feat: async header transform

crates/net/network/src/config.rs

@@ -99,7 +99,7 @@ pub struct NetworkConfig<C, N: NetworkPrimitives = EthNetworkPrimitives> {
     /// If non-empty, peers that don't have these blocks will be filtered out.
     pub required_block_hashes: Vec<B256>,
     /// A transformation hook applied to the downloaded headers.
-    pub header_transform: Box<dyn HeaderTransform<N::BlockHeader>>,
+    pub header_transform: Arc<dyn HeaderTransform<N::BlockHeader>>,
 }
 
 // === impl NetworkConfig ===
@@ -232,7 +232,7 @@ pub struct NetworkConfigBuilder<N: NetworkPrimitives = EthNetworkPrimitives> {
     /// Optional network id
     network_id: Option<u64>,
     /// The header transform type.
-    header_transform: Option<Box<dyn HeaderTransform<N::BlockHeader>>>,
+    header_transform: Option<Arc<dyn HeaderTransform<N::BlockHeader>>>,
 }
 
 impl NetworkConfigBuilder<EthNetworkPrimitives> {
@@ -605,7 +605,7 @@ impl<N: NetworkPrimitives> NetworkConfigBuilder<N> {
     /// Sets the header transform type.
     pub fn header_transform(
         mut self,
-        header_transform: Box<dyn HeaderTransform<N::BlockHeader>>,
+        header_transform: Arc<dyn HeaderTransform<N::BlockHeader>>,
     ) -> Self {
         self.header_transform = Some(header_transform);
         self
@@ -717,7 +717,7 @@ impl<N: NetworkPrimitives> NetworkConfigBuilder<N> {
             nat,
             handshake,
             required_block_hashes,
-            header_transform: header_transform.unwrap_or_else(|| Box::new(())),
+            header_transform: header_transform.unwrap_or_else(|| Arc::new(())),
         }
     }
 }

crates/net/network/src/fetch/mod.rs

@@ -56,7 +56,7 @@ pub struct StateFetcher<N: NetworkPrimitives = EthNetworkPrimitives> {
     /// Sender for download requests, used to detach a [`FetchClient`]
     download_requests_tx: UnboundedSender<DownloadRequest<N>>,
     /// A transformation hook applied to the downloaded headers.
-    header_transform: Box<dyn HeaderTransform<N::BlockHeader>>,
+    header_transform: Arc<dyn HeaderTransform<N::BlockHeader>>,
 }
 
 // === impl StateSyncer ===
@@ -65,7 +65,7 @@ impl<N: NetworkPrimitives> StateFetcher<N> {
     pub(crate) fn new(
         peers_handle: PeersHandle,
         num_active_peers: Arc<AtomicUsize>,
-        header_transform: Box<dyn HeaderTransform<N::BlockHeader>>,
+        header_transform: Arc<dyn HeaderTransform<N::BlockHeader>>,
     ) -> Self {
         let (download_requests_tx, download_requests_rx) = mpsc::unbounded_channel();
         Self {
@@ -279,10 +279,15 @@ impl<N: NetworkPrimitives> StateFetcher<N> {
             resp.as_ref().is_some_and(|r| res.is_likely_bad_headers_response(&r.request));
 
         if let Some(resp) = resp {
-            // apply the header transform and delegate the response
-            let _ = resp.response.send(res.map(|h| {
-                (peer_id, h.into_iter().map(|h| self.header_transform.map(h)).collect()).into()
-            }));
+            let header_transform = self.header_transform.clone();
+            tokio::spawn(async move {
+                let res = match res {
+                    Ok(headers) => Ok(header_transform.map(headers).await),
+                    Err(e) => Err(e),
+                };
+
+                let _ = resp.response.send(res.map(|h| (peer_id, h).into()));
+            });
         }
 
         if let Some(peer) = self.peers.get_mut(&peer_id) {
@@ -496,7 +501,7 @@ mod tests {
         let mut fetcher = StateFetcher::<EthNetworkPrimitives>::new(
             manager.handle(),
             Default::default(),
-            Box::new(()),
+            Arc::new(()),
         );
 
         poll_fn(move |cx| {
@@ -521,7 +526,7 @@ mod tests {
         let mut fetcher = StateFetcher::<EthNetworkPrimitives>::new(
             manager.handle(),
             Default::default(),
-            Box::new(()),
+            Arc::new(()),
         );
         // Add a few random peers
         let peer1 = B512::random();
@@ -548,7 +553,7 @@ mod tests {
         let mut fetcher = StateFetcher::<EthNetworkPrimitives>::new(
             manager.handle(),
             Default::default(),
-            Box::new(()),
+            Arc::new(()),
         );
         // Add a few random peers
         let peer1 = B512::random();
@@ -577,7 +582,7 @@ mod tests {
         let mut fetcher = StateFetcher::<EthNetworkPrimitives>::new(
             manager.handle(),
             Default::default(),
-            Box::new(()),
+            Arc::new(()),
         );
         let peer_id = B512::random();
 
@@ -611,7 +616,7 @@ mod tests {
         let mut fetcher = StateFetcher::<EthNetworkPrimitives>::new(
             manager.handle(),
             Default::default(),
-            Box::new(()),
+            Arc::new(()),
         );
         let peer_id = B512::random();
 

crates/net/network/src/state.rs

@@ -102,7 +102,7 @@ impl<N: NetworkPrimitives> NetworkState<N> {
         discovery: Discovery,
         peers_manager: PeersManager,
         num_active_peers: Arc<AtomicUsize>,
-        header_transform: Box<dyn HeaderTransform<N::BlockHeader>>,
+        header_transform: Arc<dyn HeaderTransform<N::BlockHeader>>,
     ) -> Self {
         let state_fetcher =
             StateFetcher::new(peers_manager.handle(), num_active_peers, header_transform);
@@ -582,7 +582,7 @@ mod tests {
             queued_messages: Default::default(),
             client: BlockNumReader(Box::new(NoopProvider::default())),
             discovery: Discovery::noop(),
-            state_fetcher: StateFetcher::new(handle, Default::default(), Box::new(())),
+            state_fetcher: StateFetcher::new(handle, Default::default(), Arc::new(())),
         }
     }
 

crates/net/network/src/transform/header.rs

@@ -2,15 +2,17 @@
 
 use reth_primitives_traits::BlockHeader;
 
-/// An instance of the trait applies a mapping to the input header.
+/// An instance of the trait applies a mapping to the input headers.
+#[async_trait::async_trait]
 pub trait HeaderTransform<H: BlockHeader>: std::fmt::Debug + Send + Sync {
-    /// Applies a mapping to the input header.
-    fn map(&self, header: H) -> H;
+    /// Applies a mapping to the input headers.
+    async fn map(&self, headers: Vec<H>) -> Vec<H>;
 }
 
+#[async_trait::async_trait]
 impl<H: BlockHeader> HeaderTransform<H> for () {
-    fn map(&self, header: H) -> H {
-        header
+    async fn map(&self, headers: Vec<H>) -> Vec<H> {
+        headers
     }
 }