--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_internal/utils/misc.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,886 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import contextlib
+import errno
+import getpass
+import hashlib
+import io
+import logging
+import os
+import posixpath
+import shutil
+import stat
+import sys
+from collections import deque
+
+from pip._vendor import pkg_resources
+# NOTE: retrying is not annotated in typeshed as on 2017-07-17, which is
+#       why we ignore the type on this import.
+from pip._vendor.retrying import retry  # type: ignore
+from pip._vendor.six import PY2, text_type
+from pip._vendor.six.moves import input
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.six.moves.urllib.parse import unquote as urllib_unquote
+
+from pip import __version__
+from pip._internal.exceptions import CommandError
+from pip._internal.locations import (
+    get_major_minor_version,
+    site_packages,
+    user_site,
+)
+from pip._internal.utils.compat import (
+    WINDOWS,
+    expanduser,
+    stdlib_pkgs,
+    str_to_display,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING, cast
+from pip._internal.utils.virtualenv import (
+    running_under_virtualenv,
+    virtualenv_no_global,
+)
+
+if PY2:
+    from io import BytesIO as StringIO
+else:
+    from io import StringIO
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, AnyStr, Container, Iterable, List, Optional, Text,
+        Tuple, Union,
+    )
+    from pip._vendor.pkg_resources import Distribution
+
+    VersionInfo = Tuple[int, int, int]
+
+
+__all__ = ['rmtree', 'display_path', 'backup_dir',
+           'ask', 'splitext',
+           'format_size', 'is_installable_dir',
+           'normalize_path',
+           'renames', 'get_prog',
+           'captured_stdout', 'ensure_dir',
+           'get_installed_version', 'remove_auth_from_url']
+
+
+logger = logging.getLogger(__name__)
+
+
+def get_pip_version():
+    # type: () -> str
+    pip_pkg_dir = os.path.join(os.path.dirname(__file__), "..", "..")
+    pip_pkg_dir = os.path.abspath(pip_pkg_dir)
+
+    return (
+        'pip {} from {} (python {})'.format(
+            __version__, pip_pkg_dir, get_major_minor_version(),
+        )
+    )
+
+
+def normalize_version_info(py_version_info):
+    # type: (Tuple[int, ...]) -> Tuple[int, int, int]
+    """
+    Convert a tuple of ints representing a Python version to one of length
+    three.
+
+    :param py_version_info: a tuple of ints representing a Python version,
+        or None to specify no version. The tuple can have any length.
+
+    :return: a tuple of length three if `py_version_info` is non-None.
+        Otherwise, return `py_version_info` unchanged (i.e. None).
+    """
+    if len(py_version_info) < 3:
+        py_version_info += (3 - len(py_version_info)) * (0,)
+    elif len(py_version_info) > 3:
+        py_version_info = py_version_info[:3]
+
+    return cast('VersionInfo', py_version_info)
+
+
+def ensure_dir(path):
+    # type: (AnyStr) -> None
+    """os.path.makedirs without EEXIST."""
+    try:
+        os.makedirs(path)
+    except OSError as e:
+        # Windows can raise spurious ENOTEMPTY errors. See #6426.
+        if e.errno != errno.EEXIST and e.errno != errno.ENOTEMPTY:
+            raise
+
+
+def get_prog():
+    # type: () -> str
+    try:
+        prog = os.path.basename(sys.argv[0])
+        if prog in ('__main__.py', '-c'):
+            return "%s -m pip" % sys.executable
+        else:
+            return prog
+    except (AttributeError, TypeError, IndexError):
+        pass
+    return 'pip'
+
+
+# Retry every half second for up to 3 seconds
+@retry(stop_max_delay=3000, wait_fixed=500)
+def rmtree(dir, ignore_errors=False):
+    # type: (str, bool) -> None
+    shutil.rmtree(dir, ignore_errors=ignore_errors,
+                  onerror=rmtree_errorhandler)
+
+
+def rmtree_errorhandler(func, path, exc_info):
+    """On Windows, the files in .svn are read-only, so when rmtree() tries to
+    remove them, an exception is thrown.  We catch that here, remove the
+    read-only attribute, and hopefully continue without problems."""
