package transaction import ( "encoding/json" "errors" "fmt" "github.com/nspcc-dev/neo-go/pkg/io" ) // Attribute represents a Transaction attribute. type Attribute struct { Type AttrType Value interface { io.Serializable // toJSONMap is used for embedded json struct marshalling. // Anonymous interface fields are not considered anonymous by // json lib and marshaling Value together with type makes code // harder to follow. toJSONMap(map[string]any) } } // attrJSON is used for JSON I/O of Attribute. type attrJSON struct { Type string `json:"type"` } // DecodeBinary implements the Serializable interface. func (attr *Attribute) DecodeBinary(br *io.BinReader) { attr.Type = AttrType(br.ReadB()) switch t := attr.Type; t { case HighPriority: return case OracleResponseT: attr.Value = new(OracleResponse) case NotValidBeforeT: attr.Value = new(NotValidBefore) case ConflictsT: attr.Value = new(Conflicts) case NotaryAssistedT: attr.Value = new(NotaryAssisted) default: if t >= ReservedLowerBound && t <= ReservedUpperBound { attr.Value = new(Reserved) break } br.Err = fmt.Errorf("failed decoding TX attribute usage: 0x%2x", int(attr.Type)) return } attr.Value.DecodeBinary(br) } // EncodeBinary implements the Serializable interface. func (attr *Attribute) EncodeBinary(bw *io.BinWriter) { bw.WriteB(byte(attr.Type)) switch t := attr.Type; t { case HighPriority: case OracleResponseT, NotValidBeforeT, ConflictsT, NotaryAssistedT: attr.Value.EncodeBinary(bw) default: if t >= ReservedLowerBound && t <= ReservedUpperBound { attr.Value.EncodeBinary(bw) break } bw.Err = fmt.Errorf("failed encoding TX attribute usage: 0x%2x", attr.Type) } } // MarshalJSON implements the json Marshaller interface. func (attr *Attribute) MarshalJSON() ([]byte, error) { m := map[string]any{"type": attr.Type.String()} if attr.Value != nil { attr.Value.toJSONMap(m) } return json.Marshal(m) } // UnmarshalJSON implements the json.Unmarshaller interface. func (attr *Attribute) UnmarshalJSON(data []byte) error { aj := new(attrJSON) err := json.Unmarshal(data, aj) if err != nil { return err } switch aj.Type { case HighPriority.String(): attr.Type = HighPriority return nil case OracleResponseT.String(): attr.Type = OracleResponseT // Note: because `type` field will not be present in any attribute // value, we can unmarshal the same data. The overhead is minimal. attr.Value = new(OracleResponse) case NotValidBeforeT.String(): attr.Type = NotValidBeforeT attr.Value = new(NotValidBefore) case ConflictsT.String(): attr.Type = ConflictsT attr.Value = new(Conflicts) case NotaryAssistedT.String(): attr.Type = NotaryAssistedT attr.Value = new(NotaryAssisted) default: return errors.New("wrong Type") } return json.Unmarshal(data, attr.Value) }