SharedLibraryReference.hpp

Go to the documentation of this file.

/*******************************************************************************
* Copyright (C) 2005, Vintela, Inc. All rights reserved.
* Copyright (C) 2006, Novell, Inc. All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice,
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright
*       notice, this list of conditions and the following disclaimer in the
*       documentation and/or other materials provided with the distribution.
*     * Neither the name of 
*       Vintela, Inc., 
*       nor Novell, Inc., 
*       nor the names of its contributors or employees may be used to 
*       endorse or promote products derived from this software without 
*       specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*******************************************************************************/
 
 
#ifndef BLOCXX_SHARED_LIBRARY_REFERENCE_HPP_
#define BLOCXX_SHARED_LIBRARY_REFERENCE_HPP_
#include "blocxx/BLOCXX_config.h"
#include "blocxx/SharedLibrary.hpp"
 
namespace BLOCXX_NAMESPACE
{
 
template <class T>
class SharedLibraryReference
{
public:
   typedef T element_type;
 
   SharedLibraryReference(const SharedLibraryRef& lib, const T& obj)
   : m_sharedLib(lib), m_obj(obj)
   {}
   SharedLibraryReference(const SharedLibraryRef& lib, typename T::element_type* obj)
   : m_sharedLib(lib), m_obj(T(obj))
   {}
   SharedLibraryReference(const SharedLibraryReference<T>& arg)
   : m_sharedLib(arg.m_sharedLib), m_obj(arg.m_obj)
   {
   }
   /* construct out of a reference to a derived type.  U should be
   derived from T */
   template <class U>
   SharedLibraryReference(const SharedLibraryReference<U>& arg)
   : m_sharedLib(arg.m_sharedLib), m_obj(arg.m_obj)
   {
   }
   SharedLibraryReference()
   : m_sharedLib(), m_obj()
   {}
   SharedLibraryReference<T>& operator=(const SharedLibraryReference<T>& arg)
   {
      m_obj = arg.m_obj;
      m_sharedLib = arg.m_sharedLib;
      return *this;
   }
   ~SharedLibraryReference()
   {
      try
      {
         m_obj = 0;
         m_sharedLib = 0;
      }
      catch (...)
      {
         // don't let exceptions escape
      }
   }
   SharedLibraryRef getLibRef() const
   {
      return m_sharedLib;
   }
   typename T::element_type* operator->() const
   {
      return &*m_obj;
   }
   T get() const
   {
      return m_obj;
   }
   
   typedef T SharedLibraryReference::*safe_bool;
   operator safe_bool () const
      {  return (m_obj) ? &SharedLibraryReference::m_obj : 0; }
   bool operator!() const
      {  return !m_obj; }
   void setNull()
   {
      m_obj = 0;
      m_sharedLib = 0;
   }
   
   template <class U>
   SharedLibraryReference<U> cast_to() const
   {
      SharedLibraryReference<U> rval;
      rval.m_sharedLib = m_sharedLib;
      rval.m_obj = m_obj.cast_to<U>();
      return rval;
   }
 
   BLOCXX_DEPRECATED bool isNull() const // in 3.1.0
   {
      return !m_obj;
   }
 
#if !defined(__GNUC__) || __GNUC__ > 2 // causes gcc 2.95 to ICE
   /* This is so cast_to will work */
   template <class U> friend class SharedLibraryReference;
 
private:
#endif
 
   SharedLibraryRef m_sharedLib;
   T m_obj;
};
 
} // end namespace BLOCXX_NAMESPACE
 
#endif