Adding upstream version 1.67.1+dfsg1.upstream/1.67.1+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/vendor/icu_provider/src/marker.rs b/vendor/icu_provider/src/marker.rs
new file mode 100644
index 000000000..870885797
--- /dev/null
+++ b/vendor/icu_provider/src/marker.rs
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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 ).
+
+//! Marker types and traits for DataProvider.
+
+use crate::key::DataKey;
+use crate::yoke::Yokeable;
+
+/// Trait marker for data structs. All types delivered by the data provider must be associated with
+/// something implementing this trait.
+///
+/// Structs implementing this trait are normally generated with the [`data_struct`] macro.
+///
+/// By convention, the non-standard `Marker` suffix is used by types implementing DataMarker.
+///
+/// In addition to a marker type implementing DataMarker, the following impls must also be present
+/// for the data struct:
+///
+/// - `impl<'a> Yokeable<'a>` (required)
+/// - `impl ZeroFrom<Self>`
+///
+/// Also see [`KeyedDataMarker`].
+///
+/// # Examples
+///
+/// Manually implementing DataMarker for a custom type:
+///
+/// ```
+/// use icu_provider::prelude::*;
+/// use icu_provider::yoke::*;
+/// use icu_provider::zerofrom::*;
+/// use std::borrow::Cow;
+/// use std::rc::Rc;
+///
+/// #[derive(Yokeable, ZeroFrom)]
+/// struct MyDataStruct<'data> {
+///     message: Cow<'data, str>,
+/// }
+///
+/// struct MyDataStructMarker;
+///
+/// impl DataMarker for MyDataStructMarker {
+///     type Yokeable = MyDataStruct<'static>;
+/// }
+///
+/// // We can now use MyDataStruct with DataProvider:
+/// let s = MyDataStruct {
+///     message: Cow::Owned("Hello World".into()),
+/// };
+/// let payload = DataPayload::<MyDataStructMarker>::from_owned(s);
+/// assert_eq!(payload.get().message, "Hello World");
+/// ```
+///
+/// [`data_struct`]: crate::data_struct
+pub trait DataMarker {
+    /// A type that implements [`Yokeable`]. This should typically be the `'static` version of a
+    /// data struct.
+    type Yokeable: for<'a> Yokeable<'a>;
+}
+
+/// A [`DataMarker`] with a [`DataKey`] attached.
+///
+/// Structs implementing this trait are normally generated with the [`data_struct!`] macro.
+///
+/// Implementing this trait enables this marker to be used with the main [`DataProvider`] trait.
+/// Most markers should be associated with a specific key and should therefore implement this
+/// trait.
+///
+/// [`BufferMarker`] and [`AnyMarker`] are examples of markers that do _not_ implement this trait
+/// because they are not specific to a single key.
+///
+/// [`data_struct!`]: crate::data_struct
+/// [`DataProvider`]: crate::DataProvider
+/// [`BufferMarker`]: crate::BufferMarker
+/// [`AnyMarker`]: crate::AnyMarker
+pub trait KeyedDataMarker: DataMarker {
+    /// The single [`DataKey`] associated with this marker.
+    const KEY: DataKey;
+}