github.com/hechain20/hechain@v0.0.0-20220316014945-b544036ba106/core/ledger/kvledger/txmgmt/statedb/statecouchdb/redolog.go (about) 1 /* 2 Copyright hechain. All Rights Reserved. 3 4 SPDX-License-Identifier: Apache-2.0 5 */ 6 7 package statecouchdb 8 9 import ( 10 "bytes" 11 "encoding/gob" 12 13 "github.com/hechain20/hechain/common/ledger/util/leveldbhelper" 14 "github.com/hechain20/hechain/core/ledger/internal/version" 15 "github.com/hechain20/hechain/core/ledger/kvledger/txmgmt/statedb" 16 ) 17 18 var redoLogKey = []byte{byte(0)} 19 20 type redoLoggerProvider struct { 21 leveldbProvider *leveldbhelper.Provider 22 } 23 24 type redoLogger struct { 25 dbHandle *leveldbhelper.DBHandle 26 } 27 28 type redoRecord struct { 29 UpdateBatch *statedb.UpdateBatch 30 Version *version.Height 31 } 32 33 func newRedoLoggerProvider(dirPath string) (*redoLoggerProvider, error) { 34 provider, err := leveldbhelper.NewProvider(&leveldbhelper.Conf{DBPath: dirPath}) 35 if err != nil { 36 return nil, err 37 } 38 return &redoLoggerProvider{leveldbProvider: provider}, nil 39 } 40 41 func (p *redoLoggerProvider) newRedoLogger(dbName string) *redoLogger { 42 return &redoLogger{ 43 dbHandle: p.leveldbProvider.GetDBHandle(dbName), 44 } 45 } 46 47 func (p *redoLoggerProvider) close() { 48 p.leveldbProvider.Close() 49 } 50 51 func (l *redoLogger) persist(r *redoRecord) error { 52 v, err := encodeRedologVal(r) 53 if err != nil { 54 return err 55 } 56 return l.dbHandle.Put(redoLogKey, v, true) 57 } 58 59 func (l *redoLogger) load() (*redoRecord, error) { 60 v, err := l.dbHandle.Get(redoLogKey) 61 if err != nil || v == nil { 62 return nil, err 63 } 64 return decodeRedologVal(v) 65 } 66 67 func encodeRedologVal(r *redoRecord) ([]byte, error) { 68 buf := bytes.NewBuffer(nil) 69 encoder := gob.NewEncoder(buf) 70 if err := encoder.Encode(r); err != nil { 71 return nil, err 72 } 73 return buf.Bytes(), nil 74 } 75 76 func decodeRedologVal(b []byte) (*redoRecord, error) { 77 decoder := gob.NewDecoder(bytes.NewBuffer(b)) 78 var r *redoRecord 79 if err := decoder.Decode(&r); err != nil { 80 return nil, err 81 } 82 return r, nil 83 }