Na}{

File Content: `packaging.py`

import functools
import logging
from email.message import Message
from email.parser import FeedParser
from typing import Optional, Tuple

from pip._vendor import pkg_resources
from pip._vendor.packaging import specifiers, version
from pip._vendor.packaging.requirements import Requirement
from pip._vendor.pkg_resources import Distribution

from pip._internal.exceptions import NoneMetadataError
from pip._internal.utils.misc import display_path

logger = logging.getLogger(__name__)


def check_requires_python(
    requires_python: Optional[str], version_info: Tuple[int, ...]
) -> bool:
    """
    Check if the given Python version matches a "Requires-Python" specifier.

    :param version_info: A 3-tuple of ints representing a Python
        major-minor-micro version to check (e.g. `sys.version_info[:3]`).

    :return: `True` if the given Python version satisfies the requirement.
        Otherwise, return `False`.

    :raises InvalidSpecifier: If `requires_python` has an invalid format.
    """
    if requires_python is None:
        # The package provides no information
        return True
    requires_python_specifier = specifiers.SpecifierSet(requires_python)

    python_version = version.parse(".".join(map(str, version_info)))
    return python_version in requires_python_specifier


def get_metadata(dist: Distribution) -> Message:
    """
    :raises NoneMetadataError: if the distribution reports `has_metadata()`
        True but `get_metadata()` returns None.
    """
    metadata_name = "METADATA"
    if isinstance(dist, pkg_resources.DistInfoDistribution) and dist.has_metadata(
        metadata_name
    ):
        metadata = dist.get_metadata(metadata_name)
    elif dist.has_metadata("PKG-INFO"):
        metadata_name = "PKG-INFO"
        metadata = dist.get_metadata(metadata_name)
    else:
        logger.warning("No metadata found in %s", display_path(dist.location))
        metadata = ""

    if metadata is None:
        raise NoneMetadataError(dist, metadata_name)

    feed_parser = FeedParser()
    # The following line errors out if with a "NoneType" TypeError if
    # passed metadata=None.
    feed_parser.feed(metadata)
    return feed_parser.close()


def get_installer(dist: Distribution) -> str:
    if dist.has_metadata("INSTALLER"):
        for line in dist.get_metadata_lines("INSTALLER"):
            if line.strip():
                return line.strip()
    return ""


@functools.lru_cache(maxsize=512)
def get_requirement(req_string: str) -> Requirement:
    """Construct a packaging.Requirement object with caching"""
    # Parsing requirement strings is expensive, and is also expected to happen
    # with a low diversity of different arguments (at least relative the number
    # constructed). This method adds a cache to requirement object creation to
    # minimize repeated parsing of the same string to construct equivalent
    # Requirement objects.
    return Requirement(req_string)

Name	Size	Permission
__pycache__	---	0755
__init__.py	0 bytes	0644
_log.py	1015 bytes	0644
appdirs.py	1665 bytes	0644
compat.py	1884 bytes	0644
compatibility_tags.py	5377 bytes	0644
datetime.py	242 bytes	0644
deprecation.py	3627 bytes	0644
direct_url_helpers.py	3206 bytes	0644
distutils_args.py	1249 bytes	0644
egg_link.py	2203 bytes	0644
encoding.py	1169 bytes	0644
entrypoints.py	1055 bytes	0644
filesystem.py	5893 bytes	0644
filetypes.py	716 bytes	0644
glibc.py	3110 bytes	0644
hashes.py	4811 bytes	0644
inject_securetransport.py	795 bytes	0644
logging.py	11532 bytes	0644
misc.py	20432 bytes	0644
models.py	1193 bytes	0644
packaging.py	2952 bytes	0644
parallel.py	3196 bytes	0644
pkg_resources.py	987 bytes	0644
setuptools_build.py	4697 bytes	0644
subprocess.py	10058 bytes	0644
temp_dir.py	7662 bytes	0644
unpacking.py	8906 bytes	0644
urls.py	1759 bytes	0644
virtualenv.py	3459 bytes	0644
wheel.py	6163 bytes	0644

File Content: packaging.py

File Content: `packaging.py`