5c84ddad84
The __qualname__ attribute simplifies the determination of an objects class name and callable name and is useful in python 3.x to be able to use since it can correctly identify names better than the python 2.x __name__ attribute can. Adds a few tests in to ensure that the usage of __qualname__ where available functions as expected. See: http://legacy.python.org/dev/peps/pep-3155/ Fixes bug 1341441 Change-Id: Ic6942cbbc8e35d65fb3ac603ff1dfc8e20c194a3
253 lines
8.5 KiB
Python
253 lines
8.5 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2012-2013 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import inspect
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import types
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import six
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from taskflow.openstack.common import importutils
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try:
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_TYPE_TYPE = types.TypeType
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except AttributeError:
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_TYPE_TYPE = type
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# See: https://docs.python.org/2/library/__builtin__.html#module-__builtin__
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# and see https://docs.python.org/2/reference/executionmodel.html (and likely
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# others)...
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_BUILTIN_MODULES = ('builtins', '__builtin__', 'exceptions')
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def _get_members(obj, exclude_hidden):
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"""Yields the members of an object, filtering by hidden/not hidden."""
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for (name, value) in inspect.getmembers(obj):
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if name.startswith("_") and exclude_hidden:
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continue
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yield (name, value)
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def find_subclasses(locations, base_cls, exclude_hidden=True):
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"""Finds subclass types in the given locations.
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This will examines the given locations for types which are subclasses of
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the base class type provided and returns the found subclasses (or fails
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with exceptions if this introspection can not be accomplished).
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If a string is provided as one of the locations it will be imported and
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examined if it is a subclass of the base class. If a module is given,
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all of its members will be examined for attributes which are subclasses of
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the base class. If a type itself is given it will be examined for being a
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subclass of the base class.
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"""
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derived = set()
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for item in locations:
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module = None
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if isinstance(item, six.string_types):
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try:
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pkg, cls = item.split(':')
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except ValueError:
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module = importutils.import_module(item)
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else:
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obj = importutils.import_class('%s.%s' % (pkg, cls))
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if not is_subclass(obj, base_cls):
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raise TypeError("Item %s is not a %s subclass" %
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(item, base_cls))
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derived.add(obj)
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elif isinstance(item, types.ModuleType):
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module = item
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elif is_subclass(item, base_cls):
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derived.add(item)
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else:
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raise TypeError("Item %s unexpected type: %s" %
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(item, type(item)))
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# If it's a module derive objects from it if we can.
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if module is not None:
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for (_name, obj) in _get_members(module, exclude_hidden):
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if is_subclass(obj, base_cls):
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derived.add(obj)
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return derived
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def get_member_names(obj, exclude_hidden=True):
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"""Get all the member names for a object."""
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return [name for (name, _obj) in _get_members(obj, exclude_hidden)]
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def get_class_name(obj, fully_qualified=True):
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"""Get class name for object.
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If object is a type, fully qualified name of the type is returned.
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Else, fully qualified name of the type of the object is returned.
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For builtin types, just name is returned.
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"""
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if not isinstance(obj, six.class_types):
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obj = type(obj)
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try:
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built_in = obj.__module__ in _BUILTIN_MODULES
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except AttributeError:
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pass
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else:
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if built_in:
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try:
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return obj.__qualname__
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except AttributeError:
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return obj.__name__
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pieces = []
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try:
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pieces.append(obj.__qualname__)
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except AttributeError:
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pieces.append(obj.__name__)
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if fully_qualified:
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try:
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pieces.insert(0, obj.__module__)
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except AttributeError:
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pass
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return '.'.join(pieces)
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def get_all_class_names(obj, up_to=object):
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"""Get class names of object parent classes.
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Iterate over all class names object is instance or subclass of,
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in order of method resolution (mro). If up_to parameter is provided,
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only name of classes that are sublcasses to that class are returned.
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"""
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if not isinstance(obj, six.class_types):
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obj = type(obj)
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for cls in obj.mro():
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if issubclass(cls, up_to):
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yield get_class_name(cls)
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def get_callable_name(function):
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"""Generate a name from callable.
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Tries to do the best to guess fully qualified callable name.
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"""
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method_self = get_method_self(function)
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if method_self is not None:
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# This is a bound method.
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if isinstance(method_self, six.class_types):
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# This is a bound class method.
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im_class = method_self
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else:
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im_class = type(method_self)
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try:
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parts = (im_class.__module__, function.__qualname__)
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except AttributeError:
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parts = (im_class.__module__, im_class.__name__, function.__name__)
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elif inspect.ismethod(function) or inspect.isfunction(function):
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# This could be a function, a static method, a unbound method...
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try:
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parts = (function.__module__, function.__qualname__)
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except AttributeError:
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if hasattr(function, 'im_class'):
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# This is a unbound method, which exists only in python 2.x
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im_class = function.im_class
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parts = (im_class.__module__,
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im_class.__name__, function.__name__)
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else:
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parts = (function.__module__, function.__name__)
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else:
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im_class = type(function)
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if im_class is _TYPE_TYPE:
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im_class = function
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try:
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parts = (im_class.__module__, im_class.__qualname__)
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except AttributeError:
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parts = (im_class.__module__, im_class.__name__)
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return '.'.join(parts)
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def get_method_self(method):
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if not inspect.ismethod(method):
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return None
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try:
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return six.get_method_self(method)
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except AttributeError:
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return None
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def is_same_callback(callback1, callback2, strict=True):
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"""Returns if the two callbacks are the same."""
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if callback1 is callback2:
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# This happens when plain methods are given (or static/non-bound
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# methods).
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return True
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if callback1 == callback2:
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if not strict:
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return True
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# Two bound methods are equal if functions themselves are equal and
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# objects they are applied to are equal. This means that a bound
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# method could be the same bound method on another object if the
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# objects have __eq__ methods that return true (when in fact it is a
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# different bound method). Python u so crazy!
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try:
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self1 = six.get_method_self(callback1)
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self2 = six.get_method_self(callback2)
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return self1 is self2
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except AttributeError:
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pass
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return False
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def is_bound_method(method):
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"""Returns if the given method is bound to an object."""
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return bool(get_method_self(method))
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def is_subclass(obj, cls):
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"""Returns if the object is class and it is subclass of a given class."""
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return inspect.isclass(obj) and issubclass(obj, cls)
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def _get_arg_spec(function):
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if isinstance(function, type):
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bound = True
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function = function.__init__
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elif isinstance(function, (types.FunctionType, types.MethodType)):
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bound = is_bound_method(function)
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function = getattr(function, '__wrapped__', function)
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else:
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function = function.__call__
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bound = is_bound_method(function)
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return inspect.getargspec(function), bound
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def get_callable_args(function, required_only=False):
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"""Get names of callable arguments.
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Special arguments (like *args and **kwargs) are not included into
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output.
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If required_only is True, optional arguments (with default values)
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are not included into output.
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"""
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argspec, bound = _get_arg_spec(function)
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f_args = argspec.args
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if required_only and argspec.defaults:
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f_args = f_args[:-len(argspec.defaults)]
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if bound:
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f_args = f_args[1:]
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return f_args
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def accepts_kwargs(function):
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"""Returns True if function accepts kwargs."""
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argspec, _bound = _get_arg_spec(function)
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return bool(argspec.keywords)
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