namespace_test.py

# Performance test for coaster.sqlalchemy.registry.InstanceRegistry
import timeit


class Registry:
    def __init__(self, param=None):
        self.param = param


class Namespacer1:
    def __init__(self, registry, obj):
        self.__registry = registry
        self.__obj = obj
        self.__param = registry.param

    def __getattr__(self, attr):
        if self.__param is not None:
            return (self.__registry, self.__obj, self.__param)
        else:
            return (self.__registry, self.__obj)


class Namespacer2:
    def __init__(self, registry, obj):
        self.__registry = registry
        self.__obj = obj

    def __getattr__(self, attr):
        if self.__registry.param is not None:
            return (self.__registry, self.__obj, self.__registry.param)
        else:
            return (self.__registry, self.__obj)


class Namespacer3:
    def __init__(self, registry, obj):
        self.__registry = registry
        self.__obj = obj

    def __getattr__(self, attr):
        param = self.__registry.param
        if param is not None:
            return (self.__registry, self.__obj, param)
        else:
            return (self.__registry, self.__obj)


r1 = Registry('obj')
r2 = Registry()

if __name__ == '__main__':
    # Performance, fastest to slowest:
    # 3 (local var), 2 (namespaced access), 1 (instance var)
    print(timeit.timeit('a = Namespacer3(r2, r2); a.x', globals=globals()))
    print(timeit.timeit('a = Namespacer2(r2, r2); a.x', globals=globals()))
    print(timeit.timeit('a = Namespacer1(r2, r2); a.x', globals=globals()))
    print(timeit.timeit('a = Namespacer3(r1, r1); a.x', globals=globals()))
    print(timeit.timeit('a = Namespacer2(r1, r1); a.x', globals=globals()))
    print(timeit.timeit('a = Namespacer1(r1, r1); a.x', globals=globals()))

Sample output:

0.7106772370025283
0.7376894779954455
0.8034342819955782
0.7945575620033196
0.8243368799958262
0.8580065710048075