Implement signed data calculating function from SignedDataReader

service/errors.go

@@ -43,3 +43,7 @@ const ErrNilDataWithTokenSignAccumulator = internal.Error("signed data with toke
 // ErrNilSignatureKeySourceWithToken is returned by functions that expect
 // a non-nil SignatureKeySourceWithToken, but received nil.
 const ErrNilSignatureKeySourceWithToken = internal.Error("key-signature source with token is nil")
+
+// ErrNilSignedDataReader is returned by functions that expect
+// a non-nil SignedDataReader, but received nil.
+const ErrNilSignedDataReader = internal.Error("signed data reader is nil")

service/token.go

@@ -123,11 +123,7 @@ func (m *Token) AddSignKey(sig []byte, _ *ecdsa.PublicKey) {
 
 // SignedData returns token information in a binary representation.
 func (m *Token) SignedData() ([]byte, error) {
-	data := make([]byte, m.SignedDataSize())
-
-	copyTokenSignedData(data, m)
-
-	return data, nil
+	return SignedDataFromReader(m)
 }
 
 // ReadSignedData copies a binary representation of the token information to passed buffer.

service/utils.go

@@ -0,0 +1,18 @@
+package service
+
+// SignedDataFromReader allocates buffer and reads bytes from passed reader to it.
+//
+// If passed SignedDataReader is nil, ErrNilSignedDataReader returns.
+func SignedDataFromReader(r SignedDataReader) ([]byte, error) {
+	if r == nil {
+		return nil, ErrNilSignedDataReader
+	}
+
+	data := make([]byte, r.SignedDataSize())
+
+	if _, err := r.ReadSignedData(data); err != nil {
+		return nil, err
+	}
+
+	return data, nil
+}

service/utils_test.go

@@ -0,0 +1,34 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/pkg/errors"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSignedDataFromReader(t *testing.T) {
+	// nil SignedDataReader
+	_, err := SignedDataFromReader(nil)
+	require.EqualError(t, err, ErrNilSignedDataReader.Error())
+
+	rdr := &testSignedDataReader{
+		testSignedDataSrc: new(testSignedDataSrc),
+	}
+
+	// make reader to return an error
+	rdr.err = errors.New("test error")
+
+	_, err = SignedDataFromReader(rdr)
+	require.EqualError(t, err, rdr.err.Error())
+
+	// remove the error
+	rdr.err = nil
+
+	// fill the data
+	rdr.data = testData(t, 10)
+
+	res, err := SignedDataFromReader(rdr)
+	require.NoError(t, err)
+	require.Equal(t, rdr.data, res)
+}