uptime: locale init per thread

Store a thread-local flag so ensure_uptime_locale() only runs
setup_localization("uptime") once per thread, and call it from every
public API entry point. This lets library consumers get translated
strings even when the current thread did not explicitly initialize the
locale.

Author: karanabe

src/uucore/src/lib/features/uptime.rs

@@ -13,9 +13,11 @@
 // See https://github.com/uutils/coreutils/pull/7289 for discussion.
 
 use crate::error::{UError, UResult};
+use crate::locale::{self, LocalizationError};
 use crate::translate;
 use chrono::Local;
 use libc::time_t;
+use std::cell::Cell;
 use thiserror::Error;
 
 #[derive(Debug, Error)]
@@ -36,6 +38,29 @@ impl UError for UptimeError {
     }
 }
 
+thread_local! {
+    static LOCALE_READY: Cell<bool> = Cell::new(false);
+}
+
+fn ensure_uptime_locale() {
+    LOCALE_READY.with(|ready| {
+        if ready.get() {
+            return;
+        }
+
+        match locale::setup_localization("uptime") {
+            Ok(()) => ready.set(true),
+            Err(LocalizationError::Bundle(msg)) if msg.contains("already initialized") => {
+                ready.set(true);
+            }
+            Err(err) => {
+                #[cfg(debug_assertions)]
+                eprintln!("uucore::uptime localization setup failed: {err}");
+            }
+        }
+    });
+}
+
 /// Returns the formatted time string, e.g. "12:34:56"
 pub fn get_formatted_time() -> String {
     Local::now().time().format("%H:%M:%S").to_string()
@@ -52,6 +77,7 @@ pub fn get_formatted_time() -> String {
 /// Returns a UResult with the uptime in seconds if successful, otherwise an UptimeError.
 #[cfg(target_os = "openbsd")]
 pub fn get_uptime(_boot_time: Option<time_t>) -> UResult<i64> {
+    ensure_uptime_locale();
     use libc::CLOCK_BOOTTIME;
     use libc::clock_gettime;
 
@@ -91,6 +117,7 @@ pub fn get_uptime(_boot_time: Option<time_t>) -> UResult<i64> {
 #[cfg(unix)]
 #[cfg(not(target_os = "openbsd"))]
 pub fn get_uptime(boot_time: Option<time_t>) -> UResult<i64> {
+    ensure_uptime_locale();
     use crate::utmpx::Utmpx;
     use libc::BOOT_TIME;
     use std::fs::File;
@@ -150,6 +177,7 @@ pub fn get_uptime(boot_time: Option<time_t>) -> UResult<i64> {
 /// Returns a UResult with the uptime in seconds if successful, otherwise an UptimeError.
 #[cfg(windows)]
 pub fn get_uptime(_boot_time: Option<time_t>) -> UResult<i64> {
+    ensure_uptime_locale();
     use windows_sys::Win32::System::SystemInformation::GetTickCount;
     // SAFETY: always return u32
     let uptime = unsafe { GetTickCount() };
@@ -167,6 +195,7 @@ pub fn get_uptime(_boot_time: Option<time_t>) -> UResult<i64> {
 /// Returns a UResult with the uptime in a human-readable format(e.g. "1 day, 3:45") if successful, otherwise an UptimeError.
 #[inline]
 pub fn get_formatted_uptime(boot_time: Option<time_t>) -> UResult<String> {
+    ensure_uptime_locale();
     let up_secs = get_uptime(boot_time)?;
 
     if up_secs < 0 {
@@ -307,6 +336,7 @@ pub fn get_nusers() -> usize {
 /// e.g. "0 users", "1 user", "2 users"
 #[inline]
 pub fn format_nusers(n: usize) -> String {
+    ensure_uptime_locale();
     translate!(
         "uptime-user-count",
         "count" => n
@@ -320,6 +350,7 @@ pub fn format_nusers(n: usize) -> String {
 /// e.g. "0 user", "1 user", "2 users"
 #[inline]
 pub fn get_formatted_nusers() -> String {
+    ensure_uptime_locale();
     #[cfg(not(target_os = "openbsd"))]
     return format_nusers(get_nusers());
 
@@ -335,6 +366,7 @@ pub fn get_formatted_nusers() -> String {
 /// The load average is a tuple of three floating point numbers representing the 1-minute, 5-minute, and 15-minute load averages.
 #[cfg(unix)]
 pub fn get_loadavg() -> UResult<(f64, f64, f64)> {
+    ensure_uptime_locale();
     use crate::libc::c_double;
     use libc::getloadavg;
 
@@ -357,6 +389,7 @@ pub fn get_loadavg() -> UResult<(f64, f64, f64)> {
 /// Returns a UResult with an UptimeError.
 #[cfg(windows)]
 pub fn get_loadavg() -> UResult<(f64, f64, f64)> {
+    ensure_uptime_locale();
     Err(UptimeError::WindowsLoadavg)?
 }
 
@@ -368,6 +401,7 @@ pub fn get_loadavg() -> UResult<(f64, f64, f64)> {
 /// e.g. "load average: 0.00, 0.00, 0.00"
 #[inline]
 pub fn get_formatted_loadavg() -> UResult<String> {
+    ensure_uptime_locale();
     let loadavg = get_loadavg()?;
     Ok(translate!(
         "uptime-lib-format-loadavg",
@@ -392,4 +426,24 @@ mod tests {
         assert_eq!("1 user", format_nusers(1));
         assert_eq!("2 users", format_nusers(2));
     }
+
+    #[test]
+    fn test_format_nusers_threaded() {
+        unsafe {
+            std::env::set_var("LANG", "en_US.UTF-8");
+        }
+        let _ = locale::setup_localization("top");
+        let _ = locale::setup_localization("uptime");
+
+        assert_eq!("uptime-user-count", format_nusers(0));
+
+        std::thread::spawn(move || {
+            let _ = locale::setup_localization("uptime");
+            assert_eq!("0 users", format_nusers(0));
+            assert_eq!("1 user", format_nusers(1));
+            assert_eq!("2 users", format_nusers(2));
+        })
+        .join()
+        .expect("thread should succeed");
+    }
 }