text: /*
   *  Copyright (C) 2006, 2007, 2008, 2009 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.
   *
   */
  
  #ifndef WTF_OwnPtr_h
  #define WTF_OwnPtr_h
  
  #include "Assertions.h"
  #include "Noncopyable.h"
  #include "OwnPtrCommon.h"
  #include "TypeTraits.h"
  #include <algorithm>
  #include <memory>
  
  namespace WTF {
  
      // Unlike most of our smart pointers, OwnPtr can take either the pointer type or the pointed-to type.
  
      template <typename T> class PassOwnPtr;
  
      template <typename T> class OwnPtr : public Noncopyable {
      public:
          typedef typename RemovePointer<T>::Type ValueType;
          typedef ValueType* PtrType;
  
          explicit OwnPtr(PtrType ptr = 0) : m_ptr(ptr) { }
          OwnPtr(std::auto_ptr<ValueType> autoPtr) : m_ptr(autoPtr.release()) { }
          // See comment in PassOwnPtr.h for why this takes a const reference.
          template <typename U> OwnPtr(const PassOwnPtr<U>& o);
  
          // This copy constructor is used implicitly by gcc when it generates
          // transients for assigning a PassOwnPtr<T> object to a stack-allocated
          // OwnPtr<T> object.  It should never be called explicitly and gcc
          // should optimize away the constructor when generating code.
          OwnPtr(const OwnPtr<ValueType>& o);
  
          ~OwnPtr() { deleteOwnedPtr(m_ptr); }
  
          PtrType get() const { return m_ptr; }
          PtrType release() { PtrType ptr = m_ptr; m_ptr = 0; return ptr; }
  
          // FIXME: This should be renamed to adopt. 
          void set(PtrType ptr) { ASSERT(!ptr || m_ptr != ptr); deleteOwnedPtr(m_ptr); m_ptr = ptr; }
  
          void adopt(std::auto_ptr<ValueType> autoPtr) { ASSERT(!autoPtr.get() || m_ptr != autoPtr.get()); deleteOwnedPtr(m_ptr); m_ptr = autoPtr.release(); }
  
          void clear() { deleteOwnedPtr(m_ptr); m_ptr = 0; }
  
          ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }
          PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }
  
          bool operator!() const { return !m_ptr; }
  
          // This conversion operator allows implicit conversion to bool but not to other integer types.
          typedef PtrType OwnPtr::*UnspecifiedBoolType;
          operator UnspecifiedBoolType() const { return m_ptr ? &OwnPtr::m_ptr : 0; }
  
          OwnPtr& operator=(const PassOwnPtr<T>&);
          template <typename U> OwnPtr& operator=(const PassOwnPtr<U>&);
  
          void swap(OwnPtr& o) { std::swap(m_ptr, o.m_ptr); }
  
      private:
          PtrType m_ptr;
      };
  
      template <typename T> template <typename U> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<U>& o)
          : m_ptr(o.release())
      {
      }
  
      template <typename T> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<T>& o)
      {
          T* ptr = m_ptr;
          m_ptr = o.release();
          ASSERT(!ptr || m_ptr != ptr);
          if (ptr)
              deleteOwnedPtr(ptr);
          return *this;
      }
  
      template <typename T> template <typename U> inline OwnPtr<T>& OwnPtr<T>::operator=(const PassOwnPtr<U>& o)
      {
          T* ptr = m_ptr;
          m_ptr = o.release();
          ASSERT(!ptr || m_ptr != ptr);
          if (ptr)
              deleteOwnedPtr(ptr);
          return *this;
      }
  
      template <typename T> inline void swap(OwnPtr<T>& a, OwnPtr<T>& b)
      {
          a.swap(b);
      }
  
      template <typename T, typename U> inline bool operator==(const OwnPtr<T>& a, U* b)
      {
          return a.get() == b; 
      }
  
      template <typename T, typename U> inline bool operator==(T* a, const OwnPtr<U>& b) 
      {
          return a == b.get(); 
      }
  
      template <typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, U* b)
      {
          return a.get() != b; 
      }
  
      template <typename T, typename U> inline bool operator!=(T* a, const OwnPtr<U>& b)
      {
          return a != b.get(); 
      }
  
      template <typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)
      {
          return p.get();
      }
  
  } // namespace WTF
  
  using WTF::OwnPtr;
  
  #endif // WTF_OwnPtr_h
  