cubicweb_seda/__init__.py
author Sylvain Thénault <sylvain.thenault@logilab.fr>
Tue, 12 Dec 2017 17:57:57 +0100
changeset 2915 451328134bee
parent 2898 8bd8b3533dec
permissions -rw-r--r--
[entities] Add a safety belt avoid unexpected error in some corner case e.g. while debugging an instance I attempted to display result of 'Any X, C WHERE X container C' with unexpectedly to container for the entity, but I wasn't able to display it because rset.one() raised an error since len(rset) was 2. Even if the caller may be wrong, it seems ok to not call rset.one() if function is called in an erroneous context and simply return None in such case.

# copyright 2016-2017 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact 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 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.
#
# 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
"""cubicweb-seda application package

Data Exchange Standard for Archival
"""

from cubicweb_compound import skip_rtypes_set, structure_def, CompositeGraph


# control of compound graph by adding etype / rtype to the corresponding set below
GRAPH_SKIP_ETYPES = set()
GRAPH_SKIP_RTYPES = set(['container', 'clone_of'])


def seda_profile_container_def(schema):
    """Define container for SEDAArchiveTransfer, as a list of (etype, parent_rdefs)."""
    return structure_def(schema, 'SEDAArchiveTransfer',
                         skipetypes=GRAPH_SKIP_ETYPES, skiprtypes=GRAPH_SKIP_RTYPES).items()


def _iter_external_rdefs(eschema, skip_rtypes):
    """Return an iterator on (rdef, role) of external relations from entity schema (i.e.
    non-composite relations).
    """
    for rschema, targets, role in eschema.relation_definitions():
        if rschema in skip_rtypes:
            continue
        for target_etype in targets:
            rdef = eschema.rdef(rschema, role, target_etype)
            if rdef.composite:
                continue
            yield rdef, role


def iter_all_rdefs(schema, container_etype):
    """Return an iterator on (rdef, role) of all relations of the compound graph starting from the
    given entity type, both internal (composite) and external (non-composite).
    """
    graph = CompositeGraph(schema, skipetypes=GRAPH_SKIP_ETYPES, skiprtypes=GRAPH_SKIP_RTYPES)
    skip_external_rtypes = skip_rtypes_set(GRAPH_SKIP_RTYPES)
    stack = [container_etype]
    visited = set(stack)
    while stack:
        etype = stack.pop()
        for (rtype, role), targets in graph.child_relations(etype):
            rschema = schema.rschema(rtype)
            for target in targets:
                if role == 'subject':
                    rdef = rschema.rdefs[(etype, target)]
                else:
                    rdef = rschema.rdefs[(target, etype)]
                yield rdef, role

                if target not in visited:
                    visited.add(target)
                    stack.append(target)
        for rdef, role in _iter_external_rdefs(schema[etype], skip_external_rtypes):
            yield rdef, role