class OrderedExtensionsOption(ListOption):
"""A comma separated, ordered, list of components implementing `interface`.
Can be empty.
If `include_missing` is true (the default) all components implementing the
interface are returned, with those specified by the option ordered first."""
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)
components = []
for impl in self.xtnpt.extensions(instance):
if self.include_missing or impl.__class__.__name__ in order:
components.append(impl)
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
class ExtensionOption(Option):
def __init__(self, section, name, interface, default=None, doc=''):
Option.__init__(self, section, name, default, doc)
self.xtnpt = ExtensionPoint(interface)
def __get__(self, instance, owner):
if instance is None:
return self
value = Option.__get__(self, instance, owner)
for impl in self.xtnpt.extensions(instance):
if impl.__class__.__name__ == value:
return impl
raise AttributeError('Cannot find an implementation of the "%s" '
'interface named "%s". Please update the option '
'%s.%s in trac.ini.'
% (self.xtnpt.interface.__name__, value,
self.section, self.name))