Viewing file:  readers.py (4.27 KB) -rw-r--r--
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import collections
import itertools
import pathlib
import operator
import zipfile
from . import abc
from ._itertools import only
def remove_duplicates(items):
return iter(collections.OrderedDict.fromkeys(items))
class FileReader(abc.TraversableResources):
def __init__(self, loader):
self.path = pathlib.Path(loader.path).parent
def resource_path(self, resource):
"""
Return the file system path to prevent
`resources.path()` from creating a temporary
copy.
"""
return str(self.path.joinpath(resource))
def files(self):
return self.path
class ZipReader(abc.TraversableResources):
def __init__(self, loader, module):
self.prefix = loader.prefix.replace('\\', '/')
if loader.is_package(module):
_, _, name = module.rpartition('.')
self.prefix += name + '/'
self.archive = loader.archive
def open_resource(self, resource):
try:
return super().open_resource(resource)
except KeyError as exc:
raise FileNotFoundError(exc.args[0])
def is_resource(self, path):
"""
Workaround for `zipfile.Path.is_file` returning true
for non-existent paths.
"""
target = self.files().joinpath(path)
return target.is_file() and target.exists()
def files(self):
return zipfile.Path(self.archive, self.prefix)
class MultiplexedPath(abc.Traversable):
"""
Given a series of Traversable objects, implement a merged
version of the interface across all objects. Useful for
namespace packages which may be multihomed at a single
name.
"""
def __init__(self, *paths):
self._paths = list(map(pathlib.Path, remove_duplicates(paths)))
if not self._paths:
message = 'MultiplexedPath must contain at least one path'
raise FileNotFoundError(message)
if not all(path.is_dir() for path in self._paths):
raise NotADirectoryError('MultiplexedPath only supports directories')
def iterdir(self):
children = (child for path in self._paths for child in path.iterdir())
by_name = operator.attrgetter('name')
groups = itertools.groupby(sorted(children, key=by_name), key=by_name)
return map(self._follow, (locs for name, locs in groups))
def read_bytes(self):
raise FileNotFoundError(f'{self} is not a file')
def read_text(self, *args, **kwargs):
raise FileNotFoundError(f'{self} is not a file')
def is_dir(self):
return True
def is_file(self):
return False
def joinpath(self, *descendants):
try:
return super().joinpath(*descendants)
except abc.TraversalError:
# One of the paths did not resolve (a directory does not exist).
# Just return something that will not exist.
return self._paths[0].joinpath(*descendants)
@classmethod
def _follow(cls, children):
"""
Construct a MultiplexedPath if needed.
If children contains a sole element, return it.
Otherwise, return a MultiplexedPath of the items.
Unless one of the items is not a Directory, then return the first.
"""
subdirs, one_dir, one_file = itertools.tee(children, 3)
try:
return only(one_dir)
except ValueError:
try:
return cls(*subdirs)
except NotADirectoryError:
return next(one_file)
def open(self, *args, **kwargs):
raise FileNotFoundError(f'{self} is not a file')
@property
def name(self):
return self._paths[0].name
def __repr__(self):
paths = ', '.join(f"'{path}'" for path in self._paths)
return f'MultiplexedPath({paths})'
class NamespaceReader(abc.TraversableResources):
def __init__(self, namespace_path):
if 'NamespacePath' not in str(namespace_path):
raise ValueError('Invalid path')
self.path = MultiplexedPath(*list(namespace_path))
def resource_path(self, resource):
"""
Return the file system path to prevent
`resources.path()` from creating a temporary
copy.
"""
return str(self.path.joinpath(resource))
def files(self):
return self.path
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