--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/pip/_internal/utils/misc.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,1201 @@
+from __future__ import absolute_import
+
+import contextlib
+import errno
+import getpass
+import io
+# we have a submodule named 'logging' which would shadow this if we used the
+# regular name:
+import logging as std_logging
+import os
+import posixpath
+import re
+import shutil
+import stat
+import subprocess
+import sys
+import tarfile
+import zipfile
+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, shlex_quote
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.six.moves.urllib import request as urllib_request
+from pip._vendor.six.moves.urllib.parse import unquote as urllib_unquote
+
+from pip import __version__
+from pip._internal.exceptions import CommandError, InstallationError
+from pip._internal.locations import site_packages, user_site
+from pip._internal.utils.compat import (
+    WINDOWS, console_to_str, expanduser, stdlib_pkgs, str_to_display,
+)
+from pip._internal.utils.marker_files import write_delete_marker_file
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+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, Mapping, Match, Optional, Text,
+        Tuple, Union, cast,
+    )
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.models.link import Link
+    from pip._internal.utils.ui import SpinnerInterface
+
+    VersionInfo = Tuple[int, int, int]
+else:
+    # typing's cast() is needed at runtime, but we don't want to import typing.
+    # Thus, we use a dummy no-op version, which we tell mypy to ignore.
+    def cast(type_, value):  # type: ignore
+        return value
+
+
+__all__ = ['rmtree', 'display_path', 'backup_dir',
+           'ask', 'splitext',
+           'format_size', 'is_installable_dir',
+           'is_svn_page', 'file_contents',
+           'split_leading_dir', 'has_leading_dir',
+           'normalize_path',
+           'renames', 'get_prog',
+           'unzip_file', 'untar_file', 'unpack_file', 'call_subprocess',
+           'captured_stdout', 'ensure_dir',
+           'ARCHIVE_EXTENSIONS', 'SUPPORTED_EXTENSIONS', 'WHEEL_EXTENSION',
+           'get_installed_version', 'remove_auth_from_url']
+
+
+logger = std_logging.getLogger(__name__)
+subprocess_logger = std_logging.getLogger('pip.subprocessor')
+
+LOG_DIVIDER = '----------------------------------------'
+
+WHEEL_EXTENSION = '.whl'
+BZ2_EXTENSIONS = ('.tar.bz2', '.tbz')
+XZ_EXTENSIONS = ('.tar.xz', '.txz', '.tlz', '.tar.lz', '.tar.lzma')
+ZIP_EXTENSIONS = ('.zip', WHEEL_EXTENSION)
+TAR_EXTENSIONS = ('.tar.gz', '.tgz', '.tar')
+ARCHIVE_EXTENSIONS = (
+    ZIP_EXTENSIONS + BZ2_EXTENSIONS + TAR_EXTENSIONS + XZ_EXTENSIONS)
+SUPPORTED_EXTENSIONS = ZIP_EXTENSIONS + TAR_EXTENSIONS
+
+try:
+    import bz2  # noqa
+    SUPPORTED_EXTENSIONS += BZ2_EXTENSIONS
+except ImportError:
+    logger.debug('bz2 module is not available')
+
+try:
+    # Only for Python 3.3+
+    import lzma  # noqa
+    SUPPORTED_EXTENSIONS += XZ_EXTENSIONS
+except ImportError:
+    logger.debug('lzma module is not available')
+
+
+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, sys.version[:3],
+        )
+    )
+
+
+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:
+        if e.errno != errno.EEXIST:
+            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."""
