Method FundTransaction

src/wallet.cpp:3196–3256

}

bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, bool overrideEstimatedFeeRate, int& nChangePosInOut, std::string& strFailReason,
                              bool lockUnspents, const std::set<int>& setSubtractFeeFromOutputs, CCoinControl* coinControl)
{
    //assert(coinControl != nullptr);
    std::vector<CRecipient> vecSend;

    // Turn the txout set into a CRecipient vector.
    for (size_t idx = 0; idx < tx.vout.size(); idx++) {
        const CTxOut& txOut = tx.vout[idx];
        CRecipient recipient = {txOut.scriptPubKey, txOut.nValue, setSubtractFeeFromOutputs.count(idx) == 1};
        vecSend.push_back(recipient);
    }

    coinControl->fAllowOtherInputs = true;
    coinControl->fOverrideFeeRate = overrideEstimatedFeeRate;

    for (const CTxIn& txin : tx.vin) {
        coinControl->Select(txin.prevout);
    }

    // Acquire the locks to prevent races to the new locked unspents between the
    // CreateTransaction call and LockCoin calls (when lockUnspents is true).
    LOCK2(cs_main, cs_wallet);

    CReserveKey reservekey(this);
    CWalletTx wtx;
    if (!CreateTransaction(vecSend, wtx, reservekey, nFeeRet, nChangePosInOut, strFailReason, coinControl, ALL_COINS, false, 0, 0, false)) {
        return false;
    }

    if (nChangePosInOut != -1) {
        tx.vout.insert(tx.vout.begin() + nChangePosInOut, wtx.vout[nChangePosInOut]);

        // Copy output sizes from new transaction; they may have had the fee subtracted from them
        for (unsigned int idx = 0; idx < tx.vout.size(); idx++)
            tx.vout[idx].nValue = wtx.vout[idx].nValue;

        // We don't have the normal Create/Commit cycle, and don't want to risk
        // reusing change, so just remove the key from the keypool here.
        reservekey.KeepKey();
    }

    // Copy output sizes from new transaction; they may have had the fee
    // subtracted from them.
    for (unsigned int idx = 0; idx < tx.vout.size(); idx++) {
        tx.vout[idx].nValue = wtx.vout[idx].nValue;
    }

    // Add new txins while keeping original txin scriptSig/order.
    for (const CTxIn& txin : wtx.vin) {
        if (!coinControl->IsSelected(txin.prevout.hash, txin.prevout.n)) {
            tx.vin.push_back(txin);

            if (lockUnspents) {
                LockCoin(txin.prevout);
            }
        }
    }