XL/FS: Rewrite in new format.

fs-v1-metadata.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"path"
+	"sort"
+)
+
+// A fsMetaV1 represents a metadata header mapping keys to sets of values.
+type fsMetaV1 struct {
+	Version string `json:"version"`
+	Format  string `json:"format"`
+	Minio   struct {
+		Release string `json:"release"`
+	} `json:"minio"`
+	Checksum struct {
+		Enable bool `json:"enable"`
+	} `json:"checksum"`
+	Parts []objectPartInfo `json:"parts,omitempty"`
+}
+
+// ReadFrom - read from implements io.ReaderFrom interface for
+// unmarshalling fsMetaV1.
+func (m *fsMetaV1) ReadFrom(reader io.Reader) (n int64, err error) {
+	var buffer bytes.Buffer
+	n, err = buffer.ReadFrom(reader)
+	if err != nil {
+		return 0, err
+	}
+	err = json.Unmarshal(buffer.Bytes(), m)
+	return n, err
+}
+
+// WriteTo - write to implements io.WriterTo interface for marshalling fsMetaV1.
+func (m fsMetaV1) WriteTo(writer io.Writer) (n int64, err error) {
+	metadataBytes, err := json.Marshal(m)
+	if err != nil {
+		return 0, err
+	}
+	p, err := writer.Write(metadataBytes)
+	return int64(p), err
+}
+
+// SearchObjectPart - search object part name and etag.
+func (m fsMetaV1) SearchObjectPart(name string, etag string) int {
+	for i, part := range m.Parts {
+		if name == part.Name && etag == part.ETag {
+			return i
+		}
+	}
+	return -1
+}
+
+// AddObjectPart - add a new object part in order.
+func (m *fsMetaV1) AddObjectPart(name string, etag string, size int64) {
+	m.Parts = append(m.Parts, objectPartInfo{
+		Name: name,
+		ETag: etag,
+		Size: size,
+	})
+	sort.Sort(byPartName(m.Parts))
+}
+
+const (
+	fsMetaJSONFile = "fs.json"
+)
+
+// readFSMetadata - read `fs.json`.
+func (fs fsObjects) readFSMetadata(bucket, object string) (fsMeta fsMetaV1, err error) {
+	r, err := fs.storage.ReadFile(bucket, path.Join(object, fsMetaJSONFile), int64(0))
+	if err != nil {
+		return fsMetaV1{}, err
+	}
+	defer r.Close()
+	_, err = fsMeta.ReadFrom(r)
+	if err != nil {
+		return fsMetaV1{}, err
+	}
+	return fsMeta, nil
+}
+
+// writeFSMetadata - write `fs.json`.
+func (fs fsObjects) writeFSMetadata(bucket, prefix string, fsMeta fsMetaV1) error {
+	// Initialize metadata map, save all erasure related metadata.
+	fsMeta.Minio.Release = minioReleaseTag
+	w, err := fs.storage.CreateFile(bucket, path.Join(prefix, fsMetaJSONFile))
+	if err != nil {
+		return err
+	}
+	_, err = fsMeta.WriteTo(w)
+	if err != nil {
+		if mErr := safeCloseAndRemove(w); mErr != nil {
+			return mErr
+		}
+		return err
+	}
+	if err = w.Close(); err != nil {
+		if mErr := safeCloseAndRemove(w); mErr != nil {
+			return mErr
+		}
+		return err
+	}
+	return nil
+}