+    # if file type currently read only
+    if os.stat(path).st_mode & stat.S_IREAD:
+        # 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 '%.1fMB' % (bytes / 1000.0 / 1000)
+    elif bytes > 10 * 1000:
+        return '%ikB' % (bytes / 1000)
+    elif bytes > 1000:
+        return '%.1fkB' % (bytes / 1000.0)
+    else:
+        return '%ibytes' % 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 is_svn_page(html):
+    # type: (Union[str, Text]) -> Optional[Match[Union[str, Text]]]
+    """
+    Returns true if the page appears to be the index page of an svn repository
+    """
+    return (re.search(r'<title>[^<]*Revision \d+:', html) and
+            re.search(r'Powered by (?:<a[^>]*?>)?Subversion', html, re.I))
+
+
+def file_contents(filename):
+    # type: (str) -> Text
+    with open(filename, 'rb') as fp:
+        return fp.read().decode('utf-8')
+
+
+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 split_leading_dir(path):
+    # type: (Union[str, Text]) -> List[Union[str, Text]]
+    path = path.lstrip('/').lstrip('\\')
+    if '/' in path and (('\\' in path and path.find('/') < path.find('\\')) or
+                        '\\' not in path):
+        return path.split('/', 1)
+    elif '\\' in path:
+        return path.split('\\', 1)
+    else:
+        return [path, '']
+
+
+def has_leading_dir(paths):
+    # type: (Iterable[Union[str, Text]]) -> bool
+    """Returns true if all the paths have the same leading path name
+    (i.e., everything is in one subdirectory in an archive)"""
+    common_prefix = None
+    for path in paths:
+        prefix, rest = split_leading_dir(path)
+        if not prefix:
+            return False
+        elif common_prefix is None:
+            common_prefix = prefix
+        elif prefix != common_prefix:
+            return False
+    return True
+
+
+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."
+
+    """
+    if not running_under_virtualenv():
+        return True
+    return normalize_path(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.
+    """
+    norm_path = normalize_path(dist_location(dist))
+    return norm_path.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 normalize_path(
+        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
+
+    # because of pkg_resources vendoring, mypy cannot find stub in typeshed
+    return [d for d in working_set  # type: ignore
+            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():
+        if virtualenv_no_global():
+            sites.append(site_packages)
+        else:
+            sites.append(site_packages)
+            if 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.
+
+    """
+    egg_link = egg_link_path(dist)
+    if egg_link:
+        return egg_link
+    return dist.location
+
+
+def current_umask():
+    """Get the current umask which involves having to set it temporarily."""
+    mask = os.umask(0)
+    os.umask(mask)
+    return mask
+
+
+def unzip_file(filename, location, flatten=True):
+    # type: (str, str, bool) -> None
+    """
+    Unzip the file (with path `filename`) to the destination `location`.  All
+    files are written based on system defaults and umask (i.e. permissions are
+    not preserved), except that regular file members with any execute
+    permissions (user, group, or world) have "chmod +x" applied after being
+    written. Note that for windows, any execute changes using os.chmod are
+    no-ops per the python docs.
+    """
+    ensure_dir(location)
+    zipfp = open(filename, 'rb')
+    try:
+        zip = zipfile.ZipFile(zipfp, allowZip64=True)
+        leading = has_leading_dir(zip.namelist()) and flatten
+        for info in zip.infolist():
+            name = info.filename
+            fn = name
+            if leading:
+                fn = split_leading_dir(name)[1]
+            fn = os.path.join(location, fn)
+            dir = os.path.dirname(fn)
+            if fn.endswith('/') or fn.endswith('\\'):
+                # A directory
+                ensure_dir(fn)
+            else:
+                ensure_dir(dir)
+                # Don't use read() to avoid allocating an arbitrarily large
+                # chunk of memory for the file's content
+                fp = zip.open(name)
+                try:
+                    with open(fn, 'wb') as destfp:
+                        shutil.copyfileobj(fp, destfp)
+                finally:
+                    fp.close()
+                    mode = info.external_attr >> 16
+                    # if mode and regular file and any execute permissions for
+                    # user/group/world?
+                    if mode and stat.S_ISREG(mode) and mode & 0o111:
+                        # make dest file have execute for user/group/world
+                        # (chmod +x) no-op on windows per python docs
+                        os.chmod(fn, (0o777 - current_umask() | 0o111))
+    finally:
+        zipfp.close()
+
+
+def untar_file(filename, location):
+    # type: (str, str) -> None
+    """
+    Untar the file (with path `filename`) to the destination `location`.
