# Fabric 1.0源代码笔记 之 Tx（Transaction 交易）
## 1、Tx概述
Tx，即Transaction，交易或事务。
Tx代码分布目录结构如下：
* protos/common/common.pb.go，交易的封装即Envelope结构体。也包括Payload、Header、ChannelHeader和SignatureHeader。* protos/utils目录，交易相关部分工具函数，包括txutils.go、proputils.go和commonutils.go。* core/ledger/kvledger/txmgmt目录* rwsetutil目录，读写集相关结构体及方法。* version目录，version.Height结构体及方法。* validator目录，Validator接口及实现。* txmgr目录，TxMgr接口及实现。
## 2、交易的封装Envelope结构体
### 2.1、Envelope结构体
Envelope直译为信封，封装Payload和Signature。
```gotype Envelope struct { //用签名包装Payload，以便对信息做身份验证Payload []byte //Payload序列化Signature []byte //Payload header中指定的创建者签名}//代码在protos/common/common.pb.go```
### 2.2、Payload相关结构体
Payload直译为有效载荷。Payload结构体：
```gotype Payload struct {Header *Header //HeaderData []byte //Transaction序列化}//代码在protos/common/common.pb.go```
Header结构体：
```gotype Header struct {ChannelHeader []byteSignatureHeader []byte}//代码在protos/common/common.pb.go```
ChannelHeader结构体：
```gotype ChannelHeader struct {Type int32Version int32 //消息协议版本Timestamp *google_protobuf.Timestamp //创建消息时的本地时间ChannelId string //消息绑定的ChannelIdTxId string //TxIdEpoch uint64 //纪元Extension []byte //可附加的扩展}//代码在protos/common/common.pb.go```
补充HeaderType:
```gotype HeaderType int32
const (HeaderType_MESSAGE HeaderType = 0HeaderType_CONFIG HeaderType = 1HeaderType_CONFIG_UPDATE HeaderType = 2HeaderType_ENDORSER_TRANSACTION HeaderType = 3HeaderType_ORDERER_TRANSACTION HeaderType = 4HeaderType_DELIVER_SEEK_INFO HeaderType = 5HeaderType_CHAINCODE_PACKAGE HeaderType = 6)//代码在protos/common/common.pb.go```
SignatureHeader结构体：
```gotype SignatureHeader struct {Creator []byte //消息的创建者, 指定为证书链Nonce []byte //可能只使用一次的任意数字，可用于检测重播攻击}//代码在protos/common/common.pb.go```
### 2.3、Transaction相关结构体
Transaction结构体：
```gotype Transaction struct {Actions []*TransactionAction //Payload.Data是个TransactionAction数组，容纳每个交易}//代码在protos/peer/transaction.pb.go```
TransactionAction结构体：
```gotype TransactionAction struct {Header []bytePayload []byte}//代码在protos/peer/transaction.pb.go```
### 2.4、ChaincodeActionPayload相关结构体
ChaincodeActionPayload结构体：
```gotype ChaincodeActionPayload struct {ChaincodeProposalPayload []byteAction *ChaincodeEndorsedAction}//代码在protos/peer/transaction.pb.go```
ChaincodeEndorsedAction结构体：
```gotype ChaincodeEndorsedAction struct {ProposalResponsePayload []byte //ProposalResponsePayload序列化Endorsements []*Endorsement}//代码在protos/peer/transaction.pb.go```
ProposalResponsePayload结构体：
```gotype ProposalResponsePayload struct {ProposalHash []byteExtension []byte //ChaincodeAction序列化}//代码在protos/peer/proposal_response.pb.go```
ChaincodeAction结构体：
```gotype ChaincodeAction struct {Results []byte //TxRwSet序列化Events []byteResponse *ResponseChaincodeId *ChaincodeID}//代码在protos/peer/proposal.pb.go```
## 3、交易验证代码TxValidationFlags
TxValidationFlags是交易验证代码的数组，在commiter验证块时使用。
```gotype TxValidationFlags []uint8
//创建TxValidationFlags数组func NewTxValidationFlags(size int) TxValidationFlags//为指定的交易设置交易验证代码func (obj TxValidationFlags) SetFlag(txIndex int, flag peer.TxValidationCode) //获取指定交易的交易验证代码func (obj TxValidationFlags) Flag(txIndex int) peer.TxValidationCode //检查指定的交易是否有效func (obj TxValidationFlags) IsValid(txIndex int) bool//检查指定的交易是否无效func (obj TxValidationFlags) IsInvalid(txIndex int) bool//指定交易的交易验证代码与flag比较，相同为truefunc (obj TxValidationFlags) IsSetTo(txIndex int, flag peer.TxValidationCode) bool//代码在core/ledger/util/txvalidationflags.go```
