diff -r 000000000000 -r b97547f5f1fa sobjects/email.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sobjects/email.py	Wed Nov 05 15:52:50 2008 +0100
@@ -0,0 +1,63 @@
+"""hooks to ensure use_email / primary_email relations consistency
+
+:organization: Logilab
+:copyright: 2001-2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
+"""
+__docformat__ = "restructuredtext en"
+
+from cubicweb.server.hooksmanager import Hook
+from cubicweb.server.pool import PreCommitOperation
+
+class SetUseEmailRelationOp(PreCommitOperation):
+    """delay this operation to commit to avoid conflict with a late rql query
+    already setting the relation
+    """
+    rtype = 'use_email'
+
+    def condition(self):
+        """check entity has use_email set for the email address"""
+        return not self.session.unsafe_execute(
+            'Any X WHERE X eid %(x)s, X use_email Y, Y eid %(y)s',
+            {'x': self.fromeid, 'y': self.toeid}, 'x')
+    
+    def precommit_event(self):
+        session = self.session
+        if self.condition():
+            session.unsafe_execute(
+                'SET X %s Y WHERE X eid %%(x)s, Y eid %%(y)s' % self.rtype,
+                {'x': self.fromeid, 'y': self.toeid}, 'x')
+    
+class SetPrimaryEmailRelationOp(SetUseEmailRelationOp):
+    rtype = 'primary_email'
+    
+    def condition(self):
+        """check entity has no primary_email set"""
+        return not self.session.unsafe_execute(
+            'Any X WHERE X eid %(x)s, X primary_email Y',
+            {'x': self.fromeid}, 'x')
+
+    
+class SetPrimaryEmailHook(Hook):
+    """notify when a bug or story or version has its state modified"""
+    events = ('after_add_relation',)
+    accepts = ('use_email',)
+    
+    def call(self, session, fromeid, rtype, toeid):
+        subjtype = session.describe(fromeid)[0]
+        eschema = self.vreg.schema[subjtype]
+        if 'primary_email' in eschema.subject_relations():
+            SetPrimaryEmailRelationOp(session, vreg=self.vreg, 
+                                      fromeid=fromeid, toeid=toeid)
+
+class SetUseEmailHook(Hook):
+    """notify when a bug or story or version has its state modified"""
+    events = ('after_add_relation',)
+    accepts = ('primary_email',)
+    
+    def call(self, session, fromeid, rtype, toeid):
+        subjtype = session.describe(fromeid)[0]
+        eschema = self.vreg.schema[subjtype]
+        if 'use_email' in eschema.subject_relations():
+            SetUseEmailRelationOp(session, vreg=self.vreg, 
+                                  fromeid=fromeid, toeid=toeid)