feat: LinkRx::recv_async

Author: Devdutt Shenoi

rumqttd/src/link/local.rs

@@ -338,6 +338,23 @@ impl LinkRx {
         }
     }
 
+    pub async fn recv_async(&mut self) -> Result<Option<Notification>, LinkError> {
+        // Read from cache first
+        // One router_rx trigger signifies a bunch of notifications. So we
+        // should always check cache first
+        match self.cache.pop_front() {
+            Some(v) => Ok(Some(v)),
+            None => {
+                // If cache is empty, check for router trigger and get fresh notifications
+                self.router_rx.recv_async().await?;
+                // Collect 'all' the data in the buffer after a notification.
+                // Notification means fresh data which isn't previously collected
+                mem::swap(&mut *self.send_buffer.lock(), &mut self.cache);
+                Ok(self.cache.pop_front())
+            }
+        }
+    }
+
     pub fn recv_deadline(&mut self, deadline: Instant) -> Result<Option<Notification>, LinkError> {
         // Read from cache first
         // One router_rx trigger signifies a bunch of notifications. So we