Save state for Alice at specific points in the swap

swap/src/alice.rs

@@ -31,7 +31,7 @@ use crate::{
         transport::SwapTransport,
         TokioExecutor,
     },
-    storage::Database,
+    storage::{self, Database},
     SwapAmounts, PUNISH_TIMELOCK, REFUND_TIMELOCK,
 };
 use xmr_btc::{
@@ -44,7 +44,7 @@ use xmr_btc::{
 pub async fn swap(
     bitcoin_wallet: Arc<bitcoin::Wallet>,
     monero_wallet: Arc<monero::Wallet>,
-    _db: Database<crate::storage::Alice>,
+    db: Database<storage::Alice>,
     listen: Multiaddr,
     transport: SwapTransport,
     behaviour: Alice,
@@ -175,6 +175,9 @@ pub async fn swap(
         other => panic!("Unexpected event: {:?}", other),
     };
 
+    db.insert_latest_state(&storage::Alice::Handshaken(state3.clone()))
+        .await?;
+
     info!("Handshake complete, we now have State3 for Alice.");
 
     let network = Arc::new(Mutex::new(Network {
@@ -185,7 +188,7 @@ pub async fn swap(
     let mut action_generator = action_generator(
         network.clone(),
         bitcoin_wallet.clone(),
-        state3,
+        state3.clone(),
         TX_LOCK_MINE_TIMEOUT,
     );
 
@@ -200,33 +203,60 @@ pub async fn swap(
                 public_spend_key,
                 public_view_key,
             }) => {
+                db.insert_latest_state(&storage::Alice::BtcLocked(state3.clone()))
+                    .await?;
+
                 let (transfer_proof, _) = monero_wallet
                     .transfer(public_spend_key, public_view_key, amount)
                     .await?;
 
+                db.insert_latest_state(&storage::Alice::XmrLocked(state3.clone()))
+                    .await?;
+
                 let mut guard = network.as_ref().lock().await;
                 guard.send_message2(transfer_proof).await;
                 info!("Sent transfer proof");
             }
 
             GeneratorState::Yielded(Action::RedeemBtc(tx)) => {
+                db.insert_latest_state(&storage::Alice::BtcRedeemable {
+                    state: state3.clone(),
+                    redeem_tx: tx.clone(),
+                })
+                .await?;
+
                 let _ = bitcoin_wallet.broadcast_signed_transaction(tx).await?;
             }
             GeneratorState::Yielded(Action::CancelBtc(tx)) => {
                 let _ = bitcoin_wallet.broadcast_signed_transaction(tx).await?;
             }
             GeneratorState::Yielded(Action::PunishBtc(tx)) => {
+                db.insert_latest_state(&storage::Alice::BtcPunishable(state3.clone()))
+                    .await?;
+
                 let _ = bitcoin_wallet.broadcast_signed_transaction(tx).await?;
             }
             GeneratorState::Yielded(Action::CreateMoneroWalletForOutput {
                 spend_key,
                 view_key,
             }) => {
+                db.insert_latest_state(&storage::Alice::BtcRefunded {
+                    state: state3.clone(),
+                    spend_key,
+                    view_key,
+                })
+                .await?;
+
                 monero_wallet
                     .create_and_load_wallet_for_output(spend_key, view_key)
                     .await?;
             }
-            GeneratorState::Complete(()) => return Ok(()),
+            GeneratorState::Complete(()) => {
+                db.insert_latest_state(&storage::Alice::SwapComplete)
+                    .await?;
+
+                return Ok(());
+            }
         }
     }
 }

swap/src/bob.rs

@@ -174,10 +174,6 @@ pub async fn swap(
                     .await?;
             }
             GeneratorState::Yielded(bob::Action::SendBtcRedeemEncsig(tx_redeem_encsig)) => {
-                // FIXME: We _know_ that this action is only yielded if the monero has been
-                // locked. This only works because we know that this is the case, but it may be
-                // cleaner to save the state inside an implementation of `watch_for_transfer` or
-                // modify the library code to make this easier
                 db.insert_latest_state(&storage::Bob::XmrLocked(state2.clone()))
                     .await?;
 
@@ -198,10 +194,6 @@ pub async fn swap(
                 spend_key,
                 view_key,
             }) => {
-                // FIXME: We _know_ that this action is only yielded if the bitcoin has been
-                // redeemed. This only works because we know that this is the case, but it may
-                // be cleaner to save the state inside an implementation of `watch_for_transfer`
-                // or modify the library code to make this easier
                 db.insert_latest_state(&storage::Bob::BtcRedeemed(state2.clone()))
                     .await?;
 
@@ -216,9 +208,6 @@ pub async fn swap(
                 let _ = bitcoin_wallet
                     .broadcast_signed_transaction(tx_cancel)
                     .await?;
-
-                db.insert_latest_state(&storage::Bob::BtcRefundable(state2.clone()))
-                    .await?;
             }
             GeneratorState::Yielded(bob::Action::RefundBtc(tx_refund)) => {
                 db.insert_latest_state(&storage::Bob::BtcRefundable(state2.clone()))

swap/src/storage.rs

@@ -1,7 +1,27 @@
 use anyhow::{anyhow, Context, Result};
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
 use std::path::Path;
-use xmr_btc::{alice, bitcoin::EncryptedSignature, bob, serde::monero_private_key};
+use xmr_btc::{alice, bob, monero, serde::monero_private_key};
+
+#[allow(clippy::large_enum_variant)]
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub enum Alice {
+    Handshaken(alice::State3),
+    BtcLocked(alice::State3),
+    XmrLocked(alice::State3),
+    BtcRedeemable {
+        state: alice::State3,
+        redeem_tx: bitcoin::Transaction,
+    },
+    BtcPunishable(alice::State3),
+    BtcRefunded {
+        state: alice::State3,
+        #[serde(with = "monero_private_key")]
+        spend_key: monero::PrivateKey,
+        view_key: monero::PrivateViewKey,
+    },
+    SwapComplete,
+}
 
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub enum Bob {
@@ -13,25 +33,6 @@ pub enum Bob {
     SwapComplete,
 }
 
-#[allow(clippy::large_enum_variant)]
-#[derive(Clone, Debug, Deserialize, Serialize)]
-pub enum Alice {
-    Handshaken(alice::State3),
-    BtcLocked(alice::State3),
-    XmrLocked(alice::State3),
-    ReceivedEncSig {
-        state: alice::State3,
-        enc_sig: EncryptedSignature,
-    },
-    BtcCancelled(alice::State3),
-    BtcRefunded {
-        state: alice::State3,
-        #[serde(with = "monero_private_key")]
-        s_b: monero::PrivateKey,
-    },
-    SwapComplete,
-}
-
 pub struct Database<T>
 where
     T: Serialize + DeserializeOwned,
@@ -57,6 +58,8 @@ where
         })
     }
 
+    // TODO: Add method to update state
+
     pub async fn insert_latest_state(&self, state: &T) -> Result<()> {
         let key = serialize(&Self::LAST_STATE_KEY)?;
         let new_value = serialize(&state).context("Could not serialize new state value")?;