icu_provider_adapters/
fixed.rs

1// This file is part of ICU4X. For terms of use, please see the file
2// called LICENSE at the top level of the ICU4X source tree
3// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5//! Data provider always serving the same struct.
6
7use core::fmt;
8use icu_provider::prelude::*;
9use yoke::Yokeable;
10
11/// A data provider that returns clones of a fixed type-erased payload.
12///
13/// # Examples
14///
15/// ```
16/// use icu_provider::hello_world::*;
17/// use icu_provider::prelude::*;
18/// use icu_provider_adapters::fixed::FixedProvider;
19/// use std::borrow::Cow;
20/// use writeable::assert_writeable_eq;
21///
22/// let provider = FixedProvider::<HelloWorldV1>::from_static(&HelloWorld {
23///     message: Cow::Borrowed("custom hello world"),
24/// });
25///
26/// // Check that it works:
27/// let formatter =
28///     HelloWorldFormatter::try_new_unstable(&provider, Default::default())
29///         .expect("marker matches");
30/// assert_writeable_eq!(formatter.format(), "custom hello world");
31/// ```
32#[allow(clippy::exhaustive_structs)] // this type is stable
33pub struct FixedProvider<M: DataMarker> {
34    data: DataPayload<M>,
35}
36
37impl<M: DataMarker> FixedProvider<M> {
38    /// Creates a `FixedProvider` with an owned (allocated) payload of the given data.
39    pub fn from_owned(data: M::DataStruct) -> Self {
40        Self::from_payload(DataPayload::from_owned(data))
41    }
42
43    /// Creates a `FixedProvider` with a statically borrowed payload of the given data.
44    pub fn from_static(data: &'static M::DataStruct) -> Self {
45        FixedProvider {
46            data: DataPayload::from_static_ref(data),
47        }
48    }
49
50    /// Creates a `FixedProvider` from an existing [`DataPayload`].
51    pub fn from_payload(data: DataPayload<M>) -> Self {
52        FixedProvider { data }
53    }
54
55    /// Creates a `FixedProvider` with the default (allocated) version of the data struct.
56    pub fn new_default() -> Self
57    where
58        M::DataStruct: Default,
59    {
60        Self::from_owned(M::DataStruct::default())
61    }
62}
63
64impl<M> DataProvider<M> for FixedProvider<M>
65where
66    M: DataMarker,
67    for<'a> <M::DataStruct as Yokeable<'a>>::Output: Clone,
68{
69    fn load(&self, _: DataRequest) -> Result<DataResponse<M>, DataError> {
70        Ok(DataResponse {
71            metadata: Default::default(),
72            payload: self.data.clone(),
73        })
74    }
75}
76
77impl<M> fmt::Debug for FixedProvider<M>
78where
79    M: DynamicDataMarker,
80    M: DataMarker,
81    for<'a> &'a <M::DataStruct as Yokeable<'a>>::Output: fmt::Debug,
82{
83    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
84        self.data.fmt(f)
85    }
86}
icu_provider_adapters/fixed.rs

icu_provider_adapters/
fixed.rs
