IntSetCursor() don't BSOD in low-resource conditions

reactos/subsys/win32k/ntuser

diff -u -r1.2 -r1.3
--- cursoricon.c	12 Dec 2004 17:56:52 -0000	1.2
+++ cursoricon.c	18 Dec 2004 23:55:26 -0000	1.3
@@ -16,7 +16,7 @@

  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

-/* $Id: cursoricon.c,v 1.2 2004/12/12 17:56:52 weiden Exp $ */

+/* $Id: cursoricon.c,v 1.3 2004/12/18 23:55:26 royce Exp $ */

 #include <w32k.h>
 
 PCURICON_OBJECT FASTCALL

@@ -81,8 +81,10 @@

       DC_UnlockDc(Screen);
       
       BitmapObj = BITMAPOBJ_LockBitmap(dcbmp);

-      /* FIXME - BitmapObj can be NULL!!!!! */

+      if ( !BitmapObj )
+        return (HCURSOR)0;

       SurfObj = &BitmapObj->SurfObj;

+      ASSERT(SurfObj);

    }
   
    if (!NewCursor && (CurInfo->CurrentCursorObject || ForceChange))

@@ -164,7 +166,12 @@

               MaskBmpObj->SurfObj.sizlBitmap, abs(MaskBmpObj->SurfObj.lDelta),
               MaskBmpObj->SurfObj.iBitmapFormat, BMF_TOPDOWN,
               NULL);

-            ASSERT(hMask);

+            if ( !hMask )
+            {
+              BITMAPOBJ_UnlockBitmap(NewCursor->IconInfo.hbmMask);
+              BITMAPOBJ_UnlockBitmap(dcbmp);
+              return (HCURSOR)0;
+            }

             soMask = EngLockSurface((HSURF)hMask);
             EngCopyBits(soMask, &MaskBmpObj->SurfObj, NULL, NULL,
               &DestRect, &SourcePoint);