package runtime import ( "encoding/binary" "errors" "math/big" "github.com/nspcc-dev/neo-go/pkg/config" "github.com/nspcc-dev/neo-go/pkg/core/interop" "github.com/nspcc-dev/neo-go/pkg/core/state" "github.com/nspcc-dev/neo-go/pkg/encoding/address" "github.com/nspcc-dev/neo-go/pkg/encoding/bigint" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm" "github.com/nspcc-dev/neo-go/pkg/vm/stackitem" "github.com/twmb/murmur3" ) // GasLeft returns the remaining amount of GAS. func GasLeft(ic *interop.Context) error { if ic.VM.GasLimit == -1 { ic.VM.Estack().PushItem(stackitem.NewBigInteger(big.NewInt(ic.VM.GasLimit))) } else { ic.VM.Estack().PushItem(stackitem.NewBigInteger(big.NewInt(ic.VM.GasLimit - ic.VM.GasConsumed()))) } return nil } // GetNotifications returns notifications emitted in the current execution context. func GetNotifications(ic *interop.Context) error { item := ic.VM.Estack().Pop().Item() notifications := ic.Notifications if _, ok := item.(stackitem.Null); !ok { b, err := item.TryBytes() if err != nil { return err } u, err := util.Uint160DecodeBytesBE(b) if err != nil { return err } notifications = []state.NotificationEvent{} for i := range ic.Notifications { if ic.Notifications[i].ScriptHash.Equals(u) { notifications = append(notifications, ic.Notifications[i]) } } } if len(notifications) > vm.MaxStackSize { return errors.New("too many notifications") } arr := stackitem.NewArray(make([]stackitem.Item, 0, len(notifications))) for i := range notifications { ev := stackitem.NewArray([]stackitem.Item{ stackitem.NewByteArray(notifications[i].ScriptHash.BytesBE()), stackitem.Make(notifications[i].Name), notifications[i].Item, }) arr.Append(ev) } ic.VM.Estack().PushItem(arr) return nil } // GetInvocationCounter returns how many times the current contract has been invoked during the current tx execution. func GetInvocationCounter(ic *interop.Context) error { currentScriptHash := ic.VM.GetCurrentScriptHash() count, ok := ic.Invocations[currentScriptHash] if !ok { count = 1 ic.Invocations[currentScriptHash] = count } ic.VM.Estack().PushItem(stackitem.NewBigInteger(big.NewInt(int64(count)))) return nil } // GetAddressVersion returns the address version of the current protocol. func GetAddressVersion(ic *interop.Context) error { ic.VM.Estack().PushItem(stackitem.NewBigInteger(big.NewInt(int64(address.NEO3Prefix)))) return nil } // GetNetwork returns chain network number. func GetNetwork(ic *interop.Context) error { m := ic.Chain.GetConfig().Magic ic.VM.Estack().PushItem(stackitem.NewBigInteger(big.NewInt(int64(m)))) return nil } // GetRandom returns pseudo-random number which depends on block nonce and transaction hash. func GetRandom(ic *interop.Context) error { var ( price int64 seed = ic.Network ) isHF := ic.IsHardforkEnabled(config.HFAspidochelone) if isHF { price = 1 << 13 seed += ic.GetRandomCounter ic.GetRandomCounter++ } else { price = 1 << 4 } res := murmur128(ic.NonceData[:], seed) if !isHF { copy(ic.NonceData[:], res) } if !ic.VM.AddGas(ic.BaseExecFee() * price) { return errors.New("gas limit exceeded") } ic.VM.Estack().PushItem(stackitem.NewBigInteger(bigint.FromBytesUnsigned(res))) return nil } func murmur128(data []byte, seed uint32) []byte { h1, h2 := murmur3.SeedSum128(uint64(seed), uint64(seed), data) result := make([]byte, 16) binary.LittleEndian.PutUint64(result, h1) binary.LittleEndian.PutUint64(result[8:], h2) return result }