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Quelle response.rs
Sprache: unbekannt
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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 ).
use crate::buf::BufferMarker;
use crate::error::{DataError, DataErrorKind};
use crate::marker::DataMarker;
use crate::request::DataLocale;
use alloc::boxed::Box;
use core::convert::TryFrom;
use core::fmt::Debug;
use core::marker::PhantomData;
use core::ops::Deref;
use yoke::cartable_ptr::CartableOptionPointer;
use yoke::trait_hack::YokeTraitHack;
use yoke::*;
#[cfg(not(feature = "sync"))]
use alloc::rc::Rc as SelectedRc;
#[cfg(feature = "sync")]
use alloc::sync::Arc as SelectedRc;
/// A response object containing metadata about the returned data.
#[derive(Debug, Clone, PartialEq, Default)]
#[non_exhaustive]
pub struct DataResponseMetadata {
/// The resolved locale of the returned data, if locale fallbacking was performed.
pub locale: Option<DataLocale>,
/// The format of the buffer for buffer-backed data, if known (for example, JSON).
pub buffer_format: Option<crate::buf::BufferFormat>,
}
/// A container for data payloads returned from a data provider.
///
/// [`DataPayload`] is built on top of the [`yoke`] framework, which allows for cheap, zero-co py
/// operations on data via the use of self-references.
///
/// The type of the data stored in [`DataPayload`] is determined by the [`DataMarker`] type parameter.
///
/// ## Accessing the data
///
/// To get a reference to the data inside [`DataPayload`], use [`DataPayload::get()`]. If you need
/// to store the data for later use, you need to store the [`DataPayload`] itself, since `get` only
/// returns a reference with an ephemeral lifetime.
///
/// ## Mutating the data
///
/// To modify the data stored in a [`DataPayload`], use [`DataPayload::with_mut()`].
///
/// ## Transforming the data to a different type
///
/// To transform a [`DataPayload`] to a different type backed by the same data store (cart), use
/// [`DataPayload::map_project()`] or one of its sister methods.
///
/// # Cargo feature: `sync`
///
/// By default, the payload uses non-concurrent reference counting internally, and hence is neither
/// [`Sync`] nor [`Send`]; if these traits are required, the `sync` Cargo feature can be enabled.
///
/// # Examples
///
/// Basic usage, using the `HelloWorldV1Marker` marker:
///
/// ```
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
/// use std::borrow::Cow;
///
/// let payload = DataPayload::<HelloWorldV1Marker>::from_owned(HelloWorldV1 {
/// message: Cow::Borrowed("Demo"),
/// });
///
/// assert_eq!("Demo", payload.get().message);
/// ```
pub struct DataPayload<M: DataMarker>(pub(crate) DataPayloadInner<M>);
/// A container for data payloads with storage for something else.
///
/// The type parameter `O` is stored as part of the interior enum, leading to
/// better stack size optimization. `O` can be as large as the [`DataPayload`]
/// minus two words without impacting stack size.
///
/// # Examples
///
/// Create and use DataPayloadOr:
///
/// ```
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
/// use icu_provider::DataPayloadOr;
///
/// let payload: DataPayload<HelloWorldV1Marker> = HelloWorldProvider
/// .load(DataRequest {
/// locale: &"de".parse().unwrap(),
/// metadata: Default::default(),
/// })
/// .expect("Loading should succeed")
/// .take_payload()
/// .expect("Data should be present");
///
/// let payload_some =
/// DataPayloadOr::<HelloWorldV1Marker, ()>::from_payload(payload);
/// let payload_none = DataPayloadOr::<HelloWorldV1Marker, ()>::from_other(());
///
/// assert_eq!(
/// payload_some.get(),
/// Ok(&HelloWorldV1 {
/// message: "Hallo Welt".into()
/// })
/// );
/// assert_eq!(payload_none.get(), Err(&()));
/// ```
///
/// Stack size comparison:
///
/// ```
/// use core::mem::size_of;
/// use icu_provider::prelude::*;
