Merge pull request #127 from ubclaunchpad/126-allow-multiple-inputs-i…

…n-transactions

Pluralized Transaction Inputs

app/app.go

@@ -292,8 +292,8 @@ func (a *App) HandleTransaction(txn *blockchain.Transaction) {
 	a.Chain.RLock()
 	defer a.Chain.RUnlock()
 
-	validTransaction := a.Pool.Push(txn, a.Chain)
-	if validTransaction {
+	code := a.Pool.Push(txn, a.Chain)
+	if code == consensus.ValidTransaction {
 		log.Debug("Added transaction to pool from address: " + txn.Sender.Repr())
 	} else {
 		log.Debug("Bad transaction rejected from sender: " + txn.Sender.Repr())
@@ -477,7 +477,7 @@ func (a *App) makeBlockRequest(currentHead *blockchain.Block,
 
 // handleBlockResponse receives a block or nil from the newBlockChan and attempts
 // to validate it and add it to the blockchain, or it handles a protocol error
-// from the errChan. Returns whether the blockchain was modified and wether we
+// from the errChan. Returns whether the blockchain was modified and whether we
 // received an UpToDate response.
 func (a *App) handleBlockResponse(newBlockChan chan *blockchain.Block,
 	errChan chan *msg.ProtocolError) (changed bool, upToDate bool) {

app/app_test.go

@@ -19,7 +19,7 @@ import (
 )
 
 func init() {
-	log.SetLevel(log.DebugLevel)
+	log.SetLevel(log.ErrorLevel)
 }
 
 func TestPushHandlerNewBlock(t *testing.T) {
@@ -141,7 +141,7 @@ func TestHandleValidBlock(t *testing.T) {
 	bc, blk := blockchain.NewValidTestChainAndBlock()
 	a.Chain = bc
 	a.HandleBlock(blk)
-	assert.Equal(t, blk, a.Chain.Blocks[2])
+	assert.Equal(t, blk, a.Chain.Blocks[3])
 
 	// TODO: Assert miner restarted.
 	// TODO: Assert pool appropriately emptied.
@@ -237,14 +237,24 @@ func TestHandleBlockResponse(t *testing.T) {
 	a := createNewTestApp()
 	newBlockChan := make(chan *blockchain.Block, 1)
 	errChan := make(chan *msg.ProtocolError, 1)
-	newBlockChan <- a.Chain.RollBack()
+
+	// Roll the last block off of the chain, add to channel.
+	lastBlock := a.Chain.RollBack()
+	assert.NotNil(t, lastBlock)
+	newBlockChan <- lastBlock
+
+	// Handle the block.
 	changed, upToDate := a.handleBlockResponse(newBlockChan, errChan)
 	assert.True(t, changed)
 	assert.False(t, upToDate)
+
+	// Add an on-chain block to the handler (this shouldn't change the chain).
 	newBlockChan <- a.Chain.Blocks[1]
 	changed, upToDate = a.handleBlockResponse(newBlockChan, errChan)
 	assert.False(t, changed)
 	assert.False(t, upToDate)
+
+	// More stuff happens.
 	errChan <- msg.NewProtocolError(msg.UpToDate, "")
 	changed, upToDate = a.handleBlockResponse(newBlockChan, errChan)
 	assert.False(t, changed)
@@ -253,19 +263,30 @@ func TestHandleBlockResponse(t *testing.T) {
 	changed, upToDate = a.handleBlockResponse(newBlockChan, errChan)
 	assert.True(t, changed)
 	assert.False(t, upToDate)
-	assert.Equal(t, len(a.Chain.Blocks), 1)
+	assert.Equal(t, len(a.Chain.Blocks), 2)
 }
 
 func TestHandleWork(t *testing.T) {
 	a := createNewTestApp()
 	go a.HandleWork()
-	a.blockQueue <- a.Chain.RollBack()
-	time.Sleep(time.Second)
+
+	// Roll the last block off of the chain, add to channel (expect it added back).
+	lastBlock := a.Chain.RollBack()
 	assert.Equal(t, len(a.Chain.Blocks), 2)
+	a.blockQueue <- lastBlock
+	time.Sleep(time.Millisecond * 50)
+	assert.Equal(t, len(a.Chain.Blocks), 3)
+
+	// Kill the worker.
 	a.quitChan <- true
-	a.blockQueue <- a.Chain.RollBack()
-	time.Sleep(time.Second)
-	assert.Equal(t, len(a.Chain.Blocks), 1)
+
+	// Roll the last block off of the chain, add to channel
+	// (expect it not to be added back).
+	lastBlock = a.Chain.RollBack()
+	assert.Equal(t, len(a.Chain.Blocks), 2)
+	a.blockQueue <- lastBlock
+	time.Sleep(time.Millisecond * 50)
+	assert.Equal(t, len(a.Chain.Blocks), 2)
 }
 
 func TestPay(t *testing.T) {

app/user.go

@@ -3,6 +3,8 @@ package app
 import (
 	"errors"
 
