text: from __future__ import absolute_import
  
  import logging
  import os.path
  import re
  
  from pip._vendor.packaging.version import parse as parse_version
  from pip._vendor.six.moves.urllib import parse as urllib_parse
  from pip._vendor.six.moves.urllib import request as urllib_request
  
  from pip._internal.exceptions import BadCommand
  from pip._internal.utils.compat import samefile
  from pip._internal.utils.misc import display_path, make_vcs_requirement_url
  from pip._internal.utils.temp_dir import TempDirectory
  from pip._internal.vcs import VersionControl, vcs
  
  urlsplit = urllib_parse.urlsplit
  urlunsplit = urllib_parse.urlunsplit
  
  
  logger = logging.getLogger(__name__)
  
  
  HASH_REGEX = re.compile('[a-fA-F0-9]{40}')
  
  
  def looks_like_hash(sha):
      return bool(HASH_REGEX.match(sha))
  
  
  class Git(VersionControl):
      name = 'git'
      dirname = '.git'
      repo_name = 'clone'
      schemes = (
          'git', 'git+http', 'git+https', 'git+ssh', 'git+git', 'git+file',
      )
      # Prevent the user's environment variables from interfering with pip:
      # https://github.com/pypa/pip/issues/1130
      unset_environ = ('GIT_DIR', 'GIT_WORK_TREE')
      default_arg_rev = 'HEAD'
  
      def __init__(self, url=None, *args, **kwargs):
  
          # Works around an apparent Git bug
          # (see https://article.gmane.org/gmane.comp.version-control.git/146500)
          if url:
              scheme, netloc, path, query, fragment = urlsplit(url)
              if scheme.endswith('file'):
                  initial_slashes = path[:-len(path.lstrip('/'))]
                  newpath = (
                      initial_slashes +
                      urllib_request.url2pathname(path)
                      .replace('\\', '/').lstrip('/')
                  )
                  url = urlunsplit((scheme, netloc, newpath, query, fragment))
                  after_plus = scheme.find('+') + 1
                  url = scheme[:after_plus] + urlunsplit(
                      (scheme[after_plus:], netloc, newpath, query, fragment),
                  )
  
          super(Git, self).__init__(url, *args, **kwargs)
  
      def get_base_rev_args(self, rev):
          return [rev]
  
      def get_git_version(self):
          VERSION_PFX = 'git version '
          version = self.run_command(['version'], show_stdout=False)
          if version.startswith(VERSION_PFX):
              version = version[len(VERSION_PFX):].split()[0]
          else:
              version = ''
          # get first 3 positions of the git version becasue
          # on windows it is x.y.z.windows.t, and this parses as
          # LegacyVersion which always smaller than a Version.
          version = '.'.join(version.split('.')[:3])
          return parse_version(version)
  
      def get_branch(self, location):
          """
          Return the current branch, or None if HEAD isn't at a branch
          (e.g. detached HEAD).
          """
          args = ['rev-parse', '--abbrev-ref', 'HEAD']
          output = self.run_command(args, show_stdout=False, cwd=location)
          branch = output.strip()
  
          if branch == 'HEAD':
              return None
  
          return branch
  
      def export(self, location):
          """Export the Git repository at the url to the destination location"""
          if not location.endswith('/'):
              location = location + '/'
  
          with TempDirectory(kind="export") as temp_dir:
              self.unpack(temp_dir.path)
              self.run_command(
                  ['checkout-index', '-a', '-f', '--prefix', location],
                  show_stdout=False, cwd=temp_dir.path
              )
  
      def get_revision_sha(self, dest, rev):
          """
          Return (sha_or_none, is_branch), where sha_or_none is a commit hash
          if the revision names a remote branch or tag, otherwise None.
  
          Args:
            dest: the repository directory.
            rev: the revision name.
          """
          # Pass rev to pre-filter the list.
          output = self.run_command(['show-ref', rev], cwd=dest,
                                    show_stdout=False, on_returncode='ignore')
          refs = {}
          for line in output.strip().splitlines():
              try:
                  sha, ref = line.split()
              except ValueError:
                  # Include the offending line to simplify troubleshooting if
                  # this error ever occurs.
                  raise ValueError('unexpected show-ref line: {!r}'.format(line))
  
              refs[ref] = sha
  
          branch_ref = 'refs/remotes/origin/{}'.format(rev)
          tag_ref = 'refs/tags/{}'.format(rev)
  
          sha = refs.get(branch_ref)
          if sha is not None:
              return (sha, True)
  
          sha = refs.get(tag_ref)
  
          return (sha, False)
  
      def resolve_revision(self, dest, url, rev_options):
          """
          Resolve a revision to a new RevOptions object with the SHA1 of the
          branch, tag, or ref if found.
  
          Args:
            rev_options: a RevOptions object.
          """
          rev = rev_options.arg_rev
          sha, is_branch = self.get_revision_sha(dest, rev)
  
          if sha is not None:
              rev_options = rev_options.make_new(sha)
              rev_options.branch_name = rev if is_branch else None
  
              return rev_options
  
          # Do not show a warning for the common case of something that has
          # the form of a Git commit hash.
          if not looks_like_hash(rev):
              logger.warning(
                  "Did not find branch or tag '%s', assuming revision or ref.",
                  rev,
              )
  
          if not rev.startswith('refs/'):
              return rev_options
  
          # If it looks like a ref, we have to fetch it explicitly.
          self.run_command(
              ['fetch', '-q', url] + rev_options.to_args(),
              cwd=dest,
          )
          # Change the revision to the SHA of the ref we fetched
          sha = self.get_revision(dest, rev='FETCH_HEAD')
          rev_options = rev_options.make_new(sha)
  
          return rev_options
  
      def is_commit_id_equal(self, dest, name):
          """
          Return whether the current commit hash equals the given name.
  
