Make Message and VerifiedMessage generic over Verifier

CHANGELOG.md

@@ -19,14 +19,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `EchoBroadcast` and `DirectMessage` now use `ProtocolMessagePart` trait for their methods. ([#47])
 - Added normal broadcasts support in addition to echo ones; signatures of `Round` methods changed accordingly; added `Round::make_normal_broadcast()`. ([#47])
 - Serialization format is a part of `SessionParameters` now; `Round` and `Protocol` methods receive dynamic serializers/deserializers. ([#33])
-- Renamed `(Verified)MessageBundle` to `(Verified)Message`. ([#56])
+- Renamed `(Verified)MessageBundle` to `(Verified)Message`. Both are now generic over `Verifier`. ([#56])
 
 
 ### Added
 
 - `SerializableMap` wrapper for `BTreeMap` supporting more formats and providing some safety features. (#[32])
 - `DirectMessage::assert_is_none()` and `verify_is_some()`, same for `EchoBroadcast`. Users can now check that a part of the round message (echo or direct) is `None` as expected, and make a verifiable evidence if it is not. ([#46])
 - Re-export `digest` from the `session` module. ([#56])
+- Added `Message::destination()`. ([#56])
 
 
 [#32]: https://github.com/entropyxyz/manul/pull/32

examples/tests/async_runner.rs

@@ -23,12 +23,12 @@ use tracing_subscriber::{util::SubscriberInitExt, EnvFilter};
 struct MessageOut<SP: SessionParameters> {
     from: SP::Verifier,
     to: SP::Verifier,
-    message: Message,
+    message: Message<SP::Verifier>,
 }
 
 struct MessageIn<SP: SessionParameters> {
     from: SP::Verifier,
-    message: Message,
+    message: Message<SP::Verifier>,
 }
 
 /// Runs a session. Simulates what each participating party would run as the protocol progresses.

manul/src/session.rs

@@ -17,7 +17,7 @@ mod wire_format;
 
 pub use crate::protocol::{LocalError, RemoteError};
 pub use evidence::{Evidence, EvidenceError};
-pub use message::{VerifiedMessage, Message};
+pub use message::{Message, VerifiedMessage};
 pub use session::{CanFinalize, RoundAccumulator, RoundOutcome, Session, SessionId, SessionParameters};
 pub use transcript::{SessionOutcome, SessionReport};
 pub use wire_format::WireFormat;

manul/src/session/message.rs

@@ -177,19 +177,24 @@ impl<M> VerifiedMessagePart<M> {
 
 /// A signed message destined for another node.
 #[derive(Clone, Debug)]
-pub struct Message {
+pub struct Message<Verifier> {
+    destination: Verifier,
     direct_message: SignedMessagePart<DirectMessage>,
     echo_broadcast: SignedMessagePart<EchoBroadcast>,
     normal_broadcast: SignedMessagePart<NormalBroadcast>,
 }
 
-impl Message {
+impl<Verifier> Message<Verifier>
+where
+    Verifier: Clone,
+{
     #[allow(clippy::too_many_arguments)]
     pub(crate) fn new<SP>(
         rng: &mut impl CryptoRngCore,
         signer: &SP::Signer,
         session_id: &SessionId,
         round_id: RoundId,
+        destination: &Verifier,
         direct_message: DirectMessage,
         echo_broadcast: SignedMessagePart<EchoBroadcast>,
         normal_broadcast: SignedMessagePart<NormalBroadcast>,
@@ -199,12 +204,18 @@ impl Message {
     {
         let direct_message = SignedMessagePart::new::<SP>(rng, signer, session_id, round_id, direct_message)?;
         Ok(Self {
+            destination: destination.clone(),
             direct_message,
             echo_broadcast,
             normal_broadcast,
         })
     }
 
