Remove write state from store and minor changes

Use simplified return pattern. Change to var for slice declarations and
simplified read-write-set unmarshal.

Signed-off-by: Stanislav Jakuschevskij <stas@two-giants.com>

off_chain_data/application-go/parser/block.go

@@ -46,7 +46,7 @@ func (b *Block) unmarshalTransactions() ([]*Transaction, error) {
 }
 
 func (b *Block) unmarshalEnvelopes() ([]*common.Envelope, error) {
-	result := []*common.Envelope{}
+	var result []*common.Envelope
 	for _, blockData := range b.block.GetData().GetData() {
 		envelope := &common.Envelope{}
 		if err := proto.Unmarshal(blockData, envelope); err != nil {
@@ -58,7 +58,7 @@ func (b *Block) unmarshalEnvelopes() ([]*common.Envelope, error) {
 }
 
 func (*Block) unmarshalPayloadsFrom(envelopes []*common.Envelope) ([]*common.Payload, error) {
-	result := []*common.Payload{}
+	var result []*common.Payload
 	for _, envelope := range envelopes {
 		commonPayload := &common.Payload{}
 		if err := proto.Unmarshal(envelope.GetPayload(), commonPayload); err != nil {
@@ -72,7 +72,7 @@ func (*Block) unmarshalPayloadsFrom(envelopes []*common.Envelope) ([]*common.Pay
 func (b *Block) parse(commonPayloads []*common.Payload) ([]*payload, error) {
 	validationCodes := b.block.GetMetadata().GetMetadata()[common.BlockMetadataIndex_TRANSACTIONS_FILTER]
 
-	result := []*payload{}
+	var result []*payload
 	for i, commonPayload := range commonPayloads {
 		statusCode := validationCodes[i]
 
@@ -90,7 +90,7 @@ func (b *Block) parse(commonPayloads []*common.Payload) ([]*payload, error) {
 }
 
 func (*Block) createTransactionsFrom(payloads []*payload) []*Transaction {
-	result := []*Transaction{}
+	var result []*Transaction
 	for _, payload := range payloads {
 		result = append(result, newTransaction(payload))
 	}

off_chain_data/application-go/parser/endorserTransaction.go

@@ -25,12 +25,7 @@ func (p *endorserTransaction) unmarshalReadWriteSets() ([]*readWriteSet, error)
 		return nil, err
 	}
 
-	chaincodeEndorsedActions, err := p.extractChaincodeEndorsedActionsFrom(chaincodeActionPayloads)
+	proposalResponsePayloads, err := p.unmarshalProposalResponsePayloadsFrom(chaincodeActionPayloads)
-	if err != nil {
-		return nil, err
-	}
-
-	proposalResponsePayloads, err := p.unmarshalProposalResponsePayloadsFrom(chaincodeEndorsedActions)
 	if err != nil {
 		return nil, err
 	}
@@ -49,31 +44,22 @@ func (p *endorserTransaction) unmarshalReadWriteSets() ([]*readWriteSet, error)
 }
 
 func (p *endorserTransaction) unmarshalChaincodeActionPayloads() ([]*peer.ChaincodeActionPayload, error) {
-	result := []*peer.ChaincodeActionPayload{}
+	var result []*peer.ChaincodeActionPayload
 	for _, transactionAction := range p.transaction.GetActions() {
 		chaincodeActionPayload := &peer.ChaincodeActionPayload{}
 		if err := proto.Unmarshal(transactionAction.GetPayload(), chaincodeActionPayload); err != nil {
 			return nil, err
 		}
-
 		result = append(result, chaincodeActionPayload)
 	}
 	return result, nil
 }
 
-func (*endorserTransaction) extractChaincodeEndorsedActionsFrom(chaincodeActionPayloads []*peer.ChaincodeActionPayload) ([]*peer.ChaincodeEndorsedAction, error) {
+func (*endorserTransaction) unmarshalProposalResponsePayloadsFrom(chaincodeActionPayloads []*peer.ChaincodeActionPayload) ([]*peer.ProposalResponsePayload, error) {
-	result := []*peer.ChaincodeEndorsedAction{}
+	var result []*peer.ProposalResponsePayload
-	for _, payload := range chaincodeActionPayloads {
+	for _, chaincodeActionPayload := range chaincodeActionPayloads {
-		result = append(result, payload.GetAction())
-	}
-	return result, nil
-}
-
-func (*endorserTransaction) unmarshalProposalResponsePayloadsFrom(chaincodeEndorsedActions []*peer.ChaincodeEndorsedAction) ([]*peer.ProposalResponsePayload, error) {
-	result := []*peer.ProposalResponsePayload{}
-	for _, endorsedAction := range chaincodeEndorsedActions {
 		proposalResponsePayload := &peer.ProposalResponsePayload{}
-		if err := proto.Unmarshal(endorsedAction.GetProposalResponsePayload(), proposalResponsePayload); err != nil {
+		if err := proto.Unmarshal(chaincodeActionPayload.GetAction().GetProposalResponsePayload(), proposalResponsePayload); err != nil {
 			return nil, err
 		}
 		result = append(result, proposalResponsePayload)
@@ -82,7 +68,7 @@ func (*endorserTransaction) unmarshalProposalResponsePayloadsFrom(chaincodeEndor
 }
 
