Renaming donut packages to match layout

pkg/storage/donut/erasure/erasure_v1/erasure.go

@@ -0,0 +1,101 @@
+/*
+ * 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 erasure_v1
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/gob"
+	"fmt"
+	"io"
+)
+
+type Metadata map[string]string
+
+type DataHeader struct {
+	Key           string
+	Part          uint8
+	Metadata      Metadata
+	EncoderParams EncoderParams
+}
+
+type EncoderTechnique int
+
+const (
+	Vandermonde EncoderTechnique = iota
+	Cauchy
+)
+
+type EncoderParams struct {
+	Length    uint32
+	K         uint8
+	M         uint8
+	Technique EncoderTechnique
+}
+
+// populate new header
+func NewHeader(key string, part uint8, metadata Metadata, encoderParams EncoderParams) DataHeader {
+	header := DataHeader{}
+	header.Key = key
+	header.Part = part
+	header.Metadata = metadata
+	header.EncoderParams = EncoderParams{
+		Length:    encoderParams.Length,
+		K:         encoderParams.K,
+		M:         encoderParams.M,
+		Technique: encoderParams.Technique,
+	}
+	return header
+}
+
+// validate populated header
+func ValidateHeader(header DataHeader) bool {
+	if header.Key == "" || header.Part < 0 || len(header.Metadata) < 2 {
+		return false
+	}
+
+	if header.EncoderParams.Length < 0 || header.EncoderParams.Technique > 1 {
+		return false
+	}
+
+	return true
+}
+
+// Write data, returns error upon any failure
+func WriteData(target io.Writer, header DataHeader, data io.Reader) error {
+	if !ValidateHeader(header) {
+		return fmt.Errorf("Invalid header")
+	}
+
+	var headerBuffer bytes.Buffer
+	// encode header
+	encoder := gob.NewEncoder(&headerBuffer)
+	encoder.Encode(header)
+
+	// write version
+	binary.Write(target, binary.LittleEndian, uint32(1))
+
+	// write encoded header
+	if _, err := io.Copy(target, &headerBuffer); err != nil {
+		return err
+	}
+	// write data
+	if _, err := io.Copy(target, data); err != nil {
+		return err
+	}
+	return nil
+}

pkg/storage/donut/erasure/erasure_v1/erasure_test.go

@@ -0,0 +1,71 @@
+/*
+ * 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 erasure_v1
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/gob"
+	"io"
+	"testing"
+
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type MySuite struct{}
+
+var _ = Suite(&MySuite{})
+
+func (s *MySuite) TestSingleWrite(c *C) {
+	var testBuffer bytes.Buffer
+	testData := "Hello, World"
+	encoderParams := EncoderParams{
+		Length:    uint32(len(testData)),
+		K:         8,
+		M:         8,
+		Technique: Cauchy,
+	}
+	metadata := make(Metadata)
+	metadata["Content-Type"] = "application/octet-stream"
+	metadata["Content-MD5"] = "testing"
+
+	header := NewHeader("testobj", 1, metadata, encoderParams)
+
+	err := WriteData(&testBuffer, header, bytes.NewBufferString(testData))
+	c.Assert(err, IsNil)
+
+	actualVersion := make([]byte, 4)
+	_, err = testBuffer.Read(actualVersion)
+	c.Assert(err, IsNil)
+	c.Assert(binary.LittleEndian.Uint32(actualVersion), DeepEquals, uint32(1))
+
+	actualHeader := DataHeader{}
+
+	decoder := gob.NewDecoder(&testBuffer)
+	decoder.Decode(&actualHeader)
+
+	c.Assert(actualHeader, DeepEquals, header)
+
+	var actualData bytes.Buffer
+
+	dataLength, err := io.Copy(&actualData, &testBuffer)
+	c.Assert(dataLength, Equals, int64(len(testData)))
+	c.Assert(actualData.Bytes(), DeepEquals, []byte(testData))
+	c.Assert(err, IsNil)
+}