Merge pull request #19 from saharshagrawal/endorsements

Added support for endorsement operation.

contents_tag.go

@@ -12,4 +12,6 @@ const (
 	ContentsTagOrigination ContentsTag = 109
 	// ContentsTagDelegation is the tag for delegations
 	ContentsTagDelegation ContentsTag = 110
+	// ContentsTagEndorsement is the tag for endorsements
+	ContentsTagEndorsement ContentsTag = 0
 )

endorsement.go

@@ -0,0 +1,80 @@
+package tezosprotocol
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+
+	"golang.org/x/xerrors"
+)
+
+// Endorsement models the tezos endorsement operation type
+type Endorsement struct {
+	Level int32
+}
+
+func (e *Endorsement) String() string {
+	return fmt.Sprintf("%#v", e)
+}
+
+// GetTag implements OperationContents
+func (e *Endorsement) GetTag() ContentsTag {
+	return ContentsTagEndorsement
+}
+
+// MarshalBinary implements encoding.BinaryMarshaler
+func (e *Endorsement) MarshalBinary() ([]byte, error) {
+	buf := bytes.Buffer{}
+
+	// tag
+	buf.WriteByte(byte(e.GetTag()))
+
+	// Level
+	levelBytesBuf := new(bytes.Buffer)
+	err := binary.Write(levelBytesBuf, binary.BigEndian, e.Level)
+	if err != nil {
+		return []byte(""), xerrors.Errorf("%w", err)
+	}
+	_, err = buf.Write(levelBytesBuf.Bytes())
+	if err != nil {
+		return []byte(""), xerrors.Errorf("%w", err)
+	}
+
+	return buf.Bytes(), nil
+}
+
+func readInt32(data []byte) (ret int32, err error) {
+	buf := bytes.NewBuffer(data)
+	err = binary.Read(buf, binary.BigEndian, &ret)
+	return ret, err
+}
+
+// UnmarshalBinary implements encoding.BinaryUnmarshaler
+func (e *Endorsement) UnmarshalBinary(data []byte) (err error) {
+	// cleanly recover from out of bounds exceptions
+	defer func() {
+		if err == nil {
+			if r := recover(); r != nil {
+				err = catchOutOfRangeExceptions(r)
+			}
+		}
+	}()
+
+	dataPtr := data
+
+	// tag
+	tag := ContentsTag(dataPtr[0])
+	if tag != ContentsTagEndorsement {
+		return xerrors.Errorf("invalid tag for endorsement. Expected %d, saw %d", ContentsTagEndorsement, tag)
+	}
+	dataPtr = dataPtr[1:]
+
+	// Level
+	level, err := readInt32(dataPtr)
+	if err != nil {
+		return xerrors.Errorf("failed to unmarshal level: %w", err)
+	}
+	e.Level = level
+
+	return nil
+}

endorsement_test.go

@@ -0,0 +1,30 @@
+package tezosprotocol_test
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/anchorageoss/tezosprotocol/v2"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEncodeEndorsement(t *testing.T) {
+	require := require.New(t)
+	origination := &tezosprotocol.Endorsement{
+		Level: 999,
+	}
+	encodedBytes, err := origination.MarshalBinary()
+	require.NoError(err)
+	encoded := hex.EncodeToString(encodedBytes)
+	expected := "00000003e7"
+	require.Equal(expected, encoded)
+}
+
+func TestDecodeEndorsement(t *testing.T) {
+	require := require.New(t)
+	encoded, err := hex.DecodeString("00000003e7")
+	require.NoError(err)
+	endorsement := tezosprotocol.Endorsement{}
+	require.NoError(endorsement.UnmarshalBinary(encoded))
+	require.Equal(int32(999), endorsement.Level)
+}