Introduce helper function for mapping RequestResponseEvent

Decomposing a RequestResponseEvent is quite verbose. We can introduce
a helper function that does the matching for us and delegates to
specific `From` implementations for the protocol specific bits.

swap/src/network/quote.rs

@@ -3,6 +3,7 @@ use crate::network::request_response::CborCodec;
 use libp2p::core::ProtocolName;
 use libp2p::request_response::{
     ProtocolSupport, RequestResponse, RequestResponseConfig, RequestResponseEvent,
+    RequestResponseMessage,
 };
 use serde::{Deserialize, Serialize};
 
@@ -17,6 +18,8 @@ impl ProtocolName for BidQuoteProtocol {
     }
 }
 
+pub type Message = RequestResponseMessage<(), BidQuote>;
+
 /// Represents a quote for buying XMR.
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct BidQuote {

swap/src/network/spot_price.rs

@@ -3,6 +3,7 @@ use crate::{bitcoin, monero};
 use libp2p::core::ProtocolName;
 use libp2p::request_response::{
     ProtocolSupport, RequestResponse, RequestResponseConfig, RequestResponseEvent,
+    RequestResponseMessage,
 };
 use serde::{Deserialize, Serialize};
 
@@ -39,6 +40,8 @@ pub struct Response {
 
 pub type Behaviour = RequestResponse<CborCodec<SpotPriceProtocol, Request, Response>>;
 
+pub type Message = RequestResponseMessage<Request, Response>;
+
 /// Constructs a new instance of the `spot-price` behaviour to be used by Alice.
 ///
 /// Alice only supports inbound connections, i.e. providing spot prices for BTC

swap/src/protocol/alice/behaviour.rs

@@ -7,7 +7,7 @@ use crate::protocol::alice::{
 use crate::protocol::bob::EncryptedSignature;
 use crate::{bitcoin, monero};
 use anyhow::{anyhow, Error, Result};
-use libp2p::request_response::{RequestResponseMessage, ResponseChannel};
+use libp2p::request_response::{RequestResponseEvent, RequestResponseMessage, ResponseChannel};
 use libp2p::{NetworkBehaviour, PeerId};
 use rand::{CryptoRng, RngCore};
 use tracing::debug;
@@ -16,7 +16,7 @@ use tracing::debug;
 pub enum OutEvent {
     ConnectionEstablished(PeerId),
     SpotPriceRequested {
-        msg: spot_price::Request,
+        request: spot_price::Request,
         channel: ResponseChannel<spot_price::Response>,
         peer: PeerId,
     },
@@ -51,63 +51,69 @@ impl From<peer_tracker::OutEvent> for OutEvent {
     }
 }
 
+impl OutEvent {
+    fn unexpected_response(peer: PeerId) -> OutEvent {
+        OutEvent::Failure {
+            peer,
+            error: anyhow!("Unexpected response received"),
+        }
+    }
+}
+
+impl From<(PeerId, quote::Message)> for OutEvent {
+    fn from((peer, message): (PeerId, quote::Message)) -> Self {
+        match message {
+            quote::Message::Request { channel, .. } => OutEvent::QuoteRequested { channel, peer },
+            quote::Message::Response { .. } => OutEvent::unexpected_response(peer),
+        }
+    }
+}
+
+impl From<(PeerId, spot_price::Message)> for OutEvent {
+    fn from((peer, message): (PeerId, spot_price::Message)) -> Self {
+        match message {
+            spot_price::Message::Request {
+                request, channel, ..
+            } => OutEvent::SpotPriceRequested {
+                request,
+                channel,
+                peer,
+            },
+            spot_price::Message::Response { .. } => OutEvent::unexpected_response(peer),
+        }
+    }
+}
+
 impl From<spot_price::OutEvent> for OutEvent {
     fn from(event: spot_price::OutEvent) -> Self {
-        match event {
+        map_rr_event_to_outevent(event)
-            spot_price::OutEvent::Message {
-                peer,
-                message:
-                    RequestResponseMessage::Request {
-                        channel,
-                        request: msg,
-                        ..
-                    },
-            } => OutEvent::SpotPriceRequested { msg, channel, peer },
-            spot_price::OutEvent::Message {
-                message: RequestResponseMessage::Response { .. },
-                peer,
-            } => OutEvent::Failure {
-                error: anyhow!("Alice is only meant to hand out spot prices, not receive them"),
-                peer,
-            },
-            spot_price::OutEvent::ResponseSent { .. } => OutEvent::ResponseSent,
-            spot_price::OutEvent::InboundFailure { peer, error, .. } => OutEvent::Failure {
-                error: anyhow!("spot_price protocol failed due to {:?}", error),
-                peer,
-            },
-            spot_price::OutEvent::OutboundFailure { peer, error, .. } => OutEvent::Failure {
-                error: anyhow!("spot_price protocol failed due to {:?}", error),
-                peer,
-            },
-        }
     }
 }
 
