Since dragging a ModuleWidget can move all modules, push a ComplexAction of ModuleMove actions instead of a single action.

include/app/RackWidget.hpp

@@ -6,6 +6,8 @@
 #include "app/CableWidget.hpp"
 #include "app/PortWidget.hpp"
 #include "app/ParamWidget.hpp"
+#include "history.hpp"
+#include <map>
 
 
 namespace rack {
@@ -21,6 +23,7 @@ struct RackWidget : widget::OpaqueWidget {
 	/** The last mouse position in the RackWidget */
 	math::Vec mousePos;
 	ParamWidget *touchedParam = NULL;
+	std::map<int, math::Vec> moduleDragPositions;
 
 	RackWidget();
 	~RackWidget();
@@ -55,6 +58,8 @@ struct RackWidget : widget::OpaqueWidget {
 	void setModulePosForce(ModuleWidget *mw, math::Vec pos);
 	ModuleWidget *getModule(int moduleId);
 	bool isEmpty();
+	void updateModuleDragPositions();
+	history::ComplexAction *getModuleDragAction();
 
 	// Cable methods
 

include/history.hpp

@@ -53,6 +53,7 @@ struct ComplexAction : Action {
 	void undo() override;
 	void redo() override;
 	void push(Action *action);
+	bool isEmpty();
 };
 
 

src/app/ModuleWidget.cpp

@@ -386,17 +386,16 @@ void ModuleWidget::onDragStart(const event::DragStart &e) {
 
 	oldPos = box.pos;
 	dragPos = APP->scene->rack->mousePos.minus(box.pos);
+	APP->scene->rack->updateModuleDragPositions();
 }
 
 void ModuleWidget::onDragEnd(const event::DragEnd &e) {
-	if (!box.pos.isEqual(oldPos)) {
-		// history::ModuleMove
-		history::ModuleMove *h = new history::ModuleMove;
-		h->moduleId = module->id;
-		h->oldPos = oldPos;
-		h->newPos = box.pos;
-		APP->history->push(h);
+	history::ComplexAction *h = APP->scene->rack->getModuleDragAction();
+	if (!h) {
+		delete h;
+		return;
 	}
+	APP->history->push(h);
 }
 
 void ModuleWidget::onDragMove(const event::DragMove &e) {

src/app/RackWidget.cpp

@@ -521,10 +521,10 @@ void RackWidget::setModulePosForce(ModuleWidget *mw, math::Vec pos) {
 
 ModuleWidget *RackWidget::getModule(int moduleId) {
 	for (widget::Widget *w : moduleContainer->children) {
-		ModuleWidget *moduleWidget = dynamic_cast<ModuleWidget*>(w);
-		assert(moduleWidget);
-		if (moduleWidget->module->id == moduleId)
-			return moduleWidget;
+		ModuleWidget *mw = dynamic_cast<ModuleWidget*>(w);
+		assert(mw);
+		if (mw->module->id == moduleId)
+			return mw;
 	}
 	return NULL;
 }
@@ -533,6 +533,34 @@ bool RackWidget::isEmpty() {
 	return moduleContainer->children.empty();
 }
 
+void RackWidget::updateModuleDragPositions() {
+	moduleDragPositions.clear();
+	for (widget::Widget *w : moduleContainer->children) {
+		ModuleWidget *mw = dynamic_cast<ModuleWidget*>(w);
+		assert(mw);
+		moduleDragPositions[mw->module->id] = mw->box.pos;
+	}
+}
+
+history::ComplexAction *RackWidget::getModuleDragAction() {
+	history::ComplexAction *h = new history::ComplexAction;
+
+	for (widget::Widget *w : moduleContainer->children) {
+		ModuleWidget *mw = dynamic_cast<ModuleWidget*>(w);
+		assert(mw);
+		math::Vec pos = moduleDragPositions.at(mw->module->id);
+		if (!pos.isEqual(mw->box.pos)) {
+			history::ModuleMove *mmh = new history::ModuleMove;
+			mmh->moduleId = mw->module->id;
+			mmh->oldPos = pos;
+			mmh->newPos = mw->box.pos;
+			h->push(mmh);
+		}
+	}
+	return h;
+}
+
+
 void RackWidget::clearCables() {
 	for (widget::Widget *w : cableContainer->children) {
 		CableWidget *cw = dynamic_cast<CableWidget*>(w);

src/engine/Engine.cpp

@@ -294,21 +294,16 @@ static void Engine_relaunchWorkers(Engine *that) {
 	assert(1 <= internal->threadCount);
 
 	// Stop all workers
-	DEBUG("1");
 	for (EngineWorker &worker : internal->workers) {
 		worker.stop();
 	}
-	DEBUG("2");
 	internal->engineBarrier.wait();
 
 	// Destroy all workers
-	DEBUG("3");
 	for (EngineWorker &worker : internal->workers) {
 		worker.join();
 	}
-	DEBUG("4");
 	internal->workers.resize(0);
-	DEBUG("5");
 
 	// Configure main thread
 	system::setThreadRealTime(internal->realTime);
@@ -318,7 +313,6 @@ static void Engine_relaunchWorkers(Engine *that) {
 	internal->workerBarrier.total = internal->threadCount;
 
 	// Create workers
-	DEBUG("6");
 	internal->workers.resize(internal->threadCount - 1);
 	for (int id = 1; id < internal->threadCount; id++) {
 		EngineWorker &worker = internal->workers[id - 1];
@@ -326,7 +320,6 @@ static void Engine_relaunchWorkers(Engine *that) {
 		worker.engine = that;
 		worker.start();
 	}
-	DEBUG("7");
 }
 
 static void Engine_run(Engine *that) {

src/history.cpp

@@ -32,6 +32,10 @@ void ComplexAction::push(Action *action) {
 	actions.push_back(action);
 }
 
+bool ComplexAction::isEmpty() {
+	return actions.empty();
+}
+
 
 ModuleAdd::~ModuleAdd() {
 	json_decref(moduleJ);