Struct icu_provider_adapters::fork::predicates::MissingLocalePredicate

pub struct MissingLocalePredicate;

A predicate that allows forking providers to search for a provider that supports a particular locale, based on whether it returns DataErrorKind::MissingLocale.

Examples

Configure a multi-language data provider pointing at two language packs:

use icu_provider_adapters::fork::ForkByErrorProvider;
use icu_provider_adapters::fork::predicates::MissingLocalePredicate;
use icu_provider_fs::FsDataProvider;
use icu_provider::prelude::*;
use icu_provider::hello_world::HelloWorldV1Marker;
use icu_locid::langid;

// The `tests` directory contains two separate "language packs" for Hello World data.
let provider_de = FsDataProvider::try_new("tests/data/langtest/de").unwrap();
let provider_ro = FsDataProvider::try_new("tests/data/langtest/ro").unwrap();

// Create the forking provider:
let provider = ForkByErrorProvider::new_with_predicate(
    provider_de,
    provider_ro,
    MissingLocalePredicate
);

// Test that we can load both "de" and "ro" data:

let german_hello_world: DataPayload<HelloWorldV1Marker> = provider
    .as_deserializing()
    .load(DataRequest {
        locale: &langid!("de").into(),
        metadata: Default::default(),
    })
    .expect("Loading should succeed")
    .take_payload()
    .expect("Data should be present");

assert_eq!("Hallo Welt", german_hello_world.get().message);

let romanian_hello_world: DataPayload<HelloWorldV1Marker> = provider
    .as_deserializing()
    .load(DataRequest {
        locale: &langid!("ro").into(),
        metadata: Default::default(),
    })
    .expect("Loading should succeed")
    .take_payload()
    .expect("Data should be present");

assert_eq!("Salut, lume", romanian_hello_world.get().message);

// We should not be able to load "en" data because it is not in the provider:

DataProvider::<HelloWorldV1Marker>::load(
    &provider.as_deserializing(),
    DataRequest {
        locale: &langid!("en").into(),
        metadata: Default::default(),
    }
)
.expect_err("No English data");

Trait Implementations

impl Debug for MissingLocalePredicate

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

Formats the value using the given formatter.

impl ForkByErrorPredicate for MissingLocalePredicate

const UNIT_ERROR: DataErrorKind = DataErrorKind::MissingLocale

The error to return if there are zero providers.

fn test(&self, _: DataKey, _: Option<DataRequest<'_>>, err: DataError) -> bool

This function is called when a data request fails and there are additional providers that could possibly fulfill the request.

impl PartialEq for MissingLocalePredicate

fn eq(&self, other: &MissingLocalePredicate) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for MissingLocalePredicate

impl StructuralPartialEq for MissingLocalePredicate