4 files changed, 179 insertions, 195 deletions

diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
index e1d0660627..c5cca0bff2 100644
--- a/src/qt/walletmodel.cpp
+++ b/src/qt/walletmodel.cpp
@@ -659,45 +659,39 @@ bool WalletModel::abandonTransaction(uint256 hash) const
 
 bool WalletModel::transactionCanBeBumped(uint256 hash) const
 {
-    LOCK2(cs_main, wallet->cs_wallet);
-    const CWalletTx *wtx = wallet->GetWalletTx(hash);
-    return wtx && SignalsOptInRBF(*(wtx->tx)) && !wtx->mapValue.count("replaced_by_txid");
+    return feebumper::TransactionCanBeBumped(wallet, hash);
 }
 
 bool WalletModel::bumpFee(uint256 hash)
 {
-    std::unique_ptr<CFeeBumper> feeBump;
-    {
-        CCoinControl coin_control;
-        coin_control.signalRbf = true;
-        LOCK2(cs_main, wallet->cs_wallet);
-        feeBump.reset(new CFeeBumper(wallet, hash, coin_control, 0));
-    }
-    if (feeBump->getResult() != BumpFeeResult::OK)
-    {
+    CCoinControl coin_control;
+    coin_control.signalRbf = true;
+    std::vector<std::string> errors;
+    CAmount old_fee;
+    CAmount new_fee;
+    CMutableTransaction mtx;
+    if (feebumper::CreateTransaction(wallet, hash, coin_control, 0 /* totalFee */, errors, old_fee, new_fee, mtx) != feebumper::Result::OK) {
         QMessageBox::critical(0, tr("Fee bump error"), tr("Increasing transaction fee failed") + "<br />(" +
-            (feeBump->getErrors().size() ? QString::fromStdString(feeBump->getErrors()[0]) : "") +")");
+            (errors.size() ? QString::fromStdString(errors[0]) : "") +")");
          return false;
     }
 
     // allow a user based fee verification
     QString questionString = tr("Do you want to increase the fee?");
     questionString.append("<br />");
-    CAmount oldFee = feeBump->getOldFee();
-    CAmount newFee = feeBump->getNewFee();
     questionString.append("<table style=\"text-align: left;\">");
     questionString.append("<tr><td>");
     questionString.append(tr("Current fee:"));
     questionString.append("</td><td>");
-    questionString.append(BitcoinUnits::formatHtmlWithUnit(getOptionsModel()->getDisplayUnit(), oldFee));
+    questionString.append(BitcoinUnits::formatHtmlWithUnit(getOptionsModel()->getDisplayUnit(), old_fee));
     questionString.append("</td></tr><tr><td>");
     questionString.append(tr("Increase:"));
     questionString.append("</td><td>");
-    questionString.append(BitcoinUnits::formatHtmlWithUnit(getOptionsModel()->getDisplayUnit(), newFee - oldFee));
+    questionString.append(BitcoinUnits::formatHtmlWithUnit(getOptionsModel()->getDisplayUnit(), new_fee - old_fee));
     questionString.append("</td></tr><tr><td>");
     questionString.append(tr("New fee:"));
     questionString.append("</td><td>");
-    questionString.append(BitcoinUnits::formatHtmlWithUnit(getOptionsModel()->getDisplayUnit(), newFee));
+    questionString.append(BitcoinUnits::formatHtmlWithUnit(getOptionsModel()->getDisplayUnit(), new_fee));
     questionString.append("</td></tr></table>");
     SendConfirmationDialog confirmationDialog(tr("Confirm fee bump"), questionString);
     confirmationDialog.exec();
@@ -715,23 +709,15 @@ bool WalletModel::bumpFee(uint256 hash)
     }
 
