Consensus message buffering and more (#114)

* CLI options and keystore integration

* Replace multiqueue with future::mpsc

* BFT gossip

* Revert to app_dirs

* generate_from_seed commented

* Refactor event loop

* Start consensus by timer

* Message buffering

* Minor fixes

* Work around duty-roster issue.

* some more minor fixes

* fix compilation

* more consistent formatting

* make bft input stream never conclude

* Minor fixes

* add timestamp module to executive

* more cleanups and logging

* Fixed message propagation

substrate/substrate/client/src/client.rs

@@ -45,6 +45,12 @@ pub trait BlockchainEvents {
 	fn import_notification_stream(&self) -> BlockchainEventStream;
 }
 
+/// Chain head information.
+pub trait ChainHead {
+	/// Get best block header.
+	fn best_block_header(&self) -> Result<block::Header, error::Error>;
+}
+
 /// Client info
 // TODO: split queue info from chain info and amalgamate into single struct.
 #[derive(Debug)]
@@ -377,6 +383,12 @@ impl<B, E> Client<B, E> where
 	pub fn justification(&self, id: &BlockId) -> error::Result<Option<primitives::bft::Justification>> {
 		self.backend.blockchain().justification(*id)
 	}
+
+	/// Get best block header.
+	pub fn best_block_header(&self) -> error::Result<block::Header> {
+		let info = self.backend.blockchain().info().map_err(|e| error::Error::from_blockchain(Box::new(e)))?;
+		Ok(self.header(&BlockId::Hash(info.best_hash))?.expect("Best block header must always exist"))
+	}
 }
 
 impl<B, E> bft::BlockImport for Client<B, E>
@@ -420,6 +432,17 @@ impl<B, E> BlockchainEvents for Client<B, E>
 	}
 }
 
+impl<B, E> ChainHead for Client<B, E>
+	where
+		B: backend::Backend,
+		E: state_machine::CodeExecutor,
+		error::Error: From<<B::State as state_machine::backend::Backend>::Error>
+{
+	fn best_block_header(&self) -> error::Result<block::Header> {
+		Client::best_block_header(self)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;

substrate/substrate/client/src/lib.rs

@@ -44,6 +44,6 @@ pub mod genesis;
 pub mod block_builder;
 mod client;
 
-pub use client::{Client, ClientInfo, CallResult, ImportResult,
+pub use client::{Client, ClientInfo, CallResult, ImportResult, ChainHead,
 	BlockStatus, BlockOrigin, new_in_mem, BlockchainEventStream, BlockchainEvents};
 pub use blockchain::Info as ChainInfo;