File: //usr/lib/python3/dist-packages/pip/_internal/distributions/base.py
import abc
from pip._internal.index.package_finder import PackageFinder
from pip._internal.metadata.base import BaseDistribution
from pip._internal.req import InstallRequirement
class AbstractDistribution(metaclass=abc.ABCMeta):
    """A base class for handling installable artifacts.
    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).
     - 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: InstallRequirement) -> None:
        super().__init__()
        self.req = req
    @abc.abstractmethod
    def get_metadata_distribution(self) -> BaseDistribution:
        raise NotImplementedError()
    @abc.abstractmethod
    def prepare_distribution_metadata(
        self, finder: PackageFinder, build_isolation: bool
    ) -> None:
        raise NotImplementedError()