nzbToMedia/libs/win/importlib_metadata/_hooks.py
2018-12-16 13:50:35 -05:00

148 lines
4.2 KiB
Python

from __future__ import unicode_literals, absolute_import
import re
import sys
import itertools
from .api import Distribution
from zipfile import ZipFile
if sys.version_info >= (3,): # pragma: nocover
from contextlib import suppress
from pathlib import Path
else: # pragma: nocover
from contextlib2 import suppress # noqa
from itertools import imap as map # type: ignore
from pathlib2 import Path
FileNotFoundError = IOError, OSError
__metaclass__ = type
def install(cls):
"""Class decorator for installation on sys.meta_path."""
sys.meta_path.append(cls)
return cls
class NullFinder:
@staticmethod
def find_spec(*args, **kwargs):
return None
# In Python 2, the import system requires finders
# to have a find_module() method, but this usage
# is deprecated in Python 3 in favor of find_spec().
# For the purposes of this finder (i.e. being present
# on sys.meta_path but having no other import
# system functionality), the two methods are identical.
find_module = find_spec
@install
class MetadataPathFinder(NullFinder):
"""A degenerate finder for distribution packages on the file system.
This finder supplies only a find_distribution() method for versions
of Python that do not have a PathFinder find_distribution().
"""
search_template = r'{name}(-.*)?\.(dist|egg)-info'
@classmethod
def find_distribution(cls, name):
paths = cls._search_paths(name)
dists = map(PathDistribution, paths)
return next(dists, None)
@classmethod
def _search_paths(cls, name):
"""
Find metadata directories in sys.path heuristically.
"""
return itertools.chain.from_iterable(
cls._search_path(path, name)
for path in map(Path, sys.path)
)
@classmethod
def _search_path(cls, root, name):
if not root.is_dir():
return ()
normalized = name.replace('-', '_')
return (
item
for item in root.iterdir()
if item.is_dir()
and re.match(
cls.search_template.format(name=normalized),
str(item.name),
flags=re.IGNORECASE,
)
)
class PathDistribution(Distribution):
def __init__(self, path):
"""Construct a distribution from a path to the metadata directory."""
self._path = path
def read_text(self, filename):
with suppress(FileNotFoundError):
with self._path.joinpath(filename).open(encoding='utf-8') as fp:
return fp.read()
return None
read_text.__doc__ = Distribution.read_text.__doc__
@install
class WheelMetadataFinder(NullFinder):
"""A degenerate finder for distribution packages in wheels.
This finder supplies only a find_distribution() method for versions
of Python that do not have a PathFinder find_distribution().
"""
search_template = r'{name}(-.*)?\.whl'
@classmethod
def find_distribution(cls, name):
paths = cls._search_paths(name)
dists = map(WheelDistribution, paths)
return next(dists, None)
@classmethod
def _search_paths(cls, name):
return (
item
for item in map(Path, sys.path)
if re.match(
cls.search_template.format(name=name),
str(item.name),
flags=re.IGNORECASE,
)
)
class WheelDistribution(Distribution):
def __init__(self, archive):
self._archive = archive
name, version = archive.name.split('-')[0:2]
self._dist_info = '{}-{}.dist-info'.format(name, version)
def read_text(self, filename):
with ZipFile(_path_to_filename(self._archive)) as zf:
with suppress(KeyError):
as_bytes = zf.read('{}/{}'.format(self._dist_info, filename))
return as_bytes.decode('utf-8')
return None
read_text.__doc__ = Distribution.read_text.__doc__
def _path_to_filename(path): # pragma: nocover
"""
On non-compliant systems, ensure a path-like object is
a string.
"""
try:
return path.__fspath__()
except AttributeError:
return str(path)