core: implement new System.Blockchain.GetTransaction interop

closes #1023

Now we put on stack stackitem.Array instead of Interop, so we don't
need old transaction-related interops anymore. Removed the following
interops:
	System.Transaction.GetHash
	Neo.Transaction.GetAttributes
	Neo.Transaction.GetHash
	Neo.Transaction.GetWitnesses
	Neo.Attribute.GetData
	Neo.Attribute.GetUsage

Also removed the following duplicated NEO interop:
	Neo.Blockchain.GetTransaction

pkg/compiler/codegen.go

@@ -1053,6 +1053,10 @@ func (c *codegen) convertSyscall(expr *ast.CallExpr, api, name string) {
 		emit.Opcode(c.prog.BinWriter, opcode.PACK)
 	}
 	emit.Syscall(c.prog.BinWriter, api)
+	switch name {
+	case "GetTransaction":
+		c.emitConvert(stackitem.StructT)
+	}
 
 	// This NOP instruction is basically not needed, but if we do, we have a
 	// one to one matching avm file with neo-python which is very nice for debugging.

pkg/compiler/syscall.go

@@ -7,10 +7,6 @@ var syscalls = map[string]map[string]string{
 		"GetVotes":      "Neo.Account.GetVotes",
 		"IsStandard":    "Neo.Account.IsStandard",
 	},
-	"attribute": {
-		"GetUsage": "Neo.Attribute.GetUsage",
-		"GetData":  "Neo.Attribute.GetData",
-	},
 	"crypto": {
 		"ECDsaVerify": "Neo.Crypto.ECDsaVerify",
 	},
@@ -44,7 +40,7 @@ var syscalls = map[string]map[string]string{
 		"GetContract":          "Neo.Blockchain.GetContract",
 		"GetHeader":            "Neo.Blockchain.GetHeader",
 		"GetHeight":            "Neo.Blockchain.GetHeight",
-		"GetTransaction":       "Neo.Blockchain.GetTransaction",
+		"GetTransaction":       "System.Blockchain.GetTransaction",
 		"GetTransactionHeight": "Neo.Blockchain.GetTransactionHeight",
 		"GetValidators":        "Neo.Blockchain.GetValidators",
 	},
@@ -63,11 +59,6 @@ var syscalls = map[string]map[string]string{
 		"GetTransactions":     "Neo.Block.GetTransactions",
 		"GetTransaction":      "Neo.Block.GetTransaction",
 	},
-	"transaction": {
-		"GetAttributes": "Neo.Transaction.GetAttributes",
-		"GetHash":       "Neo.Transaction.GetHash",
-		"GetWitnesses":  "Neo.Transaction.GetWitnesses",
-	},
 	"contract": {
 		"GetScript":         "Neo.Contract.GetScript",
 		"IsPayable":         "Neo.Contract.IsPayable",

pkg/core/interop_neo.go

@@ -57,42 +57,6 @@ func headerGetNextConsensus(ic *interop.Context, v *vm.VM) error {
 	return nil
 }
 
-// txGetAttributes returns current transaction attributes.
-func txGetAttributes(ic *interop.Context, v *vm.VM) error {
-	txInterface := v.Estack().Pop().Value()
-	tx, ok := txInterface.(*transaction.Transaction)
-	if !ok {
-		return errors.New("value is not a transaction")
-	}
-	if len(tx.Attributes) > vm.MaxArraySize {
-		return errors.New("too many attributes")
-	}
-	attrs := make([]stackitem.Item, 0, len(tx.Attributes))
-	for i := range tx.Attributes {
-		attrs = append(attrs, stackitem.NewInterop(&tx.Attributes[i]))
-	}
-	v.Estack().PushVal(attrs)
-	return nil
-}
-
-// txGetWitnesses returns current transaction witnesses.
-func txGetWitnesses(ic *interop.Context, v *vm.VM) error {
-	txInterface := v.Estack().Pop().Value()
-	tx, ok := txInterface.(*transaction.Transaction)
-	if !ok {
-		return errors.New("value is not a transaction")
-	}
-	if len(tx.Scripts) > vm.MaxArraySize {
-		return errors.New("too many outputs")
-	}
-	scripts := make([]stackitem.Item, 0, len(tx.Scripts))
-	for i := range tx.Scripts {
-		scripts = append(scripts, stackitem.NewInterop(&tx.Scripts[i]))
-	}
-	v.Estack().PushVal(scripts)
-	return nil
-}
-
 // witnessGetVerificationScript returns current witness' script.
 func witnessGetVerificationScript(ic *interop.Context, v *vm.VM) error {
 	witInterface := v.Estack().Pop().Value()
@@ -107,28 +71,6 @@ func witnessGetVerificationScript(ic *interop.Context, v *vm.VM) error {
 	return nil
 }
 
