text: /*
   * Copyright (C) 2015 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
   */
  
  #pragma once
  
  #include <wtf/RefPtr.h>
  #include <wtf/ThreadSafeRefCounted.h>
  
  namespace WTF {
  
  // Box<T> is a reference-counted pointer to T that allocates T using FastMalloc and prepends a reference
  // count to it.
  template<typename T>
  class Box {
      WTF_MAKE_FAST_ALLOCATED;
  public:
      Box() = default;
      Box(Box&&) = default;
      Box(const Box&) = default;
  
      Box(std::nullptr_t)
      {
      }
  
      Box& operator=(Box&&) = default;
      Box& operator=(const Box&) = default;
  
      template<typename... Arguments>
      static Box create(Arguments&&... arguments)
      {
          Box result;
          result.m_data = adoptRef(new Data(std::forward<Arguments>(arguments)...));
          return result;
      }
  
      T* get() const { return &m_data->value; }
  
      T& operator*() const { return m_data->value; }
      T* operator->() const { return &m_data->value; }
  
      explicit operator bool() const { return static_cast<bool>(m_data); }
      
  private:
      struct Data : ThreadSafeRefCounted<Data> {
          template<typename... Arguments>
          Data(Arguments&&... arguments)
              : value(std::forward<Arguments>(arguments)...)
          {
          }
          
          T value;
      };
  
      RefPtr<Data> m_data;
  };
  
  } // namespace WTF
  
  using WTF::Box;
  