ossimReferenced.h

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/* -*-c++-*- libossim - Copyright (C) since 2004 Garrett Potts 
 * LICENSE: MIT
 * Author: Garrett Potts
*/
#ifndef ossimReferenced_HEADER
#define ossimReferenced_HEADER
#include <ossim/base/ossimConstants.h>

#include <atomic>
#include <mutex>

class OSSIMDLLEXPORT ossimReferenced
{
 public:
   ossimReferenced()
   : m_refCount(0)
      {}
   
   ossimReferenced(const ossimReferenced&)
   : m_refCount(0)
   {}
   inline ossimReferenced& operator = (const ossimReferenced&) { return *this; }
   

   inline void ref() const;
   
   inline void unref() const;
   
   inline void unref_nodelete() const 
   { 
     // std::lock_guard<std::mutex> lock(theRefMutex); 
     --m_refCount;
   }
   
   inline int referenceCount() const { return m_refCount.load(); }
   
   
 protected:
   virtual ~ossimReferenced();

 private:
    mutable std::atomic_int      m_refCount;
};

inline void ossimReferenced::ref() const
{
  ++m_refCount;
}

inline void ossimReferenced::unref() const
{
  bool needDelete = false;
  {
    // fetch_sub should return the value before subtraction.
    // so if 1 was before the subtraction that means it should
    // be zero after the subtraction so we will test <=1
    needDelete = m_refCount.fetch_sub(1) <= 1;
  }

  if (needDelete)
  {
    delete this;
  }
}

#endif