Trait BufferProvider

Source

pub trait BufferProvider {
    // Required method
    fn load_buffer(
        &self,
        key: DataKey,
        req: DataRequest<'_>,
    ) -> Result<DataResponse<BufferMarker>, DataError>;
}

Expand description

A data provider that returns opaque bytes.

Generally, these bytes are expected to be deserializable with Serde. To get an object implementing DataProvider via Serde, use as_deserializing().

Passing a BufferProvider to a *_with_buffer_provider constructor requires enabling the deserialization Cargo feature for the expected format(s):

deserialize_json
deserialize_postcard_1
deserialize_bincode_1

Along with DataProvider, this is one of the two foundational traits in this crate.

BufferProvider can be made into a trait object. It is used over FFI.

§Examples

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

let buffer_provider = HelloWorldProvider.into_json_provider();

let req = DataRequest {
    locale: &langid!("de").into(),
    metadata: Default::default(),
};

// Deserializing manually
assert_eq!(
    serde_json::from_slice::<HelloWorldV1>(
        buffer_provider
            .load_buffer(HelloWorldV1Marker::KEY, req)
            .expect("load should succeed")
            .take_payload()
            .unwrap()
            .get()
    )
    .expect("should deserialize"),
    HelloWorldV1 {
        message: Cow::Borrowed("Hallo Welt"),
    },
);

// Deserialize automatically
let deserializing_provider: &dyn DataProvider<HelloWorldV1Marker> =
    &buffer_provider.as_deserializing();

assert_eq!(
    deserializing_provider
        .load(req)
        .expect("load should succeed")
        .take_payload()
        .unwrap()
        .get(),
    &HelloWorldV1 {
        message: Cow::Borrowed("Hallo Welt"),
    },
);