Module dynxso

Dynamically-typed XSOs

This module provides the utilities to make dynamically-typed XSOs work. Dynamically typed XSOs are contained in Xso<dyn Trait>, where Trait is a trait provided by the user.

The given Trait constrains the specific types which can be used in the Xso<dyn Trait> box. This allows users to provide additional methods on the trait which are available on all Xso<dyn Trait> objects via the Deref and DerefMut implementations.

Creating a new Trait

In order to be usable within Xso<dyn Trait>, a trait must satisfy the following constraints:

• dyn Trait must implement DynXso.
• dyn Trait must implement MayContain<T> for all T which implement Trait.

The easiest and most forward-compatible way of providing these implementations is the derive_dyn_traits macro.

Example

trait MyPayload: Any {}

derive_dyn_traits!(MyPayload);

#[derive(FromXml, Debug, PartialEq)]
#[xml(namespace = "urn:example", name = "foo")]
struct Foo;
impl MyPayload for Foo {}
Xso::<dyn MyPayload>::register_type::<Foo>();

#[derive(FromXml, Debug, PartialEq)]
#[xml(namespace = "urn:example", name = "bar")]
struct Bar;
impl MyPayload for Bar {}
Xso::<dyn MyPayload>::register_type::<Bar>();

let x: Xso<dyn MyPayload> = from_bytes("<foo xmlns='urn:example'/>".as_bytes()).unwrap();
assert_eq!(Foo, *x.downcast::<Foo>().unwrap());

let x: Xso<dyn MyPayload> = from_bytes("<bar xmlns='urn:example'/>".as_bytes()).unwrap();
assert_eq!(Bar, *x.downcast::<Bar>().unwrap());

Modules

registry

Helper traits for dynamic XSO builder registries.

xso_vec

Helper types for XsoVec.

Structs

BuilderRegistrystd

Registry for type-erased FromXml builders which construct T

DynBuilder

Wrapper around a FromEventsBuilder to convert a Box<T> output to a Xso<T> output.

UnboxBuilder

Wrapper around a FromEventsBuilder to convert a Box<T> output to a T output.

Xso

Dynamic XSO container

XsoVec

Container for dynamically-typed XSOs optimized for type-keyed access

Enums

TakeOneError

Error type for retrieving a single item from XsoVec.

Traits

DynXso

Dynamic XSO type

MayContain

Declare that T may be held by Box<Self>