core: export UtilityTokenID and GoverningTokenID

Both are very useful outside of the core, this change also makes respective
transactions initialize with the package as they don't depend on any kind of
input and it makes no sense recreating them again and again on every use.

pkg/core/blockchain.go

@@ -432,7 +432,7 @@ func (bc *Blockchain) storeBlock(block *block.Block) error {
 					return err
 				}
 
-				if prevTXOutput.AssetID.Equals(governingTokenTX().Hash()) {
+				if prevTXOutput.AssetID.Equals(GoverningTokenID()) {
 					spentCoin := NewSpentCoinState(input.PrevHash, prevTXHeight)
 					spentCoin.items[input.PrevIndex] = block.Index
 					if err = cache.PutSpentCoinState(input.PrevHash, spentCoin); err != nil {
@@ -648,14 +648,14 @@ func processOutputs(tx *transaction.Transaction, dao *cachedDao) error {
 }
 
 func processTXWithValidatorsAdd(output *transaction.Output, account *state.Account, dao *cachedDao) error {
-	if output.AssetID.Equals(governingTokenTX().Hash()) && len(account.Votes) > 0 {
+	if output.AssetID.Equals(GoverningTokenID()) && len(account.Votes) > 0 {
 		return modAccountVotes(account, dao, output.Amount)
 	}
 	return nil
 }
 
 func processTXWithValidatorsSubtract(output *transaction.Output, account *state.Account, dao *cachedDao) error {
-	if output.AssetID.Equals(governingTokenTX().Hash()) && len(account.Votes) > 0 {
+	if output.AssetID.Equals(GoverningTokenID()) && len(account.Votes) > 0 {
 		return modAccountVotes(account, dao, -output.Amount)
 	}
 	return nil
@@ -724,7 +724,7 @@ func processAccountStateDescriptor(descriptor *transaction.StateDescriptor, dao
 	}
 
 	if descriptor.Field == "Votes" {
-		balance := account.GetBalanceValues()[governingTokenTX().Hash()]
+		balance := account.GetBalanceValues()[GoverningTokenID()]
 		if err = modAccountVotes(account, dao, -balance); err != nil {
 			return err
 		}
@@ -999,14 +999,14 @@ func (bc *Blockchain) FeePerByte(t *transaction.Transaction) util.Fixed8 {
 func (bc *Blockchain) NetworkFee(t *transaction.Transaction) util.Fixed8 {
 	inputAmount := util.Fixed8FromInt64(0)
 	for _, txOutput := range bc.References(t) {
-		if txOutput.AssetID == utilityTokenTX().Hash() {
+		if txOutput.AssetID == UtilityTokenID() {
 			inputAmount.Add(txOutput.Amount)
 		}
 	}
 
 	outputAmount := util.Fixed8FromInt64(0)
 	for _, txOutput := range t.Outputs {
-		if txOutput.AssetID == utilityTokenTX().Hash() {
+		if txOutput.AssetID == UtilityTokenID() {
 			outputAmount.Add(txOutput.Amount)
 		}
 	}
@@ -1192,7 +1192,7 @@ func (bc *Blockchain) verifyResults(t *transaction.Transaction) error {
 	if len(resultsDestroy) > 1 {
 		return errors.New("tx has more than 1 destroy output")
 	}
-	if len(resultsDestroy) == 1 && resultsDestroy[0].AssetID != utilityTokenTX().Hash() {
+	if len(resultsDestroy) == 1 && resultsDestroy[0].AssetID != UtilityTokenID() {
 		return errors.New("tx destroys non-utility token")
 	}
 	sysfee := bc.SystemFee(t)
@@ -1208,14 +1208,14 @@ func (bc *Blockchain) verifyResults(t *transaction.Transaction) error {
 	switch t.Type {
 	case transaction.MinerType, transaction.ClaimType:
 		for _, r := range resultsIssue {
-			if r.AssetID != utilityTokenTX().Hash() {
+			if r.AssetID != UtilityTokenID() {
 				return errors.New("miner or claim tx issues non-utility tokens")
 			}
 		}
 		break
 	case transaction.IssueType:
 		for _, r := range resultsIssue {
-			if r.AssetID == utilityTokenTX().Hash() {
+			if r.AssetID == UtilityTokenID() {
 				return errors.New("issue tx issues utility tokens")
 			}
 		}

pkg/core/util.go

@@ -13,6 +13,17 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/vm/opcode"
 )
 
+var (
+	// governingTokenTX represents transaction that is used to create
+	// governing (NEO) token. It's a part of the genesis block.
+	governingTokenTX transaction.Transaction
+
+	// utilityTokenTX represents transaction that is used to create
+	// utility (GAS) token. It's a part of the genesis block. It's mostly
+	// useful for its hash that represents GAS asset ID.
+	utilityTokenTX transaction.Transaction
+)
+
 // createGenesisBlock creates a genesis block based on the given configuration.
 func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error) {
 	validators, err := getValidators(cfg)
@@ -38,8 +49,6 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error)
 		},
 	}
 