+    All files are written based on system defaults and umask (i.e. permissions
+    are not preserved), except that regular file members with any execute
+    permissions (user, group, or world) have "chmod +x" applied after being
+    written.  Note that for windows, any execute changes using os.chmod are
+    no-ops per the python docs.
+    """
+    ensure_dir(location)
+    if filename.lower().endswith('.gz') or filename.lower().endswith('.tgz'):
+        mode = 'r:gz'
+    elif filename.lower().endswith(BZ2_EXTENSIONS):
+        mode = 'r:bz2'
+    elif filename.lower().endswith(XZ_EXTENSIONS):
+        mode = 'r:xz'
+    elif filename.lower().endswith('.tar'):
+        mode = 'r'
+    else:
+        logger.warning(
+            'Cannot determine compression type for file %s', filename,
+        )
+        mode = 'r:*'
+    tar = tarfile.open(filename, mode)
+    try:
+        leading = has_leading_dir([
+            member.name for member in tar.getmembers()
+        ])
+        for member in tar.getmembers():
+            fn = member.name
+            if leading:
+                # https://github.com/python/mypy/issues/1174
+                fn = split_leading_dir(fn)[1]  # type: ignore
+            path = os.path.join(location, fn)
+            if member.isdir():
+                ensure_dir(path)
+            elif member.issym():
+                try:
+                    # https://github.com/python/typeshed/issues/2673
+                    tar._extract_member(member, path)  # type: ignore
+                except Exception as exc:
+                    # Some corrupt tar files seem to produce this
+                    # (specifically bad symlinks)
+                    logger.warning(
+                        'In the tar file %s the member %s is invalid: %s',
+                        filename, member.name, exc,
+                    )
+                    continue
+            else:
+                try:
+                    fp = tar.extractfile(member)
+                except (KeyError, AttributeError) as exc:
+                    # Some corrupt tar files seem to produce this
+                    # (specifically bad symlinks)
+                    logger.warning(
+                        'In the tar file %s the member %s is invalid: %s',
+                        filename, member.name, exc,
+                    )
+                    continue
+                ensure_dir(os.path.dirname(path))
+                with open(path, 'wb') as destfp:
+                    shutil.copyfileobj(fp, destfp)
+                fp.close()
+                # Update the timestamp (useful for cython compiled files)
+                # https://github.com/python/typeshed/issues/2673
+                tar.utime(member, path)  # type: ignore
+                # member have any execute permissions for user/group/world?
+                if member.mode & 0o111:
+                    # make dest file have execute for user/group/world
+                    # no-op on windows per python docs
+                    os.chmod(path, (0o777 - current_umask() | 0o111))
+    finally:
+        tar.close()
+
+
+def unpack_file(
+    filename,  # type: str
+    location,  # type: str
+    content_type,  # type: Optional[str]
+    link  # type: Optional[Link]
+):
+    # type: (...) -> None
+    filename = os.path.realpath(filename)
+    if (content_type == 'application/zip' or
+            filename.lower().endswith(ZIP_EXTENSIONS) or
+            zipfile.is_zipfile(filename)):
+        unzip_file(
+            filename,
+            location,
+            flatten=not filename.endswith('.whl')
+        )
+    elif (content_type == 'application/x-gzip' or
+            tarfile.is_tarfile(filename) or
+            filename.lower().endswith(
+                TAR_EXTENSIONS + BZ2_EXTENSIONS + XZ_EXTENSIONS)):
+        untar_file(filename, location)
+    elif (content_type and content_type.startswith('text/html') and
+            is_svn_page(file_contents(filename))):
+        # We don't really care about this
+        from pip._internal.vcs.subversion import Subversion
+        url = 'svn+' + link.url
+        Subversion().unpack(location, url=url)
+    else:
+        # FIXME: handle?
+        # FIXME: magic signatures?
