add verify_transactions and update utxo

blockchain/block_test.go

@@ -6,7 +6,10 @@ import (
 )
 
 func TestBlockSerialize(t *testing.T) {
-	cbtx := NewCoinbaseTX("minh", genesisCoinbaseData)
+	cbtx, utxoPool := NewCoinbaseTX("minh", genesisCoinbaseData)
+	if cbtx == nil || utxoPool == nil {
+		t.Errorf("Failed to create a coinbase transaction.")
+	}
 	block := NewGenesisBlock(cbtx)
 
 	serializedValue := block.Serialize()

blockchain/blockchain.go

@@ -3,6 +3,7 @@ package blockchain
 import (
 	"bytes"
 	"encoding/hex"
+	"fmt"
 )
 
 // Blockchain keeps a sequence of Blocks
@@ -130,20 +131,21 @@ func (bc *Blockchain) NewUTXOTransaction(from, to string, amount int) *Transacti
 	return &tx
 }
 
-// AddNewTransferAmount creates a new transaction and a block of that transaction.
+// AddNewUserTransfer creates a new transaction and a block of that transaction.
 // Mostly used for testing.
-func (bc *Blockchain) AddNewTransferAmount(from, to string, amount int) *Blockchain {
+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)
-		bc.blocks = append(bc.blocks, newBlock)
-		return bc
+		if bc.VerifyNewBlockAndUpdate(utxoPool, newBlock) {
+			return true
+		}
 	}
-	return nil
+	return false
 }
 
-// VerifyNewBlock verifies if the new coming block is valid for the current blockchain.
-func (bc *Blockchain) VerifyNewBlock(utxopool *UTXOPool, block *Block) bool {
+// 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 {
 		return false
@@ -152,40 +154,21 @@ func (bc *Blockchain) VerifyNewBlock(utxopool *UTXOPool, block *Block) bool {
 		return false
 	}
 
-	if utxopool != nil {
-		for _, tx := range block.Transactions {
-			inTotal := 0
-			// Calculate the sum of TxInput
-			for _, in := range tx.TxInput {
-				inTxID := hex.EncodeToString(in.TxID)
-				if val, ok := utxopool.utxo[in.Address][inTxID]; ok {
-					inTotal += val
-				} else {
-					return false
-				}
-			}
-
-			outTotal := 0
-			// Calculate the sum of TxOutput
-			for _, out := range tx.TxOutput {
-				outTotal += out.Value
-			}
-			if inTotal != outTotal {
-				return false
-			}
-		}
+	if utxopool != nil && !utxopool.VerifyAndUpdate(block.Transactions) {
+		fmt.Println("Minh2")
+		return false
 	}
 	return true
 }
 
 // CreateBlockchain creates a new blockchain DB
-func CreateBlockchain(address string) *Blockchain {
+func CreateBlockchain(address string) (*Blockchain, *UTXOPool) {
 	// TODO: We assume we have not created any blockchain before.
 	// In current bitcoin, we can check if we created a blockchain before accessing local db.
-	cbtx := NewCoinbaseTX(address, genesisCoinbaseData)
+	cbtx, utxoPool := NewCoinbaseTX(address, genesisCoinbaseData)
 	genesis := NewGenesisBlock(cbtx)
 
 	bc := Blockchain{[]*Block{genesis}}
 
-	return &bc
+	return &bc, utxoPool
 }

blockchain/blockchain_test.go

@@ -5,14 +5,14 @@ import (
 )
 
 func TestCreateBlockchain(t *testing.T) {
-	if CreateBlockchain("minh") == nil {
+	if bc, _ := CreateBlockchain("minh"); bc == nil {
 		t.Errorf("failed to create a blockchain")
 	}
 }
 
