delta end guarded

1 files changed, 23 insertions, 7 deletions

diff --git a/src/swarm/sync.rs b/src/swarm/sync.rs
index 5819bb7..a4ad30c 100644
--- a/src/swarm/sync.rs
+++ b/src/swarm/sync.rs
@@ -722,14 +722,12 @@ fn fetch_delta(state: &AppState, peer: &str, epoch: transport::Epoch, spec: tran
     let state = state.clone();
     let peer = peer.to_owned();
     tokio::spawn(async move {
+        let done = DeltaDone {
+            state: state.clone(),
+            peer: peer.clone(),
+        };
         let applied = download_and_apply_delta(&state, &peer, epoch, spec).await;
-        // Those that offered meanwhile send what is still missing: our next message
-        // says what we have now.
-        for other in state.blobs.end_delta(&peer) {
-            if other != peer {
-                state.request_sync(&other);
-            }
-        }
+        drop(done);
         match applied {
             Ok(changed) => {
                 state.notify_store_changed();
@@ -746,6 +744,24 @@ fn fetch_delta(state: &AppState, peer: &str, epoch: transport::Epoch, spec: tran
     });
 }
 
+/// The delta download from `peer` ended, when dropped: however it ended, a panic
+/// included, the next may start (`Blobs::end_delta`), and those that offered meanwhile
+/// send what is still missing (our next message says what we have now).
+struct DeltaDone {
+    state: AppState,
+    peer: String,
+}
+
+impl Drop for DeltaDone {
+    fn drop(&mut self) {
+        for other in self.state.blobs.end_delta(&self.peer) {
+            if other != self.peer {
+                self.state.request_sync(&other);
+            }
+        }
+    }
+}
+
 /// Returns whether our heads changed.
 async fn download_and_apply_delta(
     state: &AppState,