add node create blocks from pending txs

core/block.go

@@ -43,6 +43,20 @@ type Block struct {
 	Signature []byte
 }
 
+func (block Block) Copy() *Block {
+	return &Block{
+		Height:    block.Height,
+		PrevHash:  block.PrevHash,
+		NextHash:  block.NextHash,
+		Txs:       block.Txs,
+		Miner:     block.Miner,
+		Timestamp: block.Timestamp,
+		Nonce:     block.Nonce,
+		Hash:      block.Hash,
+		Signature: block.Signature,
+	}
+}
+
 // Bytes outputs a byte array containing the data of the Block
 func (blk Block) Bytes() []byte {
 	b, _ := json.Marshal(blk)
@@ -56,16 +70,25 @@ func (blk *Block) GetNonce() uint64 {
 func (blk *Block) IncrementNonce() {
 	blk.Nonce++
 }
-func (block *Block) CalculatePoW(difficulty int) error {
-	hash := HashBytes(block.Bytes())
+func (block *Block) CalculatePoW(difficulty uint64) error {
+	blockCopy := block.Copy()
+	blockCopy.Hash = Hash{}
+
+	hash := HashBytes(blockCopy.Bytes())
 	for !CheckPoW(hash, difficulty) {
-		block.IncrementNonce()
-		hash = HashBytes(block.Bytes())
+		blockCopy.IncrementNonce()
+		hash = HashBytes(blockCopy.Bytes())
 	}
 	block.Hash = hash
 	return nil
 }
 
+func CheckBlockPoW(block *Block, difficulty uint64) bool {
+	blockCopy := block.Copy()
+	blockCopy.Hash = Hash{}
+	return CheckPoW(HashBytes(blockCopy.Bytes()), difficulty)
+}
+
 func BlockFromBytes(b []byte) (*Block, error) {
 	var block *Block
 	err := json.Unmarshal(b, &block)

core/block_test.go

@@ -18,11 +18,14 @@ func TestBlock(t *testing.T) {
 		Hash:      HashBytes([]byte("blockhash")),
 	}
 
-	block, err := BlockFromBytes(block.Bytes())
+	blockParsed, err := BlockFromBytes(block.Bytes())
 	assert.Nil(t, err)
-	assert.Equal(t, block.Bytes(), block.Bytes())
+	assert.Equal(t, blockParsed.Bytes(), block.Bytes())
 
-	difficulty := 2
+	blockCopy := block.Copy()
+	assert.Equal(t, blockCopy.Bytes(), block.Bytes())
+
+	difficulty := uint64(2)
 	nonce, err := CalculatePoW(block, difficulty)
 	assert.Nil(t, err)
 	block.Nonce = nonce
@@ -47,7 +50,7 @@ func TestNewBlock(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, block2.Bytes(), block.Bytes())
 
-	difficulty := 2
+	difficulty := uint64(2)
 	nonce, err := CalculatePoW(block, difficulty)
 	assert.Nil(t, err)
 	block.Nonce = nonce

core/blockchain.go

@@ -8,18 +8,20 @@ import (
 )
 
 type Blockchain struct {
-	Id        []byte // Id allows to have multiple blockchains
-	Genesis   Hash
-	LastBlock *Block
-	db        *db.Db
+	Id         []byte // Id allows to have multiple blockchains
+	Difficulty uint64
+	Genesis    Hash
+	LastBlock  *Block
+	db         *db.Db
 }
 
-func NewBlockchain(database *db.Db) *Blockchain {
+func NewBlockchain(database *db.Db, dif uint64) *Blockchain {
 	blockchain := &Blockchain{
-		Id:        []byte{},
-		Genesis:   Hash{},
-		LastBlock: &Block{},
-		db:        database,
+		Id:         []byte{},
+		Difficulty: dif,
+		Genesis:    HashBytes([]byte("genesis")),
+		LastBlock:  &Block{},
+		db:         database,
 	}
 	return blockchain
 }

core/blockchain_test.go

@@ -14,7 +14,7 @@ func TestBlockchainDataStructure(t *testing.T) {
 	db, err := db.New(dir)
 	assert.Nil(t, err)
 
-	bc := NewBlockchain(db)
+	bc := NewBlockchain(db, uint64(1))
 	block := bc.NewBlock([]Tx{})
 
 	block2, err := BlockFromBytes(block.Bytes())
@@ -28,7 +28,7 @@ func TestGetBlock(t *testing.T) {
 	db, err := db.New(dir)
 	assert.Nil(t, err)
 
-	bc := NewBlockchain(db)
+	bc := NewBlockchain(db, uint64(1))
 
 	block := bc.NewBlock([]Tx{})
 	assert.Equal(t, block.Height, uint64(1))
@@ -47,12 +47,11 @@ func TestGetPrevBlock(t *testing.T) {
 	db, err := db.New(dir)
 	assert.Nil(t, err)
 
-	difficulty := 1
-	bc := NewBlockchain(db)
+	bc := NewBlockchain(db, uint64(1))
 
 	for i := 0; i < 10; i++ {
 		block := bc.NewBlock([]Tx{})
-		block.CalculatePoW(difficulty)
+		block.CalculatePoW(bc.Difficulty)
 		assert.Equal(t, block.Height, uint64(i+1))
 
 		err = bc.AddBlock(block)
@@ -83,7 +82,7 @@ func TestAddBlockWithTx(t *testing.T) {
 	db, err := db.New(dir)
 	assert.Nil(t, err)
 