     // sign bumped transaction
-    bool res = false;
-    {
-        LOCK2(cs_main, wallet->cs_wallet);
-        res = feeBump->signTransaction(wallet);
-    }
-    if (!res) {
+    if (!feebumper::SignTransaction(wallet, mtx)) {
         QMessageBox::critical(0, tr("Fee bump error"), tr("Can't sign transaction."));
         return false;
     }
     // commit the bumped transaction
-    {
-        LOCK2(cs_main, wallet->cs_wallet);
-        res = feeBump->commit(wallet);
-    }
-    if(!res) {
+    uint256 txid;
+    if (feebumper::CommitTransaction(wallet, hash, std::move(mtx), errors, txid) != feebumper::Result::OK) {
         QMessageBox::critical(0, tr("Fee bump error"), tr("Could not commit transaction") + "<br />(" +
-            QString::fromStdString(feeBump->getErrors()[0])+")");
+            QString::fromStdString(errors[0])+")");
          return false;
     }
     return true;
diff --git a/src/wallet/feebumper.cpp b/src/wallet/feebumper.cpp
index 8b7c50b4e9..aaddd47de8 100644
--- a/src/wallet/feebumper.cpp
+++ b/src/wallet/feebumper.cpp
@@ -23,7 +23,7 @@
 // calculation, but we should be able to refactor after priority is removed).
 // NOTE: this requires that all inputs must be in mapWallet (eg the tx should
 // be IsAllFromMe).
-int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *pWallet)
+static int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet)
 {
     CMutableTransaction txNew(tx);
     std::vector<CInputCoin> vCoins;
@@ -31,11 +31,11 @@ int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *pWal
     // IsAllFromMe(ISMINE_SPENDABLE), so every input should already be in our
     // wallet, with a valid index into the vout array.
     for (auto& input : tx.vin) {
-        const auto mi = pWallet->mapWallet.find(input.prevout.hash);
-        assert(mi != pWallet->mapWallet.end() && input.prevout.n < mi->second.tx->vout.size());
+        const auto mi = wallet->mapWallet.find(input.prevout.hash);
+        assert(mi != wallet->mapWallet.end() && input.prevout.n < mi->second.tx->vout.size());
         vCoins.emplace_back(CInputCoin(&(mi->second), input.prevout.n));
     }
-    if (!pWallet->DummySignTx(txNew, vCoins)) {
+    if (!wallet->DummySignTx(txNew, vCoins)) {
         // This should never happen, because IsAllFromMe(ISMINE_SPENDABLE)
         // implies that we can sign for every input.
         return -1;
@@ -43,103 +43,102 @@ int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *pWal
     return GetVirtualTransactionSize(txNew);
 }
 
-bool CFeeBumper::preconditionChecks(const CWallet *pWallet, const CWalletTx& wtx) {
-    if (pWallet->HasWalletSpend(wtx.GetHash())) {
-        vErrors.push_back("Transaction has descendants in the wallet");
-        currentResult = BumpFeeResult::INVALID_PARAMETER;
-        return false;
+//! Check whether transaction has descendant in wallet or mempool, or has been
+//! mined, or conflicts with a mined transaction. Return a feebumper::Result.
+static feebumper::Result PreconditionChecks(const CWallet* wallet, const CWalletTx& wtx, std::vector<std::string>& errors)
+{
+    if (wallet->HasWalletSpend(wtx.GetHash())) {
+        errors.push_back("Transaction has descendants in the wallet");
+        return feebumper::Result::INVALID_PARAMETER;
     }
 
     {
         LOCK(mempool.cs);
         auto it_mp = mempool.mapTx.find(wtx.GetHash());
         if (it_mp != mempool.mapTx.end() && it_mp->GetCountWithDescendants() > 1) {
-            vErrors.push_back("Transaction has descendants in the mempool");
-            currentResult = BumpFeeResult::INVALID_PARAMETER;
-            return false;
+            errors.push_back("Transaction has descendants in the mempool");
+            return feebumper::Result::INVALID_PARAMETER;
         }
     }
 
     if (wtx.GetDepthInMainChain() != 0) {
-        vErrors.push_back("Transaction has been mined, or is conflicted with a mined transaction");
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return false;
+        errors.push_back("Transaction has been mined, or is conflicted with a mined transaction");
+        return feebumper::Result::WALLET_ERROR;
     }
-    return true;
+    return feebumper::Result::OK;
 }
 