+    /// The verifier of the party this message is intended for.
+    pub fn destination(&self) -> &Verifier {
+        &self.destination
+    }
+
     pub(crate) fn unify_metadata(self) -> Option<CheckedMessage> {
         if self.echo_broadcast.metadata() != self.direct_message.metadata() {
             return None;
@@ -241,7 +252,7 @@ impl CheckedMessage {
         &self.metadata
     }
 
-    pub fn verify<SP>(self, verifier: &SP::Verifier) -> Result<VerifiedMessage<SP>, MessageVerificationError>
+    pub fn verify<SP>(self, verifier: &SP::Verifier) -> Result<VerifiedMessage<SP::Verifier>, MessageVerificationError>
     where
         SP: SessionParameters,
     {
@@ -264,25 +275,21 @@ impl CheckedMessage {
 // signatures of message parts (direct, broadcast etc) from the original [`Message`] successfully verified.
 
 /// A [`Message`] that had its metadata and signatures verified.
-#[derive_where::derive_where(Debug)]
-#[derive(Clone)]
-pub struct VerifiedMessage<SP: SessionParameters> {
-    from: SP::Verifier,
+#[derive(Debug, Clone)]
+pub struct VerifiedMessage<Verifier> {
+    from: Verifier,
     metadata: MessageMetadata,
     direct_message: VerifiedMessagePart<DirectMessage>,
     echo_broadcast: VerifiedMessagePart<EchoBroadcast>,
     normal_broadcast: VerifiedMessagePart<NormalBroadcast>,
 }
 
-impl<SP> VerifiedMessage<SP>
-where
-    SP: SessionParameters,
-{
+impl<Verifier> VerifiedMessage<Verifier> {
     pub(crate) fn metadata(&self) -> &MessageMetadata {
         &self.metadata
     }
 
-    pub(crate) fn from(&self) -> &SP::Verifier {
+    pub(crate) fn from(&self) -> &Verifier {
         &self.from
     }
 

manul/src/session/session.rs

@@ -130,7 +130,7 @@ pub enum RoundOutcome<P: Protocol, SP: SessionParameters> {
         /// The session object for the new round.
         session: Session<P, SP>,
         /// The messages intended for the new round cached during the previous round.
-        cached_messages: Vec<VerifiedMessage<SP>>,
+        cached_messages: Vec<VerifiedMessage<SP::Verifier>>,
     },
 }
 
@@ -231,7 +231,7 @@ where
         &self,
         rng: &mut impl CryptoRngCore,
         destination: &SP::Verifier,
-    ) -> Result<(Message, ProcessedArtifact<SP>), LocalError> {
+    ) -> Result<(Message<SP::Verifier>, ProcessedArtifact<SP>), LocalError> {
         let (direct_message, artifact) =
             self.round
                 .make_direct_message_with_artifact(rng, &self.serializer, destination)?;
@@ -241,6 +241,7 @@ where
             &self.signer,
             &self.session_id,
             self.round.id(),
+            destination,
             direct_message,
             self.echo_broadcast.clone(),
             self.normal_broadcast.clone(),
@@ -285,8 +286,8 @@ where
         &self,
         accum: &mut RoundAccumulator<P, SP>,
         from: &SP::Verifier,
-        message: Message,
-    ) -> Result<Option<VerifiedMessage<SP>>, LocalError> {
+        message: Message<SP::Verifier>,
+    ) -> Result<Option<VerifiedMessage<SP::Verifier>>, LocalError> {
         // Quick preliminary checks, before we proceed with more expensive verification
         let key = self.verifier();
         if self.transcript.is_banned(from) || accum.is_banned(from) {
@@ -381,7 +382,7 @@ where
     pub fn process_message(
         &self,
         rng: &mut impl CryptoRngCore,
-        message: VerifiedMessage<SP>,
+        message: VerifiedMessage<SP::Verifier>,
     ) -> ProcessedMessage<P, SP> {
         let processed = self.round.receive_message(
             rng,
@@ -544,7 +545,7 @@ pub struct RoundAccumulator<P: Protocol, SP: SessionParameters> {
     processing: BTreeSet<SP::Verifier>,
     payloads: BTreeMap<SP::Verifier, Payload>,
     artifacts: BTreeMap<SP::Verifier, Artifact>,
-    cached: BTreeMap<SP::Verifier, BTreeMap<RoundId, VerifiedMessage<SP>>>,
+    cached: BTreeMap<SP::Verifier, BTreeMap<RoundId, VerifiedMessage<SP::Verifier>>>,
     echo_broadcasts: BTreeMap<SP::Verifier, SignedMessagePart<EchoBroadcast>>,
     normal_broadcasts: BTreeMap<SP::Verifier, SignedMessagePart<NormalBroadcast>>,
     direct_messages: BTreeMap<SP::Verifier, SignedMessagePart<DirectMessage>>,
@@ -625,7 +626,7 @@ where
         }
     }
 
