--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/setuptools/package_index.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,1140 @@
+"""PyPI and direct package downloading"""
+import sys
+import os
+import re
+import shutil
+import socket
+import base64
+import hashlib
+import itertools
+import warnings
+from functools import wraps
+
+from setuptools.extern import six
+from setuptools.extern.six.moves import urllib, http_client, configparser, map
+
+import setuptools
+from pkg_resources import (
+    CHECKOUT_DIST, Distribution, BINARY_DIST, normalize_path, SOURCE_DIST,
+    Environment, find_distributions, safe_name, safe_version,
+    to_filename, Requirement, DEVELOP_DIST, EGG_DIST,
+)
+from setuptools import ssl_support
+from distutils import log
+from distutils.errors import DistutilsError
+from fnmatch import translate
+from setuptools.py27compat import get_all_headers
+from setuptools.py33compat import unescape
+from setuptools.wheel import Wheel
+
+__metaclass__ = type
+
+EGG_FRAGMENT = re.compile(r'^egg=([-A-Za-z0-9_.+!]+)$')
+HREF = re.compile(r"""href\s*=\s*['"]?([^'"> ]+)""", re.I)
+PYPI_MD5 = re.compile(
+    r'<a href="([^"#]+)">([^<]+)</a>\n\s+\(<a (?:title="MD5 hash"\n\s+)'
+    r'href="[^?]+\?:action=show_md5&amp;digest=([0-9a-f]{32})">md5</a>\)'
+)
+URL_SCHEME = re.compile('([-+.a-z0-9]{2,}):', re.I).match
+EXTENSIONS = ".tar.gz .tar.bz2 .tar .zip .tgz".split()
+
+__all__ = [
+    'PackageIndex', 'distros_for_url', 'parse_bdist_wininst',
+    'interpret_distro_name',
+]
+
+_SOCKET_TIMEOUT = 15
+
+_tmpl = "setuptools/{setuptools.__version__} Python-urllib/{py_major}"
+user_agent = _tmpl.format(
+    py_major='{}.{}'.format(*sys.version_info), setuptools=setuptools)
+
+
+def parse_requirement_arg(spec):
+    try:
+        return Requirement.parse(spec)
+    except ValueError:
+        raise DistutilsError(
+            "Not a URL, existing file, or requirement spec: %r" % (spec,)
+        )
+
+
+def parse_bdist_wininst(name):
+    """Return (base,pyversion) or (None,None) for possible .exe name"""
+
+    lower = name.lower()
+    base, py_ver, plat = None, None, None
+
+    if lower.endswith('.exe'):
+        if lower.endswith('.win32.exe'):
+            base = name[:-10]
+            plat = 'win32'
+        elif lower.startswith('.win32-py', -16):
+            py_ver = name[-7:-4]
+            base = name[:-16]
+            plat = 'win32'
+        elif lower.endswith('.win-amd64.exe'):
+            base = name[:-14]
+            plat = 'win-amd64'
+        elif lower.startswith('.win-amd64-py', -20):
+            py_ver = name[-7:-4]
+            base = name[:-20]
+            plat = 'win-amd64'
+    return base, py_ver, plat
+
+
+def egg_info_for_url(url):
+    parts = urllib.parse.urlparse(url)
+    scheme, server, path, parameters, query, fragment = parts
+    base = urllib.parse.unquote(path.split('/')[-1])
+    if server == 'sourceforge.net' and base == 'download':  # XXX Yuck
+        base = urllib.parse.unquote(path.split('/')[-2])
+    if '#' in base:
+        base, fragment = base.split('#', 1)
+    return base, fragment
+
+
+def distros_for_url(url, metadata=None):
+    """Yield egg or source distribution objects that might be found at a URL"""
+    base, fragment = egg_info_for_url(url)
+    for dist in distros_for_location(url, base, metadata):
+        yield dist
+    if fragment:
+        match = EGG_FRAGMENT.match(fragment)
+        if match:
+            for dist in interpret_distro_name(
+                url, match.group(1), metadata, precedence=CHECKOUT_DIST
+            ):
+                yield dist
+
+
+def distros_for_location(location, basename, metadata=None):
+    """Yield egg or source distribution objects based on basename"""
+    if basename.endswith('.egg.zip'):
+        basename = basename[:-4]  # strip the .zip
+    if basename.endswith('.egg') and '-' in basename:
+        # only one, unambiguous interpretation
+        return [Distribution.from_location(location, basename, metadata)]
+    if basename.endswith('.whl') and '-' in basename:
+        wheel = Wheel(basename)
+        if not wheel.is_compatible():
+            return []
+        return [Distribution(
+            location=location,
+            project_name=wheel.project_name,
+            version=wheel.version,
+            # Increase priority over eggs.
+            precedence=EGG_DIST + 1,
+        )]
+    if basename.endswith('.exe'):
+        win_base, py_ver, platform = parse_bdist_wininst(basename)
+        if win_base is not None:
+            return interpret_distro_name(
+                location, win_base, metadata, py_ver, BINARY_DIST, platform
+            )
+    # Try source distro extensions (.zip, .tgz, etc.)