-CFeeBumper::CFeeBumper(const CWallet *pWallet, const uint256 txidIn, const CCoinControl& coin_control, CAmount totalFee)
-    :
-    txid(std::move(txidIn)),
-    nOldFee(0),
-    nNewFee(0)
+namespace feebumper {
+
+bool TransactionCanBeBumped(CWallet* wallet, const uint256& txid)
 {
-    vErrors.clear();
-    bumpedTxid.SetNull();
-    AssertLockHeld(pWallet->cs_wallet);
-    auto it = pWallet->mapWallet.find(txid);
-    if (it == pWallet->mapWallet.end()) {
-        vErrors.push_back("Invalid or non-wallet transaction id");
-        currentResult = BumpFeeResult::INVALID_ADDRESS_OR_KEY;
-        return;
+    LOCK2(cs_main, wallet->cs_wallet);
+    const CWalletTx* wtx = wallet->GetWalletTx(txid);
+    return wtx && SignalsOptInRBF(*wtx->tx) && !wtx->mapValue.count("replaced_by_txid");
+}
+
+Result CreateTransaction(const CWallet* wallet, const uint256& txid, const CCoinControl& coin_control, CAmount total_fee, std::vector<std::string>& errors,
+                         CAmount& old_fee, CAmount& new_fee, CMutableTransaction& mtx)
+{
+    LOCK2(cs_main, wallet->cs_wallet);
+    errors.clear();
+    auto it = wallet->mapWallet.find(txid);
+    if (it == wallet->mapWallet.end()) {
+        errors.push_back("Invalid or non-wallet transaction id");
+        return Result::INVALID_ADDRESS_OR_KEY;
     }
     const CWalletTx& wtx = it->second;
 
-    if (!preconditionChecks(pWallet, wtx)) {
-        return;
+    Result result = PreconditionChecks(wallet, wtx, errors);
+    if (result != Result::OK) {
+        return result;
     }
 
     if (!SignalsOptInRBF(*wtx.tx)) {
-        vErrors.push_back("Transaction is not BIP 125 replaceable");
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return;
+        errors.push_back("Transaction is not BIP 125 replaceable");
+        return Result::WALLET_ERROR;
     }
 
     if (wtx.mapValue.count("replaced_by_txid")) {
-        vErrors.push_back(strprintf("Cannot bump transaction %s which was already bumped by transaction %s", txid.ToString(), wtx.mapValue.at("replaced_by_txid")));
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return;
+        errors.push_back(strprintf("Cannot bump transaction %s which was already bumped by transaction %s", txid.ToString(), wtx.mapValue.at("replaced_by_txid")));
+        return Result::WALLET_ERROR;
     }
 
     // check that original tx consists entirely of our inputs
     // if not, we can't bump the fee, because the wallet has no way of knowing the value of the other inputs (thus the fee)
-    if (!pWallet->IsAllFromMe(*wtx.tx, ISMINE_SPENDABLE)) {
-        vErrors.push_back("Transaction contains inputs that don't belong to this wallet");
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return;
+    if (!wallet->IsAllFromMe(*wtx.tx, ISMINE_SPENDABLE)) {
+        errors.push_back("Transaction contains inputs that don't belong to this wallet");
+        return Result::WALLET_ERROR;
     }
 
     // figure out which output was change
     // if there was no change output or multiple change outputs, fail
     int nOutput = -1;
     for (size_t i = 0; i < wtx.tx->vout.size(); ++i) {
-        if (pWallet->IsChange(wtx.tx->vout[i])) {
+        if (wallet->IsChange(wtx.tx->vout[i])) {
             if (nOutput != -1) {
-                vErrors.push_back("Transaction has multiple change outputs");
-                currentResult = BumpFeeResult::WALLET_ERROR;
-                return;
+                errors.push_back("Transaction has multiple change outputs");
+                return Result::WALLET_ERROR;
             }
             nOutput = i;
         }
     }
     if (nOutput == -1) {
-        vErrors.push_back("Transaction does not have a change output");
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return;
+        errors.push_back("Transaction does not have a change output");
+        return Result::WALLET_ERROR;
     }
 