/// use icu_provider::DataPayloadOr;
///
/// const W: usize = size_of::<usize>();
///
/// // SampleStruct is 3 words:
/// # #[icu_provider::data_struct(SampleStructMarker)]
/// # pub struct SampleStruct<'data>(usize, usize, &'data ());
/// assert_eq!(W * 3, size_of::<SampleStruct>());
///
/// // DataPayload adds a word for a total of 4 words:
/// assert_eq!(W * 4, size_of::<DataPayload<SampleStructMarker>>());
///
/// // Option<DataPayload> balloons to 5 words:
/// assert_eq!(W * 5, size_of::<Option<DataPayload<SampleStructMarker>>>());
///
/// // But, using DataPayloadOr is the same size as DataPayload:
/// assert_eq!(W * 4, size_of::<DataPayloadOr<SampleStructMarker, ()>>());
///
/// // The largest optimized Other type is two words smaller than the DataPayload:
/// assert_eq!(W * 4, size_of::<DataPayloadOr<SampleStructMarker, [usize; 1]>>());
/// assert_eq!(W * 4, size_of::<DataPayloadOr<SampleStructMarker, [usize; 2]>>());
/// assert_eq!(W * 5, size_of::<DataPayloadOr<SampleStructMarker, [usize; 3]>>());
/// ```
#[doc(hidden)] // TODO(#4467): establish this as an internal API
pub struct DataPayloadOr<M: DataMarker, O>(pub(crate) DataPayloadOrInner<M, O>);
pub(crate) enum DataPayloadInner<M: DataMarker> {
Yoke(Yoke<M::Yokeable, CartableOptionPointer<CartInner>>),
StaticRef(&'static M::Yokeable),
}
pub(crate) enum DataPayloadOrInner<M: DataMarker, O> {
Yoke(Yoke<M::Yokeable, CartableOptionPointer<CartInner>>),
Inner(DataPayloadOrInnerInner<M, O>),
}
pub(crate) enum DataPayloadOrInnerInner<M: DataMarker, O> {
StaticRef(&'static M::Yokeable),
Other(O),
}
/// The type of the "cart" that is used by [`DataPayload`].
///
/// This type is public but the inner cart type is private. To create a
/// [`Yoke`] with this cart, use [`Cart::try_make_yoke`]. Then, convert
/// it to a [`DataPayload`] with [`DataPayload::from_yoked_buffer`].
#[derive(Clone, Debug)]
#[allow(clippy::redundant_allocation)] // false positive, it's cheaper to wrap an existing Box in an Rc than to reallocate a huge Rc
pub struct Cart(CartInner);
/// The actual cart type (private typedef).
pub(crate) type CartInner = SelectedRc<Box<[u8]>>;
impl Deref for Cart {
type Target = Box<[u8]>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
// Safe because both Rc and Arc are StableDeref, and our impl delegates.
unsafe impl stable_deref_trait::StableDeref for Cart {}
// Safe because both Rc and Arc are CloneableCart, and our impl delegates.
unsafe impl yoke::CloneableCart for Cart {}
impl Cart {
/// Creates a `Yoke<Y, Option<Cart>>` from owned bytes by applying `f`.
pub fn try_make_yoke<Y, F, E>(cart: Box<[u8]>, f: F) -> Result<Yoke<Y, Option<Self>>, E>
where
for<'a> Y: Yokeable<'a>,
F: FnOnce(&[u8]) -> Result<<Y as Yokeable>::Output, E>,
{
Yoke::try_attach_to_cart(SelectedRc::new(cart), |b| f(b))
// Safe because the cart is only wrapped
.map(|yoke| unsafe { yoke.replace_cart(Cart) })
.map(Yoke::wrap_cart_in_option)
}
/// Helper function to convert `Yoke<Y, Option<Cart>>` to `Yoke<Y, Option<CartInner>>`.
#[inline]
pub(crate) fn unwrap_cart<Y>(yoke: Yoke<Y, Option<Cart>>) -> Yoke<Y, Option<CartInner>>
where
for<'a> Y: Yokeable<'a>,
{
// Safety: `Cart` has one field and we are removing it from the newtype,
// and we are preserving it in the new cart, unwrapping it from the newtype.
unsafe { yoke.replace_cart(|option_cart| option_cart.map(|cart| cart.0)) }
}
}
impl<M> Debug for DataPayload<M>
where
M: DataMarker,
for<'a> &'a <M::Yokeable as Yokeable<'a>>::Output: Debug,
{
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
self.get().fmt(f)
}
}
impl<M, O> Debug for DataPayloadOr<M, O>
where
M: DataMarker,
for<'a> &'a <M::Yokeable as Yokeable<'a>>::Output: Debug,
O: Debug,
{
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
self.get()
.map(|v| Debug::fmt(&v, f))
.unwrap_or_else(|v| Debug::fmt(v, f))
}
}
/// Cloning a DataPayload is generally a cheap operation.
