all: remove usage of constant errors

attribute_errorcode.go

@@ -1,5 +1,7 @@
 package stun
 
+import "errors"
+
 // ErrorCodeAttribute represents ERROR-CODE attribute.
 type ErrorCodeAttribute struct {
 	Code   ErrorCode
@@ -15,21 +17,26 @@ const (
 	errorCodeModulo      = 100
 )
 
+// ErrReasonLengthTooBig means that len(Reason) > 763 bytes.
+var ErrReasonLengthTooBig = errors.New("reason for ERROR-CODE is too big")
+
 // AddTo adds ERROR-CODE to m.
 func (c *ErrorCodeAttribute) AddTo(m *Message) error {
-	value := make([]byte,
-		errorCodeReasonStart, errorCodeReasonMaxB,
-	)
+	value := make([]byte, 0, errorCodeReasonMaxB)
+	if len(c.Reason) > errorCodeReasonMaxB {
+		return ErrReasonLengthTooBig
+	}
+	value = value[:errorCodeReasonStart+len(c.Reason)]
 	number := byte(c.Code % errorCodeModulo) // error code modulo 100
 	class := byte(c.Code / errorCodeModulo)  // hundred digit
 	value[errorCodeClassByte] = class
 	value[errorCodeNumberByte] = number
-	value = append(value, c.Reason...)
+	copy(value[errorCodeReasonStart:], c.Reason)
 	m.Add(AttrErrorCode, value)
 	return nil
 }
 
-// GetFrom decodes ERROR-CODE from m.
+// GetFrom decodes ERROR-CODE from m. Reason is valid until m.Raw is valid.
 func (c *ErrorCodeAttribute) GetFrom(m *Message) error {
 	v, err := m.Get(AttrErrorCode)
 	if err != nil {
@@ -39,10 +46,9 @@ func (c *ErrorCodeAttribute) GetFrom(m *Message) error {
 		class  = uint16(v[errorCodeClassByte])
 		number = uint16(v[errorCodeNumberByte])
 		code   = int(class*errorCodeModulo + number)
-		reason = v[errorCodeReasonStart:]
 	)
 	c.Code = ErrorCode(code)
-	c.Reason = reason
+	c.Reason = v[errorCodeReasonStart:]
 	return nil
 }
 
@@ -51,7 +57,7 @@ type ErrorCode int
 
 // ErrNoDefaultReason means that default reason for provided error code
 // is not defined in RFC.
-const ErrNoDefaultReason Error = "No default reason for ErrorCode"
+var ErrNoDefaultReason = errors.New("No default reason for ErrorCode")
 
 // AddTo adds ERROR-CODE with default reason to m. If there
 // is no default reason, returns ErrNoDefaultReason.

attribute_xoraddr.go

@@ -1,6 +1,7 @@
 package stun
 
 import (
+	"errors"
 	"fmt"
 	"net"
 )
@@ -31,7 +32,7 @@ func isZeros(p net.IP) bool {
 }
 
 // ErrBadIPLength means that len(IP) is not net.{IPv6len,IPv4len}.
-const ErrBadIPLength Error = "invalid length if IP value"
+var ErrBadIPLength = errors.New("invalid length if IP value")
 
 // AddTo adds XOR-MAPPED-ADDRESS to m. Can return ErrBadIPLength
 // if len(a.IP) is invalid.

attributes.go

@@ -1,6 +1,7 @@
 package stun
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 )
@@ -118,8 +119,6 @@ func (t AttrType) String() string {
 // don't understand, but cannot successfully process a message if it
 // contains comprehension-required attributes that are not
 // understood.
-//
-// TODO(ar): Decide to use pointer or non-pointer RawAttribute.
 type RawAttribute struct {
 	Type   AttrType
 	Length uint16 // ignored while encoding
@@ -157,7 +156,7 @@ func (a RawAttribute) String() string {
 
 // ErrAttributeNotFound means that attribute with provided attribute
 // type does not exist in message.
-const ErrAttributeNotFound Error = "Attribute not found"
+var ErrAttributeNotFound = errors.New("Attribute not found")
 
 // Get returns byte slice that represents attribute value,
 // if there is no attribute with such type,

attributes_test.go

@@ -212,6 +212,19 @@ func BenchmarkErrorCodeAttribute_AddTo(b *testing.B) {
 	}
 }
 