     // Calculate the expected size of the new transaction.
     int64_t txSize = GetVirtualTransactionSize(*(wtx.tx));
-    const int64_t maxNewTxSize = CalculateMaximumSignedTxSize(*wtx.tx, pWallet);
+    const int64_t maxNewTxSize = CalculateMaximumSignedTxSize(*wtx.tx, wallet);
     if (maxNewTxSize < 0) {
-        vErrors.push_back("Transaction contains inputs that cannot be signed");
-        currentResult = BumpFeeResult::INVALID_ADDRESS_OR_KEY;
-        return;
+        errors.push_back("Transaction contains inputs that cannot be signed");
+        return Result::INVALID_ADDRESS_OR_KEY;
     }
 
     // calculate the old fee and fee-rate
-    nOldFee = wtx.GetDebit(ISMINE_SPENDABLE) - wtx.tx->GetValueOut();
-    CFeeRate nOldFeeRate(nOldFee, txSize);
+    old_fee = wtx.GetDebit(ISMINE_SPENDABLE) - wtx.tx->GetValueOut();
+    CFeeRate nOldFeeRate(old_fee, txSize);
     CFeeRate nNewFeeRate;
     // The wallet uses a conservative WALLET_INCREMENTAL_RELAY_FEE value to
     // future proof against changes to network wide policy for incremental relay
@@ -149,26 +148,24 @@ CFeeBumper::CFeeBumper(const CWallet *pWallet, const uint256 txidIn, const CCoin
         walletIncrementalRelayFee = ::incrementalRelayFee;
     }
 
-    if (totalFee > 0) {
+    if (total_fee > 0) {
         CAmount minTotalFee = nOldFeeRate.GetFee(maxNewTxSize) + ::incrementalRelayFee.GetFee(maxNewTxSize);
-        if (totalFee < minTotalFee) {
-            vErrors.push_back(strprintf("Insufficient totalFee, must be at least %s (oldFee %s + incrementalFee %s)",
+        if (total_fee < minTotalFee) {
+            errors.push_back(strprintf("Insufficient totalFee, must be at least %s (oldFee %s + incrementalFee %s)",
                                                                 FormatMoney(minTotalFee), FormatMoney(nOldFeeRate.GetFee(maxNewTxSize)), FormatMoney(::incrementalRelayFee.GetFee(maxNewTxSize))));
-            currentResult = BumpFeeResult::INVALID_PARAMETER;
-            return;
+            return Result::INVALID_PARAMETER;
         }
         CAmount requiredFee = GetRequiredFee(maxNewTxSize);
-        if (totalFee < requiredFee) {
-            vErrors.push_back(strprintf("Insufficient totalFee (cannot be less than required fee %s)",
+        if (total_fee < requiredFee) {
+            errors.push_back(strprintf("Insufficient totalFee (cannot be less than required fee %s)",
                                                                 FormatMoney(requiredFee)));
-            currentResult = BumpFeeResult::INVALID_PARAMETER;
-            return;
+            return Result::INVALID_PARAMETER;
         }
-        nNewFee = totalFee;
-        nNewFeeRate = CFeeRate(totalFee, maxNewTxSize);
+        new_fee = total_fee;
+        nNewFeeRate = CFeeRate(total_fee, maxNewTxSize);
     } else {
-        nNewFee = GetMinimumFee(maxNewTxSize, coin_control, mempool, ::feeEstimator, nullptr /* FeeCalculation */);
-        nNewFeeRate = CFeeRate(nNewFee, maxNewTxSize);
+        new_fee = GetMinimumFee(maxNewTxSize, coin_control, mempool, ::feeEstimator, nullptr /* FeeCalculation */);
+        nNewFeeRate = CFeeRate(new_fee, maxNewTxSize);
 
