package filer import ( "bytes" "code.google.com/p/weed-fs/go/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 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 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 DirectoryId, fileName string) (fid string, err error) { if fid, err = fl.FindFile(dirId, fileName); err != nil { return } err = fl.db.Delete(genKey(dirId, fileName), nil) return fid, err } func (fl *FileListInLevelDb) FindFile(dirId DirectoryId, fileName string) (fid string, err error) { data, e := fl.db.Get(genKey(dirId, fileName), nil) if e != nil { return "", e } return string(data), nil } func (fl *FileListInLevelDb) ListFiles(dirId DirectoryId, lastFileName string, limit int) (files []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, FileEntry{Name: fileName, Id: FileId(string(iter.Value()))}) } iter.Release() return }