From 4f1afccf975292828ce2b3f78204ab7cd92313ca Mon Sep 17 00:00:00 2001
From: Robert Habermeier <rphmeier@gmail.com>
Date: Mon, 13 Feb 2017 16:49:01 +0100
Subject: [PATCH] best_block_header function

---
 ethcore/light/src/client/mod.rs | 15 +++++++++++++--
 rpc/src/v1/helpers/dispatch.rs  |  7 ++-----
 rpc/src/v1/impls/light/eth.rs   |  3 +--
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/ethcore/light/src/client/mod.rs b/ethcore/light/src/client/mod.rs
index bb43a9f5b..a113b4367 100644
--- a/ethcore/light/src/client/mod.rs
+++ b/ethcore/light/src/client/mod.rs
@@ -31,8 +31,7 @@ use ethcore::service::ClientIoMessage;
 use ethcore::encoded;
 use io::IoChannel;
 
-use util::hash::H256;
-use util::{Bytes, Mutex, RwLock};
+use util::{Bytes, H256, Mutex, RwLock};
 
 use self::header_chain::HeaderChain;
 
@@ -60,6 +59,9 @@ pub trait LightChainClient: Send + Sync {
 	/// Attempt to get block header by block id.
 	fn block_header(&self, id: BlockId) -> Option<encoded::Header>;
 
+	/// Get the best block header.
+	fn best_block_header(&self) -> encoded::Header;
+
 	/// Query whether a block is known.
 	fn is_known(&self, hash: &H256) -> bool;
 
@@ -157,6 +159,11 @@ impl Client {
 		self.chain.block_header(id)
 	}
 
+	/// Get the best block header.
+	pub fn best_block_header(&self) -> encoded::Header {
+		self.chain.best_header()
+	}
+
 	/// Flush the header queue.
 	pub fn flush_queue(&self) {
 		self.queue.flush()
@@ -223,6 +230,10 @@ impl LightChainClient for Client {
 		Client::block_header(self, id)
 	}
 
+	fn best_block_header(&self) -> encoded::Header {
+		Client::best_block_header(self)
+	}
+
 	fn is_known(&self, hash: &H256) -> bool {
 		self.status(hash) == BlockStatus::InChain
 	}
diff --git a/rpc/src/v1/helpers/dispatch.rs b/rpc/src/v1/helpers/dispatch.rs
index 6174c060b..de0207d79 100644
--- a/rpc/src/v1/helpers/dispatch.rs
+++ b/rpc/src/v1/helpers/dispatch.rs
@@ -30,7 +30,6 @@ use util::sha3::Hashable;
 
 use ethkey::Signature;
 use ethsync::LightSync;
-use ethcore::ids::BlockId;
 use ethcore::miner::MinerService;
 use ethcore::client::MiningBlockChainClient;
 use ethcore::transaction::{Action, SignedTransaction, PendingTransaction, Transaction};
@@ -190,8 +189,7 @@ impl Dispatcher for LightDispatcher {
 		-> BoxFuture<FilledTransactionRequest, Error>
 	{
 		let request = request;
-		let gas_limit = self.client.block_header(BlockId::Latest)
-			.expect("Best block header always kept; qed").gas_limit();
+		let gas_limit = self.client.best_block_header().gas_limit();
 
 		future::ok(FilledTransactionRequest {
 			from: request.from.unwrap_or(default_sender),
@@ -211,8 +209,7 @@ impl Dispatcher for LightDispatcher {
 	{
 		let network_id = None; // TODO: fetch from client.
 		let address = filled.from;
-		let best_header = self.client.block_header(BlockId::Latest)
-			.expect("Best block header always kept; qed");
+		let best_header = self.client.best_block_header();
 
 		let with_nonce = move |filled: FilledTransactionRequest, nonce| {
 			let t = Transaction {
diff --git a/rpc/src/v1/impls/light/eth.rs b/rpc/src/v1/impls/light/eth.rs
index f72a9bb69..18bd9682e 100644
--- a/rpc/src/v1/impls/light/eth.rs
+++ b/rpc/src/v1/impls/light/eth.rs
@@ -305,8 +305,7 @@ impl Eth for EthClient {
 	}
 
 	fn send_raw_transaction(&self, raw: Bytes) -> Result<RpcH256, Error> {
-		let best_header = self.client.block_header(BlockId::Latest)
-			.expect("best block header always stored; qed").decode();
+		let best_header = self.client.best_block_header().decode();
 
 		UntrustedRlp::new(&raw.into_vec()).as_val()
 			.map_err(errors::from_rlp_error)