区块链教程Fabric1.0源代码分析Tx（Transaction 交易）二

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

type Height struct {
    BlockNum uint64 //区块编号
    TxNum    uint64 //交易编号
}

func NewHeight(blockNum, txNum uint64) *Height //构造Height
func NewHeightFromBytes(b []byte) (*Height, int) //[]byte反序列化构造Height
func (h *Height) ToBytes() []byte //Height序列化
func (h *Height) Compare(h1 *Height) int //比较两个Height
func 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

type 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：

type 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：

//构造Validator
func 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：

updates := statedb.NewUpdateBatch() //构造批处理
//type TxValidationFlags []uint8
txsFilter := 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) //Envelope
    payload, err := putils.GetPayload(env) //Payload
    chdr, err := putils.UnmarshalChannelHeader(payload.Header.ChannelHeader) //ChannelHeader
    txType := 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] = txsFilter
return 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

type 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) error
    Commit() error
    Rollback()
    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：

type LockBasedTxMgr struct {
    db           statedb.VersionedDB //statedb
    validator    validator.Validator //Validator
    batch        *statedb.UpdateBatch //批处理
    currentBlock *common.Block //Block
    commitRWLock sync.RWMutex //锁
}
//代码在core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/lockbased_txmgr.go