+    #
+    for ext in EXTENSIONS:
+        if basename.endswith(ext):
+            basename = basename[:-len(ext)]
+            return interpret_distro_name(location, basename, metadata)
+    return []  # no extension matched
+
+
+def distros_for_filename(filename, metadata=None):
+    """Yield possible egg or source distribution objects based on a filename"""
+    return distros_for_location(
+        normalize_path(filename), os.path.basename(filename), metadata
+    )
+
+
+def interpret_distro_name(
+        location, basename, metadata, py_version=None, precedence=SOURCE_DIST,
+        platform=None
+):
+    """Generate alternative interpretations of a source distro name
+
+    Note: if `location` is a filesystem filename, you should call
+    ``pkg_resources.normalize_path()`` on it before passing it to this
+    routine!
+    """
+    # Generate alternative interpretations of a source distro name
+    # Because some packages are ambiguous as to name/versions split
+    # e.g. "adns-python-1.1.0", "egenix-mx-commercial", etc.
+    # So, we generate each possible interepretation (e.g. "adns, python-1.1.0"
+    # "adns-python, 1.1.0", and "adns-python-1.1.0, no version").  In practice,
+    # the spurious interpretations should be ignored, because in the event
+    # there's also an "adns" package, the spurious "python-1.1.0" version will
+    # compare lower than any numeric version number, and is therefore unlikely
+    # to match a request for it.  It's still a potential problem, though, and
+    # in the long run PyPI and the distutils should go for "safe" names and
+    # versions in distribution archive names (sdist and bdist).
+
+    parts = basename.split('-')
+    if not py_version and any(re.match(r'py\d\.\d$', p) for p in parts[2:]):
+        # it is a bdist_dumb, not an sdist -- bail out
+        return
+
+    for p in range(1, len(parts) + 1):
+        yield Distribution(
+            location, metadata, '-'.join(parts[:p]), '-'.join(parts[p:]),
+            py_version=py_version, precedence=precedence,
+            platform=platform
+        )
+
+
+# From Python 2.7 docs
+def unique_everseen(iterable, key=None):
+    "List unique elements, preserving order. Remember all elements ever seen."
+    # unique_everseen('AAAABBBCCDAABBB') --> A B C D
+    # unique_everseen('ABBCcAD', str.lower) --> A B C D
+    seen = set()
+    seen_add = seen.add
+    if key is None:
+        for element in six.moves.filterfalse(seen.__contains__, iterable):
+            seen_add(element)
+            yield element
+    else:
+        for element in iterable:
+            k = key(element)
+            if k not in seen:
+                seen_add(k)
+                yield element
+
+
+def unique_values(func):
+    """
+    Wrap a function returning an iterable such that the resulting iterable
+    only ever yields unique items.
+    """
+
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        return unique_everseen(func(*args, **kwargs))
+
+    return wrapper
+
+
+REL = re.compile(r"""<([^>]*\srel\s*=\s*['"]?([^'">]+)[^>]*)>""", re.I)
+# this line is here to fix emacs' cruddy broken syntax highlighting
+
+
+@unique_values
+def find_external_links(url, page):
+    """Find rel="homepage" and rel="download" links in `page`, yielding URLs"""
+
+    for match in REL.finditer(page):
+        tag, rel = match.groups()
+        rels = set(map(str.strip, rel.lower().split(',')))
+        if 'homepage' in rels or 'download' in rels:
+            for match in HREF.finditer(tag):
+                yield urllib.parse.urljoin(url, htmldecode(match.group(1)))
+
+    for tag in ("<th>Home Page", "<th>Download URL"):
+        pos = page.find(tag)
+        if pos != -1:
+            match = HREF.search(page, pos)
+            if match:
+                yield urllib.parse.urljoin(url, htmldecode(match.group(1)))
+
+
+class ContentChecker:
+    """
+    A null content checker that defines the interface for checking content
+    """
+
+    def feed(self, block):
+        """
+        Feed a block of data to the hash.
+        """
+        return
+
+    def is_valid(self):
+        """
+        Check the hash. Return False if validation fails.
+        """
+        return True
+
+    def report(self, reporter, template):
+        """
+        Call reporter with information about the checker (hash name)
+        substituted into the template.