-// attrGetData returns tx attribute data.
-func attrGetData(ic *interop.Context, v *vm.VM) error {
-	attrInterface := v.Estack().Pop().Value()
-	attr, ok := attrInterface.(*transaction.Attribute)
-	if !ok {
-		return fmt.Errorf("%T is not an attribute", attr)
-	}
-	v.Estack().PushVal(attr.Data)
-	return nil
-}
-
-// attrGetData returns tx attribute usage field.
-func attrGetUsage(ic *interop.Context, v *vm.VM) error {
-	attrInterface := v.Estack().Pop().Value()
-	attr, ok := attrInterface.(*transaction.Attribute)
-	if !ok {
-		return fmt.Errorf("%T is not an attribute", attr)
-	}
-	v.Estack().PushVal(int(attr.Usage))
-	return nil
-}
-
 // bcGetAccount returns or creates an account.
 func bcGetAccount(ic *interop.Context, v *vm.VM) error {
 	accbytes := v.Estack().Pop().Bytes()

pkg/core/interop_neo_test.go

@@ -178,16 +178,6 @@ func TestHeaderGetNextConsensus(t *testing.T) {
 	require.Equal(t, block.NextConsensus.BytesBE(), value)
 }
 
-func TestTxGetAttributes(t *testing.T) {
-	v, tx, context, chain := createVMAndPushTX(t)
-	defer chain.Close()
-
-	err := txGetAttributes(context, v)
-	require.NoError(t, err)
-	value := v.Estack().Pop().Value().([]stackitem.Item)
-	require.Equal(t, tx.Attributes[0].Usage, value[0].Value().(*transaction.Attribute).Usage)
-}
-
 func TestWitnessGetVerificationScript(t *testing.T) {
 	v := vm.New()
 	script := []byte{byte(opcode.PUSHM1), byte(opcode.RET)}
@@ -280,28 +270,6 @@ func TestECDSAVerify(t *testing.T) {
 	})
 }
 
-func TestAttrGetData(t *testing.T) {
-	v, tx, context, chain := createVMAndTX(t)
-	defer chain.Close()
-	v.Estack().PushVal(stackitem.NewInterop(&tx.Attributes[0]))
-
-	err := attrGetData(context, v)
-	require.NoError(t, err)
-	data := v.Estack().Pop().Value()
-	require.Equal(t, tx.Attributes[0].Data, data)
-}
-
-func TestAttrGetUsage(t *testing.T) {
-	v, tx, context, chain := createVMAndTX(t)
-	defer chain.Close()
-	v.Estack().PushVal(stackitem.NewInterop(&tx.Attributes[0]))
-
-	err := attrGetUsage(context, v)
-	require.NoError(t, err)
-	usage := v.Estack().Pop().Value()
-	require.Equal(t, big.NewInt(int64(tx.Attributes[0].Usage)), usage)
-}
-
 func TestAccountGetScriptHash(t *testing.T) {
 	v, accState, context, chain := createVMAndAccState(t)
 	defer chain.Close()

pkg/core/interop_system.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"math/big"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
@@ -22,6 +23,9 @@ import (
 const (
 	// MaxStorageKeyLen is the maximum length of a key for storage items.
 	MaxStorageKeyLen = 1024
+	// MaxTraceableBlocks is the maximum number of blocks before current chain
+	// height we're able to give information about.
+	MaxTraceableBlocks = transaction.MaxValidUntilBlockIncrement
 )
 
 // StorageContext contains storing script hash and read/write flag, it's used as
@@ -112,13 +116,35 @@ func getTransactionAndHeight(cd *dao.Cached, v *vm.VM) (*transaction.Transaction
 	return cd.GetTransaction(hash)
 }
 
