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- # Copyright (c) 2012-2015 LOGILAB S.A. (Paris, FRANCE) <contact@logilab.fr>
- # Copyright (c) 2014-2016 Claudiu Popa <pcmanticore@gmail.com>
-
- # Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
- # For details: https://github.com/PyCQA/astroid/blob/master/COPYING.LESSER
-
- """Astroid hooks for the Python standard library."""
-
- import functools
- import sys
- import keyword
- from textwrap import dedent
-
- from astroid import (
- MANAGER, UseInferenceDefault, inference_tip,
- InferenceError)
- from astroid import arguments
- from astroid import exceptions
- from astroid import nodes
- from astroid.builder import AstroidBuilder, extract_node
- from astroid import util
-
-
- def _infer_first(node, context):
- if node is util.Uninferable:
- raise UseInferenceDefault
- try:
- value = next(node.infer(context=context))
- if value is util.Uninferable:
- raise UseInferenceDefault()
- else:
- return value
- except StopIteration:
- raise InferenceError()
-
-
- def _find_func_form_arguments(node, context):
-
- def _extract_namedtuple_arg_or_keyword(position, key_name=None):
-
- if len(args) > position:
- return _infer_first(args[position], context)
- if key_name and key_name in found_keywords:
- return _infer_first(found_keywords[key_name], context)
-
- args = node.args
- keywords = node.keywords
- found_keywords = {
- keyword.arg: keyword.value for keyword in keywords
- } if keywords else {}
-
- name = _extract_namedtuple_arg_or_keyword(
- position=0,
- key_name='typename'
- )
- names = _extract_namedtuple_arg_or_keyword(
- position=1,
- key_name='field_names'
- )
- if name and names:
- return name.value, names
-
- raise UseInferenceDefault()
-
-
- def infer_func_form(node, base_type, context=None, enum=False):
- """Specific inference function for namedtuple or Python 3 enum. """
- # node is a Call node, class name as first argument and generated class
- # attributes as second argument
-
- # namedtuple or enums list of attributes can be a list of strings or a
- # whitespace-separate string
- try:
- name, names = _find_func_form_arguments(node, context)
- try:
- attributes = names.value.replace(',', ' ').split()
- except AttributeError:
- if not enum:
- attributes = [_infer_first(const, context).value
- for const in names.elts]
- else:
- # Enums supports either iterator of (name, value) pairs
- # or mappings.
- # TODO: support only list, tuples and mappings.
- if hasattr(names, 'items') and isinstance(names.items, list):
- attributes = [_infer_first(const[0], context).value
- for const in names.items
- if isinstance(const[0], nodes.Const)]
- elif hasattr(names, 'elts'):
- # Enums can support either ["a", "b", "c"]
- # or [("a", 1), ("b", 2), ...], but they can't
- # be mixed.
- if all(isinstance(const, nodes.Tuple)
- for const in names.elts):
- attributes = [_infer_first(const.elts[0], context).value
- for const in names.elts
- if isinstance(const, nodes.Tuple)]
- else:
- attributes = [_infer_first(const, context).value
- for const in names.elts]
- else:
- raise AttributeError
- if not attributes:
- raise AttributeError
- except (AttributeError, exceptions.InferenceError):
- raise UseInferenceDefault()
-
- # If we can't infer the name of the class, don't crash, up to this point
- # we know it is a namedtuple anyway.