+        """
+        return
+
+
+class HashChecker(ContentChecker):
+    pattern = re.compile(
+        r'(?P<hash_name>sha1|sha224|sha384|sha256|sha512|md5)='
+        r'(?P<expected>[a-f0-9]+)'
+    )
+
+    def __init__(self, hash_name, expected):
+        self.hash_name = hash_name
+        self.hash = hashlib.new(hash_name)
+        self.expected = expected
+
+    @classmethod
+    def from_url(cls, url):
+        "Construct a (possibly null) ContentChecker from a URL"
+        fragment = urllib.parse.urlparse(url)[-1]
+        if not fragment:
+            return ContentChecker()
+        match = cls.pattern.search(fragment)
+        if not match:
+            return ContentChecker()
+        return cls(**match.groupdict())
+
+    def feed(self, block):
+        self.hash.update(block)
+
+    def is_valid(self):
+        return self.hash.hexdigest() == self.expected
+
+    def report(self, reporter, template):
+        msg = template % self.hash_name
+        return reporter(msg)
+
+
+class PackageIndex(Environment):
+    """A distribution index that scans web pages for download URLs"""
+
+    def __init__(
+            self, index_url="https://pypi.org/simple/", hosts=('*',),
+            ca_bundle=None, verify_ssl=True, *args, **kw
+    ):
+        Environment.__init__(self, *args, **kw)
+        self.index_url = index_url + "/" [:not index_url.endswith('/')]
+        self.scanned_urls = {}
+        self.fetched_urls = {}
+        self.package_pages = {}
+        self.allows = re.compile('|'.join(map(translate, hosts))).match
+        self.to_scan = []
+        use_ssl = (
+            verify_ssl
+            and ssl_support.is_available
+            and (ca_bundle or ssl_support.find_ca_bundle())
+        )
+        if use_ssl:
+            self.opener = ssl_support.opener_for(ca_bundle)
+        else:
+            self.opener = urllib.request.urlopen
+
+    def process_url(self, url, retrieve=False):
+        """Evaluate a URL as a possible download, and maybe retrieve it"""
+        if url in self.scanned_urls and not retrieve:
+            return
+        self.scanned_urls[url] = True
+        if not URL_SCHEME(url):
+            self.process_filename(url)
+            return
+        else:
+            dists = list(distros_for_url(url))
+            if dists:
+                if not self.url_ok(url):
+                    return
+                self.debug("Found link: %s", url)
+
+        if dists or not retrieve or url in self.fetched_urls:
+            list(map(self.add, dists))
+            return  # don't need the actual page
+
+        if not self.url_ok(url):
+            self.fetched_urls[url] = True
+            return
+
+        self.info("Reading %s", url)
+        self.fetched_urls[url] = True  # prevent multiple fetch attempts
+        tmpl = "Download error on %s: %%s -- Some packages may not be found!"
+        f = self.open_url(url, tmpl % url)
+        if f is None:
+            return
+        if isinstance(f, urllib.error.HTTPError) and f.code == 401:
+            self.info("Authentication error: %s" % f.msg)
+        self.fetched_urls[f.url] = True
+        if 'html' not in f.headers.get('content-type', '').lower():
+            f.close()  # not html, we can't process it
+            return
+
+        base = f.url  # handle redirects
+        page = f.read()
+        if not isinstance(page, str):
+            # In Python 3 and got bytes but want str.
+            if isinstance(f, urllib.error.HTTPError):
+                # Errors have no charset, assume latin1:
+                charset = 'latin-1'
+            else:
+                charset = f.headers.get_param('charset') or 'latin-1'
+            page = page.decode(charset, "ignore")
+        f.close()
+        for match in HREF.finditer(page):
+            link = urllib.parse.urljoin(base, htmldecode(match.group(1)))
+            self.process_url(link)
+        if url.startswith(self.index_url) and getattr(f, 'code', None) != 404:
+            page = self.process_index(url, page)
+
+    def process_filename(self, fn, nested=False):
+        # process filenames or directories
+        if not os.path.exists(fn):
+            self.warn("Not found: %s", fn)
+            return
+
+        if os.path.isdir(fn) and not nested:
+            path = os.path.realpath(fn)
+            for item in os.listdir(path):
+                self.process_filename(os.path.join(path, item), True)
+
+        dists = distros_for_filename(fn)
+        if dists:
+            self.debug("Found: %s", fn)
+            list(map(self.add, dists))
+
+    def url_ok(self, url, fatal=False):
+        s = URL_SCHEME(url)
+        is_file = s and s.group(1).lower() == 'file'
+        if is_file or self.allows(urllib.parse.urlparse(url)[1]):
+            return True
+        msg = (
+            "\nNote: Bypassing %s (disallowed host; see "
+            "http://bit.ly/2hrImnY for details).\n")
+        if fatal:
+            raise DistutilsError(msg % url)
+        else:
+            self.warn(msg, url)
+
+    def scan_egg_links(self, search_path):
+        dirs = filter(os.path.isdir, search_path)
+        egg_links = (
+            (path, entry)
+            for path in dirs
+            for entry in os.listdir(path)
+            if entry.endswith('.egg-link')
+        )
+        list(itertools.starmap(self.scan_egg_link, egg_links))
+
+    def scan_egg_link(self, path, entry):
+        with open(os.path.join(path, entry)) as raw_lines:
+            # filter non-empty lines
