Codechange: Extract code to build cargo acceptance string for re-use.

src/cargotype.cpp

@@ -19,6 +19,8 @@
 #include "table/strings.h"
 #include "table/cargo_const.h"
 
+#include <sstream>
+
 #include "safeguards.h"
 
 CargoSpec CargoSpec::array[NUM_CARGO];
@@ -257,3 +259,39 @@ uint64_t CargoSpec::WeightOfNUnitsInTrain(uint32_t n) const
 	if (this->is_freight) n *= _settings_game.vehicle.freight_trains;
 	return this->WeightOfNUnits(n);
 }
+
+/**
+ * Build comma-separated cargo acceptance string.
+ * @param acceptance CargoArray filled with accepted cargo.
+ * @param label Label to prefix cargo acceptance list.
+ * @return String of accepted cargo, or nullopt if no cargo is accepted.
+ */
+std::optional<std::string> BuildCargoAcceptanceString(const CargoArray &acceptance, StringID label)
+{
+	/* Cargo acceptance is displayed in a extra multiline */
+	std::stringstream line;
+	line << GetString(label);
+
+	bool found = false;
+	for (const CargoSpec *cs : _sorted_cargo_specs) {
+		CargoID cid = cs->Index();
+		if (acceptance[cid] > 0) {
+			/* Add a comma between each item. */
+			if (found) line << ", ";
+			found = true;
+
+			/* If the accepted value is less than 8, show it in 1/8:ths */
+			if (acceptance[cid] < 8) {
+				SetDParam(0, acceptance[cid]);
+				SetDParam(1, cs->name);
+				line << GetString(STR_LAND_AREA_INFORMATION_CARGO_EIGHTS);
+			} else {
+				line << GetString(cs->name);
+			}
+		}
+	}
+
+	if (found) return line.str();
+
+	return std::nullopt;
+}

src/cargotype.h

@@ -214,6 +214,8 @@ void SetupCargoForClimate(LandscapeID l);
 bool IsDefaultCargo(CargoID cid);
 void BuildCargoLabelMap();
 
+std::optional<std::string> BuildCargoAcceptanceString(const CargoArray &acceptance, StringID label);
+
 inline CargoID GetCargoIDByLabel(CargoLabel label)
 {
 	auto found = CargoSpec::label_map.find(label);

src/misc_gui.cpp

@@ -307,29 +307,9 @@ public:
 		}
 
 		/* Cargo acceptance is displayed in a extra multiline */
-		std::stringstream line;
+		auto line = BuildCargoAcceptanceString(acceptance, STR_LAND_AREA_INFORMATION_CARGO_ACCEPTED);
-		line << GetString(STR_LAND_AREA_INFORMATION_CARGO_ACCEPTED);
+		if (line.has_value()) {
-
+			this->cargo_acceptance = std::move(*line);
-		bool found = false;
-		for (const CargoSpec *cs : _sorted_cargo_specs) {
-			CargoID cid = cs->Index();
-			if (acceptance[cid] > 0) {
-				/* Add a comma between each item. */
-				if (found) line << ", ";
-				found = true;
-
-				/* If the accepted value is less than 8, show it in 1/8:ths */
-				if (acceptance[cid] < 8) {
-					SetDParam(0, acceptance[cid]);
-					SetDParam(1, cs->name);
-					line << GetString(STR_LAND_AREA_INFORMATION_CARGO_EIGHTS);
-				} else {
-					line << GetString(cs->name);
-				}
-			}
-		}
-		if (found) {
-			this->cargo_acceptance = line.str();
 		} else {
 			this->cargo_acceptance.clear();
 		}