index_levedb.go

package volume

import (

    "github.com/syndtr/goleveldb/leveldb"

    "encoding/binary"

    "path/filepath"

    "strconv"

)

//文件索引结构体

type LevelDBIndex struct {

    path string

    db   *leveldb.DB

}

//创建leveldb索引

func NewLevelDBIndex(dir string, vid uint64) (index *LevelDBIndex, err error) {

    path := filepath.Join(dir, strconv.FormatUint(vid, 10) + ".index")

    index = new(LevelDBIndex)

    index.path = path

    index.db, err = leveldb.OpenFile(path, nil)

    return index, err

}

//实现index接口

//文件是否存在  物理存在

func (l *LevelDBIndex)Has(fid uint64) bool {

    key := make([]byte, 8)

    binary.BigEndian.PutUint64(key, fid)

    _, err := l.db.Get(key, nil)

    return err == nil

}

//获取文件

func (l *LevelDBIndex)Get(fid uint64) (*FileInfo, error) {

    key := make([]byte, 8)

    binary.BigEndian.PutUint64(key, fid)

    data, err := l.db.Get(key, nil)

    if err != nil {

        return nil, err

    }

    fi := new(FileInfo)

    return fi, fi.UnMarshalBinary(data)

}

//存储文件

func (l *LevelDBIndex)Set(fi *FileInfo) error {

    data := fi.MarshalBinary()

    return l.db.Put(data[:8], data, nil)

}

//删除文件

func (l *LevelDBIndex)Delete(fid uint64) error {

    key := make([]byte, 8)

    binary.BigEndian.PutUint64(key, fid)

    return l.db.Delete(key, nil)

}

//关闭资源

func (l *LevelDBIndex)Close() error {

    return l.db.Close()

}