+// isTraceableBlock defines whether we're able to give information about
+// the block with index specified.
+func isTraceableBlock(ic *interop.Context, index uint32) bool {
+	height := ic.Chain.BlockHeight()
+	return index <= height && index+MaxTraceableBlocks > height
+}
+
+// transactionToStackItem converts transaction.Transaction to stackitem.Item
+func transactionToStackItem(t *transaction.Transaction) stackitem.Item {
+	return stackitem.NewArray([]stackitem.Item{
+		stackitem.NewByteArray(t.Hash().BytesBE()),
+		stackitem.NewBigInteger(big.NewInt(int64(t.Version))),
+		stackitem.NewBigInteger(big.NewInt(int64(t.Nonce))),
+		stackitem.NewByteArray(t.Sender.BytesBE()),
+		stackitem.NewBigInteger(big.NewInt(int64(t.SystemFee))),
+		stackitem.NewBigInteger(big.NewInt(int64(t.NetworkFee))),
+		stackitem.NewBigInteger(big.NewInt(int64(t.ValidUntilBlock))),
+		stackitem.NewByteArray(t.Script),
+	})
+}
+
 // bcGetTransaction returns transaction.
 func bcGetTransaction(ic *interop.Context, v *vm.VM) error {
-	tx, _, err := getTransactionAndHeight(ic.DAO, v)
+	tx, h, err := getTransactionAndHeight(ic.DAO, v)
-	if err != nil {
+	if err != nil || !isTraceableBlock(ic, h) {
-		return err
+		v.Estack().PushVal(stackitem.Null{})
+		return nil
 	}
-	v.Estack().PushVal(stackitem.NewInterop(tx))
+	v.Estack().PushVal(transactionToStackItem(tx))
 	return nil
 }
 
@@ -234,17 +260,6 @@ func blockGetTransaction(ic *interop.Context, v *vm.VM) error {
 	return nil
 }
 
-// txGetHash returns transaction's hash.
-func txGetHash(ic *interop.Context, v *vm.VM) error {
-	txInterface := v.Estack().Pop().Value()
-	tx, ok := txInterface.(*transaction.Transaction)
-	if !ok {
-		return errors.New("value is not a transaction")
-	}
-	v.Estack().PushVal(tx.Hash().BytesBE())
-	return nil
-}
-
 // engineGetScriptContainer returns transaction that contains the script being
 // run.
 func engineGetScriptContainer(ic *interop.Context, v *vm.VM) error {

pkg/core/interop_system_test.go

@@ -0,0 +1,54 @@
+package core
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBCGetTransaction(t *testing.T) {
+	v, tx, context, chain := createVMAndTX(t)
+	defer chain.Close()
+
+	t.Run("success", func(t *testing.T) {
+		require.NoError(t, context.DAO.StoreAsTransaction(tx, 0))
+		v.Estack().PushVal(tx.Hash().BytesBE())
+		err := bcGetTransaction(context, v)
+		require.NoError(t, err)
+
+		value := v.Estack().Pop().Value()
+		actual, ok := value.([]stackitem.Item)
+		require.True(t, ok)
+		require.Equal(t, 8, len(actual))
+		require.Equal(t, tx.Hash().BytesBE(), actual[0].Value().([]byte))
+		require.Equal(t, int64(tx.Version), actual[1].Value().(*big.Int).Int64())
+		require.Equal(t, int64(tx.Nonce), actual[2].Value().(*big.Int).Int64())
+		require.Equal(t, tx.Sender.BytesBE(), actual[3].Value().([]byte))
+		require.Equal(t, int64(tx.SystemFee), actual[4].Value().(*big.Int).Int64())
+		require.Equal(t, int64(tx.NetworkFee), actual[5].Value().(*big.Int).Int64())
+		require.Equal(t, int64(tx.ValidUntilBlock), actual[6].Value().(*big.Int).Int64())
+		require.Equal(t, tx.Script, actual[7].Value().([]byte))
+	})
+
+	t.Run("isn't traceable", func(t *testing.T) {
+		require.NoError(t, context.DAO.StoreAsTransaction(tx, 1))
+		v.Estack().PushVal(tx.Hash().BytesBE())
+		err := bcGetTransaction(context, v)
+		require.NoError(t, err)
+
+		_, ok := v.Estack().Pop().Item().(stackitem.Null)
+		require.True(t, ok)
+	})
+
+	t.Run("bad hash", func(t *testing.T) {
+		require.NoError(t, context.DAO.StoreAsTransaction(tx, 1))
+		v.Estack().PushVal(tx.Hash().BytesLE())
+		err := bcGetTransaction(context, v)
+		require.NoError(t, err)
+
+		_, ok := v.Estack().Pop().Item().(stackitem.Null)
+		require.True(t, ok)
+	})
+}

