fix golint issues in core/codec (#473)

core/codec/aesecb.go

@@ -10,6 +10,7 @@ import (
 	"github.com/tal-tech/go-zero/core/logx"
 )
 
+// ErrPaddingSize indicates bad padding size.
 var ErrPaddingSize = errors.New("padding size error")
 
 type ecb struct {
@@ -26,6 +27,7 @@ func newECB(b cipher.Block) *ecb {
 
 type ecbEncrypter ecb
 
+// NewECBEncrypter returns an ECB encrypter.
 func NewECBEncrypter(b cipher.Block) cipher.BlockMode {
 	return (*ecbEncrypter)(newECB(b))
 }
@@ -52,6 +54,7 @@ func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
 
 type ecbDecrypter ecb
 
+// NewECBDecrypter returns an ECB decrypter.
 func NewECBDecrypter(b cipher.Block) cipher.BlockMode {
 	return (*ecbDecrypter)(newECB(b))
 }
@@ -78,6 +81,7 @@ func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
 	}
 }
 
+// EcbDecrypt decrypts src with the given key.
 func EcbDecrypt(key, src []byte) ([]byte, error) {
 	block, err := aes.NewCipher(key)
 	if err != nil {
@@ -92,6 +96,8 @@ func EcbDecrypt(key, src []byte) ([]byte, error) {
 	return pkcs5Unpadding(decrypted, decrypter.BlockSize())
 }
 
+// EcbDecryptBase64 decrypts base64 encoded src with the given base64 encoded key.
+// The returned string is also base64 encoded.
 func EcbDecryptBase64(key, src string) (string, error) {
 	keyBytes, err := getKeyBytes(key)
 	if err != nil {
@@ -111,6 +117,7 @@ func EcbDecryptBase64(key, src string) (string, error) {
 	return base64.StdEncoding.EncodeToString(decryptedBytes), nil
 }
 
+// EcbEncrypt encrypts src with the given key.
 func EcbEncrypt(key, src []byte) ([]byte, error) {
 	block, err := aes.NewCipher(key)
 	if err != nil {
@@ -126,6 +133,8 @@ func EcbEncrypt(key, src []byte) ([]byte, error) {
 	return crypted, nil
 }
 
+// EcbEncryptBase64 encrypts base64 encoded src with the given base64 encoded key.
+// The returned string is also base64 encoded.
 func EcbEncryptBase64(key, src string) (string, error) {
 	keyBytes, err := getKeyBytes(key)
 	if err != nil {

core/codec/dh.go

@@ -11,8 +11,11 @@ import (
 // 2048-bit MODP Group
 
 var (
-	ErrInvalidPriKey    = errors.New("invalid private key")
-	ErrInvalidPubKey    = errors.New("invalid public key")
+	// ErrInvalidPriKey indicates the invalid private key.
+	ErrInvalidPriKey = errors.New("invalid private key")
+	// ErrInvalidPubKey indicates the invalid public key.
+	ErrInvalidPubKey = errors.New("invalid public key")
+	// ErrPubKeyOutOfBound indicates the public key is out of bound.
 	ErrPubKeyOutOfBound = errors.New("public key out of bound")
 
 	p, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF", 16)
@@ -20,11 +23,13 @@ var (
 	zero = big.NewInt(0)
 )
 
+// DhKey defines the Diffie Hellman key.
 type DhKey struct {
 	PriKey *big.Int
 	PubKey *big.Int
 }
 
+// ComputeKey returns a key from public key and private key.
 func ComputeKey(pubKey, priKey *big.Int) (*big.Int, error) {
 	if pubKey == nil {
 		return nil, ErrInvalidPubKey
@@ -41,6 +46,7 @@ func ComputeKey(pubKey, priKey *big.Int) (*big.Int, error) {
 	return new(big.Int).Exp(pubKey, priKey, p), nil
 }
 
+// GenerateKey returns a Diffie Hellman key.
 func GenerateKey() (*DhKey, error) {
 	var err error
 	var x *big.Int
@@ -63,10 +69,12 @@ func GenerateKey() (*DhKey, error) {
 	return key, nil
 }
 
+// NewPublicKey returns a public key from the given bytes.
 func NewPublicKey(bs []byte) *big.Int {
 	return new(big.Int).SetBytes(bs)
 }
 
+// Bytes returns public key bytes.
 func (k *DhKey) Bytes() []byte {
 	if k.PubKey == nil {
 		return nil

core/codec/gzip.go

@@ -8,6 +8,7 @@ import (
 
 const unzipLimit = 100 * 1024 * 1024 // 100MB
 
+// Gzip compresses bs.
 func Gzip(bs []byte) []byte {
 	var b bytes.Buffer
 
@@ -18,6 +19,7 @@ func Gzip(bs []byte) []byte {
 	return b.Bytes()
 }
 
+// Gunzip uncompresses bs.
 func Gunzip(bs []byte) ([]byte, error) {
 	r, err := gzip.NewReader(bytes.NewBuffer(bs))
 	if err != nil {

core/codec/hmac.go

@@ -7,12 +7,14 @@ import (
 	"io"
 )
 
+// Hmac returns HMAC bytes for body with the given key.
 func Hmac(key []byte, body string) []byte {
 	h := hmac.New(sha256.New, key)
 	io.WriteString(h, body)
 	return h.Sum(nil)
 }
 
+// HmacBase64 returns the base64 encoded string of HMAC for body with the given key.
 func HmacBase64(key []byte, body string) string {
 	return base64.StdEncoding.EncodeToString(Hmac(key, body))
 }

core/codec/rsa.go

@@ -11,17 +11,22 @@ import (
 )
 
 var (
+	// ErrPrivateKey indicates the invalid private key.
 	ErrPrivateKey = errors.New("private key error")
-	ErrPublicKey  = errors.New("failed to parse PEM block containing the public key")
-	ErrNotRsaKey  = errors.New("key type is not RSA")
+	// ErrPublicKey indicates the invalid public key.
+	ErrPublicKey = errors.New("failed to parse PEM block containing the public key")
+	// ErrNotRsaKey indicates the invalid RSA key.
+	ErrNotRsaKey = errors.New("key type is not RSA")
 )
 
 type (
+	// RsaDecrypter represents a RSA decrypter.
 	RsaDecrypter interface {
 		Decrypt(input []byte) ([]byte, error)
 		DecryptBase64(input string) ([]byte, error)
 	}
 
+	// RsaEncrypter represents a RSA encrypter.
 	RsaEncrypter interface {
 		Encrypt(input []byte) ([]byte, error)
 	}
@@ -41,6 +46,7 @@ type (
 	}
 )
 
+// NewRsaDecrypter returns a RsaDecrypter with the given file.
 func NewRsaDecrypter(file string) (RsaDecrypter, error) {
 	content, err := ioutil.ReadFile(file)
 	if err != nil {
@@ -84,6 +90,7 @@ func (r *rsaDecrypter) DecryptBase64(input string) ([]byte, error) {
 	return r.Decrypt(base64Decoded)
 }
 
+// NewRsaEncrypter returns a RsaEncrypter with the given key.
 func NewRsaEncrypter(key []byte) (RsaEncrypter, error) {
 	block, _ := pem.Decode(key)
 	if block == nil {