/// See notes in the `Clone` impl for [`Yoke`].
///
/// # Examples
///
/// ```no_run
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
///
/// let resp1: DataPayload<HelloWorldV1Marker> = todo!();
/// let resp2 = resp1.clone();
/// ```
impl<M> Clone for DataPayload<M>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Clone,
{
fn clone(&self) -> Self {
Self(match &self.0 {
DataPayloadInner::Yoke(yoke) => DataPayloadInner::Yoke(yoke.clone()),
DataPayloadInner::StaticRef(r) => DataPayloadInner::StaticRef(*r),
})
}
}
impl<M, O> Clone for DataPayloadOr<M, O>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Clone,
O: Clone,
{
fn clone(&self) -> Self {
Self(match &self.0 {
DataPayloadOrInner::Yoke(yoke) => DataPayloadOrInner::Yoke(yoke.clone()),
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::StaticRef(r)) => {
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::StaticRef(*r))
}
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::Other(o)) => {
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::Other(o.clone()))
}
})
}
}
impl<M> PartialEq for DataPayload<M>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: PartialEq,
{
fn eq(&self, other: &Self) -> bool {
YokeTraitHack(self.get()).into_ref() == YokeTraitHack(other.get()).into_ref()
}
}
impl<M, O> PartialEq for DataPayloadOr<M, O>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: PartialEq,
O: Eq,
{
fn eq(&self, other: &Self) -> bool {
match (self.get(), other.get()) {
(Ok(x), Ok(y)) => YokeTraitHack(x).into_ref() == YokeTraitHack(y).into_ref(),
(Err(x), Err(y)) => x == y,
_ => false,
}
}
}
impl<M> Eq for DataPayload<M>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Eq,
{
}
impl<M, O> Eq for DataPayloadOr<M, O>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Eq,
O: Eq,
{
}
#[test]
fn test_clone_eq() {
use crate::hello_world::*;
let p1 = DataPayload::<HelloWorldV1Marker>::from_static_str("Demo");
#[allow(clippy::redundant_clone)]
let p2 = p1.clone();
assert_eq!(p1, p2);
let p1 = DataPayloadOr::<HelloWorldV1Marker, usize>::from_payload(p1);
#[allow(clippy::redundant_clone)]
let p2 = p1.clone();
assert_eq!(p1, p2);
let p3 = DataPayloadOr::<HelloWorldV1Marker, usize>::from_other(555);
#[allow(clippy::redundant_clone)]
let p4 = p3.clone();
assert_eq!(p3, p4);
let p5 = DataPayloadOr::<HelloWorldV1Marker, usize>::from_other(666);
assert_ne!(p3, p5);
assert_ne!(p4, p5);
assert_ne!(p1, p3);
assert_ne!(p1, p4);
assert_ne!(p1, p5);
assert_ne!(p2, p3);
assert_ne!(p2, p4);
assert_ne!(p2, p5);
}
impl<M> DataPayload<M>
where
M: DataMarker,
{
/// Convert a fully owned (`'static`) data struct into a DataPayload.
///
/// This constructor creates `'static` payloads.
///
/// # Examples
///
/// ```
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
/// use std::borrow::Cow;
///
/// let local_struct = HelloWorldV1 {
/// message: Cow::Owned("example".to_owned()),
/// };
///
/// let payload =
/// DataPayload::<HelloWorldV1Marker>::from_owned(local_struct.clone());
///
/// assert_eq!(payload.get(), &local_struct);
/// ```
#[inline]
pub fn from_owned(data: M::Yokeable) -> Self {
Self(DataPayloadInner::Yoke(
Yoke::new_owned(data).convert_cart_into_option_pointer(),
))
}
#[doc(hidden)]
#[inline]
pub const fn from_static_ref(data: &'static M::Yokeable) -> Self {
Self(DataPayloadInner::StaticRef(data))
}
/// Convert a DataPayload that was created via [`DataPayload::from_owned()`] back into the
/// concrete type used to construct it.
pub fn try_unwrap_owned(self) -> Result<M::Yokeable, DataError> {
match self.0 {
DataPayloadInner::Yoke(yoke) => yoke.try_into_yokeable().ok(),
DataPayloadInner::StaticRef(_) => None,
}
.ok_or(DataErrorKind::InvalidState.with_str_context("try_unwrap_owned"))
}
/// Mutate the data contained in this DataPayload.
