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stbi/Lib/site-packages/pip/_internal/utils/packaging.py

+from __future__ import absolute_import
+
+import logging
+from email.parser import FeedParser
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging import specifiers, version
+
+from pip._internal.exceptions import NoneMetadataError
+from pip._internal.utils.misc import display_path
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Tuple
+    from email.message import Message
+    from pip._vendor.pkg_resources import Distribution
+
+
+logger = logging.getLogger(__name__)
+
+
+def check_requires_python(requires_python, version_info):
+    # type: (Optional[str], 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):
+    # type: (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_requires_python(dist):
+    # type: (pkg_resources.Distribution) -> Optional[str]
+    """
+    Return the "Requires-Python" metadata for a distribution, or None
+    if not present.
+    """
+    pkg_info_dict = get_metadata(dist)
+    requires_python = pkg_info_dict.get('Requires-Python')
+
+    if requires_python is not None:
+        # Convert to a str to satisfy the type checker, since requires_python
+        # can be a Header object.
+        requires_python = str(requires_python)
+
+    return requires_python
+
+
+def get_installer(dist):
+    # type: (Distribution) -> str
+    if dist.has_metadata('INSTALLER'):
+        for line in dist.get_metadata_lines('INSTALLER'):
+            if line.strip():
+                return line.strip()
+    return ''