Terminate the application when the UI thread is dead. Close #343

lib/init.dart

@@ -1,4 +1,7 @@
+import 'dart:async';
+
 import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_saf/flutter_saf.dart';
 import 'package:rhttp/rhttp.dart';
 import 'package:venera/foundation/app.dart';
@@ -51,6 +54,14 @@ Future<void> init() async {
   FlutterError.onError = (details) {
     Log.error("Unhandled Exception", "${details.exception}\n${details.stack}");
   };
+  if (App.isWindows) {
+    // Report to the monitor thread that the app is running
+    // https://github.com/venera-app/venera/issues/343
+    Timer.periodic(const Duration(seconds: 1), (_) {
+      const methodChannel = MethodChannel('venera/method_channel');
+      methodChannel.invokeMethod("heartBeat");
+    });
+  }
 }
 
 void _checkOldConfigs() {

windows/runner/flutter_window.cpp

@@ -10,11 +10,16 @@
 #include <flutter/event_stream_handler_functions.h>
 #include <flutter/standard_method_codec.h>
 #include "flutter/generated_plugin_registrant.h"
+#include <thread>
 
 #define _CRT_SECURE_NO_WARNINGS
 
 std::unique_ptr<flutter::EventSink<flutter::EncodableValue>>&& mouseEvents = nullptr;
 
+std::atomic<bool> mainThreadAlive(true);
+std::atomic<std::chrono::steady_clock::time_point> lastHeartbeat(std::chrono::steady_clock::now());
+std::thread* monitorThread = nullptr;
+
 char* wideCharToMultiByte(wchar_t* pWCStrKey)
 {
     size_t pSize = WideCharToMultiByte(CP_OEMCP, 0, pWCStrKey, wcslen(pWCStrKey), NULL, 0, NULL, NULL);
@@ -45,6 +50,22 @@ FlutterWindow::FlutterWindow(const flutter::DartProject& project)
 
 FlutterWindow::~FlutterWindow() {}
 
+void monitorUIThread() {
+    const auto timeout = std::chrono::seconds(5);
+
+    while (mainThreadAlive.load()) {
+        auto now = std::chrono::steady_clock::now();
+        auto duration = now - lastHeartbeat.load();
+
+        if (duration > timeout) {
+            std::cerr << "The UI thread is dead. Terminate the application.";
+            std::exit(0);
+        }
+
+        std::this_thread::sleep_for(std::chrono::seconds(1));
+    }
+}
+
 bool FlutterWindow::OnCreate() {
   if (!Win32Window::OnCreate()) {
     return false;
@@ -78,6 +99,13 @@ bool FlutterWindow::OnCreate() {
           result->Success(flutter::EncodableValue("No Proxy"));
         delete(res);
       }
+      else if (call.method_name() == "heartBeat") {
+          if (monitorThread == nullptr) {
+              monitorThread = new std::thread{ monitorUIThread };
+          }
+          lastHeartbeat = std::chrono::steady_clock::now();
+          result->Success();
+      }
   });
 
   flutter::EventChannel<> channel2(
@@ -163,6 +191,10 @@ void FlutterWindow::OnDestroy() {
   }
 
   Win32Window::OnDestroy();
+  if (monitorThread != nullptr) {
+      mainThreadAlive = false;
+      monitorThread->join();
+  }
 }
 
 void mouse_side_button_listener(unsigned int input)