neo-go/pkg/core/block.go

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package core
import (
"errors"
"fmt"
"github.com/CityOfZion/neo-go/pkg/core/transaction"
"github.com/CityOfZion/neo-go/pkg/crypto"
"github.com/CityOfZion/neo-go/pkg/io"
"github.com/CityOfZion/neo-go/pkg/util"
"github.com/Workiva/go-datastructures/queue"
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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,
}
}
func merkleTreeFromTransactions(txes []*transaction.Transaction) (*crypto.MerkleTree, error) {
hashes := make([]util.Uint256, len(txes))
for i, tx := range txes {
hashes[i] = tx.Hash()
}
return crypto.NewMerkleTree(hashes)
}
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// rebuildMerkleRoot rebuilds the merkleroot of the block.
func (b *Block) rebuildMerkleRoot() error {
merkle, err := merkleTreeFromTransactions(b.Transactions)
if err != nil {
return err
}
b.MerkleRoot = merkle.Root()
return nil
}
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// Verify verifies the integrity of the block.
func (b *Block) Verify() error {
// There has to be some transaction inside.
if len(b.Transactions) == 0 {
return errors.New("no transactions")
}
// The first TX has to be a miner transaction.
if b.Transactions[0].Type != transaction.MinerType {
return fmt.Errorf("the first transaction is %s", b.Transactions[0].Type)
}
// If the first TX is a minerTX then all others cant.
for _, tx := range b.Transactions[1:] {
if tx.Type == transaction.MinerType {
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return fmt.Errorf("miner transaction %s is not the first one", tx.Hash().StringLE())
}
}
merkle, err := merkleTreeFromTransactions(b.Transactions)
if err != nil {
return err
}
if !b.MerkleRoot.Equals(merkle.Root()) {
return errors.New("MerkleRoot mismatch")
}
return nil
}
// 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,
}
br := io.NewBinReaderFromBuf(b)
block.decodeHashableFields(br)
var padding uint8
br.ReadLE(&padding)
block.Script.DecodeBinary(br)
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 := io.NewBufBinWriter()
b.encodeHashableFields(buf.BinWriter)
buf.WriteBytes([]byte{1})
b.Script.EncodeBinary(buf.BinWriter)
buf.WriteVarUint(uint64(len(b.Transactions)))
for _, tx := range b.Transactions {
h := tx.Hash()
h.EncodeBinary(buf.BinWriter)
}
if buf.Err != nil {
return nil, buf.Err
}
return buf.Bytes(), nil
}
// DecodeBinary decodes the block from the given BinReader, implementing
// Serializable interface.
func (b *Block) DecodeBinary(br *io.BinReader) {
b.BlockBase.DecodeBinary(br)
br.ReadArray(&b.Transactions)
}
// EncodeBinary encodes the block to the given BinWriter, implementing
// Serializable interface.
func (b *Block) EncodeBinary(bw *io.BinWriter) {
b.BlockBase.EncodeBinary(bw)
bw.WriteArray(b.Transactions)
}
// Compare implements the queue Item interface.
func (b *Block) Compare(item queue.Item) int {
other := item.(*Block)
switch {
case b.Index > other.Index:
return 1
case b.Index == other.Index:
return 0
default:
return -1
}
}