--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_internal/operations/prepare.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,591 @@
+"""Prepares a distribution for installation
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import logging
+import mimetypes
+import os
+import shutil
+import sys
+
+from pip._vendor import requests
+from pip._vendor.six import PY2
+
+from pip._internal.distributions import (
+    make_distribution_for_install_requirement,
+)
+from pip._internal.distributions.installed import InstalledDistribution
+from pip._internal.exceptions import (
+    DirectoryUrlHashUnsupported,
+    HashMismatch,
+    HashUnpinned,
+    InstallationError,
+    PreviousBuildDirError,
+    VcsHashUnsupported,
+)
+from pip._internal.utils.filesystem import copy2_fixed
+from pip._internal.utils.hashes import MissingHashes
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.marker_files import write_delete_marker_file
+from pip._internal.utils.misc import (
+    ask_path_exists,
+    backup_dir,
+    display_path,
+    hide_url,
+    path_to_display,
+    rmtree,
+)
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.unpacking import unpack_file
+from pip._internal.vcs import vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Callable, List, Optional, Tuple,
+    )
+
+    from mypy_extensions import TypedDict
+
+    from pip._internal.distributions import AbstractDistribution
+    from pip._internal.index.package_finder import PackageFinder
+    from pip._internal.models.link import Link
+    from pip._internal.network.download import Downloader
+    from pip._internal.req.req_install import InstallRequirement
+    from pip._internal.req.req_tracker import RequirementTracker
+    from pip._internal.utils.hashes import Hashes
+
+    if PY2:
+        CopytreeKwargs = TypedDict(
+            'CopytreeKwargs',
+            {
+                'ignore': Callable[[str, List[str]], List[str]],
+                'symlinks': bool,
+            },
+            total=False,
+        )
+    else:
+        CopytreeKwargs = TypedDict(
+            'CopytreeKwargs',
+            {
+                'copy_function': Callable[[str, str], None],
+                'ignore': Callable[[str, List[str]], List[str]],
+                'ignore_dangling_symlinks': bool,
+                'symlinks': bool,
+            },
+            total=False,
+        )
+
+logger = logging.getLogger(__name__)
+
+
+def _get_prepared_distribution(
+        req,  # type: InstallRequirement
+        req_tracker,  # type: RequirementTracker
+        finder,  # type: PackageFinder
+        build_isolation  # type: bool
+):
+    # type: (...) -> AbstractDistribution
+    """Prepare a distribution for installation.
+    """
+    abstract_dist = make_distribution_for_install_requirement(req)
+    with req_tracker.track(req):
+        abstract_dist.prepare_distribution_metadata(finder, build_isolation)
+    return abstract_dist
+
+
+def unpack_vcs_link(link, location):
+    # type: (Link, str) -> None
+    vcs_backend = vcs.get_backend_for_scheme(link.scheme)
+    assert vcs_backend is not None
+    vcs_backend.unpack(location, url=hide_url(link.url))
+
+
+def _copy_file(filename, location, link):
+    # type: (str, str, Link) -> None
+    copy = True
+    download_location = os.path.join(location, link.filename)
+    if os.path.exists(download_location):
+        response = ask_path_exists(
+            'The file {} exists. (i)gnore, (w)ipe, (b)ackup, (a)abort'.format(
+                display_path(download_location)
+            ),
+            ('i', 'w', 'b', 'a'),
+        )
+        if response == 'i':
+            copy = False
+        elif response == 'w':
+            logger.warning('Deleting %s', display_path(download_location))
+            os.remove(download_location)
+        elif response == 'b':
+            dest_file = backup_dir(download_location)
+            logger.warning(
+                'Backing up %s to %s',
+                display_path(download_location),
+                display_path(dest_file),
+            )
+            shutil.move(download_location, dest_file)
+        elif response == 'a':
+            sys.exit(-1)
+    if copy:
+        shutil.copy(filename, download_location)
+        logger.info('Saved %s', display_path(download_location))
+
+
+def unpack_http_url(
+    link,  # type: Link
+    location,  # type: str
+    downloader,  # type: Downloader
+    download_dir=None,  # type: Optional[str]
+    hashes=None,  # type: Optional[Hashes]
+):
+    # type: (...) -> str
+    temp_dir = TempDirectory(kind="unpack", globally_managed=True)
+    # If a download dir is specified, is the file already downloaded there?