pkg/core/interops.go

@@ -69,7 +69,7 @@ var systemInterops = []interop.Function{
 	{Name: "System.Blockchain.GetContract", Func: bcGetContract, Price: 100},
 	{Name: "System.Blockchain.GetHeader", Func: bcGetHeader, Price: 100},
 	{Name: "System.Blockchain.GetHeight", Func: bcGetHeight, Price: 1},
-	{Name: "System.Blockchain.GetTransaction", Func: bcGetTransaction, Price: 200},
+	{Name: "System.Blockchain.GetTransaction", Func: bcGetTransaction, Price: 100},
 	{Name: "System.Blockchain.GetTransactionHeight", Func: bcGetTransactionHeight, Price: 100},
 	{Name: "System.Contract.Call", Func: contractCall, Price: 1},
 	{Name: "System.Contract.CallEx", Func: contractCallEx, Price: 1},
@@ -98,15 +98,12 @@ var systemInterops = []interop.Function{
 	{Name: "System.Storage.Put", Func: storagePut, Price: 0}, // These don't have static price in C# code.
 	{Name: "System.Storage.PutEx", Func: storagePutEx, Price: 0},
 	{Name: "System.StorageContext.AsReadOnly", Func: storageContextAsReadOnly, Price: 1},
-	{Name: "System.Transaction.GetHash", Func: txGetHash, Price: 1},
 }
 
 var neoInterops = []interop.Function{
 	{Name: "Neo.Account.GetBalance", Func: accountGetBalance, Price: 1},
 	{Name: "Neo.Account.GetScriptHash", Func: accountGetScriptHash, Price: 1},
 	{Name: "Neo.Account.IsStandard", Func: accountIsStandard, Price: 100},
-	{Name: "Neo.Attribute.GetData", Func: attrGetData, Price: 1},
-	{Name: "Neo.Attribute.GetUsage", Func: attrGetUsage, Price: 1},
 	{Name: "Neo.Block.GetTransaction", Func: blockGetTransaction, Price: 1},
 	{Name: "Neo.Block.GetTransactionCount", Func: blockGetTransactionCount, Price: 1},
 	{Name: "Neo.Block.GetTransactions", Func: blockGetTransactions, Price: 1},
@@ -115,7 +112,6 @@ var neoInterops = []interop.Function{
 	{Name: "Neo.Blockchain.GetContract", Func: bcGetContract, Price: 100},
 	{Name: "Neo.Blockchain.GetHeader", Func: bcGetHeader, Price: 100},
 	{Name: "Neo.Blockchain.GetHeight", Func: bcGetHeight, Price: 1},
-	{Name: "Neo.Blockchain.GetTransaction", Func: bcGetTransaction, Price: 100},
 	{Name: "Neo.Blockchain.GetTransactionHeight", Func: bcGetTransactionHeight, Price: 100},
 	{Name: "Neo.Contract.Create", Func: contractCreate, Price: 0},
 	{Name: "Neo.Contract.Destroy", Func: contractDestroy, Price: 1},
@@ -157,9 +153,6 @@ var neoInterops = []interop.Function{
 	{Name: "Neo.Storage.GetReadOnlyContext", Func: storageGetReadOnlyContext, Price: 1},
 	{Name: "Neo.Storage.Put", Func: storagePut, Price: 0},
 	{Name: "Neo.StorageContext.AsReadOnly", Func: storageContextAsReadOnly, Price: 1},
-	{Name: "Neo.Transaction.GetAttributes", Func: txGetAttributes, Price: 1},
-	{Name: "Neo.Transaction.GetHash", Func: txGetHash, Price: 1},
-	{Name: "Neo.Transaction.GetWitnesses", Func: txGetWitnesses, Price: 200},
 	{Name: "Neo.Witness.GetVerificationScript", Func: witnessGetVerificationScript, Price: 100},
 
 	// Aliases.

