weak_referenceable_mixin.h

Go to the documentation of this file.

/*! \file
  \brief  weak reference and related classes
 
  \par Copyright Information
 
  Copyright (c) 2016 by The DiSTI Corporation.<br>
  11301 Corporate Blvd; Suite 100<br>
  Orlando, Florida 32817<br>
  USA<br>
  <br>
  All rights reserved.<br>
 
  This Software contains proprietary trade secrets of DiSTI and may not be
reproduced, in whole or part, in any form, or by any means of electronic,
mechanical, or otherwise, without the written permission of DiSTI.  Said
permission may be derived through the purchase of applicable DiSTI product
licenses which detail the distribution rights of this content and any
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
PARTICULAR PURPOSE, TITLE, AND NON-INFRINGEMENT, WITH REGARD TO THE SOFTWARE.
 
  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,
DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS
INFORMATION, OR ANY OTHER PECUNIARY LOSS) ARISING OUT OF THE USE OF OR
INABILITY TO USE THE SOFTWARE, EVEN IF DISTI HAS BEEN ADVISED OF THE POSSIBILITY
OF SUCH DAMAGES.  DISTI'S ENTIRE LIABILITY AND YOUR EXCLUSIVE REMEDY SHALL NOT
EXCEED FIVE DOLLARS (US$5.00).
 
  The aforementioned terms and restrictions are governed by the laws of the
State of Florida and the United States of America.
 
*/
#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:
    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 );
    }
 
    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()
        : _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