Class DelegateMethod

motor/metaprogramming.py:214–248

A method on the wrapped PyMongo object that does no I/O and can be called synchronously

class DelegateMethod(ReadOnlyProperty):
    """A method on the wrapped PyMongo object that does no I/O and can be called
    synchronously"""

    def __init__(self, doc=None):
        ReadOnlyProperty.__init__(self, doc)
        self.wrap_class = None

    def wrap(self, original_class):
        self.wrap_class = original_class
        return self

    def create_attribute(self, cls, attr_name):
        if self.wrap_class is None:
            return ReadOnlyProperty.create_attribute(self, cls, attr_name)

        method = getattr(cls.__delegate_class__, attr_name)
        original_class = self.wrap_class

        @functools.wraps(method)
        def wrapper(self_, *args, **kwargs):
            result = method(self_.delegate, *args, **kwargs)

            # Don't call isinstance(), not checking subclasses.
            if result.__class__ == original_class:
                # Delegate to the current object to wrap the result.
                return self_.wrap(result)
            else:
                return result

        if self.doc:
            wrapper.__doc__ = self.doc

        wrapper.is_wrap_method = True  # For Synchro.
        return wrapper


class MotorCursorChainingMethod(MotorAttributeFactory):