neoneo-go/pkg/core/block.go

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2018-01-30 10:56:36 +00:00
package core
import (
"bytes"
"io"
"github.com/CityOfZion/neo-go/pkg/core/transaction"
"github.com/CityOfZion/neo-go/pkg/crypto"
"github.com/CityOfZion/neo-go/pkg/util"
log "github.com/sirupsen/logrus"
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)
// Block represents one block in the chain.
type Block struct {
// The base of the block.
BlockBase
// Transaction list.
Transactions []*transaction.Transaction `json:"tx"`
// True if this block is created from trimmed data.
Trimmed bool `json:"-"`
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}
// Header returns the Header of the Block.
func (b *Block) Header() *Header {
return &Header{
BlockBase: b.BlockBase,
}
}
// rebuildMerkleRoot rebuild the merkleroot of the block.
func (b *Block) rebuildMerkleRoot() error {
hashes := make([]util.Uint256, len(b.Transactions))
for i, tx := range b.Transactions {
hashes[i] = tx.Hash()
}
merkle, err := crypto.NewMerkleTree(hashes)
if err != nil {
return err
}
b.MerkleRoot = merkle.Root()
return nil
}
// Verify the integrity of the block.
func (b *Block) Verify(full bool) bool {
// The first TX has to be a miner transaction.
if b.Transactions[0].Type != transaction.MinerType {
return false
}
// If the first TX is a minerTX then all others cant.
for _, tx := range b.Transactions[1:] {
if tx.Type == transaction.MinerType {
return false
}
}
// TODO: When full is true, do a full verification.
if full {
log.Warn("full verification of blocks is not yet implemented")
}
return true
}
// NewBlockFromTrimmedBytes returns a new block from trimmed data.
// This is commonly used to create a block from stored data.
// Blocks created from trimmed data will have their Trimmed field
// set to true.
func NewBlockFromTrimmedBytes(b []byte) (*Block, error) {
block := &Block{
Trimmed: true,
}
r := bytes.NewReader(b)
if err := block.decodeHashableFields(r); err != nil {
return block, err
}
br := util.NewBinReaderFromIO(r)
var padding uint8
br.ReadLE(&padding)
if br.Err != nil {
return block, br.Err
}
block.Script = &transaction.Witness{}
if err := block.Script.DecodeBinary(r); err != nil {
return block, err
}
lenTX := br.ReadVarUint()
block.Transactions = make([]*transaction.Transaction, lenTX)
for i := 0; i < int(lenTX); i++ {
var hash util.Uint256
br.ReadLE(&hash)
block.Transactions[i] = transaction.NewTrimmedTX(hash)
}
return block, br.Err
}
// Trim returns a subset of the block data to save up space
// in storage.
// Notice that only the hashes of the transactions are stored.
func (b *Block) Trim() ([]byte, error) {
buf := new(bytes.Buffer)
if err := b.encodeHashableFields(buf); err != nil {
return nil, err
}
bw := util.NewBinWriterFromIO(buf)
bw.WriteLE(uint8(1))
if bw.Err != nil {
return nil, bw.Err
}
if err := b.Script.EncodeBinary(buf); err != nil {
return nil, err
}
bw.WriteVarUint(uint64(len(b.Transactions)))
for _, tx := range b.Transactions {
bw.WriteLE(tx.Hash())
}
if bw.Err != nil {
return nil, bw.Err
}
return buf.Bytes(), nil
}
// DecodeBinary decodes the block from the given reader.
func (b *Block) DecodeBinary(r io.Reader) error {
if err := b.BlockBase.DecodeBinary(r); err != nil {
return err
}
br := util.NewBinReaderFromIO(r)
lentx := br.ReadVarUint()
if br.Err != nil {
return br.Err
}
b.Transactions = make([]*transaction.Transaction, lentx)
for i := 0; i < int(lentx); i++ {
b.Transactions[i] = &transaction.Transaction{}
if err := b.Transactions[i].DecodeBinary(r); err != nil {
return err
}
}
return nil
}
// EncodeBinary encodes the block to the given writer.
func (b *Block) EncodeBinary(w io.Writer) error {
err := b.BlockBase.EncodeBinary(w)
if err != nil {
return err
}
bw := util.NewBinWriterFromIO(w)
bw.WriteVarUint(uint64(len(b.Transactions)))
if bw.Err != nil {
return err
}
for _, tx := range b.Transactions {
err := tx.EncodeBinary(w)
if err != nil {
return err
}
}
return nil
}