///
/// For safety, all mutation operations must take place within a helper function that cannot
/// borrow data from the surrounding context.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use icu_provider::hello_world::HelloWorldV1Marker;
/// use icu_provider::prelude::*;
///
/// let mut payload =
/// DataPayload::<HelloWorldV1Marker>::from_static_str("Hello");
///
/// payload.with_mut(|s| s.message.to_mut().push_str(" World"));
///
/// assert_eq!("Hello World", payload.get().message);
/// ```
///
/// To transfer data from the context into the data struct, use the `move` keyword:
///
/// ```
/// use icu_provider::hello_world::HelloWorldV1Marker;
/// use icu_provider::prelude::*;
///
/// let mut payload =
/// DataPayload::<HelloWorldV1Marker>::from_static_str("Hello");
///
/// let suffix = " World";
/// payload.with_mut(move |s| s.message.to_mut().push_str(suffix));
///
/// assert_eq!("Hello World", payload.get().message);
/// ```
pub fn with_mut<'a, F>(&'a mut self, f: F)
where
F: 'static + for<'b> FnOnce(&'b mut <M::Yokeable as Yokeable<'a>>::Output),
M::Yokeable: zerofrom::ZeroFrom<'static, M::Yokeable>,
{
if let DataPayloadInner::StaticRef(r) = self.0 {
self.0 = DataPayloadInner::Yoke(
Yoke::new_owned(zerofrom::ZeroFrom::zero_from(r))
.convert_cart_into_option_pointer(),
);
}
match &mut self.0 {
DataPayloadInner::Yoke(yoke) => yoke.with_mut(f),
_ => unreachable!(),
}
}
/// Borrows the underlying data.
///
/// This function should be used like `Deref` would normally be used. For more information on
/// why DataPayload cannot implement `Deref`, see the `yoke` crate.
///
/// # Examples
///
/// ```
/// use icu_provider::hello_world::HelloWorldV1Marker;
/// use icu_provider::prelude::*;
///
/// let payload = DataPayload::<HelloWorldV1Marker>::from_static_str("Demo");
///
/// assert_eq!("Demo", payload.get().message);
/// ```
#[inline]
#[allow(clippy::needless_lifetimes)]
pub fn get<'a>(&'a self) -> &'a <M::Yokeable as Yokeable<'a>>::Output {
match &self.0 {
DataPayloadInner::Yoke(yoke) => yoke.get(),
DataPayloadInner::StaticRef(r) => Yokeable::transform(*r),
}
}
/// Maps `DataPayload<M>` to `DataPayload<M2>` by projecting it with [`Yoke::map_project`].
///
/// This is accomplished by a function that takes `M`'s data type and returns `M2`'s data
/// type. The function takes a second argument which should be ignored. For more details,
/// see [`Yoke::map_project()`].
///
/// The standard [`DataPayload::map_project()`] function moves `self` and cannot capture any
/// data from its context. Use one of the sister methods if you need these capabilities:
///
/// - [`DataPayload::map_project_cloned()`] if you don't have ownership of `self`
/// - [`DataPayload::try_map_project()`] to bubble up an error
/// - [`DataPayload::try_map_project_cloned()`] to do both of the above
///
/// # Examples
///
/// Map from `HelloWorldV1` to a `Cow<str>` containing just the message:
///
/// ```
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
/// use std::borrow::Cow;
///
/// // A custom marker type is required when using `map_project`. The Yokeable should be the
/// // target type, and the Cart should correspond to the type being transformed.
///
/// struct HelloWorldV1MessageMarker;
/// impl DataMarker for HelloWorldV1MessageMarker {
/// type Yokeable = Cow<'static, str>;
/// }
///
/// let p1: DataPayload<HelloWorldV1Marker> = DataPayload::from_owned(HelloWorldV1 {
/// message: Cow::Borrowed("Hello World"),
/// });
///
/// assert_eq!("Hello World", p1.get().message);
///
/// let p2: DataPayload<HelloWorldV1MessageMarker> = p1.map_project(|obj, _| obj.message);
///
/// // Note: at this point, p1 has been moved.
