feat: add dependency

javascript-engine/external/iana-time-zone/haiku/src/lib.rs

@@ -0,0 +1,68 @@
+#![warn(clippy::all)]
+#![warn(clippy::cargo)]
+#![warn(clippy::undocumented_unsafe_blocks)]
+#![allow(unknown_lints)]
+#![warn(missing_copy_implementations)]
+#![warn(missing_debug_implementations)]
+#![warn(missing_docs)]
+#![warn(rust_2018_idioms)]
+#![warn(trivial_casts, trivial_numeric_casts)]
+#![warn(unsafe_op_in_unsafe_fn)]
+#![warn(unused_qualifications)]
+#![warn(variant_size_differences)]
+
+//! # iana-time-zone-haiku
+//!
+//! [![Crates.io](https://img.shields.io/crates/v/iana-time-zone-haiku.svg)](https://crates.io/crates/iana-time-zone-haiku)
+//! [![Documentation](https://docs.rs/iana-time-zone/badge.svg)](https://docs.rs/iana-time-zone/)
+//! [![Crate License](https://img.shields.io/crates/l/iana-time-zone-haiku-haiku.svg)](https://crates.io/crates/iana-time-zone-haiku)
+//! [![build](https://github.com/strawlab/iana-time-zone/workflows/build/badge.svg?branch=main)](https://github.com/strawlab/iana-time-zone/actions?query=branch%3Amain)
+//!
+//! [iana-time-zone](https://github.com/strawlab/iana-time-zone) support crate for Haiku OS.
+
+#[cxx::bridge(namespace = "iana_time_zone_haiku")]
+mod ffi {
+    // SAFETY: in here "unsafe" is simply part of the syntax
+    unsafe extern "C++" {
+        include!("iana-time-zone-haiku/src/interface.h");
+
+        fn get_tz(buf: &mut [u8]) -> usize;
+    }
+}
+
+/// Get the current IANA time zone as a string.
+///
+/// On Haiku platforms this function will return [`Some`] with the timezone string
+/// or [`None`] if an error occurs. On all other platforms, [`None`] is returned.
+///
+/// # Examples
+///
+/// ```
+/// let timezone = iana_time_zone_haiku::get_timezone();
+/// ```
+pub fn get_timezone() -> Option<String> {
+    // The longest name in the IANA time zone database is 25 ASCII characters long.
+    let mut buf = [0u8; 32];
+    let len = ffi::get_tz(&mut buf);
+    // The name should not be empty, or excessively long.
+    match buf.get(..len)? {
+        b"" => None,
+        s => Some(std::str::from_utf8(s).ok()?.to_owned()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    #[cfg(not(target_os = "haiku"))]
+    fn test_fallback_on_non_haiku_platforms() {
+        assert!(super::get_timezone().is_none());
+    }
+
+    #[test]
+    #[cfg(target_os = "haiku")]
+    fn test_retrieve_time_zone_on_haiku_platforms() {
+        let timezone = super::get_timezone().unwrap();
+        assert!(!timezone.is_empty());
+    }
+}