4 files changed, 738 insertions, 0 deletions
diff --git a/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/__init__.py b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/__init__.py
diff --git a/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/check.py b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/check.py
new file mode 100644
index 0000000..bab6b9f
--- /dev/null
+++ b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/check.py
@@ -0,0 +1,106 @@
+"""Validation of dependencies of packages
+"""
+from collections import namedtuple
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._internal.operations.prepare import make_abstract_dist
+from pip._internal.utils.misc import get_installed_distributions
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+if MYPY_CHECK_RUNNING:
+    from pip._internal.req.req_install import InstallRequirement
+    from typing import Any, Dict, Iterator, Set, Tuple, List
+    # Shorthands
+    PackageSet = Dict[str, 'PackageDetails']
+    Missing = Tuple[str, Any]
+    Conflicting = Tuple[str, str, Any]
+    MissingDict = Dict[str, List[Missing]]
+    ConflictingDict = Dict[str, List[Conflicting]]
+    CheckResult = Tuple[MissingDict, ConflictingDict]
+PackageDetails = namedtuple('PackageDetails', ['version', 'requires'])
+def create_package_set_from_installed(**kwargs):
+    # type: (**Any) -> PackageSet
+    """Converts a list of distributions into a PackageSet.
+    """
+    # Default to using all packages installed on the system
+    if kwargs == {}:
+        kwargs = {"local_only": False, "skip": ()}
+    retval = {}
+    for dist in get_installed_distributions(**kwargs):
+        name = canonicalize_name(dist.project_name)
+        retval[name] = PackageDetails(dist.version, dist.requires())
+    return retval
+def check_package_set(package_set):
+    # type: (PackageSet) -> CheckResult
+    """Check if a package set is consistent
+    """
+    missing = dict()
+    conflicting = dict()
+    for package_name in package_set:
+        # Info about dependencies of package_name
+        missing_deps = set()  # type: Set[Missing]
+        conflicting_deps = set()  # type: Set[Conflicting]
+        for req in package_set[package_name].requires:
+            name = canonicalize_name(req.project_name)  # type: str
+            # Check if it's missing
+            if name not in package_set:
+                missed = True
+                if req.marker is not None:
+                    missed = req.marker.evaluate()
+                if missed:
+                    missing_deps.add((name, req))
+                continue
+            # Check if there's a conflict
+            version = package_set[name].version  # type: str
+            if not req.specifier.contains(version, prereleases=True):
+                conflicting_deps.add((name, version, req))
+        def str_key(x):
+            return str(x)
+        if missing_deps:
+            missing[package_name] = sorted(missing_deps, key=str_key)
+        if conflicting_deps:
+            conflicting[package_name] = sorted(conflicting_deps, key=str_key)
+    return missing, conflicting
+def check_install_conflicts(to_install):
+    # type: (List[InstallRequirement]) -> Tuple[PackageSet, CheckResult]
+    """For checking if the dependency graph would be consistent after \
+    installing given requirements
+    """
+    # Start from the current state
+    state = create_package_set_from_installed()
+    _simulate_installation_of(to_install, state)
+    return state, check_package_set(state)
+# NOTE from @pradyunsg
+# This required a minor update in dependency link handling logic over at
+# operations.prepare.IsSDist.dist() to get it working
+def _simulate_installation_of(to_install, state):
+    # type: (List[InstallRequirement], PackageSet) -> None
+    """Computes the version of packages after installing to_install.
