Add pylint to depot_tools.

third_party/logilab/astng/protocols.py

+# 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 python protocols for nodes
+where it makes sense.
+"""
+
+__doctype__ = "restructuredtext en"
+
+from logilab.astng.exceptions import InferenceError, NoDefault
+from logilab.astng.node_classes import unpack_infer
+from logilab.astng.bases import copy_context, \
+     raise_if_nothing_infered, yes_if_nothing_infered, Instance, Generator, YES
+from logilab.astng.nodes import const_factory
+from logilab.astng import nodes
+
+# unary operations ############################################################
+
+def tl_infer_unary_op(self, operator):
+    if operator == 'not':
+        return const_factory(not bool(self.elts))
+    raise TypeError() # XXX log unsupported operation
+nodes.Tuple.infer_unary_op = tl_infer_unary_op
+nodes.List.infer_unary_op = tl_infer_unary_op
+
+
+def dict_infer_unary_op(self, operator):
+    if operator == 'not':
+        return const_factory(not bool(self.items))
+    raise TypeError() # XXX log unsupported operation
+nodes.Dict.infer_unary_op = dict_infer_unary_op
+
+
+def const_infer_unary_op(self, operator):
+    if operator == 'not':
+        return const_factory(not self.value)
+    # XXX log potentially raised TypeError
+    elif operator == '+':
+        return const_factory(+self.value)
+    else: # operator == '-':
+        return const_factory(-self.value)
+nodes.Const.infer_unary_op = const_infer_unary_op
+
+
+# binary operations ###########################################################
+
+BIN_OP_IMPL = {'+':  lambda a, b: a + b,
+               '-':  lambda a, b: a - b,
+               '/':  lambda a, b: a / b,
+               '//': lambda a, b: a // b,
+               '*':  lambda a, b: a * b,
+               '**': lambda a, b: a ** b,
+               '%':  lambda a, b: a % b,
+               '&':  lambda a, b: a & b,
+               '|':  lambda a, b: a | b,
+               '^':  lambda a, b: a ^ b,
+               '<<': lambda a, b: a << b,
+               '>>': lambda a, b: a >> b,
+               }
+for key, impl in BIN_OP_IMPL.items():
+    BIN_OP_IMPL[key+'='] = impl
+
+def const_infer_binary_op(self, operator, other, context):
+    for other in other.infer(context):
+        if isinstance(other, nodes.Const):
+            try:
+                impl = BIN_OP_IMPL[operator]
+
+                try:
+                    yield const_factory(impl(self.value, other.value))
+                except Exception:
+                    # ArithmeticError is not enough: float >> float is a TypeError
+                    # TODO : let pylint know about the problem
+                    pass
+            except TypeError:
+                # XXX log TypeError
+                continue
+        elif other is YES:
+            yield other
+        else:
+            try:
+                for val in other.infer_binary_op(operator, self, context):
+                    yield val
+            except AttributeError:
+                yield YES
+nodes.Const.infer_binary_op = yes_if_nothing_infered(const_infer_binary_op)
+
+
+def tl_infer_binary_op(self, operator, other, context):
+    for other in other.infer(context):
+        if isinstance(other, self.__class__) and operator == '+':
+            node = self.__class__()
+            elts = [n for elt in self.elts for n in elt.infer(context)
+                    if not n is YES]
+            elts += [n for elt in other.elts for n in elt.infer(context)
+                     if not n is YES]
+            node.elts = elts
+            yield node
+        elif isinstance(other, nodes.Const) and operator == '*':
+            if not isinstance(other.value, int):
+                yield YES
+                continue
+            node = self.__class__()
+            elts = [n for elt in self.elts for n in elt.infer(context)
+                    if not n is YES] * other.value
+            node.elts = elts
+            yield node
+        elif isinstance(other, Instance) and not isinstance(other, nodes.Const):
+            yield YES
+    # XXX else log TypeError
+nodes.Tuple.infer_binary_op = yes_if_nothing_infered(tl_infer_binary_op)
+nodes.List.infer_binary_op = yes_if_nothing_infered(tl_infer_binary_op)
+
+
+def dict_infer_binary_op(self, operator, other, context):
+    for other in other.infer(context):
+        if isinstance(other, Instance) and isinstance(other._proxied, nodes.Class):
+            yield YES
+        # XXX else log TypeError
+nodes.Dict.infer_binary_op = yes_if_nothing_infered(dict_infer_binary_op)
+
+
+# assignment ##################################################################
+
+"""the assigned_stmts method is responsible to return the assigned statement
+(e.g. not inferred) according to the assignment type.
+
+The `asspath` argument is used to record the lhs path of the original node.
+For instance if we want assigned statements for 'c' in 'a, (b,c)', asspath
+will be [1, 1] once arrived to the Assign node.
+
+The `context` argument is the current inference context which should be given
+to any intermediary inference necessary.