/// assert_eq!("Hello World", p2.get());
/// ```
#[allow(clippy::type_complexity)]
pub fn map_project<M2, F>(self, f: F) -> DataPayload<M2>
where
M2: DataMarker,
F: for<'a> FnOnce(
<M::Yokeable as Yokeable<'a>>::Output,
PhantomData<&'a ()>,
) -> <M2::Yokeable as Yokeable<'a>>::Output,
M::Yokeable: zerofrom::ZeroFrom<'static, M::Yokeable>,
{
DataPayload(DataPayloadInner::Yoke(
match self.0 {
DataPayloadInner::Yoke(yoke) => yoke,
DataPayloadInner::StaticRef(r) => Yoke::new_owned(zerofrom::ZeroFrom::zero_from(r))
.convert_cart_into_option_pointer(),
}
.map_project(f),
))
}
/// Version of [`DataPayload::map_project()`] that borrows `self` instead of moving `self`.
///
/// # Examples
///
/// Same example as above, but this time, do not move out of `p1`:
///
/// ```
/// // Same imports and definitions as above
/// # use icu_provider::hello_world::*;
/// # use icu_provider::prelude::*;
/// # use std::borrow::Cow;
/// # struct HelloWorldV1MessageMarker;
/// # impl DataMarker for HelloWorldV1MessageMarker {
/// # type Yokeable = Cow<'static, str>;
/// # }
///
/// let p1: DataPayload<HelloWorldV1Marker> =
/// DataPayload::from_owned(HelloWorldV1 {
/// message: Cow::Borrowed("Hello World"),
/// });
///
/// assert_eq!("Hello World", p1.get().message);
///
/// let p2: DataPayload<HelloWorldV1MessageMarker> =
/// p1.map_project_cloned(|obj, _| obj.message.clone());
///
/// // Note: p1 is still valid.
/// assert_eq!(p1.get().message, *p2.get());
/// ```
#[allow(clippy::type_complexity)]
pub fn map_project_cloned<'this, M2, F>(&'this self, f: F) -> DataPayload<M2>
where
M2: DataMarker,
F: for<'a> FnOnce(
&'this <M::Yokeable as Yokeable<'a>>::Output,
PhantomData<&'a ()>,
) -> <M2::Yokeable as Yokeable<'a>>::Output,
{
DataPayload(DataPayloadInner::Yoke(match &self.0 {
DataPayloadInner::Yoke(yoke) => yoke.map_project_cloned(f),
DataPayloadInner::StaticRef(r) => {
let output: <M2::Yokeable as Yokeable<'static>>::Output =
f(Yokeable::transform(*r), PhantomData);
// Safety: <M2::Yokeable as Yokeable<'static>>::Output is the same type as M2::Yokeable;
// we're going from 'static to 'static, however in a generic context it's not
// clear to the compiler that that is the case. We have to use the unsafe make API to do this.
let yokeable: M2::Yokeable = unsafe { M2::Yokeable::make(output) };
Yoke::new_owned(yokeable).convert_cart_into_option_pointer()
}
}))
}
/// Version of [`DataPayload::map_project()`] that bubbles up an error from `f`.
///
/// # Examples
///
/// Same example as above, but bubble up an error:
///
/// ```
/// // Same imports and definitions as above
/// # use icu_provider::hello_world::*;
/// # use icu_provider::prelude::*;
/// # use std::borrow::Cow;
/// # struct HelloWorldV1MessageMarker;
/// # impl DataMarker for HelloWorldV1MessageMarker {
/// # type Yokeable = Cow<'static, str>;
/// # }
///
/// let p1: DataPayload<HelloWorldV1Marker> =
/// DataPayload::from_owned(HelloWorldV1 {
/// message: Cow::Borrowed("Hello World"),
/// });
///
/// assert_eq!("Hello World", p1.get().message);
///
/// let string_to_append = "Extra";
/// let p2: DataPayload<HelloWorldV1MessageMarker> =
/// p1.try_map_project(|mut obj, _| {
/// if obj.message.is_empty() {
/// return Err("Example error");
/// }
/// obj.message.to_mut().push_str(string_to_append);
/// Ok(obj.message)
/// })?;
///
/// assert_eq!("Hello WorldExtra", p2.get());
/// # Ok::<(), &'static str>(())
/// ```
#[allow(clippy::type_complexity)]
pub fn try_map_project<M2, F, E>(self, f: F) -> Result<DataPayload<M2>, E>
where
M2: DataMarker,
F: for<'a> FnOnce(
<M::Yokeable as Yokeable<'a>>::Output,
PhantomData<&'a ()>,
) -> Result<<M2::Yokeable as Yokeable<'a>>::Output, E>,
M::Yokeable: zerofrom::ZeroFrom<'static, M::Yokeable>,
{
Ok(DataPayload(DataPayloadInner::Yoke(
match self.0 {
DataPayloadInner::Yoke(yoke) => yoke,
DataPayloadInner::StaticRef(r) => Yoke::new_owned(zerofrom::ZeroFrom::zero_from(r))
.convert_cart_into_option_pointer(),
}
.try_map_project(f)?,
)))
}
/// Version of [`DataPayload::map_project_cloned()`] that bubbles up an error from `f`.