+    try:
+        has_attr_readonly = not (os.stat(path).st_mode & stat.S_IWRITE)
+    except (IOError, OSError):
+        # it's equivalent to os.path.exists
+        return
+
+    if has_attr_readonly:
+        # convert to read/write
+        os.chmod(path, stat.S_IWRITE)
+        # use the original function to repeat the operation
+        func(path)
+        return
+    else:
+        raise
+
+
+def path_to_display(path):
+    # type: (Optional[Union[str, Text]]) -> Optional[Text]
+    """
+    Convert a bytes (or text) path to text (unicode in Python 2) for display
+    and logging purposes.
+
+    This function should never error out. Also, this function is mainly needed
+    for Python 2 since in Python 3 str paths are already text.
+    """
+    if path is None:
+        return None
+    if isinstance(path, text_type):
+        return path
+    # Otherwise, path is a bytes object (str in Python 2).
+    try:
+        display_path = path.decode(sys.getfilesystemencoding(), 'strict')
+    except UnicodeDecodeError:
+        # Include the full bytes to make troubleshooting easier, even though
+        # it may not be very human readable.
+        if PY2:
+            # Convert the bytes to a readable str representation using
+            # repr(), and then convert the str to unicode.
+            #   Also, we add the prefix "b" to the repr() return value both
+            # to make the Python 2 output look like the Python 3 output, and
+            # to signal to the user that this is a bytes representation.
+            display_path = str_to_display('b{!r}'.format(path))
+        else:
+            # Silence the "F821 undefined name 'ascii'" flake8 error since
+            # in Python 3 ascii() is a built-in.
+            display_path = ascii(path)  # noqa: F821
+
+    return display_path
+
+
+def display_path(path):
+    # type: (Union[str, Text]) -> str
+    """Gives the display value for a given path, making it relative to cwd
+    if possible."""
+    path = os.path.normcase(os.path.abspath(path))
+    if sys.version_info[0] == 2:
+        path = path.decode(sys.getfilesystemencoding(), 'replace')
+        path = path.encode(sys.getdefaultencoding(), 'replace')
+    if path.startswith(os.getcwd() + os.path.sep):
+        path = '.' + path[len(os.getcwd()):]
+    return path
+
+
+def backup_dir(dir, ext='.bak'):
+    # type: (str, str) -> str
+    """Figure out the name of a directory to back up the given dir to
+    (adding .bak, .bak2, etc)"""
+    n = 1
+    extension = ext
+    while os.path.exists(dir + extension):
+        n += 1
+        extension = ext + str(n)
+    return dir + extension
+
+
+def ask_path_exists(message, options):
+    # type: (str, Iterable[str]) -> str
+    for action in os.environ.get('PIP_EXISTS_ACTION', '').split():
+        if action in options:
+            return action
+    return ask(message, options)
+
+
+def _check_no_input(message):
+    # type: (str) -> None
+    """Raise an error if no input is allowed."""
+    if os.environ.get('PIP_NO_INPUT'):
+        raise Exception(
+            'No input was expected ($PIP_NO_INPUT set); question: %s' %
+            message
+        )
+
+
+def ask(message, options):
+    # type: (str, Iterable[str]) -> str
+    """Ask the message interactively, with the given possible responses"""
+    while 1:
+        _check_no_input(message)
+        response = input(message)
+        response = response.strip().lower()
+        if response not in options:
+            print(
+                'Your response (%r) was not one of the expected responses: '
+                '%s' % (response, ', '.join(options))
+            )
+        else:
+            return response
+
+
+def ask_input(message):
+    # type: (str) -> str
+    """Ask for input interactively."""
+    _check_no_input(message)
+    return input(message)
+
+
+def ask_password(message):
+    # type: (str) -> str
+    """Ask for a password interactively."""
+    _check_no_input(message)
+    return getpass.getpass(message)
+
+
+def format_size(bytes):
+    # type: (float) -> str
+    if bytes > 1000 * 1000:
+        return '%.1f MB' % (bytes / 1000.0 / 1000)
+    elif bytes > 10 * 1000:
+        return '%i kB' % (bytes / 1000)
+    elif bytes > 1000:
+        return '%.1f kB' % (bytes / 1000.0)
+    else:
+        return '%i bytes' % bytes
+
+
+def is_installable_dir(path):
+    # type: (str) -> bool
+    """Is path is a directory containing setup.py or pyproject.toml?
