1 files changed, 112 insertions, 0 deletions
diff --git a/weed/storage/needle_map/memdb.go b/weed/storage/needle_map/memdb.go
new file mode 100644
index 000000000..6aba6adeb
--- /dev/null
+++ b/weed/storage/needle_map/memdb.go
@@ -0,0 +1,112 @@
+package needle_map
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage/idx"
+	. "github.com/chrislusf/seaweedfs/weed/storage/types"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+//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 uint32) 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 := util.BytesToUint32(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 (cm *MemDb) AscendingVisit(visit func(NeedleValue) error) (ret error) {
+	iter := cm.db.NewIterator(nil, nil)
+	for iter.Next() {
+		key := BytesToNeedleId(iter.Key())
+		data := iter.Value()
+		offset := BytesToOffset(data[0:OffsetSize])
+		size := util.BytesToUint32(data[OffsetSize : OffsetSize+SizeSize])
+
+		needle := NeedleValue{Key: key, Offset: offset, Size: size}
+		ret = visit(needle)
+		if 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 idxFile.Close()
+
+	return cm.AscendingVisit(func(value NeedleValue) error {
+		_, 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 idx.WalkIndexFile(idxFile, func(key NeedleId, offset Offset, size uint32) error {
+		if offset.IsZero() || size == TombstoneFileSize {
+			return nil
+		}
+		return cm.Set(key, offset, size)
+	})
+
+}