///
/// # Examples
///
/// Same example as above, but bubble up an error:
///
/// ```
/// // Same imports and definitions as above
/// # use icu_provider::hello_world::*;
/// # use icu_provider::prelude::*;
/// # use std::borrow::Cow;
/// # struct HelloWorldV1MessageMarker;
/// # impl DataMarker for HelloWorldV1MessageMarker {
/// # type Yokeable = Cow<'static, str>;
/// # }
///
/// let p1: DataPayload<HelloWorldV1Marker> =
/// DataPayload::from_owned(HelloWorldV1 {
/// message: Cow::Borrowed("Hello World"),
/// });
///
/// assert_eq!("Hello World", p1.get().message);
///
/// let string_to_append = "Extra";
/// let p2: DataPayload<HelloWorldV1MessageMarker> = p1
/// .try_map_project_cloned(|obj, _| {
/// if obj.message.is_empty() {
/// return Err("Example error");
/// }
/// let mut message = obj.message.clone();
/// message.to_mut().push_str(string_to_append);
/// Ok(message)
/// })?;
///
/// // Note: p1 is still valid, but the values no longer equal.
/// assert_ne!(p1.get().message, *p2.get());
/// assert_eq!("Hello WorldExtra", p2.get());
/// # Ok::<(), &'static str>(())
/// ```
#[allow(clippy::type_complexity)]
pub fn try_map_project_cloned<'this, M2, F, E>(&'this self, f: F) -> Result<DataPayload<M2>, E>
where
M2: DataMarker,
F: for<'a> FnOnce(
&'this <M::Yokeable as Yokeable<'a>>::Output,
PhantomData<&'a ()>,
) -> Result<<M2::Yokeable as Yokeable<'a>>::Output, E>,
{
Ok(DataPayload(DataPayloadInner::Yoke(match &self.0 {
DataPayloadInner::Yoke(yoke) => yoke.try_map_project_cloned(f)?,
DataPayloadInner::StaticRef(r) => {
let output: <M2::Yokeable as Yokeable<'static>>::Output =
f(Yokeable::transform(*r), PhantomData)?;
// Safety: <M2::Yokeable as Yokeable<'static>>::Output is the same type as M2::Yokeable
Yoke::new_owned(unsafe { M2::Yokeable::make(output) })
.convert_cart_into_option_pointer()
}
})))
}
/// Convert between two [`DataMarker`] types that are compatible with each other
/// with compile-time type checking.
///
/// This happens if they both have the same [`DataMarker::Yokeable`] type.
///
/// Can be used to erase the key of a data payload in cases where multiple keys correspond
/// to the same data struct.
///
/// For runtime dynamic casting, use [`DataPayload::dynamic_cast_mut()`].
///
/// # Examples
///
/// ```no_run
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
///
/// struct CustomHelloWorldV1Marker;
/// impl DataMarker for CustomHelloWorldV1Marker {
/// type Yokeable = HelloWorldV1<'static>;
/// }
///
/// let hello_world: DataPayload<HelloWorldV1Marker> = todo!();
/// let custom: DataPayload<CustomHelloWorldV1Marker> = hello_world.cast();
/// ```
#[inline]
pub fn cast<M2>(self) -> DataPayload<M2>
where
M2: DataMarker<Yokeable = M::Yokeable>,
{
DataPayload(match self.0 {
DataPayloadInner::Yoke(yoke) => DataPayloadInner::Yoke(yoke),
DataPayloadInner::StaticRef(r) => DataPayloadInner::StaticRef(r),
})
}
/// Convert a mutable reference of a [`DataPayload`] to another mutable reference
/// of the same type with runtime type checking.
