--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_internal/network/session.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,405 @@
+"""PipSession and supporting code, containing all pip-specific
+network request configuration and behavior.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import email.utils
+import json
+import logging
+import mimetypes
+import os
+import platform
+import sys
+import warnings
+
+from pip._vendor import requests, six, urllib3
+from pip._vendor.cachecontrol import CacheControlAdapter
+from pip._vendor.requests.adapters import BaseAdapter, HTTPAdapter
+from pip._vendor.requests.models import Response
+from pip._vendor.requests.structures import CaseInsensitiveDict
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.urllib3.exceptions import InsecureRequestWarning
+
+from pip import __version__
+from pip._internal.network.auth import MultiDomainBasicAuth
+from pip._internal.network.cache import SafeFileCache
+# Import ssl from compat so the initial import occurs in only one place.
+from pip._internal.utils.compat import has_tls, ipaddress
+from pip._internal.utils.glibc import libc_ver
+from pip._internal.utils.misc import (
+    build_url_from_netloc,
+    get_installed_version,
+    parse_netloc,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import url_to_path
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Iterator, List, Optional, Tuple, Union,
+    )
+
+    from pip._internal.models.link import Link
+
+    SecureOrigin = Tuple[str, str, Optional[Union[int, str]]]
+
+
+logger = logging.getLogger(__name__)
+
+
+# Ignore warning raised when using --trusted-host.
+warnings.filterwarnings("ignore", category=InsecureRequestWarning)
+
+
+SECURE_ORIGINS = [
+    # protocol, hostname, port
+    # Taken from Chrome's list of secure origins (See: http://bit.ly/1qrySKC)
+    ("https", "*", "*"),
+    ("*", "localhost", "*"),
+    ("*", "127.0.0.0/8", "*"),
+    ("*", "::1/128", "*"),
+    ("file", "*", None),
+    # ssh is always secure.
+    ("ssh", "*", "*"),
+]  # type: List[SecureOrigin]
+
+
+# These are environment variables present when running under various
+# CI systems.  For each variable, some CI systems that use the variable
+# are indicated.  The collection was chosen so that for each of a number
+# of popular systems, at least one of the environment variables is used.
+# This list is used to provide some indication of and lower bound for
+# CI traffic to PyPI.  Thus, it is okay if the list is not comprehensive.
+# For more background, see: https://github.com/pypa/pip/issues/5499
+CI_ENVIRONMENT_VARIABLES = (
+    # Azure Pipelines
+    'BUILD_BUILDID',
+    # Jenkins
+    'BUILD_ID',
+    # AppVeyor, CircleCI, Codeship, Gitlab CI, Shippable, Travis CI
+    'CI',
+    # Explicit environment variable.
+    'PIP_IS_CI',
+)
+
+
+def looks_like_ci():
+    # type: () -> bool
+    """
+    Return whether it looks like pip is running under CI.
+    """
+    # We don't use the method of checking for a tty (e.g. using isatty())
+    # because some CI systems mimic a tty (e.g. Travis CI).  Thus that
+    # method doesn't provide definitive information in either direction.
+    return any(name in os.environ for name in CI_ENVIRONMENT_VARIABLES)
+
+
+def user_agent():
+    """
+    Return a string representing the user agent.
+    """
+    data = {
+        "installer": {"name": "pip", "version": __version__},
+        "python": platform.python_version(),
+        "implementation": {
+            "name": platform.python_implementation(),
+        },
+    }
+
+    if data["implementation"]["name"] == 'CPython':
+        data["implementation"]["version"] = platform.python_version()
+    elif data["implementation"]["name"] == 'PyPy':
+        if sys.pypy_version_info.releaselevel == 'final':
+            pypy_version_info = sys.pypy_version_info[:3]
+        else:
+            pypy_version_info = sys.pypy_version_info
+        data["implementation"]["version"] = ".".join(
+            [str(x) for x in pypy_version_info]
+        )
+    elif data["implementation"]["name"] == 'Jython':
+        # Complete Guess
+        data["implementation"]["version"] = platform.python_version()
+    elif data["implementation"]["name"] == 'IronPython':
+        # Complete Guess
+        data["implementation"]["version"] = platform.python_version()
+
+    if sys.platform.startswith("linux"):
+        from pip._vendor import distro
+        distro_infos = dict(filter(
+            lambda x: x[1],
+            zip(["name", "version", "id"], distro.linux_distribution()),
+        ))
+        libc = dict(filter(
+            lambda x: x[1],
+            zip(["lib", "version"], libc_ver()),
+        ))
+        if libc:
+            distro_infos["libc"] = libc
+        if distro_infos:
+            data["distro"] = distro_infos
+
+    if sys.platform.startswith("darwin") and platform.mac_ver()[0]:
+        data["distro"] = {"name": "macOS", "version": platform.mac_ver()[0]}
+
+    if platform.system():
+        data.setdefault("system", {})["name"] = platform.system()
+
+    if platform.release():
+        data.setdefault("system", {})["release"] = platform.release()
+
+    if platform.machine():
+        data["cpu"] = platform.machine()
+
+    if has_tls():
+        import _ssl as ssl
+        data["openssl_version"] = ssl.OPENSSL_VERSION
+
+    setuptools_version = get_installed_version("setuptools")
+    if setuptools_version is not None:
+        data["setuptools_version"] = setuptools_version
+
+    # Use None rather than False so as not to give the impression that
+    # pip knows it is not being run under CI.  Rather, it is a null or
+    # inconclusive result.  Also, we include some value rather than no
+    # value to make it easier to know that the check has been run.