 func TestFindSpendableOutputs(t *testing.T) {
 	requestAmount := 3
-	bc := CreateBlockchain("minh")
+	bc, _ := CreateBlockchain("minh")
 	accumulated, unspentOutputs := bc.FindSpendableOutputs("minh", requestAmount)
 	if accumulated < DefaultCoinbaseValue {
 		t.Error("Failed to find enough unspent ouptuts")
@@ -24,7 +24,7 @@ func TestFindSpendableOutputs(t *testing.T) {
 }
 
 func TestFindUTXO(t *testing.T) {
-	bc := CreateBlockchain("minh")
+	bc, _ := CreateBlockchain("minh")
 	utxo := bc.FindUTXO("minh")
 
 	total := 0
@@ -40,32 +40,26 @@ func TestFindUTXO(t *testing.T) {
 	}
 }
 
-func TestAddNewTransferAmount(t *testing.T) {
-	bc := CreateBlockchain("minh")
+func TestAddNewUserTransfer(t *testing.T) {
+	bc, utxoPool := CreateBlockchain("minh")
 
-	bc = bc.AddNewTransferAmount("minh", "alok", 3)
-
-	if bc == nil {
-		t.Error("Failed to add new transfer to alok")
+	if !bc.AddNewUserTransfer(utxoPool, "minh", "alok", 3) {
+		t.Error("Failed to add new transfer to alok.")
 	}
 
-	bc = bc.AddNewTransferAmount("minh", "rj", 100)
-
-	if bc == nil {
-		t.Error("Failed to add new transfer to rj")
+	if !bc.AddNewUserTransfer(utxoPool, "minh", "rj", 100) {
+		t.Error("Failed to add new transfer to rj.")
 	}
 
-	bc = bc.AddNewTransferAmount("minh", "stephen", DefaultCoinbaseValue-102)
-
-	if bc != nil {
-		t.Error("minh should not have enough fun to make the transfer")
+	if bc.AddNewUserTransfer(utxoPool, "minh", "stephen", DefaultCoinbaseValue-102) {
+		t.Error("minh should not have enough fun to make the transfer.")
 	}
 }
 
 func TestVerifyNewBlock(t *testing.T) {
-	bc := CreateBlockchain("minh")
-	bc = bc.AddNewTransferAmount("minh", "alok", 3)
-	bc = bc.AddNewTransferAmount("minh", "rj", 100)
+	bc, utxoPool := CreateBlockchain("minh")
+	bc.AddNewUserTransfer(utxoPool, "minh", "alok", 3)
+	bc.AddNewUserTransfer(utxoPool, "minh", "rj", 100)
 
 	tx := bc.NewUTXOTransaction("minh", "mark", 10)
 	if tx == nil {
@@ -73,7 +67,7 @@ func TestVerifyNewBlock(t *testing.T) {
 	}
 	newBlock := NewBlock([]*Transaction{tx}, bc.blocks[len(bc.blocks)-1].Hash)
 
-	if !bc.VerifyNewBlock(nil, newBlock) {
+	if !bc.VerifyNewBlockAndUpdate(utxoPool, newBlock) {
 		t.Error("failed to add a new valid block.")
 	}
 }

blockchain/transaction.go

@@ -47,7 +47,7 @@ func (tx *Transaction) SetID() {
 }
 
 // NewCoinbaseTX creates a new coinbase transaction
-func NewCoinbaseTX(to, data string) *Transaction {
+func NewCoinbaseTX(to, data string) (*Transaction, *UTXOPool) {
 	if data == "" {
 		data = fmt.Sprintf("Reward to '%s'", to)
 	}
@@ -56,8 +56,14 @@ func NewCoinbaseTX(to, data string) *Transaction {
 	txout := TXOutput{DefaultCoinbaseValue, to}
 	tx := Transaction{nil, []TXInput{txin}, []TXOutput{txout}}
 	tx.SetID()
+	txID := hex.EncodeToString(tx.ID)
 
-	return &tx
+	var utxoPool UTXOPool
+	utxoPool.utxo = make(map[string]map[string]int)
+	utxoPool.utxo[to] = make(map[string]int)
+	utxoPool.utxo[to][txID] = DefaultCoinbaseValue
+
+	return &tx, &utxoPool
 }
 
