Add: AppendStringInPlace() to append translated string ID into an existing string. (#12969)

This allows avoiding a string copy when building strings.

src/depot_gui.cpp

@@ -896,7 +896,7 @@ struct DepotWindow : Window {
 			SetDParam(1, loaded[cargo_type]);   // {CARGO} #2
 			SetDParam(2, cargo_type);           // {SHORTCARGO} #1
 			SetDParam(3, capacity[cargo_type]); // {SHORTCARGO} #2
-			details += GetString(STR_DEPOT_VEHICLE_TOOLTIP_CARGO);
+			AppendStringInPlace(details, STR_DEPOT_VEHICLE_TOOLTIP_CARGO);
 		}
 
 		/* Show tooltip window */

src/error_gui.cpp

@@ -394,11 +394,11 @@ void ShowErrorMessage(StringID summary_msg, StringID detailed_msg, WarningLevel
 		std::string message = GetString(summary_msg);
 		if (detailed_msg != INVALID_STRING_ID) {
 			message += " ";
-			message += GetString(detailed_msg);
+			AppendStringInPlace(message, detailed_msg);
 		}
 		if (extra_msg != INVALID_STRING_ID) {
 			message += " ";
-			message += GetString(extra_msg);
+			AppendStringInPlace(message, extra_msg);
 		}
 
 		if (textref_stack_size > 0) StopTextRefStackUsage();

src/industry_gui.cpp

@@ -386,7 +386,7 @@ class BuildIndustryWindow : public Window {
 			}
 			SetDParam(0, CargoSpec::Get(cargolist[j])->name);
 			SetDParamStr(1, cargo_suffix[j].text);
-			cargostring += GetString(STR_INDUSTRY_VIEW_CARGO_LIST_EXTENSION);
+			AppendStringInPlace(cargostring, STR_INDUSTRY_VIEW_CARGO_LIST_EXTENSION);
 		}
 
 		if (numcargo > 0) {

src/linkgraph/linkgraph_gui.cpp

@@ -394,7 +394,7 @@ bool LinkGraphOverlay::ShowTooltip(Point pt, TooltipCloseCondition close_cond)
 				const auto time = link.time ? back_time ? ((link.time + back_time) / 2) : link.time : back_time;
 				if (time > 0) {
 					SetDParam(0, time);
-					tooltip_extension += GetString(STR_LINKGRAPH_STATS_TOOLTIP_TIME_EXTENSION);
+					AppendStringInPlace(tooltip_extension, STR_LINKGRAPH_STATS_TOOLTIP_TIME_EXTENSION);
 				}
 				SetDParam(0, link.cargo);
 				SetDParam(1, link.Usage());

src/roadveh_gui.cpp

@@ -60,10 +60,10 @@ void DrawRoadVehDetails(const Vehicle *v, const Rect &r)
 
 				SetDParam(0, cid);
 				SetDParam(1, max_cargo[cid]);
-				capacity += GetString(STR_JUST_CARGO);
+				AppendStringInPlace(capacity, STR_JUST_CARGO);
 
 				if (subtype_text[cid] != STR_NULL) {
-					capacity += GetString(subtype_text[cid]);
+					AppendStringInPlace(capacity, subtype_text[cid]);
 				}
 
 				first = false;

src/strings.cpp

@@ -322,6 +322,19 @@ std::string GetString(StringID string)
 	return GetStringWithArgs(string, _global_string_params);
 }
 
+/**
+ * Resolve the given StringID and append in place into an existing std::string with all the associated
+ * DParam lookups and formatting.
+ * @param result The std::string to place the translated string.
+ * @param string The unique identifier of the translatable string.
+ */
+void AppendStringInPlace(std::string &result, StringID string)
+{
+	_global_string_params.PrepareForNextRun();
+	StringBuilder builder(result);
+	GetStringWithArgs(builder, string, _global_string_params);
+}
+
 /**
  * Get a parsed string with most special stringcodes replaced by the string parameters.
  * @param string The ID of the string to parse.

src/strings_func.h

@@ -61,6 +61,7 @@ inline StringID MakeStringID(StringTab tab, uint index)
 
 std::string GetString(StringID string);
 const char *GetStringPtr(StringID string);
+void AppendStringInPlace(std::string &result, StringID string);
 
 uint ConvertKmhishSpeedToDisplaySpeed(uint speed, VehicleType type);
 uint ConvertDisplaySpeedToKmhishSpeed(uint speed, VehicleType type);