[DEV-244] Remove BlockHeader.NumParentBlocks and use a method instead (#121)

blockdag/blockindex.go

@@ -164,7 +164,6 @@ func (node *blockNode) Header() *wire.BlockHeader {
 	// No lock is needed because all accessed fields are immutable.
 	return &wire.BlockHeader{
 		Version:      node.version,
-		NumParentBlocks: byte(len(node.parents)),
 		ParentHashes: node.ParentHashes(),
 		MerkleRoot:   node.merkleRoot,
 		Timestamp:    time.Unix(node.timestamp, 0),

blockdag/fullblocktests/generate.go

@@ -510,7 +510,6 @@ func (g *testGenerator) nextBlock(blockName string, spend *spendableOut, mungers
 	block := wire.MsgBlock{
 		Header: wire.BlockHeader{
 			Version:      1,
-			NumParentBlocks: 1,                                 // TODO: (Stas) This is wrong. Modified only to satisfy compilation.
 			ParentHashes: []daghash.Hash{g.tip.BlockHash()}, // TODO: (Stas) This is wrong. Modified only to satisfy compilation.
 			MerkleRoot:   calcMerkleRoot(txns),
 			Bits:         g.params.PowLimitBits,

blockdag/fullblocktests/params.go

@@ -55,7 +55,6 @@ var (
 	regTestGenesisBlock = wire.MsgBlock{
 		Header: wire.BlockHeader{
 			Version:      1,
-			NumParentBlocks: 0,
 			ParentHashes: []daghash.Hash{},
 			MerkleRoot:   *newHashFromStr("4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"),
 			Timestamp:    time.Unix(0x5b28c636, 0), // 2018-06-19 09:00:38 +0000 UTC

blockdag/validate.go

@@ -431,7 +431,7 @@ func checkBlockHeaderSanity(header *wire.BlockHeader, powLimit *big.Int, timeSou
 
 //checkBlockParentsOrder ensures that the block's parents are ordered by hash
 func checkBlockParentsOrder(header *wire.BlockHeader) error {
-	sortedHashes := make([]daghash.Hash, 0, len(header.ParentHashes))
+	sortedHashes := make([]daghash.Hash, 0, header.NumParentBlocks())
 	for _, hash := range header.ParentHashes {
 		sortedHashes = append(sortedHashes, hash)
 	}

blockdag/validate_test.go

@@ -170,7 +170,6 @@ func TestCheckBlockSanity(t *testing.T) {
 	var invalidParentsOrderBlock = wire.MsgBlock{
 		Header: wire.BlockHeader{
 			Version: 1,
-			NumParentBlocks: 2,
 			ParentHashes: []daghash.Hash{
 				[32]byte{ // Make go vet happy.
 					0x4b, 0xb0, 0x75, 0x35, 0xdf, 0xd5, 0x8e, 0x0b,
@@ -611,7 +610,6 @@ func TestValidateParents(t *testing.T) {
 var Block100000 = wire.MsgBlock{
 	Header: wire.BlockHeader{
 		Version: 1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{
 			[32]byte{ // Make go vet happy.
 				0x16, 0x5e, 0x38, 0xe8, 0xb3, 0x91, 0x45, 0x95,

dagconfig/genesis.go

@@ -79,7 +79,6 @@ var genesisMerkleRoot = daghash.Hash([daghash.HashSize]byte{ // Make go vet happ
 var genesisBlock = wire.MsgBlock{
 	Header: wire.BlockHeader{
 		Version:      1,
-		NumParentBlocks: 0,
 		ParentHashes: []daghash.Hash{},
 		MerkleRoot:   genesisMerkleRoot,        // 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b
 		Timestamp:    time.Unix(0x5bbe076c, 0), // 2018-10-10 14:06:36 +0000 UTC
@@ -108,7 +107,6 @@ var regTestGenesisMerkleRoot = genesisMerkleRoot
 var regTestGenesisBlock = wire.MsgBlock{
 	Header: wire.BlockHeader{
 		Version:      1,
-		NumParentBlocks: 0,
 		ParentHashes: []daghash.Hash{},
 		MerkleRoot:   regTestGenesisMerkleRoot, // 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b
 		Timestamp:    time.Unix(0x5bbe0d4b, 0), // 2018-06-19 09:00:38 +0000 UTC
@@ -137,7 +135,6 @@ var testNet3GenesisMerkleRoot = genesisMerkleRoot
 var testNet3GenesisBlock = wire.MsgBlock{
 	Header: wire.BlockHeader{
 		Version:      1,
-		NumParentBlocks: 0,
 		ParentHashes: []daghash.Hash{},
 		MerkleRoot:   testNet3GenesisMerkleRoot, // 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b
 		Timestamp:    time.Unix(0x5bbe0e49, 0),  // 2018-06-19 09:04:06 +0000 UTC
@@ -166,7 +163,6 @@ var simNetGenesisMerkleRoot = genesisMerkleRoot
 var simNetGenesisBlock = wire.MsgBlock{
 	Header: wire.BlockHeader{
 		Version:      1,
-		NumParentBlocks: 0,
 		ParentHashes: []daghash.Hash{},
 		MerkleRoot:   simNetGenesisMerkleRoot,  // 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b
 		Timestamp:    time.Unix(0x5bbe00fe, 0), // 2018-10-10 13:39:10 +0000 UTC