///
/// Primarily useful to convert from a generic to a concrete marker type.
///
/// If the `M2` type argument does not match the true marker type, a `DataError` is returned.
///
/// For compile-time static casting, use [`DataPayload::cast()`].
///
/// # Examples
///
/// Change the results of a particular request based on key:
///
/// ```
/// use icu_locid::locale;
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
///
/// struct MyWrapper<P> {
/// inner: P,
/// }
///
/// impl<M, P> DataProvider<M> for MyWrapper<P>
/// where
/// M: KeyedDataMarker,
/// P: DataProvider<M>,
/// {
/// #[inline]
/// fn load(&self, req: DataRequest) -> Result<DataResponse<M>, DataError> {
/// let mut res = self.inner.load(req)?;
/// if let Some(ref mut generic_payload) = res.payload {
/// let mut cast_result =
/// generic_payload.dynamic_cast_mut::<HelloWorldV1Marker>();
/// if let Ok(ref mut concrete_payload) = cast_result {
/// // Add an emoji to the hello world message
/// concrete_payload.with_mut(|data| {
/// data.message.to_mut().insert_str(0, "✨ ");
/// });
/// }
/// }
/// Ok(res)
/// }
/// }
///
/// let provider = MyWrapper {
/// inner: HelloWorldProvider,
/// };
/// let formatter =
/// HelloWorldFormatter::try_new_unstable(&provider, &locale!("de").into())
/// .unwrap();
///
/// assert_eq!(formatter.format_to_string(), "✨ Hallo Welt");
/// ```
#[inline]
pub fn dynamic_cast_mut<M2>(&mut self) -> Result<&mut DataPayload<M2>, DataError>
where
M2: DataMarker,
{
let this: &mut dyn core::any::Any = self;
if let Some(this) = this.downcast_mut() {
Ok(this)
} else {
Err(DataError::for_type::<M2>().with_str_context(core::any::type_name::<M>()))
}
}
}
impl DataPayload<BufferMarker> {
/// Converts an owned byte buffer into a `DataPayload<BufferMarker>`.
pub fn from_owned_buffer(buffer: Box<[u8]>) -> Self {
let yoke = Yoke::attach_to_cart(SelectedRc::new(buffer), |b| &**b)
.wrap_cart_in_option()
.convert_cart_into_option_pointer();
Self(DataPayloadInner::Yoke(yoke))
}
/// Converts a yoked byte buffer into a `DataPayload<BufferMarker>`.
pub fn from_yoked_buffer(yoke: Yoke<&'static [u8], Option<Cart>>) -> Self {
let yoke = Cart::unwrap_cart(yoke);
Self(DataPayloadInner::Yoke(
yoke.convert_cart_into_option_pointer(),
))
}
/// Converts a static byte buffer into a `DataPayload<BufferMarker>`.
pub fn from_static_buffer(buffer: &'static [u8]) -> Self {
Self(DataPayloadInner::Yoke(
Yoke::new_owned(buffer).convert_cart_into_option_pointer(),
))
}
}
impl<M> Default for DataPayload<M>
where
M: DataMarker,
M::Yokeable: Default,
{
fn default() -> Self {
Self::from_owned(Default::default())
}
}
impl<M, O> DataPayloadOr<M, O>
where
M: DataMarker,
{
/// Creates a [`DataPayloadOr`] from a [`DataPayload`].
#[inline]
pub fn from_payload(payload: DataPayload<M>) -> Self {
match payload.0 {
DataPayloadInner::Yoke(yoke) => Self(DataPayloadOrInner::Yoke(yoke)),
DataPayloadInner::StaticRef(r) => Self(DataPayloadOrInner::Inner(
DataPayloadOrInnerInner::StaticRef(r),
)),
}
}
/// Creates a [`DataPayloadOr`] from the other type `O`.
#[inline]
pub fn from_other(other: O) -> Self {
Self(DataPayloadOrInner::Inner(DataPayloadOrInnerInner::Other(
other,
)))
}
/// Gets the value from this [`DataPayload`] as `Ok` or the other type as `Err`.
#[allow(clippy::needless_lifetimes)]
#[inline]
pub fn get<'a>(&'a self) -> Result<&'a <M::Yokeable as Yokeable<'a>>::Output, &'a O> {
match &self.0 {
DataPayloadOrInner::Yoke(yoke) => Ok(yoke.get()),
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::StaticRef(r)) => {
Ok(Yokeable::transform(*r))
}
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::Other(o)) => Err(o),
}
}
/// Consumes this [`DataPayloadOr`], returning either the wrapped
/// [`DataPayload`] or the other type.
