try:

    from cubicweb.server.sources.pyrorql import PyroRQLSource

except ImportError:

    pass

else:

    from os.path import join

    def load_mapping_file(source):

        mappingfile = source.config['mapping-file']

        mappingfile = join(source.repo.config.apphome, mappingfile)

        mapping = {}

        execfile(mappingfile, mapping)

        for junk in ('__builtins__', '__doc__'):

            mapping.pop(junk, None)

        mapping.setdefault('support_relations', {})

        mapping.setdefault('dont_cross_relations', set())

        mapping.setdefault('cross_relations', set())

        # do some basic checks of the mapping content

        assert 'support_entities' in mapping, \

               'mapping file should at least define support_entities'

        assert isinstance(mapping['support_entities'], dict)

        assert isinstance(mapping['support_relations'], dict)

        assert isinstance(mapping['dont_cross_relations'], set)

        assert isinstance(mapping['cross_relations'], set)

        unknown = set(mapping) - set( ('support_entities', 'support_relations',

                                       'dont_cross_relations', 'cross_relations') )

        assert not unknown, 'unknown mapping attribute(s): %s' % unknown

        # relations that are necessarily not crossed

        for rtype in ('is', 'is_instance_of', 'cw_source'):

            assert rtype not in mapping['dont_cross_relations'], \

                   '%s relation should not be in dont_cross_relations' % rtype

            assert rtype not in mapping['support_relations'], \

                   '%s relation should not be in support_relations' % rtype

        return mapping

    for source in repo.sources_by_uri.values():

        if not isinstance(source, PyroRQLSource):

            continue

        mapping = load_mapping_file(source)

        print 'migrating map for', source