/tools/logilab/astng/inference.py
Python | 382 lines | 321 code | 12 blank | 49 comment | 34 complexity | 4754814394e22e695839d521670b970b MD5 | raw file
- # copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
- # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
- # copyright 2003-2010 Sylvain Thenault, all rights reserved.
- # contact mailto:thenault@gmail.com
- #
- # This file is part of logilab-astng.
- #
- # logilab-astng 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.
- #
- # logilab-astng 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 logilab-astng. If not, see <http://www.gnu.org/licenses/>.
- """this module contains a set of functions to handle inference on astng trees
- """
- __doctype__ = "restructuredtext en"
- from itertools import chain
- import sys
- from logilab.astng import nodes
- from logilab.astng.manager import ASTNGManager
- from logilab.astng.exceptions import (ASTNGBuildingException, ASTNGError,
- InferenceError, NoDefault, NotFoundError, UnresolvableName)
- from logilab.astng.bases import YES, Instance, InferenceContext, Generator, \
- _infer_stmts, copy_context, path_wrapper, raise_if_nothing_infered
- from logilab.astng.protocols import _arguments_infer_argname
- MANAGER = ASTNGManager()
- class CallContext:
- """when inferring a function call, this class is used to remember values
- given as argument
- """
- def __init__(self, args, starargs, dstarargs):
- self.args = []
- self.nargs = {}
- for arg in args:
- if isinstance(arg, nodes.Keyword):
- self.nargs[arg.arg] = arg.value
- else:
- self.args.append(arg)
- self.starargs = starargs
- self.dstarargs = dstarargs
- def infer_argument(self, funcnode, name, context):
- """infer a function argument value according to the call context"""
- # 1. search in named keywords
- try:
- return self.nargs[name].infer(context)
- except KeyError:
- # Function.args.args can be None in astng (means that we don't have
- # information on argnames)
- argindex = funcnode.args.find_argname(name)[0]
- if argindex is not None:
- # 2. first argument of instance/class method
- if argindex == 0 and funcnode.type in ('method', 'classmethod'):
- if context.boundnode is not None:
- boundnode = context.boundnode
- else:
- # XXX can do better ?
- boundnode = funcnode.parent.frame()
- if funcnode.type == 'method':
- if not isinstance(boundnode, Instance):
- boundnode = Instance(boundnode)
- return iter((boundnode,))
- if funcnode.type == 'classmethod':
- return iter((boundnode,))
- # 2. search arg index
- try:
- return self.args[argindex].infer(context)
- except IndexError:
- pass
- # 3. search in *args (.starargs)
- if self.starargs is not None:
- its = []
- for infered in self.starargs.infer(context):
- if infered is YES:
- its.append((YES,))
- continue
- try:
- its.append(infered.getitem(argindex, context).infer(context))
- except (InferenceError, AttributeError):
- its.append((YES,))
- except (IndexError, TypeError):
- continue
- if its:
- return chain(*its)
- # 4. XXX search in **kwargs (.dstarargs)
- if self.dstarargs is not None:
- its = []
- for infered in self.dstarargs.infer(context):
- if infered is YES:
- its.append((YES,))
- continue
- try:
- its.append(infered.getitem(name, context).infer(context))
- except (InferenceError, AttributeError):
- its.append((YES,))
- except (IndexError, TypeError):
- continue
- if its:
- return chain(*its)
- # 5. */** argument, (Tuple or Dict)
- if name == funcnode.args.vararg:
- return iter((nodes.const_factory(())))
- if name == funcnode.args.kwarg:
- return iter((nodes.const_factory({})))
- # 6. return default value if any
- try:
- return funcnode.args.default_value(name).infer(context)
- except NoDefault:
- raise InferenceError(name)
- # .infer method ###############################################################
- def infer_end(self, context=None):
- """inference's end for node such as Module, Class, Function, Const...
- """
- yield self
- nodes.Module.infer = infer_end
- nodes.Class.infer = infer_end
- nodes.Function.infer = infer_end
- nodes.Lambda.infer = infer_end
- nodes.Const.infer = infer_end
- nodes.List.infer = infer_end
- nodes.Tuple.infer = infer_end
- nodes.Dict.infer = infer_end
- def infer_name(self, context=None):
- """infer a Name: use name lookup rules"""
- frame, stmts = self.lookup(self.name)
- if not stmts:
- raise UnresolvableName(self.name)
- context = context.clone()
- context.lookupname = self.name
- return _infer_stmts(stmts, context, frame)
- nodes.Name.infer = path_wrapper(infer_name)
- nodes.AssName.infer_lhs = infer_name # won't work with a path wrapper
- def infer_callfunc(self, context=None):
- """infer a CallFunc node by trying to guess what the function returns"""
- callcontext = context.clone()
- callcontext.callcontext = CallContext(self.args, self.starargs, self.kwargs)
- callcontext.boundnode = None
- for callee in self.func.infer(context):
- if callee is YES:
- yield callee
- continue
- try:
- if hasattr(callee, 'infer_call_result'):
- for infered in callee.infer_call_result(self, callcontext):
- yield infered
- except InferenceError:
- ## XXX log error ?
