package needle_map import ( "fmt" "io" "os" "github.com/syndtr/goleveldb/leveldb" "github.com/syndtr/goleveldb/leveldb/iterator" "github.com/syndtr/goleveldb/leveldb/opt" "github.com/syndtr/goleveldb/leveldb/storage" "github.com/seaweedfs/seaweedfs/weed/glog" "github.com/seaweedfs/seaweedfs/weed/storage/idx" . "github.com/seaweedfs/seaweedfs/weed/storage/types" ) // This map uses in memory level db type MemDb struct { db *leveldb.DB } func NewMemDb() *MemDb { opts := &opt.Options{} var err error t := &MemDb{} if t.db, err = leveldb.Open(storage.NewMemStorage(), opts); err != nil { glog.V(0).Infof("MemDb fails to open: %v", err) return nil } return t } func (cm *MemDb) Set(key NeedleId, offset Offset, size Size) error { bytes := ToBytes(key, offset, size) if err := cm.db.Put(bytes[0:NeedleIdSize], bytes[NeedleIdSize:NeedleIdSize+OffsetSize+SizeSize], nil); err != nil { return fmt.Errorf("failed to write temp leveldb: %v", err) } return nil } func (cm *MemDb) Delete(key NeedleId) error { bytes := make([]byte, NeedleIdSize) NeedleIdToBytes(bytes, key) return cm.db.Delete(bytes, nil) } func (cm *MemDb) Get(key NeedleId) (*NeedleValue, bool) { bytes := make([]byte, NeedleIdSize) NeedleIdToBytes(bytes[0:NeedleIdSize], key) data, err := cm.db.Get(bytes, nil) if err != nil || len(data) != OffsetSize+SizeSize { return nil, false } offset := BytesToOffset(data[0:OffsetSize]) size := BytesToSize(data[OffsetSize : OffsetSize+SizeSize]) return &NeedleValue{Key: key, Offset: offset, Size: size}, true } // Visit visits all entries or stop if any error when visiting func doVisit(iter iterator.Iterator, visit func(NeedleValue) error) (ret error) { key := BytesToNeedleId(iter.Key()) data := iter.Value() offset := BytesToOffset(data[0:OffsetSize]) size := BytesToSize(data[OffsetSize : OffsetSize+SizeSize]) needle := NeedleValue{Key: key, Offset: offset, Size: size} ret = visit(needle) if ret != nil { return } return nil } func (cm *MemDb) AscendingVisit(visit func(NeedleValue) error) (ret error) { iter := cm.db.NewIterator(nil, nil) if iter.First() { if ret = doVisit(iter, visit); ret != nil { return } } for iter.Next() { if ret = doVisit(iter, visit); ret != nil { return } } iter.Release() ret = iter.Error() return } func (cm *MemDb) DescendingVisit(visit func(NeedleValue) error) (ret error) { iter := cm.db.NewIterator(nil, nil) if iter.Last() { if ret = doVisit(iter, visit); ret != nil { return } } for iter.Prev() { if ret = doVisit(iter, visit); ret != nil { return } } iter.Release() ret = iter.Error() return } func (cm *MemDb) SaveToIdx(idxName string) (ret error) { idxFile, err := os.OpenFile(idxName, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644) if err != nil { return } defer func() { idxFile.Sync() idxFile.Close() }() return cm.AscendingVisit(func(value NeedleValue) error { if value.Offset.IsZero() || value.Size.IsDeleted() { return nil } _, err := idxFile.Write(value.ToBytes()) return err }) } func (cm *MemDb) LoadFromIdx(idxName string) (ret error) { idxFile, err := os.OpenFile(idxName, os.O_RDONLY, 0644) if err != nil { return } defer idxFile.Close() return cm.LoadFromReaderAt(idxFile) } func (cm *MemDb) LoadFromReaderAt(readerAt io.ReaderAt) (ret error) { return idx.WalkIndexFile(readerAt, 0, func(key NeedleId, offset Offset, size Size) error { if offset.IsZero() || size.IsDeleted() { return cm.Delete(key) } return cm.Set(key, offset, size) }) } func (cm *MemDb) Close() { cm.db.Close() }