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package embedded_filer
import (
"bytes"
"github.com/chrislusf/seaweedfs/weed/filer"
"github.com/chrislusf/seaweedfs/weed/glog"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/util"
)
/*
The entry in level db has this format:
key: genKey(dirId, fileName)
value: []byte(fid)
And genKey(dirId, fileName) use first 4 bytes to store dirId, and rest for fileName
*/
type FileListInLevelDb struct {
db *leveldb.DB
}
func NewFileListInLevelDb(dir string) (fl *FileListInLevelDb, err error) {
fl = &FileListInLevelDb{}
if fl.db, err = leveldb.OpenFile(dir, nil); err != nil {
return
}
return
}
func genKey(dirId filer.DirectoryId, fileName string) []byte {
ret := make([]byte, 0, 4+len(fileName))
for i := 3; i >= 0; i-- {
ret = append(ret, byte(dirId>>(uint(i)*8)))
}
ret = append(ret, []byte(fileName)...)
return ret
}
func (fl *FileListInLevelDb) CreateFile(dirId filer.DirectoryId, fileName string, fid string) (err error) {
glog.V(4).Infoln("directory", dirId, "fileName", fileName, "fid", fid)
return fl.db.Put(genKey(dirId, fileName), []byte(fid), nil)
}
func (fl *FileListInLevelDb) DeleteFile(dirId filer.DirectoryId, fileName string) (fid string, err error) {
if fid, err = fl.FindFile(dirId, fileName); err != nil {
if err == leveldb.ErrNotFound {
return "", nil
}
return
}
err = fl.db.Delete(genKey(dirId, fileName), nil)
return fid, err
}
func (fl *FileListInLevelDb) FindFile(dirId filer.DirectoryId, fileName string) (fid string, err error) {
data, e := fl.db.Get(genKey(dirId, fileName), nil)
if e == leveldb.ErrNotFound {
return "", filer.ErrNotFound
} else if e != nil {
return "", e
}
return string(data), nil
}
func (fl *FileListInLevelDb) ListFiles(dirId filer.DirectoryId, lastFileName string, limit int) (files []filer.FileEntry) {
glog.V(4).Infoln("directory", dirId, "lastFileName", lastFileName, "limit", limit)
dirKey := genKey(dirId, "")
iter := fl.db.NewIterator(&util.Range{Start: genKey(dirId, lastFileName)}, nil)
limitCounter := 0
for iter.Next() {
key := iter.Key()
if !bytes.HasPrefix(key, dirKey) {
break
}
fileName := string(key[len(dirKey):])
if fileName == lastFileName {
continue
}
limitCounter++
if limit > 0 {
if limitCounter > limit {
break
}
}
files = append(files, filer.FileEntry{Name: fileName, Id: filer.FileId(string(iter.Value()))})
}
iter.Release()
return
}
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