[FIX] Formatting and code-style (#118)

* [FIX] Formatting and code-style

- gofmt
- import resort
- prealloc slices
- simplify code

* fix vet

cli/main.go

@@ -22,5 +22,7 @@ func main() {
 		vm.NewCommand(),
 	}
 
-	ctl.Run(os.Args)
+	if err := ctl.Run(os.Args); err != nil {
+		panic(err)
+	}
 }

pkg/core/blockchain.go

@@ -8,8 +8,6 @@ import (
 	"time"
 
 	"github.com/CityOfZion/neo-go/config"
-	//"github.com/CityOfZion/neo-go/pkg/core"
-
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -104,7 +102,9 @@ func (bc *Blockchain) init() error {
 	ver, err := storage.Version(bc.Store)
 	if err != nil {
 		log.Infof("no storage version found! creating genesis block")
-		storage.PutVersion(bc.Store, version)
+		if err = storage.PutVersion(bc.Store, version); err != nil {
+			return err
+		}
 		return bc.persistBlock(genesisBlock)
 	}
 	if ver != version {
@@ -284,11 +284,17 @@ func (bc *Blockchain) persistBlock(block *Block) error {
 		assets       = make(Assets)
 	)
 
-	storeAsBlock(batch, block, 0)
+	if err := storeAsBlock(batch, block, 0); err != nil {
+		return err
+	}
+
 	storeAsCurrentBlock(batch, block)
 
 	for _, tx := range block.Transactions {
-		storeAsTransaction(batch, tx, block.Index)
+		if err := storeAsTransaction(batch, tx, block.Index); err != nil {
+			return err
+		}
+
 		unspentCoins[tx.Hash()] = NewUnspentCoinState(len(tx.Outputs))
 
 		// Process TX outputs.

pkg/core/header.go

@@ -21,7 +21,10 @@ func (h *Header) DecodeBinary(r io.Reader) error {
 	}
 
 	var padding uint8
-	binary.Read(r, binary.LittleEndian, &padding)
+	if err := binary.Read(r, binary.LittleEndian, &padding); err != nil {
+		return err
+	}
+
 	if padding != 0 {
 		return fmt.Errorf("format error: padding must equal 0 got %d", padding)
 	}

pkg/core/storage/memory_store.go

@@ -51,7 +51,9 @@ func (s *MemoryStore) Put(key, value []byte) error {
 func (s *MemoryStore) PutBatch(batch Batch) error {
 	b := batch.(*MemoryBatch)
 	for k, v := range b.m {
-		s.Put(*k, v)
+		if err := s.Put(*k, v); err != nil {
+			return err
+		}
 	}
 	return nil
 }

pkg/core/storage/memory_store_test.go

@@ -13,7 +13,9 @@ func TestGetPut(t *testing.T) {
 		value = []byte("rocks")
 	)
 
-	s.Put(key, value)
+	if err := s.Put(key, value); err != nil {
+		t.Fatal(err)
+	}
 
 	newVal, err := s.Get(key)
 	if err != nil {
@@ -43,7 +45,10 @@ func TestPutBatch(t *testing.T) {
 
 	batch.Put(key, value)
 
-	s.PutBatch(batch)
+	if err := s.PutBatch(batch); err != nil {
+		t.Fatal(err)
+	}
+
 	newVal, err := s.Get(key)
 	if err != nil {
 		t.Fatal(err)

pkg/core/util.go

@@ -89,7 +89,9 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*Block, error) {
 		},
 	}
 
-	block.rebuildMerkleRoot()
+	if err = block.rebuildMerkleRoot(); err != nil {
+		return nil, err
+	}
 
 	return block, nil
 }

pkg/crypto/base58.go

@@ -5,6 +5,8 @@ import (
 	"crypto/sha256"
 	"fmt"
 	"math/big"
+
+	"github.com/pkg/errors"
 )
 
 const prefix rune = '1'
@@ -54,7 +56,7 @@ func Base58Decode(s string) ([]byte, error) {
 	}
 
 	out := n.Bytes()
-	buf := make([]byte, (zero + len(out)))
+	buf := make([]byte, zero+len(out))
 	copy(buf[zero:], out[:])
 
 	return buf, nil
@@ -94,7 +96,7 @@ func Base58CheckDecode(s string) (b []byte, err error) {
 	}
 
 	if len(b) < 5 {
-		return nil, fmt.Errorf("Invalid base-58 check string: missing checksum.")
+		return nil, errors.New("invalid base-58 check string: missing checksum.")
 	}
 
 	sha := sha256.New()
@@ -106,7 +108,7 @@ func Base58CheckDecode(s string) (b []byte, err error) {
 	hash = sha.Sum(nil)
 
 	if bytes.Compare(hash[0:4], b[len(b)-4:]) != 0 {
-		return nil, fmt.Errorf("Invalid base-58 check string: invalid checksum.")
+		return nil, errors.New("invalid base-58 check string: invalid checksum.")
 	}
 
