add is_new_best method to engines

ethcore/src/engines/mod.rs

@@ -36,6 +36,8 @@ use account_provider::AccountProvider;
 use block::ExecutedBlock;
 use spec::CommonParams;
 use evm::Schedule;
+use ethereum::ethash;
+use blockchain::extras::BlockDetails;
 
 /// Voting errors.
 #[derive(Debug)]
@@ -157,7 +159,9 @@ pub trait Engine : Sync + Send {
 	fn execute_builtin(&self, a: &Address, input: &[u8], output: &mut BytesRef) { self.builtins().get(a).unwrap().execute(input, output); }
 
 	/// Check if new block should be chosen as the one  in chain.
-	fn is_new_best_block(&self, parent_details: BlockDetails, best_header: HeaderView, new_header: HeaderView) -> bool;
+	fn is_new_best_block(&self, best_total_difficulty: U256, _best_header: HeaderView, parent_details: &BlockDetails, new_header: &HeaderView) -> bool {
+		ethash::is_new_best_block(best_total_difficulty, parent_details, new_header)
+	}
 
 	// TODO: sealing stuff - though might want to leave this for later.
 }

ethcore/src/ethereum/ethash.rs

@@ -22,6 +22,7 @@ use engines::Engine;
 use evm::Schedule;
 use ethjson;
 use rlp::{self, UntrustedRlp, View};
+use blockchain::extras::BlockDetails;
 
 /// Ethash params.
 #[derive(Debug, PartialEq)]
@@ -273,6 +274,11 @@ impl Engine for Ethash {
 	fn verify_transaction(&self, t: &SignedTransaction, _header: &Header) -> Result<(), Error> {
 		t.sender().map(|_|()) // Perform EC recovery and cache sender
 	}
+
+	/// Check if new block should be chosen as the one  in chain.
+	fn is_new_best_block(&self, best_total_difficulty: U256, _best_header: HeaderView, parent_details: &BlockDetails, new_header: &HeaderView) -> bool {
+		is_new_best_block(best_total_difficulty, parent_details, new_header)
+	}
 }
 
 #[cfg_attr(feature="dev", allow(wrong_self_convention))] // to_ethash should take self
@@ -347,6 +353,12 @@ impl Ethash {
 	}
 }
 
+/// Check if a new block should replace the best blockchain block.
+pub fn is_new_best_block(best_total_difficulty: U256, parent_details: &BlockDetails, new_header: &HeaderView) -> bool {
+	parent_details.total_difficulty + new_header.difficulty() > best_total_difficulty
+}
+
+
 impl Header {
 	/// Get the none field of the header.
 	pub fn nonce(&self) -> H64 {

ethcore/src/tests/helpers.rs

@@ -277,7 +277,7 @@ fn new_db(path: &str) -> Arc<Database> {
 pub fn generate_dummy_blockchain(block_number: u32) -> GuardedTempResult<BlockChain> {
 	let temp = RandomTempPath::new();
 	let db = new_db(temp.as_str());
-	let bc = BlockChain::new(BlockChainConfig::default(), &create_unverifiable_block(0, H256::zero()), db.clone());
+	let bc = BlockChain::new(BlockChainConfig::default(), &create_unverifiable_block(0, H256::zero()), db.clone(), Spec::new_null().engine);
 
 	let mut batch = db.transaction();
 	for block_order in 1..block_number {
@@ -295,7 +295,7 @@ pub fn generate_dummy_blockchain(block_number: u32) -> GuardedTempResult<BlockCh
 pub fn generate_dummy_blockchain_with_extra(block_number: u32) -> GuardedTempResult<BlockChain> {
 	let temp = RandomTempPath::new();
 	let db = new_db(temp.as_str());
-	let bc = BlockChain::new(BlockChainConfig::default(), &create_unverifiable_block(0, H256::zero()), db.clone());
+	let bc = BlockChain::new(BlockChainConfig::default(), &create_unverifiable_block(0, H256::zero()), db.clone(), Spec::new_null().engine);
 
 
 	let mut batch = db.transaction();
@@ -314,7 +314,7 @@ pub fn generate_dummy_blockchain_with_extra(block_number: u32) -> GuardedTempRes
 pub fn generate_dummy_empty_blockchain() -> GuardedTempResult<BlockChain> {
 	let temp = RandomTempPath::new();
 	let db = new_db(temp.as_str());
-	let bc = BlockChain::new(BlockChainConfig::default(), &create_unverifiable_block(0, H256::zero()), db.clone());
+	let bc = BlockChain::new(BlockChainConfig::default(), &create_unverifiable_block(0, H256::zero()), db.clone(), Spec::new_null().engine);
 
 	GuardedTempResult::<BlockChain> {
 		_temp: temp,