weak_referenceable_mixin.h

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/*! \file
  \brief  weak reference and related classes

  \par Copyright Information

  Copyright (c) 2016 by The DiSTI Corporation.<br>
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  <br>
  All rights reserved.<br>

  This Software contains proprietary trade secrets of DiSTI and may not be
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Derivative Works based on this or other copyrighted DiSTI Software.

  NO WARRANTY. THE SOFTWARE IS PROVIDED "AS-IS," WITHOUT WARRANTY OF ANY KIND,
AND ANY USE OF THIS SOFTWARE PRODUCT IS AT YOUR OWN RISK. TO THE MAXIMUM EXTENT
PERMITTED BY APPLICABLE LAW, DISTI AND ITS SUPPLIERS DISCLAIM ALL WARRANTIES
AND CONDITIONS, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY AND/OR FITNESS FOR A
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  LIMITATION OF LIABILITY. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW,
IN NO EVENT SHALL DISTI OR ITS SUPPLIERS BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
INDIRECT, OR CONSEQUENTIAL DAMAGES WHATSOEVER (INCLUDING, WITHOUT LIMITATION,
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*/
#ifndef INCLUDED_WEAK_REFERENCEABLE_MIXIN_H
#define INCLUDED_WEAK_REFERENCEABLE_MIXIN_H

#include "dynamic_array.h"
#include "gls_cpp_lang_support.h"
#include "weak_reference.h"

namespace disti
{
/** utility helper mixin class for simplifying implementing WeakReferenceable.
      * Classes that want to implement WeakReferenceable can simply inherit this class 
      */
class WeakReferenceableMixin : virtual public WeakReferenceable
{
public:
    /** \see WeakReferenceable */
    void AddWeakReference( WeakReference* weakRef ) DISTI_METHOD_OVERRIDE
    {
        // reduce storage by only allocating the dynamic array when asked for a weak reference
        if( !_weakRefs )
        {
            _weakRefs = new DynamicArray<WeakReference*>();
        }

        // store the weak reference so we can notify it when we are deleted
        _weakRefs->PushBack( weakRef );
    }

    /** \see WeakReferenceable */
    void NotifyWeakReferenceDestroyed( WeakReference* ref ) DISTI_METHOD_OVERRIDE
    {
        // When a weak reference is deleted, remove it from our list so that we don't call a method on a deleted object
        // in our destructor
        if( _weakRefs )
        {
            for( unsigned int index = 0u; index < _weakRefs->Count(); ++index )
            {
                if( ref == ( *_weakRefs )[ index ] )
                {
                    _weakRefs->EraseAt( index );
                    return;
                }
            }
        }
    }

protected:
    /** constructor */
    WeakReferenceableMixin( void )
        : _weakRefs( NULL )
    {
    }

    /** destructor. Notifies all weak references that this object is being deleted */
    virtual ~WeakReferenceableMixin()
    {
        if( _weakRefs )
        {
            for( unsigned int index = 0u; index < _weakRefs->Count(); ++index )
            {
                ( *_weakRefs )[ index ]->NotifyReferentDestroyed();
            }

            delete _weakRefs;
            _weakRefs = NULL;
        }
    }

    /** pointer to array of weak refs.  Allocated on the first call to GetWeakReference() */
    DynamicArray<WeakReference*>* _weakRefs;
};

} // namespace disti

#endif