add a gob-encoding Serializer implementation for tests

serializer.go

@@ -0,0 +1,60 @@
+// Copyright 2017 Pilosa Corp.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pilosa
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+
+	"github.com/pkg/errors"
+)
+
+// GobSerializer represents a Serializer that uses gob encoding. This is only
+// used in tests; there's really no reason to use this instead of the proto
+// serializer except that, as it's currently implemented, the proto serializer
+// can't be used in internal tests (i.e test in the pilosa package) because the
+// proto package imports the pilosa package, so it would result in circular
+// imports. We really need all the pilosa types to be in a sub-package of
+// pilosa, so that both proto and pilosa can import them without resulting in
+// circular imports.
+var GobSerializer Serializer = &gobSerializer{}
+
+type gobSerializer struct{}
+
+// Marshal is a gob-encoded implementation of the Serializer Marshal method.
+func (s *gobSerializer) Marshal(msg Message) ([]byte, error) {
+	var buf bytes.Buffer
+	enc := gob.NewEncoder(&buf)
+	if err := enc.Encode(msg); err != nil {
+		return nil, errors.Wrap(err, "gob encoding message")
+	}
+	return buf.Bytes(), nil
+}
+
+// Unmarshal is a gob-encoded implementation of the Serializer Unmarshal method.
+func (s *gobSerializer) Unmarshal(b []byte, m Message) error {
+	switch mt := m.(type) {
+	case *CreateIndexMessage, *CreateFieldMessage:
+		dec := gob.NewDecoder(bytes.NewReader(b))
+		err := dec.Decode(mt)
+		if err != nil {
+			return errors.Wrapf(err, "decoding %T", mt)
+		}
+		return nil
+	default:
+		panic(fmt.Sprintf("unhandled Message of type %T: %#v", mt, m))
+	}
+}