Struct AnyPayload

pub struct AnyPayload { /* private fields */ }

A type-erased data payload.

The only useful method on this type is AnyPayload::downcast(), which transforms this into a normal DataPayload which you can subsequently access or mutate.

As with DataPayload, cloning is designed to be cheap.

Implementations

impl AnyPayload

pub fn downcast<M>(self) -> Result<DataPayload<M>, DataError>

where M: DataMarker, M::Yokeable: ZeroFrom<'static, M::Yokeable> + MaybeSendSync, for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Clone,

Transforms a type-erased AnyPayload into a concrete DataPayload<M>.

Because it is expected that the call site knows the identity of the AnyPayload (e.g., from the data request), this function returns a DataError if the generic type does not match the type stored in the AnyPayload.

pub fn downcast_cloned<M>(&self) -> Result<DataPayload<M>, DataError>

where M: DataMarker, M::Yokeable: ZeroFrom<'static, M::Yokeable> + MaybeSendSync, for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Clone,

Clones and then transforms a type-erased AnyPayload into a concrete DataPayload<M>.

pub fn from_static_ref<Y>(static_ref: &'static Y) -> Self

where Y: for<'a> Yokeable<'a>,

Creates an AnyPayload from a static reference to a data struct.

Examples

use icu_provider::hello_world::*;
use icu_provider::prelude::*;
use std::borrow::Cow;

const HELLO_DATA: HelloWorldV1<'static> = HelloWorldV1 {
    message: Cow::Borrowed("Custom Hello World"),
};

let any_payload = AnyPayload::from_static_ref(&HELLO_DATA);

let payload: DataPayload<HelloWorldV1Marker> =
    any_payload.downcast().expect("TypeId matches");
assert_eq!("Custom Hello World", payload.get().message);

Trait Implementations

impl Clone for AnyPayload

fn clone(&self) -> AnyPayload

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AnyPayload

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

Formats the value using the given formatter.

impl<'a> Yokeable<'a> for AnyPayload

where Self: Sized,

type Output = AnyPayload

This type MUST be Self with the 'static replaced with 'a, i.e. Self<'a>

fn transform(&self) -> &Self::Output

This method must cast self between &'a Self<'static> and &'a Self<'a>.

fn transform_owned(self) -> Self::Output

This method must cast self between Self<'static> and Self<'a>.

unsafe fn make(this: Self::Output) -> Self

This method can be used to cast away Self<'a>’s lifetime.

fn transform_mut<F>(&'a mut self, f: F)

where F: 'static + for<'b> FnOnce(&'b mut Self::Output),

This method must cast self between &'a mut Self<'static> and &'a mut Self<'a>, and pass it to f.