privatesend: Fix countPossibleOutputs

xdustinface · xdustinface · commit 05ee734f69ea · 2020-08-14T16:54:57.000+02:00
- Fix off by one issue
- Respect max outputs threshold
diff --git a/src/privatesend/privatesend-client.cpp b/src/privatesend/privatesend-client.cpp
@@ -1650,10 +1650,17 @@ bool CPrivateSendClientSession::CreateDenominated(CAmount nBalanceToDenominate,
 
         auto countPossibleOutputs = [&](CAmount nAmount) -> int {
             std::vector<CAmount> vecOutputs;
-            while (txBuilder.TryAddOutputs(vecOutputs)) {
+            while(true) {
+                // Create an potential output
                 vecOutputs.push_back(nAmount);
+                if (!txBuilder.TryAddOutputs(vecOutputs) || txBuilder.CountOutputs() + vecOutputs.size() >= PRIVATESEND_DENOM_OUTPUTS_THRESHOLD) {
+                    // If its not possible to add it due to insufficient amount left or total number of outputs exceeds
+                    // PRIVATESEND_DENOM_OUTPUTS_THRESHOLD drop the output again and stop trying.
+                    vecOutputs.pop_back();
+                    break;
+                }
             }
-            return vecOutputs.size();
+            return static_cast<int>(vecOutputs.size());
         };
 
         // Go big to small
