package native import ( "bytes" "errors" "math/big" "sort" "github.com/nspcc-dev/neo-go/pkg/core/dao" "github.com/nspcc-dev/neo-go/pkg/core/interop" "github.com/nspcc-dev/neo-go/pkg/core/interop/contract" "github.com/nspcc-dev/neo-go/pkg/core/interop/runtime" istorage "github.com/nspcc-dev/neo-go/pkg/core/interop/storage" "github.com/nspcc-dev/neo-go/pkg/core/state" "github.com/nspcc-dev/neo-go/pkg/core/storage" "github.com/nspcc-dev/neo-go/pkg/encoding/bigint" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/smartcontract" "github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag" "github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm/stackitem" ) type nonfungible struct { interop.ContractMD tokenSymbol string tokenDecimals byte onTransferred func(nftTokenState) getTokenKey func([]byte) []byte newTokenState func() nftTokenState } type nftTokenState interface { io.Serializable ToStackItem() stackitem.Item FromStackItem(stackitem.Item) error ToMap() *stackitem.Map ID() []byte Base() *state.NFTTokenState } const ( prefixNFTTotalSupply = 11 prefixNFTAccount = 7 prefixNFTToken = 5 ) var ( nftTotalSupplyKey = []byte{prefixNFTTotalSupply} ) func newNonFungible(name string, id int32, symbol string, decimals byte) *nonfungible { n := &nonfungible{ ContractMD: *interop.NewContractMD(name, id), tokenSymbol: symbol, tokenDecimals: decimals, getTokenKey: func(tokenID []byte) []byte { return append([]byte{prefixNFTToken}, tokenID...) }, newTokenState: func() nftTokenState { return new(state.NFTTokenState) }, } n.Manifest.SupportedStandards = []string{manifest.NEP11StandardName} desc := newDescriptor("symbol", smartcontract.StringType) md := newMethodAndPrice(n.symbol, 0, callflag.NoneFlag) n.AddMethod(md, desc) desc = newDescriptor("decimals", smartcontract.IntegerType) md = newMethodAndPrice(n.decimals, 0, callflag.NoneFlag) n.AddMethod(md, desc) desc = newDescriptor("totalSupply", smartcontract.IntegerType) md = newMethodAndPrice(n.totalSupply, 1<<15, callflag.ReadStates) n.AddMethod(md, desc) desc = newDescriptor("ownerOf", smartcontract.Hash160Type, manifest.NewParameter("tokenId", smartcontract.ByteArrayType)) md = newMethodAndPrice(n.OwnerOf, 1<<15, callflag.ReadStates) n.AddMethod(md, desc) desc = newDescriptor("balanceOf", smartcontract.IntegerType, manifest.NewParameter("owner", smartcontract.Hash160Type)) md = newMethodAndPrice(n.BalanceOf, 1<<15, callflag.ReadStates) n.AddMethod(md, desc) desc = newDescriptor("properties", smartcontract.MapType, manifest.NewParameter("tokenId", smartcontract.ByteArrayType)) md = newMethodAndPrice(n.Properties, 1<<15, callflag.ReadStates) n.AddMethod(md, desc) desc = newDescriptor("tokens", smartcontract.InteropInterfaceType) md = newMethodAndPrice(n.tokens, 1<<15, callflag.ReadStates) n.AddMethod(md, desc) desc = newDescriptor("tokensOf", smartcontract.InteropInterfaceType, manifest.NewParameter("owner", smartcontract.Hash160Type)) md = newMethodAndPrice(n.tokensOf, 1<<15, callflag.ReadStates) n.AddMethod(md, desc) desc = newDescriptor("transfer", smartcontract.BoolType, manifest.NewParameter("to", smartcontract.Hash160Type), manifest.NewParameter("tokenId", smartcontract.ByteArrayType), manifest.NewParameter("data", smartcontract.AnyType)) md = newMethodAndPrice(n.transfer, 1<<17, callflag.States|callflag.AllowNotify) md.StorageFee = 50 n.AddMethod(md, desc) n.AddEvent("Transfer", manifest.NewParameter("from", smartcontract.Hash160Type), manifest.NewParameter("to", smartcontract.Hash160Type), manifest.NewParameter("amount", smartcontract.IntegerType), manifest.NewParameter("tokenId", smartcontract.ByteArrayType)) return