+    already_downloaded_path = None
+    if download_dir:
+        already_downloaded_path = _check_download_dir(
+            link, download_dir, hashes
+        )
+
+    if already_downloaded_path:
+        from_path = already_downloaded_path
+        content_type = mimetypes.guess_type(from_path)[0]
+    else:
+        # let's download to a tmp dir
+        from_path, content_type = _download_http_url(
+            link, downloader, temp_dir.path, hashes
+        )
+
+    # unpack the archive to the build dir location. even when only
+    # downloading archives, they have to be unpacked to parse dependencies
+    unpack_file(from_path, location, content_type)
+
+    return from_path
+
+
+def _copy2_ignoring_special_files(src, dest):
+    # type: (str, str) -> None
+    """Copying special files is not supported, but as a convenience to users
+    we skip errors copying them. This supports tools that may create e.g.
+    socket files in the project source directory.
+    """
+    try:
+        copy2_fixed(src, dest)
+    except shutil.SpecialFileError as e:
+        # SpecialFileError may be raised due to either the source or
+        # destination. If the destination was the cause then we would actually
+        # care, but since the destination directory is deleted prior to
+        # copy we ignore all of them assuming it is caused by the source.
+        logger.warning(
+            "Ignoring special file error '%s' encountered copying %s to %s.",
+            str(e),
+            path_to_display(src),
+            path_to_display(dest),
+        )
+
+
+def _copy_source_tree(source, target):
+    # type: (str, str) -> None
+    def ignore(d, names):
+        # type: (str, List[str]) -> List[str]
+        # Pulling in those directories can potentially be very slow,
+        # exclude the following directories if they appear in the top
+        # level dir (and only it).
+        # See discussion at https://github.com/pypa/pip/pull/6770
+        return ['.tox', '.nox'] if d == source else []
+
+    kwargs = dict(ignore=ignore, symlinks=True)  # type: CopytreeKwargs
+
+    if not PY2:
+        # Python 2 does not support copy_function, so we only ignore
+        # errors on special file copy in Python 3.
+        kwargs['copy_function'] = _copy2_ignoring_special_files
+
+    shutil.copytree(source, target, **kwargs)
+
+
+def unpack_file_url(
+    link,  # type: Link
+    location,  # type: str
+    download_dir=None,  # type: Optional[str]
+    hashes=None  # type: Optional[Hashes]
+):
+    # type: (...) -> Optional[str]
+    """Unpack link into location.
+    """
+    link_path = link.file_path
+    # If it's a url to a local directory
+    if link.is_existing_dir():
+        if os.path.isdir(location):
+            rmtree(location)
+        _copy_source_tree(link_path, location)
+        return None
+
+    # If a download dir is specified, is the file already there and valid?
+    already_downloaded_path = None
+    if download_dir:
+        already_downloaded_path = _check_download_dir(
+            link, download_dir, hashes
+        )
+
+    if already_downloaded_path:
+        from_path = already_downloaded_path
+    else:
+        from_path = link_path
+
+    # If --require-hashes is off, `hashes` is either empty, the
+    # link's embedded hash, or MissingHashes; it is required to
+    # match. If --require-hashes is on, we are satisfied by any
+    # hash in `hashes` matching: a URL-based or an option-based
+    # one; no internet-sourced hash will be in `hashes`.
+    if hashes:
+        hashes.check_against_path(from_path)
+
+    content_type = mimetypes.guess_type(from_path)[0]
+
+    # unpack the archive to the build dir location. even when only downloading
+    # archives, they have to be unpacked to parse dependencies
+    unpack_file(from_path, location, content_type)
+
+    return from_path
+
+
+def unpack_url(
+    link,  # type: Link
+    location,  # type: str
+    downloader,  # type: Downloader
+    download_dir=None,  # type: Optional[str]
+    hashes=None,  # type: Optional[Hashes]
+):
+    # type: (...) -> Optional[str]
+    """Unpack link into location, downloading if required.
+
+    :param hashes: A Hashes object, one of whose embedded hashes must match,
+        or HashMismatch will be raised. If the Hashes is empty, no matches are
+        required, and unhashable types of requirements (like VCS ones, which
+        would ordinarily raise HashUnsupported) are allowed.
+    """
+    # non-editable vcs urls
+    if link.is_vcs:
+        unpack_vcs_link(link, location)
+        return None
+
+    # file urls
+    elif link.is_file:
+        return unpack_file_url(link, location, download_dir, hashes=hashes)
+
+    # http urls
+    else:
+        return unpack_http_url(
+            link,
+            location,
+            downloader,
+            download_dir,
+            hashes=hashes,
+        )
+
+
+def _download_http_url(
+    link,  # type: Link
+    downloader,  # type: Downloader
+    temp_dir,  # type: str
+    hashes,  # type: Optional[Hashes]
+):
+    # type: (...) -> Tuple[str, str]
+    """Download link url into temp_dir using provided session"""
+    download = downloader(link)
+
+    file_path = os.path.join(temp_dir, download.filename)
+    with open(file_path, 'wb') as content_file:
+        for chunk in download.chunks:
+            content_file.write(chunk)
+
+    if hashes:
+        hashes.check_against_path(file_path)
+
+    return file_path, download.response.headers.get('content-type', '')
+
+
+def _check_download_dir(link, download_dir, hashes):
+    # type: (Link, str, Optional[Hashes]) -> Optional[str]
+    """ Check download_dir for previously downloaded file with correct hash
+        If a correct file is found return its path else None
+    """
+    download_path = os.path.join(download_dir, link.filename)
+
+    if not os.path.exists(download_path):
+        return None
+
+    # If already downloaded, does its hash match?