#[inline]
pub fn into_inner(self) -> Result<DataPayload<M>, O> {
match self.0 {
DataPayloadOrInner::Yoke(yoke) => Ok(DataPayload(DataPayloadInner::Yoke(yoke))),
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::StaticRef(r)) => {
Ok(DataPayload(DataPayloadInner::StaticRef(r)))
}
DataPayloadOrInner::Inner(DataPayloadOrInnerInner::Other(o)) => Err(o),
}
}
}
/// A response object containing an object as payload and metadata about it.
#[allow(clippy::exhaustive_structs)] // this type is stable
pub struct DataResponse<M>
where
M: DataMarker,
{
/// Metadata about the returned object.
pub metadata: DataResponseMetadata,
/// The object itself; `None` if it was not loaded.
pub payload: Option<DataPayload<M>>,
}
impl<M> DataResponse<M>
where
M: DataMarker,
{
/// Takes ownership of the underlying payload. Error if not present.
///
/// To take the metadata, too, use [`Self::take_metadata_and_payload()`].
#[inline]
pub fn take_payload(self) -> Result<DataPayload<M>, DataError> {
Ok(self.take_metadata_and_payload()?.1)
}
/// Takes ownership of the underlying metadata and payload. Error if payload is not present.
#[inline]
pub fn take_metadata_and_payload(
self,
) -> Result<(DataResponseMetadata, DataPayload<M>), DataError> {
Ok((
self.metadata,
self.payload
.ok_or_else(|| DataErrorKind::MissingPayload.with_type_context::<M>())?,
))
}
/// Convert between two [`DataMarker`] types that are compatible with each other
/// with compile-time type checking.
///
/// This happens if they both have the same [`DataMarker::Yokeable`] type.
///
/// Can be used to erase the key of a data payload in cases where multiple keys correspond
/// to the same data struct.
///
/// For runtime dynamic casting, use [`DataPayload::dynamic_cast_mut()`].
#[inline]
pub fn cast<M2>(self) -> DataResponse<M2>
where
M2: DataMarker<Yokeable = M::Yokeable>,
{
match self.payload {
Some(payload) => DataResponse {
metadata: self.metadata,
payload: Some(payload.cast()),
},
None => DataResponse {
metadata: self.metadata,
payload: None,
},
}
}
}
impl<M> TryFrom<DataResponse<M>> for DataPayload<M>
where
M: DataMarker,
{
type Error = DataError;
fn try_from(response: DataResponse<M>) -> Result<Self, Self::Error> {
response.take_payload()
}
}
impl<M> Debug for DataResponse<M>
where
M: DataMarker,
for<'a> &'a <M::Yokeable as Yokeable<'a>>::Output: Debug,
{
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
write!(
f,
"DataResponse {{ metadata: {:?}, payload: {:?} }}",
self.metadata, self.payload
)
}
}
/// Cloning a DataResponse is generally a cheap operation.
/// See notes in the `Clone` impl for [`Yoke`].
///
/// # Examples
///
/// ```no_run
/// use icu_provider::hello_world::*;
/// use icu_provider::prelude::*;
///
/// let resp1: DataResponse<HelloWorldV1Marker> = todo!();
/// let resp2 = resp1.clone();
/// ```
impl<M> Clone for DataResponse<M>
where
M: DataMarker,
for<'a> YokeTraitHack<<M::Yokeable as Yokeable<'a>>::Output>: Clone,
{
fn clone(&self) -> Self {
Self {
metadata: self.metadata.clone(),
payload: self.payload.clone(),
}
}
}
#[test]
fn test_debug() {
use crate::hello_world::*;
use alloc::borrow::Cow;
let resp = DataResponse::<HelloWorldV1Marker> {
metadata: Default::default(),
payload: Some(DataPayload::from_owned(HelloWorldV1 {
message: Cow::Borrowed("foo"),
})),
};
assert_eq!("DataResponse { metadata: DataResponseMetadata { locale: None, buffer_format: None }, payload: Some(HelloWorldV1 { message: \"foo\" }) }", format!("{resp:?}"));
}
[ Dauer der Verarbeitung: 0.36 Sekunden
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2026-04-04
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