补充peer.TxValidationCode：
```gotype TxValidationCode int32
const (TxValidationCode_VALID TxValidationCode = 0TxValidationCode_NIL_ENVELOPE TxValidationCode = 1TxValidationCode_BAD_PAYLOAD TxValidationCode = 2TxValidationCode_BAD_COMMON_HEADER TxValidationCode = 3TxValidationCode_BAD_CREATOR_SIGNATURE TxValidationCode = 4TxValidationCode_INVALID_ENDORSER_TRANSACTION TxValidationCode = 5TxValidationCode_INVALID_CONFIG_TRANSACTION TxValidationCode = 6TxValidationCode_UNSUPPORTED_TX_PAYLOAD TxValidationCode = 7TxValidationCode_BAD_PROPOSAL_TXID TxValidationCode = 8TxValidationCode_DUPLICATE_TXID TxValidationCode = 9TxValidationCode_ENDORSEMENT_POLICY_FAILURE TxValidationCode = 10TxValidationCode_MVCC_READ_CONFLICT TxValidationCode = 11TxValidationCode_PHANTOM_READ_CONFLICT TxValidationCode = 12TxValidationCode_UNKNOWN_TX_TYPE TxValidationCode = 13TxValidationCode_TARGET_CHAIN_NOT_FOUND TxValidationCode = 14TxValidationCode_MARSHAL_TX_ERROR TxValidationCode = 15TxValidationCode_NIL_TXACTION TxValidationCode = 16TxValidationCode_EXPIRED_CHAINCODE TxValidationCode = 17TxValidationCode_CHAINCODE_VERSION_CONFLICT TxValidationCode = 18TxValidationCode_BAD_HEADER_EXTENSION TxValidationCode = 19TxValidationCode_BAD_CHANNEL_HEADER TxValidationCode = 20TxValidationCode_BAD_RESPONSE_PAYLOAD TxValidationCode = 21TxValidationCode_BAD_RWSET TxValidationCode = 22TxValidationCode_ILLEGAL_WRITESET TxValidationCode = 23TxValidationCode_INVALID_OTHER_REASON TxValidationCode = 255)//代码在protos/peer/transaction.pb.go```
## 4、交易相关部分工具函数（protos/utils包）
putils更详细内容，参考：[Fabric 1.0源代码笔记 之 putils（protos/utils工具包）]
## 5、RWSet（读写集）
RWSet更详细内容，参考：[Fabric 1.0源代码笔记 之 Tx #RWSet（读写集）]
## 6、version.Height结构体及方法
```gotype Height struct {BlockNum uint64 //区块编号TxNum uint64 //交易编号}
func NewHeight(blockNum, txNum uint64) *Height //构造Heightfunc NewHeightFromBytes(b []byte) (*Height, int) //[]byte反序列化构造Heightfunc (h *Height) ToBytes() []byte //Height序列化func (h *Height) Compare(h1 *Height) int //比较两个Heightfunc AreSame(h1 *Height, h2 *Height) bool //比较两个Height是否相等//代码在core/ledger/kvledger/txmgmt/version/version.go```
## 7、Validator接口及实现（验证读写集）
### 7.1、Validator接口定义
```gotype Validator interface {//验证和准备批处理ValidateAndPrepareBatch(block *common.Block, doMVCCValidation bool) (*statedb.UpdateBatch, error)}//代码在core/ledger/kvledger/txmgmt/validator/validator.go```
### 7.2、Validator接口实现
Validator接口实现，即statebasedval.Validator结构体及方法。Validator结构体定义如下：
```gotype Validator struct {db statedb.VersionedDB //statedb}//代码在core/ledger/kvledger/txmgmt/validator/statebasedval/state_based_validator.go```
涉及方法如下：
