Check if DC is busy before deleting it.

include/dce.h

@@ -53,5 +53,6 @@ extern void  DCE_FreeWindowDCE( WND* );
 extern INT16 DCE_ExcludeRgn( HDC, WND*, HRGN );
 extern HRGN DCE_GetVisRgn( HWND, WORD, HWND, WORD );
 extern BOOL DCE_InvalidateDCE( WND*, const RECT* );
+extern BOOL DCE_IsDCBusy(HDC hdc);
 
 #endif  /* __WINE_DCE_H */

objects/dc.c

@@ -657,7 +657,20 @@ BOOL16 WINAPI DeleteDC16( HDC16 hdc )
  */
 BOOL WINAPI DeleteDC( HDC hdc )
 {
-    DC * dc = (DC *) GDI_GetObjPtr( hdc, DC_MAGIC );
+    DC * dc;
+
+    /*
+     * Windows will not let you delete a DC that is busy
+     * (between GetDC and ReleaseDC)
+     */
+    if (DCE_IsDCBusy(hdc))
+    {
+      WARN(dc, " Application trying to delete a busy DC\n");
+      return TRUE;
+    }
+
+    dc = (DC *) GDI_GetObjPtr( hdc, DC_MAGIC );
+
     if (!dc) return FALSE;
 
     TRACE(dc, "%04x\n", hdc );

windows/dce.c

@@ -627,6 +627,35 @@ INT16 DCE_ExcludeRgn( HDC hDC, WND* wnd, HRGN hRgn )
   return ExtSelectClipRgn( hDC, hRgn, RGN_DIFF );
 }
 
+/***********************************************************************
+ *           DCE_IsDCBusy
+ * 
+ *  Utility function to determine if a particular DC is currently
+ *  in a busy state..
+ */
+BOOL DCE_IsDCBusy(HDC hdc)
+{
+    DCE* dce;
+    BOOL isBusy = FALSE;
+
+    WIN_LockWnds();
+    dce = firstDCE;
+            
+    while (dce && (dce->hDC != hdc)) dce = dce->next;
+
+    if ( dce ) 
+    {
+      if ( dce->DCXflags & DCX_DCEBUSY )
+      {
+	isBusy = TRUE;
+      }
+    }
+
+    WIN_UnlockWnds();
+
+    return isBusy;
+}
+
 /***********************************************************************
  *           GetDCEx16    (USER.359)
  */