+    """
+    # Modify it as installing requirement_set would (assuming no errors)
+    for inst_req in to_install:
+        dist = make_abstract_dist(inst_req).dist(finder=None)
+        name = canonicalize_name(dist.key)
+        state[name] = PackageDetails(dist.version, dist.requires())
diff --git a/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/freeze.py b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/freeze.py
new file mode 100644
index 0000000..000102d
--- /dev/null
+++ b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/freeze.py
@@ -0,0 +1,252 @@
+from __future__ import absolute_import
+import collections
+import logging
+import os
+import re
+import warnings
+from pip._vendor import pkg_resources, six
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.pkg_resources import RequirementParseError
+from pip._internal.exceptions import InstallationError
+from pip._internal.req import InstallRequirement
+from pip._internal.req.req_file import COMMENT_RE
+from pip._internal.utils.deprecation import RemovedInPip11Warning
+from pip._internal.utils.misc import (
+    dist_is_editable, get_installed_distributions,
+)
+logger = logging.getLogger(__name__)
+def freeze(
+        requirement=None,
+        find_links=None, local_only=None, user_only=None, skip_regex=None,
+        isolated=False,
+        wheel_cache=None,
+        exclude_editable=False,
+        skip=()):
+    find_links = find_links or []
+    skip_match = None
+    if skip_regex:
+        skip_match = re.compile(skip_regex).search
+    dependency_links = []
+    for dist in pkg_resources.working_set:
+        if dist.has_metadata('dependency_links.txt'):
+            dependency_links.extend(
+                dist.get_metadata_lines('dependency_links.txt')
+            )
+    for link in find_links:
+        if '#egg=' in link:
+            dependency_links.append(link)
+    for link in find_links:
+        yield '-f %s' % link
+    installations = {}
+    for dist in get_installed_distributions(local_only=local_only,
+                                            skip=(),
+                                            user_only=user_only):
+        try:
+            req = FrozenRequirement.from_dist(
+                dist,
+                dependency_links
+            )
+        except RequirementParseError:
+            logger.warning(
+                "Could not parse requirement: %s",
+                dist.project_name
+            )
+            continue
+        if exclude_editable and req.editable:
+            continue
+        installations[req.name] = req
+    if requirement:
+        # the options that don't get turned into an InstallRequirement
+        # should only be emitted once, even if the same option is in multiple
+        # requirements files, so we need to keep track of what has been emitted
+        # so that we don't emit it again if it's seen again
+        emitted_options = set()
+        # keep track of which files a requirement is in so that we can
+        # give an accurate warning if a requirement appears multiple times.
+        req_files = collections.defaultdict(list)
+        for req_file_path in requirement:
+            with open(req_file_path) as req_file:
+                for line in req_file:
+                    if (not line.strip() or
+                            line.strip().startswith('#') or
+                            (skip_match and skip_match(line)) or
+                            line.startswith((
+                                '-r', '--requirement',
+                                '-Z', '--always-unzip',
+                                '-f', '--find-links',
+                                '-i', '--index-url',
+                                '--pre',
+                                '--trusted-host',
+                                '--process-dependency-links',
+                                '--extra-index-url'))):
+                        line = line.rstrip()
+                        if line not in emitted_options:
+                            emitted_options.add(line)
+                            yield line
+                        continue
+                    if line.startswith('-e') or line.startswith('--editable'):
+                        if line.startswith('-e'):
+                            line = line[2:].strip()
+                        else:
+                            line = line[len('--editable'):].strip().lstrip('=')
+                        line_req = InstallRequirement.from_editable(
+                            line,
+                            isolated=isolated,
+                            wheel_cache=wheel_cache,
+                        )
+                    else:
+                        line_req = InstallRequirement.from_line(
+                            COMMENT_RE.sub('', line).strip(),
+                            isolated=isolated,
+                            wheel_cache=wheel_cache,
+                        )
+                    if not line_req.name:
+                        logger.info(
+                            "Skipping line in requirement file [%s] because "
+                            "it's not clear what it would install: %s",
+                            req_file_path, line.strip(),
+                        )
+                        logger.info(
+                            "  (add #egg=PackageName to the URL to avoid"
+                            " this warning)"
+                        )
+                    elif line_req.name not in installations:
+                        # either it's not installed, or it is installed
+                        # but has been processed already
+                        if not req_files[line_req.name]:
+                            logger.warning(
+                                "Requirement file [%s] contains %s, but that "
+                                "package is not installed",
+                                req_file_path,
+                                COMMENT_RE.sub('', line).strip(),
+                            )
+                        else:
+                            req_files[line_req.name].append(req_file_path)
+                    else:
+                        yield str(installations[line_req.name]).rstrip()
+                        del installations[line_req.name]
+                        req_files[line_req.name].append(req_file_path)
+        # Warn about requirements that were included multiple times (in a
+        # single requirements file or in different requirements files).