         // New fee rate must be at least old rate + minimum incremental relay rate
         // walletIncrementalRelayFee.GetFeePerK() should be exact, because it's initialized
@@ -177,53 +174,50 @@ CFeeBumper::CFeeBumper(const CWallet *pWallet, const uint256 txidIn, const CCoin
         // add 1 satoshi to the result, because it may have been rounded down.
         if (nNewFeeRate.GetFeePerK() < nOldFeeRate.GetFeePerK() + 1 + walletIncrementalRelayFee.GetFeePerK()) {
             nNewFeeRate = CFeeRate(nOldFeeRate.GetFeePerK() + 1 + walletIncrementalRelayFee.GetFeePerK());
-            nNewFee = nNewFeeRate.GetFee(maxNewTxSize);
+            new_fee = nNewFeeRate.GetFee(maxNewTxSize);
         }
     }
 
     // Check that in all cases the new fee doesn't violate maxTxFee
-     if (nNewFee > maxTxFee) {
-         vErrors.push_back(strprintf("Specified or calculated fee %s is too high (cannot be higher than maxTxFee %s)",
-                               FormatMoney(nNewFee), FormatMoney(maxTxFee)));
-         currentResult = BumpFeeResult::WALLET_ERROR;
-         return;
+     if (new_fee > maxTxFee) {
+         errors.push_back(strprintf("Specified or calculated fee %s is too high (cannot be higher than maxTxFee %s)",
+                               FormatMoney(new_fee), FormatMoney(maxTxFee)));
+         return Result::WALLET_ERROR;
      }
 
     // check that fee rate is higher than mempool's minimum fee
     // (no point in bumping fee if we know that the new tx won't be accepted to the mempool)
     // This may occur if the user set TotalFee or paytxfee too low, if fallbackfee is too low, or, perhaps,
     // in a rare situation where the mempool minimum fee increased significantly since the fee estimation just a
-    // moment earlier. In this case, we report an error to the user, who may use totalFee to make an adjustment.
+    // moment earlier. In this case, we report an error to the user, who may use total_fee to make an adjustment.
     CFeeRate minMempoolFeeRate = mempool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
     if (nNewFeeRate.GetFeePerK() < minMempoolFeeRate.GetFeePerK()) {
-        vErrors.push_back(strprintf(
+        errors.push_back(strprintf(
             "New fee rate (%s) is lower than the minimum fee rate (%s) to get into the mempool -- "
             "the totalFee value should be at least %s or the settxfee value should be at least %s to add transaction",
             FormatMoney(nNewFeeRate.GetFeePerK()),
             FormatMoney(minMempoolFeeRate.GetFeePerK()),
             FormatMoney(minMempoolFeeRate.GetFee(maxNewTxSize)),
             FormatMoney(minMempoolFeeRate.GetFeePerK())));
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return;
+        return Result::WALLET_ERROR;
     }
 
     // Now modify the output to increase the fee.
     // If the output is not large enough to pay the fee, fail.
-    CAmount nDelta = nNewFee - nOldFee;
+    CAmount nDelta = new_fee - old_fee;
     assert(nDelta > 0);
     mtx =  *wtx.tx;
     CTxOut* poutput = &(mtx.vout[nOutput]);
     if (poutput->nValue < nDelta) {
-        vErrors.push_back("Change output is too small to bump the fee");
-        currentResult = BumpFeeResult::WALLET_ERROR;
-        return;
+        errors.push_back("Change output is too small to bump the fee");
+        return Result::WALLET_ERROR;
     }
 
     // If the output would become dust, discard it (converting the dust to fee)
     poutput->nValue -= nDelta;
     if (poutput->nValue <= GetDustThreshold(*poutput, ::dustRelayFee)) {
         LogPrint(BCLog::RPC, "Bumping fee and discarding dust output\n");
-        nNewFee += poutput->nValue;
+        new_fee += poutput->nValue;
         mtx.vout.erase(mtx.vout.begin() + nOutput);
     }
 