 // Used for debuging.

blockchain/transaction_test.go

@@ -5,7 +5,7 @@ import (
 )
 
 func TestNewCoinbaseTX(t *testing.T) {
-	if NewCoinbaseTX("minh", genesisCoinbaseData) == nil {
+	if cbtx, utxoPool := NewCoinbaseTX("minh", genesisCoinbaseData); cbtx == nil || utxoPool == nil {
 		t.Errorf("failed to create a coinbase transaction.")
 	}
 }

blockchain/utxopool.go

@@ -1,8 +1,88 @@
 package blockchain
 
+import "encoding/hex"
+
 // UTXOPool stores transactions and balance associated with each address.
 type UTXOPool struct {
 	// Mapping from address to a map of transaction id to that balance.
 	// The assumption here is that one address only appears once output array in a transaction.
 	utxo map[string]map[string]int
 }
+
+// VerifyTransactions verifies if a list of transactions valid.
+func (utxopool *UTXOPool) VerifyTransactions(transactions []*Transaction) bool {
+	spentTXOs := make(map[string]map[string]bool)
+	if utxopool != nil {
+		for _, tx := range transactions {
+			inTotal := 0
+			// Calculate the sum of TxInput
+			for _, in := range tx.TxInput {
+				inTxID := hex.EncodeToString(in.TxID)
+				// Check if the transaction with the addres is spent or not.
+				if val, ok := spentTXOs[in.Address][inTxID]; ok {
+					if val {
+						return false
+					}
+				}
+				// Mark the transactions with the addres spent.
+				if _, ok := spentTXOs[in.Address]; ok {
+					spentTXOs[in.Address][inTxID] = true
+				} else {
+					spentTXOs[in.Address] = make(map[string]bool)
+					spentTXOs[in.Address][inTxID] = true
+				}
+
+				// Sum the balance up to the inTotal.
+				if val, ok := utxopool.utxo[in.Address][inTxID]; ok {
+					inTotal += val
+				} else {
+					return false
+				}
+			}
+
+			outTotal := 0
+			// Calculate the sum of TxOutput
+			for _, out := range tx.TxOutput {
+				outTotal += out.Value
+			}
+			if inTotal != outTotal {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// VerifyAndUpdate verifies a list of transactions and update utxoPool.
+func (utxopool *UTXOPool) VerifyAndUpdate(transactions []*Transaction) bool {
+	if utxopool.VerifyTransactions(transactions) {
+		utxopool.Update(transactions)
+		return true
+	}
+	return false
+}
+
+// Update utxo balances with a list of new transactions.
+func (utxopool *UTXOPool) Update(transactions []*Transaction) {
+	if utxopool != nil {
+		for _, tx := range transactions {
+			curTxID := hex.EncodeToString(tx.ID)
+
+			// Remove
+			for _, in := range tx.TxInput {
+				inTxID := hex.EncodeToString(in.TxID)
+				delete(utxopool.utxo[in.Address], inTxID)
+			}
+
+			// Update
+			for _, out := range tx.TxOutput {
+				if _, ok := utxopool.utxo[out.Address]; ok {
+					utxopool.utxo[out.Address][curTxID] = out.Value
+				} else {
+					utxopool.utxo[out.Address] = make(map[string]int)
+					utxopool.utxo[out.Address][curTxID] = out.Value
+				}
+			}
+		}
+	}
+}

blockchain/utxopool_test.go

@@ -0,0 +1,11 @@
+package blockchain
+
+import (
+	"testing"
+)
+
+func TestVerifyTransactions(t *testing.T) {
+	if cbtx, utxoPool := NewCoinbaseTX("minh", genesisCoinbaseData); cbtx == nil || utxoPool == nil {
+		t.Errorf("failed to create a coinbase transaction.")
+	}
+}