text: /*
   *  Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
   *
   *  This library is free software; you can redistribute it and/or
   *  modify it under the terms of the GNU Library General Public
   *  License as published by the Free Software Foundation; either
   *  version 2 of the License, or (at your option) any later version.
   *
   *  This library is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  Library General Public License for more details.
   *
   *  You should have received a copy of the GNU Library General Public License
   *  along with this library; see the file COPYING.LIB.  If not, write to
   *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   *  Boston, MA 02110-1301, USA.
   *
   */
  
  // RefPtr and PassRefPtr are documented at http://webkit.org/coding/RefPtr.html
  
  #ifndef WTF_RefPtr_h
  #define WTF_RefPtr_h
  
  #include <algorithm>
  #include "FastAllocBase.h"
  #include "PassRefPtr.h"
  
  namespace WTF {
  
      enum PlacementNewAdoptType { PlacementNewAdopt };
  
      template<typename T> class PassRefPtr;
      template<typename T> class NonNullPassRefPtr;
  
      enum HashTableDeletedValueType { HashTableDeletedValue };
  
      template<typename T> class RefPtr {
          WTF_MAKE_FAST_ALLOCATED;
      public:
          ALWAYS_INLINE RefPtr() : m_ptr(0) { }
          ALWAYS_INLINE RefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
          ALWAYS_INLINE RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { refIfNotNull(m_ptr); }
          template<typename U> RefPtr(const RefPtr<U>& o) : m_ptr(o.get()) { refIfNotNull(m_ptr); }
  
          // See comments in PassRefPtr.h for an explanation of why these takes const references.
          template<typename U> RefPtr(const PassRefPtr<U>&);
          template<typename U> RefPtr(const NonNullPassRefPtr<U>&);
  
          // Special constructor for cases where we overwrite an object in place.
          ALWAYS_INLINE RefPtr(PlacementNewAdoptType) { }
  
          // Hash table deleted values, which are only constructed and never copied or destroyed.
          RefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
          bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
  
          ALWAYS_INLINE ~RefPtr() { derefIfNotNull(m_ptr); }
  
          T* get() const { return m_ptr; }
          
          void clear();
          PassRefPtr<T> release() { PassRefPtr<T> tmp = adoptRef(m_ptr); m_ptr = 0; return tmp; }
  
          T& operator*() const { return *m_ptr; }
          ALWAYS_INLINE T* operator->() const { return m_ptr; }
          
          bool operator!() const { return !m_ptr; }
      
          // This conversion operator allows implicit conversion to bool but not to other integer types.
          typedef T* (RefPtr::*UnspecifiedBoolType);
          operator UnspecifiedBoolType() const { return m_ptr ? &RefPtr::m_ptr : 0; }
          
          RefPtr& operator=(const RefPtr&);
          RefPtr& operator=(T*);
          RefPtr& operator=(const PassRefPtr<T>&);
          RefPtr& operator=(const NonNullPassRefPtr<T>&);
  #if !HAVE(NULLPTR)
          RefPtr& operator=(std::nullptr_t) { clear(); return *this; }
  #endif
          template<typename U> RefPtr& operator=(const RefPtr<U>&);
          template<typename U> RefPtr& operator=(const PassRefPtr<U>&);
          template<typename U> RefPtr& operator=(const NonNullPassRefPtr<U>&);
  
          void swap(RefPtr&);
  
          static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
  
      private:
          T* m_ptr;
      };
      
      template<typename T> template<typename U> inline RefPtr<T>::RefPtr(const PassRefPtr<U>& o)
          : m_ptr(o.leakRef())
      {
      }
  
      template<typename T> template<typename U> inline RefPtr<T>::RefPtr(const NonNullPassRefPtr<U>& o)
          : m_ptr(o.leakRef())
      {
      }
  
      template<typename T> inline void RefPtr<T>::clear()
      {
          T* ptr = m_ptr;
          m_ptr = 0;
          derefIfNotNull(ptr);
      }
  
      template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<T>& o)
      {
          T* optr = o.get();
          refIfNotNull(optr);
          T* ptr = m_ptr;
          m_ptr = optr;
          derefIfNotNull(ptr);
          return *this;
      }
      
      template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<U>& o)
      {
          T* optr = o.get();
          refIfNotNull(optr);
          T* ptr = m_ptr;
          m_ptr = optr;
          derefIfNotNull(ptr);
          return *this;
      }
      
      template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(T* optr)
      {
          refIfNotNull(optr);
          T* ptr = m_ptr;
          m_ptr = optr;
          derefIfNotNull(ptr);
          return *this;
      }
  
      template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<T>& o)
      {
          T* ptr = m_ptr;
          m_ptr = o.leakRef();
          derefIfNotNull(ptr);
          return *this;
      }
  
      template<typename T> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<T>& o)
      {
          T* ptr = m_ptr;
          m_ptr = o.leakRef();
          derefIfNotNull(ptr);
          return *this;
      }
  
      template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<U>& o)
      {
          T* ptr = m_ptr;
          m_ptr = o.leakRef();
          derefIfNotNull(ptr);
          return *this;
      }
  
      template<typename T> template<typename U> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<U>& o)
      {
          T* ptr = m_ptr;
          m_ptr = o.leakRef();
          derefIfNotNull(ptr);
          return *this;
      }
  
      template<class T> inline void RefPtr<T>::swap(RefPtr<T>& o)
      {
          std::swap(m_ptr, o.m_ptr);
      }
  
      template<class T> inline void swap(RefPtr<T>& a, RefPtr<T>& b)
      {
          a.swap(b);
      }
  
      template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, const RefPtr<U>& b)
      { 
          return a.get() == b.get(); 
      }
  
      template<typename T, typename U> inline bool operator==(const RefPtr<T>& a, U* b)
      { 
          return a.get() == b; 
      }
      
      template<typename T, typename U> inline bool operator==(T* a, const RefPtr<U>& b) 
      {
          return a == b.get(); 
      }
      
      template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const RefPtr<U>& b)
      { 
          return a.get() != b.get(); 
      }
  
      template<typename T, typename U> inline bool operator!=(const RefPtr<T>& a, U* b)
      {
          return a.get() != b; 
      }
  
      template<typename T, typename U> inline bool operator!=(T* a, const RefPtr<U>& b)
      { 
          return a != b.get(); 
      }
      
      template<typename T, typename U> inline RefPtr<T> static_pointer_cast(const RefPtr<U>& p)
      { 
          return RefPtr<T>(static_cast<T*>(p.get())); 
      }
  
      template<typename T, typename U> inline RefPtr<T> const_pointer_cast(const RefPtr<U>& p)
      { 
          return RefPtr<T>(const_cast<T*>(p.get())); 
      }
  
      template<typename T> inline T* getPtr(const RefPtr<T>& p)
      {
          return p.get();
      }
  
  } // namespace WTF
  
  using WTF::RefPtr;
  using WTF::static_pointer_cast;
  using WTF::const_pointer_cast;
  
  #endif // WTF_RefPtr_h
  