+            lines = list(filter(None, map(str.strip, raw_lines)))
+
+        if len(lines) != 2:
+            # format is not recognized; punt
+            return
+
+        egg_path, setup_path = lines
+
+        for dist in find_distributions(os.path.join(path, egg_path)):
+            dist.location = os.path.join(path, *lines)
+            dist.precedence = SOURCE_DIST
+            self.add(dist)
+
+    def process_index(self, url, page):
+        """Process the contents of a PyPI page"""
+
+        def scan(link):
+            # Process a URL to see if it's for a package page
+            if link.startswith(self.index_url):
+                parts = list(map(
+                    urllib.parse.unquote, link[len(self.index_url):].split('/')
+                ))
+                if len(parts) == 2 and '#' not in parts[1]:
+                    # it's a package page, sanitize and index it
+                    pkg = safe_name(parts[0])
+                    ver = safe_version(parts[1])
+                    self.package_pages.setdefault(pkg.lower(), {})[link] = True
+                    return to_filename(pkg), to_filename(ver)
+            return None, None
+
+        # process an index page into the package-page index
+        for match in HREF.finditer(page):
+            try:
+                scan(urllib.parse.urljoin(url, htmldecode(match.group(1))))
+            except ValueError:
+                pass
+
+        pkg, ver = scan(url)  # ensure this page is in the page index
+        if pkg:
+            # process individual package page
+            for new_url in find_external_links(url, page):
+                # Process the found URL
+                base, frag = egg_info_for_url(new_url)
+                if base.endswith('.py') and not frag:
+                    if ver:
+                        new_url += '#egg=%s-%s' % (pkg, ver)
+                    else:
+                        self.need_version_info(url)
+                self.scan_url(new_url)
+
+            return PYPI_MD5.sub(
+                lambda m: '<a href="%s#md5=%s">%s</a>' % m.group(1, 3, 2), page
+            )
+        else:
+            return ""  # no sense double-scanning non-package pages
+
+    def need_version_info(self, url):
+        self.scan_all(
+            "Page at %s links to .py file(s) without version info; an index "
+            "scan is required.", url
+        )
+
+    def scan_all(self, msg=None, *args):
+        if self.index_url not in self.fetched_urls:
+            if msg:
+                self.warn(msg, *args)
+            self.info(
+                "Scanning index of all packages (this may take a while)"
+            )
+        self.scan_url(self.index_url)
+
+    def find_packages(self, requirement):
+        self.scan_url(self.index_url + requirement.unsafe_name + '/')
+
+        if not self.package_pages.get(requirement.key):
+            # Fall back to safe version of the name
+            self.scan_url(self.index_url + requirement.project_name + '/')
+
+        if not self.package_pages.get(requirement.key):
+            # We couldn't find the target package, so search the index page too
+            self.not_found_in_index(requirement)
+
+        for url in list(self.package_pages.get(requirement.key, ())):
+            # scan each page that might be related to the desired package
+            self.scan_url(url)
+
+    def obtain(self, requirement, installer=None):
+        self.prescan()
+        self.find_packages(requirement)
+        for dist in self[requirement.key]:
+            if dist in requirement:
+                return dist
+            self.debug("%s does not match %s", requirement, dist)
+        return super(PackageIndex, self).obtain(requirement, installer)
+
+    def check_hash(self, checker, filename, tfp):
+        """
+        checker is a ContentChecker
+        """
+        checker.report(
+            self.debug,
+            "Validating %%s checksum for %s" % filename)
+        if not checker.is_valid():
+            tfp.close()
+            os.unlink(filename)
+            raise DistutilsError(
+                "%s validation failed for %s; "
+                "possible download problem?"
+                % (checker.hash.name, os.path.basename(filename))
+            )
+
+    def add_find_links(self, urls):
+        """Add `urls` to the list that will be prescanned for searches"""
+        for url in urls:
+            if (
+                self.to_scan is None  # if we have already "gone online"
+                or not URL_SCHEME(url)  # or it's a local file/directory
+                or url.startswith('file:')
+                or list(distros_for_url(url))  # or a direct package link
+            ):
+                # then go ahead and process it now
+                self.scan_url(url)
+            else:
+                # otherwise, defer retrieval till later
+                self.to_scan.append(url)
+
+    def prescan(self):
+        """Scan urls scheduled for prescanning (e.g. --find-links)"""
+        if self.to_scan:
+            list(map(self.scan_url, self.to_scan))
+        self.to_scan = None  # from now on, go ahead and process immediately
+
+    def not_found_in_index(self, requirement):
+        if self[requirement.key]:  # we've seen at least one distro
+            meth, msg = self.info, "Couldn't retrieve index page for %r"
+        else:  # no distros seen for this name, might be misspelled
+            meth, msg = (
+                self.warn,
+                "Couldn't find index page for %r (maybe misspelled?)")
