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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/util/log"
"github.com/chrislusf/seaweedfs/weed/storage/idx"
. "github.com/chrislusf/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 {
log.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 (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 := BytesToSize(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 {
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 idx.WalkIndexFile(idxFile, 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()
}
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