third_party/logilab/astroid/mixins.py

# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of astroid.
#
# astroid 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.
#
# astroid 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 astroid. If not, see <http://www.gnu.org/licenses/>.
"""This module contains some mixins for the different nodes.
"""

from logilab.common.decorators import cachedproperty

from astroid.exceptions import (AstroidBuildingException, InferenceError,
                                NotFoundError)


class BlockRangeMixIn(object):
    """override block range """

    @cachedproperty
    def blockstart_tolineno(self):
        return self.lineno

    def _elsed_block_range(self, lineno, orelse, last=None):
        """handle block line numbers range for try/finally, for, if and while
        statements
        """
        if lineno == self.fromlineno:
            return lineno, lineno
        if orelse:
            if lineno >= orelse[0].fromlineno:
                return lineno, orelse[-1].tolineno
            return lineno, orelse[0].fromlineno - 1
        return lineno, last or self.tolineno


class FilterStmtsMixin(object):
    """Mixin for statement filtering and assignment type"""

    def _get_filtered_stmts(self, _, node, _stmts, mystmt):
        """method used in _filter_stmts to get statemtents and trigger break"""
        if self.statement() is mystmt:
            # original node's statement is the assignment, only keep
            # current node (gen exp, list comp)
            return [node], True
        return _stmts, False

    def ass_type(self):
        return self


class AssignTypeMixin(object):

    def ass_type(self):
        return self

    def _get_filtered_stmts(self, lookup_node, node, _stmts, mystmt):
        """method used in filter_stmts"""
        if self is mystmt:
            return _stmts, True
        if self.statement() is mystmt:
            # original node's statement is the assignment, only keep
            # current node (gen exp, list comp)
            return [node], True
        return _stmts, False


class ParentAssignTypeMixin(AssignTypeMixin):

    def ass_type(self):
        return self.parent.ass_type()


class FromImportMixIn(FilterStmtsMixin):
    """MixIn for From and Import Nodes"""

    def _infer_name(self, frame, name):
        return name

    def do_import_module(self, modname=None):
        """return the ast for a module whose name is <modname> imported by <self>
        """
        # handle special case where we are on a package node importing a module
        # using the same name as the package, which may end in an infinite loop
        # on relative imports
        # XXX: no more needed ?
        mymodule = self.root()
        level = getattr(self, 'level', None) # Import as no level
        if modname is None:
            modname = self.modname
        # XXX we should investigate deeper if we really want to check
        # importing itself: modname and mymodule.name be relative or absolute
        if mymodule.relative_to_absolute_name(modname, level) == mymodule.name:
            # FIXME: we used to raise InferenceError here, but why ?
            return mymodule
        try:
            return mymodule.import_module(modname, level=level)
        except AstroidBuildingException:
            raise InferenceError(modname)
        except SyntaxError as ex:
            raise InferenceError(str(ex))

    def real_name(self, asname):
        """get name from 'as' name"""
        for name, _asname in self.names:
            if name == '*':
                return asname
            if not _asname:
                name = name.split('.', 1)[0]
                _asname = name
            if asname == _asname:
                return name
        raise NotFoundError(asname)