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# copyright 2003-2015 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of astroid.
#
# astroid is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 2.1 of the License, or (at your
# option) any later version.
#
# astroid is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
# for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with astroid. If not, see <http://www.gnu.org/licenses/>.
"""
Various helper utilities.
"""
import six
from astroid import bases
from astroid import exceptions
from astroid import manager
from astroid import raw_building
from astroid import scoped_nodes
BUILTINS = six.moves.builtins.__name__
def _build_proxy_class(cls_name, builtins):
proxy = raw_building.build_class(cls_name)
proxy.parent = builtins
return proxy
def _function_type(function, builtins):
if isinstance(function, scoped_nodes.Lambda):
if function.root().name == BUILTINS:
cls_name = 'builtin_function_or_method'
else:
cls_name = 'function'
elif isinstance(function, bases.BoundMethod):
if six.PY2:
cls_name = 'instancemethod'
else:
cls_name = 'method'
elif isinstance(function, bases.UnboundMethod):
if six.PY2:
cls_name = 'instancemethod'
else:
cls_name = 'function'
return _build_proxy_class(cls_name, builtins)
def _object_type(node, context=None):
astroid_manager = manager.AstroidManager()
builtins = astroid_manager.astroid_cache[BUILTINS]
context = context or bases.InferenceContext()
for inferred in node.infer(context=context):
if isinstance(inferred, scoped_nodes.Class):
if inferred.newstyle:
metaclass = inferred.metaclass()
if metaclass:
yield metaclass
continue
yield builtins.getattr('type')[0]
elif isinstance(inferred, (scoped_nodes.Lambda, bases.UnboundMethod)):
yield _function_type(inferred, builtins)
elif isinstance(inferred, scoped_nodes.Module):
yield _build_proxy_class('module', builtins)
else:
yield inferred._proxied
def object_type(node, context=None):
"""Obtain the type of the given node
The node will be inferred first, so this function can support all
sorts of objects, as long as they support inference. It will try to
retrieve the Python type, as returned by the builtin `type`.
"""
try:
types = set(_object_type(node, context))
except exceptions.InferenceError:
return bases.YES
if len(types) > 1 or not types:
return bases.YES
return list(types)[0]
def safe_infer(node, context=None):
"""Return the inferred value for the given node.
Return None if inference failed or if there is some ambiguity (more than
one node has been inferred).
"""
try:
inferit = node.infer(context=context)
value = next(inferit)
except exceptions.InferenceError:
return
try:
next(inferit)
return # None if there is ambiguity on the inferred node
except exceptions.InferenceError:
return # there is some kind of ambiguity
except StopIteration:
return value
def has_known_bases(klass, context=None):
"""Return true if all base classes of a class could be inferred."""
try:
return klass._all_bases_known
except AttributeError:
pass
for base in klass.bases:
result = safe_infer(base, context=context)
# TODO: check for A->B->A->B pattern in class structure too?
if (not isinstance(result, scoped_nodes.Class) or
result is klass or
not has_known_bases(result, context=context)):
klass._all_bases_known = False
return False
klass._all_bases_known = True
return True
def _type_check(type1, type2):
if not all(map(has_known_bases, (type1, type2))):
return bases.YES
if not all([type1.newstyle, type2.newstyle]):
return False
try:
return type1 in type2.mro()[:-1]
except exceptions.MroError:
# The MRO is invalid.
return bases.YES
def is_subtype(type1, type2):
"""Check if *type1* is a subtype of *typ2*."""
return _type_check(type2, type1)
def is_supertype(type1, type2):
"""Check if *type2* is a supertype of *type1*."""
return _type_check(type1, type2)
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