pkg/core/interops_test.go

@@ -34,8 +34,6 @@ func TestUnexpectedNonInterops(t *testing.T) {
 	funcs := []func(*interop.Context, *vm.VM) error{
 		accountGetBalance,
 		accountGetScriptHash,
-		attrGetData,
-		attrGetUsage,
 		blockGetTransaction,
 		blockGetTransactionCount,
 		blockGetTransactions,
@@ -55,9 +53,6 @@ func TestUnexpectedNonInterops(t *testing.T) {
 		storageGet,
 		storagePut,
 		storagePutEx,
-		txGetAttributes,
-		txGetHash,
-		txGetWitnesses,
 		witnessGetVerificationScript,
 	}
 	for _, f := range funcs {

pkg/interop/attribute/attribute.go

@@ -1,65 +0,0 @@
-/*
-Package attribute provides getters for transaction attributes.
-*/
-package attribute
-
-// Attribute represents transaction attribute in Neo, it's an opaque data
-// structure that you can get data from only using functions from this package.
-// It's similar in function to the TransactionAttribute class in the Neo .net
-// framework. To use it you need to get is first using transaction.GetAttributes.
-type Attribute struct{}
-
-// GetUsage returns the Usage field of the given attribute. It is an enumeration
-// with the following possible values:
-//      ContractHash   = 0x00
-//      ECDH02         = 0x02
-//      ECDH03         = 0x03
-//      Script         = 0x20
-//      Vote           = 0x30
-//      CertURL        = 0x80
-//      DescriptionURL = 0x81
-//      Description    = 0x90
-//
-//      Hash1  = 0xa1
-//      Hash2  = 0xa2
-//      Hash3  = 0xa3
-//      Hash4  = 0xa4
-//      Hash5  = 0xa5
-//      Hash6  = 0xa6
-//      Hash7  = 0xa7
-//      Hash8  = 0xa8
-//      Hash9  = 0xa9
-//      Hash10 = 0xaa
-//      Hash11 = 0xab
-//      Hash12 = 0xac
-//      Hash13 = 0xad
-//      Hash14 = 0xae
-//      Hash15 = 0xaf
-//
-//      Remark   = 0xf0
-//      Remark1  = 0xf1
-//      Remark2  = 0xf2
-//      Remark3  = 0xf3
-//      Remark4  = 0xf4
-//      Remark5  = 0xf5
-//      Remark6  = 0xf6
-//      Remark7  = 0xf7
-//      Remark8  = 0xf8
-//      Remark9  = 0xf9
-//      Remark10 = 0xfa
-//      Remark11 = 0xfb
-//      Remark12 = 0xfc
-//      Remark13 = 0xfd
-//      Remark14 = 0xfe
-//      Remark15 = 0xff
-// This function uses `Neo.Attribute.GetUsage` syscall internally.
-func GetUsage(attr Attribute) byte {
-	return 0x00
-}
-
-// GetData returns the data of the given attribute, exact interpretation of this
-// data depends on attribute's Usage type. It uses `Neo.Attribute.GetData`
-// syscall internally.
-func GetData(attr Attribute) []byte {
-	return nil
-}

pkg/interop/block/block.go

@@ -3,7 +3,7 @@ Package block provides getters for Neo Block structure.
 */
 package block
 
-import "github.com/nspcc-dev/neo-go/pkg/interop/transaction"
+import "github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 
 // Block represents a NEO block, it's an opaque data structure that you can get
 // data from only using functions from this package. It's similar in function to
@@ -19,12 +19,12 @@ func GetTransactionCount(b Block) int {
 
 // GetTransactions returns a slice of transactions recorded in the given block.
 // It uses `Neo.Block.GetTransactions` syscall internally.
-func GetTransactions(b Block) []transaction.Transaction {
+func GetTransactions(b Block) []blockchain.Transaction {
-	return []transaction.Transaction{}
+	return []blockchain.Transaction{}
 }
 
 // GetTransaction returns transaction from the given block by its index. It
 // uses `Neo.Block.GetTransaction` syscall internally.
-func GetTransaction(b Block, index int) transaction.Transaction {
+func GetTransaction(b Block, index int) blockchain.Transaction {
-	return transaction.Transaction{}
+	return blockchain.Transaction{}
 }

pkg/interop/blockchain/blockchain.go

@@ -8,9 +8,32 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/interop/block"
 	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
 	"github.com/nspcc-dev/neo-go/pkg/interop/header"
-	"github.com/nspcc-dev/neo-go/pkg/interop/transaction"
 )
 
