package payload import ( "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 ( maxExtensibleCategorySize = 32 maxExtensibleDataSize = math.MaxUint16 ) // Extensible represents payload containing arbitrary data. type Extensible struct { // Category is payload type. Category string // ValidBlockStart is starting height for payload to be valid. ValidBlockStart uint32 // ValidBlockEnd is height after which payload becomes invalid. ValidBlockEnd uint32 // Sender is payload sender or signer. Sender util.Uint160 // Data is custom payload data. Data []byte // Witness is payload witness. Witness transaction.Witness hash util.Uint256 } var errInvalidPadding = errors.New("invalid padding") // NewExtensible creates new extensible payload. func NewExtensible() *Extensible { return &Extensible{} } func (e *Extensible) encodeBinaryUnsigned(w *io.BinWriter) { w.WriteString(e.Category) w.WriteU32LE(e.ValidBlockStart) w.WriteU32LE(e.ValidBlockEnd) w.WriteBytes(e.Sender[:]) w.WriteVarBytes(e.Data) } // EncodeBinary implements io.Serializable. func (e *Extensible) EncodeBinary(w *io.BinWriter) { e.encodeBinaryUnsigned(w) w.WriteB(1) e.Witness.EncodeBinary(w) } func (e *Extensible) decodeBinaryUnsigned(r *io.BinReader) { e.Category = r.ReadString(maxExtensibleCategorySize) e.ValidBlockStart = r.ReadU32LE() e.ValidBlockEnd = r.ReadU32LE() r.ReadBytes(e.Sender[:]) e.Data = r.ReadVarBytes(MaxSize) } // DecodeBinary implements io.Serializable. func (e *Extensible) DecodeBinary(r *io.BinReader) { e.decodeBinaryUnsigned(r) if r.ReadB() != 1 { if r.Err != nil { return } r.Err = errInvalidPadding return } e.Witness.DecodeBinary(r) } // Hash returns payload hash. func (e *Extensible) Hash() util.Uint256 { if e.hash.Equals(util.Uint256{}) { e.createHash() } return e.hash } // createHash creates hashes of the payload. func (e *Extensible) createHash() { buf := io.NewBufBinWriter() e.encodeBinaryUnsigned(buf.BinWriter) e.hash = hash.Sha256(buf.Bytes()) }