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// This file is part of ICU4X. For terms of use, please see the file // called LICENSE at the top level of the ICU4X source tree // (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ). //! Locale-invariant data provider that requires no I/O. use crate::error::Error; use crate::iter::IterableDataProviderCore; use crate::prelude::*; use std::borrow::Cow; use std::fmt::Debug; /// A locale-invariant data provider. Sometimes useful for testing. Not intended to be used in /// production environments. /// /// The objects returned by [`InvariantDataProvider`] are guaranteed to conform to the correct struct /// definition, so [`InvariantDataProvider`] can also be used to validate unknown data providers. /// /// # Examples /// /// ``` /// use icu_provider::prelude::*; /// use icu_provider::inv::InvariantDataProvider; /// use icu_provider::hello_world::{key, HelloWorldV1}; /// use std::borrow::Cow; /// /// let provider = InvariantDataProvider; /// let result: Cow<HelloWorldV1> = provider /// .load_payload(&DataRequest::from(key::HELLO_WORLD_V1)) /// .unwrap() /// .payload.take() /// .unwrap(); /// /// assert_eq!("(und) Hello World", result.message); /// ``` pub struct InvariantDataProvider; impl<'d, T> DataProvider<'d, T> for InvariantDataProvider where T: Clone + Debug + Default + 'd, { fn load_payload(&self, _req: &DataRequest) -> Result<DataResponse<'d, T>, Error> { Ok(DataResponse { metadata: DataResponseMetadata::default(), payload: DataPayload { cow: Some(Cow::Owned(T::default())), }, }) } } impl IterableDataProviderCore for InvariantDataProvider { fn supported_options_for_key( &self, _resc_key: &ResourceKey, ) -> Result<Box<dyn Iterator<Item = ResourceOptions>>, Error> { let list: Vec<ResourceOptions> = vec![ResourceOptions::default()]; Ok(Box::new(list.into_iter())) } }