207 lines
7.0 KiB
Python
207 lines
7.0 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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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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"""Examines the given locations for types which are subclasses of the base
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class type provided and returns the found subclasses.
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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):
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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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if obj.__module__ in ('builtins', '__builtin__', 'exceptions'):
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return obj.__name__
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return '.'.join((obj.__module__, obj.__name__))
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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 bound method
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if isinstance(method_self, six.class_types):
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# this is 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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parts = (im_class.__module__, im_class.__name__,
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function.__name__)
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elif inspect.isfunction(function) or inspect.ismethod(function):
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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:
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im_class = function
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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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