Struct aws_smithy_types::type_erasure::TypeErasedBox

pub struct TypeErasedBox { /* private fields */ }

Abstraction over Box<dyn T + Send + Sync> that provides Debug and optionally Clone.

The orchestrator uses TypeErasedBox to avoid the complication of six or more generic parameters and to avoid the monomorphization that brings with it.

Examples

Creating a box:

use aws_smithy_types::type_erasure::TypeErasedBox;

let boxed = TypeErasedBox::new("some value");

Downcasting a box:

let value: Option<&String> = boxed.downcast_ref::<String>();

Converting a box back into its value:

let boxed = TypeErasedBox::new("some value".to_string());
let value: String = *boxed.downcast::<String>().expect("it is a string");

Implementations

impl TypeErasedBox

pub fn doesnt_matter() -> Self

Available on crate feature test-util only.

Often, when testing the orchestrator or its components, it’s necessary to provide a TypeErasedBox to serve as an Input for invoke. In cases where the type won’t actually be accessed during testing, use this method to generate a TypeErasedBox that makes it clear that “for the purpose of this test, the Input doesn’t matter.”

impl TypeErasedBox

pub fn new<T: Send + Sync + Debug + 'static>(value: T) -> Self

Create a new TypeErasedBox from value of type T

pub fn new_with_clone<T: Send + Sync + Clone + Debug + 'static>( value: T, ) -> Self

Create a new cloneable TypeErasedBox from the given value.

pub fn try_clone(&self) -> Option<Self>

Attempts to clone this box.

Note: this will only ever succeed if the box was created with TypeErasedBox::new_with_clone.

pub fn downcast<T: Debug + Send + Sync + 'static>(self) -> Result<Box<T>, Self>

Downcast into a Box<T>, or return Self if it is not a T.

pub fn downcast_ref<T: Debug + Send + Sync + 'static>(&self) -> Option<&T>

Downcast as a &T, or return None if it is not a T.

pub fn downcast_mut<T: Debug + Send + Sync + 'static>( &mut self, ) -> Option<&mut T>

Downcast as a &mut T, or return None if it is not a T.

Trait Implementations

impl Debug for TypeErasedBox

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<TypeErasedError> for TypeErasedBox

fn from(value: TypeErasedError) -> Self

Converts to this type from the input type.