Ability to set limits

crates/librqbit/src/limits.rs

@@ -1,6 +1,8 @@
+use std::sync::Arc;
 use std::time::Duration;
 
 use leaky_bucket::RateLimiter;
+use parking_lot::RwLock;
 use peer_binary_protocol::PIECE_MESSAGE_DEFAULT_LEN;
 use serde::Deserialize;
 use serde::Serialize;
@@ -11,38 +13,68 @@ pub struct LimitsConfig {
     pub download_bps: Option<usize>,
 }
 
-#[derive(Default)]
-pub struct Limits {
-    down: Option<leaky_bucket::RateLimiter>,
-    up: Option<leaky_bucket::RateLimiter>,
-}
+struct Limit(RwLock<Arc<Option<leaky_bucket::RateLimiter>>>);
 
-impl Limits {
-    pub fn new(config: LimitsConfig) -> Self {
-        let new = |bps: usize| -> RateLimiter {
-            let b_per_100_ms = bps.div_ceil(10);
+impl Limit {
+    fn new_inner(bps: Option<usize>) -> Arc<Option<leaky_bucket::RateLimiter>> {
+        let bps = match bps {
+            Some(bps) => bps,
+            None => return Arc::new(None),
+        };
+        let b_per_100_ms = bps.div_ceil(10);
+        Arc::new(Some(
             RateLimiter::builder()
                 .interval(Duration::from_millis(100))
                 .refill(b_per_100_ms)
                 // whatever the limit is, we need to be able to download / upload a chunk
                 .max(PIECE_MESSAGE_DEFAULT_LEN.max(bps))
-                .build()
-        };
+                .build(),
+        ))
+    }
+
+    fn new(bps: Option<usize>) -> Self {
+        Self(RwLock::new(Self::new_inner(bps)))
+    }
+
+    async fn acquire(&self, size: usize) {
+        let lim = self.0.read().clone();
+        if let Some(rl) = lim.as_ref() {
+            rl.acquire(size).await
+        }
+    }
+
+    fn set(&self, limit: Option<usize>) {
+        let new = Self::new_inner(limit);
+        *self.0.write() = new;
+    }
+}
+
+pub struct Limits {
+    down: Limit,
+    up: Limit,
+}
+
+impl Limits {
+    pub fn new(config: LimitsConfig) -> Self {
         Self {
-            down: config.download_bps.map(new),
-            up: config.upload_bps.map(new),
+            down: Limit::new(config.download_bps),
+            up: Limit::new(config.upload_bps),
         }
     }
 
     pub async fn prepare_for_upload(&self, len: usize) {
-        if let Some(rl) = self.up.as_ref() {
-            rl.acquire(len).await;
-        }
+        self.up.acquire(len).await
     }
 
     pub async fn prepare_for_download(&self, len: usize) {
-        if let Some(rl) = self.down.as_ref() {
-            rl.acquire(len).await;
-        }
+        self.down.acquire(len).await
+    }
+
+    pub fn set_upload_bps(&self, bps: Option<usize>) {
+        self.up.set(bps);
+    }
+
+    pub fn set_download_bps(&self, bps: Option<usize>) {
+        self.down.set(bps);
     }
 }