Fix potential freeze or crash with "Show match" dialog

This is a workaround to handle random segfaults triggered when using ...
QMetaObject::invokeMethod(this, "RedrawImage", -Qt::QueuedConnection,
		   Q_ARG(QImage, image));
... from within CheckForMatchLoop().
Even using BlockingQueuedConnection causes deadlocks.

src/external-macro-modules/opencv/macro-condition-video.cpp

@@ -268,7 +268,8 @@ static inline void populateConditionSelection(QComboBox *list)
 
 MacroConditionVideoEdit::MacroConditionVideoEdit(
 	QWidget *parent, std::shared_ptr<MacroConditionVideo> entryData)
-	: QWidget(parent), _matchDialog(this, entryData.get())
+	: QWidget(parent),
+	  _matchDialog(this, entryData.get(), &GetSwitcher()->m)
 {
 	_videoSelection = new QComboBox();
 	_condition = new QComboBox();

src/external-macro-modules/opencv/video-match-dialog.cpp

@@ -3,12 +3,16 @@
 #include "opencv-helpers.hpp"
 #include "utility.hpp"
 
+#include <condition_variable>
+
 ShowMatchDialog::ShowMatchDialog(QWidget *parent,
-				 MacroConditionVideo *conditionData)
+				 MacroConditionVideo *conditionData,
+				 std::mutex *mutex)
 	: QDialog(parent),
 	  _conditionData(conditionData),
 	  _imageLabel(new QLabel),
-	  _scrollArea(new QScrollArea)
+	  _scrollArea(new QScrollArea),
+	  _mtx(mutex)
 {
 	setWindowTitle("Advanced Scene Switcher");
 	_statusLabel = new QLabel(obs_module_text(
@@ -20,6 +24,16 @@ ShowMatchDialog::ShowMatchDialog(QWidget *parent,
 	layout->addWidget(_statusLabel);
 	layout->addWidget(_scrollArea);
 	setLayout(layout);
+
+	// This is a workaround to handle random segfaults triggered when using:
+	// QMetaObject::invokeMethod(this, "RedrawImage", -Qt::QueuedConnection,
+	//			   Q_ARG(QImage, image));
+	// from within CheckForMatchLoop().
+	// Even using BlockingQueuedConnection causes deadlocks
+	_timer.setInterval(500);
+	QWidget::connect(&_timer, &QTimer::timeout, this,
+			 &ShowMatchDialog::Resize);
+	_timer.start();
 }
 
 ShowMatchDialog::~ShowMatchDialog()
@@ -43,20 +57,24 @@ void ShowMatchDialog::ShowMatch()
 	_thread = std::thread(&ShowMatchDialog::CheckForMatchLoop, this);
 }
 
-void ShowMatchDialog::RedrawImage(QImage img)
+void ShowMatchDialog::Resize()
 {
-	_imageLabel->setPixmap(QPixmap::fromImage(img));
 	_imageLabel->adjustSize();
 }
 
 void ShowMatchDialog::CheckForMatchLoop()
 {
+	std::condition_variable cv;
 	while (!_stop) {
+		std::unique_lock<std::mutex> lock(*_mtx);
 		auto source = obs_weak_source_get_source(
 			_conditionData->_videoSource);
 		ScreenshotHelper screenshot(source);
 		obs_source_release(source);
-		std::this_thread::sleep_for(std::chrono::seconds(1));
+		cv.wait_for(lock, std::chrono::seconds(1));
+		if (_stop) {
+			return;
+		}
 		if (!screenshot.done) {
 			_statusLabel->setText(obs_module_text(
 				"AdvSceneSwitcher.condition.video.screenshotFail"));
@@ -71,9 +89,7 @@ void ShowMatchDialog::CheckForMatchLoop()
 			continue;
 		}
 		auto image = MarkMatch(screenshot.image);
-		QMetaObject::invokeMethod(this, "RedrawImage",
-					  Qt::QueuedConnection,
-					  Q_ARG(QImage, image));
+		_imageLabel->setPixmap(QPixmap::fromImage(screenshot.image));
 	}
 }
 

src/external-macro-modules/opencv/video-match-dialog.hpp

@@ -3,7 +3,9 @@
 #include <QDialog>
 #include <QLabel>
 #include <QScrollArea>
+#include <QTimer>
 #include <thread>
+#include <mutex>
 
 class MacroConditionVideo;
 
