From 100e400fed27d568d3cd98ccc9b6ac7b74fc678d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=CE=B6eh=20Matt?= <5415177+ZehMatt@users.noreply.github.com>
Date: Thu, 14 Jul 2022 16:46:31 +0300
Subject: [PATCH] Dynamically obtain the function pointer to IsHungAppWindow

---
 .../crashcatcher/windows_crashmonitor.cpp     | 26 +++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/components/crashcatcher/windows_crashmonitor.cpp b/components/crashcatcher/windows_crashmonitor.cpp
index e76e8897e1..214557e3a7 100644
--- a/components/crashcatcher/windows_crashmonitor.cpp
+++ b/components/crashcatcher/windows_crashmonitor.cpp
@@ -17,7 +17,29 @@
 namespace Crash
 {
     std::unordered_map<HWINEVENTHOOK, CrashMonitor*> CrashMonitor::smEventHookOwners{};
+    
+    using IsHungAppWindowFn = BOOL(WINAPI*)(HWND hwnd);
+
+    // Obtains the pointer to user32.IsHungAppWindow, this function may be removed in the future.
+    // See: https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-ishungappwindow
+    static IsHungAppWindowFn getIsHungAppWindow() noexcept
+    {
+        static IsHungAppWindowFn isHungAppWindow = nullptr;
+        static bool isHungAppWindowInitialized = false;
+
+        if (isHungAppWindowInitialized)
+            return isHungAppWindow;
 
+        auto user32Handle = LoadLibraryA("user32.dll");
+        if (user32Handle == nullptr)
+            return nullptr;
+
+        isHungAppWindow = reinterpret_cast<IsHungAppWindowFn>(GetProcAddress(user32Handle, "IsHungAppWindow"));
+        isHungAppWindowInitialized = true;
+
+        return isHungAppWindow;
+    }
+    
     CrashMonitor::CrashMonitor(HANDLE shmHandle)
         : mShmHandle(shmHandle)
     {
@@ -123,8 +145,8 @@ namespace Crash
             else
                 return false;
         }
-        if (IsHungAppWindow)
-            return IsHungAppWindow(mAppWindowHandle);
+        if (auto isHungAppWindow = getIsHungAppWindow(); isHungAppWindow != nullptr)
+            return isHungAppWindow(mAppWindowHandle);
         else
         {
             BOOL debuggerPresent;