transition rules

ethcore/src/engines/tendermint/message.rs

@@ -20,7 +20,7 @@ use util::*;
 use super::{Height, Round, BlockHash, Step};
 use rlp::{View, DecoderError, Decodable, Decoder, Encodable, RlpStream, Stream};
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Clone)]
 pub struct ConsensusMessage {
 	pub signature: H520,
 	pub height: Height,
@@ -30,12 +30,16 @@ pub struct ConsensusMessage {
 }
 
 impl ConsensusMessage {
+	pub fn is_height(&self, height: Height) -> bool {
+		self.height == height
+	}
+
 	pub fn is_round(&self, height: Height, round: Round) -> bool {
 		self.height == height && self.round == round
 	}
 
-	pub fn is_step(&self, height: Height, round: Round, step: &Step) -> bool {
+	pub fn is_step(&self, height: Height, round: Round, step: Step) -> bool {
-		self.height == height && self.round == round && &self.step == step
+		self.height == height && self.round == round && self.step == step
 	}
 
 	pub fn is_aligned(&self, height: Height, round: Round, block_hash: Option<H256>) -> bool {
@@ -79,7 +83,7 @@ impl Decodable for Step {
 		match try!(decoder.as_rlp().as_val()) {
 			0u8 => Ok(Step::Prevote),
 			1 => Ok(Step::Precommit),
-			_ => Err(DecoderError::Custom("Unknown step.")),
+			_ => Err(DecoderError::Custom("Invalid step.")),
 		}
 	}
 }

ethcore/src/engines/tendermint/mod.rs

@@ -41,11 +41,11 @@ use evm::Schedule;
 use io::{IoService, IoChannel};
 use service::ClientIoMessage;
 use self::message::ConsensusMessage;
-use self::timeout::{TransitionHandler, NextStep};
+use self::timeout::TransitionHandler;
 use self::params::TendermintParams;
 use self::vote_collector::VoteCollector;
 
-#[derive(Debug, PartialEq, Eq, Clone)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum Step {
 	Propose,
 	Prevote,
@@ -65,7 +65,7 @@ pub struct Tendermint {
 	params: CommonParams,
 	our_params: TendermintParams,
 	builtins: BTreeMap<Address, Builtin>,
-	step_service: IoService<NextStep>,
+	step_service: IoService<Step>,
 	/// Address to be used as authority.
 	authority: RwLock<Address>,
 	/// Blockchain height.
@@ -92,7 +92,7 @@ impl Tendermint {
 				params: params,
 				our_params: our_params,
 				builtins: builtins,
-				step_service: try!(IoService::<NextStep>::start()),
+				step_service: try!(IoService::<Step>::start()),
 				authority: RwLock::new(Address::default()),
 				height: AtomicUsize::new(0),
 				round: AtomicUsize::new(0),
@@ -125,6 +125,14 @@ impl Tendermint {
 		}
 	}
 
+	fn to_step(&self, step: Step) {
+		*self.step.write() = step;
+		match step {
+			Step::Propose => self.update_sealing(),
+			_ => {},
+		}
+	}
+
 	fn nonce_proposer(&self, proposer_nonce: usize) -> &Address {
 		let ref p = self.our_params;
 		p.authorities.get(proposer_nonce % p.authority_n).unwrap()
@@ -148,11 +156,19 @@ impl Tendermint {
 	}
 
 	fn is_current(&self, message: &ConsensusMessage) -> bool {
-		message.is_step(self.height.load(AtomicOrdering::SeqCst), self.round.load(AtomicOrdering::SeqCst), &self.step.read()) 
+		message.is_height(self.height.load(AtomicOrdering::SeqCst)) 
 	}
 
 	fn has_enough_any_votes(&self) -> bool {
-		self.votes.count_step_votes(self.height.load(AtomicOrdering::SeqCst), self.round.load(AtomicOrdering::SeqCst), &self.step.read()) > self.threshold()	
+		self.votes.count_step_votes(self.height.load(AtomicOrdering::SeqCst), self.round.load(AtomicOrdering::SeqCst), *self.step.read()) > self.threshold()	
+	}
+
+	fn has_enough_step_votes(&self, message: &ConsensusMessage) -> bool {
+		self.votes.count_step_votes(message.height, message.round, message.step) > self.threshold()	
+	}
+
+	fn has_enough_aligned_votes(&self, message: &ConsensusMessage) -> bool {
+		self.votes.aligned_signatures(&message).len() > self.threshold()
 	}
 }
 
@@ -272,19 +288,38 @@ impl Engine for Tendermint {
 			try!(Err(BlockError::InvalidSeal));
 		}
 
