links member from the view

2 files changed, 20 insertions, 5 deletions

diff --git a/src/swarm/links.rs b/src/swarm/links.rs
index 2d9071b..ea5564e 100644
--- a/src/swarm/links.rs
+++ b/src/swarm/links.rs
@@ -616,11 +616,16 @@ pub(crate) async fn unsubscribe(state: &AppState, member: &str) {
 
 /// A LINKS from `peer`: answered if it's a member, and not answered lately.
 pub(crate) async fn answer(state: &AppState, peer: &str, request: LinksRequest) {
-    let member = {
-        let replica = state.doc.read().await;
-        members::members(&replica.doc)
-            .iter()
-            .any(|member| member == peer)
+    // From the neighbours' view, kept as the member list changes: no document read per
+    // request.
+    let member = match crate::swarm::topology::listed(state, peer) {
+        Some(listed) => listed,
+        None => {
+            let replica = state.doc.read().await;
+            members::members(&replica.doc)
+                .iter()
+                .any(|member| member == peer)
+        }
     };
     if !member {
         debug!(peer = %peer, "Not answering LINKS from a peer that isn't a member");
diff --git a/src/swarm/topology/mod.rs b/src/swarm/topology/mod.rs
index 179cf83..b001809 100644
--- a/src/swarm/topology/mod.rs
+++ b/src/swarm/topology/mod.rs
@@ -100,6 +100,16 @@ pub(crate) fn member_list_graph(
     })))
 }
 
+/// Whether `peer` is in the member list, as the view was last computed from it; None
+/// while the view isn't known.
+pub(crate) fn listed(state: &AppState, peer: &str) -> Option<bool> {
+    state
+        .neighbours
+        .read_or_recover()
+        .as_ref()
+        .map(|view| view.members.iter().any(|member| member == peer))
+}
+
 /// Whether the neighbours are computed from the member list yet (before, everyone
 /// counts as a neighbour).
 pub(crate) fn view_known(state: &AppState) -> bool {