private void fetchStoreAndValidateParentOutputs(ArrayList<Transaction> transactions)
throws WapiException {
Map<Sha256Hash, TransactionEx> parentTransactions = new HashMap<Sha256Hash, TransactionEx>();
Map<OutPoint, TransactionOutputEx> parentOutputs = new HashMap<OutPoint, TransactionOutputEx>();
// Find list of parent outputs to fetch
Collection<Sha256Hash> toFetch = new HashSet<Sha256Hash>();
for (Transaction t : transactions) {
for (TransactionInput in : t.inputs) {
if (in.outPoint.hash.equals(OutPoint.COINBASE_OUTPOINT.hash)) {
// Coinbase input, so no parent
continue;
}
TransactionOutputEx parentOutput = _backing.getParentTransactionOutput(in.outPoint);
if (parentOutput != null) {
// We already have the parent output, no need to fetch the entire
// parent transaction
parentOutputs.put(parentOutput.outPoint, parentOutput);
continue;
}
TransactionEx parentTransaction = _backing.getTransaction(in.outPoint.hash);
if (parentTransaction != null) {
// We had the parent transaction in our own transactions, no need to
// fetch it remotely
parentTransactions.put(parentTransaction.txid, parentTransaction);
} else {
// Need to fetch it
toFetch.add(in.outPoint.hash);
}
}
}
// Fetch missing parent transactions
if (toFetch.size() > 0) {
GetTransactionsResponse result =
_wapi.getTransactions(new GetTransactionsRequest(Wapi.VERSION, toFetch)).getResult();
for (TransactionEx tx : result.transactions) {
// Verify transaction hash. This is important as we don't want to
// have a transaction output associated with an outpoint that
// doesn't match.
// This is the end users protection against a rogue server that lies
// about the value of an output and makes you pay a large fee.
Sha256Hash hash = HashUtils.doubleSha256(tx.binary).reverse();
if (hash.equals(tx.txid)) {
parentTransactions.put(tx.txid, tx);
} else {
_logger.logError(
"Failed to validate transaction hash from server. Expected: "
+ tx.txid
+ " Calculated: "
+ hash);
throw new RuntimeException(
"Failed to validate transaction hash from server. Expected: "
+ tx.txid
+ " Calculated: "
+ hash);
}
}
}
// We should now have all parent transactions or parent outputs. There is
// a slight probability that one of them was not found due to double
// spends and/or malleability and network latency etc.
// Now figure out which parent outputs we need to persist
List<TransactionOutputEx> toPersist = new LinkedList<TransactionOutputEx>();
for (Transaction t : transactions) {
for (TransactionInput in : t.inputs) {
if (in.outPoint.hash.equals(OutPoint.COINBASE_OUTPOINT.hash)) {
// coinbase input, so no parent
continue;
}
TransactionOutputEx parentOutput = parentOutputs.get(in.outPoint);
if (parentOutput != null) {
// We had it all along
continue;
}
TransactionEx parentTex = parentTransactions.get(in.outPoint.hash);
if (parentTex != null) {
// Parent output not found, maybe we already have it
parentOutput = TransactionEx.getTransactionOutput(parentTex, in.outPoint.index);
toPersist.add(parentOutput);
continue;
}
_logger.logError("Parent transaction not found: " + in.outPoint.hash);
}
}
// Persist
for (TransactionOutputEx output : toPersist) {
_backing.putParentTransactionOutput(output);
}
}
