Implement PreprocessTxs

app/abci.go

@@ -0,0 +1,144 @@
+package app
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"sort"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/lazyledger/lazyledger-app/x/lazyledgerapp/types"
+	abci "github.com/lazyledger/lazyledger-core/abci/types"
+	core "github.com/lazyledger/lazyledger-core/proto/tendermint/types"
+)
+
+// This file should contain all of the altered ABCI methods
+
+// PreprocessTxs fullfills the lazyledger-core version of the ACBI interface, by
+// performing basic validation for the incoming txs, and by cleanly separating
+// share messages from transactions
+func (app *App) PreprocessTxs(txs abci.RequestPreprocessTxs) abci.ResponsePreprocessTxs {
+	squareSize := app.SquareSize()
+	shareCounter := uint64(0)
+	var shareMsgs []*core.Message
+	var processedTxs [][]byte
+	for _, rawTx := range txs.Txs {
+		// decode the Tx
+		tx, err := app.txConfig.TxDecoder()(rawTx)
+		if err != nil {
+			continue
+		}
+
+		// don't process the tx if the transaction doesn't contain a
+		// PayForMessage sdk.Msg
+		if !hasWirePayForMessage(tx) {
+			processedTxs = append(processedTxs, rawTx)
+			continue
+		}
+
+		// only support transactions that contain a single sdk.Msg
+		if len(tx.GetMsgs()) != 1 {
+			continue
+		}
+
+		msg := tx.GetMsgs()[0]
+
+		// run basic validation on the transaction
+		err = tx.ValidateBasic()
+		if err != nil {
+			continue
+		}
+
+		// process the message
+		coreMsg, signedTx, err := app.processMsg(msg)
+		if err != nil {
+			continue
+		}
+
+		// increment the share counter by the number of shares taken by the message
+		sharesTaken := uint64(len(coreMsg.Data) / types.ShareSize)
+		shareCounter += sharesTaken
+
+		// if there are too many shares stop processing and return the transactions
+		if shareCounter > squareSize*squareSize {
+			break
+		}
+
+		// encode the processed tx
+		rawProcessedTx, err := app.appCodec.MarshalBinaryBare(signedTx)
+		if err != nil {
+			continue
+		}
+
+		// add the message and tx to the output
+		shareMsgs = append(shareMsgs, &coreMsg)
+		processedTxs = append(processedTxs, rawProcessedTx)
+	}
+
+	// sort messages lexigraphically
+	sort.Slice(shareMsgs, func(i, j int) bool {
+		return bytes.Compare(shareMsgs[i].NamespaceId, shareMsgs[j].NamespaceId) < 0
+	})
+
+	return abci.ResponsePreprocessTxs{
+		Txs:      processedTxs,
+		Messages: &core.Messages{MessagesList: shareMsgs},
+	}
+}
+
+func hasWirePayForMessage(tx sdk.Tx) bool {
+	for _, msg := range tx.GetMsgs() {
+		if msg.Type() == types.TypeMsgPayforMessage {
+			return true
+		}
+	}
+	return false
+}
+
+// processMsgs will perform the processing required by PreProcessTxs for a set
+// of sdk.Msg's from a single sdk.Tx
+func (app *App) processMsg(msg sdk.Msg) (core.Message, *types.TxSignedTransactionDataPayForMessage, error) {
+	squareSize := app.SquareSize()
+	// reject all msgs in tx if a single included msg is not correct type
+	wireMsg, ok := msg.(*types.MsgWirePayForMessage)
+	if !ok {
+		return core.Message{},
+			nil,
+			errors.New("transaction contained a message type other than types.MsgWirePayForMessage")
+	}
+
+	// make sure that a ShareCommitAndSignature of the correct size is
+	// included in the message
+	var shareCommit types.ShareCommitAndSignature
+	for _, commit := range wireMsg.MessageShareCommitment {
+		if commit.K == squareSize {
+			shareCommit = commit
+		}
+	}
+	// K == 0 means there was no share commit with the desired current square size
+	if shareCommit.K == 0 {
+		return core.Message{},
+			nil,
+			fmt.Errorf("No share commit for correct square size. Current square size: %d", squareSize)
+	}
+
+	// add the message to the list of core message to be returned to ll-core
+	coreMsg := core.Message{
+		NamespaceId: wireMsg.GetMessageNameSpaceId(),
+		Data:        wireMsg.GetMessage(),
+	}
+
+	// wrap the signed transaction data
+	sTxData, err := wireMsg.SignedTransactionDataPayForMessage(squareSize)
+	if err != nil {
+		return core.Message{}, nil, err
+	}
+
+	signedData := &types.TxSignedTransactionDataPayForMessage{
+		Message:   sTxData,
+		Signature: shareCommit.Signature,
+		PublicKey: wireMsg.PublicKey,
+	}
+
+	return coreMsg, signedData, nil
+}