+        meth(msg, requirement.unsafe_name)
+        self.scan_all()
+
+    def download(self, spec, tmpdir):
+        """Locate and/or download `spec` to `tmpdir`, returning a local path
+
+        `spec` may be a ``Requirement`` object, or a string containing a URL,
+        an existing local filename, or a project/version requirement spec
+        (i.e. the string form of a ``Requirement`` object).  If it is the URL
+        of a .py file with an unambiguous ``#egg=name-version`` tag (i.e., one
+        that escapes ``-`` as ``_`` throughout), a trivial ``setup.py`` is
+        automatically created alongside the downloaded file.
+
+        If `spec` is a ``Requirement`` object or a string containing a
+        project/version requirement spec, this method returns the location of
+        a matching distribution (possibly after downloading it to `tmpdir`).
+        If `spec` is a locally existing file or directory name, it is simply
+        returned unchanged.  If `spec` is a URL, it is downloaded to a subpath
+        of `tmpdir`, and the local filename is returned.  Various errors may be
+        raised if a problem occurs during downloading.
+        """
+        if not isinstance(spec, Requirement):
+            scheme = URL_SCHEME(spec)
+            if scheme:
+                # It's a url, download it to tmpdir
+                found = self._download_url(scheme.group(1), spec, tmpdir)
+                base, fragment = egg_info_for_url(spec)
+                if base.endswith('.py'):
+                    found = self.gen_setup(found, fragment, tmpdir)
+                return found
+            elif os.path.exists(spec):
+                # Existing file or directory, just return it
+                return spec
+            else:
+                spec = parse_requirement_arg(spec)
+        return getattr(self.fetch_distribution(spec, tmpdir), 'location', None)
+
+    def fetch_distribution(
+            self, requirement, tmpdir, force_scan=False, source=False,
+            develop_ok=False, local_index=None):
+        """Obtain a distribution suitable for fulfilling `requirement`
+
+        `requirement` must be a ``pkg_resources.Requirement`` instance.
+        If necessary, or if the `force_scan` flag is set, the requirement is
+        searched for in the (online) package index as well as the locally
+        installed packages.  If a distribution matching `requirement` is found,
+        the returned distribution's ``location`` is the value you would have
+        gotten from calling the ``download()`` method with the matching
+        distribution's URL or filename.  If no matching distribution is found,
+        ``None`` is returned.
+
+        If the `source` flag is set, only source distributions and source
+        checkout links will be considered.  Unless the `develop_ok` flag is
+        set, development and system eggs (i.e., those using the ``.egg-info``
+        format) will be ignored.
+        """
+        # process a Requirement
+        self.info("Searching for %s", requirement)
+        skipped = {}
+        dist = None
+
+        def find(req, env=None):
+            if env is None:
+                env = self
+            # Find a matching distribution; may be called more than once
+
+            for dist in env[req.key]:
+
+                if dist.precedence == DEVELOP_DIST and not develop_ok:
+                    if dist not in skipped:
+                        self.warn(
+                            "Skipping development or system egg: %s", dist,
+                        )
+                        skipped[dist] = 1
+                    continue
+
+                test = (
+                    dist in req
+                    and (dist.precedence <= SOURCE_DIST or not source)
+                )
+                if test:
+                    loc = self.download(dist.location, tmpdir)
+                    dist.download_location = loc
+                    if os.path.exists(dist.download_location):
+                        return dist
+
+        if force_scan:
+            self.prescan()
+            self.find_packages(requirement)
+            dist = find(requirement)
+
+        if not dist and local_index is not None:
+            dist = find(requirement, local_index)
+
+        if dist is None:
+            if self.to_scan is not None:
+                self.prescan()
+            dist = find(requirement)
+
+        if dist is None and not force_scan:
+            self.find_packages(requirement)
+            dist = find(requirement)
+
+        if dist is None:
+            self.warn(
+                "No local packages or working download links found for %s%s",
+                (source and "a source distribution of " or ""),
+                requirement,
+            )
+        else:
+            self.info("Best match: %s", dist)
+            return dist.clone(location=dist.download_location)
+
+    def fetch(self, requirement, tmpdir, force_scan=False, source=False):
+        """Obtain a file suitable for fulfilling `requirement`
+
+        DEPRECATED; use the ``fetch_distribution()`` method now instead.  For
+        backward compatibility, this routine is identical but returns the
+        ``location`` of the downloaded distribution instead of a distribution
+        object.
+        """
+        dist = self.fetch_distribution(requirement, tmpdir, force_scan, source)
+        if dist is not None:
+            return dist.location
+        return None
+
+    def gen_setup(self, filename, fragment, tmpdir):
+        match = EGG_FRAGMENT.match(fragment)
+        dists = match and [
+            d for d in
+            interpret_distro_name(filename, match.group(1), None) if d.version
+        ] or []
+
+        if len(dists) == 1:  # unambiguous ``#egg`` fragment
+            basename = os.path.basename(filename)
+
+            # Make sure the file has been downloaded to the temp dir.