database/testdata/generator.go

@@ -45,7 +45,6 @@ func generateBlock(parent *wire.MsgBlock) *wire.MsgBlock {
 	return &wire.MsgBlock{
 		Header: wire.BlockHeader{
 			Version:      1,
-			NumParentBlocks: 1,
 			ParentHashes: []daghash.Hash{parent.BlockHash()},
 			MerkleRoot:   genesisMerkleRoot,
 			Timestamp:    time.Unix(0x5b28c4c8, 0), // 2018-06-19 08:54:32 +0000 UTC

mining/mining.go

@@ -716,7 +716,6 @@ mempoolLoop:
 	var msgBlock wire.MsgBlock
 	msgBlock.Header = wire.BlockHeader{
 		Version:      nextBlockVersion,
-		NumParentBlocks: byte(len(g.dag.TipHashes())),
 		ParentHashes: g.dag.TipHashes(),
 		MerkleRoot:   *merkles[len(merkles)-1],
 		Timestamp:    ts,

util/block_test.go

@@ -305,7 +305,6 @@ func TestBlockErrors(t *testing.T) {
 var Block100000 = wire.MsgBlock{
 	Header: wire.BlockHeader{
 		Version: 1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{
 			[32]byte{ // Make go vet happy.
 				0x82, 0xdc, 0xbd, 0xe6, 0x88, 0x37, 0x74, 0x5b,

wire/blockheader.go

@@ -34,9 +34,6 @@ type BlockHeader struct {
 	// Version of the block.  This is not the same as the protocol version.
 	Version int32
 
-	// Number of entries in ParentHashes
-	NumParentBlocks byte
-
 	// Hashes of the parent block headers in the blockDAG.
 	ParentHashes []daghash.Hash
 
@@ -53,13 +50,18 @@ type BlockHeader struct {
 	Nonce uint64
 }
 
+// NumParentBlocks return the number of entries in ParentHashes
+func (h *BlockHeader) NumParentBlocks() byte {
+	return byte(len(h.ParentHashes))
+}
+
 // BlockHash computes the block identifier hash for the given block header.
 func (h *BlockHeader) BlockHash() daghash.Hash {
 	// Encode the header and double sha256 everything prior to the number of
 	// transactions.  Ignore the error returns since there is no way the
 	// encode could fail except being out of memory which would cause a
 	// run-time panic.
-	buf := bytes.NewBuffer(make([]byte, 0, BaseBlockHeaderPayload+len(h.ParentHashes)))
+	buf := bytes.NewBuffer(make([]byte, 0, BaseBlockHeaderPayload+h.NumParentBlocks()))
 	_ = writeBlockHeader(buf, 0, h)
 
 	return daghash.DoubleHashH(buf.Bytes())
@@ -67,7 +69,7 @@ func (h *BlockHeader) BlockHash() daghash.Hash {
 
 // SelectedParentHash returns the hash of the selected block header.
 func (h *BlockHeader) SelectedParentHash() *daghash.Hash {
-	if h.NumParentBlocks == 0 {
+	if h.NumParentBlocks() == 0 {
 		return nil
 	}
 
@@ -76,7 +78,7 @@ func (h *BlockHeader) SelectedParentHash() *daghash.Hash {
 
 // IsGenesis returns true iff this block is a genesis block
 func (h *BlockHeader) IsGenesis() bool {
-	return h.NumParentBlocks == 0
+	return h.NumParentBlocks() == 0
 }
 
 // BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
@@ -118,7 +120,7 @@ func (h *BlockHeader) Serialize(w io.Writer) error {
 // SerializeSize returns the number of bytes it would take to serialize the
 // block header.
 func (h *BlockHeader) SerializeSize() int {
-	return BaseBlockHeaderPayload + int(h.NumParentBlocks)*daghash.HashSize
+	return BaseBlockHeaderPayload + int(h.NumParentBlocks())*daghash.HashSize
 }
 
 // NewBlockHeader returns a new BlockHeader using the provided version, previous
@@ -131,7 +133,6 @@ func NewBlockHeader(version int32, parentHashes []daghash.Hash, merkleRootHash *
 	// doesn't support better.
 	return &BlockHeader{
 		Version:      version,
-		NumParentBlocks: byte(len(parentHashes)),
 		ParentHashes: parentHashes,
 		MerkleRoot:   *merkleRootHash,
 		Timestamp:    time.Unix(time.Now().Unix(), 0),
@@ -144,13 +145,14 @@ func NewBlockHeader(version int32, parentHashes []daghash.Hash, merkleRootHash *
 // decoding block headers stored to disk, such as in a database, as opposed to
 // decoding from the wire.
 func readBlockHeader(r io.Reader, pver uint32, bh *BlockHeader) error {
-	err := readElements(r, &bh.Version, &bh.NumParentBlocks)
+	var numParentBlocks byte
+	err := readElements(r, &bh.Version, &numParentBlocks)
 	if err != nil {
 		return err
 	}
 
