--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/hooks/email.py	Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,80 @@
+# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb 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.
+#
+# CubicWeb 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 CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+"""hooks to ensure use_email / primary_email relations consistency"""
+
+__docformat__ = "restructuredtext en"
+
+from cubicweb.server import hook
+
+
+class SetUseEmailRelationOp(hook.Operation):
+    """delay this operation to commit to avoid conflict with a late rql query
+    already setting the relation
+    """
+    rtype = 'use_email'
+    entity = email = None # make pylint happy
+
+    def condition(self):
+        """check entity has use_email set for the email address"""
+        return not any(e for e in self.entity.use_email
+                       if self.email.eid == e.eid)
+
+    def precommit_event(self):
+        if self.cnx.deleted_in_transaction(self.entity.eid):
+            return
+        if self.cnx.deleted_in_transaction(self.email.eid):
+            return
+        if self.condition():
+            self.cnx.execute(
+                'SET X %s Y WHERE X eid %%(x)s, Y eid %%(y)s' % self.rtype,
+                {'x': self.entity.eid, 'y': self.email.eid})
+
+
+class SetPrimaryEmailRelationOp(SetUseEmailRelationOp):
+    rtype = 'primary_email'
+
+    def condition(self):
+        """check entity has no primary_email set"""
+        return not self.entity.primary_email
+
+
+class SetPrimaryEmailHook(hook.Hook):
+    """notify when a bug or story or version has its state modified"""
+    __regid__ = 'setprimaryemail'
+    __select__ = hook.Hook.__select__ & hook.match_rtype('use_email')
+    category = 'email'
+    events = ('after_add_relation',)
+
+    def __call__(self):
+        entity = self._cw.entity_from_eid(self.eidfrom)
+        if 'primary_email' in entity.e_schema.subject_relations():
+            SetPrimaryEmailRelationOp(self._cw, entity=entity,
+                                      email=self._cw.entity_from_eid(self.eidto))
+
+class SetUseEmailHook(hook.Hook):
+    """notify when a bug or story or version has its state modified"""
+    __regid__ = 'setprimaryemail'
+    __select__ = hook.Hook.__select__ & hook.match_rtype('primary_email')
+    category = 'email'
+    events = ('after_add_relation',)
+
+    def __call__(self):
+        entity = self._cw.entity_from_eid(self.eidfrom)
+        if 'use_email' in entity.e_schema.subject_relations():
+            SetUseEmailRelationOp(self._cw, entity=entity,
+                                  email=self._cw.entity_from_eid(self.eidto))