 impl From<quote::OutEvent> for OutEvent {
     fn from(event: quote::OutEvent) -> Self {
-        match event {
+        map_rr_event_to_outevent(event)
-            quote::OutEvent::Message {
-                peer,
-                message: RequestResponseMessage::Request { channel, .. },
-            } => OutEvent::QuoteRequested { channel, peer },
-            quote::OutEvent::Message {
-                message: RequestResponseMessage::Response { .. },
-                peer,
-            } => OutEvent::Failure {
-                error: anyhow!("Alice is only meant to hand out quotes, not receive them"),
-                peer,
-            },
-            quote::OutEvent::ResponseSent { .. } => OutEvent::ResponseSent,
-            quote::OutEvent::InboundFailure { peer, error, .. } => OutEvent::Failure {
-                error: anyhow!("quote protocol failed due to {:?}", error),
-                peer,
-            },
-            quote::OutEvent::OutboundFailure { peer, error, .. } => OutEvent::Failure {
-                error: anyhow!("quote protocol failed due to {:?}", error),
-                peer,
-            },
     }
 }
+
+fn map_rr_event_to_outevent<I, O>(event: RequestResponseEvent<I, O>) -> OutEvent
+where
+    OutEvent: From<(PeerId, RequestResponseMessage<I, O>)>,
+{
+    use RequestResponseEvent::*;
+
+    match event {
+        Message { message, peer, .. } => OutEvent::from((peer, message)),
+        ResponseSent { .. } => OutEvent::ResponseSent,
+        InboundFailure { peer, error, .. } => OutEvent::Failure {
+            error: anyhow!("protocol failed due to {:?}", error),
+            peer,
+        },
+        OutboundFailure { peer, error, .. } => OutEvent::Failure {
+            error: anyhow!("protocol failed due to {:?}", error),
+            peer,
+        },
+    }
 }
 
 impl From<execution_setup::OutEvent> for OutEvent {

swap/src/protocol/alice/event_loop.rs

@@ -105,8 +105,8 @@ where
                         OutEvent::ConnectionEstablished(alice) => {
                             debug!("Connection Established with {}", alice);
                         }
-                        OutEvent::SpotPriceRequested { msg, channel, peer } => {
+                        OutEvent::SpotPriceRequested { request, channel, peer } => {
-                            let btc = msg.btc;
+                            let btc = request.btc;
                             let xmr = match self.handle_spot_price_request(btc, self.monero_wallet.clone()).await {
                                 Ok(xmr) => xmr,
                                 Err(e) => {

swap/src/protocol/bob.rs

@@ -7,7 +7,7 @@ use crate::{bitcoin, monero};
 use anyhow::{anyhow, Error, Result};
 pub use execution_setup::{Message0, Message2, Message4};
 use libp2p::core::Multiaddr;
-use libp2p::request_response::{RequestResponseMessage, ResponseChannel};
+use libp2p::request_response::{RequestResponseEvent, RequestResponseMessage, ResponseChannel};
 use libp2p::{NetworkBehaviour, PeerId};
 use std::sync::Arc;
 use tracing::debug;
@@ -126,6 +126,30 @@ pub enum OutEvent {
     CommunicationError(Error),
 }
 
