minio/pkg/storage/donut/v1/donut.go
2015-02-20 23:07:43 -08:00

115 lines
3.5 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 (
"encoding/binary"
"io"
)
/*
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 DonutFormat struct {
BlockStart uint32 // Magic="MINI"=1229867341
VersionMajor uint16
VersionMinor uint16
VersionPatch uint16
VersionReserved uint16
Reserved uint64
GobHeaderLen uint32
GobHeader GobHeader
BlockData uint32 // Magic="DATA"=1096040772
Data io.Reader
BlockLen uint64
BlockEnd uint32
}
type DonutFooter struct {
BlockLen uint64
BlockEnd uint32 // Magic="INIM"=1229867341
}
type Donut struct {
file io.Writer
// mutex
}
type GobHeader struct{}
func (donut *Donut) Write(gobHeader GobHeader, object io.Reader) error {
// TODO mutex
// Create bytes buffer representing the new object
donutFormat := DonutFormat{
BlockStart: MagicMINI,
VersionMajor: 1,
VersionMinor: 0,
VersionPatch: 0,
VersionReserved: 0,
Reserved: 0,
GobHeaderLen: 0,
GobHeader: gobHeader,
BlockData: MagicDATA,
Data: object,
BlockLen: 0,
BlockEnd: MagicINIM,
}
if err := donut.WriteFormat(donut.file, donutFormat); err != nil {
return err
}
return nil
}
func (donut *Donut) WriteFormat(target io.Writer, donutFormat DonutFormat) error {
err := binary.Write(target, binary.LittleEndian, donutFormat.BlockStart)
err = binary.Write(target, binary.LittleEndian, donutFormat.VersionMajor)
err = binary.Write(target, binary.LittleEndian, donutFormat.VersionMinor)
err = binary.Write(target, binary.LittleEndian, donutFormat.VersionPatch)
err = binary.Write(target, binary.LittleEndian, donutFormat.VersionReserved)
err = binary.Write(target, binary.LittleEndian, donutFormat.Reserved)
err = binary.Write(target, binary.LittleEndian, donutFormat.GobHeaderLen)
err = binary.Write(target, binary.LittleEndian, donutFormat.GobHeader)
err = binary.Write(target, binary.LittleEndian, donutFormat.BlockData)
err = binary.Write(target, binary.LittleEndian, donutFormat.Data)
err = binary.Write(target, binary.LittleEndian, donutFormat.BlockLen)
err = binary.Write(target, binary.LittleEndian, donutFormat.BlockEnd)
return err
}