@@ -11,12 +13,13 @@ class ShowMatchDialog : public QDialog {
 	Q_OBJECT
 
 public:
-	ShowMatchDialog(QWidget *parent, MacroConditionVideo *_conditionData);
+	ShowMatchDialog(QWidget *parent, MacroConditionVideo *_conditionData,
+			std::mutex *mutex);
 	virtual ~ShowMatchDialog();
 	void ShowMatch();
 
 private slots:
-	void RedrawImage(QImage img);
+	void Resize();
 
 private:
 	void CheckForMatchLoop();
@@ -26,6 +29,8 @@ private:
 	QScrollArea *_scrollArea;
 	QLabel *_statusLabel;
 	QLabel *_imageLabel;
+	QTimer _timer;
+	std::mutex *_mtx;
 	std::thread _thread;
 	std::atomic_bool _stop = {false};
 };

src/macro-action-edit.cpp

@@ -156,16 +156,18 @@ void AdvSceneSwitcher::AddMacroAction(int idx)
 		MacroActionSwitchScene temp(nullptr);
 		id = temp.GetId();
 	}
-	std::lock_guard<std::mutex> lock(switcher->m);
-	macro->Actions().emplace(macro->Actions().begin() + idx,
-				 MacroActionFactory::Create(id, macro));
-	if (idx - 1 >= 0) {
-		auto data = obs_data_create();
-		macro->Actions().at(idx - 1)->Save(data);
-		macro->Actions().at(idx)->Load(data);
-		obs_data_release(data);
+	{
+		std::lock_guard<std::mutex> lock(switcher->m);
+		macro->Actions().emplace(macro->Actions().begin() + idx,
+					 MacroActionFactory::Create(id, macro));
+		if (idx - 1 >= 0) {
+			auto data = obs_data_create();
+			macro->Actions().at(idx - 1)->Save(data);
+			macro->Actions().at(idx)->Load(data);
+			obs_data_release(data);
+		}
+		macro->UpdateActionIndices();
 	}
-	macro->UpdateActionIndices();
 
 	clearLayout(actionsList->ContentLayout(), idx);
 	PopulateMacroActions(*macro, idx);
@@ -206,11 +208,13 @@ void AdvSceneSwitcher::RemoveMacroAction(int idx)
 		return;
 	}
 
-	std::lock_guard<std::mutex> lock(switcher->m);
-	macro->Actions().erase(macro->Actions().begin() + idx);
-	switcher->abortMacroWait = true;
-	switcher->macroWaitCv.notify_all();
-	macro->UpdateActionIndices();
+	{
+		std::lock_guard<std::mutex> lock(switcher->m);
+		macro->Actions().erase(macro->Actions().begin() + idx);
+		switcher->abortMacroWait = true;
+		switcher->macroWaitCv.notify_all();
+		macro->UpdateActionIndices();
+	}
 
 	clearLayout(actionsList->ContentLayout(), idx);
 	PopulateMacroActions(*macro, idx);

src/macro-condition-edit.cpp

@@ -282,18 +282,20 @@ void AdvSceneSwitcher::AddMacroCondition(int idx)
 		id = temp.GetId();
 		logic = LogicType::ROOT_NONE;
 	}
-	std::lock_guard<std::mutex> lock(switcher->m);
-	auto cond = macro->Conditions().emplace(
-		macro->Conditions().begin() + idx,
-		MacroConditionFactory::Create(id, macro));
-	if (idx - 1 >= 0) {
-		auto data = obs_data_create();
-		macro->Conditions().at(idx - 1)->Save(data);
-		macro->Conditions().at(idx)->Load(data);
-		obs_data_release(data);
+	{
+		std::lock_guard<std::mutex> lock(switcher->m);
+		auto cond = macro->Conditions().emplace(
+			macro->Conditions().begin() + idx,
+			MacroConditionFactory::Create(id, macro));
+		if (idx - 1 >= 0) {
+			auto data = obs_data_create();
+			macro->Conditions().at(idx - 1)->Save(data);
+			macro->Conditions().at(idx)->Load(data);
+			obs_data_release(data);
+		}
+		(*cond)->SetLogicType(logic);
+		macro->UpdateConditionIndices();
 	}
-	(*cond)->SetLogicType(logic);
-	macro->UpdateConditionIndices();
 
 	clearLayout(conditionsList->ContentLayout(), idx);
 	PopulateMacroConditions(*macro, idx);
@@ -334,13 +336,15 @@ void AdvSceneSwitcher::RemoveMacroCondition(int idx)
 		return;
 	}
 
-	std::lock_guard<std::mutex> lock(switcher->m);
-	macro->Conditions().erase(macro->Conditions().begin() + idx);
-	macro->UpdateConditionIndices();
+	{
+		std::lock_guard<std::mutex> lock(switcher->m);
+		macro->Conditions().erase(macro->Conditions().begin() + idx);
+		macro->UpdateConditionIndices();
 
-	if (idx == 0 && macro->Conditions().size() > 0) {
-		auto newRoot = macro->Conditions().at(0);
-		newRoot->SetLogicType(LogicType::ROOT_NONE);
+		if (idx == 0 && macro->Conditions().size() > 0) {
+			auto newRoot = macro->Conditions().at(0);
+			newRoot->SetLogicType(LogicType::ROOT_NONE);
+		}
 	}
 
 	clearLayout(conditionsList->ContentLayout(), idx);