/*
 * Copyright 2006-2008 The FLWOR Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ZORBA_SMARTPTR_API_H
#define ZORBA_SMARTPTR_API_H

#include <zorba/config.h>

namespace zorba {

class ZORBA_DLL_PUBLIC SmartObject
{
protected:
  mutable unsigned int  theRefCount;

public:
  SmartObject() : theRefCount(0) { }

  SmartObject(const SmartObject&) : theRefCount(0) { }

  virtual ~SmartObject();

  virtual void free();

  long getRefCount() const { return theRefCount; }

  void addReference() const { ++theRefCount; }

  void removeReference () {
    if (--theRefCount == 0) 
      free();
  }

  SmartObject& operator=(const SmartObject&) { return *this; }
}; /* class SmartObject */

template<class T>
class SmartPtr 
{
protected:
  T  *p;

  void init() {
    if (p != 0) p->addReference();
  }

  template <class otherT> SmartPtr& 
  assign (const SmartPtr<otherT>& rhs) {
    if (p != rhs.get())
    {
      if (p) p->removeReference();
      p = static_cast<T*>(rhs.get());
      init();
    }
    return *this;
  }

public:
  SmartPtr(T* realPtr = 0) : p(realPtr) {
    init(); 
  }

  SmartPtr(SmartPtr const& rhs) : p(rhs.get()) {
    init();
  }

  ~SmartPtr() {
    if (p)
      p->removeReference();
    p = 0;
  }

  bool isNull () const        { return p == 0; }

  T* get() const             { return p; }

  operator T* ()              { return get(); }
  operator const T * () const { return get(); }

  T* operator->() const       { return p; } 
  T& operator*() const        { return *p; } 

  bool operator==(SmartPtr const& h) const  { return p == h.p; }
  bool operator!=(SmartPtr const& h) const  { return p != h.p; }
  bool operator==(T const* pp) const        { return p == pp; } 
  bool operator!=(T const* pp) const        { return p != pp; }
  bool operator<(const SmartPtr& h) const   { return p < h.p; }

  SmartPtr& operator=(SmartPtr const& rhs) {
    return assign (rhs);
  }

  template <class otherT> SmartPtr& operator=(SmartPtr<otherT> const& rhs) {
    return assign (rhs);
  }

}; // SmartPtr

} // namespace zorba
#endif /* ZORBA_SMARTPTR_API_H */
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