--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_internal/self_outdated_check.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,242 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import datetime
+import hashlib
+import json
+import logging
+import os.path
+import sys
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging import version as packaging_version
+from pip._vendor.six import ensure_binary
+
+from pip._internal.index.collector import LinkCollector
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.models.search_scope import SearchScope
+from pip._internal.models.selection_prefs import SelectionPreferences
+from pip._internal.utils.filesystem import (
+    adjacent_tmp_file,
+    check_path_owner,
+    replace,
+)
+from pip._internal.utils.misc import (
+    ensure_dir,
+    get_installed_version,
+    redact_auth_from_url,
+)
+from pip._internal.utils.packaging import get_installer
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    import optparse
+    from optparse import Values
+    from typing import Any, Dict, Text, Union
+
+    from pip._internal.network.session import PipSession
+
+
+SELFCHECK_DATE_FMT = "%Y-%m-%dT%H:%M:%SZ"
+
+
+logger = logging.getLogger(__name__)
+
+
+def make_link_collector(
+    session,  # type: PipSession
+    options,  # type: Values
+    suppress_no_index=False,  # type: bool
+):
+    # type: (...) -> LinkCollector
+    """
+    :param session: The Session to use to make requests.
+    :param suppress_no_index: Whether to ignore the --no-index option
+        when constructing the SearchScope object.
+    """
+    index_urls = [options.index_url] + options.extra_index_urls
+    if options.no_index and not suppress_no_index:
+        logger.debug(
+            'Ignoring indexes: %s',
+            ','.join(redact_auth_from_url(url) for url in index_urls),
+        )
+        index_urls = []
+
+    # Make sure find_links is a list before passing to create().
+    find_links = options.find_links or []
+
+    search_scope = SearchScope.create(
+        find_links=find_links, index_urls=index_urls,
+    )
+
+    link_collector = LinkCollector(session=session, search_scope=search_scope)
+
+    return link_collector
+
+
+def _get_statefile_name(key):
+    # type: (Union[str, Text]) -> str
+    key_bytes = ensure_binary(key)
+    name = hashlib.sha224(key_bytes).hexdigest()
+    return name
+
+
+class SelfCheckState(object):
+    def __init__(self, cache_dir):
+        # type: (str) -> None
+        self.state = {}  # type: Dict[str, Any]
+        self.statefile_path = None
+
+        # Try to load the existing state
+        if cache_dir:
+            self.statefile_path = os.path.join(
+                cache_dir, "selfcheck", _get_statefile_name(self.key)
+            )
+            try:
+                with open(self.statefile_path) as statefile:
+                    self.state = json.load(statefile)
+            except (IOError, ValueError, KeyError):
+                # Explicitly suppressing exceptions, since we don't want to
+                # error out if the cache file is invalid.
+                pass
+
+    @property
+    def key(self):
+        return sys.prefix
+
+    def save(self, pypi_version, current_time):
+        # type: (str, datetime.datetime) -> None
+        # If we do not have a path to cache in, don't bother saving.
+        if not self.statefile_path:
+            return
+
+        # Check to make sure that we own the directory
+        if not check_path_owner(os.path.dirname(self.statefile_path)):
+            return
+
+        # Now that we've ensured the directory is owned by this user, we'll go
+        # ahead and make sure that all our directories are created.
+        ensure_dir(os.path.dirname(self.statefile_path))
+
+        state = {
+            # Include the key so it's easy to tell which pip wrote the
+            # file.
+            "key": self.key,
+            "last_check": current_time.strftime(SELFCHECK_DATE_FMT),
+            "pypi_version": pypi_version,
+        }
+
+        text = json.dumps(state, sort_keys=True, separators=(",", ":"))
+
+        with adjacent_tmp_file(self.statefile_path) as f:
+            f.write(ensure_binary(text))
+
+        try:
+            # Since we have a prefix-specific state file, we can just
+            # overwrite whatever is there, no need to check.
+            replace(f.name, self.statefile_path)
+        except OSError:
+            # Best effort.
+            pass
+
+
+def was_installed_by_pip(pkg):
+    # type: (str) -> bool
+    """Checks whether pkg was installed by pip
+
+    This is used not to display the upgrade message when pip is in fact
+    installed by system package manager, such as dnf on Fedora.
+    """
+    try:
+        dist = pkg_resources.get_distribution(pkg)
+        return "pip" == get_installer(dist)
+    except pkg_resources.DistributionNotFound:
+        return False
+
+
+def pip_self_version_check(session, options):
+    # type: (PipSession, optparse.Values) -> None
+    """Check for an update for pip.
+
+    Limit the frequency of checks to once per week. State is stored either in
+    the active virtualenv or in the user's USER_CACHE_DIR keyed off the prefix
+    of the pip script path.
+    """
+    installed_version = get_installed_version("pip")
+    if not installed_version:
+        return
+
+    pip_version = packaging_version.parse(installed_version)
+    pypi_version = None
+
+    try:
+        state = SelfCheckState(cache_dir=options.cache_dir)
+
+        current_time = datetime.datetime.utcnow()
+        # Determine if we need to refresh the state
+        if "last_check" in state.state and "pypi_version" in state.state:
+            last_check = datetime.datetime.strptime(
+                state.state["last_check"],
+                SELFCHECK_DATE_FMT
+            )
+            if (current_time - last_check).total_seconds() < 7 * 24 * 60 * 60:
+                pypi_version = state.state["pypi_version"]
+
+        # Refresh the version if we need to or just see if we need to warn
+        if pypi_version is None:
+            # Lets use PackageFinder to see what the latest pip version is
+            link_collector = make_link_collector(
+                session,
+                options=options,
+                suppress_no_index=True,
+            )
+
+            # Pass allow_yanked=False so we don't suggest upgrading to a
+            # yanked version.
+            selection_prefs = SelectionPreferences(
+                allow_yanked=False,
+                allow_all_prereleases=False,  # Explicitly set to False
+            )
+
+            finder = PackageFinder.create(
+                link_collector=link_collector,
+                selection_prefs=selection_prefs,
+            )
+            best_candidate = finder.find_best_candidate("pip").best_candidate
+            if best_candidate is None:
+                return
+            pypi_version = str(best_candidate.version)
+
+            # save that we've performed a check
+            state.save(pypi_version, current_time)
+
+        remote_version = packaging_version.parse(pypi_version)
+
+        local_version_is_older = (
+            pip_version < remote_version and
+            pip_version.base_version != remote_version.base_version and
+            was_installed_by_pip('pip')
+        )
+
+        # Determine if our pypi_version is older
+        if not local_version_is_older:
+            return
+
+        # We cannot tell how the current pip is available in the current
+        # command context, so be pragmatic here and suggest the command
+        # that's always available. This does not accommodate spaces in
+        # `sys.executable`.
+        pip_cmd = "{} -m pip".format(sys.executable)
+        logger.warning(
+            "You are using pip version %s; however, version %s is "
+            "available.\nYou should consider upgrading via the "
+            "'%s install --upgrade pip' command.",
+            pip_version, pypi_version, pip_cmd
+        )
+    except Exception:
+        logger.debug(
+            "There was an error checking the latest version of pip",
+            exc_info=True,
+        )