feat(limiter): add Limiter struct with clock interface and tests

Cargo.lock

@@ -1199,6 +1199,10 @@ dependencies = [
  "sys-locale",
 ]
 
+[[package]]
+name = "clash-verge-limiter"
+version = "0.1.0"
+
 [[package]]
 name = "clash-verge-logging"
 version = "0.1.0"

Cargo.toml

@@ -5,7 +5,7 @@ members = [
   "crates/clash-verge-logging",
   "crates/clash-verge-signal",
   "crates/tauri-plugin-clash-verge-sysinfo",
-  "crates/clash-verge-i18n",
+  "crates/clash-verge-i18n", "crates/clash-verge-limiter",
 ]
 resolver = "2"
 

crates/clash-verge-limiter/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "clash-verge-limiter"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+
+[lints]
+workspace = true

crates/clash-verge-limiter/src/lib.rs

@@ -0,0 +1,163 @@
+use std::sync::Arc;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+pub trait Clock: Send + Sync {
+    fn now_ms(&self) -> u64;
+}
+
+impl<T: Clock + ?Sized> Clock for &T {
+    fn now_ms(&self) -> u64 {
+        (**self).now_ms()
+    }
+}
+
+impl<T: Clock + ?Sized> Clock for Arc<T> {
+    fn now_ms(&self) -> u64 {
+        (**self).now_ms()
+    }
+}
+
+pub struct SystemClock;
+
+impl Clock for SystemClock {
+    fn now_ms(&self) -> u64 {
+        SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_millis() as u64
+    }
+}
+
+pub struct Limiter<C: Clock = SystemClock> {
+    last_run_ms: AtomicU64,
+    period_ms: u64,
+    clock: C,
+}
+
+impl<C: Clock> Limiter<C> {
+    pub fn new(period: Duration, clock: C) -> Self {
+        Self {
+            last_run_ms: AtomicU64::new(0),
+            period_ms: period.as_millis() as u64,
+            clock,
+        }
+    }
+
+    pub fn check(&self) -> bool {
+        let now = self.clock.now_ms();
+        let last = self.last_run_ms.load(Ordering::Relaxed);
+
+        if now < last + self.period_ms && now >= last {
+            return false;
+        }
+
+        self.last_run_ms
+            .compare_exchange(last, now, Ordering::SeqCst, Ordering::Relaxed)
+            .is_ok()
+    }
+}
+
+#[cfg(test)]
+mod extra_tests {
+    use super::*;
+    use std::sync::Arc;
+    use std::thread;
+
+    struct MockClock(AtomicU64);
+    impl Clock for MockClock {
+        fn now_ms(&self) -> u64 {
+            self.0.load(Ordering::SeqCst)
+        }
+    }
+
+    #[test]
+    fn test_zero_period_always_passes() {
+        let mock = MockClock(AtomicU64::new(100));
+        let limiter = Limiter::new(Duration::from_millis(0), &mock);
+
+        assert!(limiter.check());
+        assert!(limiter.check());
+    }
+
+    #[test]
+    fn test_boundary_condition() {
+        let period_ms = 100;
+        let mock = MockClock(AtomicU64::new(1000));
+        let limiter = Limiter::new(Duration::from_millis(period_ms), &mock);
+
+        assert!(limiter.check());
+
+        mock.0.store(1099, Ordering::SeqCst);
+        assert!(!limiter.check());
+
+        mock.0.store(1100, Ordering::SeqCst);
+        assert!(limiter.check(), "Should pass exactly at period boundary");
+    }
+
+    #[test]
+    fn test_high_concurrency_consistency() {
+        let period = Duration::from_millis(1000);
+        let mock = Arc::new(MockClock(AtomicU64::new(1000)));
+        let limiter = Arc::new(Limiter::new(period, Arc::clone(&mock)));
+
+        assert!(limiter.check());
+
+        mock.0.store(2500, Ordering::SeqCst);
+
+        let mut handles = vec![];
+        for _ in 0..20 {
+            let l = Arc::clone(&limiter);
+            handles.push(thread::spawn(move || l.check()));
+        }
+
+        #[allow(clippy::unwrap_used)]
+        let results: Vec<bool> = handles.into_iter().map(|h| h.join().unwrap()).collect();
+
+        let success_count = results.iter().filter(|&&x| x).count();
+        assert_eq!(success_count, 1);
+
+        assert_eq!(limiter.last_run_ms.load(Ordering::SeqCst), 2500);
+    }
+
+    #[test]
+    fn test_extreme_time_jump() {
+        let mock = MockClock(AtomicU64::new(100));
+        let limiter = Limiter::new(Duration::from_millis(100), &mock);
+
+        assert!(limiter.check());
+
+        mock.0.store(u64::MAX - 10, Ordering::SeqCst);
+        assert!(limiter.check());
+    }
+
+    #[test]
+    fn test_system_clock_real_path() {
+        let clock = SystemClock;
+        let start = clock.now_ms();
+        assert!(start > 0);
+
+        std::thread::sleep(Duration::from_millis(10));
+        assert!(clock.now_ms() >= start);
+    }
+
+    #[test]
+    fn test_limiter_with_system_clock_default() {
+        let limiter = Limiter::new(Duration::from_millis(100), SystemClock);
+        assert!(limiter.check());
+    }
+
+    #[test]
+    fn test_coverage_time_backward() {
+        let mock = MockClock(AtomicU64::new(5000));
+        let limiter = Limiter::new(Duration::from_millis(100), &mock);
+
+        assert!(limiter.check());
+
+        mock.0.store(4000, Ordering::SeqCst);
+
+        assert!(limiter.check(), "Should pass and reset when time moves backward");
+
+        assert_eq!(limiter.last_run_ms.load(Ordering::SeqCst), 4000);
+    }
+}