LBRYCommunity/lbcd
1
0
Fork 0
Code Issues 17 Pull requests 4 Projects Releases 28 Packages Wiki Activity

Allow tx inputs to use txns earlier in same block.

Browse source 
It is acceptable for a transaction input in a block to reference the
output of another transaction in the same block only if the referenced
transaction comes before the transaction referencing it.
This commit is contained in:
Dave Collins 2013-07-29 15:48:52 -05:00
parent e82c97be3b
commit c3b330e42d
1 changed files with 23 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

35
txlookup.go
View file

@ -193,16 +193,17 @@ func (b *BlockChain) fetchTxList(node *blockNode, txList []*btcwire.ShaHash) (ma
// for more details on what the point of view entails.
func (b *BlockChain) fetchInputTransactions(node *blockNode, block *btcutil.Block) (map[btcwire.ShaHash]*txData, error) {
// Build a map of in-flight transactions because some of the inputs in
// this block could be referencing other transactions in this block
// which are not yet in the chain.
txInFlight := map[btcwire.ShaHash]*btcwire.MsgTx{}
for i, tx := range block.MsgBlock().Transactions {
// this block could be referencing other transactions earlier in this
// block which are not yet in the chain.
txInFlight := map[btcwire.ShaHash]int{}
transactions := block.MsgBlock().Transactions
for i := range transactions {
// Get transaction hash. It's safe to ignore the error since
// it's already cached in the nominal code path and the only
// way it can fail is if the index is out of range which is
// impossible here.
txHash, _ := block.TxSha(i)
txInFlight[*txHash] = tx
txInFlight[*txHash] = i
}
// Loop through all of the transaction inputs (except for the coinbase
@ -210,7 +211,7 @@ func (b *BlockChain) fetchInputTransactions(node *blockNode, block *btcutil.Bloc
// what is already known (in-flight).
var txNeededList []*btcwire.ShaHash
txStore := make(map[btcwire.ShaHash]*txData)
for _, tx := range block.MsgBlock().Transactions[1:] {
for i, tx := range transactions[1:] {
for _, txIn := range tx.TxIn {
// Add an entry to the transaction store for the needed
// transaction with it set to missing by default.
@ -218,13 +219,23 @@ func (b *BlockChain) fetchInputTransactions(node *blockNode, block *btcutil.Bloc
txD := &txData{hash: originHash, err: btcdb.TxShaMissing}
txStore[*originHash] = txD
// The transaction is already in-flight, so update the
// transaction store acccordingly. Otherwise, we need
// it.
if tx, ok := txInFlight[*originHash]; ok {
txD.tx = tx
// It is acceptable for a transaction input to reference
// the output of another transaction in this block only
// if the referenced transaction comes before the
// current one in this block. Update the transaction
// store acccordingly when this is the case. Otherwise,
// we still need the transaction.
//
// NOTE: The >= is correct here because i is one less
// than the actual position of the transaction within
// the block due to skipping the coinbase.
if inFlightIndex, ok := txInFlight[*originHash]; ok &&
i >= inFlightIndex {
originTx := transactions[inFlightIndex]
txD.tx = originTx
txD.blockHeight = node.height
txD.spent = make([]bool, len(tx.TxOut))
txD.spent = make([]bool, len(originTx.TxOut))
txD.err = nil
} else {
txNeededList = append(txNeededList, originHash)