refactor(swarm)!: remove handler from NetworkBehaviourAction::Dial (libp2p#3328)

We create the `ConnectionId` for the new connection as part of `DialOpts`. This allows `NetworkBehaviour`s to accurately track state regarding their own dial attempts.

This patch is the main enabler of libp2p#3254. Removing the `handler` field will allow us to deprecate the `NetworkBehaviour::new_handler` function in favor of four new ones that give more control over the connection lifecycle.

Author: thomaseizinger

src/behaviour.rs

@@ -38,7 +38,7 @@ use libp2p_swarm::{
         ExpiredListenAddr, FromSwarm,
     },
     ConnectionId, ExternalAddresses, ListenAddresses, NetworkBehaviour, NetworkBehaviourAction,
-    PollParameters, THandlerOutEvent,
+    PollParameters, THandlerInEvent, THandlerOutEvent,
 };
 use std::{
     collections::{HashMap, VecDeque},
@@ -208,10 +208,7 @@ pub struct Behaviour {
     last_probe: Option<Instant>,
 
     pending_actions: VecDeque<
-        NetworkBehaviourAction<
-            <Self as NetworkBehaviour>::OutEvent,
-            <Self as NetworkBehaviour>::ConnectionHandler,
-        >,
+        NetworkBehaviourAction<<Self as NetworkBehaviour>::OutEvent, THandlerInEvent<Self>>,
     >,
 
     probe_id: ProbeId,
@@ -389,14 +386,14 @@ impl Behaviour {
         &mut self,
         DialFailure {
             peer_id,
-            handler,
+            connection_id,
             error,
-        }: DialFailure<<Self as NetworkBehaviour>::ConnectionHandler>,
+        }: DialFailure,
     ) {
         self.inner
             .on_swarm_event(FromSwarm::DialFailure(DialFailure {
                 peer_id,
-                handler,
+                connection_id,
                 error,
             }));
         if let Some(event) = self.as_server().on_outbound_dial_error(peer_id, error) {
@@ -560,10 +557,8 @@ impl NetworkBehaviour for Behaviour {
     }
 }
 
-type Action = NetworkBehaviourAction<
-    <Behaviour as NetworkBehaviour>::OutEvent,
-    <Behaviour as NetworkBehaviour>::ConnectionHandler,
->;
+type Action =
+    NetworkBehaviourAction<<Behaviour as NetworkBehaviour>::OutEvent, THandlerInEvent<Behaviour>>;
 
 // Trait implemented for `AsClient` and `AsServer` to handle events from the inner [`request_response::Behaviour`] Protocol.
 trait HandleInnerEvent {

src/behaviour/as_server.rs

@@ -29,7 +29,7 @@ use libp2p_request_response::{
 };
 use libp2p_swarm::{
     dial_opts::{DialOpts, PeerCondition},
-    ConnectionId, DialError, NetworkBehaviour, NetworkBehaviourAction, PollParameters,
+    ConnectionId, DialError, NetworkBehaviourAction, PollParameters,
 };
 use std::{
     collections::{HashMap, HashSet, VecDeque},
@@ -138,7 +138,6 @@ impl<'a> HandleInnerEvent for AsServer<'a> {
                                     )
                                     .addresses(addrs)
                                     .build(),
-                                handler: self.inner.new_handler(),
                             },
                         ])
                     }