neoneo-go/pkg/core/block/block.go
Roman Khimov 5616585697 block/dao: simplify trimming, avoid allocations
The only user of (*Block).Trim() is in DAO and it already has a nice buffer
usually, so creating another one makes no sense. It also simplifies error
handling a lot.
2022-03-18 10:49:25 +03:00

213 lines
5.7 KiB
Go

package block
import (
"encoding/json"
"errors"
"math"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/util"
)
const (
// MaxTransactionsPerBlock is the maximum number of transactions per block.
MaxTransactionsPerBlock = math.MaxUint16
)
// ErrMaxContentsPerBlock is returned when the maximum number of contents per block is reached.
var ErrMaxContentsPerBlock = errors.New("the number of contents exceeds the maximum number of contents per block")
var expectedHeaderSizeWithEmptyWitness int
func init() {
expectedHeaderSizeWithEmptyWitness = io.GetVarSize(new(Header))
}
// Block represents one block in the chain.
type Block struct {
// The base of the block.
Header
// Transaction list.
Transactions []*transaction.Transaction
// True if this block is created from trimmed data.
Trimmed bool
}
// auxBlockOut is used for JSON i/o.
type auxBlockOut struct {
Transactions []*transaction.Transaction `json:"tx"`
}
// auxBlockIn is used for JSON i/o.
type auxBlockIn struct {
Transactions []json.RawMessage `json:"tx"`
}
// ComputeMerkleRoot computes Merkle tree root hash based on actual block's data.
func (b *Block) ComputeMerkleRoot() util.Uint256 {
hashes := make([]util.Uint256, len(b.Transactions))
for i, tx := range b.Transactions {
hashes[i] = tx.Hash()
}
return hash.CalcMerkleRoot(hashes)
}
// RebuildMerkleRoot rebuilds the merkleroot of the block.
func (b *Block) RebuildMerkleRoot() {
b.MerkleRoot = b.ComputeMerkleRoot()
}
// NewTrimmedFromReader 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 NewTrimmedFromReader(stateRootEnabled bool, br *io.BinReader) (*Block, error) {
block := &Block{
Header: Header{
StateRootEnabled: stateRootEnabled,
},
Trimmed: true,
}
block.Header.DecodeBinary(br)
lenHashes := br.ReadVarUint()
if lenHashes > MaxTransactionsPerBlock {
return nil, ErrMaxContentsPerBlock
}
if lenHashes > 0 {
block.Transactions = make([]*transaction.Transaction, lenHashes)
for i := 0; i < int(lenHashes); i++ {
var hash util.Uint256
hash.DecodeBinary(br)
block.Transactions[i] = transaction.NewTrimmedTX(hash)
}
}
return block, br.Err
}
// New creates a new blank block with proper state root setting.
func New(stateRootEnabled bool) *Block {
return &Block{
Header: Header{
StateRootEnabled: stateRootEnabled,
},
}
}
// EncodeTrimmed writes trimmed representation of the block data into w. Trimmed blocks
// do not store complete transactions, instead they only store their hashes.
func (b *Block) EncodeTrimmed(w *io.BinWriter) {
b.Header.EncodeBinary(w)
w.WriteVarUint(uint64(len(b.Transactions)))
for _, tx := range b.Transactions {
h := tx.Hash()
h.EncodeBinary(w)
}
}
// DecodeBinary decodes the block from the given BinReader, implementing
// Serializable interface.
func (b *Block) DecodeBinary(br *io.BinReader) {
b.Header.DecodeBinary(br)
contentsCount := br.ReadVarUint()
if contentsCount > MaxTransactionsPerBlock {
br.Err = ErrMaxContentsPerBlock
return
}
txes := make([]*transaction.Transaction, contentsCount)
for i := 0; i < int(contentsCount); i++ {
tx := &transaction.Transaction{}
tx.DecodeBinary(br)
txes[i] = tx
}
b.Transactions = txes
if br.Err != nil {
return
}
}
// EncodeBinary encodes the block to the given BinWriter, implementing
// Serializable interface.
func (b *Block) EncodeBinary(bw *io.BinWriter) {
b.Header.EncodeBinary(bw)
bw.WriteVarUint(uint64(len(b.Transactions)))
for i := 0; i < len(b.Transactions); i++ {
b.Transactions[i].EncodeBinary(bw)
}
}
// MarshalJSON implements json.Marshaler interface.
func (b Block) MarshalJSON() ([]byte, error) {
auxb, err := json.Marshal(auxBlockOut{
Transactions: b.Transactions,
})
if err != nil {
return nil, err
}
baseBytes, err := json.Marshal(b.Header)
if err != nil {
return nil, err
}
// Stitch them together.
if baseBytes[len(baseBytes)-1] != '}' || auxb[0] != '{' {
return nil, errors.New("can't merge internal jsons")
}
baseBytes[len(baseBytes)-1] = ','
baseBytes = append(baseBytes, auxb[1:]...)
return baseBytes, nil
}
// UnmarshalJSON implements json.Unmarshaler interface.
func (b *Block) UnmarshalJSON(data []byte) error {
// As Base and auxb are at the same level in json,
// do unmarshalling separately for both structs.
auxb := new(auxBlockIn)
err := json.Unmarshal(data, auxb)
if err != nil {
return err
}
err = json.Unmarshal(data, &b.Header)
if err != nil {
return err
}
if len(auxb.Transactions) != 0 {
b.Transactions = make([]*transaction.Transaction, 0, len(auxb.Transactions))
for _, txBytes := range auxb.Transactions {
tx := &transaction.Transaction{}
err = tx.UnmarshalJSON(txBytes)
if err != nil {
return err
}
b.Transactions = append(b.Transactions, tx)
}
}
return nil
}
// GetExpectedBlockSize returns expected block size which should be equal to io.GetVarSize(b).
func (b *Block) GetExpectedBlockSize() int {
var transactionsSize int
for _, tx := range b.Transactions {
transactionsSize += tx.Size()
}
return b.GetExpectedBlockSizeWithoutTransactions(len(b.Transactions)) + transactionsSize
}
// GetExpectedBlockSizeWithoutTransactions returns expected block size without transactions size.
func (b *Block) GetExpectedBlockSizeWithoutTransactions(txCount int) int {
size := expectedHeaderSizeWithEmptyWitness - 1 - 1 + // 1 is for the zero-length (new(Header)).Script.Invocation/Verification
io.GetVarSize(&b.Script) +
io.GetVarSize(txCount)
if b.StateRootEnabled {
size += util.Uint256Size
}
return size
}