From a48823a665d6843340f4238a093ae5783d7c9997 Mon Sep 17 00:00:00 2001
From: Franck Royer <franck@coblox.tech>
Date: Fri, 5 Feb 2021 16:40:11 +1100
Subject: [PATCH] Re-organise Alice state to be more coherent with the msg
 sequence

---
 swap/src/protocol/alice/execution_setup.rs | 53 ++++++++--------------
 swap/src/protocol/alice/state.rs           | 32 +++++++------
 2 files changed, 38 insertions(+), 47 deletions(-)

diff --git a/swap/src/protocol/alice/execution_setup.rs b/swap/src/protocol/alice/execution_setup.rs
index aa7ca641..967ba26f 100644
--- a/swap/src/protocol/alice/execution_setup.rs
+++ b/swap/src/protocol/alice/execution_setup.rs
@@ -63,47 +63,34 @@ impl Behaviour {
     pub fn run(&mut self, bob: PeerId, state0: State0) {
         self.inner
             .do_protocol_listener(bob, move |mut substream| async move {
-                let message1 = state0.next_message();
-
-                let state1 = {
-                    let message0 = serde_cbor::from_slice::<Message0>(
-                        &substream.read_message(BUF_SIZE).await?,
-                    )
-                    .context("failed to deserialize message0")?;
-                    state0.receive(message0)?
-                };
+                let message0 =
+                    serde_cbor::from_slice::<Message0>(&substream.read_message(BUF_SIZE).await?)
+                        .context("failed to deserialize message0")?;
+                let state1 = state0.receive(message0)?;
 
                 substream
                     .write_message(
-                        &serde_cbor::to_vec(&message1).context("failed to serialize message1")?,
+                        &serde_cbor::to_vec(&state1.next_message())
+                            .context("failed to serialize message1")?,
                     )
                     .await?;
 
-                let state2 = {
-                    let message2 = serde_cbor::from_slice::<Message2>(
-                        &substream.read_message(BUF_SIZE).await?,
-                    )
-                    .context("failed to deserialize message2")?;
-                    state1.receive(message2)
-                };
-
-                {
-                    let message3 = state2.next_message();
-                    substream
-                        .write_message(
-                            &serde_cbor::to_vec(&message3)
-                                .context("failed to serialize message3")?,
-                        )
-                        .await?;
-                }
+                let message2 =
+                    serde_cbor::from_slice::<Message2>(&substream.read_message(BUF_SIZE).await?)
+                        .context("failed to deserialize message2")?;
+                let state2 = state1.receive(message2);
 
-                let state3 = {
-                    let message4 = serde_cbor::from_slice::<Message4>(
-                        &substream.read_message(BUF_SIZE).await?,
+                substream
+                    .write_message(
+                        &serde_cbor::to_vec(&state2.next_message())
+                            .context("failed to serialize message3")?,
                     )
-                    .context("failed to deserialize message4")?;
-                    state2.receive(message4)?
-                };
+                    .await?;
+
+                let message4 =
+                    serde_cbor::from_slice::<Message4>(&substream.read_message(BUF_SIZE).await?)
+                        .context("failed to deserialize message4")?;
+                let state3 = state2.receive(message4)?;
 
                 Ok(state3)
             })
diff --git a/swap/src/protocol/alice/state.rs b/swap/src/protocol/alice/state.rs
index 55ebc741..a6bbf21f 100644
--- a/swap/src/protocol/alice/state.rs
+++ b/swap/src/protocol/alice/state.rs
@@ -133,20 +133,6 @@ impl State0 {
         }
     }
 
-    pub fn next_message(&self) -> Message1 {
-        Message1 {
-            A: self.a.public(),
-            S_a_monero: monero::PublicKey::from_private_key(&monero::PrivateKey {
-                scalar: self.s_a.into_ed25519(),
-            }),
-            S_a_bitcoin: self.s_a.into_secp256k1().into(),
-            dleq_proof_s_a: self.dleq_proof_s_a.clone(),
-            v_a: self.v_a,
-            redeem_address: self.redeem_address.clone(),
-            punish_address: self.punish_address.clone(),
-        }
-    }
-
     pub fn receive(self, msg: Message0) -> Result<State1> {
         msg.dleq_proof_s_b.verify(
             msg.S_b_bitcoin.clone().into(),
@@ -165,6 +151,8 @@ impl State0 {
             S_b_monero: msg.S_b_monero,
             S_b_bitcoin: msg.S_b_bitcoin,
             v,
+            v_a: self.v_a,
+            dleq_proof_s_a: self.dleq_proof_s_a,
             btc: self.btc,
             xmr: self.xmr,
             cancel_timelock: self.cancel_timelock,
@@ -184,6 +172,8 @@ pub struct State1 {
     S_b_monero: monero::PublicKey,
     S_b_bitcoin: bitcoin::PublicKey,
     v: monero::PrivateViewKey,
+    v_a: monero::PrivateViewKey,
+    dleq_proof_s_a: cross_curve_dleq::Proof,
     #[serde(with = "::bitcoin::util::amount::serde::as_sat")]
     btc: bitcoin::Amount,
     xmr: monero::Amount,
@@ -195,6 +185,20 @@ pub struct State1 {
 }
 
 impl State1 {
+    pub fn next_message(&self) -> Message1 {
+        Message1 {
+            A: self.a.public(),
+            S_a_monero: monero::PublicKey::from_private_key(&monero::PrivateKey {
+                scalar: self.s_a.into_ed25519(),
+            }),
+            S_a_bitcoin: self.s_a.into_secp256k1().into(),
+            dleq_proof_s_a: self.dleq_proof_s_a.clone(),
+            v_a: self.v_a,
+            redeem_address: self.redeem_address.clone(),
+            punish_address: self.punish_address.clone(),
+        }
+    }
+
     pub fn receive(self, msg: Message2) -> State2 {
         State2 {
             a: self.a,