+func BenchmarkErrorCodeAttribute_GetFrom(b *testing.B) {
+	m := New()
+	b.ReportAllocs()
+	a := &ErrorCodeAttribute{
+		Code:   404,
+		Reason: []byte("not found!"),
+	}
+	a.AddTo(m)
+	for i := 0; i < b.N; i++ {
+		a.GetFrom(m)
+	}
+}
+
 func TestMessage_AddErrorCode(t *testing.T) {
 	m := New()
 	transactionID, err := base64.StdEncoding.DecodeString("jxhBARZwX+rsC6er")
@@ -243,3 +256,11 @@ func TestMessage_AddErrorCode(t *testing.T) {
 		t.Error("bad reason", string(errCodeAttr.Reason))
 	}
 }
+
+func BenchmarkMessage_GetNotFound(b *testing.B) {
+	m := New()
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		m.Get(AttrRealm)
+	}
+}

errors.go

@@ -1,14 +1,5 @@
 package stun
 
-// Error is error type for constant errors in stun package.
-//
-// See http://dave.cheney.net/2016/04/07/constant-errors for more info.
-type Error string
-
-func (e Error) Error() string {
-	return string(e)
-}
-
 // DecodeErr records an error and place when it is occurred.
 type DecodeErr struct {
 	Place   DecodeErrPlace

errors_test.go

@@ -1,25 +0,0 @@
-package stun
-
-import "testing"
-
-func TestDecodeErr(t *testing.T) {
-	err := newDecodeErr("parent", "children", "message")
-	if !err.IsPlace(DecodeErrPlace{Parent: "parent", Children: "children"}) {
-		t.Error("isPlace test failed")
-	}
-	if !err.IsPlaceParent("parent") {
-		t.Error("parent test failed")
-	}
-	if !err.IsPlaceChildren("children") {
-		t.Error("children test failed")
-	}
-	if err.Error() != "BadFormat for parent/children: message" {
-		t.Error("bad Error string")
-	}
-}
-
-func TestError_Error(t *testing.T) {
-	if Error("error").Error() != "error" {
-		t.Error("bad Error string")
-	}
-}

message.go

@@ -24,6 +24,7 @@ import (
 	"crypto/rand"
 	"encoding/base64"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"strconv"
@@ -261,11 +262,9 @@ func (m *Message) ReadFrom(r io.Reader) (int64, error) {
 	return int64(n), m.Decode()
 }
 
-const (
 // ErrUnexpectedHeaderEOF means that there were not enough bytes in
 // m.Raw to read header.
-	ErrUnexpectedHeaderEOF Error = "unexpected EOF: not enough bytes to read header"
-)
+var ErrUnexpectedHeaderEOF = errors.New("unexpected EOF: not enough bytes to read header")
 
 // Decode decodes m.Raw into m.
 func (m *Message) Decode() error {

stun_test.go

@@ -15,19 +15,12 @@ import (
 	"strconv"
 	"strings"
 	"testing"
-
-	"github.com/pkg/errors"
-	log "github.com/sirupsen/logrus"
 )
 
 func bUint16(v uint16) string {
 	return fmt.Sprintf("0b%016s", strconv.FormatUint(uint64(v), 2))
 }
 
-func init() {
-	log.SetLevel(log.DebugLevel)
-}
-
 func (m *Message) reader() *bytes.Reader {
 	return bytes.NewReader(m.Raw)
 }
@@ -185,7 +178,7 @@ func TestMessage_AttrLengthLessThanHeader(t *testing.T) {
 	mDecoded := New()
 	binary.BigEndian.PutUint16(m.Raw[2:4], 2) // rewrite to bad length
 	_, err := mDecoded.ReadFrom(bytes.NewReader(m.Raw[:20+2]))
-	switch e := errors.Cause(err).(type) {
+	switch e := err.(type) {
 	case *DecodeErr:
 		if !e.IsPlace(DecodeErrPlace{"attribute", "header"}) {
 			t.Error(e, "bad place")
@@ -213,7 +206,7 @@ func TestMessage_AttrSizeLessThanLength(t *testing.T) {
 	bin.PutUint16(m.Raw[2:4], 5) // rewrite to bad length
 	mDecoded := New()
 	_, err := mDecoded.ReadFrom(bytes.NewReader(m.Raw[:20+5]))
-	switch e := errors.Cause(err).(type) {
+	switch e := err.(type) {
 	case *DecodeErr:
 		if !e.IsPlace(DecodeErrPlace{"attribute", "value"}) {
 			t.Error(e, "bad place")
@@ -232,7 +225,7 @@ func (r unexpectedEOFReader) Read(b []byte) (int, error) {
 func TestMessage_ReadFromError(t *testing.T) {
 	mDecoded := New()
 	_, err := mDecoded.ReadFrom(unexpectedEOFReader{})
-	if errors.Cause(err) != io.ErrUnexpectedEOF {
+	if err != io.ErrUnexpectedEOF {
 		t.Error(err, "should be", io.ErrUnexpectedEOF)
 	}
 }