239 lines
8.5 KiB
Python
239 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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"""
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Reflection module.
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.. versionadded:: 1.1
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"""
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import inspect
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import logging
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import operator
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import types
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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__', '__builtins__', 'exceptions')
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LOG = logging.getLogger(__name__)
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Parameter = inspect.Parameter
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Signature = inspect.Signature
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get_signature = inspect.signature
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def get_members(obj, exclude_hidden=True):
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"""Yields the members of an object, filtering by hidden/not hidden.
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.. versionadded:: 2.3
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"""
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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 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
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get_members(obj, exclude_hidden=exclude_hidden)]
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def get_class_name(obj, fully_qualified=True, truncate_builtins=True):
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"""Get class name for object.
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If object is a type, returns name of the type. If object is a bound
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method or a class method, returns its ``self`` object's class name.
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If object is an instance of class, returns instance's class name.
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Else, name of the type of the object is returned. If fully_qualified
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is True, returns fully qualified name of the type. For builtin types,
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just name is returned. TypeError is raised if can't get class name from
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object.
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"""
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if inspect.isfunction(obj):
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raise TypeError("Can't get class name.")
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if inspect.ismethod(obj):
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obj = get_method_self(obj)
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if not isinstance(obj, type):
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obj = type(obj)
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if truncate_builtins:
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try:
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built_in = obj.__module__ in _BUILTIN_MODULES
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except AttributeError: # nosec
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pass
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else:
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if built_in:
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return obj.__name__
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if fully_qualified and hasattr(obj, '__module__'):
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return '%s.%s' % (obj.__module__, obj.__name__)
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else:
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return obj.__name__
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def get_all_class_names(obj, up_to=object,
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fully_qualified=True, truncate_builtins=True):
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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, type):
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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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fully_qualified=fully_qualified,
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truncate_builtins=truncate_builtins)
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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, type):
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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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"""Gets the ``self`` object attached to this method (or none)."""
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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 operator.attrgetter("__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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'strict' arg has no meaning for python 3.8 onwards and will
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always return the equality of both callback based on 'self'
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comparison only.
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"""
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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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# NOTE(gmann): python3.8 onward, comparison of bound methods is
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# changed. It no longer decide the bound method's equality based
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# on their bounded objects equality instead it checks the identity
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# of their '__self__'. So python3.8 onward, two different bound
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# methods are no longer equal even __eq__ method return True.
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# Or in other term, 'strict' arg has no meaning from python 3.8
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# onwards above if condition never satisfy if both callback are
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# bounded to two different objects.
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# For backward compatibility for python <3.8, we can keep the 'strict'
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# arg and the below code of comparing 'self' and once minimum
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# supported python version is 3.8 we can remove both because python
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# 3.8 onward == operator itself checks identity of 'self'.
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# Ref bug: https://bugs.launchpad.net/oslo.utils/+bug/1841072
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if not strict:
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LOG.warning('"strict" arg is deprecated because it no '
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'longer work for python 3.8 onwards')
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return True
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# Until python 3.7, two bound methods are equal if functions
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# themselves are equal and objects they are applied to are equal.
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# This means that a bound method could be the same bound method on
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# another object if the objects have __eq__ methods that return true
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# (when in fact it is a different bound method). Python u so crazy!
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try:
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self1 = operator.attrgetter("__self__")(callback1)
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self2 = operator.attrgetter("__self__")(callback2)
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return self1 is self2
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except AttributeError: # nosec
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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 get_method_self(method) is not None
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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_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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sig = get_signature(function)
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function_args = list(iter(sig.parameters.keys()))
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for param_name, p in iter(sig.parameters.items()):
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if (p.kind in (Parameter.VAR_POSITIONAL, Parameter.VAR_KEYWORD) or
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(required_only and p.default is not Parameter.empty)):
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function_args.remove(param_name)
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return function_args
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def accepts_kwargs(function):
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"""Returns ``True`` if function accepts kwargs otherwise ``False``."""
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sig = get_signature(function)
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return any(p.kind == Parameter.VAR_KEYWORD
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for p in iter(sig.parameters.values()))
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