 	// Strip the 4 byte long hash.

pkg/network/message.go

@@ -260,7 +260,7 @@ func cmdToByteArray(cmd CommandType) [cmdSize]byte {
 }
 
 func cmdByteArrayToString(cmd [cmdSize]byte) string {
-	buf := []byte{}
+	buf := make([]byte, 0, cmdSize)
 	for i := 0; i < cmdSize; i++ {
 		if cmd[i] != 0 {
 			buf = append(buf, cmd[i])

pkg/network/payload/headers_test.go

@@ -11,7 +11,7 @@ import (
 
 func TestHeadersEncodeDecode(t *testing.T) {
 	headers := &Headers{[]*core.Header{
-		&core.Header{
+		{
 			BlockBase: core.BlockBase{
 				Version: 0,
 				Index:   1,
@@ -20,7 +20,7 @@ func TestHeadersEncodeDecode(t *testing.T) {
 					VerificationScript: []byte{0x1},
 				},
 			}},
-		&core.Header{
+		{
 			BlockBase: core.BlockBase{
 				Version: 0,
 				Index:   2,
@@ -29,7 +29,7 @@ func TestHeadersEncodeDecode(t *testing.T) {
 					VerificationScript: []byte{0x1},
 				},
 			}},
-		&core.Header{
+		{
 			BlockBase: core.BlockBase{
 				Version: 0,
 				Index:   3,

pkg/network/server.go

@@ -242,8 +242,7 @@ func (s *Server) handleInvCmd(p Peer, inv *payload.Inventory) error {
 		return errInvalidInvType
 	}
 	payload := payload.NewInventory(inv.Type, inv.Hashes)
-	p.WriteMsg(NewMessage(s.Net, CMDGetData, payload))
+	return p.WriteMsg(NewMessage(s.Net, CMDGetData, payload))
-	return nil
 }
 
 // requestHeaders will send a getheaders message to the peer.

pkg/network/server_config.go

@@ -56,8 +56,8 @@ func NewServerConfig(cfg config.Config) ServerConfig {
 		Net:               protoConfig.Magic,
 		Relay:             appConfig.Relay,
 		Seeds:             protoConfig.SeedList,
-		DialTimeout:       (appConfig.DialTimeout * time.Second),
+		DialTimeout:       appConfig.DialTimeout * time.Second,
-		ProtoTickInterval: (appConfig.ProtoTickInterval * time.Second),
+		ProtoTickInterval: appConfig.ProtoTickInterval * time.Second,
 		MaxPeers:          appConfig.MaxPeers,
 	}
 }

pkg/network/server_test.go

@@ -28,7 +28,9 @@ func TestSendVersion(t *testing.T) {
 		assert.Equal(t, uint32(0), version.StartHeight)
 	}
 
-	s.sendVersion(p)
+	if err := s.sendVersion(p); err != nil {
+		t.Fatal(err)
+	}
 }
 
 // Server should reply with a verack after receiving a valid version.

pkg/rpc/client.go

@@ -128,7 +128,7 @@ func (c *Client) performRequest(method string, p params, v interface{}) error {
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return fmt.Errorf("Remote responded with a non 200 response: %d", resp.StatusCode)
+		return fmt.Errorf("remote responded with a non 200 response: %d", resp.StatusCode)
 	}
 
 	return json.NewDecoder(resp.Body).Decode(v)

pkg/rpc/neoScanBalanceGetter.go

@@ -29,12 +29,7 @@ func (s NeoScanServer) GetBalance(address string) ([]*Unspent, error) {
 		return nil, errs.Wrap(err, "Failed to perform HTTP request")
 	}
 
-	defer func() error {
+	defer res.Body.Close()
-		if err := res.Body.Close(); err != nil {
-			return err
-		}
-		return nil
-	}()
 
 	if err = json.NewDecoder(res.Body).Decode(&balance); err != nil {
 		return nil, errs.Wrap(err, "Failed to decode HTTP response")
@@ -78,7 +73,7 @@ func (s NeoScanServer) CalculateInputs(address string, assetIdUint util.Uint256,
 		num++
 	}
 	if selected < required {
-		return nil, util.Fixed8(0), errors.New("Cannot compose inputs for transaction; check sender balance")
+		return nil, util.Fixed8(0), errors.New("cannot compose inputs for transaction; check sender balance")
 	}
 
 	inputs := make([]transaction.Input, 0, num)

pkg/rpc/request.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"net/http"
 
