text: import datetime
  import hashlib
  import json
  import logging
  import os.path
  import sys
  
  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.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_distribution, get_installed_version
  from pip._internal.utils.packaging import get_installer
  from pip._internal.utils.typing import MYPY_CHECK_RUNNING
  
  if MYPY_CHECK_RUNNING:
      import optparse
      from typing import Any, Dict
  
      from pip._internal.network.session import PipSession
  
  
  SELFCHECK_DATE_FMT = "%Y-%m-%dT%H:%M:%SZ"
  
  
  logger = logging.getLogger(__name__)
  
  
  def _get_statefile_name(key):
      # type: (str) -> str
      key_bytes = ensure_binary(key)
      name = hashlib.sha224(key_bytes).hexdigest()
      return name
  
  
  class SelfCheckState:
      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 (OSError, ValueError, KeyError):
                  # Explicitly suppressing exceptions, since we don't want to
                  # error out if the cache file is invalid.
                  pass
  
      @property
      def key(self):
          # type: () -> str
          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.
      """
      dist = get_distribution(pkg)
      if not dist:
          return False
      return "pip" == get_installer(dist)
  
  
  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 = LinkCollector.create(
                  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 = f"{sys.executable} -m pip"
          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,
          )
  