+            if os.path.dirname(filename) != tmpdir:
+                dst = os.path.join(tmpdir, basename)
+                from setuptools.command.easy_install import samefile
+                if not samefile(filename, dst):
+                    shutil.copy2(filename, dst)
+                    filename = dst
+
+            with open(os.path.join(tmpdir, 'setup.py'), 'w') as file:
+                file.write(
+                    "from setuptools import setup\n"
+                    "setup(name=%r, version=%r, py_modules=[%r])\n"
+                    % (
+                        dists[0].project_name, dists[0].version,
+                        os.path.splitext(basename)[0]
+                    )
+                )
+            return filename
+
+        elif match:
+            raise DistutilsError(
+                "Can't unambiguously interpret project/version identifier %r; "
+                "any dashes in the name or version should be escaped using "
+                "underscores. %r" % (fragment, dists)
+            )
+        else:
+            raise DistutilsError(
+                "Can't process plain .py files without an '#egg=name-version'"
+                " suffix to enable automatic setup script generation."
+            )
+
+    dl_blocksize = 8192
+
+    def _download_to(self, url, filename):
+        self.info("Downloading %s", url)
+        # Download the file
+        fp = None
+        try:
+            checker = HashChecker.from_url(url)
+            fp = self.open_url(url)
+            if isinstance(fp, urllib.error.HTTPError):
+                raise DistutilsError(
+                    "Can't download %s: %s %s" % (url, fp.code, fp.msg)
+                )
+            headers = fp.info()
+            blocknum = 0
+            bs = self.dl_blocksize
+            size = -1
+            if "content-length" in headers:
+                # Some servers return multiple Content-Length headers :(
+                sizes = get_all_headers(headers, 'Content-Length')
+                size = max(map(int, sizes))
+                self.reporthook(url, filename, blocknum, bs, size)
+            with open(filename, 'wb') as tfp:
+                while True:
+                    block = fp.read(bs)
+                    if block:
+                        checker.feed(block)
+                        tfp.write(block)
+                        blocknum += 1
+                        self.reporthook(url, filename, blocknum, bs, size)
+                    else:
+                        break
+                self.check_hash(checker, filename, tfp)
+            return headers
+        finally:
+            if fp:
+                fp.close()
+
+    def reporthook(self, url, filename, blocknum, blksize, size):
+        pass  # no-op
+
+    def open_url(self, url, warning=None):
+        if url.startswith('file:'):
+            return local_open(url)
+        try:
+            return open_with_auth(url, self.opener)
+        except (ValueError, http_client.InvalidURL) as v:
+            msg = ' '.join([str(arg) for arg in v.args])
+            if warning:
+                self.warn(warning, msg)
+            else:
+                raise DistutilsError('%s %s' % (url, msg))
+        except urllib.error.HTTPError as v:
+            return v
+        except urllib.error.URLError as v:
+            if warning:
+                self.warn(warning, v.reason)
+            else:
+                raise DistutilsError("Download error for %s: %s"
+                                     % (url, v.reason))
+        except http_client.BadStatusLine as v:
+            if warning:
+                self.warn(warning, v.line)
+            else:
+                raise DistutilsError(
+                    '%s returned a bad status line. The server might be '
+                    'down, %s' %
+                    (url, v.line)
+                )
+        except (http_client.HTTPException, socket.error) as v:
+            if warning:
+                self.warn(warning, v)
+            else:
+                raise DistutilsError("Download error for %s: %s"
+                                     % (url, v))
+
+    def _download_url(self, scheme, url, tmpdir):
+        # Determine download filename
+        #
+        name, fragment = egg_info_for_url(url)
+        if name:
+            while '..' in name:
+                name = name.replace('..', '.').replace('\\', '_')
+        else:
+            name = "__downloaded__"  # default if URL has no path contents
+
+        if name.endswith('.egg.zip'):
+            name = name[:-4]  # strip the extra .zip before download
+
+        filename = os.path.join(tmpdir, name)
+
+        # Download the file
+        #
+        if scheme == 'svn' or scheme.startswith('svn+'):
+            return self._download_svn(url, filename)
+        elif scheme == 'git' or scheme.startswith('git+'):
+            return self._download_git(url, filename)
+        elif scheme.startswith('hg+'):
+            return self._download_hg(url, filename)
+        elif scheme == 'file':
+            return urllib.request.url2pathname(urllib.parse.urlparse(url)[2])
+        else:
+            self.url_ok(url, True)  # raises error if not allowed
+            return self._attempt_download(url, filename)
+
+    def scan_url(self, url):
+        self.process_url(url, True)
+
+    def _attempt_download(self, url, filename):
+        headers = self._download_to(url, filename)
+        if 'html' in headers.get('content-type', '').lower():
