feat(mdns): change mdns::Event to hold Vec

protocols/mdns/CHANGELOG.md

@@ -1,15 +1,20 @@
 ## 0.44.0 - unreleased
 
+- Change `mdns::Event` to hold `Vec` and remove `DiscoveredAddrsIter` and `ExpiredAddrsIter`.
+  See [PR 3621].
+
 - Raise MSRV to 1.65.
   See [PR 3715].
 
+[PR 3621]: https://github.com/libp2p/rust-libp2p/pull/3621
 [PR 3715]: https://github.com/libp2p/rust-libp2p/pull/3715
 
 ## 0.43.1
 
 - Derive `Clone` for `mdns::Event`. See [PR 3606].
 
 [PR 3606]: https://github.com/libp2p/rust-libp2p/pull/3606
+
 ## 0.43.0
 
 - Update to `libp2p-core` `v0.39.0`.

protocols/mdns/src/behaviour.rs

@@ -285,7 +285,7 @@ where
             }
         }
         // Emit discovered event.
-        let mut discovered = SmallVec::<[(PeerId, Multiaddr); 4]>::new();
+        let mut discovered = Vec::new();
         for iface_state in self.iface_states.values_mut() {
             while let Poll::Ready((peer, addr, expiration)) =
                 iface_state.poll(cx, &self.listen_addresses)
@@ -304,15 +304,13 @@ where
             }
         }
         if !discovered.is_empty() {
-            let event = Event::Discovered(DiscoveredAddrsIter {
-                inner: discovered.into_iter(),
-            });
+            let event = Event::Discovered(discovered);
             return Poll::Ready(ToSwarm::GenerateEvent(event));
         }
         // Emit expired event.
         let now = Instant::now();
         let mut closest_expiration = None;
-        let mut expired = SmallVec::<[(PeerId, Multiaddr); 4]>::new();
+        let mut expired = Vec::new();
         self.discovered_nodes.retain(|(peer, addr, expiration)| {
             if *expiration <= now {
                 log::info!("expired: {} {}", peer, addr);
@@ -323,9 +321,7 @@ where
             true
         });
         if !expired.is_empty() {
-            let event = Event::Expired(ExpiredAddrsIter {
-                inner: expired.into_iter(),
-            });
+            let event = Event::Expired(expired);
             return Poll::Ready(ToSwarm::GenerateEvent(event));
         }
         if let Some(closest_expiration) = closest_expiration {
@@ -342,67 +338,11 @@ where
 #[derive(Debug, Clone)]
 pub enum Event {
     /// Discovered nodes through mDNS.
-    Discovered(DiscoveredAddrsIter),
+    Discovered(Vec<(PeerId, Multiaddr)>),
 
     /// The given combinations of `PeerId` and `Multiaddr` have expired.
     ///
     /// Each discovered record has a time-to-live. When this TTL expires and the address hasn't
     /// been refreshed, we remove it from the list and emit it as an `Expired` event.
-    Expired(ExpiredAddrsIter),
-}
-
-/// Iterator that produces the list of addresses that have been discovered.
-#[derive(Clone)]
-pub struct DiscoveredAddrsIter {
-    inner: smallvec::IntoIter<[(PeerId, Multiaddr); 4]>,
-}
-
-impl Iterator for DiscoveredAddrsIter {
-    type Item = (PeerId, Multiaddr);
-
-    #[inline]
-    fn next(&mut self) -> Option<Self::Item> {
-        self.inner.next()
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.inner.size_hint()
-    }
-}
-
-impl ExactSizeIterator for DiscoveredAddrsIter {}
-
-impl fmt::Debug for DiscoveredAddrsIter {
-    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt.debug_struct("DiscoveredAddrsIter").finish()
-    }
-}
-
-/// Iterator that produces the list of addresses that have expired.
-#[derive(Clone)]
-pub struct ExpiredAddrsIter {
-    inner: smallvec::IntoIter<[(PeerId, Multiaddr); 4]>,
-}
-
-impl Iterator for ExpiredAddrsIter {
-    type Item = (PeerId, Multiaddr);
-
-    #[inline]
-    fn next(&mut self) -> Option<Self::Item> {
-        self.inner.next()
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.inner.size_hint()
-    }
-}
-
-impl ExactSizeIterator for ExpiredAddrsIter {}
-
-impl fmt::Debug for ExpiredAddrsIter {
-    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt.debug_struct("ExpiredAddrsIter").finish()
-    }
+    Expired(Vec<(PeerId, Multiaddr)>),
 }

