package state import ( "bytes" "math/big" "github.com/nspcc-dev/neo-go/pkg/encoding/bigint" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/util" ) // NEP17TransferBatchSize is the maximum number of entries for NEP17TransferLog. const NEP17TransferBatchSize = 128 // NEP17TransferLog is a log of NEP17 token transfers for the specific command. type NEP17TransferLog struct { Raw []byte } // NEP17Transfer represents a single NEP17 Transfer event. type NEP17Transfer struct { // Asset is a NEP17 contract ID. Asset int32 // Address is the address of the sender. From util.Uint160 // To is the address of the receiver. To util.Uint160 // Amount is the amount of tokens transferred. // It is negative when tokens are sent and positive if they are received. Amount big.Int // Block is a number of block when the event occurred. Block uint32 // Timestamp is the timestamp of the block where transfer occurred. Timestamp uint64 // Tx is a hash the transaction. Tx util.Uint256 } // NEP17TransferInfo stores map of the NEP17 contract IDs to the balance's last updated // block trackers along with information about NEP17 transfer batch. type NEP17TransferInfo struct { LastUpdated map[int32]uint32 // NextTransferBatch stores an index of the next transfer batch. NextTransferBatch uint32 // NewBatch is true if batch with the `NextTransferBatch` index should be created. NewBatch bool } // NewNEP17TransferInfo returns new NEP17TransferInfo. func NewNEP17TransferInfo() *NEP17TransferInfo { return &NEP17TransferInfo{ LastUpdated: make(map[int32]uint32), } } // DecodeBinary implements io.Serializable interface. func (bs *NEP17TransferInfo) DecodeBinary(r *io.BinReader) { bs.NextTransferBatch = r.ReadU32LE() bs.NewBatch = r.ReadBool() lenBalances := r.ReadVarUint() m := make(map[int32]uint32, lenBalances) for i := 0; i < int(lenBalances); i++ { key := int32(r.ReadU32LE()) m[key] = r.ReadU32LE() } bs.LastUpdated = m } // EncodeBinary implements io.Serializable interface. func (bs *NEP17TransferInfo) EncodeBinary(w *io.BinWriter) { w.WriteU32LE(bs.NextTransferBatch) w.WriteBool(bs.NewBatch) w.WriteVarUint(uint64(len(bs.LastUpdated))) for k, v := range bs.LastUpdated { w.WriteU32LE(uint32(k)) w.WriteU32LE(v) } } // Append appends single transfer to a log. func (lg *NEP17TransferLog) Append(tr *NEP17Transfer) error { // The first entry, set up counter. if len(lg.Raw) == 0 { lg.Raw = append(lg.Raw, 0) } b := bytes.NewBuffer(lg.Raw) w := io.NewBinWriterFromIO(b) tr.EncodeBinary(w) if w.Err != nil { return w.Err } lg.Raw = b.Bytes() lg.Raw[0]++ return nil } // ForEach iterates over transfer log returning on first error. func (lg *NEP17TransferLog) ForEach(f func(*NEP17Transfer) (bool, error)) (bool, error) { if lg == nil || len(lg.Raw) == 0 { return true, nil } transfers := make([]NEP17Transfer, lg.Size()) r := io.NewBinReaderFromBuf(lg.Raw[1:]) for i := 0; i < lg.Size(); i++ { transfers[i].DecodeBinary(r) } if r.Err != nil { return false, r.Err } for i := len(transfers) - 1; i >= 0; i-- { cont, err := f(&transfers[i]) if err != nil { return false, err } if !cont { return false, nil } } return true, nil } // Size returns an amount of transfer written in log. func (lg *NEP17TransferLog) Size() int { if len(lg.Raw) == 0 { return 0 } return int(lg.Raw[0]) } // EncodeBinary implements io.Serializable interface. func (t *NEP17Transfer) EncodeBinary(w *io.BinWriter) { w.WriteU32LE(uint32(t.Asset)) w.WriteBytes(t.Tx[:]) w.WriteBytes(t.From[:]) w.WriteBytes(t.To[:]) w.WriteU32LE(t.Block) w.WriteU64LE(t.Timestamp) amount := bigint.ToBytes(&t.Amount) w.WriteVarBytes(amount) } // DecodeBinary implements io.Serializable interface. func (t *NEP17Transfer) DecodeBinary(r *io.BinReader) { t.Asset = int32(r.ReadU32LE()) r.ReadBytes(t.Tx[:]) r.ReadBytes(t.From[:]) r.ReadBytes(t.To[:]) t.Block = r.ReadU32LE() t.Timestamp = r.ReadU64LE() amount := r.ReadVarBytes(bigint.MaxBytesLen) t.Amount = *bigint.FromBytes(amount) }