From 0a9026f76e7c5ca73d8015d094863f800f415be5 Mon Sep 17 00:00:00 2001
From: Thomas Bluemel <thomas@reactsoft.com>
Date: Sat, 17 Nov 2007 06:50:23 +0000
Subject: [PATCH] Optimize IsChild() to use the desktop heap instead of calling
 win32k

svn path=/trunk/; revision=30519
---
 reactos/dll/win32/user32/windows/window.c | 42 +++++++++++++++++------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/reactos/dll/win32/user32/windows/window.c b/reactos/dll/win32/user32/windows/window.c
index fc3f2f7ebe9..559ece8439c 100644
--- a/reactos/dll/win32/user32/windows/window.c
+++ b/reactos/dll/win32/user32/windows/window.c
@@ -1252,18 +1252,40 @@ BOOL STDCALL
 IsChild(HWND hWndParent,
 	HWND hWnd)
 {
-   if (! IsWindow(hWndParent) || ! IsWindow(hWnd))
-   {
-       return FALSE;
-   }
+    PWINDOW WndParent, Wnd;
+    BOOL Ret = FALSE;
 
-   do
-   {
-      hWnd = (HWND)NtUserGetWindowLong(hWnd, GWL_HWNDPARENT, FALSE);
-   }
-   while (hWnd != NULL && hWnd != hWndParent);
+    WndParent = ValidateHwnd(hWndParent);
+    if (!WndParent)
+        return FALSE;
+    Wnd = ValidateHwnd(hWnd);
+    if (!Wnd)
+        return FALSE;
 
-   return hWnd == hWndParent;
+    _SEH_TRY
+    {
+        while (Wnd != NULL)
+        {
+            if (Wnd->Parent != NULL)
+            {
+                Wnd = DesktopPtrToUser(Wnd->Parent);
+                if (Wnd == WndParent)
+                {
+                    Ret = TRUE;
+                    break;
+                }
+            }
+            else
+                break;
+        }
+    }
+    _SEH_HANDLE
+    {
+        /* Do nothing */
+    }
+    _SEH_END;
+
+    return Ret;
 }