wallet: Use std::optional for GetExternalOutput and fixups

Author: aureleoules

src/wallet/coincontrol.h

@@ -13,9 +13,9 @@
 #include <script/signingprovider.h>
 #include <script/standard.h>
 
-#include <optional>
 #include <algorithm>
 #include <map>
+#include <optional>
 #include <set>
 
 namespace wallet {
@@ -65,27 +65,27 @@ class CCoinControl
 
     bool HasSelected() const
     {
-        return (m_selected_inputs.size() > 0);
+        return !m_selected_inputs.empty();
     }
 
     bool IsSelected(const COutPoint& output) const
     {
-        return (m_selected_inputs.count(output) > 0);
+        return m_selected_inputs.count(output) > 0;
     }
 
     bool IsExternalSelected(const COutPoint& output) const
     {
-        return (m_external_txouts.count(output) > 0);
+        return m_external_txouts.count(output) > 0;
     }
 
-    bool GetExternalOutput(const COutPoint& outpoint, CTxOut& txout) const
+    std::optional<CTxOut> GetExternalOutput(const COutPoint& outpoint) const
     {
         const auto ext_it = m_external_txouts.find(outpoint);
         if (ext_it == m_external_txouts.end()) {
-            return false;
+            return std::nullopt;
         }
-        txout = ext_it->second;
-        return true;
+
+        return std::make_optional(ext_it->second);
     }
 
     void Select(const COutPoint& output)

src/wallet/spend.cpp

@@ -52,9 +52,7 @@ int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* wallet,
 TxSize CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts, const CCoinControl* coin_control)
 {
     CMutableTransaction txNew(tx);
-    if (!wallet->DummySignTx(txNew, txouts, coin_control)) {
-        return TxSize{-1, -1};
-    }
+    if (!wallet->DummySignTx(txNew, txouts, coin_control)) return TxSize{-1, -1};
     CTransaction ctx(txNew);
     int64_t vsize = GetVirtualTransactionSize(ctx);
     int64_t weight = GetTransactionWeight(ctx);
@@ -72,11 +70,9 @@ TxSize CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *walle
             assert(input.prevout.n < mi->second.tx->vout.size());
             txouts.emplace_back(mi->second.tx->vout.at(input.prevout.n));
         } else if (coin_control) {
-            CTxOut txout;
-            if (!coin_control->GetExternalOutput(input.prevout, txout)) {
-                return TxSize{-1, -1};
-            }
-            txouts.emplace_back(txout);
+            const auto& txout{coin_control->GetExternalOutput(input.prevout)};
+            if (!txout) return TxSize{-1, -1};
+            txouts.emplace_back(*txout);
         } else {
             return TxSize{-1, -1};
         }
@@ -178,9 +174,12 @@ util::Result<PreSelectedInputs> FetchSelectedInputs(const CWallet& wallet, const
             input_bytes = CalculateMaximumSignedInputSize(txout, &wallet, &coin_control);
         } else {
             // The input is external. We did not find the tx in mapWallet.
-            if (!coin_control.GetExternalOutput(outpoint, txout)) {
+            const auto out{coin_control.GetExternalOutput(outpoint)};
+            if (!out) {
                 return util::Error{strprintf(_("Not found pre-selected input %s"), outpoint.ToString())};
             }
+
+            txout = *out;
         }
 
         if (input_bytes == -1) {