+        for name, files in six.iteritems(req_files):
+            if len(files) > 1:
+                logger.warning("Requirement %s included multiple times [%s]",
+                               name, ', '.join(sorted(set(files))))
+        yield(
+            '## The following requirements were added by '
+            'pip freeze:'
+        )
+    for installation in sorted(
+            installations.values(), key=lambda x: x.name.lower()):
+        if canonicalize_name(installation.name) not in skip:
+            yield str(installation).rstrip()
+class FrozenRequirement(object):
+    def __init__(self, name, req, editable, comments=()):
+        self.name = name
+        self.req = req
+        self.editable = editable
+        self.comments = comments
+    _rev_re = re.compile(r'-r(\d+)$')
+    _date_re = re.compile(r'-(20\d\d\d\d\d\d)$')
+    @classmethod
+    def from_dist(cls, dist, dependency_links):
+        location = os.path.normcase(os.path.abspath(dist.location))
+        comments = []
+        from pip._internal.vcs import vcs, get_src_requirement
+        if dist_is_editable(dist) and vcs.get_backend_name(location):
+            editable = True
+            try:
+                req = get_src_requirement(dist, location)
+            except InstallationError as exc:
+                logger.warning(
+                    "Error when trying to get requirement for VCS system %s, "
+                    "falling back to uneditable format", exc
+                )
+                req = None
+            if req is None:
+                logger.warning(
+                    'Could not determine repository location of %s', location
+                )
+                comments.append(
+                    '## !! Could not determine repository location'
+                )
+                req = dist.as_requirement()
+                editable = False
+        else:
+            editable = False
+            req = dist.as_requirement()
+            specs = req.specs
+            assert len(specs) == 1 and specs[0][0] in ["==", "==="], \
+                'Expected 1 spec with == or ===; specs = %r; dist = %r' % \
+                (specs, dist)
+            version = specs[0][1]
+            ver_match = cls._rev_re.search(version)
+            date_match = cls._date_re.search(version)
+            if ver_match or date_match:
+                svn_backend = vcs.get_backend('svn')
+                if svn_backend:
+                    svn_location = svn_backend().get_location(
+                        dist,
+                        dependency_links,
+                    )
+                if not svn_location:
+                    logger.warning(
+                        'Warning: cannot find svn location for %s', req,
+                    )
+                    comments.append(
+                        '## FIXME: could not find svn URL in dependency_links '
+                        'for this package:'
+                    )
+                else:
+                    warnings.warn(
+                        "SVN editable detection based on dependency links "
+                        "will be dropped in the future.",
+                        RemovedInPip11Warning,
+                    )
+                    comments.append(
+                        '# Installing as editable to satisfy requirement %s:' %
+                        req
+                    )
+                    if ver_match:
+                        rev = ver_match.group(1)
+                    else:
+                        rev = '{%s}' % date_match.group(1)
+                    editable = True
+                    req = '%s@%s#egg=%s' % (
+                        svn_location,
+                        rev,
+                        cls.egg_name(dist)
+                    )
+        return cls(dist.project_name, req, editable, comments)
+    @staticmethod
+    def egg_name(dist):
+        name = dist.egg_name()
+        match = re.search(r'-py\d\.\d$', name)
+        if match:
+            name = name[:match.start()]
+        return name
+    def __str__(self):
+        req = self.req
+        if self.editable:
+            req = '-e %s' % req
+        return '\n'.join(list(self.comments) + [str(req)]) + '\n'
diff --git a/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/prepare.py b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/prepare.py
new file mode 100644
index 0000000..c1e8158
--- /dev/null
+++ b/venv/lib/python3.7/site-packages/pip-10.0.1-py3.7.egg/pip/_internal/operations/prepare.py
@@ -0,0 +1,380 @@
+"""Prepares a distribution for installation
+"""
+import itertools
+import logging
+import os
+import sys
+from copy import copy
+from pip._vendor import pkg_resources, requests
+from pip._internal.build_env import NoOpBuildEnvironment
+from pip._internal.compat import expanduser
+from pip._internal.download import (
+    is_dir_url, is_file_url, is_vcs_url, unpack_url, url_to_path,
+)
+from pip._internal.exceptions import (
+    DirectoryUrlHashUnsupported, HashUnpinned, InstallationError,
+    PreviousBuildDirError, VcsHashUnsupported,
+)
+from pip._internal.index import FormatControl
+from pip._internal.req.req_install import InstallRequirement
+from pip._internal.utils.hashes import MissingHashes
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import (
+    call_subprocess, display_path, normalize_path,
+)
+from pip._internal.utils.ui import open_spinner
+from pip._internal.vcs import vcs
+logger = logging.getLogger(__name__)
+def make_abstract_dist(req):
+    """Factory to make an abstract dist object.