+    data["ci"] = True if looks_like_ci() else None
+
+    user_data = os.environ.get("PIP_USER_AGENT_USER_DATA")
+    if user_data is not None:
+        data["user_data"] = user_data
+
+    return "{data[installer][name]}/{data[installer][version]} {json}".format(
+        data=data,
+        json=json.dumps(data, separators=(",", ":"), sort_keys=True),
+    )
+
+
+class LocalFSAdapter(BaseAdapter):
+
+    def send(self, request, stream=None, timeout=None, verify=None, cert=None,
+             proxies=None):
+        pathname = url_to_path(request.url)
+
+        resp = Response()
+        resp.status_code = 200
+        resp.url = request.url
+
+        try:
+            stats = os.stat(pathname)
+        except OSError as exc:
+            resp.status_code = 404
+            resp.raw = exc
+        else:
+            modified = email.utils.formatdate(stats.st_mtime, usegmt=True)
+            content_type = mimetypes.guess_type(pathname)[0] or "text/plain"
+            resp.headers = CaseInsensitiveDict({
+                "Content-Type": content_type,
+                "Content-Length": stats.st_size,
+                "Last-Modified": modified,
+            })
+
+            resp.raw = open(pathname, "rb")
+            resp.close = resp.raw.close
+
+        return resp
+
+    def close(self):
+        pass
+
+
+class InsecureHTTPAdapter(HTTPAdapter):
+
+    def cert_verify(self, conn, url, verify, cert):
+        super(InsecureHTTPAdapter, self).cert_verify(
+            conn=conn, url=url, verify=False, cert=cert
+        )
+
+
+class PipSession(requests.Session):
+
+    timeout = None  # type: Optional[int]
+
+    def __init__(self, *args, **kwargs):
+        """
+        :param trusted_hosts: Domains not to emit warnings for when not using
+            HTTPS.
+        """
+        retries = kwargs.pop("retries", 0)
+        cache = kwargs.pop("cache", None)
+        trusted_hosts = kwargs.pop("trusted_hosts", [])  # type: List[str]
+        index_urls = kwargs.pop("index_urls", None)
+
+        super(PipSession, self).__init__(*args, **kwargs)
+
+        # Namespace the attribute with "pip_" just in case to prevent
+        # possible conflicts with the base class.
+        self.pip_trusted_origins = []  # type: List[Tuple[str, Optional[int]]]
+
+        # Attach our User Agent to the request
+        self.headers["User-Agent"] = user_agent()
+
+        # Attach our Authentication handler to the session
+        self.auth = MultiDomainBasicAuth(index_urls=index_urls)
+
+        # Create our urllib3.Retry instance which will allow us to customize
+        # how we handle retries.
+        retries = urllib3.Retry(
+            # Set the total number of retries that a particular request can
+            # have.
+            total=retries,
+
+            # A 503 error from PyPI typically means that the Fastly -> Origin
+            # connection got interrupted in some way. A 503 error in general
+            # is typically considered a transient error so we'll go ahead and
+            # retry it.
+            # A 500 may indicate transient error in Amazon S3
+            # A 520 or 527 - may indicate transient error in CloudFlare
+            status_forcelist=[500, 503, 520, 527],
+
+            # Add a small amount of back off between failed requests in
+            # order to prevent hammering the service.
+            backoff_factor=0.25,
+        )
+
+        # We want to _only_ cache responses on securely fetched origins. We do
+        # this because we can't validate the response of an insecurely fetched
+        # origin, and we don't want someone to be able to poison the cache and
+        # require manual eviction from the cache to fix it.
