minio/fs-v1-metadata.go
Harshavardhana b2293c2bf4 XL: Rename, cleanup and add more comments. (#1769)
- xl-v1-bucket.go - removes a whole bunch of code.
- {xl-v1,fs-v1}-metadata.go - add a lot of comments and rename functions
   appropriately.
2016-05-28 15:15:53 -07:00

126 lines
2.9 KiB
Go

package main
import (
"bytes"
"encoding/json"
"io"
"path"
"sort"
)
const (
fsMetaJSONFile = "fs.json"
)
// 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"`
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
}
// ObjectPartIndex - returns the index of matching object part number.
func (m fsMetaV1) ObjectPartIndex(partNumber int) (partIndex int) {
for i, part := range m.Parts {
if partNumber == part.Number {
partIndex = i
return partIndex
}
}
return -1
}
// AddObjectPart - add a new object part in order.
func (m *fsMetaV1) AddObjectPart(partNumber int, partName string, partETag string, partSize int64) {
partInfo := objectPartInfo{
Number: partNumber,
Name: partName,
ETag: partETag,
Size: partSize,
}
// Update part info if it already exists.
for i, part := range m.Parts {
if partNumber == part.Number {
m.Parts[i] = partInfo
return
}
}
// Proceed to include new part info.
m.Parts = append(m.Parts, partInfo)
// Parts in fsMeta should be in sorted order by part number.
sort.Sort(byPartNumber(m.Parts))
}
// readFSMetadata - returns the object metadata `fs.json` content.
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
}
// newFSMetaV1 - initializes new fsMetaV1.
func newFSMetaV1() (fsMeta fsMetaV1) {
fsMeta = fsMetaV1{}
fsMeta.Version = "1"
fsMeta.Format = "fs"
fsMeta.Minio.Release = minioReleaseTag
return fsMeta
}
// writeFSMetadata - writes `fs.json` metadata.
func (fs fsObjects) writeFSMetadata(bucket, prefix string, fsMeta fsMetaV1) error {
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
}