+    Preconditions: Either an editable req with a source_dir, or satisfied_by or
+    a wheel link, or a non-editable req with a source_dir.
+    :return: A concrete DistAbstraction.
+    """
+    if req.editable:
+        return IsSDist(req)
+    elif req.link and req.link.is_wheel:
+        return IsWheel(req)
+    else:
+        return IsSDist(req)
+def _install_build_reqs(finder, prefix, build_requirements):
+    # NOTE: What follows is not a very good thing.
+    #       Eventually, this should move into the BuildEnvironment class and
+    #       that should handle all the isolation and sub-process invocation.
+    finder = copy(finder)
+    finder.format_control = FormatControl(set(), set([":all:"]))
+    urls = [
+        finder.find_requirement(
+            InstallRequirement.from_line(r), upgrade=False).url
+        for r in build_requirements
+    ]
+    args = [
+        sys.executable, '-m', 'pip', 'install', '--ignore-installed',
+        '--no-user', '--prefix', prefix,
+    ] + list(urls)
+    with open_spinner("Installing build dependencies") as spinner:
+        call_subprocess(args, show_stdout=False, spinner=spinner)
+class DistAbstraction(object):
+    """Abstracts out the wheel vs non-wheel Resolver.resolve() logic.
+    The requirements for anything installable are as follows:
+     - we must be able to determine the requirement name
+       (or we can't correctly handle the non-upgrade case).
+     - we must be able to generate a list of run-time dependencies
+       without installing any additional packages (or we would
+       have to either burn time by doing temporary isolated installs
+       or alternatively violate pips 'don't start installing unless
+       all requirements are available' rule - neither of which are
+       desirable).
+     - for packages with setup requirements, we must also be able
+       to determine their requirements without installing additional
+       packages (for the same reason as run-time dependencies)
+     - we must be able to create a Distribution object exposing the
+       above metadata.
+    """
+    def __init__(self, req):
+        self.req = req
+    def dist(self, finder):
+        """Return a setuptools Dist object."""
+        raise NotImplementedError(self.dist)
+    def prep_for_dist(self, finder):
+        """Ensure that we can get a Dist for this requirement."""
+        raise NotImplementedError(self.dist)
+class IsWheel(DistAbstraction):
+    def dist(self, finder):
+        return list(pkg_resources.find_distributions(
+            self.req.source_dir))[0]
+    def prep_for_dist(self, finder, build_isolation):
+        # FIXME:https://github.com/pypa/pip/issues/1112
+        pass
+class IsSDist(DistAbstraction):
+    def dist(self, finder):
+        dist = self.req.get_dist()
+        # FIXME: shouldn't be globally added.
+        if finder and dist.has_metadata('dependency_links.txt'):
+            finder.add_dependency_links(
+                dist.get_metadata_lines('dependency_links.txt')
+            )
+        return dist
+    def prep_for_dist(self, finder, build_isolation):
+        # Before calling "setup.py egg_info", we need to set-up the build
+        # environment.
+        build_requirements, isolate = self.req.get_pep_518_info()
+        should_isolate = build_isolation and isolate
+        minimum_requirements = ('setuptools', 'wheel')
+        missing_requirements = set(minimum_requirements) - set(
+            pkg_resources.Requirement(r).key
+            for r in build_requirements
+        )
+        if missing_requirements:
+            def format_reqs(rs):
+                return ' and '.join(map(repr, sorted(rs)))
+            logger.warning(
+                "Missing build time requirements in pyproject.toml for %s: "
+                "%s.", self.req, format_reqs(missing_requirements)
+            )
+            logger.warning(
+                "This version of pip does not implement PEP 517 so it cannot "
+                "build a wheel without %s.", format_reqs(minimum_requirements)
+            )
+        if should_isolate:
+            with self.req.build_env:
+                pass
+            _install_build_reqs(finder, self.req.build_env.path,
+                                build_requirements)
+        else:
+            self.req.build_env = NoOpBuildEnvironment(no_clean=False)
+        self.req.run_egg_info()
+        self.req.assert_source_matches_version()
+class Installed(DistAbstraction):
+    def dist(self, finder):
+        return self.req.satisfied_by
+    def prep_for_dist(self, finder):
+        pass
+class RequirementPreparer(object):
+    """Prepares a Requirement
+    """
+    def __init__(self, build_dir, download_dir, src_dir, wheel_download_dir,
+                 progress_bar, build_isolation):
+        super(RequirementPreparer, self).__init__()
+        self.src_dir = src_dir
+        self.build_dir = build_dir
+        # 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.
