Fixed potential deadlocks during WM_ACTIVATEAPP

DDrawCompat/DDraw/ActivateAppHandler.cpp

@@ -1,3 +1,5 @@
+#include <atomic>
+
 #include <ddraw.h>
 
 #include "Common/Hook.h"
@@ -12,6 +14,8 @@ namespace
 {
 	Win32::FontSmoothing::SystemSettings g_fontSmoothingSettings = {};
 	WNDPROC g_origDdWndProc = nullptr;
+	std::atomic<DWORD> g_activateAppThreadId = 0;
+	HWND g_delayedFocusWnd = nullptr;
 
 	void activateApp()
 	{
@@ -43,7 +47,16 @@ namespace
 			{
 				deactivateApp();
 			}
+
+			g_activateAppThreadId = GetCurrentThreadId();
+			g_delayedFocusWnd = nullptr;
 			LRESULT result = g_origDdWndProc(hwnd, uMsg, wParam, lParam);
+			g_activateAppThreadId = 0;
+			if (g_delayedFocusWnd)
+			{
+				CALL_ORIG_FUNC(SetFocus)(g_delayedFocusWnd);
+			}
+
 			isDisplayChangeNotificationEnabled = true;
 			DDraw::RealPrimarySurface::enableUpdates();
 			return LOG_RESULT(result);
@@ -62,12 +75,39 @@ namespace
 
 		return LOG_RESULT(g_origDdWndProc(hwnd, uMsg, wParam, lParam));
 	}
+
+	HWND WINAPI setFocus(HWND hWnd)
+	{
+		if (GetCurrentThreadId() == g_activateAppThreadId && IsWindow(hWnd))
+		{
+			g_delayedFocusWnd = hWnd;
+			return GetFocus();
+		}
+		return CALL_ORIG_FUNC(SetFocus)(hWnd);
+	}
+
+	BOOL WINAPI showWindow(HWND hWnd, int  nCmdShow)
+	{
+		if (GetCurrentThreadId() == g_activateAppThreadId && IsWindow(hWnd))
+		{
+			BOOL result = IsWindowVisible(hWnd);
+			ShowWindowAsync(hWnd, nCmdShow);
+			return result;
+		}
+		return CALL_ORIG_FUNC(ShowWindow)(hWnd, nCmdShow);
+	}
 }
 
 namespace DDraw
 {
 	namespace ActivateAppHandler
 	{
+		void installHooks()
+		{
+			HOOK_FUNCTION(user32, SetFocus, setFocus);
+			HOOK_FUNCTION(user32, ShowWindow, showWindow);
+		}
+
 		void setCooperativeLevel(HWND hwnd, DWORD flags)
 		{
 			static bool isDdWndProcHooked = false;

DDrawCompat/DDraw/ActivateAppHandler.h

@@ -8,6 +8,7 @@ namespace DDraw
 {
 	namespace ActivateAppHandler
 	{
+		void installHooks();
 		void setCooperativeLevel(HWND hwnd, DWORD flags);
 	}
 }

DDrawCompat/DDraw/Hooks.cpp

@@ -103,6 +103,7 @@ namespace DDraw
 	void installHooks()
 	{
 		RealPrimarySurface::init();
+		ActivateAppHandler::installHooks();
 
 		Win32::Registry::unsetValue(
 			HKEY_LOCAL_MACHINE, "SOFTWARE\\Microsoft\\DirectDraw", "EmulationOnly");