 func (*endorserTransaction) unmarshalChaincodeActionsFrom(proposalResponsePayloads []*peer.ProposalResponsePayload) ([]*peer.ChaincodeAction, error) {
-	result := []*peer.ChaincodeAction{}
+	var result []*peer.ChaincodeAction
 	for _, proposalResponsePayload := range proposalResponsePayloads {
 		chaincodeAction := &peer.ChaincodeAction{}
 		if err := proto.Unmarshal(proposalResponsePayload.GetExtension(), chaincodeAction); err != nil {
@@ -94,7 +80,7 @@ func (*endorserTransaction) unmarshalChaincodeActionsFrom(proposalResponsePayloa
 }
 
 func (*endorserTransaction) unmarshalTxReadWriteSetsFrom(chaincodeActions []*peer.ChaincodeAction) ([]*rwset.TxReadWriteSet, error) {
-	result := []*rwset.TxReadWriteSet{}
+	var result []*rwset.TxReadWriteSet
 	for _, chaincodeAction := range chaincodeActions {
 		txReadWriteSet := &rwset.TxReadWriteSet{}
 		if err := proto.Unmarshal(chaincodeAction.GetResults(), txReadWriteSet); err != nil {
@@ -106,7 +92,7 @@ func (*endorserTransaction) unmarshalTxReadWriteSetsFrom(chaincodeActions []*pee
 }
 
 func (*endorserTransaction) parseReadWriteSets(txReadWriteSets []*rwset.TxReadWriteSet) []*readWriteSet {
-	result := []*readWriteSet{}
+	var result []*readWriteSet
 	for _, txReadWriteSet := range txReadWriteSets {
 		parsedReadWriteSet := parseReadWriteSet(txReadWriteSet)
 		result = append(result, parsedReadWriteSet)

off_chain_data/application-go/parser/transaction.go

@@ -27,11 +27,10 @@ func (t *Transaction) NamespaceReadWriteSets() ([]*NamespaceReadWriteSet, error)
 		return nil, err
 	}
 
-	result := []*NamespaceReadWriteSet{}
+	var result []*NamespaceReadWriteSet
 	for _, readWriteSet := range txReadWriteSets {
 		result = append(result, readWriteSet.namespaceReadWriteSets()...)
 	}
-
 	return result, nil
 }
 

off_chain_data/application-go/store.go

@@ -10,13 +10,12 @@ import (
 var errExpected = errors.New("expected error: simulated write failure")
 
 type offChainStore struct {
-	writes, path                            string
+	path                                    string
 	simulatedFailureCount, transactionCount uint
 }
 
 func newOffChainStore(path string, simulatedFailureCount uint) *offChainStore {
 	return &offChainStore{
-		"",
 		path,
 		uint(simulatedFailureCount),
 		0,
@@ -30,17 +29,12 @@ func (ocs *offChainStore) write(data ledgerUpdate) error {
 		return err
 	}
 
-	ocs.clearLastWrites()
+	writes, err := ocs.marshal(data.Writes)
-
+	if err != nil {
-	if err := ocs.marshal(data.Writes); err != nil {
 		return err
 	}
 
-	if err := ocs.persist(); err != nil {
+	return ocs.persist(writes)
-		return err
-	}
-
-	return nil
 }
 
 func (ocs *offChainStore) simulateFailureIfRequired() error {
@@ -54,30 +48,27 @@ func (ocs *offChainStore) simulateFailureIfRequired() error {
 	return nil
 }
 
-func (ocs *offChainStore) clearLastWrites() {
+func (ocs *offChainStore) marshal(writes []write) (string, error) {
-	ocs.writes = ""
+	var marshaledWrites string
-}
-
-func (ocs *offChainStore) marshal(writes []write) error {
 	for _, write := range writes {
 		marshaled, err := json.Marshal(write)
 		if err != nil {
-			return err
+			return "", err
 		}
 
-		ocs.writes += string(marshaled) + "\n"
+		marshaledWrites += string(marshaled) + "\n"
 	}
 
-	return nil
+	return marshaledWrites, nil
 }
 
-func (ocs *offChainStore) persist() error {
+func (ocs *offChainStore) persist(marshaledWrites string) error {
 	f, err := os.OpenFile(ocs.path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
 	if err != nil {
 		return err
 	}
 
-	if _, writeErr := f.Write([]byte(ocs.writes)); writeErr != nil {
+	if _, writeErr := f.Write([]byte(marshaledWrites)); writeErr != nil {
 		if closeErr := f.Close(); closeErr != nil {
 			return fmt.Errorf("write error: %v, close error: %v", writeErr, closeErr)
 		}
@@ -85,9 +76,5 @@ func (ocs *offChainStore) persist() error {
 		return writeErr
 	}
 
-	if err := f.Close(); err != nil {
+	return f.Close()
-		return err
-	}
-
-	return nil
 }

off_chain_data/application-go/transact.go

@@ -27,14 +27,9 @@ func transact(clientConnection grpc.ClientConnInterface) error {
 	}()
 
 	contract := gateway.GetNetwork(channelName).GetContract(chaincodeName)
-
 	smartContract := atb.NewAssetTransferBasic(contract)
 	app := newTransactApp(smartContract)
-	if err := app.run(); err != nil {
+	return app.run()
-		return err
-	}
-
-	return nil
 }
 
 type transactApp struct {
@@ -71,11 +66,7 @@ func (t *transactApp) run() error {
 
 	wg.Wait()
 
-	if err := context.Cause(ctx); err != nil {
+	return context.Cause(ctx)
-		return err
-	}
-
-	return nil
 }
 
 func (t *transactApp) transact() error {