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# pylint: disable=W0611
#
# Copyright (c) 2003-2010 LOGILAB S.A. (Paris, FRANCE).
# http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
"""some functions that may be useful for various checkers
"""
from logilab import astng
from logilab.common.compat import builtins
BUILTINS_NAME = builtins.__name__
try:
# python >= 2.4
COMP_NODE_TYPES = (astng.ListComp, astng.SetComp, astng.DictComp,
astng.GenExpr)
except AttributeError:
COMP_NODE_TYPES = astng.ListComp
def safe_infer(node):
"""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()
value = inferit.next()
except astng.InferenceError:
return
try:
inferit.next()
return # None if there is ambiguity on the inferred node
except StopIteration:
return value
def is_super(node):
"""return True if the node is referencing the "super" builtin function
"""
if getattr(node, 'name', None) == 'super' and \
node.root().name == BUILTINS_NAME:
return True
return False
def is_error(node):
"""return true if the function does nothing but raising an exception"""
for child_node in node.get_children():
if isinstance(child_node, astng.Raise):
return True
return False
def is_raising(body):
"""return true if the given statement node raise an exception"""
for node in body:
if isinstance(node, astng.Raise):
return True
return False
def is_empty(body):
"""return true if the given node does nothing but 'pass'"""
return len(body) == 1 and isinstance(body[0], astng.Pass)
builtins = __builtins__.copy()
SPECIAL_BUILTINS = ('__builtins__',) # '__path__', '__file__')
def is_builtin(name): # was is_native_builtin
"""return true if <name> could be considered as a builtin defined by python
"""
if name in builtins:
return True
if name in SPECIAL_BUILTINS:
return True
return False
def is_defined_before(var_node):
"""return True if the variable node is defined by a parent node (list,
set, dict, or generator comprehension, lambda) or in a previous sibling
node on the same line (statement_defining ; statement_using)
"""
varname = var_node.name
_node = var_node.parent
while _node:
if isinstance(_node, COMP_NODE_TYPES):
for ass_node in _node.nodes_of_class(astng.AssName):
if ass_node.name == varname:
return True
elif isinstance(_node, astng.For):
for ass_node in _node.target.nodes_of_class(astng.AssName):
if ass_node.name == varname:
return True
elif isinstance(_node, astng.With):
if _node.vars is None:
# quickfix : case in which 'with' is used without 'as'
return False
if _node.vars.name == varname:
return True
elif isinstance(_node, (astng.Lambda, astng.Function)):
if _node.args.is_argument(varname):
return True
if getattr(_node, 'name', None) == varname:
return True
break
_node = _node.parent
# possibly multiple statements on the same line using semi colon separator
stmt = var_node.statement()
_node = stmt.previous_sibling()
lineno = stmt.fromlineno
while _node and _node.fromlineno == lineno:
for ass_node in _node.nodes_of_class(astng.AssName):
if ass_node.name == varname:
return True
for imp_node in _node.nodes_of_class( (astng.From, astng.Import)):
if varname in [name[1] or name[0] for name in imp_node.names]:
return True
_node = _node.previous_sibling()
return False
def is_func_default(node):
"""return true if the given Name node is used in function default argument's
value
"""
parent = node.scope()
if isinstance(parent, astng.Function):
for default_node in parent.args.defaults:
for default_name_node in default_node.nodes_of_class(astng.Name):
if default_name_node is node:
return True
return False
def is_func_decorator(node):
"""return true if the name is used in function decorator"""
parent = node.parent
while parent is not None:
if isinstance(parent, astng.Decorators):
return True
if parent.is_statement or isinstance(parent, astng.Lambda):
break
parent = parent.parent
return False
def is_ancestor_name(frame, node):
"""return True if `frame` is a astng.Class node with `node` in the
subtree of its bases attribute
"""
try:
bases = frame.bases
except AttributeError:
return False
for base in bases:
if node in base.nodes_of_class(astng.Name):
return True
return False
def assign_parent(node):
"""return the higher parent which is not an AssName, Tuple or List node
"""
while node and isinstance(node, (astng.AssName,
astng.Tuple,
astng.List)):
node = node.parent
return node
def overrides_an_abstract_method(class_node, name):
"""return True if pnode is a parent of node"""
for ancestor in class_node.ancestors():
if name in ancestor and isinstance(ancestor[name], astng.Function) and \
ancestor[name].is_abstract(pass_is_abstract=False):
return True
return False
def overrides_a_method(class_node, name):
"""return True if <name> is a method overridden from an ancestor"""
for ancestor in class_node.ancestors():
if name in ancestor and isinstance(ancestor[name], astng.Function):
return True
return False
PYMETHODS = set(('__new__', '__init__', '__del__', '__hash__',
'__str__', '__repr__',
'__len__', '__iter__',
'__delete__', '__get__', '__set__',
'__getitem__', '__setitem__', '__delitem__', '__contains__',
'__getattribute__', '__getattr__', '__setattr__', '__delattr__',
'__call__',
'__enter__', '__exit__',
'__cmp__', '__ge__', '__gt__', '__le__', '__lt__', '__eq__',
'__nonzero__', '__neg__', '__invert__',
'__mul__', '__imul__', '__rmul__',
'__div__', '__idiv__', '__rdiv__',
'__add__', '__iadd__', '__radd__',
'__sub__', '__isub__', '__rsub__',
'__pow__', '__ipow__', '__rpow__',
'__mod__', '__imod__', '__rmod__',
'__and__', '__iand__', '__rand__',
'__or__', '__ior__', '__ror__',
'__xor__', '__ixor__', '__rxor__',
# XXX To be continued
))
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