+	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -47,11 +48,11 @@ func (r *Request) DecodeData(data io.ReadCloser) error {
 
 	err := json.NewDecoder(data).Decode(r)
 	if err != nil {
-		return fmt.Errorf("Error parsing JSON payload: %s", err)
+		return errors.Errorf("error parsing JSON payload: %s", err)
 	}
 
 	if r.JSONRPC != jsonRPCVersion {
-		return fmt.Errorf("Invalid version, expected 2.0 got: '%s'", r.JSONRPC)
+		return errors.Errorf("invalid version, expected 2.0 got: '%s'", r.JSONRPC)
 	}
 
 	return nil
@@ -64,7 +65,7 @@ func (r *Request) Params() (*Params, error) {
 
 	err := json.Unmarshal(r.RawParams, &params)
 	if err != nil {
-		return nil, fmt.Errorf("Error parsing params field in payload: %s", err)
+		return nil, errors.Errorf("error parsing params field in payload: %s", err)
 	}
 
 	return &params, nil

pkg/rpc/server.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"strconv"
 
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/network"
@@ -33,7 +34,7 @@ var (
 func NewServer(chain core.Blockchainer, port uint16, coreServer *network.Server) Server {
 	return Server{
 		Server: &http.Server{
-			Addr: fmt.Sprintf(":%d", port),
+			Addr: ":" + strconv.FormatUint(uint64(port), 10),
 		},
 		chain:      chain,
 		coreServer: coreServer,

pkg/rpc/server_test.go

@@ -9,9 +9,8 @@ import (
 	"strconv"
 	"testing"
 
-	"github.com/CityOfZion/neo-go/pkg/core"
-
 	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/network"
 	"github.com/stretchr/testify/assert"
 )
@@ -25,12 +24,12 @@ func TestHandler(t *testing.T) {
 
 	cfg, err := config.Load(configPath, net)
 	if err != nil {
-		t.Errorf("could not load configuration file")
+		t.Fatal("could not create levelDB chain", err)
 	}
 
 	chain, err := core.NewBlockchainLevelDB(cfg)
 	if err != nil {
-		t.Errorf("could not create levelDB chain")
+		t.Fatal("could not create levelDB chain", err)
 	}
 
 	serverConfig := network.NewServerConfig(cfg)

pkg/rpc/stack_param.go

@@ -84,16 +84,16 @@ func StackParamTypeFromString(s string) (StackParamType, error) {
 	}
 }
 
-func (p *StackParamType) UnmarshalJSON(data []byte) (err error) {
+func (t *StackParamType) UnmarshalJSON(data []byte) (err error) {
 	var (
 		s = string(data)
 		l = len(s)
 	)
 	if l < 2 || s[0] != '"' || s[l-1] != '"' {
-		*p = Unknown
+		*t = Unknown
 		return errors.Errorf("invalid type: %s", s)
 	}
-	*p, err = StackParamTypeFromString(s[1 : l-1])
+	*t, err = StackParamTypeFromString(s[1 : l-1])
 	return
 }
 

pkg/rpc/txBuilder.go

@@ -77,8 +77,8 @@ func GetInvocationScript(tx *transaction.Transaction, wif wallet.WIF) ([]byte, e
 	if err = tx.EncodeBinary(buf); err != nil {
 		return nil, errs.Wrap(err, "Failed to encode transaction to binary")
 	}
-	bytes := buf.Bytes()
+	data := buf.Bytes()
-	signature, err = wif.PrivateKey.Sign(bytes[:(len(bytes) - 1)])
+	signature, err = wif.PrivateKey.Sign(data[:(len(data) - 1)])
 	if err != nil {
 		return nil, errs.Wrap(err, "Failed ti sign transaction with private key")
 	}

pkg/rpc/txTypes.go

@@ -39,4 +39,3 @@ type (
 		GetBalance(address string) ([]*Unspent, error)
 	}
 )
-

pkg/rpc/types.go

@@ -14,7 +14,7 @@ type InvokeResult struct {
 	State       string `json:"state"`
 	GasConsumed string `json:"gas_consumed"`
 	Script      string `json:"script"`
-	Stack       []*StackParam
+	Stack       []StackParam
 }
 
 // AccountStateResponse holds the getaccountstate response.

