scope nested component props without deep copies

src/lib/dvalue.h

@@ -12,11 +12,11 @@ struct DValue {
 	char type = 'S';
 
 	String 	_String;
-	f64 	_float;
+	f64 	_float = 0;
 	s64 	_array_index = 0;
-	bool	_bool;
+	bool	_bool = false;
 	bool	_list_mode = false;
-	void*	_ptr;
+	void*	_ptr = 0;
 	std::map<String, DValue> _map;
 
 	// Read accessors are const and never create or modify nodes. The to_*

src/wasm/core.cpp

@@ -494,20 +494,32 @@ struct RequestPropsScope
 	Request* context = 0;
 	DValue previous_props;
 
-	RequestPropsScope(Request* context, const DValue& props)
+	static void swap_value(DValue& left, DValue& right)
+	{
+		std::swap(left.type, right.type);
+		left._String.swap(right._String);
+		std::swap(left._float, right._float);
+		std::swap(left._array_index, right._array_index);
+		std::swap(left._bool, right._bool);
+		std::swap(left._list_mode, right._list_mode);
+		std::swap(left._ptr, right._ptr);
+		left._map.swap(right._map);
+	}
+
+	RequestPropsScope(Request* context, DValue& props)
 	{
 		this->context = context;
 		if(this->context)
 		{
-			previous_props = this->context->props;
-			this->context->props = props;
+			swap_value(previous_props, this->context->props);
+			swap_value(this->context->props, props);
 		}
 	}
 
 	~RequestPropsScope()
 	{
 		if(context)
-			context->props = previous_props;
+			swap_value(context->props, previous_props);
 	}
 };
 
@@ -600,7 +612,8 @@ DValue* unit_call(String file_name, String function_name, DValue* call_param)
 			print("Error: unit_call() function '", function_name, "' not found");
 			return(0);
 		}
-		RequestPropsScope props_scope(context, (call_param ? *call_param : DValue()));
+		DValue props = call_param ? *call_param : DValue();
+		RequestPropsScope props_scope(context, props);
 		if((handler == "render" || handler.rfind("render:", 0) == 0 || handler == "component" || handler.rfind("component:", 0) == 0) && resolved != "")
 			wasm_run_once(resolved, *context);
 		String previous_unit = context->resources.current_unit_file;
@@ -634,7 +647,7 @@ DValue* unit_call(String file_name, String function_name, DValue* call_param)
 	return(0);
 }
 
-void component_render(String name, DValue props, Request& request)
+static void component_render_with_props(String name, DValue& props, Request& request)
 {
 	String file_name, render_name;
 	component_parse_target(trim(name), file_name, render_name);
@@ -658,14 +671,15 @@ void component_render(String name, DValue props, Request& request)
 	request.resources.current_unit_file = previous_unit;
 }
 
-void component_render(String name) { DValue props; component_render(name, props, *context); }
-void component_render(String name, Request& request) { DValue props; component_render(name, props, request); }
-void component_render(String name, DValue props) { component_render(name, props, *context); }
+void component_render(String name, DValue props, Request& request) { component_render_with_props(name, props, request); }
+void component_render(String name) { DValue props; component_render_with_props(name, props, *context); }
+void component_render(String name, Request& request) { DValue props; component_render_with_props(name, props, request); }
+void component_render(String name, DValue props) { component_render_with_props(name, props, *context); }
 
 String component(String name, DValue props, Request& request)
 {
 	ob_start();
-	component_render(name, props, request);
+	component_render_with_props(name, props, request);
 	return(ob_get_close());
 }