v0.30.0

src/traffic.rs

@@ -51,13 +51,16 @@ impl TopTable {
         if raw.is_empty() || weight == 0 {
             return;
         }
+        // Probe with the borrowed label. Under production traffic most methods,
+        // statuses, routes and user agents repeat; allocating a fresh String
+        // for every hit creates avoidable allocator churn.
         let value = truncate(raw, MAX_LABEL_BYTES);
-        if let Some(count) = self.values.get_mut(&value) {
+        if let Some(count) = self.values.get_mut(value) {
             *count = count.saturating_add(weight);
             return;
         }
         if self.values.len() < TOP_CAPACITY {
-            self.values.insert(value, weight);
+            self.values.insert(value.to_owned(), weight);
             return;
         }
         let Some((smallest, minimum)) = self
@@ -69,7 +72,7 @@ impl TopTable {
             return;
         };
         self.values.remove(&smallest);
-        self.values.insert(value, minimum.saturating_add(weight));
+        self.values.insert(value.to_owned(), minimum.saturating_add(weight));
     }
     fn merge(&mut self, other: &Self) {
         for (value, count) in &other.values {
@@ -337,15 +340,15 @@ fn user_agent_family(value: &str) -> &'static str {
     }
 }
 
-fn truncate(value: &str, max_bytes: usize) -> String {
+fn truncate(value: &str, max_bytes: usize) -> &str {
     if value.len() <= max_bytes {
-        return value.to_owned();
+        return value;
     }
     let mut end = max_bytes;
     while !value.is_char_boundary(end) {
         end -= 1;
     }
-    value[..end].to_owned()
+    &value[..end]
 }
 
 #[cfg(test)]