Add option to stop plugin in case unclean shutdown is detected

CMakeLists.txt

@@ -184,6 +184,8 @@ target_sources(
           lib/utils/canvas-helpers.hpp
           lib/utils/condition-logic.cpp
           lib/utils/condition-logic.hpp
+          lib/utils/crash-handler.cpp
+          lib/utils/crash-handler.hpp
           lib/utils/curl-helper.cpp
           lib/utils/curl-helper.hpp
           lib/utils/cursor-shape-changer.cpp

data/locale/en-US.ini

@@ -1390,6 +1390,8 @@ AdvSceneSwitcher.hotkey.macro.segment.remove="Remove selected macro segment"
 AdvSceneSwitcher.askBackup="Detected a new version of the Advanced Scene Switcher.\nShould a backup of the old settings be created?"
 AdvSceneSwitcher.askForMacro="Select macro{{macroSelection}}"
 
+AdvSceneSwitcher.crashDetected="OBS did not shut down cleanly (for example, due to a crash or freeze).\n\nThe Advanced Scene Switcher plugin would normally start automatically.\nWould you like to keep it stopped for now?"
+
 AdvSceneSwitcher.close="Close"
 AdvSceneSwitcher.browse="Browse"
 

lib/advanced-scene-switcher.cpp

@@ -1,5 +1,6 @@
 #include "advanced-scene-switcher.hpp"
 #include "backup.hpp"
+#include "crash-handler.hpp"
 #include "log-helper.hpp"
 #include "macro-helpers.hpp"
 #include "obs-module-helper.hpp"
@@ -207,9 +208,15 @@ static void SaveSceneSwitcher(obs_data_t *save_data, bool saving, void *)
 		switcher->LoadSettings(data);
 		switcher->m.unlock();
 
-		if (!switcher->stop) {
-			switcher->Start();
+		if (switcher->stop) {
+			return;
 		}
+
+		if (ShouldSkipPluginStartOnUncleanShutdown()) {
+			return;
+		}
+
+		switcher->Start();
 	}
 }
 

lib/utils/crash-handler.cpp

@@ -0,0 +1,135 @@
+#include "crash-handler.hpp"
+#include "log-helper.hpp"
+#include "obs-module-helper.hpp"
+#include "plugin-state-helpers.hpp"
+#include "ui-helpers.hpp"
+
+#include <obs-frontend-api.h>
+#include <obs-module.h>
+
+#include <QDir>
+#include <QFile>
+
+#include <thread>
+
+namespace advss {
+
+static constexpr std::string_view sentinel = ".running";
+
+#ifndef NDEBUG
+static constexpr bool handleUncleanShutdown = false;
+#else
+static constexpr bool handleUncleanShutdown = true;
+#endif
+
+static bool wasCleanShutdown = false;
+
+static void setup();
+static bool setupDone = []() {
+	AddPluginInitStep(setup);
+	return true;
+}();
+
+static void handleShutdown(enum obs_frontend_event event, void *)
+{
+	if (event != OBS_FRONTEND_EVENT_EXIT) {
+		return;
+	}
+
+	char *sentinelFile = obs_module_config_path(sentinel.data());
+	if (!sentinelFile) {
+		return;
+	}
+
+	QFile file(sentinelFile);
+	if (!file.exists()) {
+		bfree(sentinelFile);
+		return;
+	}
+
+	if (!file.remove()) {
+		blog(LOG_WARNING, "failed to remove sentinel file");
+	}
+
+	bfree(sentinelFile);
+}
+
+static void setup()
+{
+	char *sentinelFile = obs_module_config_path(sentinel.data());
+	if (!sentinelFile) {
+		return;
+	}
+
+	QString dirPath = QFileInfo(sentinelFile).absolutePath();
+	QDir dir(dirPath);
+	if (!dir.exists()) {
+		if (!dir.mkpath(dirPath)) {
+			blog(LOG_WARNING,
+			     "failed to create directory for sentinel file");
+			bfree(sentinelFile);
+			return;
+		}
+	}
+
+	QFile file(sentinelFile);
+
+	wasCleanShutdown = file.exists();
+
+	if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
+		blog(LOG_WARNING, "failed to create sentinel file");
+		bfree(sentinelFile);
+		return;
+	}
+
+	file.write("running");
+	file.close();
+	bfree(sentinelFile);
+
+	obs_frontend_add_event_callback(handleShutdown, nullptr);
+	return;
+}
+
+static bool wasUncleanShutdown()
+{
+	static bool alreadyHandled = false;
+
+	if (!handleUncleanShutdown || !wasCleanShutdown || alreadyHandled) {
+		alreadyHandled = true;
+		return false;
+	}
+
+	alreadyHandled = true;
+	blog(LOG_WARNING, "unclean shutdown detected");
+	return true;
+}
+
+static bool askForStartupSkip()
+{
+	return DisplayMessage(obs_module_text("AdvSceneSwitcher.crashDetected"),
+			      true, false);
+}
+
+bool ShouldSkipPluginStartOnUncleanShutdown()
+{
+	if (!wasUncleanShutdown()) {
+		return false;
+	}
+
+	std::thread t([]() {
+		obs_queue_task(
+			OBS_TASK_UI,
+			[](void *) {
+				const bool skipStart = askForStartupSkip();
+				if (!skipStart) {
+					StartPlugin();
+				}
+			},
+			nullptr, false);
+	});
+	t.detach();
+
+	return true;
+}
+
+} // namespace advss

lib/utils/crash-handler.hpp

@@ -0,0 +1,7 @@
+#pragma once
+
+namespace advss {
+
+bool ShouldSkipPluginStartOnUncleanShutdown();
+
+} // namespace advss