@@ -234,36 +228,36 @@ CFeeBumper::CFeeBumper(const CWallet *pWallet, const uint256 txidIn, const CCoin
         }
     }
 
-    currentResult = BumpFeeResult::OK;
+    return Result::OK;
 }
 
-bool CFeeBumper::signTransaction(CWallet *pWallet)
-{
-     return pWallet->SignTransaction(mtx);
+bool SignTransaction(CWallet* wallet, CMutableTransaction& mtx) {
+    LOCK2(cs_main, wallet->cs_wallet);
+    return wallet->SignTransaction(mtx);
 }
 
-bool CFeeBumper::commit(CWallet *pWallet)
+Result CommitTransaction(CWallet* wallet, const uint256& txid, CMutableTransaction&& mtx, std::vector<std::string>& errors, uint256& bumped_txid)
 {
-    AssertLockHeld(pWallet->cs_wallet);
-    if (!vErrors.empty() || currentResult != BumpFeeResult::OK) {
-        return false;
+    LOCK2(cs_main, wallet->cs_wallet);
+    if (!errors.empty()) {
+        return Result::MISC_ERROR;
     }
-    auto it = txid.IsNull() ? pWallet->mapWallet.end() : pWallet->mapWallet.find(txid);
-    if (it == pWallet->mapWallet.end()) {
-        vErrors.push_back("Invalid or non-wallet transaction id");
-        currentResult = BumpFeeResult::MISC_ERROR;
-        return false;
+    auto it = txid.IsNull() ? wallet->mapWallet.end() : wallet->mapWallet.find(txid);
+    if (it == wallet->mapWallet.end()) {
+        errors.push_back("Invalid or non-wallet transaction id");
+        return Result::MISC_ERROR;
     }
     CWalletTx& oldWtx = it->second;
 
     // make sure the transaction still has no descendants and hasn't been mined in the meantime
-    if (!preconditionChecks(pWallet, oldWtx)) {
-        return false;
+    Result result = PreconditionChecks(wallet, oldWtx, errors);
+    if (result != Result::OK) {
+        return result;
     }
 
-    CWalletTx wtxBumped(pWallet, MakeTransactionRef(std::move(mtx)));
+    CWalletTx wtxBumped(wallet, MakeTransactionRef(std::move(mtx)));
     // commit/broadcast the tx
-    CReserveKey reservekey(pWallet);
+    CReserveKey reservekey(wallet);
     wtxBumped.mapValue = oldWtx.mapValue;
     wtxBumped.mapValue["replaces_txid"] = oldWtx.GetHash().ToString();
     wtxBumped.vOrderForm = oldWtx.vOrderForm;
@@ -271,27 +265,29 @@ bool CFeeBumper::commit(CWallet *pWallet)
     wtxBumped.fTimeReceivedIsTxTime = true;
     wtxBumped.fFromMe = true;
     CValidationState state;
-    if (!pWallet->CommitTransaction(wtxBumped, reservekey, g_connman.get(), state)) {
+    if (!wallet->CommitTransaction(wtxBumped, reservekey, g_connman.get(), state)) {
         // NOTE: CommitTransaction never returns false, so this should never happen.
-        vErrors.push_back(strprintf("The transaction was rejected: %s", state.GetRejectReason()));
-        return false;
+        errors.push_back(strprintf("The transaction was rejected: %s", state.GetRejectReason()));
+        return Result::WALLET_ERROR;
     }
 
-    bumpedTxid = wtxBumped.GetHash();
+    bumped_txid = wtxBumped.GetHash();
     if (state.IsInvalid()) {
         // This can happen if the mempool rejected the transaction.  Report
         // what happened in the "errors" response.
-        vErrors.push_back(strprintf("The transaction was rejected: %s", FormatStateMessage(state)));
+        errors.push_back(strprintf("Error: The transaction was rejected: %s", FormatStateMessage(state)));
     }
 
