271 

   272 # base classes for relation propagation ########################################

   273 

   274 from cubicweb.server.pool import PreCommitOperation

   275 

   276 class RQLPrecommitOperation(PreCommitOperation):

   277     def precommit_event(self):

   278         execute = self.session.unsafe_execute

   279         for rql in self.rqls:

   280             execute(*rql)

   281 

   282 

   283 class PropagateSubjectRelationHook(Hook):

   284     """propagate permissions and nosy list when new entity are added"""

   285     events = ('after_add_relation',)

   286     # to set in concrete class

   287     rtype = None

   288     subject_relations = None

   289     object_relations = None

   290     accepts = None # subject_relations + object_relations

   291 

   292     def call(self, session, fromeid, rtype, toeid):

   293         for eid in (fromeid, toeid):

   294             etype = session.describe(eid)[0]

   295             if not self.schema.eschema(etype).has_subject_relation(self.rtype):

   296                 return

   297         if rtype in self.subject_relations:

   298             meid, seid = fromeid, toeid

   299         else:

   300             assert rtype in self.object_relations

   301             meid, seid = toeid, fromeid

   302         rql = 'SET E %s P WHERE X %s P, X eid %%(x)s, E eid %%(e)s, NOT E %s P'\

   303               % (self.rtype, self.rtype, self.rtype)

   304         rqls = [(rql, {'x': meid, 'e': seid}, ('x', 'e'))]

   305         RQLPrecommitOperation(session, rqls=rqls)

   306 

   307 

   308 class PropagateSubjectRelationAddHook(Hook):

   309     """propagate on existing entities when a permission or nosy list is added"""

   310     events = ('after_add_relation',)

   311     # to set in concrete class

   312     rtype = None

   313     subject_relations = None

   314     object_relations = None

   315     accepts = None # (self.rtype,)

   316 

   317     def call(self, session, fromeid, rtype, toeid):

   318         eschema = self.schema.eschema(session.describe(fromeid)[0])

   319         rqls = []

   320         for rel in self.subject_relations:

   321             if eschema.has_subject_relation(rel):

   322                 rqls.append(('SET R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

   323                              'X %s R, NOT R %s P' % (rtype, rel, rtype),

   324                              {'x': fromeid, 'p': toeid}, 'x'))

   325         for rel in self.object_relations:

   326             if eschema.has_object_relation(rel):

   327                 rqls.append(('SET R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

   328                              'R %s X, NOT R %s P' % (rtype, rel, rtype),

   329                              {'x': fromeid, 'p': toeid}, 'x'))

   330         if rqls:

   331             RQLPrecommitOperation(session, rqls=rqls)

   332 

   333 

   334 class PropagateSubjectRelationDelHook(Hook):

   335     """propagate on existing entities when a permission is deleted"""

   336     events = ('after_delete_relation',)

   337     # to set in concrete class

   338     rtype = None

   339     subject_relations = None

   340     object_relations = None

   341     accepts = None # (self.rtype,)

   342 

   343     def call(self, session, fromeid, rtype, toeid):

   344         eschema = self.schema.eschema(session.describe(fromeid)[0])

   345         rqls = []

   346         for rel in self.subject_relations:

   347             if eschema.has_subject_relation(rel):

   348                 rqls.append(('DELETE R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

   349                              'X %s R' % (rtype, rel),

   350                              {'x': fromeid, 'p': toeid}, 'x'))

   351         for rel in self.object_relations:

   352             if eschema.has_object_relation(rel):

   353                 rqls.append(('DELETE R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

   354                              'R %s X' % (rtype, rel),

   355                              {'x': fromeid, 'p': toeid}, 'x'))

   356         if rqls:

   357             RQLPrecommitOperation(session, rqls=rqls)