-	bc := NewBlockchain(db)
+	bc := NewBlockchain(db, uint64(1))
 
 	var txs []Tx
 	tx := NewTx(addr0, addr1, []Input{}, []Output{})

core/common.go

@@ -31,7 +31,7 @@ type PoWData interface {
 }
 
 // CheckPoW verifies the PoW difficulty of a Hash
-func CheckPoW(hash Hash, difficulty int) bool {
+func CheckPoW(hash Hash, difficulty uint64) bool {
 	var empty [32]byte
 	if !bytes.Equal(hash[:][0:difficulty], empty[0:difficulty]) {
 		return false
@@ -40,7 +40,7 @@ func CheckPoW(hash Hash, difficulty int) bool {
 }
 
 // CalculatePoW calculates the nonce for the given data in order to fit in the current Proof of Work difficulty
-func CalculatePoW(data PoWData, difficulty int) (uint64, error) {
+func CalculatePoW(data PoWData, difficulty uint64) (uint64, error) {
 	hash := HashBytes(data.Bytes())
 	for !CheckPoW(hash, difficulty) {
 		data.IncrementNonce()

core/common_test.go

@@ -36,7 +36,7 @@ func (d *testData) IncrementNonce() {
 }
 
 func TestPoW(t *testing.T) {
-	difficulty := 2
+	difficulty := uint64(2)
 	data := &testData{
 		Data:  []byte("test"),
 		Nonce: 0,

core/keys.go

@@ -45,9 +45,9 @@ func AddressFromPrivK(privK *ecdsa.PrivateKey) Address {
 	return Address(h)
 }
 
-func (sig *Signature) Bytes(r, s *big.Int) []byte {
-	b := r.Bytes()
-	b = append(b, s.Bytes()...)
+func (sig *Signature) Bytes() []byte {
+	b := sig.R.Bytes()
+	b = append(b, sig.S.Bytes()...)
 	return b
 }
 

node/node.go

@@ -8,19 +8,20 @@ import (
 )
 
 type Node struct {
-	PrivK *ecdsa.PrivateKey
-	Addr  core.Address
-	Bc    *core.Blockchain
+	PrivK      *ecdsa.PrivateKey
+	Addr       core.Address
+	Bc         *core.Blockchain
+	PendingTxs []core.Tx
 }
 
-func NewNode(db *db.Db) (*Node, error) {
+func NewNode(db *db.Db, dif uint64) (*Node, error) {
 	privK, err := core.NewKey()
 	if err != nil {
 		return nil, err
 	}
 	addr := core.AddressFromPrivK(privK)
 
-	bc := core.NewBlockchain(db)
+	bc := core.NewBlockchain(db, dif)
 
 	node := &Node{
 		PrivK: privK,
@@ -33,3 +34,21 @@ func NewNode(db *db.Db) (*Node, error) {
 func (node *Node) Sign(m []byte) (*core.Signature, error) {
 	return core.Sign(node.PrivK, m)
 }
+
+func (node *Node) AddToPendingTxs(tx core.Tx) {
+	node.PendingTxs = append(node.PendingTxs, tx)
+}
+
+func (node *Node) BlockFromPendingTxs() (*core.Block, error) {
+	block := node.Bc.NewBlock(node.PendingTxs)
+	err := block.CalculatePoW(node.Bc.Difficulty)
+	if err != nil {
+		return nil, err
+	}
+	sig, err := node.Sign(block.Bytes())
+	if err != nil {
+		return nil, err
+	}
+	block.Signature = sig.Bytes()
+	return block, nil
+}

node/node_test.go

@@ -15,7 +15,7 @@ func TestNode(t *testing.T) {
 	db, err := db.New(dir)
 	assert.Nil(t, err)
 
-	node, err := NewNode(db)
+	node, err := NewNode(db, uint64(1))
 	assert.Nil(t, err)
 
 	assert.Equal(t, node.Addr, core.AddressFromPrivK(node.PrivK))
@@ -27,7 +27,7 @@ func TestNodeSignature(t *testing.T) {
 	db, err := db.New(dir)
 	assert.Nil(t, err)
 
-	node, err := NewNode(db)
+	node, err := NewNode(db, uint64(1))
 	assert.Nil(t, err)
 
 	m := []byte("test")
@@ -36,3 +36,38 @@ func TestNodeSignature(t *testing.T) {
 	pubK := node.PrivK.PublicKey
 	assert.True(t, core.VerifySignature(&pubK, m, *sig))
 }
+
+func TestBlockFromPendingTxs(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	db, err := db.New(dir)
+	assert.Nil(t, err)
+
+	node, err := NewNode(db, uint64(1))
+	assert.Nil(t, err)
+
+	addr0 := core.Address(core.HashBytes([]byte("addr0")))
+	addr1 := core.Address(core.HashBytes([]byte("addr1")))
+	tx := core.NewTx(addr0, addr1, []core.Input{}, []core.Output{})
+	node.AddToPendingTxs(*tx)
+	block, err := node.BlockFromPendingTxs()
+	assert.True(t, core.CheckBlockPoW(block, node.Bc.Difficulty))
+	// TODO add VerifyBlockSignature
+}
+
+// func TestBlockFromPendingTxsIteration(t *testing.T) {
+//         dir, err := ioutil.TempDir("", "db")
+//         assert.Nil(t, err)
+//         db, err := db.New(dir)
+//         assert.Nil(t, err)
+//
+//         node, err := NewNode(db, uint64(1))
+//         assert.Nil(t, err)
+//
+//         addr0 := core.Address(core.HashBytes([]byte("addr0")))
+//         addr1 := core.Address(core.HashBytes([]byte("addr1")))
+//         for i := 0; i < 10; i++ {
+//                 tx := core.NewTx(addr0, addr1, []core.Input{}, []core.Output{})
+//
+//         }
+// }