class OrderedExtensionOption(ListOption):
def __init__(self, section, name, interface, default=None,
include_missing=True, doc=''):
ListOption.__init__(self, section, name, default, doc=doc)
self.xtnpt = ExtensionPoint(interface)
self.include_missing = include_missing
def __get__(self, instance, owner):
if instance is None:
return self
order = ListOption.__get__(self, instance, owner)
if not order and self.default is not None:
items = filter(None, [item.strip() for item in
self.default.split(self.sep, ',')])
components = []
for impl in self.xtnpt.extensions(instance):
if self.include_missing or impl.__class__.__name__ in order:
components.append(impl)
if not components:
if self.default is not None:
return self.default(instance.env)
raise AttributeError('Cannot find any implementations of the "%s" '
'interface from "%s". Please update the '
'option %s.%s in trac.ini.'
% (self.xtnpt.interface.__name__,
', '.join(order), self.section, self.name))
if order:
def compare(x, y):
x, y = x.__class__.__name__, y.__class__.__name__
if x not in order:
return int(y in order)
if y not in order:
return -int(x in order)
return cmp(order.index(x), order.index(y))
components.sort(compare)
return components
