prepare to remove constructor of AuthenticationReader

common/crypto/auth.go

@@ -87,8 +87,10 @@ type AuthenticationReader struct {
 	sizeParser   ChunkSizeDecoder
 	transferType protocol.TransferType
 	padding      PaddingLengthGenerator
-	size         int32
-	paddingLen   int32
+	size         uint16
+	paddingLen   uint16
+	hasSize      bool
+	done         bool
 }
 
 func NewAuthenticationReader(auth Authenticator, sizeParser ChunkSizeDecoder, reader io.Reader, transferType protocol.TransferType, paddingLen PaddingLengthGenerator) *AuthenticationReader {
@@ -98,26 +100,24 @@ func NewAuthenticationReader(auth Authenticator, sizeParser ChunkSizeDecoder, re
 		sizeParser:   sizeParser,
 		transferType: transferType,
 		padding:      paddingLen,
-		size:         -1,
 	}
 }
 
-func (r *AuthenticationReader) readSize() (int32, int32, error) {
-	if r.size != -1 {
-		s := r.size
-		r.size = -1
-		return s, r.paddingLen, nil
+func (r *AuthenticationReader) readSize() (uint16, uint16, error) {
+	if r.hasSize {
+		r.hasSize = false
+		return r.size, r.paddingLen, nil
 	}
 	sizeBytes := make([]byte, r.sizeParser.SizeBytes())
 	if _, err := io.ReadFull(r.reader, sizeBytes); err != nil {
 		return 0, 0, err
 	}
-	var padding int32
+	var padding uint16
 	if r.padding != nil {
-		padding = int32(r.padding.NextPaddingLen())
+		padding = r.padding.NextPaddingLen()
 	}
 	size, err := r.sizeParser.Decode(sizeBytes)
-	return int32(size), padding, err
+	return size, padding, err
 }
 
 var errSoft = newError("waiting for more data")
@@ -127,31 +127,36 @@ func (r *AuthenticationReader) readInternal(soft bool) (*buf.Buffer, error) {
 		return nil, errSoft
 	}
 
+	if r.done {
+		return nil, io.EOF
+	}
+
 	size, padding, err := r.readSize()
 	if err != nil {
 		return nil, err
 	}
 
-	if size == -2 || size == int32(r.auth.Overhead())+padding {
-		r.size = -2
+	if size == uint16(r.auth.Overhead())+padding {
+		r.done = true
 		return nil, io.EOF
 	}
 
-	if soft && size > r.reader.BufferedBytes() {
+	if soft && int32(size) > r.reader.BufferedBytes() {
 		r.size = size
 		r.paddingLen = padding
+		r.hasSize = true
 		return nil, errSoft
 	}
 
-	b := buf.NewSize(size)
-	if err := b.Reset(buf.ReadFullFrom(r.reader, size)); err != nil {
+	b := buf.NewSize(int32(size))
+	if err := b.Reset(buf.ReadFullFrom(r.reader, int32(size))); err != nil {
 		b.Release()
 		return nil, err
 	}
 
 	size -= padding
 
-	rb, err := r.auth.Open(b.BytesTo(0), b.BytesTo(size))
+	rb, err := r.auth.Open(b.BytesTo(0), b.BytesTo(int32(size)))
 	if err != nil {
 		b.Release()
 		return nil, err