added wxRecursionGuard

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@22835 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/recguard.h

@@ -0,0 +1,53 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/recguard.h
+// Purpose:     declaration and implementation of wxRecursionGuard class
+// Author:      Vadim Zeitlin
+// Modified by:
+// Created:     14.08.2003
+// RCS-ID:      $Id$
+// Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_RECGUARD_H_
+#define _WX_RECGUARD_H_
+
+#include "wx/defs.h"
+
+// ----------------------------------------------------------------------------
+// wxRecursionGuardFlag is used with wxRecursionGuard
+// ----------------------------------------------------------------------------
+
+typedef int wxRecursionGuardFlag;
+
+// ----------------------------------------------------------------------------
+// wxRecursionGuard is the simplest way to protect a function from reentrancy
+// ----------------------------------------------------------------------------
+
+class WXDLLIMPEXP_BASE wxRecursionGuard
+{
+public:
+    wxRecursionGuard(wxRecursionGuardFlag& flag)
+        : m_flag(flag)
+    { 
+        m_isInside = flag++ != 0;
+    }
+
+    ~wxRecursionGuard()
+    {
+        wxASSERT_MSG( m_flag > 0, _T("unbalanced wxRecursionGuards!?") );
+
+        m_flag--;
+    }
+
+    bool IsInside() const { return m_isInside; }
+
+private:
+    wxRecursionGuardFlag& m_flag;
+
+    // true if the flag had been already set when we were created
+    bool m_isInside;
+};
+
+#endif // _WX_RECGUARD_H_
+