n } // Initialize implements interop.Contract interface. func (n nonfungible) Initialize(ic *interop.Context) error { return setIntWithKey(n.ID, ic.DAO, nftTotalSupplyKey, 0) } func (n *nonfungible) symbol(_ *interop.Context, _ []stackitem.Item) stackitem.Item { return stackitem.NewByteArray([]byte(n.tokenSymbol)) } func (n *nonfungible) decimals(_ *interop.Context, _ []stackitem.Item) stackitem.Item { return stackitem.NewBigInteger(big.NewInt(int64(n.tokenDecimals))) } func (n *nonfungible) totalSupply(ic *interop.Context, _ []stackitem.Item) stackitem.Item { return stackitem.NewBigInteger(n.TotalSupply(ic.DAO)) } func (n *nonfungible) TotalSupply(d dao.DAO) *big.Int { si := d.GetStorageItem(n.ID, nftTotalSupplyKey) if si == nil { panic(errors.New("total supply is not initialized")) } return bigint.FromBytes(si) } func (n *nonfungible) setTotalSupply(d dao.DAO, ts *big.Int) { err := d.PutStorageItem(n.ID, nftTotalSupplyKey, bigint.ToBytes(ts)) if err != nil { panic(err) } } func (n *nonfungible) tokenState(d dao.DAO, tokenID []byte) (nftTokenState, []byte, error) { key := n.getTokenKey(tokenID) s := n.newTokenState() err := getSerializableFromDAO(n.ID, d, key, s) return s, key, err } func (n *nonfungible) accountState(d dao.DAO, owner util.Uint160) (*state.NFTAccountState, []byte, error) { acc := new(state.NFTAccountState) keyAcc := makeNFTAccountKey(owner) err := getSerializableFromDAO(n.ID, d, keyAcc, acc) return acc, keyAcc, err } func (n *nonfungible) putAccountState(d dao.DAO, key []byte, acc *state.NFTAccountState) { var err error if acc.Balance.Sign() == 0 { err = d.DeleteStorageItem(n.ID, key) } else { err = putSerializableToDAO(n.ID, d, key, acc) } if err != nil { panic(err) } } func (n *nonfungible) OwnerOf(ic *interop.Context, args []stackitem.Item) stackitem.Item { tokenID, err := args[0].TryBytes() if err != nil { panic(err) } s, _, err := n.tokenState(ic.DAO, tokenID) if err != nil { panic(err) } return stackitem.NewByteArray(s.Base().Owner.BytesBE()) } func (n *nonfungible) Properties(ic *interop.Context, args []stackitem.Item) stackitem.Item { tokenID, err := args[0].TryBytes() if err != nil { panic(err) } s, _, err := n.tokenState(ic.DAO, tokenID) if err != nil { panic(err) } return s.ToMap() } func (n *nonfungible) BalanceOf(ic *interop.Context, args []stackitem.Item) stackitem.Item { owner := toUint160(args[0]) s, _, err := n.accountState(ic.DAO, owner) if err != nil { if errors.Is(err, storage.ErrKeyNotFound) { return stackitem.NewBigInteger(big.NewInt(0)) } panic(err) } return stackitem.NewBigInteger(&s.Balance) } func (n *nonfungible) tokens(ic *interop.Context, args []stackitem.Item) stackitem.Item { prefix := []byte{prefixNFTToken} siMap, err := ic.DAO.GetStorageItemsWithPrefix(n.ID, prefix) if err != nil { panic(err) } filteredMap := stackitem.NewMap() for k, v := range siMap { filteredMap.Add(stackitem.NewByteArray(append(prefix, []byte(k)...)), stackitem.NewByteArray(v)) } sort.Slice(filteredMap.Value().([]stackitem.MapElement), func(i, j int) bool { return bytes.Compare(filteredMap.Value().([]stackitem.MapElement)[i].Key.Value().([]byte), filteredMap.Value().([]stackitem.MapElement)[j].Key.Value().