- name = name or 'Uninferable'
- # we want to return a Class node instance with proper attributes set
- class_node = nodes.ClassDef(name, 'docstring')
- class_node.parent = node.parent
- # set base class=tuple
- class_node.bases.append(base_type)
- # XXX add __init__(*attributes) method
- for attr in attributes:
- fake_node = nodes.EmptyNode()
- fake_node.parent = class_node
- fake_node.attrname = attr
- class_node.instance_attrs[attr] = [fake_node]
- return class_node, name, attributes
-
-
- def _looks_like(node, name):
- func = node.func
- if isinstance(func, nodes.Attribute):
- return func.attrname == name
- if isinstance(func, nodes.Name):
- return func.name == name
- return False
-
- _looks_like_namedtuple = functools.partial(_looks_like, name='namedtuple')
- _looks_like_enum = functools.partial(_looks_like, name='Enum')
-
-
- def infer_named_tuple(node, context=None):
- """Specific inference function for namedtuple Call node"""
- class_node, name, attributes = infer_func_form(node, nodes.Tuple._proxied,
- context=context)
- call_site = arguments.CallSite.from_call(node)
- func = next(extract_node('import collections; collections.namedtuple').infer())
- try:
- rename = next(call_site.infer_argument(func, 'rename', context)).bool_value()
- except InferenceError:
- rename = False
-
- if rename:
- attributes = _get_renamed_namedtuple_atributes(attributes)
-
- replace_args = ', '.join(
- '{arg}=None'.format(arg=arg)
- for arg in attributes
- )
-
- field_def = (" {name} = property(lambda self: self[{index:d}], "
- "doc='Alias for field number {index:d}')")
- field_defs = '\n'.join(field_def.format(name=name, index=index)
- for index, name in enumerate(attributes))
- fake = AstroidBuilder(MANAGER).string_build('''
- class %(name)s(tuple):
- __slots__ = ()
- _fields = %(fields)r
- def _asdict(self):
- return self.__dict__
- @classmethod
- def _make(cls, iterable, new=tuple.__new__, len=len):
- return new(cls, iterable)
- def _replace(self, %(replace_args)s):
- return self
- def __getnewargs__(self):
- return tuple(self)
- %(field_defs)s
- ''' % {'name': name,
- 'fields': attributes,
- 'field_defs': field_defs,
- 'replace_args': replace_args})
- class_node.locals['_asdict'] = fake.body[0].locals['_asdict']
- class_node.locals['_make'] = fake.body[0].locals['_make']
- class_node.locals['_replace'] = fake.body[0].locals['_replace']
- class_node.locals['_fields'] = fake.body[0].locals['_fields']
- for attr in attributes:
- class_node.locals[attr] = fake.body[0].locals[attr]
- # we use UseInferenceDefault, we can't be a generator so return an iterator
- return iter([class_node])
-
-
- def _get_renamed_namedtuple_atributes(field_names):
- names = list(field_names)
- seen = set()
- for i, name in enumerate(field_names):
- if (not all(c.isalnum() or c == '_' for c in name) or keyword.iskeyword(name)
- or not name or name[0].isdigit() or name.startswith('_') or name in seen):
- names[i] = '_%d' % i
- seen.add(name)
- return tuple(names)
-
-
- def infer_enum(node, context=None):
- """ Specific inference function for enum Call node. """
- enum_meta = extract_node('''
- class EnumMeta(object):
- 'docstring'
- def __call__(self, node):
- class EnumAttribute(object):
- name = ''
- value = 0
- return EnumAttribute()
- def __iter__(self):
- class EnumAttribute(object):
- name = ''
- value = 0
- return [EnumAttribute()]
- def __next__(self):
- return next(iter(self))
- def __getitem__(self, attr):
- class Value(object):
- @property
- def name(self):
- return ''
- @property
- def value(self):
- return attr
-
- return Value()
- __members__ = ['']
- ''')
- class_node = infer_func_form(node, enum_meta,
- context=context, enum=True)[0]
- return iter([class_node.instantiate_class()])
-
-
- def infer_enum_class(node):
- """ Specific inference for enums. """
- names = set(('Enum', 'IntEnum', 'enum.Enum', 'enum.IntEnum'))
- for basename in node.basenames:
- # TODO: doesn't handle subclasses yet. This implementation
- # is a hack to support enums.
- if basename not in names:
- continue
- if node.root().name == 'enum':
- # Skip if the class is directly from enum module.
- break
- for local, values in node.locals.items():
- if any(not isinstance(value, nodes.AssignName)
- for value in values):
- continue
-
- stmt = values[0].statement()
- if isinstance(stmt, nodes.Assign):
- if isinstance(stmt.targets[0], nodes.Tuple):
- targets = stmt.targets[0].itered()
- else:
- targets = stmt.targets
- elif isinstance(stmt, nodes.AnnAssign):
- targets = [stmt.target]
-
- new_targets = []
- for target in targets:
- # Replace all the assignments with our mocked class.
- classdef = dedent('''
- class %(name)s(%(types)s):
- @property
- def value(self):
- # Not the best return.
- return None
- @property
- def name(self):
- return %(name)r
- ''' % {'name': target.name, 'types': ', '.join(node.basenames)})
- fake = AstroidBuilder(MANAGER).string_build(classdef)[target.name]
- fake.parent = target.parent
- for method in node.mymethods():
- fake.locals[method.name] = [method]
- new_targets.append(fake.instantiate_class())
- node.locals[local] = new_targets
- break
- return node
-
-
- MANAGER.register_transform(nodes.Call, inference_tip(infer_named_tuple),
- _looks_like_namedtuple)
- MANAGER.register_transform(nodes.Call, inference_tip(infer_enum),
- _looks_like_enum)
- MANAGER.register_transform(nodes.ClassDef, infer_enum_class)
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