pub struct MissingLocalePredicate;
Expand description

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§

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impl Debug for MissingLocalePredicate

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

Formats the value using the given formatter. Read more
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impl ForkByErrorPredicate for MissingLocalePredicate

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const UNIT_ERROR: DataErrorKind = DataErrorKind::MissingLocale

The error to return if there are zero providers.
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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. Read more
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impl PartialEq for MissingLocalePredicate

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

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

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impl StructuralPartialEq for MissingLocalePredicate

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> ErasedDestructor for T
where T: 'static,

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impl<T> MaybeSendSync for T