+        logger.critical(
+            'Cannot unpack file %s (downloaded from %s, content-type: %s); '
+            'cannot detect archive format',
+            filename, location, content_type,
+        )
+        raise InstallationError(
+            'Cannot determine archive format of %s' % location
+        )
+
+
+def format_command_args(args):
+    # type: (List[str]) -> str
+    """
+    Format command arguments for display.
+    """
+    return ' '.join(shlex_quote(arg) for arg in args)
+
+
+def make_subprocess_output_error(
+    cmd_args,     # type: List[str]
+    cwd,          # type: Optional[str]
+    lines,        # type: List[Text]
+    exit_status,  # type: int
+):
+    # type: (...) -> Text
+    """
+    Create and return the error message to use to log a subprocess error
+    with command output.
+
+    :param lines: A list of lines, each ending with a newline.
+    """
+    command = format_command_args(cmd_args)
+    # Convert `command` and `cwd` to text (unicode in Python 2) so we can use
+    # them as arguments in the unicode format string below. This avoids
+    # "UnicodeDecodeError: 'ascii' codec can't decode byte ..." in Python 2
+    # if either contains a non-ascii character.
+    command_display = str_to_display(command, desc='command bytes')
+    cwd_display = path_to_display(cwd)
+
+    # We know the joined output value ends in a newline.
+    output = ''.join(lines)
+    msg = (
+        # Use a unicode string to avoid "UnicodeEncodeError: 'ascii'
+        # codec can't encode character ..." in Python 2 when a format
+        # argument (e.g. `output`) has a non-ascii character.
+        u'Command errored out with exit status {exit_status}:\n'
+        ' command: {command_display}\n'
+        '     cwd: {cwd_display}\n'
+        'Complete output ({line_count} lines):\n{output}{divider}'
+    ).format(
+        exit_status=exit_status,
+        command_display=command_display,
+        cwd_display=cwd_display,
+        line_count=len(lines),
+        output=output,
+        divider=LOG_DIVIDER,
+    )
+    return msg
+
+
+def call_subprocess(
+    cmd,  # type: List[str]
+    show_stdout=False,  # type: bool
+    cwd=None,  # type: Optional[str]
+    on_returncode='raise',  # type: str
+    extra_ok_returncodes=None,  # type: Optional[Iterable[int]]
+    command_desc=None,  # type: Optional[str]
+    extra_environ=None,  # type: Optional[Mapping[str, Any]]
+    unset_environ=None,  # type: Optional[Iterable[str]]
+    spinner=None  # type: Optional[SpinnerInterface]
+):
+    # type: (...) -> Text
+    """
+    Args:
+      show_stdout: if true, use INFO to log the subprocess's stderr and
+        stdout streams.  Otherwise, use DEBUG.  Defaults to False.
+      extra_ok_returncodes: an iterable of integer return codes that are
+        acceptable, in addition to 0. Defaults to None, which means [].
+      unset_environ: an iterable of environment variable names to unset
+        prior to calling subprocess.Popen().
+    """
+    if extra_ok_returncodes is None:
+        extra_ok_returncodes = []
+    if unset_environ is None:
+        unset_environ = []
+    # Most places in pip use show_stdout=False. What this means is--
+    #
+    # - We connect the child's output (combined stderr and stdout) to a
+    #   single pipe, which we read.
+    # - We log this output to stderr at DEBUG level as it is received.
+    # - If DEBUG logging isn't enabled (e.g. if --verbose logging wasn't
+    #   requested), then we show a spinner so the user can still see the
+    #   subprocess is in progress.
+    # - If the subprocess exits with an error, we log the output to stderr
+    #   at ERROR level if it hasn't already been displayed to the console
+    #   (e.g. if --verbose logging wasn't enabled).  This way we don't log
+    #   the output to the console twice.
+    #
+    # If show_stdout=True, then the above is still done, but with DEBUG
+    # replaced by INFO.
+    if show_stdout:
+        # Then log the subprocess output at INFO level.