```go//构造Validatorfunc NewValidator(db statedb.VersionedDB) *Validator//验证背书交易func (v *Validator) validateEndorserTX(envBytes []byte, doMVCCValidation bool, updates *statedb.UpdateBatch) (*rwsetutil.TxRwSet, peer.TxValidationCode, error)//验证和准备批处理，Block中写集加入批处理func (v *Validator) ValidateAndPrepareBatch(block *common.Block, doMVCCValidation bool) (*statedb.UpdateBatch, error)func addWriteSetToBatch(txRWSet *rwsetutil.TxRwSet, txHeight *version.Height, batch *statedb.UpdateBatch)func (v *Validator) validateTx(txRWSet *rwsetutil.TxRwSet, updates *statedb.UpdateBatch) (peer.TxValidationCode, error)func (v *Validator) validateReadSet(ns string, kvReads []*kvrwset.KVRead, updates *statedb.UpdateBatch) (bool, error)func (v *Validator) validateKVRead(ns string, kvRead *kvrwset.KVRead, updates *statedb.UpdateBatch) (bool, error)func (v *Validator) validateRangeQueries(ns string, rangeQueriesInfo []*kvrwset.RangeQueryInfo, updates *statedb.UpdateBatch) (bool, error)func (v *Validator) validateRangeQuery(ns string, rangeQueryInfo *kvrwset.RangeQueryInfo, updates *statedb.UpdateBatch) (bool, error)//代码在core/ledger/kvledger/txmgmt/validator/statebasedval/state_based_validator.go```
func (v *Validator) ValidateAndPrepareBatch(block *common.Block, doMVCCValidation bool) (*statedb.UpdateBatch, error)代码如下：
```goupdates := statedb.NewUpdateBatch() //构造批处理//type TxValidationFlags []uint8txsFilter := util.TxValidationFlags(block.Metadata.Metadata[common.BlockMetadataIndex_TRANSACTIONS_FILTER])if len(txsFilter) == 0 {txsFilter = util.NewTxValidationFlags(len(block.Data.Data))block.Metadata.Metadata[common.BlockMetadataIndex_TRANSACTIONS_FILTER] = txsFilter}
for txIndex, envBytes := range block.Data.Data {if txsFilter.IsInvalid(txIndex) { //验证交易是否有效continue}env, err := putils.GetEnvelopeFromBlock(envBytes) //Envelopepayload, err := putils.GetPayload(env) //Payloadchdr, err := putils.UnmarshalChannelHeader(payload.Header.ChannelHeader) //ChannelHeadertxType := common.HeaderType(chdr.Type) //HeaderType
if txType != common.HeaderType_ENDORSER_TRANSACTION {continue}//验证背书交易，获取读写集txRWSet, txResult, err := v.validateEndorserTX(envBytes, doMVCCValidation, updates)txsFilter.SetFlag(txIndex, txResult)if txRWSet != nil {committingTxHeight := version.NewHeight(block.Header.Number, uint64(txIndex))//读写集中写集加入批处理addWriteSetToBatch(txRWSet, committingTxHeight, updates)txsFilter.SetFlag(txIndex, peer.TxValidationCode_VALID)}}block.Metadata.Metadata[common.BlockMetadataIndex_TRANSACTIONS_FILTER] = txsFilterreturn updates, nil
//代码在core/ledger/kvledger/txmgmt/validator/statebasedval/state_based_validator.go```
## 8、TxMgr接口及实现（交易管理）
### 8.1、TxMgr接口定义
```gotype TxMgr interface {NewQueryExecutor() (ledger.QueryExecutor, error)NewTxSimulator() (ledger.TxSimulator, error)ValidateAndPrepare(block *common.Block, doMVCCValidation bool) error//返回statedb一致的最高事务的高度GetLastSavepoint() (*version.Height, error)ShouldRecover(lastAvailableBlock uint64) (bool, uint64, error)CommitLostBlock(block *common.Block) errorCommit() errorRollback()Shutdown()}//代码在core/ledger/kvledger/txmgmt/txmgr/txmgr.go```
### 8.2、TxMgr接口实现
TxMgr接口实现，即LockBasedTxMgr结构体及方法。LockBasedTxMgr结构体如下：
```gotype LockBasedTxMgr struct {db statedb.VersionedDB //statedbvalidator validator.Validator //Validatorbatch *statedb.UpdateBatch //批处理currentBlock *common.Block //BlockcommitRWLock sync.RWMutex //锁}//代码在core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/lockbased_txmgr.go```
涉及方法如下：