-	governingTX := governingTokenTX()
-	utilityTX := utilityTokenTX()
 	rawScript, err := smartcontract.CreateMultiSigRedeemScript(
 		len(cfg.StandbyValidators)/2+1,
 		validators,
@@ -62,16 +71,16 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error)
 				Outputs:    []transaction.Output{},
 				Scripts:    []transaction.Witness{},
 			},
-			governingTX,
-			utilityTX,
+			&governingTokenTX,
+			&utilityTokenTX,
 			{
 				Type:   transaction.IssueType,
 				Data:   &transaction.IssueTX{}, // no fields.
 				Inputs: []transaction.Input{},
 				Outputs: []transaction.Output{
 					{
-						AssetID:    governingTX.Hash(),
-						Amount:     governingTX.Data.(*transaction.RegisterTX).Amount,
+						AssetID:    governingTokenTX.Hash(),
+						Amount:     governingTokenTX.Data.(*transaction.RegisterTX).Amount,
 						ScriptHash: scriptOut,
 					},
 				},
@@ -92,7 +101,7 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error)
 	return b, nil
 }
 
-func governingTokenTX() *transaction.Transaction {
+func init() {
 	admin := hash.Hash160([]byte{byte(opcode.PUSHT)})
 	registerTX := &transaction.RegisterTX{
 		AssetType: transaction.GoverningToken,
@@ -102,7 +111,7 @@ func governingTokenTX() *transaction.Transaction {
 		Admin:     admin,
 	}
 
-	tx := &transaction.Transaction{
+	governingTokenTX = transaction.Transaction{
 		Type:       transaction.RegisterType,
 		Data:       registerTX,
 		Attributes: []transaction.Attribute{},
@@ -111,19 +120,15 @@ func governingTokenTX() *transaction.Transaction {
 		Scripts:    []transaction.Witness{},
 	}
 
-	return tx
-}
-
-func utilityTokenTX() *transaction.Transaction {
-	admin := hash.Hash160([]byte{byte(opcode.PUSHF)})
-	registerTX := &transaction.RegisterTX{
+	admin = hash.Hash160([]byte{byte(opcode.PUSHF)})
+	registerTX = &transaction.RegisterTX{
 		AssetType: transaction.UtilityToken,
 		Name:      "[{\"lang\":\"zh-CN\",\"name\":\"小蚁币\"},{\"lang\":\"en\",\"name\":\"AntCoin\"}]",
 		Amount:    calculateUtilityAmount(),
 		Precision: 8,
 		Admin:     admin,
 	}
-	tx := &transaction.Transaction{
+	utilityTokenTX = transaction.Transaction{
 		Type:       transaction.RegisterType,
 		Data:       registerTX,
 		Attributes: []transaction.Attribute{},
@@ -131,8 +136,16 @@ func utilityTokenTX() *transaction.Transaction {
 		Outputs:    []transaction.Output{},
 		Scripts:    []transaction.Witness{},
 	}
+}
 
-	return tx
+// GoverningTokenID returns the governing token (NEO) hash.
+func GoverningTokenID() util.Uint256 {
+	return governingTokenTX.Hash()
+}
+
+// UtilityTokenID returns the utility token (GAS) hash.
+func UtilityTokenID() util.Uint256 {
+	return utilityTokenTX.Hash()
 }
 
 func getValidators(cfg config.ProtocolConfiguration) ([]*keys.PublicKey, error) {

pkg/core/util_test.go

@@ -50,12 +50,10 @@ func TestGetConsensusAddressMainNet(t *testing.T) {
 
 func TestUtilityTokenTX(t *testing.T) {
 	expect := "602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7"
-	tx := utilityTokenTX()
-	assert.Equal(t, expect, tx.Hash().StringLE())
+	assert.Equal(t, expect, UtilityTokenID().StringLE())
 }
 
 func TestGoverningTokenTX(t *testing.T) {
 	expect := "c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b"
-	tx := governingTokenTX()
-	assert.Equal(t, expect, tx.Hash().StringLE())
+	assert.Equal(t, expect, GoverningTokenID().StringLE())
 }

pkg/rpc/rpc.go

@@ -4,6 +4,7 @@ import (
 	"encoding/hex"
 	"fmt"
 
+	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
 	"github.com/CityOfZion/neo-go/pkg/smartcontract"
@@ -160,15 +161,12 @@ func (c *Client) SignAndPushInvocationTx(script []byte, wif *keys.WIF, gas util.
 	var txHash util.Uint256
 	var err error
 
-	gasIDB, _ := hex.DecodeString("602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7")
-	gasID, _ := util.Uint256DecodeBytesLE(gasIDB)
-
 	tx := transaction.NewInvocationTX(script, gas)
 
 	fromAddress := wif.PrivateKey.Address()
 
 	if gas > 0 {
-		if err = AddInputsAndUnspentsToTx(tx, fromAddress, gasID, gas, c); err != nil {
+		if err = AddInputsAndUnspentsToTx(tx, fromAddress, core.UtilityTokenID(), gas, c); err != nil {
 			return txHash, errors.Wrap(err, "failed to add inputs and unspents to transaction")
 		}
 	}