Merge pull request #2290 from nspcc-dev/microopt

Trivial microoptimizations

pkg/core/native/native_gas.go

@@ -54,7 +54,7 @@ func (g *GAS) increaseBalance(_ *interop.Context, _ util.Uint160, si *state.Stor
 			err = errors.New("insufficient funds")
 		}
 		return err
-	} else if sign == -1 && acc.Balance.Cmp(new(big.Int).Neg(amount)) == -1 {
+	} else if sign == -1 && acc.Balance.CmpAbs(amount) == -1 {
 		return errors.New("insufficient funds")
 	}
 	acc.Balance.Add(&acc.Balance, amount)

pkg/core/native/native_neo.go

@@ -405,7 +405,7 @@ func (n *NEO) increaseBalance(ic *interop.Context, h util.Uint160, si *state.Sto
 	if err != nil {
 		return err
 	}
-	if (amount.Sign() == -1 && acc.Balance.Cmp(new(big.Int).Neg(amount)) == -1) ||
+	if (amount.Sign() == -1 && acc.Balance.CmpAbs(amount) == -1) ||
 		(amount.Sign() == 0 && checkBal != nil && acc.Balance.Cmp(checkBal) == -1) {
 		return errors.New("insufficient funds")
 	}

pkg/core/native/native_nep17.go

@@ -262,7 +262,9 @@ func (c *nep17TokenNative) burn(ic *interop.Context, h util.Uint160, amount *big
 	if amount.Sign() == 0 {
 		return
 	}
-	c.addTokens(ic, h, new(big.Int).Neg(amount))
+	amount.Neg(amount)
+	c.addTokens(ic, h, amount)
+	amount.Neg(amount)
 	c.postTransfer(ic, &h, nil, amount, stackitem.Null{}, false)
 }
 

pkg/core/transaction/transaction.go

@@ -68,6 +68,9 @@ type Transaction struct {
 	// Hash of the transaction (double SHA256).
 	hash util.Uint256
 
+	// Whether hash is correct.
+	hashed bool
+
 	// Trimmed indicates this is a transaction from trimmed
 	// data.
 	Trimmed bool
@@ -78,6 +81,7 @@ type Transaction struct {
 func NewTrimmedTX(hash util.Uint256) *Transaction {
 	return &Transaction{
 		hash:    hash,
+		hashed:  true,
 		Trimmed: true,
 	}
 }
@@ -98,7 +102,7 @@ func New(script []byte, gas int64) *Transaction {
 
 // Hash returns the hash of the transaction.
 func (t *Transaction) Hash() util.Uint256 {
-	if t.hash.Equals(util.Uint256{}) {
+	if !t.hashed {
 		if t.createHash() != nil {
 			panic("failed to compute hash!")
 		}
@@ -172,6 +176,7 @@ func (t *Transaction) decodeHashableFields(br *io.BinReader, buf []byte) {
 	if buf != nil {
 		end = len(buf) - br.Len()
 		t.hash = hash.Sha256(buf[start:end])
+		t.hashed = true
 	}
 }
 
@@ -261,6 +266,7 @@ func (t *Transaction) createHash() error {
 	}
 
 	shaHash.Sum(t.hash[:0])
+	t.hashed = true
 	return nil
 }
 

pkg/core/transaction/transaction_test.go

@@ -308,3 +308,17 @@ func TestTransaction_HasSigner(t *testing.T) {
 	require.True(t, tx.HasSigner(u1))
 	require.False(t, tx.HasSigner(util.Uint160{}))
 }
+
+func BenchmarkTxHash(b *testing.B) {
+	script := []byte{0x51}
+	tx := New(script, 1)
+	tx.NetworkFee = 123
+	tx.Signers = []Signer{{Account: util.Uint160{1, 2, 3}}}
+	tx.Scripts = []Witness{{InvocationScript: []byte{}, VerificationScript: []byte{}}}
+
+	// Prime cache.
+	tx.Hash()
+	for i := 0; i < b.N; i++ {
+		_ = tx.Hash()
+	}
+}

pkg/crypto/hash/hash.go

@@ -53,7 +53,7 @@ func RipeMD160(data []byte) util.Uint160 {
 	hasher := ripemd160.New()
 	_, _ = hasher.Write(data)
 
-	hash, _ = util.Uint160DecodeBytesBE(hasher.Sum(nil))
+	hasher.Sum(hash[:0])
 	return hash
 }
 

pkg/vm/vm.go

@@ -317,7 +317,9 @@ func (v *VM) loadScriptWithCallingHash(b []byte, exe *nef.File, caller util.Uint
 
 	v.checkInvocationStackSize()
 	ctx := NewContextWithParams(b, rvcount, offset)
+	if rvcount != -1 || v.estack.Len() != 0 {
 		v.estack = newStack("evaluation", &v.refs)
+	}
 	ctx.estack = v.estack
 	initStack(&ctx.tryStack, "exception", nil)
 	ctx.callFlag = f