Use CommandContainer for demolish area callback state storage

src/misc_gui.cpp

@@ -12,8 +12,6 @@
 #include "landscape.h"
 #include "error.h"
 #include "gui.h"
-
-#include <utility>
 #include "command_func.h"
 #include "company_func.h"
 #include "town.h"
@@ -1232,19 +1230,19 @@ void ShowQueryString(StringID str, StringID caption, uint maxsize, Window *paren
  * Window used for asking the user a YES/NO question.
  */
 struct QueryWindow : public Window {
-	QueryCallbackProc proc;  ///< callback function executed on closing of popup. Window* points to parent, bool is true if 'yes' clicked, false otherwise
+	QueryCallbackProc *proc; ///< callback function executed on closing of popup. Window* points to parent, bool is true if 'yes' clicked, false otherwise
 	uint64 params[10];       ///< local copy of #_global_string_params
 	StringID message;        ///< message shown for query window
 	StringID caption;        ///< title of window
 
-	QueryWindow(WindowDesc *desc, StringID caption, StringID message, Window *parent, QueryCallbackProc callback) : Window(desc)
+	QueryWindow(WindowDesc *desc, StringID caption, StringID message, Window *parent, QueryCallbackProc *callback) : Window(desc)
 	{
 		/* Create a backup of the variadic arguments to strings because it will be
 		 * overridden pretty often. We will copy these back for drawing */
 		CopyOutDParam(this->params, 0, lengthof(this->params));
 		this->caption = caption;
 		this->message = message;
-		this->proc    = std::move(callback);
+		this->proc    = callback;
 		this->parent  = parent;
 
 		this->InitNested(WN_CONFIRM_POPUP_QUERY);
@@ -1301,7 +1299,7 @@ struct QueryWindow : public Window {
 			case WID_Q_YES: {
 				/* in the Generate New World window, clicking 'Yes' causes
 				 * DeleteNonVitalWindows() to be called - we shouldn't be in a window then */
-				QueryCallbackProc proc = this->proc;
+				QueryCallbackProc *proc = this->proc;
 				Window *parent = this->parent;
 				/* Prevent the destructor calling the callback function */
 				this->proc = nullptr;
@@ -1366,9 +1364,9 @@ static WindowDesc _query_desc(
  * @param message string that will be shown for the window
  * @param parent pointer to parent window, if this pointer is nullptr the parent becomes
  * the main window WC_MAIN_WINDOW
- * @param callback callback function to set in the window descriptor
+ * @param callback callback function pointer to set in the window descriptor
  */
-void ShowQuery(StringID caption, StringID message, Window *parent, QueryCallbackProc callback)
+void ShowQuery(StringID caption, StringID message, Window *parent, QueryCallbackProc *callback)
 {
 	if (parent == nullptr) parent = FindWindowById(WC_MAIN_WINDOW, 0);
 
@@ -1376,7 +1374,7 @@ void ShowQuery(StringID caption, StringID message, Window *parent, QueryCallback
 		if (w->window_class != WC_CONFIRM_POPUP_QUERY) continue;
 
 		const QueryWindow *qw = (const QueryWindow *)w;
-		if (qw->parent != parent) continue;
+		if (qw->parent != parent || qw->proc != callback) continue;
 
 		delete qw;
 		break;

src/network/network_gui.cpp

@@ -2141,7 +2141,7 @@ public:
 
 			case WID_CL_MATRIX: {
 				StringID text = STR_NULL;
-				QueryCallbackProc callback = nullptr;
+				QueryCallbackProc *callback = nullptr;
 
 				switch (index) {
 					case DD_CLIENT_ADMIN_KICK:

src/terraform_gui.cpp

@@ -120,6 +120,14 @@ static bool IsIndustryOrRailStationInArea(TileIndex start_tile, TileIndex end_ti
 	return destroying_industry_or_station;
 }
 
+static CommandContainer _demolish_area_command;
+
+static void DemolishAreaConfirmationCallback(Window*, bool confirmed) {
+	if (confirmed) {
+		DoCommandP(&_demolish_area_command);
+	}
+}
+
 /**
  * A central place to handle all X_AND_Y dragged GUI functions.
  * @param proc       Procedure related to the dragging
@@ -140,20 +148,13 @@ bool GUIPlaceProcDragXY(ViewportDragDropSelectionProcess proc, TileIndex start_t
 
 	switch (proc) {
 		case DDSP_DEMOLISH_AREA: {
-			const bool should_query_first = IsIndustryOrRailStationInArea(start_tile, end_tile, _ctrl_pressed);
+			_demolish_area_command = NewCommandContainerBasic(end_tile, start_tile, _ctrl_pressed ? 1 : 0, CMD_CLEAR_AREA | CMD_MSG(STR_ERROR_CAN_T_CLEAR_THIS_AREA), CcPlaySound_EXPLOSION);
 
-			const auto cmd_clear_area = [=](Window*, bool confirmed) {
-				if (confirmed) {
-					DoCommandP(end_tile, start_tile, _ctrl_pressed ? 1 : 0, CMD_CLEAR_AREA | CMD_MSG(STR_ERROR_CAN_T_CLEAR_THIS_AREA), CcPlaySound_EXPLOSION);
-				}
-			};
-
-			if (should_query_first) {
-				ShowQuery(STR_QUERY_CLEAR_AREA_CAPTION, STR_CLEAR_AREA_CONFIRMATION_TEXT, nullptr, cmd_clear_area);
+			if (IsIndustryOrRailStationInArea(start_tile, end_tile, _ctrl_pressed)) {
+				ShowQuery(STR_QUERY_CLEAR_AREA_CAPTION, STR_CLEAR_AREA_CONFIRMATION_TEXT, nullptr, DemolishAreaConfirmationCallback);
 			} else {
-				cmd_clear_area(nullptr, true);
+				DemolishAreaConfirmationCallback(nullptr, true);
 			}
-
 			break;
 		}
 		case DDSP_RAISE_AND_LEVEL_AREA:

src/textbuf_gui.h

@@ -10,13 +10,10 @@
 #ifndef TEXTBUF_GUI_H
 #define TEXTBUF_GUI_H
 
+#include "window_type.h"
 #include "string_type.h"
 #include "strings_type.h"
 
-#include <functional>
-
-struct Window;
-
 /** Flags used in ShowQueryString() call */
 enum QueryStringFlags {
 	QSF_NONE             =    0,
@@ -29,10 +26,10 @@ enum QueryStringFlags {
 DECLARE_ENUM_AS_BIT_SET(QueryStringFlags)
 
 /** Callback procedure for the ShowQuery method. */
-typedef std::function<void(Window*, bool)> QueryCallbackProc;
+typedef void QueryCallbackProc(Window*, bool);
 
 void ShowQueryString(StringID str, StringID caption, uint max_len, Window *parent, CharSetFilter afilter, QueryStringFlags flags);
-void ShowQuery(StringID caption, StringID message, Window *w, QueryCallbackProc callback);
+void ShowQuery(StringID caption, StringID message, Window *w, QueryCallbackProc *callback);
 
 /** The number of 'characters' on the on-screen keyboard. */
 static const uint OSK_KEYBOARD_ENTRIES = 50;