+    logger.info('File was already downloaded %s', download_path)
+    if hashes:
+        try:
+            hashes.check_against_path(download_path)
+        except HashMismatch:
+            logger.warning(
+                'Previously-downloaded file %s has bad hash. '
+                'Re-downloading.',
+                download_path
+            )
+            os.unlink(download_path)
+            return None
+    return download_path
+
+
+class RequirementPreparer(object):
+    """Prepares a Requirement
+    """
+
+    def __init__(
+        self,
+        build_dir,  # type: str
+        download_dir,  # type: Optional[str]
+        src_dir,  # type: str
+        wheel_download_dir,  # type: Optional[str]
+        build_isolation,  # type: bool
+        req_tracker,  # type: RequirementTracker
+        downloader,  # type: Downloader
+        finder,  # type: PackageFinder
+        require_hashes,  # type: bool
+        use_user_site,  # type: bool
+    ):
+        # type: (...) -> None
+        super(RequirementPreparer, self).__init__()
+
+        self.src_dir = src_dir
+        self.build_dir = build_dir
+        self.req_tracker = req_tracker
+        self.downloader = downloader
+        self.finder = finder
+
+        # Where still-packed archives should be written to. If None, they are
+        # not saved, and are deleted immediately after unpacking.
+        self.download_dir = download_dir
+
+        # Where still-packed .whl files should be written to. If None, they are
+        # written to the download_dir parameter. Separate to download_dir to
+        # permit only keeping wheel archives for pip wheel.
+        self.wheel_download_dir = wheel_download_dir
+
+        # NOTE
+        # download_dir and wheel_download_dir overlap semantically and may
+        # be combined if we're willing to have non-wheel archives present in
+        # the wheelhouse output by 'pip wheel'.
+
+        # Is build isolation allowed?
+        self.build_isolation = build_isolation
+
+        # Should hash-checking be required?
+        self.require_hashes = require_hashes
+
+        # Should install in user site-packages?
+        self.use_user_site = use_user_site
+
+    @property
+    def _download_should_save(self):
+        # type: () -> bool
+        if not self.download_dir:
+            return False
+
+        if os.path.exists(self.download_dir):
+            return True
+
+        logger.critical('Could not find download directory')
+        raise InstallationError(
+            "Could not find or access download directory '{}'"
+            .format(self.download_dir))
+
+    def prepare_linked_requirement(
+        self,
+        req,  # type: InstallRequirement
+    ):
+        # type: (...) -> AbstractDistribution
+        """Prepare a requirement that would be obtained from req.link
+        """
+        assert req.link
+        link = req.link
+
+        # TODO: Breakup into smaller functions
+        if link.scheme == 'file':
+            path = link.file_path
+            logger.info('Processing %s', display_path(path))
+        else:
+            logger.info('Collecting %s', req.req or req)
+
+        with indent_log():
+            # @@ if filesystem packages are not marked
+            # editable in a req, a non deterministic error
+            # occurs when the script attempts to unpack the
+            # build directory
+            # Since source_dir is only set for editable requirements.
+            assert req.source_dir is None
+            req.ensure_has_source_dir(self.build_dir)
+            # If a checkout exists, it's unwise to keep going.  version
+            # inconsistencies are logged later, but do not fail the
+            # installation.
+            # FIXME: this won't upgrade when there's an existing
+            # package unpacked in `req.source_dir`
+            if os.path.exists(os.path.join(req.source_dir, 'setup.py')):
+                raise PreviousBuildDirError(
+                    "pip can't proceed with requirements '{}' due to a"
+                    " pre-existing build directory ({}). This is "
+                    "likely due to a previous installation that failed"
+                    ". pip is being responsible and not assuming it "
+                    "can delete this. Please delete it and try again."
+                    .format(req, req.source_dir)
+                )
+
+            # Now that we have the real link, we can tell what kind of
+            # requirements we have and raise some more informative errors
+            # than otherwise. (For example, we can raise VcsHashUnsupported
+            # for a VCS URL rather than HashMissing.)
+            if self.require_hashes:
+                # We could check these first 2 conditions inside
+                # unpack_url and save repetition of conditions, but then
+                # we would report less-useful error messages for
+                # unhashable requirements, complaining that there's no
+                # hash provided.
