oslo.utils/oslo_utils/reflection.py

222 lines
7.5 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.
"""
Reflection module.
.. versionadded:: 1.1
"""
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')
if six.PY3:
Parameter = inspect.Parameter
Signature = inspect.Signature
get_signature = inspect.signature
else:
# Provide an equivalent but use funcsigs instead...
import funcsigs
Parameter = funcsigs.Parameter
Signature = funcsigs.Signature
get_signature = funcsigs.signature
def get_members(obj, exclude_hidden=True):
"""Yields the members of an object, filtering by hidden/not hidden.
.. versionadded:: 2.3
"""
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, truncate_builtins=True):
"""Get class name for object.
If object is a type, returns name of the type. If object is a bound
method or a class method, returns its ``self`` object's class name.
If object is an instance of class, returns instance's class name.
Else, name of the type of the object is returned. If fully_qualified
is True, returns fully qualified name of the type. For builtin types,
just name is returned. TypeError is raised if can't get class name from
object.
"""
if inspect.isfunction(obj):
raise TypeError("Can't get class name.")
if inspect.ismethod(obj):
obj = get_method_self(obj)
if not isinstance(obj, six.class_types):
obj = type(obj)
if truncate_builtins:
try:
built_in = obj.__module__ in _BUILTIN_MODULES
except AttributeError: # nosec
pass
else:
if built_in:
return obj.__name__
if fully_qualified and hasattr(obj, '__module__'):
return '%s.%s' % (obj.__module__, obj.__name__)
else:
return obj.__name__
def get_all_class_names(obj, up_to=object,
fully_qualified=True, truncate_builtins=True):
"""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,
fully_qualified=fully_qualified,
truncate_builtins=truncate_builtins)
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: # nosec
pass
return False
def is_bound_method(method):
"""Returns if the given method is bound to an object."""
return get_method_self(method) is not None
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_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.
"""
sig = get_signature(function)
function_args = list(six.iterkeys(sig.parameters))
for param_name, p in six.iteritems(sig.parameters):
if (p.kind in (Parameter.VAR_POSITIONAL, Parameter.VAR_KEYWORD)
or (required_only and p.default is not Parameter.empty)):
function_args.remove(param_name)
return function_args
def accepts_kwargs(function):
"""Returns ``True`` if function accepts kwargs otherwise ``False``."""
sig = get_signature(function)
return any(p.kind == Parameter.VAR_KEYWORD
for p in six.itervalues(sig.parameters))