+	"github.com/ubclaunchpad/cumulus/consensus"
+
 	"github.com/ubclaunchpad/cumulus/blockchain"
 	"github.com/ubclaunchpad/cumulus/msg"
 
@@ -41,7 +43,7 @@ func (a *App) Pay(to string, amount uint64) error {
 	tbody := blockchain.TxBody{
 		Sender: wallet.Public(),
 		// TODO: Collect inputs.
-		Input: blockchain.TxHashPointer{},
+		Inputs: []blockchain.TxHashPointer{},
 		Outputs: []blockchain.TxOutput{
 			blockchain.TxOutput{
 				Recipient: to,
@@ -59,7 +61,8 @@ func (a *App) Pay(to string, amount uint64) error {
 		}
 
 		// The transaction must be added to the pool.
-		if !pool.Push(txn, a.Chain) {
+		code := pool.Push(txn, a.Chain)
+		if code != consensus.ValidTransaction {
 			return errors.New("transaction validation failed")
 		}
 

blockchain/block.go

@@ -69,7 +69,7 @@ func (b *Block) Len() int {
 }
 
 // Marshal converts a Block to a byte slice.
-func (b *Block) Marshal() []byte {
+func (b Block) Marshal() []byte {
 	var buf []byte
 	buf = append(buf, b.BlockHeader.Marshal()...)
 	for _, t := range b.Transactions {

blockchain/blockchain.go

@@ -84,17 +84,32 @@ func (bc *BlockChain) LastBlock() *Block {
 	return bc.Blocks[len(bc.Blocks)-1]
 }
 
-// GetInputTransaction returns the input Transaction to t. If the input does
-// not exist, then GetInputTransaction returns nil.
-func (bc *BlockChain) GetInputTransaction(t *Transaction) *Transaction {
-	if t.Input.BlockNumber > uint32(len(bc.Blocks)) {
+// GetInputTransaction returns the input Transaction referenced by TxHashPointer.
+// If the Transaction does not exist, then GetInputTransaction returns nil.
+func (bc *BlockChain) GetInputTransaction(t *TxHashPointer) *Transaction {
+	if t.BlockNumber > uint32(len(bc.Blocks)) {
 		return nil
 	}
-	b := bc.Blocks[t.Input.BlockNumber]
-	if t.Input.Index > uint32(len(b.Transactions)) {
+	b := bc.Blocks[t.BlockNumber]
+	if t.Index > uint32(len(b.Transactions)) {
 		return nil
 	}
-	return b.Transactions[t.Input.Index]
+	return b.Transactions[t.Index]
+}
+
+// GetAllInputs returns all the transactions referenced by a transaction
+// as inputs. Returns an error if any of the transactios requested could
+// not be found.
+func (bc *BlockChain) GetAllInputs(t *Transaction) ([]*Transaction, error) {
+	txns := []*Transaction{}
+	for _, tx := range t.Inputs {
+		nextTxn := bc.GetInputTransaction(&tx)
+		if nextTxn == nil {
+			return nil, errors.New("input transaction not found")
+		}
+		txns = append(txns, nextTxn)
+	}
+	return txns, nil
 }
 
 // ContainsTransaction returns true if the BlockChain contains the transaction

blockchain/genesis.go

@@ -15,15 +15,16 @@ func Genesis(miner Address, target Hash, blockReward uint64, extraData []byte) *
 		Amount:    blockReward,
 		Recipient: miner.Repr(),
 	}
+	cbInput := TxHashPointer{
+		BlockNumber: 0,
+		Hash:        NilHash,
+		Index:       0,
+	}
 
 	cbTx := &Transaction{
 		TxBody: TxBody{
-			Sender: NilAddr,
-			Input: TxHashPointer{
-				BlockNumber: 0,
-				Hash:        NilHash,
-				Index:       0,
-			},
+			Sender:  NilAddr,
+			Inputs:  []TxHashPointer{cbInput},
 			Outputs: []TxOutput{cbReward},
 		},
 		Sig: NilSig,