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# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""Utilities to paste over differences between Python versions."""
from __future__ import absolute_import
from __future__ import print_function
import re
_packaging_lib = None
PACKAGING_LIB_PACKAGING = 'packaging'
PACKAGING_LIB_LEGACY = 'pkg_resources'
def _get_packaging_lib():
global _packaging_lib
if _packaging_lib is not None:
return _packaging_lib
# packaging should almost always be available since setuptools vendors it
# and has done so since forever
#
# https://github.com/pypa/setuptools/commit/84c9006110e53c84296a05741edb7b9edd305f12
try:
import packaging # noqa
_packaging_lib = PACKAGING_LIB_PACKAGING
return _packaging_lib
except ImportError:
pass
# pkg_resources is our fallback. This will always be available on older
# Python versions since it's part of setuptools.
try:
import pkg_resources # noqa
_packaging_lib = PACKAGING_LIB_LEGACY
return _packaging_lib
except ImportError:
pass
raise RuntimeError(
'Failed to find a library for parsing packaging information. This '
'should not happen. Please report a bug against pbr.'
)
def extract_project_name(requirement_line):
packaging_lib = _get_packaging_lib()
if packaging_lib == PACKAGING_LIB_PACKAGING:
import packaging.requirements
try:
requirement = packaging.requirements.Requirement(requirement_line)
except ValueError:
return None
# the .project_name attribute is not part of the
# packaging.requirements.Requirement API so we mimic it
#
# https://github.com/pypa/setuptools/blob/v80.9.0/pkg_resources/__init__.py#L2918
return re.sub('[^A-Za-z0-9.]+', '-', requirement.name)
else: # PACKAGING_LIB_LEGACY
import pkg_resources
try:
requirement = pkg_resources.Requirement.parse(requirement_line)
except ValueError:
return None
return requirement.project_name
def parse_version(version):
packaging_lib = _get_packaging_lib()
if packaging_lib == PACKAGING_LIB_PACKAGING:
import packaging.version
return packaging.version.Version(version)
else: # PACKAGING_LIB_LEGACY
import pkg_resources
return pkg_resources.parse_version(version)
def evaluate_marker(marker):
packaging_lib = _get_packaging_lib()
if packaging_lib == PACKAGING_LIB_PACKAGING:
import packaging.markers
try:
return packaging.markers.Marker(marker).evaluate()
except packaging.markers.InvalidMarker as e:
# setuptools expects a SyntaxError here, so we do the same.
# we can't chain the exceptions since that is a Python 3 only thing
raise SyntaxError(e)
else: # PACKAGING_LIB_LEGACY
import pkg_resources
return pkg_resources.evaluate_marker(marker)
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