-    fn mark_processing(&mut self, message: &VerifiedMessage<SP>) -> Result<(), LocalError> {
+    fn mark_processing(&mut self, message: &VerifiedMessage<SP::Verifier>) -> Result<(), LocalError> {
         if !self.processing.insert(message.from().clone()) {
             Err(LocalError::new(format!(
                 "A message from {:?} is already marked as being processed",
@@ -732,7 +733,7 @@ where
         }
     }
 
-    fn cache_message(&mut self, message: VerifiedMessage<SP>) -> Result<(), LocalError> {
+    fn cache_message(&mut self, message: VerifiedMessage<SP::Verifier>) -> Result<(), LocalError> {
         let from = message.from().clone();
         let round_id = message.metadata().round_id();
         let cached = self.cached.entry(from.clone()).or_default();
@@ -754,14 +755,14 @@ pub struct ProcessedArtifact<SP: SessionParameters> {
 
 #[derive(Debug)]
 pub struct ProcessedMessage<P: Protocol, SP: SessionParameters> {
-    message: VerifiedMessage<SP>,
+    message: VerifiedMessage<SP::Verifier>,
     processed: Result<Payload, ReceiveError<SP::Verifier, P>>,
 }
 
-fn filter_messages<SP: SessionParameters>(
-    messages: BTreeMap<SP::Verifier, BTreeMap<RoundId, VerifiedMessage<SP>>>,
+fn filter_messages<Verifier>(
+    messages: BTreeMap<Verifier, BTreeMap<RoundId, VerifiedMessage<Verifier>>>,
     round_id: RoundId,
-) -> Vec<VerifiedMessage<SP>> {
+) -> Vec<VerifiedMessage<Verifier>> {
     messages
         .into_values()
         .filter_map(|mut messages| messages.remove(&round_id))
@@ -781,7 +782,7 @@ mod tests {
             Deserializer, DirectMessage, EchoBroadcast, NormalBroadcast, Protocol, ProtocolError,
             ProtocolValidationError, RoundId,
         },
-        testing::{BinaryFormat, TestSessionParams},
+        testing::{BinaryFormat, TestSessionParams, TestVerifier},
     };
 
     #[test]
@@ -835,9 +836,9 @@ mod tests {
         assert!(impls!(Session<DummyProtocol, SP>: Sync));
 
         // These objects are sent to/from message processing tasks
-        assert!(impls!(Message: Send));
+        assert!(impls!(Message<TestVerifier>: Send));
         assert!(impls!(ProcessedArtifact<SP>: Send));
-        assert!(impls!(VerifiedMessage<SP>: Send));
+        assert!(impls!(VerifiedMessage<TestVerifier>: Send));
         assert!(impls!(ProcessedMessage<DummyProtocol, SP>: Send));
     }
 }

manul/src/testing/run_sync.rs

@@ -24,7 +24,7 @@ enum State<P: Protocol, SP: SessionParameters> {
 struct RoundMessage<SP: SessionParameters> {
     from: SP::Verifier,
     to: SP::Verifier,
-    message: Message,
+    message: Message<SP::Verifier>,
 }
 
 #[allow(clippy::type_complexity)]