+
−"""This file contains some basic registerers required by application objects
+
−registry to handle registration at startup time.
+
−
+
−A registerer is responsible to tell if an object should be registered according
+
−to the application's schema or to already registered object
+
−
+
−:organization: Logilab
+
−:copyright: 2006-2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+
−:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
+
−"""
+
−__docformat__ = "restructuredtext en"
+
−
+
−from cubicweb.vregistry import registerer, yes_registerer
+
−from cubicweb.cwvreg import use_interfaces
+
−
+
−class priority_registerer(registerer):
+
−    """systematically kick previous registered class and register the
+
−    wrapped class (based on the fact that directory containing vobjects
+
−    are loaded from the most generic to the most specific).
+
−
+
−    This is usually for templates or startup views where we want to
+
−    keep only the latest in the load path
+
−    """
+
−    def do_it_yourself(self, registered):
+
−        if registered:
+
−            if len(registered) > 1:
+
−                self.warning('priority_registerer found more than one registered objects '
+
−                             '(registerer monkey patch ?)')
+
−            for regobj in registered[:]:
+
−                self.kick(registered, regobj)
+
−        return self.vobject
+
−    
+
−    def remove_equivalents(self, registered):
+
−        for _obj in registered[:]:
+
−            if self.equivalent(_obj):
+
−                self.kick(registered, _obj)
+
−                break
+
−            
+
−    def remove_all_equivalents(self, registered):
+
−        for _obj in registered[:]:
+
−            if _obj is self.vobject:
+
−                continue
+
−            if self.equivalent(_obj):
+
−                self.kick(registered, _obj)
+
−
+
−    def equivalent(self, other):
+
−        raise NotImplementedError(self, self.vobject)
+
−    
+
−
+
−class accepts_registerer(priority_registerer):
+
−    """register according to the .accepts attribute of the wrapped
+
−    class, which should be a tuple refering some entity's types
+
−
+
−    * if no type is defined the application'schema, skip the wrapped
+
−      class
+
−    * if the class defines a requires attribute, each entity type defined
+
−      in the requires list must be in the schema
+
−    * if an object previously registered has equivalent .accepts
+
−      attribute, kick it out
+
−    * register
+
−    """
+
−    def do_it_yourself(self, registered):
+
−        # if object is accepting interface, we have register it now and
+
−        # remove it later if no object is implementing accepted interfaces
+
−        if use_interfaces(self.vobject):
+
−            return self.vobject
+
−        self.remove_equivalents(registered)
+
−        return self.vobject
+
−    
+
−    def equivalent(self, other):
+
−        if use_interfaces(self.vobject) != use_interfaces(other):
+
−            return False
+
−        try:
+
−            newaccepts = list(other.accepts)
+
−            for etype in self.vobject.accepts:
+
−                try:
+
−                    newaccepts.remove(etype)
+
−                except ValueError:
+
−                    continue
+
−            if newaccepts:
+
−                other.accepts = tuple(newaccepts)
+
−                return False
+
−            return True
+
−        except AttributeError:
+
−            return False
+
−
+
−
+
−__all__ = [cls.__name__ for cls in globals().values()
+
−           if isinstance(cls, type) and issubclass(cls, registerer)
+
−           and not cls is registerer]