271 

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

   273 

   274 from cubicweb.server.pool import PreCommitOperation

   275 

   276 

   277 class PropagateSubjectRelationHook(Hook):

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

   279     events = ('after_add_relation',)

   280     # to set in concrete class

   281     rtype = None

   282     subject_relations = None

   283     object_relations = None

   284     accepts = None # subject_relations + object_relations

   285 

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

   287         for eid in (fromeid, toeid):

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

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

   290                 return

   291         if rtype in self.subject_relations:

   292             meid, seid = fromeid, toeid

   293         else:

   294             assert rtype in self.object_relations

   295             meid, seid = toeid, fromeid

   296         session.unsafe_execute(

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

   298             % (self.rtype, self.rtype, self.rtype),

   299             {'x': meid, 'e': seid}, ('x', 'e'))

   300 

   301 

   302 class PropagateSubjectRelationAddHook(Hook):

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

   304     events = ('after_add_relation',)

   305     # to set in concrete class

   306     rtype = None

   307     subject_relations = None

   308     object_relations = None

   309     accepts = None # (self.rtype,)

   310 

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

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

   313         execute = session.unsafe_execute

   314         for rel in self.subject_relations:

   315             if eschema.has_subject_relation(rel):

   316                 execute('SET R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

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

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

   319         for rel in self.object_relations:

   320             if eschema.has_object_relation(rel):

   321                 execute('SET R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

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

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

   324 

   325 

   326 class PropagateSubjectRelationDelHook(Hook):

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

   328     events = ('after_delete_relation',)

   329     # to set in concrete class

   330     rtype = None

   331     subject_relations = None

   332     object_relations = None

   333     accepts = None # (self.rtype,)

   334 

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

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

   337         execute = session.unsafe_execute

   338         for rel in self.subject_relations:

   339             if eschema.has_subject_relation(rel):

   340                 execute('DELETE R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

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

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

   343         for rel in self.object_relations:

   344             if eschema.has_object_relation(rel):

   345                 execute('DELETE R %s P WHERE X eid %%(x)s, P eid %%(p)s, '

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

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