- continue
- nodes.CallFunc.infer = path_wrapper(raise_if_nothing_infered(infer_callfunc))
- def infer_import(self, context=None, asname=True):
- """infer an Import node: return the imported module/object"""
- name = context.lookupname
- if name is None:
- raise InferenceError()
- if asname:
- yield self.do_import_module(self.real_name(name))
- else:
- yield self.do_import_module(name)
- nodes.Import.infer = path_wrapper(infer_import)
- def infer_name_module(self, name):
- context = InferenceContext()
- context.lookupname = name
- return self.infer(context, asname=False)
- nodes.Import.infer_name_module = infer_name_module
- def infer_from(self, context=None, asname=True):
- """infer a From nodes: return the imported module/object"""
- name = context.lookupname
- if name is None:
- raise InferenceError()
- if asname:
- name = self.real_name(name)
- module = self.do_import_module(self.modname)
- try:
- context = copy_context(context)
- context.lookupname = name
- return _infer_stmts(module.getattr(name, ignore_locals=module is self.root()), context)
- except NotFoundError:
- raise InferenceError(name)
- nodes.From.infer = path_wrapper(infer_from)
- def infer_getattr(self, context=None):
- """infer a Getattr node by using getattr on the associated object"""
- #context = context.clone()
- for owner in self.expr.infer(context):
- if owner is YES:
- yield owner
- continue
- try:
- context.boundnode = owner
- for obj in owner.igetattr(self.attrname, context):
- yield obj
- context.boundnode = None
- except (NotFoundError, InferenceError):
- context.boundnode = None
- except AttributeError:
- # XXX method / function
- context.boundnode = None
- nodes.Getattr.infer = path_wrapper(raise_if_nothing_infered(infer_getattr))
- nodes.AssAttr.infer_lhs = raise_if_nothing_infered(infer_getattr) # # won't work with a path wrapper
- def infer_global(self, context=None):
- if context.lookupname is None:
- raise InferenceError()
- try:
- return _infer_stmts(self.root().getattr(context.lookupname), context)
- except NotFoundError:
- raise InferenceError()
- nodes.Global.infer = path_wrapper(infer_global)
- def infer_subscript(self, context=None):
- """infer simple subscription such as [1,2,3][0] or (1,2,3)[-1]"""
- if isinstance(self.slice, nodes.Index):
- index = self.slice.value.infer(context).next()
- if index is YES:
- yield YES
- return
- try:
- # suppose it's a Tuple/List node (attribute error else)
- assigned = self.value.getitem(index.value, context)
- except AttributeError:
- raise InferenceError()
- except (IndexError, TypeError):
- yield YES
- return
- for infered in assigned.infer(context):
- yield infered
- else:
- raise InferenceError()
- nodes.Subscript.infer = path_wrapper(infer_subscript)
- nodes.Subscript.infer_lhs = raise_if_nothing_infered(infer_subscript)
- UNARY_OP_METHOD = {'+': '__pos__',
- '-': '__neg__',
- '~': '__invert__',
- 'not': None, # XXX not '__nonzero__'
- }
- def infer_unaryop(self, context=None):
- for operand in self.operand.infer(context):
- try:
- yield operand.infer_unary_op(self.op)
- except TypeError:
- continue
- except AttributeError:
- meth = UNARY_OP_METHOD[self.op]
- if meth is None:
- yield YES
- else:
- try:
- # XXX just suppose if the type implement meth, returned type
- # will be the same
- operand.getattr(meth)
- yield operand
- except GeneratorExit:
- raise
- except:
- yield YES
- nodes.UnaryOp.infer = path_wrapper(infer_unaryop)
- BIN_OP_METHOD = {'+': '__add__',
- '-': '__sub__',
- '/': '__div__',
- '//': '__floordiv__',
- '*': '__mul__',
- '**': '__power__',
- '%': '__mod__',
- '&': '__and__',
- '|': '__or__',
- '^': '__xor__',
- '<<': '__lshift__',
- '>>': '__rshift__',
- }
- def _infer_binop(operator, operand1, operand2, context, failures=None):
- if operand1 is YES:
- yield operand1
- return
- try:
- for valnode in operand1.infer_binary_op(operator, operand2, context):
- yield valnode
- except AttributeError:
- try:
- # XXX just suppose if the type implement meth, returned type
- # will be the same
- operand1.getattr(BIN_OP_METHOD[operator])
- yield operand1
- except:
- if failures is None:
- yield YES
- else:
- failures.append(operand1)
- def infer_binop(self, context=None):
- failures = []
- for lhs in self.left.infer(context):
- for val in _infer_binop(self.op, lhs, self.right, context, failures):
- yield val
- for lhs in failures:
- for rhs in self.right.infer(context):
- for val in _infer_binop(self.op, rhs, lhs, context):
- yield val
- nodes.BinOp.infer = path_wrapper(infer_binop)
- def infer_arguments(self, context=None):
- name = context.lookupname
- if name is None:
- raise InferenceError()
- return _arguments_infer_argname(self, name, context)
- nodes.Arguments.infer = infer_arguments
- def infer_ass(self, context=None):
- """infer a AssName/AssAttr: need to inspect the RHS part of the
- assign node
- """
- stmt = self.statement()
- if isinstance(stmt, nodes.AugAssign):
- return stmt.infer(context)
- stmts = list(self.assigned_stmts(context=context))
- return _infer_stmts(stmts, context)
- nodes.AssName.infer = path_wrapper(infer_ass)
- nodes.AssAttr.infer = path_wrapper(infer_ass)
- def infer_augassign(self, context=None):
- failures = []
- for lhs in self.target.infer_lhs(context):
- for val in _infer_binop(self.op, lhs, self.value, context, failures):
- yield val
- for lhs in failures:
- for rhs in self.value.infer(context):
- for val in _infer_binop(self.op, rhs, lhs, context):
- yield val
- nodes.AugAssign.infer = path_wrapper(infer_augassign)
- # no infer method on DelName and DelAttr (expected InferenceError)
- def infer_empty_node(self, context=None):
- if not self.has_underlying_object():
- yield YES
- else:
- try:
- for infered in MANAGER.infer_astng_from_something(self.object,
- context=context):
- yield infered
- except ASTNGError:
- yield YES
- nodes.EmptyNode.infer = path_wrapper(infer_empty_node)