Adding scaffolding for writing donut

pkg/storage/donut/donut.go

@@ -0,0 +1,78 @@
+/*
+ * Mini Object Storage, (C) 2015 Minio, Inc.
+ *
+ * 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 donut
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/gob"
+	"io"
+)
+
+type Header struct{}
+type Donut struct {
+	file io.Writer
+}
+
+func (donut Donut) Write(header Header, object io.Reader) error {
+	var newObjectBuffer bytes.Buffer
+	var headerBuffer bytes.Buffer
+
+	// create gob header
+	headerEncoder := gob.NewEncoder(&headerBuffer)
+	err := headerEncoder.Encode(header)
+	if err != nil {
+		return err
+	}
+
+	// write header length
+	var headerLengthBuffer bytes.Buffer
+	headerLength := headerBuffer.Len()
+	err = binary.Write(&headerLengthBuffer, binary.LittleEndian, headerLength)
+	if err != nil {
+		return err
+	}
+
+	// write header length
+	io.Copy(&newObjectBuffer, &headerLengthBuffer)
+
+	// write header
+	io.Copy(&newObjectBuffer, &headerBuffer)
+
+	// write header marker
+
+	// TODO
+
+	// write data
+	_, err = io.Copy(&newObjectBuffer, object)
+	if err != nil {
+		return err
+	}
+
+	// write footer
+	// TODO
+
+	// write footer marker
+	// TODO
+
+	// write new object
+	_, err = io.Copy(donut.file, &newObjectBuffer)
+	if err != nil {
+		return err
+	}
+	return nil
+}