Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 84 insertions, 0 deletions

diff --git a/third_party/rust/fluent-fallback/src/env.rs b/third_party/rust/fluent-fallback/src/env.rs
new file mode 100644
index 0000000000..cf340fcfdf
--- /dev/null
+++ b/third_party/rust/fluent-fallback/src/env.rs
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+//! Traits required to provide environment driven data for [`Localization`](crate::Localization).
+//!
+//! Since [`Localization`](crate::Localization) is a long-lived structure,
+//! the model in which the user provides ability for the system to react to changes
+//! is by implementing the given environmental trait and triggering
+//! [`Localization::on_change`](crate::Localization::on_change) method.
+//!
+//! At the moment just a single trait is provided, which allows the
+//! environment to feed a selection of locales to be provided to the instance.
+//!
+//! The locales provided to [`Localization`](crate::Localization) should be
+//! already negotiated to ensure that the resources in those locales
+//! are available. The list should also be sorted according to the user
+//! preference, as the order is significant for how [`Localization`](crate::Localization) performs
+//! fallbacking.
+use unic_langid::LanguageIdentifier;
+
+/// A trait used to provide a selection of locales to be used by the
+/// [`Localization`](crate::Localization) instance for runtime
+/// locale fallbacking.
+///
+/// # Example
+/// ```
+/// use fluent_fallback::{Localization, env::LocalesProvider};
+/// use fluent_resmgr::ResourceManager;
+/// use unic_langid::LanguageIdentifier;
+/// use std::{
+///     rc::Rc,
+///     cell::RefCell
+/// };
+///
+/// #[derive(Clone)]
+/// struct Env {
+///     locales: Rc<RefCell<Vec<LanguageIdentifier>>>,
+/// }
+///
+/// impl Env {
+///     pub fn new(locales: Vec<LanguageIdentifier>) -> Self {
+///         Self { locales: Rc::new(RefCell::new(locales)) }
+///     }
+///
+///     pub fn set_locales(&mut self, new_locales: Vec<LanguageIdentifier>) {
+///         let mut locales = self.locales.borrow_mut();
+///         locales.clear();
+///         locales.extend(new_locales);
+///     }
+/// }
+///
+/// impl LocalesProvider for Env {
+///     type Iter = <Vec<LanguageIdentifier> as IntoIterator>::IntoIter;
+///     fn locales(&self) -> Self::Iter {
+///         self.locales.borrow().clone().into_iter()
+///     }
+/// }
+///
+/// let res_mgr = ResourceManager::new("./path/{locale}/".to_string());
+///
+/// let mut env = Env::new(vec![
+///     "en-GB".parse().unwrap()
+/// ]);
+///
+/// let mut loc = Localization::with_env(vec![], true, env.clone(), res_mgr);
+///
+/// env.set_locales(vec![
+///     "de".parse().unwrap(),
+///     "en-GB".parse().unwrap(),
+/// ]);
+///
+/// loc.on_change();
+///
+/// // The next format call will attempt to localize to `de` first and
+/// // fallback on `en-GB`.
+/// ```
+pub trait LocalesProvider {
+    type Iter: Iterator<Item = LanguageIdentifier>;
+    fn locales(&self) -> Self::Iter;
+}
+
+impl LocalesProvider for Vec<LanguageIdentifier> {
+    type Iter = <Vec<LanguageIdentifier> as IntoIterator>::IntoIter;
+    fn locales(&self) -> Self::Iter {
+        self.clone().into_iter()
+    }
+}