     // mark the original tx as bumped
-    if (!pWallet->MarkReplaced(oldWtx.GetHash(), wtxBumped.GetHash())) {
+    if (!wallet->MarkReplaced(oldWtx.GetHash(), wtxBumped.GetHash())) {
         // TODO: see if JSON-RPC has a standard way of returning a response
         // along with an exception. It would be good to return information about
         // wtxBumped to the caller even if marking the original transaction
         // replaced does not succeed for some reason.
-        vErrors.push_back("Created new bumpfee transaction but could not mark the original transaction as replaced");
+        errors.push_back("Created new bumpfee transaction but could not mark the original transaction as replaced");
     }
-    return true;
+    return Result::OK;
 }
 
+} // namespace feebumper
+
diff --git a/src/wallet/feebumper.h b/src/wallet/feebumper.h
index 3d64e53c15..8eec30440c 100644
--- a/src/wallet/feebumper.h
+++ b/src/wallet/feebumper.h
@@ -13,7 +13,9 @@ class uint256;
 class CCoinControl;
 enum class FeeEstimateMode;
 
-enum class BumpFeeResult
+namespace feebumper {
+
+enum class Result
 {
     OK,
     INVALID_ADDRESS_OR_KEY,
@@ -23,39 +25,34 @@ enum class BumpFeeResult
     MISC_ERROR,
 };
 
-class CFeeBumper
-{
-public:
-    CFeeBumper(const CWallet *pWalletIn, const uint256 txidIn, const CCoinControl& coin_control, CAmount totalFee);
-    BumpFeeResult getResult() const { return currentResult; }
-    const std::vector<std::string>& getErrors() const { return vErrors; }
-    CAmount getOldFee() const { return nOldFee; }
-    CAmount getNewFee() const { return nNewFee; }
-    uint256 getBumpedTxId() const { return bumpedTxid; }
-
-    /* signs the new transaction,
-     * returns false if the tx couldn't be found or if it was
-     * impossible to create the signature(s)
-     */
-    bool signTransaction(CWallet *pWallet);
-
-    /* commits the fee bump,
-     * returns true, in case of CWallet::CommitTransaction was successful
-     * but, eventually sets vErrors if the tx could not be added to the mempool (will try later)
-     * or if the old transaction could not be marked as replaced
-     */
-    bool commit(CWallet *pWalletNonConst);
-
-private:
-    bool preconditionChecks(const CWallet *pWallet, const CWalletTx& wtx);
-
-    const uint256 txid;
-    uint256 bumpedTxid;
-    CMutableTransaction mtx;
-    std::vector<std::string> vErrors;
-    BumpFeeResult currentResult;
-    CAmount nOldFee;
-    CAmount nNewFee;
-};
+//! Return whether transaction can be bumped.
+bool TransactionCanBeBumped(CWallet* wallet, const uint256& txid);
+
+//! Create bumpfee transaction.
+Result CreateTransaction(const CWallet* wallet,
+                         const uint256& txid,
+                         const CCoinControl& coin_control,
+                         CAmount total_fee,
+                         std::vector<std::string>& errors,
+                         CAmount& old_fee,
+                         CAmount& new_fee,
+                         CMutableTransaction& mtx);
+
+//! Sign the new transaction,
+//! @return false if the tx couldn't be found or if it was
+//! impossible to create the signature(s)
+bool SignTransaction(CWallet* wallet, CMutableTransaction& mtx);
+
+//! Commit the bumpfee transaction.
+//! @return success in case of CWallet::CommitTransaction was successful,
+//! but sets errors if the tx could not be added to the mempool (will try later)
+//! or if the old transaction could not be marked as replaced.
+Result CommitTransaction(CWallet* wallet,
+                         const uint256& txid,
+                         CMutableTransaction&& mtx,
+                         std::vector<std::string>& errors,
+                         uint256& bumped_txid);
+
+} // namespace feebumper
 