-		// Check if the message affects the current step.
+		self.votes.vote(message.clone(), sender);
+
+		// Check if the message should be handled right now.
 		if self.is_current(&message) {
-				match *self.step.read() {
+			let next_step = match *self.step.read() {
-					Step::Prevote => {
+				Step::Precommit if self.has_enough_aligned_votes(&message) => {
-						let votes = self.votes.aligned_signatures(&message);
+					if message.block_hash.is_none() {
-						if votes.len() > self.threshold() {
+						self.round.fetch_add(1, AtomicOrdering::SeqCst);
+						Some(Step::Propose)
+					} else {
+						Some(Step::Commit)
 					}
 				},
-					Step::Precommit => {},
+				Step::Precommit if self.has_enough_step_votes(&message) => {
-					_ => {},
+					self.round.store(message.round, AtomicOrdering::SeqCst);
+					Some(Step::Precommit)
+				},
+				Step::Prevote if self.has_enough_aligned_votes(&message) => Some(Step::Precommit),
+				Step::Prevote if self.has_enough_step_votes(&message) => {
+					self.round.store(message.round, AtomicOrdering::SeqCst);
+					Some(Step::Prevote)
+				},
+				_ => None,
+			};
+
+			if let Some(step) = next_step {
+				if let Err(io_err) = self.step_service.send_message(step) {
+					warn!(target: "poa", "Could not proceed to next step {}.", io_err)
 				}
 			}
-		self.votes.vote(message, sender);
+		}
+		
 		Err(BlockError::InvalidSeal.into())
 	}
 

ethcore/src/engines/tendermint/timeout.rs

@@ -57,25 +57,22 @@ impl Default for TendermintTimeouts {
 	}
 }
 
-#[derive(Clone)]
-pub struct NextStep(Step);
-
 /// Timer token representing the consensus step timeouts.
 pub const ENGINE_TIMEOUT_TOKEN: TimerToken = 23;
 
-fn set_timeout(io: &IoContext<NextStep>, timeout: Duration) {
+fn set_timeout(io: &IoContext<Step>, timeout: Duration) {
 	io.register_timer_once(ENGINE_TIMEOUT_TOKEN, timeout.num_milliseconds() as u64)
 		.unwrap_or_else(|e| warn!(target: "poa", "Failed to set consensus step timeout: {}.", e))
 }
 
-impl IoHandler<NextStep> for TransitionHandler {
+impl IoHandler<Step> for TransitionHandler {
-	fn initialize(&self, io: &IoContext<NextStep>) {
+	fn initialize(&self, io: &IoContext<Step>) {
 		if let Some(engine) = self.engine.upgrade() {
 			set_timeout(io, engine.our_params.timeouts.propose)
 		}
 	}
 
-	fn timeout(&self, io: &IoContext<NextStep>, timer: TimerToken) {
+	fn timeout(&self, io: &IoContext<Step>, timer: TimerToken) {
 		if timer == ENGINE_TIMEOUT_TOKEN {
 			if let Some(engine) = self.engine.upgrade() {
 				let next_step = match *engine.step.read() {
@@ -102,32 +99,24 @@ impl IoHandler<NextStep> for TransitionHandler {
 				};
 
 				if let Some(step) = next_step {
-					*engine.step.write() = step.clone();
+					engine.to_step(step)
-					if step == Step::Propose {
-						engine.update_sealing();
-					}
 				}
 			}
 		}
 	}
 
-	fn message(&self, io: &IoContext<NextStep>, message: &NextStep) {
+	fn message(&self, io: &IoContext<Step>, next_step: &Step) {
 		if let Some(engine) = self.engine.upgrade() {
-			match io.clear_timer(ENGINE_TIMEOUT_TOKEN) {
+			if let Err(io_err) = io.clear_timer(ENGINE_TIMEOUT_TOKEN) {
-				Ok(_) => {},
+				warn!(target: "poa", "Could not remove consensus timer {}.", io_err)
-				Err(io_err) => warn!(target: "poa", "Could not remove consensus timer {}.", io_err),
+			}
-			};
+			match *next_step {
-			let NextStep(next_step) = message.clone();
+				Step::Propose => set_timeout(io, engine.our_params.timeouts.propose),
-			*engine.step.write() = next_step.clone();
-			match next_step {
-				Step::Propose => {
-					engine.update_sealing();
-					set_timeout(io, engine.our_params.timeouts.propose)
-				},
 				Step::Prevote => set_timeout(io, engine.our_params.timeouts.prevote),
 				Step::Precommit => set_timeout(io, engine.our_params.timeouts.precommit),
 				Step::Commit => set_timeout(io, engine.our_params.timeouts.commit),
 			};
+			engine.to_step(*next_step);
 		}
 	}
 }

ethcore/src/engines/tendermint/vote_collector.rs

@@ -50,7 +50,7 @@ impl VoteCollector {
 		self.seal_signatures(message.height, message.round, message.block_hash)
 	}
 
-	pub fn count_step_votes(&self, height: Height, round: Round, step: &Step) -> usize {
+	pub fn count_step_votes(&self, height: Height, round: Round, step: Step) -> usize {
 		self.votes
 			.read()
 			.keys()