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