minio/pkg/storage/donut/v1/donut.go

145 lines
3.8 KiB
Go

/*
* 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 v1
import (
"bytes"
"encoding/binary"
"io"
"github.com/minio-io/minio/pkg/utils/checksum/crc32c"
"github.com/minio-io/minio/pkg/utils/crypto/sha512"
)
/*
DONUT v1 Spec
**********************
BlockStart [4]byte // Magic="MINI"=1229867341
VersionMajor uint16
VersionMinor uint16
VersionPatch uint16
VersionReserved uint16
Reserved uint64
GobHeaderLen uint32
GobHeader io.Reader // matches length
BlockData [4]byte // Magic="DATA"=1096040772
Data io.Reader // matches length
BlockLen uint64 // length to block start
BlockEnd [4]byte // Magic="INIM"=1296649801
*/
var (
MagicMINI = binary.LittleEndian.Uint32([]byte{'M', 'I', 'N', 'I'})
MagicDATA = binary.LittleEndian.Uint32([]byte{'D', 'A', 'T', 'A'})
MagicINIM = binary.LittleEndian.Uint32([]byte{'I', 'N', 'I', 'M'})
)
type DonutFrameHeader struct {
MagicMINI uint32
VersionMajor uint16
VersionMinor uint16
VersionPatch uint16
VersionReserved uint16
Reserved uint64
DataLength uint64
}
type Crc32c uint32
type Sha512 [sha512.Size]byte
type DonutFrameFooter struct {
DataSha512 Sha512
OffsetToMINI uint64
MagicINIM uint32
}
type Data bytes.Buffer
func Write(target io.Writer, reader io.Reader, length uint64) error {
// write header
header := DonutFrameHeader{
MagicMINI: MagicMINI,
VersionMajor: 1,
VersionMinor: 0,
VersionPatch: 0,
VersionReserved: 0,
Reserved: 0,
DataLength: length,
}
var headerBytes bytes.Buffer
binary.Write(&headerBytes, binary.LittleEndian, header)
headerCrc := crc32c.Sum32(headerBytes.Bytes())
binary.Write(&headerBytes, binary.LittleEndian, headerCrc)
binary.Write(&headerBytes, binary.LittleEndian, MagicDATA)
// write header
headerLen, err := io.Copy(target, &headerBytes)
if err != nil {
return err
}
// write DATA
// create sha512 tee
sumReader, sumWriter := io.Pipe()
defer sumWriter.Close()
checksumChannel := make(chan checksumValue)
go generateChecksum(sumReader, checksumChannel)
teeReader := io.TeeReader(reader, sumWriter)
_, err = io.Copy(target, teeReader)
if err != nil {
return err
}
sumWriter.Close()
dataChecksum := <-checksumChannel
if dataChecksum.err != nil {
return dataChecksum.err
}
// generate footer
frameFooter := DonutFrameFooter{
DataSha512: dataChecksum.checksum,
OffsetToMINI: length + uint64(headerLen) + uint64(80), /*footer size*/
MagicINIM: MagicINIM,
}
var frameFooterBytes bytes.Buffer
binary.Write(&frameFooterBytes, binary.LittleEndian, frameFooter)
// write footer crc
footerChecksum := crc32c.Sum32(frameFooterBytes.Bytes())
if err := binary.Write(target, binary.LittleEndian, footerChecksum); err != nil {
return err
}
// write write footer
_, err = io.Copy(target, &frameFooterBytes)
if err != nil {
return err
}
return nil
}
type checksumValue struct {
checksum Sha512
err error
}
func generateChecksum(reader io.Reader, c chan<- checksumValue) {
checksum, err := sha512.SumStream(reader)
result := checksumValue{
checksum: checksum,
err: err,
}
c <- result
}