From 7909f7d776385f2dd17d51bf994e57d7993cf3f8 Mon Sep 17 00:00:00 2001
From: Oleg Dubinskiy <oleg.dubinskij30@gmail.com>
Date: Mon, 23 Dec 2024 22:37:23 +0100
Subject: [PATCH] [USER32] Implement IsServerSideWindow (undocumented)
 Implement IsServerSideWindow function in user32. It checks whether a window
 has a window procedure that resides in kernel mode and returns a boolean
 condition based on the appropriate internal window state flag
 (WNDS_SERVERSIDEWINDOWPROC). This function is not officially documented by
 Microsoft, but fortunately it has unofficial documentation at
 http://undoc.airesoft.co.uk/user32.dll/IsServerSideWindow.php. Required and
 used internally by uxtheme.dll from Windows XP/2003/Vista/7/etc. The log
 spams with it a lot, when using uxtheme.dll from Windows in ReactOS.
 CORE-19946

---
 win32ss/user/user32/misc/stubs.c     |  9 --------
 win32ss/user/user32/windows/window.c | 31 ++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/win32ss/user/user32/misc/stubs.c b/win32ss/user/user32/misc/stubs.c
index bb1754b781f..0936064e19c 100644
--- a/win32ss/user/user32/misc/stubs.c
+++ b/win32ss/user/user32/misc/stubs.c
@@ -432,15 +432,6 @@ WORD WINAPI InitializeWin32EntryTable(UCHAR* EntryTablePlus0x1000)
   return FALSE;
 }
 
-/*
- * @unimplemented
- */
-BOOL WINAPI IsServerSideWindow(HWND wnd)
-{
-  UNIMPLEMENTED;
-  return FALSE;
-}
-
 /*
  * @unimplemented
  */
diff --git a/win32ss/user/user32/windows/window.c b/win32ss/user/user32/windows/window.c
index dfe06a349c5..76478f3687f 100644
--- a/win32ss/user/user32/windows/window.c
+++ b/win32ss/user/user32/windows/window.c
@@ -1512,6 +1512,37 @@ IsIconic(HWND hWnd)
 }
 
 
+/**
+ * @brief
+ * IsServerSideWindow
+ *
+ * Checks whether a window has a window procedure that resides in kernel mode.
+ *
+ * @param[in] hWnd
+ * A handle to the window to be checked.
+ *
+ * @return
+ * TRUE if the window has a window procedure that resides in kernel mode,
+ * FALSE otherwise.
+ *
+ * @remarks
+ * Undocumented, see http://undoc.airesoft.co.uk/user32.dll/IsServerSideWindow.php
+ * (unofficial documentation).
+ */
+BOOL
+WINAPI
+IsServerSideWindow(
+    _In_ HWND hWnd)
+{
+    PWND Wnd = ValidateHwnd(hWnd);
+
+    if (Wnd != NULL)
+        return (Wnd->state & WNDS_SERVERSIDEWINDOWPROC) != 0;
+
+    return FALSE;
+}
+
+
 /*
  * @implemented
  */