 #endif // BITCOIN_WALLET_FEEBUMPER_H
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index cba0538e7e..b081803be6 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3224,45 +3224,50 @@ UniValue bumpfee(const JSONRPCRequest& request)
     LOCK2(cs_main, pwallet->cs_wallet);
     EnsureWalletIsUnlocked(pwallet);
 
-    CFeeBumper feeBump(pwallet, hash, coin_control, totalFee);
-    BumpFeeResult res = feeBump.getResult();
-    if (res != BumpFeeResult::OK)
-    {
+
+    std::vector<std::string> errors;
+    CAmount old_fee;
+    CAmount new_fee;
+    CMutableTransaction mtx;
+    feebumper::Result res = feebumper::CreateTransaction(pwallet, hash, coin_control, totalFee, errors, old_fee, new_fee, mtx);
+    if (res != feebumper::Result::OK) {
         switch(res) {
-            case BumpFeeResult::INVALID_ADDRESS_OR_KEY:
-                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, feeBump.getErrors()[0]);
+            case feebumper::Result::INVALID_ADDRESS_OR_KEY:
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, errors[0]);
                 break;
-            case BumpFeeResult::INVALID_REQUEST:
-                throw JSONRPCError(RPC_INVALID_REQUEST, feeBump.getErrors()[0]);
+            case feebumper::Result::INVALID_REQUEST:
+                throw JSONRPCError(RPC_INVALID_REQUEST, errors[0]);
                 break;
-            case BumpFeeResult::INVALID_PARAMETER:
-                throw JSONRPCError(RPC_INVALID_PARAMETER, feeBump.getErrors()[0]);
+            case feebumper::Result::INVALID_PARAMETER:
+                throw JSONRPCError(RPC_INVALID_PARAMETER, errors[0]);
                 break;
-            case BumpFeeResult::WALLET_ERROR:
-                throw JSONRPCError(RPC_WALLET_ERROR, feeBump.getErrors()[0]);
+            case feebumper::Result::WALLET_ERROR:
+                throw JSONRPCError(RPC_WALLET_ERROR, errors[0]);
                 break;
             default:
-                throw JSONRPCError(RPC_MISC_ERROR, feeBump.getErrors()[0]);
+                throw JSONRPCError(RPC_MISC_ERROR, errors[0]);
                 break;
         }
     }
 
     // sign bumped transaction
-    if (!feeBump.signTransaction(pwallet)) {
+    if (!feebumper::SignTransaction(pwallet, mtx)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Can't sign transaction.");
     }
     // commit the bumped transaction
-    if(!feeBump.commit(pwallet)) {
-        throw JSONRPCError(RPC_WALLET_ERROR, feeBump.getErrors()[0]);
+    uint256 txid;
+    if (feebumper::CommitTransaction(pwallet, hash, std::move(mtx), errors, txid) != feebumper::Result::OK) {
+        throw JSONRPCError(RPC_WALLET_ERROR, errors[0]);
     }
     UniValue result(UniValue::VOBJ);
-    result.push_back(Pair("txid", feeBump.getBumpedTxId().GetHex()));
-    result.push_back(Pair("origfee", ValueFromAmount(feeBump.getOldFee())));
-    result.push_back(Pair("fee", ValueFromAmount(feeBump.getNewFee())));
-    UniValue errors(UniValue::VARR);
-    for (const std::string& err: feeBump.getErrors())
-        errors.push_back(err);
-    result.push_back(Pair("errors", errors));
+    result.push_back(Pair("txid", txid.GetHex()));
+    result.push_back(Pair("origfee", ValueFromAmount(old_fee)));
+    result.push_back(Pair("fee", ValueFromAmount(new_fee)));
+    UniValue result_errors(UniValue::VARR);
+    for (const std::string& error : errors) {
+        result_errors.push_back(error);
+    }
+    result.push_back(Pair("errors", result_errors));
 
     return result;
 }