+    """
+    if not os.path.isdir(path):
+        return False
+    setup_py = os.path.join(path, 'setup.py')
+    if os.path.isfile(setup_py):
+        return True
+    pyproject_toml = os.path.join(path, 'pyproject.toml')
+    if os.path.isfile(pyproject_toml):
+        return True
+    return False
+
+
+def read_chunks(file, size=io.DEFAULT_BUFFER_SIZE):
+    """Yield pieces of data from a file-like object until EOF."""
+    while True:
+        chunk = file.read(size)
+        if not chunk:
+            break
+        yield chunk
+
+
+def normalize_path(path, resolve_symlinks=True):
+    # type: (str, bool) -> str
+    """
+    Convert a path to its canonical, case-normalized, absolute version.
+
+    """
+    path = expanduser(path)
+    if resolve_symlinks:
+        path = os.path.realpath(path)
+    else:
+        path = os.path.abspath(path)
+    return os.path.normcase(path)
+
+
+def splitext(path):
+    # type: (str) -> Tuple[str, str]
+    """Like os.path.splitext, but take off .tar too"""
+    base, ext = posixpath.splitext(path)
+    if base.lower().endswith('.tar'):
+        ext = base[-4:] + ext
+        base = base[:-4]
+    return base, ext
+
+
+def renames(old, new):
+    # type: (str, str) -> None
+    """Like os.renames(), but handles renaming across devices."""
+    # Implementation borrowed from os.renames().
+    head, tail = os.path.split(new)
+    if head and tail and not os.path.exists(head):
+        os.makedirs(head)
+
+    shutil.move(old, new)
+
+    head, tail = os.path.split(old)
+    if head and tail:
+        try:
+            os.removedirs(head)
+        except OSError:
+            pass
+
+
+def is_local(path):
+    # type: (str) -> bool
+    """
+    Return True if path is within sys.prefix, if we're running in a virtualenv.
+
+    If we're not in a virtualenv, all paths are considered "local."
+
+    Caution: this function assumes the head of path has been normalized
+    with normalize_path.
+    """
+    if not running_under_virtualenv():
+        return True
+    return path.startswith(normalize_path(sys.prefix))
+
+
+def dist_is_local(dist):
+    # type: (Distribution) -> bool
+    """
+    Return True if given Distribution object is installed locally
+    (i.e. within current virtualenv).
+
+    Always True if we're not in a virtualenv.
+
+    """
+    return is_local(dist_location(dist))
+
+
+def dist_in_usersite(dist):
+    # type: (Distribution) -> bool
+    """
+    Return True if given Distribution is installed in user site.
+    """
+    return dist_location(dist).startswith(normalize_path(user_site))
+
+
+def dist_in_site_packages(dist):
+    # type: (Distribution) -> bool
+    """
+    Return True if given Distribution is installed in
+    sysconfig.get_python_lib().
+    """
+    return dist_location(dist).startswith(normalize_path(site_packages))
+
+
+def dist_is_editable(dist):
+    # type: (Distribution) -> bool
+    """
+    Return True if given Distribution is an editable install.
+    """
+    for path_item in sys.path:
+        egg_link = os.path.join(path_item, dist.project_name + '.egg-link')
+        if os.path.isfile(egg_link):
+            return True
+    return False
+
+
+def get_installed_distributions(
+        local_only=True,  # type: bool
+        skip=stdlib_pkgs,  # type: Container[str]
+        include_editables=True,  # type: bool
+        editables_only=False,  # type: bool
+        user_only=False,  # type: bool
+        paths=None  # type: Optional[List[str]]
+):
+    # type: (...) -> List[Distribution]
+    """
+    Return a list of installed Distribution objects.
+
+    If ``local_only`` is True (default), only return installations
+    local to the current virtualenv, if in a virtualenv.
+
+    ``skip`` argument is an iterable of lower-case project names to
+    ignore; defaults to stdlib_pkgs
+
+    If ``include_editables`` is False, don't report editables.
+
+    If ``editables_only`` is True , only report editables.
+
+    If ``user_only`` is True , only report installations in the user
+    site directory.
+
+    If ``paths`` is set, only report the distributions present at the
+    specified list of locations.
