oslo.utils/oslo_utils/reflection.py
Joshua Harlow b7130e0a5e Allow access to reflection 'get_members'
This also adds some basic tests to ensure the get*members
functions continue to work as expected under basic situations.

Change-Id: Iad9821dca01839b3d9662a16be68225ce99c432c
2015-08-03 21:18:03 -07:00

211 lines
6.9 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2012-2013 Yahoo! 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.
import inspect
import types
import six
try:
_TYPE_TYPE = types.TypeType
except AttributeError:
_TYPE_TYPE = type
# See: https://docs.python.org/2/library/__builtin__.html#module-__builtin__
# and see https://docs.python.org/2/reference/executionmodel.html (and likely
# others)...
_BUILTIN_MODULES = ('builtins', '__builtin__', '__builtins__', 'exceptions')
def get_members(obj, exclude_hidden=True):
"""Yields the members of an object, filtering by hidden/not hidden."""
for (name, value) in inspect.getmembers(obj):
if name.startswith("_") and exclude_hidden:
continue
yield (name, value)
def get_member_names(obj, exclude_hidden=True):
"""Get all the member names for a object."""
return [name for (name, _obj) in
get_members(obj, exclude_hidden=exclude_hidden)]
def get_class_name(obj, fully_qualified=True):
"""Get class name for object.
If object is a type, fully qualified name of the type is returned.
Else, fully qualified name of the type of the object is returned.
For builtin types, just name is returned.
"""
if not isinstance(obj, six.class_types):
obj = type(obj)
try:
built_in = obj.__module__ in _BUILTIN_MODULES
except AttributeError:
pass
else:
if built_in:
try:
return obj.__qualname__
except AttributeError:
return obj.__name__
pieces = []
try:
pieces.append(obj.__qualname__)
except AttributeError:
pieces.append(obj.__name__)
if fully_qualified:
try:
pieces.insert(0, obj.__module__)
except AttributeError:
pass
return '.'.join(pieces)
def get_all_class_names(obj, up_to=object):
"""Get class names of object parent classes.
Iterate over all class names object is instance or subclass of,
in order of method resolution (mro). If up_to parameter is provided,
only name of classes that are sublcasses to that class are returned.
"""
if not isinstance(obj, six.class_types):
obj = type(obj)
for cls in obj.mro():
if issubclass(cls, up_to):
yield get_class_name(cls)
def get_callable_name(function):
"""Generate a name from callable.
Tries to do the best to guess fully qualified callable name.
"""
method_self = get_method_self(function)
if method_self is not None:
# This is a bound method.
if isinstance(method_self, six.class_types):
# This is a bound class method.
im_class = method_self
else:
im_class = type(method_self)
try:
parts = (im_class.__module__, function.__qualname__)
except AttributeError:
parts = (im_class.__module__, im_class.__name__, function.__name__)
elif inspect.ismethod(function) or inspect.isfunction(function):
# This could be a function, a static method, a unbound method...
try:
parts = (function.__module__, function.__qualname__)
except AttributeError:
if hasattr(function, 'im_class'):
# This is a unbound method, which exists only in python 2.x
im_class = function.im_class
parts = (im_class.__module__,
im_class.__name__, function.__name__)
else:
parts = (function.__module__, function.__name__)
else:
im_class = type(function)
if im_class is _TYPE_TYPE:
im_class = function
try:
parts = (im_class.__module__, im_class.__qualname__)
except AttributeError:
parts = (im_class.__module__, im_class.__name__)
return '.'.join(parts)
def get_method_self(method):
"""Gets the ``self`` object attached to this method (or none)."""
if not inspect.ismethod(method):
return None
try:
return six.get_method_self(method)
except AttributeError:
return None
def is_same_callback(callback1, callback2, strict=True):
"""Returns if the two callbacks are the same."""
if callback1 is callback2:
# This happens when plain methods are given (or static/non-bound
# methods).
return True
if callback1 == callback2:
if not strict:
return True
# Two bound methods are equal if functions themselves are equal and
# objects they are applied to are equal. This means that a bound
# method could be the same bound method on another object if the
# objects have __eq__ methods that return true (when in fact it is a
# different bound method). Python u so crazy!
try:
self1 = six.get_method_self(callback1)
self2 = six.get_method_self(callback2)
return self1 is self2
except AttributeError:
pass
return False
def is_bound_method(method):
"""Returns if the given method is bound to an object."""
return bool(get_method_self(method))
def is_subclass(obj, cls):
"""Returns if the object is class and it is subclass of a given class."""
return inspect.isclass(obj) and issubclass(obj, cls)
def _get_arg_spec(function):
if isinstance(function, _TYPE_TYPE):
bound = True
function = function.__init__
elif isinstance(function, (types.FunctionType, types.MethodType)):
bound = is_bound_method(function)
function = getattr(function, '__wrapped__', function)
else:
function = function.__call__
bound = is_bound_method(function)
return inspect.getargspec(function), bound
def get_callable_args(function, required_only=False):
"""Get names of callable arguments.
Special arguments (like ``*args`` and ``**kwargs``) are not included into
output.
If required_only is True, optional arguments (with default values)
are not included into output.
"""
argspec, bound = _get_arg_spec(function)
f_args = argspec.args
if required_only and argspec.defaults:
f_args = f_args[:-len(argspec.defaults)]
if bound:
f_args = f_args[1:]
return f_args
def accepts_kwargs(function):
"""Returns True if function accepts kwargs."""
argspec, _bound = _get_arg_spec(function)
return bool(argspec.keywords)