+"""
+
+def _resolve_looppart(parts, asspath, context):
+    """recursive function to resolve multiple assignments on loops"""
+    asspath = asspath[:]
+    index = asspath.pop(0)
+    for part in parts:
+        if part is YES:
+            continue
+        # XXX handle __iter__ and log potentially detected errors
+        if not hasattr(part, 'itered'):
+            continue
+        try:
+            itered = part.itered()
+        except TypeError:
+            continue # XXX log error
+        for stmt in itered:
+            try:
+                assigned = stmt.getitem(index, context)
+            except (AttributeError, IndexError):
+                continue
+            except TypeError, exc: # stmt is unsubscriptable Const
+                continue
+            if not asspath:
+                # we achieved to resolved the assignment path,
+                # don't infer the last part
+                yield assigned
+            elif assigned is YES:
+                break
+            else:
+                # we are not yet on the last part of the path
+                # search on each possibly inferred value
+                try:
+                    for infered in _resolve_looppart(assigned.infer(context),
+                                                     asspath, context):
+                        yield infered
+                except InferenceError:
+                    break
+
+
+def for_assigned_stmts(self, node, context=None, asspath=None):
+    if asspath is None:
+        for lst in self.iter.infer(context):
+            if isinstance(lst, (nodes.Tuple, nodes.List)):
+                for item in lst.elts:
+                    yield item
+    else:
+        for infered in _resolve_looppart(self.iter.infer(context),
+                                         asspath, context):
+            yield infered
+
+nodes.For.assigned_stmts = raise_if_nothing_infered(for_assigned_stmts)
+nodes.Comprehension.assigned_stmts = raise_if_nothing_infered(for_assigned_stmts)
+
+
+def mulass_assigned_stmts(self, node, context=None, asspath=None):
+    if asspath is None:
+        asspath = []
+    asspath.insert(0, self.elts.index(node))
+    return self.parent.assigned_stmts(self, context, asspath)
+nodes.Tuple.assigned_stmts = mulass_assigned_stmts
+nodes.List.assigned_stmts = mulass_assigned_stmts
+
+
+def assend_assigned_stmts(self, context=None):
+    return self.parent.assigned_stmts(self, context=context)
+nodes.AssName.assigned_stmts = assend_assigned_stmts
+nodes.AssAttr.assigned_stmts = assend_assigned_stmts
+
+
+def _arguments_infer_argname(self, name, context):
+    # arguments information may be missing, in which case we can't do anything
+    # more
+    if not (self.args or self.vararg or self.kwarg):
+        yield YES
+        return
+    # first argument of instance/class method
+    if self.args and getattr(self.args[0], 'name', None) == name:
+        functype = self.parent.type
+        if functype == 'method':
+            yield Instance(self.parent.parent.frame())
+            return
+        if functype == 'classmethod':
+            yield self.parent.parent.frame()
+            return
+    if name == self.vararg:
+        yield const_factory(())
+        return
+    if name == self.kwarg:
+        yield const_factory({})
+        return
+    # if there is a default value, yield it. And then yield YES to reflect
+    # we can't guess given argument value
+    try:
+        context = copy_context(context)
+        for infered in self.default_value(name).infer(context):
+            yield infered
+        yield YES
+    except NoDefault:
+        yield YES
+
+
+def arguments_assigned_stmts(self, node, context, asspath=None):
+    if context.callcontext:
+        # reset call context/name
+        callcontext = context.callcontext
+        context = copy_context(context)
+        context.callcontext = None
+        for infered in callcontext.infer_argument(self.parent, node.name, context):
+            yield infered
+        return
+    for infered in _arguments_infer_argname(self, node.name, context):
+        yield infered
+nodes.Arguments.assigned_stmts = arguments_assigned_stmts
+
+
+def assign_assigned_stmts(self, node, context=None, asspath=None):
+    if not asspath:
+        yield self.value
+        return
+    for infered in _resolve_asspart(self.value.infer(context), asspath, context):
+        yield infered
+nodes.Assign.assigned_stmts = raise_if_nothing_infered(assign_assigned_stmts)
+nodes.AugAssign.assigned_stmts = raise_if_nothing_infered(assign_assigned_stmts)
+
+
+def _resolve_asspart(parts, asspath, context):
+    """recursive function to resolve multiple assignments"""
+    asspath = asspath[:]
+    index = asspath.pop(0)
+    for part in parts:
+        if hasattr(part, 'getitem'):
+            try:
+                assigned = part.getitem(index, context)
+            # XXX raise a specific exception to avoid potential hiding of
+            # unexpected exception ?
+            except (TypeError, IndexError):
+                return
+            if not asspath:
+                # we achieved to resolved the assignment path, don't infer the
+                # last part
+                yield assigned
+            elif assigned is YES:
+                return
+            else:
+                # we are not yet on the last part of the path search on each
+                # possibly inferred value
+                try:
+                    for infered in _resolve_asspart(assigned.infer(context),
+                                                    asspath, context):
+                        yield infered
+                except InferenceError:
+                    return
+
+
+def excepthandler_assigned_stmts(self, node, context=None, asspath=None):
+    for assigned in unpack_infer(self.type):
+        if isinstance(assigned, nodes.Class):
+            assigned = Instance(assigned)
+        yield assigned
+nodes.ExceptHandler.assigned_stmts = raise_if_nothing_infered(excepthandler_assigned_stmts)
+
+
+def with_assigned_stmts(self, node, context=None, asspath=None):
+    if asspath is None:
+        for lst in self.vars.infer(context):
+            if isinstance(lst, (nodes.Tuple, nodes.List)):
+                for item in lst.nodes:
+                    yield item
+nodes.With.assigned_stmts = raise_if_nothing_infered(with_assigned_stmts)
+
+