"""Astroid hooks for the Python 2 standard library.
Currently help understanding of :
* hashlib.md5 and hashlib.sha1
"""
import sys
from functools import partial
from textwrap import dedent
from astroid import (
MANAGER, AsStringRegexpPredicate,
UseInferenceDefault, inference_tip,
YES, InferenceError, register_module_extender)
from astroid import exceptions
from astroid import nodes
from astroid.builder import AstroidBuilder
PY3K = sys.version_info > (3, 0)
PY33 = sys.version_info >= (3, 3)
# general function
def infer_func_form(node, base_type, context=None, enum=False):
"""Specific inference function for namedtuple or Python 3 enum. """
def infer_first(node):
try:
value = next(node.infer(context=context))
if value is YES:
raise UseInferenceDefault()
else:
return value
except StopIteration:
raise InferenceError()
# node is a CallFunc node, class name as first argument and generated class
# attributes as second argument
if len(node.args) != 2:
# something weird here, go back to class implementation
raise UseInferenceDefault()
# namedtuple or enums list of attributes can be a list of strings or a
# whitespace-separate string
try:
name = infer_first(node.args[0]).value
names = infer_first(node.args[1])
try:
attributes = names.value.replace(',', ' ').split()
except AttributeError:
if not enum:
attributes = [infer_first(const).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]).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]).value
for const in names.elts
if isinstance(const, nodes.Tuple)]
else:
attributes = [infer_first(const).value
for const in names.elts]
else:
raise AttributeError
if not attributes:
raise AttributeError
except (AttributeError, exceptions.InferenceError) as exc:
raise UseInferenceDefault()
# we want to return a Class node instance with proper attributes set
class_node = nodes.Class(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
class_node.instance_attrs[attr] = [fake_node]
return class_node, name, attributes
# module specific transformation functions #####################################
def hashlib_transform():
template = '''
class %(name)s(object):
def __init__(self, value=''): pass
def digest(self):
return %(digest)s
def copy(self):
return self
def update(self, value): pass
def hexdigest(self):
return ''
@property
def name(self):
return %(name)r
@property
def block_size(self):
return 1
@property
def digest_size(self):
return 1
'''
algorithms = ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512')
classes = "".join(
template % {'name': hashfunc, 'digest': 'b""' if PY3K else '""'}
for hashfunc in algorithms)
return AstroidBuilder(MANAGER).string_build(classes)
def collections_transform():
return AstroidBuilder(MANAGER).string_build('''
class defaultdict(dict):
default_factory = None
def __missing__(self, key): pass
class deque(object):
maxlen = 0
def __init__(self, iterable=None, maxlen=None): pass
def append(self, x): pass
def appendleft(self, x): pass
def clear(self): pass
def count(self, x): return 0
def extend(self, iterable): pass
def extendleft(self, iterable): pass
def pop(self): pass
def popleft(self): pass
def remove(self, value): pass
def reverse(self): pass
def rotate(self, n): pass
def __iter__(self): return self
''')
def pkg_resources_transform():
return AstroidBuilder(MANAGER).string_build('''
def resource_exists(package_or_requirement, resource_name):
pass
def resource_isdir(package_or_requirement, resource_name):
pass
def resource_filename(package_or_requirement, resource_name):
pass
def resource_stream(package_or_requirement, resource_name):
pass
def resource_string(package_or_requirement, resource_name):
pass
def resource_listdir(package_or_requirement, resource_name):
pass
def extraction_error():
pass
def get_cache_path(archive_name, names=()):
pass
def postprocess(tempname, filename):
pass
def set_extraction_path(path):
pass
def cleanup_resources(force=False):
pass
''')
def subprocess_transform():
if PY3K:
communicate = (bytes('string', 'ascii'), bytes('string', 'ascii'))
init = """
def __init__(self, args, bufsize=0, executable=None,
stdin=None, stdout=None, stderr=None,
preexec_fn=None, close_fds=False, shell=False,
cwd=None, env=None, universal_newlines=False,
startupinfo=None, creationflags=0, restore_signals=True,
start_new_session=False, pass_fds=()):
pass
"""
else:
communicate = ('string', 'string')
init = """
def __init__(self, args, bufsize=0, executable=None,
stdin=None, stdout=None, stderr=None,
preexec_fn=None, close_fds=False, shell=False,
cwd=None, env=None, universal_newlines=False,
startupinfo=None, creationflags=0):
pass
"""
if PY33:
wait_signature = 'def wait(self, timeout=None)'
else:
wait_signature = 'def wait(self)'
return AstroidBuilder(MANAGER).string_build('''
class Popen(object):
returncode = pid = 0
stdin = stdout = stderr = file()
%(init)s
def communicate(self, input=None):
return %(communicate)r
%(wait_signature)s:
return self.returncode
def poll(self):
return self.returncode
def send_signal(self, signal):
pass
def terminate(self):
pass
def kill(self):
pass
''' % {'init': init,
'communicate': communicate,
'wait_signature': wait_signature})
# namedtuple support ###########################################################
def looks_like_namedtuple(node):
func = node.func
if type(func) is nodes.Getattr:
return func.attrname == 'namedtuple'
if type(func) is nodes.Name:
return func.name == 'namedtuple'
return False
def infer_named_tuple(node, context=None):
"""Specific inference function for namedtuple CallFunc node"""
class_node, name, attributes = infer_func_form(node, nodes.Tuple._proxied,
context=context)
fake = AstroidBuilder(MANAGER).string_build('''
class %(name)s(tuple):
_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, **kwds):
result = _self._make(map(kwds.pop, %(fields)r, _self))
if kwds:
raise ValueError('Got unexpected field names: %%r' %% list(kwds))
return result
''' % {'name': name, 'fields': attributes})
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']
# we use UseInferenceDefault, we can't be a generator so return an iterator
return iter([class_node])
def infer_enum(node, context=None):
""" Specific inference function for enum CallFunc node. """
enum_meta = nodes.Class("EnumMeta", 'docstring')
class_node = infer_func_form(node, enum_meta,
context=context, enum=True)[0]
return iter([class_node.instanciate_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.AssName)
for value in values):
continue
stmt = values[0].statement()
if isinstance(stmt.targets[0], nodes.Tuple):
targets = stmt.targets[0].itered()
else:
targets = stmt.targets
new_targets = []
for target in targets:
# Replace all the assignments with our mocked class.
classdef = dedent('''
class %(name)s(object):
@property
def value(self):
# Not the best return.
return None
@property
def name(self):
return %(name)r
''' % {'name': target.name})
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.instanciate_class())
node.locals[local] = new_targets
break
return node
MANAGER.register_transform(nodes.CallFunc, inference_tip(infer_named_tuple),
looks_like_namedtuple)
MANAGER.register_transform(nodes.CallFunc, inference_tip(infer_enum),
AsStringRegexpPredicate('Enum', 'func'))
MANAGER.register_transform(nodes.Class, infer_enum_class)
register_module_extender(MANAGER, 'hashlib', hashlib_transform)
register_module_extender(MANAGER, 'collections', collections_transform)
register_module_extender(MANAGER, 'pkg_resources', pkg_resources_transform)
register_module_extender(MANAGER, 'subprocess', subprocess_transform)
Codebase Browser
chromium