([]byte)) == -1 }) iter := istorage.NewIterator(filteredMap, 1, istorage.FindValuesOnly|istorage.FindDeserialize|istorage.FindPick1) return stackitem.NewInterop(iter) } func (n *nonfungible) tokensOf(ic *interop.Context, args []stackitem.Item) stackitem.Item { owner := toUint160(args[0]) s, _, err := n.accountState(ic.DAO, owner) if err != nil { panic(err) } arr := make([]stackitem.Item, len(s.Tokens)) for i := range arr { arr[i] = stackitem.NewByteArray(s.Tokens[i]) } iter := newArrayIterator(arr) return stackitem.NewInterop(iter) } func (n *nonfungible) mint(ic *interop.Context, s nftTokenState) { key := n.getTokenKey(s.ID()) if ic.DAO.GetStorageItem(n.ID, key) != nil { panic("token is already minted") } if err := putSerializableToDAO(n.ID, ic.DAO, key, s); err != nil { panic(err) } owner := s.Base().Owner acc, keyAcc, err := n.accountState(ic.DAO, owner) if err != nil && !errors.Is(err, storage.ErrKeyNotFound) { panic(err) } acc.Add(s.ID()) n.putAccountState(ic.DAO, keyAcc, acc) ts := n.TotalSupply(ic.DAO) ts.Add(ts, intOne) n.setTotalSupply(ic.DAO, ts) n.postTransfer(ic, nil, &owner, s.ID(), stackitem.Null{}) } func (n *nonfungible) postTransfer(ic *interop.Context, from, to *util.Uint160, tokenID []byte, data stackitem.Item) { ne := state.NotificationEvent{ ScriptHash: n.Hash, Name: "Transfer", Item: stackitem.NewArray([]stackitem.Item{ addrToStackItem(from), addrToStackItem(to), stackitem.NewBigInteger(intOne), stackitem.NewByteArray(tokenID), }), } ic.Notifications = append(ic.Notifications, ne) if to == nil { return } cs, err := ic.GetContract(*to) if err != nil { return } fromArg := stackitem.Item(stackitem.Null{}) if from != nil { fromArg = stackitem.NewByteArray((*from).BytesBE()) } args := []stackitem.Item{ fromArg, stackitem.NewBigInteger(intOne), stackitem.NewByteArray(tokenID), data, } if err := contract.CallFromNative(ic, n.Hash, cs, manifest.MethodOnNEP11Payment, args, false); err != nil { panic(err) } } func (n *nonfungible) burn(ic *interop.Context, tokenID []byte) { key := n.getTokenKey(tokenID) n.burnByKey(ic, key) } func (n *nonfungible) burnByKey(ic *interop.Context, key []byte) { token := n.newTokenState() err := getSerializableFromDAO(n.ID, ic.DAO, key, token) if err != nil { panic(err) } if err := ic.DAO.DeleteStorageItem(n.ID, key); err != nil { panic(err) } owner := token.Base().Owner acc, keyAcc, err := n.accountState(ic.DAO, owner) if err != nil { panic(err) } id := token.ID() acc.Remove(id) n.putAccountState(ic.DAO, keyAcc, acc) ts := n.TotalSupply(ic.DAO) ts.Sub(ts, intOne) n.setTotalSupply(ic.DAO, ts) n.postTransfer(ic, &owner, nil, id, stackitem.Null{}) } func (n *nonfungible) transfer(ic *interop.Context, args []stackitem.Item) stackitem.Item { to := toUint160(args[0]) tokenID, err := args[1].TryBytes() if err != nil { panic(err) } token, tokenKey, err := n.tokenState(ic.DAO, tokenID) if err != nil { panic(err) } from := token.Base().Owner ok, err := runtime.CheckHashedWitness(ic, from) if err != nil || !ok { return stackitem.NewBool(false) } if from != to { acc, key, err := n.accountState(ic.DAO, from) if err != nil { panic(err) } acc.Remove(tokenID) n.putAccountState(ic.DAO, key, acc) token.Base().Owner = to n.onTransferred(token) err = putSerializableToDAO(n.ID, ic.DAO, tokenKey, token) if err != nil { panic(err) } acc, key, err = n.accountState(ic.DAO, to) if err != nil && !errors.Is(err, storage.ErrKeyNotFound) { panic(err) } acc.Add(tokenID) n.putAccountState(ic.DAO, key, acc) } n.postTransfer(ic, &from, &to, tokenID, args[2]) return stackitem.NewBool(true) } func makeNFTAccountKey(owner util.Uint160) []byte { return append([]byte{prefixNFTAccount}, owner.BytesBE()...) } type arrayWrapper struct { index int value []stackitem.Item } func newArrayIterator(arr []stackitem.Item) *arrayWrapper { return &arrayWrapper{ index: -1, value: arr, } } func (a *arrayWrapper) Next() bool { if next := a.index + 1; next < len(a.value) { a.index = next return true } return false } func (a *arrayWrapper) Value() stackitem.Item { return a.value[a.index] }