protocols/mdns/tests/use-async-std.rs

@@ -61,13 +61,13 @@ async fn test_expired_async_std() {
 
     loop {
         match futures::future::select(a.next_behaviour_event(), b.next_behaviour_event()).await {
-            Either::Left((Event::Expired(mut peers), _)) => {
-                if peers.any(|(p, _)| p == b_peer_id) {
+            Either::Left((Event::Expired(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == b_peer_id) {
                     return;
                 }
             }
-            Either::Right((Event::Expired(mut peers), _)) => {
-                if peers.any(|(p, _)| p == a_peer_id) {
+            Either::Right((Event::Expired(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == a_peer_id) {
                     return;
                 }
             }
@@ -93,8 +93,8 @@ async fn test_no_expiration_on_close_async_std() {
 
     // 1. Connect via address from mDNS event
     loop {
-        if let Event::Discovered(mut peers) = a.next_behaviour_event().await {
-            if let Some((_, addr)) = peers.find(|(p, _)| p == &b_peer_id) {
+        if let Event::Discovered(peers) = a.next_behaviour_event().await {
+            if let Some((_, addr)) = peers.into_iter().find(|(p, _)| p == &b_peer_id) {
                 a.dial_and_wait(addr).await;
                 break;
             }
@@ -130,13 +130,13 @@ async fn run_discovery_test(config: Config) {
 
     while !discovered_a && !discovered_b {
         match futures::future::select(a.next_behaviour_event(), b.next_behaviour_event()).await {
-            Either::Left((Event::Discovered(mut peers), _)) => {
-                if peers.any(|(p, _)| p == b_peer_id) {
+            Either::Left((Event::Discovered(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == b_peer_id) {
                     discovered_b = true;
                 }
             }
-            Either::Right((Event::Discovered(mut peers), _)) => {
-                if peers.any(|(p, _)| p == a_peer_id) {
+            Either::Right((Event::Discovered(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == a_peer_id) {
                     discovered_a = true;
                 }
             }

protocols/mdns/tests/use-tokio.rs

@@ -59,13 +59,13 @@ async fn test_expired_tokio() {
 
     loop {
         match futures::future::select(a.next_behaviour_event(), b.next_behaviour_event()).await {
-            Either::Left((Event::Expired(mut peers), _)) => {
-                if peers.any(|(p, _)| p == b_peer_id) {
+            Either::Left((Event::Expired(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == b_peer_id) {
                     return;
                 }
             }
-            Either::Right((Event::Expired(mut peers), _)) => {
-                if peers.any(|(p, _)| p == a_peer_id) {
+            Either::Right((Event::Expired(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == a_peer_id) {
                     return;
                 }
             }
@@ -86,13 +86,13 @@ async fn run_discovery_test(config: Config) {
 
     while !discovered_a && !discovered_b {
         match futures::future::select(a.next_behaviour_event(), b.next_behaviour_event()).await {
-            Either::Left((Event::Discovered(mut peers), _)) => {
-                if peers.any(|(p, _)| p == b_peer_id) {
+            Either::Left((Event::Discovered(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == b_peer_id) {
                     discovered_b = true;
                 }
             }
-            Either::Right((Event::Discovered(mut peers), _)) => {
-                if peers.any(|(p, _)| p == a_peer_id) {
+            Either::Right((Event::Discovered(peers), _)) => {
+                if peers.into_iter().any(|(p, _)| p == a_peer_id) {
                     discovered_a = true;
                 }
             }