blocxx

RefCountedPimpl.hpp

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00002 * Copyright (C) 2005, Quest Software, Inc. All rights reserved.
00003 * Copyright (C) 2006, Novell, Inc. All rights reserved.
00004 * 
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00032 
00033 
00034 #ifndef REF_COUNTED_PIMPL_HPP
00035 #define REF_COUNTED_PIMPL_HPP
00036 
00038 
00039 #include "blocxx/BLOCXX_config.h"
00040 #include "blocxx/IntrusiveCountableBase.hpp"
00041 #include "blocxx/IntrusiveReference.hpp"
00042 
00043 namespace BLOCXX_NAMESPACE
00044 {
00045 
00063    template <typename Impl>
00064    class RefCountedPimpl
00065    {
00066    protected:
00067       // These member functions will only get instantiated where they are
00068       // used -- in the implementation code for the class.  Thus the full
00069       // definition of Impl need not be visible in code that merely uses
00070       // a class derived from RefCountedPimpl<Impl>.
00071       // Unfortunately this is not the case for any classes which need
00072       // to be exported from a DLL (using __declspec(dllexport)) on
00073       // windows. If that is the case, then the definition does need
00074       // to be visible because every member function of the exported
00075       // class and it's base classes will be instantiated.
00076 
00078       // 
00079       RefCountedPimpl()
00080       : m_impl(0)
00081       {
00082       }
00083 
00085       //
00086       RefCountedPimpl(Impl * p)
00087       : m_impl(p)
00088       {
00089       }
00090 
00093       //
00094       RefCountedPimpl(IntrusiveCountableBase * p)
00095       : m_impl(p)
00096       {
00097       }
00098 
00100       //
00101       Impl * pimpl() const
00102       {
00103          return static_cast<Impl *>(m_impl.getPtr());
00104       }
00105 
00107       //
00108       bool null() const
00109       {
00110          return !m_impl;
00111       }
00112 
00113    private:
00114       // IntrusiveCountableBase is used instead of Impl because we want to
00115       // be able to hide the full definition of Impl while still having
00116       // the implicit copy ctor, copy assignment, and dtor available.
00117       //
00118       IntrusiveReference<IntrusiveCountableBase> m_impl;
00119    };
00120 
00121 }
00122 
00123 #endif