+            return self._download_html(url, headers, filename)
+        else:
+            return filename
+
+    def _download_html(self, url, headers, filename):
+        file = open(filename)
+        for line in file:
+            if line.strip():
+                # Check for a subversion index page
+                if re.search(r'<title>([^- ]+ - )?Revision \d+:', line):
+                    # it's a subversion index page:
+                    file.close()
+                    os.unlink(filename)
+                    return self._download_svn(url, filename)
+                break  # not an index page
+        file.close()
+        os.unlink(filename)
+        raise DistutilsError("Unexpected HTML page found at " + url)
+
+    def _download_svn(self, url, filename):
+        warnings.warn("SVN download support is deprecated", UserWarning)
+        url = url.split('#', 1)[0]  # remove any fragment for svn's sake
+        creds = ''
+        if url.lower().startswith('svn:') and '@' in url:
+            scheme, netloc, path, p, q, f = urllib.parse.urlparse(url)
+            if not netloc and path.startswith('//') and '/' in path[2:]:
+                netloc, path = path[2:].split('/', 1)
+                auth, host = _splituser(netloc)
+                if auth:
+                    if ':' in auth:
+                        user, pw = auth.split(':', 1)
+                        creds = " --username=%s --password=%s" % (user, pw)
+                    else:
+                        creds = " --username=" + auth
+                    netloc = host
+                    parts = scheme, netloc, url, p, q, f
+                    url = urllib.parse.urlunparse(parts)
+        self.info("Doing subversion checkout from %s to %s", url, filename)
+        os.system("svn checkout%s -q %s %s" % (creds, url, filename))
+        return filename
+
+    @staticmethod
+    def _vcs_split_rev_from_url(url, pop_prefix=False):
+        scheme, netloc, path, query, frag = urllib.parse.urlsplit(url)
+
+        scheme = scheme.split('+', 1)[-1]
+
+        # Some fragment identification fails
+        path = path.split('#', 1)[0]
+
+        rev = None
+        if '@' in path:
+            path, rev = path.rsplit('@', 1)
+
+        # Also, discard fragment
+        url = urllib.parse.urlunsplit((scheme, netloc, path, query, ''))
+
+        return url, rev
+
+    def _download_git(self, url, filename):
+        filename = filename.split('#', 1)[0]
+        url, rev = self._vcs_split_rev_from_url(url, pop_prefix=True)
+
+        self.info("Doing git clone from %s to %s", url, filename)
+        os.system("git clone --quiet %s %s" % (url, filename))
+
+        if rev is not None:
+            self.info("Checking out %s", rev)
+            os.system("git -C %s checkout --quiet %s" % (
+                filename,
+                rev,
+            ))
+
+        return filename
+
+    def _download_hg(self, url, filename):
+        filename = filename.split('#', 1)[0]
+        url, rev = self._vcs_split_rev_from_url(url, pop_prefix=True)
+
+        self.info("Doing hg clone from %s to %s", url, filename)
+        os.system("hg clone --quiet %s %s" % (url, filename))
+
+        if rev is not None:
+            self.info("Updating to %s", rev)
+            os.system("hg --cwd %s up -C -r %s -q" % (
+                filename,
+                rev,
+            ))
+
+        return filename
+
+    def debug(self, msg, *args):
+        log.debug(msg, *args)
+
+    def info(self, msg, *args):
+        log.info(msg, *args)
+
+    def warn(self, msg, *args):
+        log.warn(msg, *args)
+
+
+# This pattern matches a character entity reference (a decimal numeric
+# references, a hexadecimal numeric reference, or a named reference).
+entity_sub = re.compile(r'&(#(\d+|x[\da-fA-F]+)|[\w.:-]+);?').sub
+
+
+def decode_entity(match):
+    what = match.group(0)
+    return unescape(what)
+
+
+def htmldecode(text):
+    """
+    Decode HTML entities in the given text.
+
+    >>> htmldecode(
+    ...     'https://../package_name-0.1.2.tar.gz'
+    ...     '?tokena=A&amp;tokenb=B">package_name-0.1.2.tar.gz')
+    'https://../package_name-0.1.2.tar.gz?tokena=A&tokenb=B">package_name-0.1.2.tar.gz'
+    """
+    return entity_sub(decode_entity, text)
+
+
+def socket_timeout(timeout=15):
+    def _socket_timeout(func):
+        def _socket_timeout(*args, **kwargs):
+            old_timeout = socket.getdefaulttimeout()
+            socket.setdefaulttimeout(timeout)
+            try:
+                return func(*args, **kwargs)
+            finally:
+                socket.setdefaulttimeout(old_timeout)
+
+        return _socket_timeout
+
+    return _socket_timeout
+
+
+def _encode_auth(auth):
+    """
+    A function compatible with Python 2.3-3.3 that will encode
+    auth from a URL suitable for an HTTP header.
+    >>> str(_encode_auth('username%3Apassword'))
+    'dXNlcm5hbWU6cGFzc3dvcmQ='
+
+    Long auth strings should not cause a newline to be inserted.
+    >>> long_auth = 'username:' + 'password'*10
+    >>> chr(10) in str(_encode_auth(long_auth))
+    False
+    """
+    auth_s = urllib.parse.unquote(auth)
+    # convert to bytes
+    auth_bytes = auth_s.encode()
+    encoded_bytes = base64.b64encode(auth_bytes)
+    # convert back to a string
+    encoded = encoded_bytes.decode()
+    # strip the trailing carriage return
+    return encoded.replace('\n', '')
+
+
+class Credential:
+    """
+    A username/password pair. Use like a namedtuple.