+        if wheel_download_dir:
+            wheel_download_dir = normalize_path(wheel_download_dir)
+        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'.
+        self.progress_bar = progress_bar
+        # Is build isolation allowed?
+        self.build_isolation = build_isolation
+    @property
+    def _download_should_save(self):
+        # TODO: Modify to reduce indentation needed
+        if self.download_dir:
+            self.download_dir = expanduser(self.download_dir)
+            if os.path.exists(self.download_dir):
+                return True
+            else:
+                logger.critical('Could not find download directory')
+                raise InstallationError(
+                    "Could not find or access download directory '%s'"
+                    % display_path(self.download_dir))
+        return False
+    def prepare_linked_requirement(self, req, session, finder,
+                                   upgrade_allowed, require_hashes):
+        """Prepare a requirement that would be obtained from req.link
+        """
+        # TODO: Breakup into smaller functions
+        if req.link and req.link.scheme == 'file':
+            path = url_to_path(req.link.url)
+            logger.info('Processing %s', display_path(path))
+        else:
+            logger.info('Collecting %s', 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
+            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`
+            # 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 '%s' due to a"
+                    " pre-existing build directory (%s). 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."
+                    % (req, req.source_dir)
+                )
+            req.populate_link(finder, upgrade_allowed, require_hashes)
+            # We can't hit this spot and have populate_link return None.
+            # req.satisfied_by is None here (because we're
+            # guarded) and upgrade has no impact except when satisfied_by
+            # is not None.
+            # Then inside find_requirement existing_applicable -> False
+            # If no new versions are found, DistributionNotFound is raised,
+            # otherwise a result is guaranteed.
+            assert req.link
+            link = req.link
+            # 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 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 is_vcs_url(link):
+                    raise VcsHashUnsupported()
+                elif is_file_url(link) and is_dir_url(link):
+                    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 require_hashes)
+            if 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()
+            try:
+                download_dir = self.download_dir
+                # We always delete unpacked sdists after pip ran.
+                autodelete_unpacked = True
+                if req.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
+                if req.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
+                unpack_url(
+                    req.link, req.source_dir,
+                    download_dir, autodelete_unpacked,
+                    session=session, hashes=hashes,
+                    progress_bar=self.progress_bar
+                )
+            except requests.HTTPError as exc:
+                logger.critical(
+                    'Could not install requirement %s because of error %s',
+                    req,
+                    exc,
+                )
+                raise InstallationError(
+                    'Could not install requirement %s because of HTTP '
+                    'error %s for URL %s' %
+                    (req, exc, req.link)
+                )
+            abstract_dist = make_abstract_dist(req)
+            abstract_dist.prep_for_dist(finder, self.build_isolation)
+            if self._download_should_save:
+                # Make a .zip of the source_dir we already created.
+                if req.link.scheme in vcs.all_schemes:
+                    req.archive(self.download_dir)
+        return abstract_dist
+    def prepare_editable_requirement(self, req, require_hashes, use_user_site,
+                                     finder):
+        """Prepare an editable requirement
+        """
+        assert req.editable, "cannot prepare a non-editable req as editable"
+        logger.info('Obtaining %s', req)
+        with indent_log():
+            if require_hashes:
+                raise InstallationError(
+                    'The editable requirement %s cannot be installed when '
+                    'requiring hashes, because there is no single file to '
+                    'hash.' % req
+                )
+            req.ensure_has_source_dir(self.src_dir)
+            req.update_editable(not self._download_should_save)
+            abstract_dist = make_abstract_dist(req)
+            abstract_dist.prep_for_dist(finder, self.build_isolation)
+            if self._download_should_save:
+                req.archive(self.download_dir)
+            req.check_if_exists(use_user_site)
+        return abstract_dist
+    def prepare_installed_requirement(self, req, require_hashes, skip_reason):
+        """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 %r" % (req.satisfied_by,)
+        )
+        logger.info(
+            'Requirement %s: %s (%s)',
+            skip_reason, req, req.satisfied_by.version
+        )
+        with indent_log():
+            if 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 = Installed(req)
+        return abstract_dist