recompute neighbours whenever topology changes

1 files changed, 20 insertions, 0 deletions

diff --git a/src/swarm/topology.rs b/src/swarm/topology.rs
index 57856b6..b40b120 100644
--- a/src/swarm/topology.rs
+++ b/src/swarm/topology.rs
@@ -107,6 +107,26 @@ pub(crate) struct NeighbourChange {
     pub(crate) removed: Vec<String>,
 }
 
+/// Recomputes the neighbours whenever something they depend on may have changed
+/// (`AppState::topology_changed`): the member list (`swarm::sync::run_change_publisher`),
+/// a peer becoming unreachable or reachable again (`swarm::peer`), and every 5 s as a
+/// fallback, which also covers unreachability expiring after `dormant_probe`. A burst of
+/// notifications coalesces into one recomputation.
+pub(crate) async fn run_worker(state: AppState) {
+    loop {
+        state.topology_changed.notified().await;
+        if let Some(change) = refresh(&state).await {
+            crate::swarm::peer::apply_neighbour_change(&state, change).await;
+        }
+    }
+}
+
+/// Whether a change at `path` may change the neighbours: one in the member list, or the
+/// root (the whole document replaced, as after an epoch switch).
+pub(crate) fn affects_neighbours(path: &[String]) -> bool {
+    path.is_empty() || path.starts_with(&members::members_dir())
+}
+
 /// Recomputes the neighbours once ready, if the member list, the reachable members or
 /// `k` changed.
 pub(crate) async fn refresh(state: &AppState) -> Option<NeighbourChange> {