package block import ( "encoding/json" "errors" "github.com/Workiva/go-datastructures/queue" "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" ) // Block represents one block in the chain. type Block struct { // The base of the block. Base // Primary index and nonce ConsensusData ConsensusData `json:"consensus_data"` // Transaction list. Transactions []*transaction.Transaction // True if this block is created from trimmed data. Trimmed bool } // auxBlock is used for JSON i/o. type auxBlock struct { ConsensusData ConsensusData `json:"consensus_data"` Transactions []*transaction.Transaction `json:"tx"` } // Header returns the Header of the Block. func (b *Block) Header() *Header { return &Header{ Base: b.Base, } } // computeMerkleTree computes Merkle tree based on actual block's data. func (b *Block) computeMerkleTree() (*hash.MerkleTree, error) { hashes := make([]util.Uint256, len(b.Transactions)+1) hashes[0] = b.ConsensusData.Hash() for i, tx := range b.Transactions { hashes[i+1] = tx.Hash() } return hash.NewMerkleTree(hashes) } // RebuildMerkleRoot rebuilds the merkleroot of the block. func (b *Block) RebuildMerkleRoot() error { merkle, err := b.computeMerkleTree() if err != nil { return err } b.MerkleRoot = merkle.Root() return nil } // Verify verifies the integrity of the block. func (b *Block) Verify() error { if b.Transactions != nil { hashes := map[util.Uint256]bool{} for _, tx := range b.Transactions { if !hashes[tx.Hash()] { hashes[tx.Hash()] = true } else { return errors.New("transaction duplication is not allowed") } } } merkle, err := b.computeMerkleTree() 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) _ = br.ReadB() block.Script.DecodeBinary(br) lenHashes := br.ReadVarUint() if lenHashes > 0 { var consensusDataHash util.Uint256 consensusDataHash.DecodeBinary(br) lenTX := lenHashes - 1 block.Transactions = make([]*transaction.Transaction, lenTX) for i := 0; i < int(lenTX); i++ { var hash util.Uint256 hash.DecodeBinary(br) block.Transactions[i] = transaction.NewTrimmedTX(hash) } block.ConsensusData.DecodeBinary(br) } 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.WriteB(1) b.Script.EncodeBinary(buf.BinWriter) buf.WriteVarUint(uint64(len(b.Transactions)) + 1) hash := b.ConsensusData.Hash() hash.EncodeBinary(buf.BinWriter) for _, tx := range b.Transactions { h := tx.Hash() h.EncodeBinary(buf.BinWriter) } b.ConsensusData.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.Base.DecodeBinary(br) contentsCount := br.ReadVarUint() if contentsCount == 0 { br.Err = errors.New("invalid block format") return } b.ConsensusData.DecodeBinary(br) txes := make([]*transaction.Transaction, contentsCount-1) for i := 0; i < int(contentsCount)-1; i++ { tx := new(transaction.Transaction) tx.DecodeBinary(br) txes[i] = tx } b.Transactions = txes br.Err = b.Verify() } // EncodeBinary encodes the block to the given BinWriter, implementing // Serializable interface. func (b *Block) EncodeBinary(bw *io.BinWriter) { b.Base.EncodeBinary(bw) bw.WriteVarUint(uint64(len(b.Transactions) + 1)) b.ConsensusData.EncodeBinary(bw) for i := 0; i < len(b.Transactions); i++ { b.Transactions[i].EncodeBinary(bw) } } // 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 } } // MarshalJSON implements json.Marshaler interface. func (b Block) MarshalJSON() ([]byte, error) { auxb, err := json.Marshal(auxBlock{ ConsensusData: b.ConsensusData, Transactions: b.Transactions, }) if err != nil { return nil, err } baseBytes, err := json.Marshal(b.Base) 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(auxBlock) err := json.Unmarshal(data, auxb) if err != nil { return err } base := new(Base) err = json.Unmarshal(data, base) if err != nil { return err } b.Base = *base b.Transactions = auxb.Transactions b.ConsensusData = auxb.ConsensusData return nil }