+                if link.is_vcs:
+                    raise VcsHashUnsupported()
+                elif link.is_existing_dir():
+                    raise DirectoryUrlHashUnsupported()
+                if not req.original_link and not req.is_pinned:
+                    # Unpinned packages are asking for trouble when a new
+                    # version is uploaded. This isn't a security check, but
+                    # it saves users a surprising hash mismatch in the
+                    # future.
+                    #
+                    # file:/// URLs aren't pinnable, so don't complain
+                    # about them not being pinned.
+                    raise HashUnpinned()
+
+            hashes = req.hashes(trust_internet=not self.require_hashes)
+            if self.require_hashes and not hashes:
+                # Known-good hashes are missing for this requirement, so
+                # shim it with a facade object that will provoke hash
+                # computation and then raise a HashMissing exception
+                # showing the user what the hash should be.
+                hashes = MissingHashes()
+
+            download_dir = self.download_dir
+            if link.is_wheel and self.wheel_download_dir:
+                # when doing 'pip wheel` we download wheels to a
+                # dedicated dir.
+                download_dir = self.wheel_download_dir
+
+            try:
+                local_path = unpack_url(
+                    link, req.source_dir, self.downloader, download_dir,
+                    hashes=hashes,
+                )
+            except requests.HTTPError as exc:
+                logger.critical(
+                    'Could not install requirement %s because of error %s',
+                    req,
+                    exc,
+                )
+                raise InstallationError(
+                    'Could not install requirement {} because of HTTP '
+                    'error {} for URL {}'.format(req, exc, link)
+                )
+
+            # For use in later processing, preserve the file path on the
+            # requirement.
+            if local_path:
+                req.local_file_path = local_path
+
+            if link.is_wheel:
+                if download_dir:
+                    # When downloading, we only unpack wheels to get
+                    # metadata.
+                    autodelete_unpacked = True
+                else:
+                    # When installing a wheel, we use the unpacked
+                    # wheel.
+                    autodelete_unpacked = False
+            else:
+                # We always delete unpacked sdists after pip runs.
+                autodelete_unpacked = True
+            if autodelete_unpacked:
+                write_delete_marker_file(req.source_dir)
+
+            abstract_dist = _get_prepared_distribution(
+                req, self.req_tracker, self.finder, self.build_isolation,
+            )
+
+            if download_dir:
+                if link.is_existing_dir():
+                    logger.info('Link is a directory, ignoring download_dir')
+                elif local_path and not os.path.exists(
+                    os.path.join(download_dir, link.filename)
+                ):
+                    _copy_file(local_path, download_dir, link)
+
+            if self._download_should_save:
+                # Make a .zip of the source_dir we already created.
+                if link.is_vcs:
+                    req.archive(self.download_dir)
+        return abstract_dist
+
+    def prepare_editable_requirement(
+        self,
+        req,  # type: InstallRequirement
+    ):
+        # type: (...) -> AbstractDistribution
+        """Prepare an editable requirement
+        """
+        assert req.editable, "cannot prepare a non-editable req as editable"
+
+        logger.info('Obtaining %s', req)
+
+        with indent_log():
+            if self.require_hashes:
+                raise InstallationError(
+                    'The editable requirement {} cannot be installed when '
+                    'requiring hashes, because there is no single file to '
+                    'hash.'.format(req)
+                )
+            req.ensure_has_source_dir(self.src_dir)
+            req.update_editable(not self._download_should_save)
+
+            abstract_dist = _get_prepared_distribution(
+                req, self.req_tracker, self.finder, self.build_isolation,
+            )
+
+            if self._download_should_save:
+                req.archive(self.download_dir)
+            req.check_if_exists(self.use_user_site)
+
+        return abstract_dist
+
+    def prepare_installed_requirement(
+        self,
+        req,  # type: InstallRequirement
+        skip_reason  # type: str
+    ):
+        # type: (...) -> AbstractDistribution
+        """Prepare an already-installed requirement
+        """
+        assert req.satisfied_by, "req should have been satisfied but isn't"
+        assert skip_reason is not None, (
+            "did not get skip reason skipped but req.satisfied_by "
+            "is set to {}".format(req.satisfied_by)
+        )
+        logger.info(
+            'Requirement %s: %s (%s)',
+            skip_reason, req, req.satisfied_by.version
+        )
+        with indent_log():
+            if self.require_hashes:
+                logger.debug(
+                    'Since it is already installed, we are trusting this '
+                    'package without checking its hash. To ensure a '
+                    'completely repeatable environment, install into an '
+                    'empty virtualenv.'
+                )
+            abstract_dist = InstalledDistribution(req)
+
+        return abstract_dist