+    """
+    if paths:
+        working_set = pkg_resources.WorkingSet(paths)
+    else:
+        working_set = pkg_resources.working_set
+
+    if local_only:
+        local_test = dist_is_local
+    else:
+        def local_test(d):
+            return True
+
+    if include_editables:
+        def editable_test(d):
+            return True
+    else:
+        def editable_test(d):
+            return not dist_is_editable(d)
+
+    if editables_only:
+        def editables_only_test(d):
+            return dist_is_editable(d)
+    else:
+        def editables_only_test(d):
+            return True
+
+    if user_only:
+        user_test = dist_in_usersite
+    else:
+        def user_test(d):
+            return True
+
+    return [d for d in working_set
+            if local_test(d) and
+            d.key not in skip and
+            editable_test(d) and
+            editables_only_test(d) and
+            user_test(d)
+            ]
+
+
+def egg_link_path(dist):
+    # type: (Distribution) -> Optional[str]
+    """
+    Return the path for the .egg-link file if it exists, otherwise, None.
+
+    There's 3 scenarios:
+    1) not in a virtualenv
+       try to find in site.USER_SITE, then site_packages
+    2) in a no-global virtualenv
+       try to find in site_packages
+    3) in a yes-global virtualenv
+       try to find in site_packages, then site.USER_SITE
+       (don't look in global location)
+
+    For #1 and #3, there could be odd cases, where there's an egg-link in 2
+    locations.
+
+    This method will just return the first one found.
+    """
+    sites = []
+    if running_under_virtualenv():
+        sites.append(site_packages)
+        if not virtualenv_no_global() and user_site:
+            sites.append(user_site)
+    else:
+        if user_site:
+            sites.append(user_site)
+        sites.append(site_packages)
+
+    for site in sites:
+        egglink = os.path.join(site, dist.project_name) + '.egg-link'
+        if os.path.isfile(egglink):
+            return egglink
+    return None
+
+
+def dist_location(dist):
+    # type: (Distribution) -> str
+    """
+    Get the site-packages location of this distribution. Generally
+    this is dist.location, except in the case of develop-installed
+    packages, where dist.location is the source code location, and we
+    want to know where the egg-link file is.
+
+    The returned location is normalized (in particular, with symlinks removed).
+    """
+    egg_link = egg_link_path(dist)
+    if egg_link:
+        return normalize_path(egg_link)
+    return normalize_path(dist.location)
+
+
+def write_output(msg, *args):
+    # type: (str, str) -> None
+    logger.info(msg, *args)
+
+
+class FakeFile(object):
+    """Wrap a list of lines in an object with readline() to make
+    ConfigParser happy."""
+    def __init__(self, lines):
+        self._gen = (l for l in lines)
+
+    def readline(self):
+        try:
+            try:
+                return next(self._gen)
+            except NameError:
+                return self._gen.next()
+        except StopIteration:
+            return ''
+
+    def __iter__(self):
+        return self._gen
+
+
+class StreamWrapper(StringIO):
+
+    @classmethod
+    def from_stream(cls, orig_stream):
+        cls.orig_stream = orig_stream
+        return cls()
+
+    # compileall.compile_dir() needs stdout.encoding to print to stdout
+    @property
+    def encoding(self):
+        return self.orig_stream.encoding
+
+
+@contextlib.contextmanager
+def captured_output(stream_name):
+    """Return a context manager used by captured_stdout/stdin/stderr
+    that temporarily replaces the sys stream *stream_name* with a StringIO.
+
+    Taken from Lib/support/__init__.py in the CPython repo.
+    """
+    orig_stdout = getattr(sys, stream_name)
+    setattr(sys, stream_name, StreamWrapper.from_stream(orig_stdout))
+    try:
+        yield getattr(sys, stream_name)
+    finally:
+        setattr(sys, stream_name, orig_stdout)
+
+
+def captured_stdout():
+    """Capture the output of sys.stdout:
+
+       with captured_stdout() as stdout:
+           print('hello')
+       self.assertEqual(stdout.getvalue(), 'hello\n')
+
+    Taken from Lib/support/__init__.py in the CPython repo.
+    """
+    return captured_output('stdout')
+
+
+def captured_stderr():
+    """
+    See captured_stdout().
+    """
+    return captured_output('stderr')
+
+
+class cached_property(object):
+    """A property that is only computed once per instance and then replaces
+       itself with an ordinary attribute. Deleting the attribute resets the
+       property.
