From 89328614579a7270c09729dcfc20e3470529eaa3 Mon Sep 17 00:00:00 2001
From: Yiannis Marangos <yiannis@eiger.co>
Date: Thu, 25 Jan 2024 16:38:12 +0200
Subject: [PATCH] fix: Do not reset peer state on new established connection

libp2p may establish multiple connections at the same time
to a peer and we shouldn't reset the state.
---
 src/client.rs | 34 +++++++++++++++++++++++++---------
 src/lib.rs    | 10 +++++++++-
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/src/client.rs b/src/client.rs
index 1bb4770..43d2d39 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -1,4 +1,4 @@
-use std::collections::VecDeque;
+use std::collections::{hash_map, VecDeque};
 use std::fmt;
 use std::sync::Arc;
 use std::task::{ready, Context, Poll};
@@ -81,6 +81,7 @@ where
 
 #[derive(Debug)]
 struct PeerState<const S: usize> {
+    established_connections_num: usize,
     sending: Arc<Mutex<SendingState>>,
     wantlist: WantlistState<S>,
     send_full: bool,
@@ -124,14 +125,19 @@ where
     }
 
     pub(crate) fn new_connection_handler(&mut self, peer: PeerId) -> ClientConnectionHandler<S> {
-        self.peers.insert(
-            peer,
-            PeerState {
-                sending: Arc::new(Mutex::new(SendingState::Ready)),
-                wantlist: WantlistState::new(),
-                send_full: true,
-            },
-        );
+        match self.peers.entry(peer) {
+            hash_map::Entry::Occupied(mut entry) => {
+                entry.get_mut().established_connections_num += 1;
+            }
+            hash_map::Entry::Vacant(entry) => {
+                entry.insert(PeerState {
+                    established_connections_num: 1,
+                    sending: Arc::new(Mutex::new(SendingState::Ready)),
+                    wantlist: WantlistState::new(),
+                    send_full: true,
+                });
+            }
+        }
 
         ClientConnectionHandler {
             protocol: self.protocol.clone(),
@@ -143,6 +149,16 @@ where
         }
     }
 
+    pub(crate) fn on_connection_closed(&mut self, peer: PeerId) {
+        if let hash_map::Entry::Occupied(mut entry) = self.peers.entry(peer) {
+            entry.get_mut().established_connections_num -= 1;
+
+            if entry.get_mut().established_connections_num == 0 {
+                entry.remove();
+            }
+        }
+    }
+
     fn next_query_id(&mut self) -> BitswapQueryId {
         let id = BitswapQueryId(self.next_query_id);
         self.next_query_id += 1;
diff --git a/src/lib.rs b/src/lib.rs
index f5aeb9b..88d3784 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,6 +8,7 @@ use blockstore::{Blockstore, BlockstoreError};
 use cid::CidGeneric;
 use client::SendingState;
 use futures::{stream::SelectAll, StreamExt};
+use libp2p::swarm::ConnectionClosed;
 use libp2p::{
     core::{upgrade::ReadyUpgrade, Endpoint},
     swarm::{
@@ -127,7 +128,14 @@ where
         })
     }
 
-    fn on_swarm_event(&mut self, _event: FromSwarm) {}
+    fn on_swarm_event(&mut self, event: FromSwarm) {
+        match event {
+            FromSwarm::ConnectionClosed(ConnectionClosed { peer_id, .. }) => {
+                self.client.on_connection_closed(peer_id);
+            }
+            _ => {}
+        }
+    }
 
     fn on_connection_handler_event(
         &mut self,