```go//构造LockBasedTxMgrfunc NewLockBasedTxMgr(db statedb.VersionedDB) *LockBasedTxMgr//调取txmgr.db.GetLatestSavePoint()，返回statedb一致的最高事务的高度func (txmgr *LockBasedTxMgr) GetLastSavepoint() (*version.Height, error)//调取newQueryExecutor(txmgr)func (txmgr *LockBasedTxMgr) NewQueryExecutor() (ledger.QueryExecutor, error)func (txmgr *LockBasedTxMgr) NewTxSimulator() (ledger.TxSimulator, error)//验证Block，并从Block中获取写集加入批处理txmgr.batchfunc (txmgr *LockBasedTxMgr) ValidateAndPrepare(block *common.Block, doMVCCValidation bool) errorfunc (txmgr *LockBasedTxMgr) Shutdown()//执行txmgr.batch，func (txmgr *LockBasedTxMgr) Commit() errorfunc (txmgr *LockBasedTxMgr) Rollback()func (txmgr *LockBasedTxMgr) ShouldRecover(lastAvailableBlock uint64) (bool, uint64, error)func (txmgr *LockBasedTxMgr) CommitLostBlock(block *common.Block) error//代码在core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/lockbased_txmgr.go```
### 8.3、lockBasedQueryExecutor结构体及方法（实现ledger.QueryExecutor接口）
```gotype lockBasedQueryExecutor struct {helper *queryHelperid string}
func newQueryExecutor(txmgr *LockBasedTxMgr) *lockBasedQueryExecutor func (q *lockBasedQueryExecutor) GetState(ns string, key string) ([]byte, error)func (q *lockBasedQueryExecutor) GetStateMultipleKeys(namespace string, keys []string) ([][]byte, error)func (q *lockBasedQueryExecutor) GetStateRangeScanIterator(namespace string, startKey string, endKey string) (ledger.ResultsIterator, error)func (q *lockBasedQueryExecutor) ExecuteQuery(namespace, query string) (ledger.ResultsIterator, error)func (q *lockBasedQueryExecutor) Done()//代码在core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/lockbased_query_executer.go```
### 8.4、queryHelper结构体及方法
queryHelper结构体及方法：
```gotype queryHelper struct {txmgr *LockBasedTxMgr //LockBasedTxMgrrwsetBuilder *rwsetutil.RWSetBuilder //读写集工具itrs []*resultsItrerr errordoneInvoked bool //是否调用完成}
//statedb中获取versionedValue，并加入rwsetBuilder的nsRWs.readMap中func (h *queryHelper) getState(ns string, key string) ([]byte, error)//statedb中获取多个versionedValue，并加入rwsetBuilder的nsRWs.readMap中func (h *queryHelper) getStateMultipleKeys(namespace string, keys []string) ([][]byte, error)//构造resultsItr，并加入queryHelper.itrsfunc (h *queryHelper) getStateRangeScanIterator(namespace string, startKey string, endKey string) (commonledger.ResultsIterator, error)执行查询并构造queryResultsItrfunc (h *queryHelper) executeQuery(namespace, query string) (commonledger.ResultsIterator, error)//donefunc (h *queryHelper) done()func (h *queryHelper) checkDone()//代码在core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/helper.go```
resultsItr结构体及方法：
```gotype resultsItr struct {ns stringendKey stringdbItr statedb.ResultsIteratorrwSetBuilder *rwsetutil.RWSetBuilderrangeQueryInfo *kvrwset.RangeQueryInforangeQueryResultsHelper *rwsetutil.RangeQueryResultsHelper}
func newResultsItr(ns string, startKey string, endKey string, db statedb.VersionedDB, rwsetBuilder *rwsetutil.RWSetBuilder, enableHashing bool, maxDegree uint32) (*resultsItr, error)func (itr *resultsItr) Next() (commonledger.QueryResult, error)func (itr *resultsItr) updateRangeQueryInfo(queryResult statedb.QueryResult)func (itr *resultsItr) Close()//代码在core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/helper.go```
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