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# -*- test-case-name: twext.who.test.test_util -*-
##
# Copyright (c) 2013-2016 Apple Inc. All rights reserved.
#
# 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.
##
"""
Directory service module utilities.
"""
__all__ = [
"ConstantsContainer",
"uniqueResult",
"describe",
]
from inspect import getmembers, isclass, isfunction
from twisted.python.constants import (
Names, Values, Flags, NamedConstant, ValueConstant, FlagConstant,
)
from .idirectory import DirectoryServiceError
class ConstantsContainer(object):
"""
A container for constants.
"""
def __init__(self, sources):
self._constants = {}
self._methods = {}
for source in sources:
if isclass(source):
if issubclass(source, CONTAINER_CLASSES):
self._addConstants(source.iterconstants())
self._addMethods(getmembers(source, isfunction))
else:
raise TypeError(
"Unknown constants type: {0}".format(source)
)
elif isinstance(source, ConstantsContainer):
self._addConstants(source.iterconstants())
self._addMethods(source._methods.iteritems())
elif isinstance(source, CONSTANT_CLASSES):
self._addConstants((source,))
else:
self._addConstants(source)
def _addConstants(self, constants):
for constant in constants:
if hasattr(self, "_constantsClass"):
if constant.__class__ != self._constantsClass:
raise TypeError(
"Can't mix constants classes in the "
"same constants container: {0} != {1}"
.format(constant.__class__, self._constantsClass)
)
else:
self._constantsClass = constant.__class__
if issubclass(self._constantsClass, ValueConstant):
self.lookupByValue = self._lookupByValue
if (
constant.name in self._constants and
self._constants[constant.name] is not constant
):
raise ValueError("Name conflict: {0}".format(constant.name))
self._constants[constant.name] = constant
def _addMethods(self, methods):
for name, method in methods:
if name[0] == "_":
continue
if (
name in self._constants or
(name in self._methods and self._methods[name] is not method)
):
raise ValueError("Name conflict: {0}".format(name))
self._methods[name] = method
def __getattr__(self, name):
attr = self._constants.get(name, None)
if attr is not None:
return attr
attr = self._methods.get(name, None)
if attr is not None:
return attr
raise AttributeError(name)
def iterconstants(self):
return self._constants.itervalues()
def lookupByName(self, name):
try:
return self._constants[name]
except KeyError:
raise ValueError(name)
def _lookupByValue(self, value):
for constant in self.iterconstants():
if constant.value == value:
return constant
raise ValueError(value)
def uniqueResult(values):
result = None
for value in values:
if result is None:
result = value
else:
raise DirectoryServiceError(
"Multiple values found where one expected."
)
return result
def firstResult(values):
for value in values:
return value
return None
def describe(constant):
if isinstance(constant, FlagConstant):
return "|".join(
sorted(getattr(flag, "description", flag.name) for flag in constant)
)
if isinstance(constant, (NamedConstant, ValueConstant)):
for attr in ("description", "name"):
description = getattr(constant, attr, None)
if description is not None:
return description
return unicode(constant)
CONTAINER_CLASSES = (Names, Values, Flags)
CONSTANT_CLASSES = (NamedConstant, ValueConstant, FlagConstant)
|
