1 files changed, 41 insertions, 0 deletions
diff --git a/third_party/rust/fluent-langneg/src/accepted_languages.rs b/third_party/rust/fluent-langneg/src/accepted_languages.rs
new file mode 100644
index 0000000000..58cf277703
--- /dev/null
+++ b/third_party/rust/fluent-langneg/src/accepted_languages.rs
@@ -0,0 +1,41 @@
+//! This function parses Accept-Language string into a list of language tags that
+//! can be later passed to language negotiation functions.
+//!
+//! # Example:
+//!
+//! ```
+//! use fluent_langneg::negotiate_languages;
+//! use fluent_langneg::NegotiationStrategy;
+//! use fluent_langneg::parse_accepted_languages;
+//! use fluent_langneg::convert_vec_str_to_langids_lossy;
+//! use unic_langid::LanguageIdentifier;
+//!
+//! let requested = parse_accepted_languages("de-AT;0.9,de-DE;0.8,de;0.7;en-US;0.5");
+//! let available = convert_vec_str_to_langids_lossy(&["fr", "pl", "de", "en-US"]);
+//! let default: LanguageIdentifier = "en-US".parse().expect("Failed to parse a langid.");
+//!
+//! let supported = negotiate_languages(
+//!   &requested,
+//!   &available,
+//!   Some(&default),
+//!   NegotiationStrategy::Filtering
+//! );
+//!
+//! let expected = convert_vec_str_to_langids_lossy(&["de", "en-US"]);
+//! assert_eq!(supported,
+//!            expected.iter().map(|t| t.as_ref()).collect::<Vec<&LanguageIdentifier>>());
+//! ```
+//!
+//! This function ignores the weights associated with the locales, since Fluent Locale
+//! language negotiation only uses the order of locales, not the weights.
+//!
+
+use unic_langid::LanguageIdentifier;
+
+pub fn parse(s: &str) -> Vec<LanguageIdentifier> {
+    s.split(',')
+        .map(|t| t.trim().split(';').nth(0).unwrap())
+        .filter(|t| !t.is_empty())
+        .filter_map(|t| t.parse().ok())
+        .collect()
+}