+impl OutEvent {
+    fn unexpected_request() -> OutEvent {
+        OutEvent::CommunicationError(anyhow!("Unexpected request received"))
+    }
+}
+
+impl From<quote::Message> for OutEvent {
+    fn from(message: quote::Message) -> Self {
+        match message {
+            quote::Message::Request { .. } => OutEvent::unexpected_request(),
+            quote::Message::Response { response, .. } => OutEvent::QuoteReceived(response),
+        }
+    }
+}
+
+impl From<spot_price::Message> for OutEvent {
+    fn from(message: spot_price::Message) -> Self {
+        match message {
+            spot_price::Message::Request { .. } => OutEvent::unexpected_request(),
+            spot_price::Message::Response { response, .. } => OutEvent::SpotPriceReceived(response),
+        }
+    }
+}
+
 impl From<peer_tracker::OutEvent> for OutEvent {
     fn from(event: peer_tracker::OutEvent) -> Self {
         match event {
@@ -138,65 +162,35 @@ impl From<peer_tracker::OutEvent> for OutEvent {
 
 impl From<spot_price::OutEvent> for OutEvent {
     fn from(event: spot_price::OutEvent) -> Self {
-        match event {
+        map_rr_event_to_outevent(event)
-            spot_price::OutEvent::Message {
-                message: RequestResponseMessage::Response { response, .. },
-                ..
-            } => OutEvent::SpotPriceReceived(response),
-            spot_price::OutEvent::Message {
-                message: RequestResponseMessage::Request { .. },
-                ..
-            } => OutEvent::CommunicationError(anyhow!(
-                "Bob is only meant to receive spot prices, not hand them out"
-            )),
-            spot_price::OutEvent::ResponseSent { .. } => OutEvent::ResponseSent,
-            spot_price::OutEvent::InboundFailure { peer, error, .. } => {
-                OutEvent::CommunicationError(anyhow!(
-                    "spot_price protocol with peer {} failed due to {:?}",
-                    peer,
-                    error
-                ))
-            }
-            spot_price::OutEvent::OutboundFailure { peer, error, .. } => {
-                OutEvent::CommunicationError(anyhow!(
-                    "spot_price protocol with peer {} failed due to {:?}",
-                    peer,
-                    error
-                ))
-            }
-        }
     }
 }
 
 impl From<quote::OutEvent> for OutEvent {
     fn from(event: quote::OutEvent) -> Self {
+        map_rr_event_to_outevent(event)
+    }
+}
+
+fn map_rr_event_to_outevent<I, O>(event: RequestResponseEvent<I, O>) -> OutEvent
+where
+    OutEvent: From<RequestResponseMessage<I, O>>,
+{
+    use RequestResponseEvent::*;
+
     match event {
-            quote::OutEvent::Message {
+        Message { message, .. } => OutEvent::from(message),
-                message: RequestResponseMessage::Response { response, .. },
+        ResponseSent { .. } => OutEvent::ResponseSent,
-                ..
+        InboundFailure { peer, error, .. } => OutEvent::CommunicationError(anyhow!(
-            } => OutEvent::QuoteReceived(response),
+            "protocol with peer {} failed due to {:?}",
-            quote::OutEvent::Message {
+            peer,
-                message: RequestResponseMessage::Request { .. },
+            error
-                ..
-            } => OutEvent::CommunicationError(anyhow!(
-                "Bob is only meant to receive quotes, not hand them out"
         )),
-            quote::OutEvent::ResponseSent { .. } => OutEvent::ResponseSent,
+        OutboundFailure { peer, error, .. } => OutEvent::CommunicationError(anyhow!(
-            quote::OutEvent::InboundFailure { peer, error, .. } => {
+            "protocol with peer {} failed due to {:?}",
-                OutEvent::CommunicationError(anyhow!(
-                    "quote protocol with peer {} failed due to {:?}",
             peer,
             error
-                ))
+        )),
-            }
-            quote::OutEvent::OutboundFailure { peer, error, .. } => {
-                OutEvent::CommunicationError(anyhow!(
-                    "quote protocol with peer {} failed due to {:?}",
-                    peer,
-                    error
-                ))
-            }
-        }
     }
 }