Decouple Bob's EventLoop from the builder

Instead of instantiating the `EventLoop` within the builder, we only
pass in the necessary arguments (which is the `EventLoopHandle`) to
the Builder upon `new`.

This is work towards #255 which will require us to perform network
communication (which implies having the `EventLoop`) before starting
a swap.

swap/src/bin/swap_cli.rs

@@ -31,7 +31,7 @@ use swap::{
     monero::{CreateWallet, OpenWallet},
     protocol::{
         bob,
-        bob::{cancel::CancelError, Builder},
+        bob::{cancel::CancelError, Builder, EventLoop},
     },
     seed::Seed,
 };
@@ -111,6 +111,7 @@ async fn main() -> Result<()> {
                 init_bitcoin_wallet(config, bitcoin_network, &wallet_data_dir, seed).await?;
             let monero_wallet =
                 init_monero_wallet(monero_network, monero_wallet_rpc_process.endpoint()).await?;
+            let bitcoin_wallet = Arc::new(bitcoin_wallet);
 
             let swap_id = Uuid::new_v4();
 
@@ -137,19 +138,25 @@ async fn main() -> Result<()> {
 
             let send_bitcoin = bitcoin_wallet.max_giveable(TxLock::script_size()).await?;
 
-            let bob_factory = Builder::new(
-                seed,
+            let (event_loop, event_loop_handle) = EventLoop::new(
+                &seed.derive_libp2p_identity(),
+                alice_peer_id,
+                alice_addr,
+                bitcoin_wallet.clone(),
+            )?;
+            let handle = tokio::spawn(event_loop.run());
+
+            let swap = Builder::new(
                 db,
                 swap_id,
-                Arc::new(bitcoin_wallet),
+                bitcoin_wallet.clone(),
                 Arc::new(monero_wallet),
-                alice_addr,
-                alice_peer_id,
                 execution_params,
-            );
-            let (swap, event_loop) = bob_factory.with_init_params(send_bitcoin).build().await?;
+                event_loop_handle,
+            )
+            .with_init_params(send_bitcoin)
+            .build()?;
 
-            let handle = tokio::spawn(event_loop.run());
             let swap = bob::run(swap);
             tokio::select! {
                 event_loop_result = handle => {
@@ -181,19 +188,26 @@ async fn main() -> Result<()> {
                 init_bitcoin_wallet(config, bitcoin_network, &wallet_data_dir, seed).await?;
             let monero_wallet =
                 init_monero_wallet(monero_network, monero_wallet_rpc_process.endpoint()).await?;
+            let bitcoin_wallet = Arc::new(bitcoin_wallet);
 
-            let bob_factory = Builder::new(
-                seed,
+            let (event_loop, event_loop_handle) = EventLoop::new(
+                &seed.derive_libp2p_identity(),
+                alice_peer_id,
+                alice_addr,
+                bitcoin_wallet.clone(),
+            )?;
+            let handle = tokio::spawn(event_loop.run());
+
+            let swap = Builder::new(
                 db,
                 swap_id,
-                Arc::new(bitcoin_wallet),
+                bitcoin_wallet.clone(),
                 Arc::new(monero_wallet),
-                alice_addr,
-                alice_peer_id,
                 execution_params,
-            );
-            let (swap, event_loop) = bob_factory.build().await?;
-            let handle = tokio::spawn(event_loop.run());
+                event_loop_handle,
+            )
+            .build()?;
+
             let swap = bob::run(swap);
             tokio::select! {
                 event_loop_result = handle => {

swap/src/protocol/bob.rs

@@ -7,10 +7,9 @@ use crate::{
     monero,
     network::peer_tracker::{self, PeerTracker},
     protocol::{alice, alice::TransferProof, bob},
-    seed::Seed,
 };
 use anyhow::{Error, Result};
-use libp2p::{core::Multiaddr, identity::Keypair, NetworkBehaviour, PeerId};
+use libp2p::{core::Multiaddr, NetworkBehaviour, PeerId};
 use std::sync::Arc;
 use tracing::debug;
 use uuid::Uuid;
@@ -49,17 +48,15 @@ pub struct Swap {
 
 pub struct Builder {
     swap_id: Uuid,
-    identity: Keypair,
     db: Database,
 
-    alice_address: Multiaddr,
-    alice_peer_id: PeerId,
-
     bitcoin_wallet: Arc<bitcoin::Wallet>,
     monero_wallet: Arc<monero::Wallet>,
 
     init_params: InitParams,
     execution_params: ExecutionParams,
+
+    event_loop_handle: bob::EventLoopHandle,
 }
 
 enum InitParams {
@@ -70,27 +67,21 @@ enum InitParams {
 impl Builder {
     #[allow(clippy::too_many_arguments)]
     pub fn new(
-        seed: Seed,
         db: Database,
         swap_id: Uuid,
         bitcoin_wallet: Arc<bitcoin::Wallet>,
         monero_wallet: Arc<monero::Wallet>,
-        alice_address: Multiaddr,
-        alice_peer_id: PeerId,
         execution_params: ExecutionParams,
+        event_loop_handle: bob::EventLoopHandle,
     ) -> Self {
-        let identity = seed.derive_libp2p_identity();
-
         Self {
             swap_id,
-            identity,
             db,
-            alice_address,
-            alice_peer_id,
             bitcoin_wallet,
             monero_wallet,
             init_params: InitParams::None,
             execution_params,
+            event_loop_handle,
         }
     }
 