          Args:
            dest: the repository directory.
            name: a string name.
          """
          if not name:
              # Then avoid an unnecessary subprocess call.
              return False
  
          return self.get_revision(dest) == name
  
      def fetch_new(self, dest, url, rev_options):
          rev_display = rev_options.to_display()
          logger.info(
              'Cloning %s%s to %s', url, rev_display, display_path(dest),
          )
          self.run_command(['clone', '-q', url, dest])
  
          if rev_options.rev:
              # Then a specific revision was requested.
              rev_options = self.resolve_revision(dest, url, rev_options)
              branch_name = getattr(rev_options, 'branch_name', None)
              if branch_name is None:
                  # Only do a checkout if the current commit id doesn't match
                  # the requested revision.
                  if not self.is_commit_id_equal(dest, rev_options.rev):
                      cmd_args = ['checkout', '-q'] + rev_options.to_args()
                      self.run_command(cmd_args, cwd=dest)
              elif self.get_branch(dest) != branch_name:
                  # Then a specific branch was requested, and that branch
                  # is not yet checked out.
                  track_branch = 'origin/{}'.format(branch_name)
                  cmd_args = [
                      'checkout', '-b', branch_name, '--track', track_branch,
                  ]
                  self.run_command(cmd_args, cwd=dest)
  
          #: repo may contain submodules
          self.update_submodules(dest)
  
      def switch(self, dest, url, rev_options):
          self.run_command(['config', 'remote.origin.url', url], cwd=dest)
          cmd_args = ['checkout', '-q'] + rev_options.to_args()
          self.run_command(cmd_args, cwd=dest)
  
          self.update_submodules(dest)
  
      def update(self, dest, url, rev_options):
          # First fetch changes from the default remote
          if self.get_git_version() >= parse_version('1.9.0'):
              # fetch tags in addition to everything else
              self.run_command(['fetch', '-q', '--tags'], cwd=dest)
          else:
              self.run_command(['fetch', '-q'], cwd=dest)
          # Then reset to wanted revision (maybe even origin/main)
          rev_options = self.resolve_revision(dest, url, rev_options)
          cmd_args = ['reset', '--hard', '-q'] + rev_options.to_args()
          self.run_command(cmd_args, cwd=dest)
          #: update submodules
          self.update_submodules(dest)
  
      def get_url(self, location):
          """Return URL of the first remote encountered."""
          remotes = self.run_command(
              ['config', '--get-regexp', r'remote\..*\.url'],
              show_stdout=False, cwd=location,
          )
          remotes = remotes.splitlines()
          found_remote = remotes[0]
          for remote in remotes:
              if remote.startswith('remote.origin.url '):
                  found_remote = remote
                  break
          url = found_remote.split(' ')[1]
          return url.strip()
  
      def get_revision(self, location, rev=None):
          if rev is None:
              rev = 'HEAD'
          current_rev = self.run_command(
              ['rev-parse', rev], show_stdout=False, cwd=location,
          )
          return current_rev.strip()
  
      def _get_subdirectory(self, location):
          """Return the relative path of setup.py to the git repo root."""
          # find the repo root
          git_dir = self.run_command(['rev-parse', '--git-dir'],
                                     show_stdout=False, cwd=location).strip()
          if not os.path.isabs(git_dir):
              git_dir = os.path.join(location, git_dir)
          root_dir = os.path.join(git_dir, '..')
          # find setup.py
          orig_location = location
          while not os.path.exists(os.path.join(location, 'setup.py')):
              last_location = location
              location = os.path.dirname(location)
              if location == last_location:
                  # We've traversed up to the root of the filesystem without
                  # finding setup.py
                  logger.warning(
                      "Could not find setup.py for directory %s (tried all "
                      "parent directories)",
                      orig_location,
                  )
                  return None
          # relative path of setup.py to repo root
          if samefile(root_dir, location):
              return None
          return os.path.relpath(location, root_dir)
  
      def get_src_requirement(self, dist, location):
          repo = self.get_url(location)
          if not repo.lower().startswith('git:'):
              repo = 'git+' + repo
          current_rev = self.get_revision(location)
          egg_project_name = dist.egg_name().split('-', 1)[0]
          subdir = self._get_subdirectory(location)
          req = make_vcs_requirement_url(repo, current_rev, egg_project_name,
                                         subdir=subdir)
  
          return req
  
      def get_url_rev_and_auth(self, url):
          """
          Prefixes stub URLs like 'user@hostname:user/repo.git' with 'ssh://'.
          That's required because although they use SSH they sometimes don't
          work with a ssh:// scheme (e.g. GitHub). But we need a scheme for
          parsing. Hence we remove it again afterwards and return it as a stub.
          """
          if '://' not in url:
              assert 'file:' not in url
              url = url.replace('git+', 'git+ssh://')
              url, rev, user_pass = super(Git, self).get_url_rev_and_auth(url)
              url = url.replace('ssh://', '')
          else:
              url, rev, user_pass = super(Git, self).get_url_rev_and_auth(url)
  
          return url, rev, user_pass
  
      def update_submodules(self, location):
          if not os.path.exists(os.path.join(location, '.gitmodules')):
              return
          self.run_command(
              ['submodule', 'update', '--init', '--recursive', '-q'],
              cwd=location,
          )
  
      @classmethod
      def controls_location(cls, location):
          if super(Git, cls).controls_location(location):
              return True
          try:
              r = cls().run_command(['rev-parse'],
                                    cwd=location,
                                    show_stdout=False,
                                    on_returncode='ignore')
              return not r
          except BadCommand:
              logger.debug("could not determine if %s is under git control "
                           "because git is not available", location)
              return False
  
  
  vcs.register(Git)
  