+        if cache:
+            secure_adapter = CacheControlAdapter(
+                cache=SafeFileCache(cache),
+                max_retries=retries,
+            )
+        else:
+            secure_adapter = HTTPAdapter(max_retries=retries)
+
+        # Our Insecure HTTPAdapter disables HTTPS validation. It does not
+        # support caching (see above) so we'll use it for all http:// URLs as
+        # well as any https:// host that we've marked as ignoring TLS errors
+        # for.
+        insecure_adapter = InsecureHTTPAdapter(max_retries=retries)
+        # Save this for later use in add_insecure_host().
+        self._insecure_adapter = insecure_adapter
+
+        self.mount("https://", secure_adapter)
+        self.mount("http://", insecure_adapter)
+
+        # Enable file:// urls
+        self.mount("file://", LocalFSAdapter())
+
+        for host in trusted_hosts:
+            self.add_trusted_host(host, suppress_logging=True)
+
+    def add_trusted_host(self, host, source=None, suppress_logging=False):
+        # type: (str, Optional[str], bool) -> None
+        """
+        :param host: It is okay to provide a host that has previously been
+            added.
+        :param source: An optional source string, for logging where the host
+            string came from.
+        """
+        if not suppress_logging:
+            msg = 'adding trusted host: {!r}'.format(host)
+            if source is not None:
+                msg += ' (from {})'.format(source)
+            logger.info(msg)
+
+        host_port = parse_netloc(host)
+        if host_port not in self.pip_trusted_origins:
+            self.pip_trusted_origins.append(host_port)
+
+        self.mount(build_url_from_netloc(host) + '/', self._insecure_adapter)
+        if not host_port[1]:
+            # Mount wildcard ports for the same host.
+            self.mount(
+                build_url_from_netloc(host) + ':',
+                self._insecure_adapter
+            )
+
+    def iter_secure_origins(self):
+        # type: () -> Iterator[SecureOrigin]
+        for secure_origin in SECURE_ORIGINS:
+            yield secure_origin
+        for host, port in self.pip_trusted_origins:
+            yield ('*', host, '*' if port is None else port)
+
+    def is_secure_origin(self, location):
+        # type: (Link) -> bool
+        # Determine if this url used a secure transport mechanism
+        parsed = urllib_parse.urlparse(str(location))
+        origin_protocol, origin_host, origin_port = (
+            parsed.scheme, parsed.hostname, parsed.port,
+        )
+
+        # The protocol to use to see if the protocol matches.
+        # Don't count the repository type as part of the protocol: in
+        # cases such as "git+ssh", only use "ssh". (I.e., Only verify against
+        # the last scheme.)
+        origin_protocol = origin_protocol.rsplit('+', 1)[-1]
+
+        # Determine if our origin is a secure origin by looking through our
+        # hardcoded list of secure origins, as well as any additional ones
+        # configured on this PackageFinder instance.
+        for secure_origin in self.iter_secure_origins():
+            secure_protocol, secure_host, secure_port = secure_origin
+            if origin_protocol != secure_protocol and secure_protocol != "*":
+                continue
+
+            try:
+                addr = ipaddress.ip_address(
+                    None
+                    if origin_host is None
+                    else six.ensure_text(origin_host)
+                )
+                network = ipaddress.ip_network(
+                    six.ensure_text(secure_host)
+                )
+            except ValueError:
+                # We don't have both a valid address or a valid network, so
+                # we'll check this origin against hostnames.
+                if (
+                    origin_host and
+                    origin_host.lower() != secure_host.lower() and
+                    secure_host != "*"
+                ):
+                    continue
+            else:
+                # We have a valid address and network, so see if the address
+                # is contained within the network.
+                if addr not in network:
+                    continue
+
+            # Check to see if the port matches.
+            if (
+                origin_port != secure_port and
+                secure_port != "*" and
+                secure_port is not None
+            ):
+                continue
+
+            # If we've gotten here, then this origin matches the current
+            # secure origin and we should return True
+            return True
+
+        # If we've gotten to this point, then the origin isn't secure and we
+        # will not accept it as a valid location to search. We will however
+        # log a warning that we are ignoring it.
+        logger.warning(
+            "The repository located at %s is not a trusted or secure host and "
+            "is being ignored. If this repository is available via HTTPS we "
+            "recommend you use HTTPS instead, otherwise you may silence "
+            "this warning and allow it anyway with '--trusted-host %s'.",
+            origin_host,
+            origin_host,
+        )
+
+        return False
+
+    def request(self, method, url, *args, **kwargs):
+        # Allow setting a default timeout on a session
+        kwargs.setdefault("timeout", self.timeout)
+
+        # Dispatch the actual request
+        return super(PipSession, self).request(method, url, *args, **kwargs)