal file isn't shown if there is largefile with the same
name, and vice versa for largefiles.

# Copyright 2010, Google Inc.
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"""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:
            raise socket.error, msg
        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