pkg/smartcontract/contract.go

@@ -22,13 +22,21 @@ func CreateMultiSigRedeemScript(m int, publicKeys crypto.PublicKeys) ([]byte, er
 	}
 
 	buf := new(bytes.Buffer)
-	vm.EmitInt(buf, int64(m))
+	if err := vm.EmitInt(buf, int64(m)); err != nil {
+		return nil, err
+	}
 	sort.Sort(publicKeys)
 	for _, pubKey := range publicKeys {
-		vm.EmitBytes(buf, pubKey.Bytes())
+		if err := vm.EmitBytes(buf, pubKey.Bytes()); err != nil {
+			return nil, err
+		}
+	}
+	if err := vm.EmitInt(buf, int64(len(publicKeys))); err != nil {
+		return nil, err
+	}
+	if err := vm.EmitOpcode(buf, vm.Ocheckmultisig); err != nil {
+		return nil, err
 	}
-	vm.EmitInt(buf, int64(len(publicKeys)))
-	vm.EmitOpcode(buf, vm.Ocheckmultisig)
 
 	return buf.Bytes(), nil
 }

pkg/util/uint160.go

@@ -33,9 +33,7 @@ func Uint160DecodeBytes(b []byte) (u Uint160, err error) {
 	if len(b) != uint160Size {
 		return u, fmt.Errorf("expected byte size of %d got %d", uint160Size, len(b))
 	}
-	for i := 0; i < uint160Size; i++ {
+	copy(u[:], b)
-		u[i] = b[i]
-	}
 	return
 }
 

pkg/util/uint256.go

@@ -30,9 +30,7 @@ func Uint256DecodeBytes(b []byte) (u Uint256, err error) {
 	if len(b) != uint256Size {
 		return u, fmt.Errorf("expected []byte of size %d got %d", uint256Size, len(b))
 	}
-	for i := 0; i < uint256Size; i++ {
+	copy(u[:], b)
-		u[i] = b[i]
-	}
 	return u, nil
 }
 

pkg/vm/cli/cli.go

@@ -188,7 +188,7 @@ func (c *VMCLI) Run() error {
 		if len(input) != 0 {
 			parts := strings.Split(input, " ")
 			cmd := parts[0]
-			args := []string{}
+			var args []string
 			if len(parts) > 1 {
 				args = parts[1:]
 			}

pkg/vm/compiler/emit.go

@@ -38,7 +38,7 @@ func emitInt(w *bytes.Buffer, i int64) error {
 		return emitOpcode(w, vm.Opushf)
 	}
 	if i > 0 && i < 16 {
-		val := vm.Opcode((int(vm.Opush1) - 1 + int(i)))
+		val := vm.Opcode(int(vm.Opush1) - 1 + int(i))
 		return emitOpcode(w, val)
 	}
 
@@ -83,7 +83,7 @@ func emitSyscall(w *bytes.Buffer, api string) error {
 	}
 	buf := make([]byte, len(api)+1)
 	buf[0] = byte(len(api))
-	copy(buf[1:len(buf)], []byte(api))
+	copy(buf[1:], []byte(api))
 	return emit(w, vm.Osyscall, buf)
 }
 

pkg/vm/emit.go

@@ -41,7 +41,7 @@ func EmitInt(w *bytes.Buffer, i int64) error {
 		return EmitOpcode(w, Opushf)
 	}
 	if i > 0 && i < 16 {
-		val := Opcode((int(Opush1) - 1 + int(i)))
+		val := Opcode(int(Opush1) - 1 + int(i))
 		return EmitOpcode(w, val)
 	}
 

pkg/vm/opcode.go

@@ -9,7 +9,7 @@ type Opcode byte
 const (
 	// Constants
 	Opush0       Opcode = 0x00 // An empty array of bytes is pushed onto the stack.
-	Opushf       Opcode = Opush0
+	Opushf              = Opush0
 	Opushbytes1  Opcode = 0x01 // 0x01-0x4B The next opcode bytes is data to be pushed onto the stack
 	Opushbytes75 Opcode = 0x4B
 	Opushdata1   Opcode = 0x4C // The next byte contains the number of bytes to be pushed onto the stack.
@@ -17,7 +17,7 @@ const (
 	Opushdata4   Opcode = 0x4E // The next four bytes contain the number of bytes to be pushed onto the stack.
 	Opushm1      Opcode = 0x4F // The number -1 is pushed onto the stack.
 	Opush1       Opcode = 0x51
-	Opusht       Opcode = Opush1
+	Opusht              = Opush1
 	Opush2       Opcode = 0x52 // The number 2 is pushed onto the stack.
 	Opush3       Opcode = 0x53 // The number 3 is pushed onto the stack.
 	Opush4       Opcode = 0x54 // The number 4 is pushed onto the stack.

pkg/vm/vm_test.go

@@ -60,7 +60,7 @@ func TestPushBytes1to75(t *testing.T) {
 }
 
 func TestPushm1to16(t *testing.T) {
-	prog := []byte{}
+	var prog []byte
 	for i := int(Opushm1); i <= int(Opush16); i++ {
 		if i == 80 {
 			continue // opcode layout we got here.

pkg/wallet/wif.go

@@ -107,4 +107,3 @@ func (wif WIF) GetVerificationScript() ([]byte, error) {
 	vScript = append(vScript, checksig)
 	return vScript, nil
 }
-