-	bh.ParentHashes = make([]daghash.Hash, bh.NumParentBlocks)
+	bh.ParentHashes = make([]daghash.Hash, numParentBlocks)
-	for i := byte(0); i < bh.NumParentBlocks; i++ {
+	for i := byte(0); i < numParentBlocks; i++ {
 		err := readElement(r, &bh.ParentHashes[i])
 		if err != nil {
 			return err
@@ -164,6 +166,6 @@ func readBlockHeader(r io.Reader, pver uint32, bh *BlockHeader) error {
 // opposed to encoding for the wire.
 func writeBlockHeader(w io.Writer, pver uint32, bh *BlockHeader) error {
 	sec := int64(bh.Timestamp.Unix())
-	return writeElements(w, bh.Version, bh.NumParentBlocks, &bh.ParentHashes, &bh.MerkleRoot,
+	return writeElements(w, bh.Version, bh.NumParentBlocks(), &bh.ParentHashes, &bh.MerkleRoot,
 		sec, bh.Bits, bh.Nonce)
 }

wire/blockheader_test.go

@@ -56,7 +56,6 @@ func TestBlockHeaderWire(t *testing.T) {
 	bits := uint32(0x1d00ffff)
 	baseBlockHdr := &BlockHeader{
 		Version:      1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{mainNetGenesisHash, simNetGenesisHash},
 		MerkleRoot:   mainNetGenesisMerkleRoot,
 		Timestamp:    time.Unix(0x495fab29, 0), // 2009-01-03 12:15:05 -0600 CST
@@ -195,7 +194,6 @@ func TestBlockHeaderSerialize(t *testing.T) {
 	bits := uint32(0x1d00ffff)
 	baseBlockHdr := &BlockHeader{
 		Version:      1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{mainNetGenesisHash, simNetGenesisHash},
 		MerkleRoot:   mainNetGenesisMerkleRoot,
 		Timestamp:    time.Unix(0x495fab29, 0), // 2009-01-03 12:15:05 -0600 CST
@@ -275,7 +273,6 @@ func TestBlockHeaderSerializeSize(t *testing.T) {
 	timestamp := time.Unix(0x495fab29, 0) // 2009-01-03 12:15:05 -0600 CST
 	baseBlockHdr := &BlockHeader{
 		Version:      1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{mainNetGenesisHash, simNetGenesisHash},
 		MerkleRoot:   mainNetGenesisMerkleRoot,
 		Timestamp:    timestamp,
@@ -285,7 +282,6 @@ func TestBlockHeaderSerializeSize(t *testing.T) {
 
 	genesisBlockHdr := &BlockHeader{
 		Version:      1,
-		NumParentBlocks: 0,
 		ParentHashes: []daghash.Hash{},
 		MerkleRoot:   mainNetGenesisMerkleRoot,
 		Timestamp:    timestamp,
@@ -322,7 +318,6 @@ func TestIsGenesis(t *testing.T) {
 
 	baseBlockHdr := &BlockHeader{
 		Version:      1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{mainNetGenesisHash, simNetGenesisHash},
 		MerkleRoot:   mainNetGenesisMerkleRoot,
 		Timestamp:    timestamp,
@@ -331,7 +326,6 @@ func TestIsGenesis(t *testing.T) {
 	}
 	genesisBlockHdr := &BlockHeader{
 		Version:      1,
-		NumParentBlocks: 0,
 		ParentHashes: []daghash.Hash{},
 		MerkleRoot:   mainNetGenesisMerkleRoot,
 		Timestamp:    timestamp,

wire/msgblock_test.go

@@ -492,7 +492,6 @@ func TestBlockSerializeSize(t *testing.T) {
 var blockOne = MsgBlock{
 	Header: BlockHeader{
 		Version:      1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{mainNetGenesisHash, simNetGenesisHash},
 		MerkleRoot:   daghash.Hash(mainNetGenesisMerkleRoot),
 

wire/msgmerkleblock_test.go

@@ -338,7 +338,6 @@ func TestMerkleBlockOverflowErrors(t *testing.T) {
 var merkleBlockOne = MsgMerkleBlock{
 	Header: BlockHeader{
 		Version:      1,
-		NumParentBlocks: 2,
 		ParentHashes: []daghash.Hash{mainNetGenesisHash, simNetGenesisHash},
 		MerkleRoot: daghash.Hash([daghash.HashSize]byte{ // Make go vet happy.
 			0x98, 0x20, 0x51, 0xfd, 0x1e, 0x4b, 0xa7, 0x44,