Fixed sporadic deadlock caused by presentation window title update

Fixes occasional deadlock when alt-tabbing in Age of Wonders: Shadow Magic.

DDrawCompat/Gdi/PresentationWindow.cpp

@@ -9,9 +9,23 @@ namespace
 {
 	ATOM g_classAtom = 0;
 
+	std::wstring getWindowText(HWND hwnd)
+	{
+		const UINT MAX_LEN = 256;
+		wchar_t windowText[MAX_LEN] = {};
+		InternalGetWindowText(hwnd, windowText, MAX_LEN);
+		return windowText;
+	}
+
 	LRESULT CALLBACK presentationWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 	{
 		LOG_FUNC("presentationWindowProc", Compat::WindowMessageStruct(hwnd, uMsg, wParam, lParam));
+		if (WM_NULL == uMsg && WM_GETTEXT == wParam && WM_SETTEXT == lParam)
+		{
+			std::wstring windowText(L"[DDrawCompat] " + getWindowText(GetParent(hwnd)));
+			SetWindowTextW(hwnd, windowText.c_str());
+			return LOG_RESULT(0);
+		}
 		return LOG_RESULT(CALL_ORIG_FUNC(DefWindowProcA)(hwnd, uMsg, wParam, lParam));
 	}
 }

DDrawCompat/Gdi/WinProc.cpp

@@ -54,7 +54,6 @@ namespace
 
 	decltype(&DwmSetIconicThumbnail) g_dwmSetIconicThumbnail = nullptr;
 
-	wchar_t g_dummyWindowText;
 	std::map<HMENU, UINT> g_menuMaxHeight;
 	std::set<Gdi::WindowPosChangeNotifyFunc> g_windowPosChangeNotifyFuncs;
 
@@ -71,7 +70,6 @@ namespace
 
 	void dwmSendIconicThumbnail(HWND hwnd, LONG width, LONG height);
 	WindowProc getWindowProc(HWND hwnd);
-	std::wstring getWindowText(HWND hwnd, WNDPROC wndProc);
 	bool isUser32ScrollBar(HWND hwnd);
 	void onDestroyWindow(HWND hwnd);
 	void onGetMinMaxInfo(MINMAXINFO& mmi);
@@ -146,19 +144,6 @@ namespace
 			}
 			break;
 
-		case WM_NULL:
-			if (WM_GETTEXT == wParam && reinterpret_cast<LPARAM>(&g_dummyWindowText) == lParam)
-			{
-				auto presentationWindow = Gdi::Window::getPresentationWindow(hwnd);
-				if (presentationWindow)
-				{
-					std::wstring windowText(L"[DDrawCompat] " + getWindowText(hwnd, wndProc));
-					SendMessageW(presentationWindow, WM_SETTEXT, 0, reinterpret_cast<LPARAM>(windowText.c_str()));
-				}
-				return 0;
-			}
-			break;
-
 		case WM_SYNCPAINT:
 			if (Gdi::Window::isTopLevelWindow(hwnd))
 			{
@@ -412,25 +397,6 @@ namespace
 		return it != g_windowProc.end() ? it->second : WindowProc{};
 	}
 
-	std::wstring getWindowText(HWND hwnd, WNDPROC wndProc)
-	{
-		const UINT MAX_LEN = 256;
-		if (IsWindowUnicode(hwnd))
-		{
-			wchar_t windowText[MAX_LEN] = {};
-			CallWindowProcW(wndProc, hwnd, WM_GETTEXT, MAX_LEN, reinterpret_cast<LPARAM>(windowText));
-			windowText[MAX_LEN - 1] = 0;
-			return windowText;
-		}
-		else
-		{
-			char windowText[MAX_LEN] = {};
-			CallWindowProcA(wndProc, hwnd, WM_GETTEXT, MAX_LEN, reinterpret_cast<LPARAM>(windowText));
-			windowText[MAX_LEN - 1] = 0;
-			return std::wstring(windowText, windowText + strlen(windowText));
-		}
-	}
-
 	template <auto func, typename... Params>
 	int WINAPI messageBox(Params... params)
 	{
@@ -813,7 +779,11 @@ namespace
 		case EVENT_OBJECT_NAMECHANGE:
 			if (OBJID_WINDOW == idObject && Gdi::Window::isTopLevelWindow(hwnd) && !Gdi::GuiThread::isGuiThreadWindow(hwnd))
 			{
-				Gdi::WinProc::updatePresentationWindowText(hwnd);
+				auto presentationWindow = Gdi::Window::getPresentationWindow(hwnd);
+				if (presentationWindow)
+				{
+					Gdi::Window::updatePresentationWindowText(presentationWindow);
+				}
 				break;
 			}
 
@@ -1038,11 +1008,6 @@ namespace Gdi
 			}
 		}
 
-		void updatePresentationWindowText(HWND owner)
-		{
-			SendNotifyMessageW(owner, WM_NULL, WM_GETTEXT, reinterpret_cast<LPARAM>(&g_dummyWindowText));
-		}
-
 		void watchWindowPosChanges(WindowPosChangeNotifyFunc notifyFunc)
 		{
 			g_windowPosChangeNotifyFuncs.insert(notifyFunc);

DDrawCompat/Gdi/Window.cpp

@@ -290,7 +290,7 @@ namespace
 			if (!isLayered)
 			{
 				it->second.presentationWindow = Gdi::PresentationWindow::create(hwnd);
-				Gdi::WinProc::updatePresentationWindowText(hwnd);
+				Gdi::Window::updatePresentationWindowText(it->second.presentationWindow);
 			}
 			else if (it->second.presentationWindow)
 			{
@@ -662,7 +662,7 @@ namespace Gdi
 
 				if (it->second.presentationWindow)
 				{
-					Gdi::WinProc::updatePresentationWindowText(hwnd);
+					updatePresentationWindowText(it->second.presentationWindow);
 					Gdi::GuiThread::setWindowRgn(it->second.presentationWindow, getWindowRgn(hwnd));
 				}
 
@@ -729,6 +729,11 @@ namespace Gdi
 				});
 		}
 
+		void updatePresentationWindowText(HWND presentationWindow)
+		{
+			PostMessageW(presentationWindow, WM_NULL, WM_GETTEXT, WM_SETTEXT);
+		}
+
 		void updateWindowPos(HWND hwnd)
 		{
 			if (IsWindowVisible(hwnd) && !IsIconic(hwnd))

DDrawCompat/Gdi/Window.h

@@ -33,6 +33,7 @@ namespace Gdi
 		void updateLayeredWindowInfo(HWND hwnd, HDC hdcSrc, const POINT* pptSrc,
 			COLORREF colorKey, BYTE alpha, BYTE alphaFormat);
 		void updatePresentationWindowPos(HWND presentationWindow, HWND owner);
+		void updatePresentationWindowText(HWND presentationWindow);
 		void updateWindowPos(HWND hwnd);
 	}
 }