@@ -101,57 +92,21 @@ impl Builder {
         }
     }
 
-    pub async fn build(self) -> Result<(bob::Swap, bob::EventLoop)> {
-        match self.init_params {
-            InitParams::New { btc_amount } => {
-                let initial_state = BobState::Started { btc_amount };
-
-                let (event_loop, event_loop_handle) = self.init_event_loop()?;
-
-                Ok((
-                    Swap {
-                        state: initial_state,
-                        event_loop_handle,
-                        db: self.db,
-                        bitcoin_wallet: self.bitcoin_wallet.clone(),
-                        monero_wallet: self.monero_wallet.clone(),
-                        swap_id: self.swap_id,
-                        execution_params: self.execution_params,
-                    },
-                    event_loop,
-                ))
-            }
-
-            InitParams::None => {
-                let resume_state = self.db.get_state(self.swap_id)?.try_into_bob()?.into();
-
-                let (event_loop, event_loop_handle) = self.init_event_loop()?;
-
-                Ok((
-                    Swap {
-                        state: resume_state,
-                        event_loop_handle,
-                        db: self.db,
-                        bitcoin_wallet: self.bitcoin_wallet.clone(),
-                        monero_wallet: self.monero_wallet.clone(),
-                        swap_id: self.swap_id,
-                        execution_params: self.execution_params,
-                    },
-                    event_loop,
-                ))
-            }
-        }
-    }
-
-    fn init_event_loop(
-        &self,
-    ) -> Result<(bob::event_loop::EventLoop, bob::event_loop::EventLoopHandle)> {
-        bob::event_loop::EventLoop::new(
-            &self.identity,
-            self.alice_peer_id,
-            self.alice_address.clone(),
-            self.bitcoin_wallet.clone(),
-        )
+    pub fn build(self) -> Result<bob::Swap> {
+        let state = match self.init_params {
+            InitParams::New { btc_amount } => BobState::Started { btc_amount },
+            InitParams::None => self.db.get_state(self.swap_id)?.try_into_bob()?.into(),
+        };
+
+        Ok(Swap {
+            state,
+            event_loop_handle: self.event_loop_handle,
+            db: self.db,
+            bitcoin_wallet: self.bitcoin_wallet.clone(),
+            monero_wallet: self.monero_wallet.clone(),
+            swap_id: self.swap_id,
+            execution_params: self.execution_params,
+        })
     }
 }
 

swap/tests/testutils/mod.rs

@@ -54,16 +54,23 @@ struct BobParams {
 }
 
 impl BobParams {
-    pub fn builder(&self) -> bob::Builder {
+    pub fn builder(&self, event_loop_handle: bob::EventLoopHandle) -> bob::Builder {
         bob::Builder::new(
-            self.seed,
             Database::open(&self.db_path.clone().as_path()).unwrap(),
             self.swap_id,
             self.bitcoin_wallet.clone(),
             self.monero_wallet.clone(),
-            self.alice_address.clone(),
-            self.alice_peer_id,
             self.execution_params,
+            event_loop_handle,
+        )
+    }
+
+    pub fn new_eventloop(&self) -> Result<(bob::EventLoop, bob::EventLoopHandle)> {
+        bob::EventLoop::new(
+            &self.seed.derive_libp2p_identity(),
+            self.alice_peer_id,
+            self.alice_address.clone(),
+            self.bitcoin_wallet.clone(),
         )
     }
 }
@@ -95,12 +102,13 @@ pub struct TestContext {
 
 impl TestContext {
     pub async fn new_swap_as_bob(&mut self) -> (bob::Swap, BobEventLoopJoinHandle) {
-        let (swap, event_loop) = self
+        let (event_loop, event_loop_handle) = self.bob_params.new_eventloop().unwrap();
+
+        let swap = self
             .bob_params
-            .builder()
+            .builder(event_loop_handle)
             .with_init_params(self.btc_amount)
             .build()
-            .await
             .unwrap();
 
         let join_handle = tokio::spawn(event_loop.run());
@@ -114,7 +122,9 @@ impl TestContext {
     ) -> (bob::Swap, BobEventLoopJoinHandle) {
         join_handle.abort();
 
-        let (swap, event_loop) = self.bob_params.builder().build().await.unwrap();
+        let (event_loop, event_loop_handle) = self.bob_params.new_eventloop().unwrap();
+
+        let swap = self.bob_params.builder(event_loop_handle).build().unwrap();
 
         let join_handle = tokio::spawn(event_loop.run());