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# Copyright (C) 2009-2016 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""Package and module utilities."""
import os
import sys
from pkg_resources import resource_filename, resource_listdir
from public import public
@public
def find_name(dotted_name):
"""Import and return the named object in package space.
:param dotted_name: The dotted module path name to the object.
:type dotted_name: string
:return: The object.
:rtype: object
"""
package_path, dot, object_name = dotted_name.rpartition('.')
__import__(package_path)
return getattr(sys.modules[package_path], object_name)
@public
def call_name(dotted_name, *args, **kws):
"""Imports and calls the named object in package space.
:param dotted_name: The dotted module path name to the object.
:type dotted_name: string
:param args: The positional arguments.
:type args: tuple
:param kws: The keyword arguments.
:type kws: dict
:return: The object.
:rtype: object
"""
named_callable = find_name(dotted_name)
return named_callable(*args, **kws)
@public
def scan_module(module, interface):
"""Return all the items in a module that conform to an interface.
:param module: A module object. The module's `__all__` will be scanned.
:type module: module
:param interface: The interface that returned objects must conform to.
:type interface: `Interface`
:return: The sequence of matching components.
:rtype: objects implementing `interface`
"""
missing = object()
for name in module.__all__:
component = getattr(module, name, missing)
assert component is not missing, (
'%s has bad __all__: %s' % (module, name)) # pragma: no cover
if interface.implementedBy(component):
yield component
@public
def find_components(package, interface):
"""Find components which conform to a given interface.
Search all the modules in a given package, returning an iterator over all
objects found that conform to the given interface.
:param package: The package path to search.
:type package: string
:param interface: The interface that returned objects must conform to.
:type interface: `Interface`
:return: The sequence of matching components.
:rtype: objects implementing `interface`
"""
for filename in resource_listdir(package, ''):
basename, extension = os.path.splitext(filename)
if extension != '.py' or basename.startswith('.'):
continue
module_name = '{}.{}'.format(package, basename)
__import__(module_name, fromlist='*')
module = sys.modules[module_name]
if not hasattr(module, '__all__'):
continue
yield from scan_module(module, interface)
@public
def expand_path(url):
"""Expand a python: path, returning the absolute file system path."""
# Is the context coming from a file system or Python path?
if url.startswith('python:'):
resource_path = url[7:]
package, dot, resource = resource_path.rpartition('.')
return resource_filename(package, resource + '.cfg')
else:
return url
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