/**
* Restore the UTXO in a Coin at a given COutPoint
* @param undo The Coin to be restored.
* @param view The coins view to which to apply the changes.
* @param out The out point that corresponds to the tx input.
* @return A DisconnectResult as an int
*/
int CViewManager::ApplyTxInUndo(Coin &&undo, CCoinsViewCache &view, const COutPoint &out)
{
bool fClean = true;
if (view.HaveCoin(out))
fClean = false; // overwriting transaction output
if (undo.nHeight == 0)
{
// Missing undo metadata (height and coinbase). Older versions included this
// information only in undo records for the last spend of a transactions'
// outputs. This implies that it must be present for some other output of the same tx.
const Coin &alternate = AccessByTxid(view, out.hash);
if (!alternate.IsSpent())
{
undo.nHeight = alternate.nHeight;
undo.fCoinBase = alternate.fCoinBase;
} else
{
return DISCONNECT_FAILED; // adding output for transaction without known metadata
}
}
// The potential_overwrite parameter to AddCoin is only allowed to be false if we know for
// sure that the coin did not already exist in the cache. As we have queried for that above
// using HaveCoin, we don't need to guess. When fClean is false, a coin already existed and
// it is an overwrite.
view.AddCoin(out, std::move(undo), !fClean);
return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
}
void AddCoins(CCoinsViewCache& cache, const CTransaction &tx, int nHeight, bool check) {
bool fCoinbase = tx.IsCoinBase();
const uint256& txid = tx.GetHash();
for (size_t i = 0; i < tx.vout.size(); ++i) {
bool overwrite = check ? cache.HaveCoin(COutPoint(txid, i)) : fCoinbase;
// Always set the possible_overwrite flag to AddCoin for coinbase txn, in order to correctly
// deal with the pre-BIP30 occurrences of duplicate coinbase transactions.
cache.AddCoin(COutPoint(txid, i), Coin(tx.vout[i], nHeight, fCoinbase), overwrite);
}
}