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