There is no need to filter objects if there is no objects in resource list

[Guangya Liu (Jay Lau)]

In oslo base filter, it has the following logic, this will cause that get_filtered_objects loop all filters even if there is no objs after filtered by some first filters.

class BaseFilterHandler(base_handler.BaseHandler):
    """Base class to handle loading filter classes.

    This class should be subclassed where one needs to use filters.
    """

    def get_filtered_objects(self, filter_classes, objs,
                             filter_properties):
        for filter_cls in filter_classes:
            objs = filter_cls().filter_all(objs, filter_properties)
        return list(objs)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/65418

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/65418
Committed: https://git.openstack.org/cgit/openstack/oslo-incubator/commit/?id=cae33101b6dadbfd64d9f460ebdea533baace288
Submitter: Jenkins
Branch: master

commit cae33101b6dadbfd64d9f460ebdea533baace288
Author: Jay Lau <email address hidden>
Date: Mon Jan 20 13:11:16 2014 +0800

    Stop looping all filters if no objects return

    In Oslo base filter, get_filtered_objects will loop all filters
    before exit even if some filters return no objects.

    This patch will stop looping all filters if no objects return by
    one filter.

    Change-Id: Ie5b1c477e6cfb9cd004828eb73109ef96b17ff6e
    Closes-Bug: #1266690