+
+       Source: https://github.com/bottlepy/bottle/blob/0.11.5/bottle.py#L175
+    """
+
+    def __init__(self, func):
+        self.__doc__ = getattr(func, '__doc__')
+        self.func = func
+
+    def __get__(self, obj, cls):
+        if obj is None:
+            # We're being accessed from the class itself, not from an object
+            return self
+        value = obj.__dict__[self.func.__name__] = self.func(obj)
+        return value
+
+
+def get_installed_version(dist_name, working_set=None):
+    """Get the installed version of dist_name avoiding pkg_resources cache"""
+    # Create a requirement that we'll look for inside of setuptools.
+    req = pkg_resources.Requirement.parse(dist_name)
+
+    if working_set is None:
+        # We want to avoid having this cached, so we need to construct a new
+        # working set each time.
+        working_set = pkg_resources.WorkingSet()
+
+    # Get the installed distribution from our working set
+    dist = working_set.find(req)
+
+    # Check to see if we got an installed distribution or not, if we did
+    # we want to return it's version.
+    return dist.version if dist else None
+
+
+def consume(iterator):
+    """Consume an iterable at C speed."""
+    deque(iterator, maxlen=0)
+
+
+# Simulates an enum
+def enum(*sequential, **named):
+    enums = dict(zip(sequential, range(len(sequential))), **named)
+    reverse = {value: key for key, value in enums.items()}
+    enums['reverse_mapping'] = reverse
+    return type('Enum', (), enums)
+
+
+def build_netloc(host, port):
+    # type: (str, Optional[int]) -> str
+    """
+    Build a netloc from a host-port pair
+    """
+    if port is None:
+        return host
+    if ':' in host:
+        # Only wrap host with square brackets when it is IPv6
+        host = '[{}]'.format(host)
+    return '{}:{}'.format(host, port)
+
+
+def build_url_from_netloc(netloc, scheme='https'):
+    # type: (str, str) -> str
+    """
+    Build a full URL from a netloc.
+    """
+    if netloc.count(':') >= 2 and '@' not in netloc and '[' not in netloc:
+        # It must be a bare IPv6 address, so wrap it with brackets.
+        netloc = '[{}]'.format(netloc)
+    return '{}://{}'.format(scheme, netloc)
+
+
+def parse_netloc(netloc):
+    # type: (str) -> Tuple[str, Optional[int]]
+    """
+    Return the host-port pair from a netloc.
+    """
+    url = build_url_from_netloc(netloc)
+    parsed = urllib_parse.urlparse(url)
+    return parsed.hostname, parsed.port
+
+
+def split_auth_from_netloc(netloc):
+    """
+    Parse out and remove the auth information from a netloc.
+
+    Returns: (netloc, (username, password)).
+    """
+    if '@' not in netloc:
+        return netloc, (None, None)
+
+    # Split from the right because that's how urllib.parse.urlsplit()
+    # behaves if more than one @ is present (which can be checked using
+    # the password attribute of urlsplit()'s return value).
+    auth, netloc = netloc.rsplit('@', 1)
+    if ':' in auth:
+        # Split from the left because that's how urllib.parse.urlsplit()
+        # behaves if more than one : is present (which again can be checked
+        # using the password attribute of the return value)
+        user_pass = auth.split(':', 1)
+    else:
+        user_pass = auth, None
+
+    user_pass = tuple(
+        None if x is None else urllib_unquote(x) for x in user_pass
+    )
+
+    return netloc, user_pass
+
+
+def redact_netloc(netloc):
+    # type: (str) -> str
+    """
+    Replace the sensitive data in a netloc with "****", if it exists.
+
+    For example:
+        - "user:pass@example.com" returns "user:****@example.com"
+        - "accesstoken@example.com" returns "****@example.com"
+    """
+    netloc, (user, password) = split_auth_from_netloc(netloc)
+    if user is None:
+        return netloc
+    if password is None:
+        user = '****'
+        password = ''
+    else:
+        user = urllib_parse.quote(user)
+        password = ':****'
+    return '{user}{password}@{netloc}'.format(user=user,
+                                              password=password,
+                                              netloc=netloc)
+
+
+def _transform_url(url, transform_netloc):
+    """Transform and replace netloc in a url.
+
+    transform_netloc is a function taking the netloc and returning a
+    tuple. The first element of this tuple is the new netloc. The
+    entire tuple is returned.
+
+    Returns a tuple containing the transformed url as item 0 and the
+    original tuple returned by transform_netloc as item 1.