+    """
+
+    def __init__(self, username, password):
+        self.username = username
+        self.password = password
+
+    def __iter__(self):
+        yield self.username
+        yield self.password
+
+    def __str__(self):
+        return '%(username)s:%(password)s' % vars(self)
+
+
+class PyPIConfig(configparser.RawConfigParser):
+    def __init__(self):
+        """
+        Load from ~/.pypirc
+        """
+        defaults = dict.fromkeys(['username', 'password', 'repository'], '')
+        configparser.RawConfigParser.__init__(self, defaults)
+
+        rc = os.path.join(os.path.expanduser('~'), '.pypirc')
+        if os.path.exists(rc):
+            self.read(rc)
+
+    @property
+    def creds_by_repository(self):
+        sections_with_repositories = [
+            section for section in self.sections()
+            if self.get(section, 'repository').strip()
+        ]
+
+        return dict(map(self._get_repo_cred, sections_with_repositories))
+
+    def _get_repo_cred(self, section):
+        repo = self.get(section, 'repository').strip()
+        return repo, Credential(
+            self.get(section, 'username').strip(),
+            self.get(section, 'password').strip(),
+        )
+
+    def find_credential(self, url):
+        """
+        If the URL indicated appears to be a repository defined in this
+        config, return the credential for that repository.
+        """
+        for repository, cred in self.creds_by_repository.items():
+            if url.startswith(repository):
+                return cred
+
+
+def open_with_auth(url, opener=urllib.request.urlopen):
+    """Open a urllib2 request, handling HTTP authentication"""
+
+    parsed = urllib.parse.urlparse(url)
+    scheme, netloc, path, params, query, frag = parsed
+
+    # Double scheme does not raise on Mac OS X as revealed by a
+    # failing test. We would expect "nonnumeric port". Refs #20.
+    if netloc.endswith(':'):
+        raise http_client.InvalidURL("nonnumeric port: ''")
+
+    if scheme in ('http', 'https'):
+        auth, address = _splituser(netloc)
+    else:
+        auth = None
+
+    if not auth:
+        cred = PyPIConfig().find_credential(url)
+        if cred:
+            auth = str(cred)
+            info = cred.username, url
+            log.info('Authenticating as %s for %s (from .pypirc)', *info)
+
+    if auth:
+        auth = "Basic " + _encode_auth(auth)
+        parts = scheme, address, path, params, query, frag
+        new_url = urllib.parse.urlunparse(parts)
+        request = urllib.request.Request(new_url)
+        request.add_header("Authorization", auth)
+    else:
+        request = urllib.request.Request(url)
+
+    request.add_header('User-Agent', user_agent)
+    fp = opener(request)
+
+    if auth:
+        # Put authentication info back into request URL if same host,
+        # so that links found on the page will work
+        s2, h2, path2, param2, query2, frag2 = urllib.parse.urlparse(fp.url)
+        if s2 == scheme and h2 == address:
+            parts = s2, netloc, path2, param2, query2, frag2
+            fp.url = urllib.parse.urlunparse(parts)
+
+    return fp
+
+
+# copy of urllib.parse._splituser from Python 3.8
+def _splituser(host):
+    """splituser('user[:passwd]@host[:port]')
+    --> 'user[:passwd]', 'host[:port]'."""
+    user, delim, host = host.rpartition('@')
+    return (user if delim else None), host
+
+
+# adding a timeout to avoid freezing package_index
+open_with_auth = socket_timeout(_SOCKET_TIMEOUT)(open_with_auth)
+
+
+def fix_sf_url(url):
+    return url  # backward compatibility
+
+
+def local_open(url):
+    """Read a local path, with special support for directories"""
+    scheme, server, path, param, query, frag = urllib.parse.urlparse(url)
+    filename = urllib.request.url2pathname(path)
+    if os.path.isfile(filename):
+        return urllib.request.urlopen(url)
+    elif path.endswith('/') and os.path.isdir(filename):
+        files = []
+        for f in os.listdir(filename):
+            filepath = os.path.join(filename, f)
+            if f == 'index.html':
+                with open(filepath, 'r') as fp:
+                    body = fp.read()
+                break
+            elif os.path.isdir(filepath):
+                f += '/'
+            files.append('<a href="{name}">{name}</a>'.format(name=f))
+        else:
+            tmpl = (
+                "<html><head><title>{url}</title>"
+                "</head><body>{files}</body></html>")
+            body = tmpl.format(url=url, files='\n'.join(files))
+        status, message = 200, "OK"
+    else:
+        status, message, body = 404, "Path not found", "Not found"
+
+    headers = {'content-type': 'text/html'}
+    body_stream = six.StringIO(body)
+    return urllib.error.HTTPError(url, status, message, headers, body_stream)