Link new block after consensus into blockchain

blockchain/block.go

@@ -14,7 +14,7 @@ type Block struct {
 	Timestamp     int64
 	Transactions  []*Transaction
 	PrevBlockHash []byte
-	Hash          []byte
+	Hash          [32]byte
 }
 
 // Serialize serializes the block
@@ -64,8 +64,9 @@ func (b *Block) HashTransactions() []byte {
 
 // NewBlock creates and returns a neew block.
 func NewBlock(transactions []*Transaction, prevBlockHash []byte) *Block {
-	block := &Block{time.Now().Unix(), transactions, prevBlockHash, []byte{}}
-	block.Hash = block.HashTransactions()
+	block := &Block{time.Now().Unix(), transactions, prevBlockHash, [32]byte{}}
+	copy(block.Hash[:], block.HashTransactions()[:]) // TODO(Minh): the blockhash should be a hash of everything in the block
+
 	return block
 }
 

blockchain/block_test.go

@@ -23,7 +23,7 @@ func TestBlockSerialize(t *testing.T) {
 		t.Errorf("Serialize or Deserialize incorrect at PrevBlockHash.")
 	}
 
-	if bytes.Compare(block.Hash, deserializedBlock.Hash) != 0 {
+	if bytes.Compare(block.Hash[:], deserializedBlock.Hash[:]) != 0 {
 		t.Errorf("Serialize or Deserialize incorrect at Hash.")
 	}
 }

blockchain/blockchain.go

@@ -12,6 +12,13 @@ type Blockchain struct {
 
 const genesisCoinbaseData = "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
 
+func (bc *Blockchain) GetLatestBlock() *Block{
+	if len(bc.Blocks) == 0 {
+		return nil
+	}
+	return bc.Blocks[len(bc.Blocks) - 1]
+}
+
 // FindUnspentTransactions returns a list of transactions containing unspent outputs
 func (bc *Blockchain) FindUnspentTransactions(address string) []Transaction {
 	var unspentTXs []Transaction
@@ -135,7 +142,7 @@ func (bc *Blockchain) NewUTXOTransaction(from, to string, amount int) *Transacti
 func (bc *Blockchain) AddNewUserTransfer(utxoPool *UTXOPool, from, to string, amount int) bool {
 	tx := bc.NewUTXOTransaction(from, to, amount)
 	if tx != nil {
-		newBlock := NewBlock([]*Transaction{tx}, bc.Blocks[len(bc.Blocks)-1].Hash)
+		newBlock := NewBlock([]*Transaction{tx}, bc.Blocks[len(bc.Blocks)-1].Hash[:])
 		if bc.VerifyNewBlockAndUpdate(utxoPool, newBlock) {
 			return true
 		}
@@ -146,7 +153,7 @@ func (bc *Blockchain) AddNewUserTransfer(utxoPool *UTXOPool, from, to string, am
 // VerifyNewBlockAndUpdate verifies if the new coming block is valid for the current blockchain.
 func (bc *Blockchain) VerifyNewBlockAndUpdate(utxopool *UTXOPool, block *Block) bool {
 	length := len(bc.Blocks)
-	if bytes.Compare(block.PrevBlockHash, bc.Blocks[length-1].Hash) != 0 {
+	if bytes.Compare(block.PrevBlockHash, bc.Blocks[length-1].Hash[:]) != 0 {
 		return false
 	}
 	if block.Timestamp < bc.Blocks[length-1].Timestamp {

blockchain/blockchain_test.go

@@ -68,7 +68,7 @@ func TestVerifyNewBlock(t *testing.T) {
 	if tx == nil {
 		t.Error("failed to create a new transaction.")
 	}
-	newBlock := NewBlock([]*Transaction{tx}, bc.Blocks[len(bc.Blocks)-1].Hash)
+	newBlock := NewBlock([]*Transaction{tx}, bc.Blocks[len(bc.Blocks)-1].Hash[:])
 
 	if !bc.VerifyNewBlockAndUpdate(utxoPool, newBlock) {
 		t.Error("failed to add a new valid block.")

blockchain/utxopool.go

@@ -212,7 +212,7 @@ func CreateUTXOPoolFromGenesisBlockChain(bc *Blockchain) *UTXOPool {
 func (utxoPool *UTXOPool) SelectTransactionsForNewBlock(transactions []*Transaction) ([]*Transaction, []*Transaction) {
 	selected, unselected := []*Transaction{}, []*Transaction{}
 	for _, tx := range transactions {
-		if len(selected) < MaxNumberOfTransactions && utxoPool.VerifyOneTransactionAndUpdate(tx) {
+		if len(selected) < MaxNumberOfTransactions && utxoPool.VerifyOneTransaction(tx) {
 			selected = append(selected, tx)
 		} else {
 			unselected = append(unselected, tx)

node/node_handler.go

@@ -118,19 +118,29 @@ func getFixedByteTxId(txId []byte) [32]byte {
 func (node *Node) WaitForConsensusReady(readySignal chan int) {
 	node.log.Debug("Waiting for consensus ready", "node", node)
 
+	var newBlock *blockchain.Block
 	for { // keep waiting for consensus ready
 		<-readySignal
-		// create a new block
-		newBlock := new(blockchain.Block)
+		//node.log.Debug("Adding new block", "currentChainSize", len(node.blockchain.Blocks), "numTxs", len(node.blockchain.GetLatestBlock().Transactions), "PrevHash", node.blockchain.GetLatestBlock().PrevBlockHash, "Hash", node.blockchain.GetLatestBlock().Hash)
+		if newBlock != nil {
+			// Consensus is done on the previous newBlock, add it to blockchain
+			node.blockchain.Blocks = append(node.blockchain.Blocks, newBlock)
+			// Update UTXO pool
+			node.UtxoPool.Update(node.transactionInConsensus)
+			// Clear transaction in consensus slice
+			node.transactionInConsensus = []*blockchain.Transaction{}
+		}
 		for {
 			if len(node.pendingTransactions) >= 10 {
 				selectedTxs := node.getTransactionsForNewBlock()
+
 				if len(selectedTxs) == 0 {
 					node.log.Debug("No transactions is selected for consensus", "pendingTx", len(node.pendingTransactions))
 				} else {
-					node.log.Debug("Creating new block", "numTxs", len(selectedTxs), "pendingTxs", len(node.pendingTransactions))
+					node.log.Debug("Creating new block", "numTxs", len(selectedTxs), "pendingTxs", len(node.pendingTransactions), "currentChainSize", len(node.blockchain.Blocks))
 
-					newBlock = blockchain.NewBlock(selectedTxs, []byte{})
+					node.transactionInConsensus = selectedTxs
+					newBlock = blockchain.NewBlock(selectedTxs, node.blockchain.GetLatestBlock().Hash[:])
 					break
 				}
 			}