+    """
+    purl = urllib_parse.urlsplit(url)
+    netloc_tuple = transform_netloc(purl.netloc)
+    # stripped url
+    url_pieces = (
+        purl.scheme, netloc_tuple[0], purl.path, purl.query, purl.fragment
+    )
+    surl = urllib_parse.urlunsplit(url_pieces)
+    return surl, netloc_tuple
+
+
+def _get_netloc(netloc):
+    return split_auth_from_netloc(netloc)
+
+
+def _redact_netloc(netloc):
+    return (redact_netloc(netloc),)
+
+
+def split_auth_netloc_from_url(url):
+    # type: (str) -> Tuple[str, str, Tuple[str, str]]
+    """
+    Parse a url into separate netloc, auth, and url with no auth.
+
+    Returns: (url_without_auth, netloc, (username, password))
+    """
+    url_without_auth, (netloc, auth) = _transform_url(url, _get_netloc)
+    return url_without_auth, netloc, auth
+
+
+def remove_auth_from_url(url):
+    # type: (str) -> str
+    """Return a copy of url with 'username:password@' removed."""
+    # username/pass params are passed to subversion through flags
+    # and are not recognized in the url.
+    return _transform_url(url, _get_netloc)[0]
+
+
+def redact_auth_from_url(url):
+    # type: (str) -> str
+    """Replace the password in a given url with ****."""
+    return _transform_url(url, _redact_netloc)[0]
+
+
+class HiddenText(object):
+    def __init__(
+        self,
+        secret,    # type: str
+        redacted,  # type: str
+    ):
+        # type: (...) -> None
+        self.secret = secret
+        self.redacted = redacted
+
+    def __repr__(self):
+        # type: (...) -> str
+        return '<HiddenText {!r}>'.format(str(self))
+
+    def __str__(self):
+        # type: (...) -> str
+        return self.redacted
+
+    # This is useful for testing.
+    def __eq__(self, other):
+        # type: (Any) -> bool
+        if type(self) != type(other):
+            return False
+
+        # The string being used for redaction doesn't also have to match,
+        # just the raw, original string.
+        return (self.secret == other.secret)
+
+    # We need to provide an explicit __ne__ implementation for Python 2.
+    # TODO: remove this when we drop PY2 support.
+    def __ne__(self, other):
+        # type: (Any) -> bool
+        return not self == other
+
+
+def hide_value(value):
+    # type: (str) -> HiddenText
+    return HiddenText(value, redacted='****')
+
+
+def hide_url(url):
+    # type: (str) -> HiddenText
+    redacted = redact_auth_from_url(url)
+    return HiddenText(url, redacted=redacted)
+
+
+def protect_pip_from_modification_on_windows(modifying_pip):
+    # type: (bool) -> None
+    """Protection of pip.exe from modification on Windows
+
+    On Windows, any operation modifying pip should be run as:
+        python -m pip ...
+    """
+    pip_names = [
+        "pip.exe",
+        "pip{}.exe".format(sys.version_info[0]),
+        "pip{}.{}.exe".format(*sys.version_info[:2])
+    ]
+
+    # See https://github.com/pypa/pip/issues/1299 for more discussion
+    should_show_use_python_msg = (
+        modifying_pip and
+        WINDOWS and
+        os.path.basename(sys.argv[0]) in pip_names
+    )
+
+    if should_show_use_python_msg:
+        new_command = [
+            sys.executable, "-m", "pip"
+        ] + sys.argv[1:]
+        raise CommandError(
+            'To modify pip, please run the following command:\n{}'
+            .format(" ".join(new_command))
+        )
+
+
+def is_console_interactive():
+    # type: () -> bool
+    """Is this console interactive?
+    """
+    return sys.stdin is not None and sys.stdin.isatty()
+
+
+def hash_file(path, blocksize=1 << 20):
+    # type: (str, int) -> Tuple[Any, int]
+    """Return (hash, length) for path using hashlib.sha256()
+    """
+
+    h = hashlib.sha256()
+    length = 0
+    with open(path, 'rb') as f:
+        for block in read_chunks(f, size=blocksize):
+            length += len(block)
+            h.update(block)
+    return h, length
+
+
+def is_wheel_installed():
+    """
+    Return whether the wheel package is installed.
+    """
+    try:
+        import wheel  # noqa: F401
+    except ImportError:
+        return False
+
+    return True