+        log_subprocess = subprocess_logger.info
+        used_level = std_logging.INFO
+    else:
+        # Then log the subprocess output using DEBUG.  This also ensures
+        # it will be logged to the log file (aka user_log), if enabled.
+        log_subprocess = subprocess_logger.debug
+        used_level = std_logging.DEBUG
+
+    # Whether the subprocess will be visible in the console.
+    showing_subprocess = subprocess_logger.getEffectiveLevel() <= used_level
+
+    # Only use the spinner if we're not showing the subprocess output
+    # and we have a spinner.
+    use_spinner = not showing_subprocess and spinner is not None
+
+    if command_desc is None:
+        command_desc = format_command_args(cmd)
+
+    log_subprocess("Running command %s", command_desc)
+    env = os.environ.copy()
+    if extra_environ:
+        env.update(extra_environ)
+    for name in unset_environ:
+        env.pop(name, None)
+    try:
+        proc = subprocess.Popen(
+            cmd, stderr=subprocess.STDOUT, stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE, cwd=cwd, env=env,
+        )
+        proc.stdin.close()
+    except Exception as exc:
+        subprocess_logger.critical(
+            "Error %s while executing command %s", exc, command_desc,
+        )
+        raise
+    all_output = []
+    while True:
+        # The "line" value is a unicode string in Python 2.
+        line = console_to_str(proc.stdout.readline())
+        if not line:
+            break
+        line = line.rstrip()
+        all_output.append(line + '\n')
+
+        # Show the line immediately.
+        log_subprocess(line)
+        # Update the spinner.
+        if use_spinner:
+            spinner.spin()
+    try:
+        proc.wait()
+    finally:
+        if proc.stdout:
+            proc.stdout.close()
+    proc_had_error = (
+        proc.returncode and proc.returncode not in extra_ok_returncodes
+    )
+    if use_spinner:
+        if proc_had_error:
+            spinner.finish("error")
+        else:
+            spinner.finish("done")
+    if proc_had_error:
+        if on_returncode == 'raise':
+            if not showing_subprocess:
+                # Then the subprocess streams haven't been logged to the
+                # console yet.
+                msg = make_subprocess_output_error(
+                    cmd_args=cmd,
+                    cwd=cwd,
+                    lines=all_output,
+                    exit_status=proc.returncode,
+                )
+                subprocess_logger.error(msg)
+            exc_msg = (
+                'Command errored out with exit status {}: {} '
+                'Check the logs for full command output.'
+            ).format(proc.returncode, command_desc)
+            raise InstallationError(exc_msg)
+        elif on_returncode == 'warn':
+            subprocess_logger.warning(
+                'Command "%s" had error code %s in %s',
+                command_desc, proc.returncode, cwd,
+            )
+        elif on_returncode == 'ignore':
+            pass
+        else:
+            raise ValueError('Invalid value: on_returncode=%s' %
+                             repr(on_returncode))
+    return ''.join(all_output)
+
+
+def _make_build_dir(build_dir):
+    os.makedirs(build_dir)
+    write_delete_marker_file(build_dir)
+
+
+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 path_to_url(path):
+    # type: (Union[str, Text]) -> str
+    """
+    Convert a path to a file: URL.  The path will be made absolute and have
+    quoted path parts.
+    """
+    path = os.path.normpath(os.path.abspath(path))
+    url = urllib_parse.urljoin('file:', urllib_request.pathname2url(path))
+    return url
+
+
+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 password in a netloc with "****", if it exists.
+
+    For example, "user:pass@example.com" returns "user:****@example.com".
+    """
+    netloc, (user, password) = split_auth_from_netloc(netloc)
+    if user is None:
+        return netloc
+    password = '' if password is None else ':****'
+    return '{user}{password}@{netloc}'.format(user=urllib_parse.quote(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_password_from_url(url):
+    # type: (str) -> str
+    """Replace the password in a given url with ****."""
+    return _transform_url(url, _redact_netloc)[0]
+
+
+def protect_pip_from_modification_on_windows(modifying_pip):
+    """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))
+        )