From 900921736675047806c92e5b0e276e7a74cfef9c Mon Sep 17 00:00:00 2001
From: Quantum <quantum2048@gmail.com>
Date: Sun, 14 Sep 2025 16:26:05 -0400
Subject: [PATCH] [idd] helper: stop using MsgWaitForMultipleObjects

`MsgWaitForMultipleObjects` doesn't handle inner message loops,
which may happen during `TrackPopupMenu`, causing exits to fail.
---
 idd/LGIddHelper/CNotifyWindow.cpp | 16 +++++++++-
 idd/LGIddHelper/CNotifyWindow.h   |  4 +++
 idd/LGIddHelper/main.cpp          | 53 +++++++++++--------------------
 3 files changed, 38 insertions(+), 35 deletions(-)

diff --git a/idd/LGIddHelper/CNotifyWindow.cpp b/idd/LGIddHelper/CNotifyWindow.cpp
index a03a4989..77373df6 100644
--- a/idd/LGIddHelper/CNotifyWindow.cpp
+++ b/idd/LGIddHelper/CNotifyWindow.cpp
@@ -22,7 +22,8 @@ bool CNotifyWindow::registerClass()
   return s_atom;
 }
 
-CNotifyWindow::CNotifyWindow() : m_iconData({ 0 }), m_menu(CreatePopupMenu())
+CNotifyWindow::CNotifyWindow() : m_iconData({ 0 }), m_menu(CreatePopupMenu()),
+  closeRequested(false)
 {
   CreateWindowEx(0, MAKEINTATOM(s_atom), NULL,
     0, 0, 0, 0, 0, NULL, NULL, hInstance, this);
@@ -63,6 +64,13 @@ LRESULT CNotifyWindow::onCreate()
   return 0;
 }
 
+LRESULT CNotifyWindow::onClose()
+{
+  if (closeRequested)
+    destroy();
+  return 0;
+}
+
 LRESULT CNotifyWindow::onNotifyIcon(UINT uEvent, WORD wIconId, int x, int y)
 {
   switch (uEvent)
@@ -95,3 +103,9 @@ void CNotifyWindow::registerIcon()
   if (!Shell_NotifyIcon(NIM_SETVERSION, &m_iconData))
     DEBUG_ERROR_HR(GetLastError(), "Shell_NotifyIcon(NIM_SETVERSION)");
 }
+
+void CNotifyWindow::close()
+{
+  closeRequested = true;
+  PostMessage(m_hwnd, WM_CLOSE, 0, 0);
+}
diff --git a/idd/LGIddHelper/CNotifyWindow.h b/idd/LGIddHelper/CNotifyWindow.h
index e7186c80..690cb93a 100644
--- a/idd/LGIddHelper/CNotifyWindow.h
+++ b/idd/LGIddHelper/CNotifyWindow.h
@@ -10,15 +10,19 @@ class CNotifyWindow : public CWindow
 
   NOTIFYICONDATA m_iconData;
   HMENU m_menu;
+  bool closeRequested;
 
   LRESULT onNotifyIcon(UINT uEvent, WORD wIconId, int x, int y);
   void registerIcon();
 
   virtual LRESULT handleMessage(UINT uMsg, WPARAM wParam, LPARAM lParam) override;
   virtual LRESULT onCreate() override;
+  virtual LRESULT onClose() override;
 
 public:
   CNotifyWindow();
   ~CNotifyWindow() override;
   static bool registerClass();
+
+  void close();
 };
diff --git a/idd/LGIddHelper/main.cpp b/idd/LGIddHelper/main.cpp
index a1fa63f8..c772c67c 100644
--- a/idd/LGIddHelper/main.cpp
+++ b/idd/LGIddHelper/main.cpp
@@ -31,6 +31,13 @@ static HandleT<HANDLENullTraits> l_process;
 
 static void Launch();
 
+void CALLBACK DestroyNotifyWindow(PVOID lpParam, BOOLEAN bTimedOut)
+{
+  DEBUG_INFO("Parent process exited, exiting...");
+  CNotifyWindow *window = (CNotifyWindow *)lpParam;
+  window->close();
+}
+
 int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nShowCmd)
 {
   wchar_t buffer[MAX_PATH];
@@ -79,46 +86,24 @@ int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
     return EXIT_FAILURE;
   }
 
+  if (!g_pipe.Init())
+    return EXIT_FAILURE;
+
   CNotifyWindow window;
 
-  if (!g_pipe.Init())
+  HANDLE hWait;
+  if (!RegisterWaitForSingleObject(&hWait, hParent.Get(), DestroyNotifyWindow, &window, INFINITE, WT_EXECUTEONLYONCE))
+    DEBUG_ERROR_HR(GetLastError(), "Failed to RegisterWaitForSingleObject");
+
+  MSG msg;
+  while (GetMessage(&msg, NULL, 0, 0) > 0)
   {
-    window.destroy();
-    hParent.Close();
+    TranslateMessage(&msg);
+    DispatchMessage(&msg);
   }
 
-  while (true)
-  {
-    DWORD dwHandles = hParent.IsValid() ? 1 : 0;
-    LPHANDLE lpHandles = hParent.GetAddressOf();
+  (void) UnregisterWait(hWait);
 
-    DWORD dwResult = MsgWaitForMultipleObjects(dwHandles, lpHandles, FALSE, INFINITE, QS_ALLINPUT);
-    if (dwResult == WAIT_FAILED)
-    {
-      DEBUG_ERROR_HR(GetLastError(), "MsgWaitForMultipleObjects Failed");
-      g_pipe.DeInit();
-      return EXIT_FAILURE;
-    }
-    else if (dwResult == WAIT_OBJECT_0 + dwHandles)
-    {
-      MSG msg;
-      while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
-      {
-        if (msg.message == WM_QUIT)
-          goto exit;
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-      }
-    }
-    else
-    {
-      DEBUG_INFO("Parent process exited, exiting...");
-      hParent.Close();
-      window.destroy();
-    }
-  }
-
-exit:
   DEBUG_INFO("Helper window destroyed.");
   g_pipe.DeInit();
   return EXIT_SUCCESS;