+// Transaction represents a NEO transaction. It's similar to Transaction class
+// in Neo .net framework.
+type Transaction struct {
+	// Hash represents the hash (256 bit BE value in a 32 byte slice) of the
+	// given transaction (which also is its ID).
+	Hash []byte
+	// Version represents the transaction version.
+	Version int
+	// Nonce is a random number to avoid hash collision.
+	Nonce int
+	// Sender represents the sender (160 bit BE value in a 20 byte slice) of the
+	// given Transaction.
+	Sender []byte
+	// SysFee represents fee to be burned.
+	SysFee int
+	// NetFee represents fee to be distributed to consensus nodes.
+	NetFee int
+	// ValidUntilBlock is the maximum blockchain height exceeding which
+	// transaction should fail verification.
+	ValidUntilBlock int
+	// Script represents code to run in NeoVM for this transaction.
+	Script []byte
+}
+
 // GetHeight returns current block height (index of the last accepted block).
 // Note that when transaction is being run as a part of new block this block is
 // considered as not yet accepted (persisted) and thus you'll get an index of
@@ -35,12 +58,11 @@ func GetBlock(heightOrHash interface{}) block.Block {
 	return block.Block{}
 }
 
-// GetTransaction returns transaction found by the given (256 bit in BE format
+// GetTransaction returns transaction found by the given hash (256 bit in BE
-// represented as a slice of 32 bytes). Refer to the `transaction` package for
+// format represented as a slice of 32 bytes). This function uses
-// possible uses of returned structure. This function uses
+// `System.Blockchain.GetTransaction` syscall.
-// `Neo.Blockchain.GetTransaction` syscall.
+func GetTransaction(hash []byte) Transaction {
-func GetTransaction(hash []byte) transaction.Transaction {
+	return Transaction{}
-	return transaction.Transaction{}
 }
 
 // GetTransactionHeight returns transaction's height (index of the block that

pkg/interop/engine/engine.go

@@ -5,15 +5,14 @@ framework.
 */
 package engine
 
-import "github.com/nspcc-dev/neo-go/pkg/interop/transaction"
+import "github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 
 // GetScriptContainer returns the transaction that initially triggered current
 // execution context. It never changes in a single execution, no matter how deep
-// this execution goes. See `transaction` package for details on how to use the
+// this execution goes. This function uses
-// returned value. This function uses `System.ExecutionEngine.GetScriptContainer`
+// `System.ExecutionEngine.GetScriptContainer` syscall.
-// syscall.
+func GetScriptContainer() blockchain.Transaction {
-func GetScriptContainer() transaction.Transaction {
+	return blockchain.Transaction{}
-	return transaction.Transaction{}
 }
 
 // GetExecutingScriptHash returns script hash (160 bit in BE form represented

pkg/interop/transaction/transaction.go

@@ -1,34 +0,0 @@
-/*
-Package transaction provides functions to work with transactions.
-*/
-package transaction
-
-import (
-	"github.com/nspcc-dev/neo-go/pkg/interop/attribute"
-	"github.com/nspcc-dev/neo-go/pkg/interop/witness"
-)
-
-// Transaction represents a NEO transaction, it's an opaque data structure
-// that can be used with functions from this package. It's similar to
-// Transaction class in Neo .net framework.
-type Transaction struct{}
-
-// GetHash returns the hash (256 bit BE value in a 32 byte slice) of the given
-// transaction (which also is its ID). Is uses `Neo.Transaction.GetHash` syscall.
-func GetHash(t Transaction) []byte {
-	return nil
-}
-
-// GetAttributes returns a slice of attributes for agiven transaction. Refer to
-// attribute package on how to use them. This function uses
-// `Neo.Transaction.GetAttributes` syscall.
-func GetAttributes(t Transaction) []attribute.Attribute {
-	return []attribute.Attribute{}
-}
-
-// GetWitnesses returns a slice of witnesses of a given Transaction. Refer to
-// witness package on how to use them. This function uses
-// `Neo.Transaction.GetWitnesses` syscall.
-func GetWitnesses(t Transaction) []witness.Witness {
-	return []witness.Witness{}
-}