text: /*
   *  Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
   *  Copyright (C) 2008 Collabora Ltd.
   *  Copyright (C) 2009 Martin Robinson
   *
   *  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_GRefPtr_h
  #define WTF_GRefPtr_h
  
  #if USE(GLIB)
  
  #include <wtf/HashTraits.h>
  #include <algorithm>
  #include <glib.h>
  
  extern "C" void g_object_unref(gpointer);
  extern "C" gpointer g_object_ref_sink(gpointer);
  
  namespace WTF {
  
  enum GRefPtrAdoptType { GRefPtrAdopt };
  template <typename T> inline T* refGPtr(T*);
  template <typename T> inline void derefGPtr(T*);
  template <typename T> class GRefPtr;
  template <typename T> GRefPtr<T> adoptGRef(T*);
  
  template <typename T> class GRefPtr {
  public:
      typedef T ValueType;
      typedef ValueType* PtrType;
  
      GRefPtr() : m_ptr(0) { }
  
      GRefPtr(T* ptr)
          : m_ptr(ptr)
      {
          if (ptr)
              refGPtr(ptr);
      }
  
      GRefPtr(const GRefPtr& o)
          : m_ptr(o.m_ptr)
      {
          if (T* ptr = m_ptr)
              refGPtr(ptr);
      }
  
      template <typename U> GRefPtr(const GRefPtr<U>& o)
          : m_ptr(o.get())
      {
          if (T* ptr = m_ptr)
              refGPtr(ptr);
      }
  
      GRefPtr(GRefPtr&& o) : m_ptr(o.leakRef()) { }
      template <typename U> GRefPtr(GRefPtr<U>&& o) : m_ptr(o.leakRef()) { }
  
      ~GRefPtr()
      {
          if (T* ptr = m_ptr)
              derefGPtr(ptr);
      }
  
      void clear()
      {
          T* ptr = m_ptr;
          m_ptr = 0;
          if (ptr)
              derefGPtr(ptr);
      }
  
      T* leakRef() WARN_UNUSED_RETURN
      {
          T* ptr = m_ptr;
          m_ptr = 0;
          return ptr;
      }
  
      T*& outPtr()
      {
          ASSERT(!m_ptr);
          return m_ptr;
      }
  
      // Hash table deleted values, which are only constructed and never copied or destroyed.
      GRefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
      bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
  
      T* get() const { return m_ptr; }
      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* GRefPtr::*UnspecifiedBoolType;
      operator UnspecifiedBoolType() const { return m_ptr ? &GRefPtr::m_ptr : 0; }
  
      GRefPtr& operator=(const GRefPtr&);
      GRefPtr& operator=(GRefPtr&&);
      GRefPtr& operator=(T*);
      template <typename U> GRefPtr& operator=(const GRefPtr<U>&);
  
      void swap(GRefPtr&);
      friend GRefPtr adoptGRef<T>(T*);
  
  private:
      static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
      // Adopting constructor.
      GRefPtr(T* ptr, GRefPtrAdoptType) : m_ptr(ptr) {}
  
      T* m_ptr;
  };
  
  template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(const GRefPtr<T>& o)
  {
      T* optr = o.get();
      if (optr)
          refGPtr(optr);
      T* ptr = m_ptr;
      m_ptr = optr;
      if (ptr)
          derefGPtr(ptr);
      return *this;
  }
  
  template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(GRefPtr<T>&& o)
  {
      GRefPtr ptr = WTFMove(o);
      swap(ptr);
      return *this;
  }
  
  template <typename T> inline GRefPtr<T>& GRefPtr<T>::operator=(T* optr)
  {
      T* ptr = m_ptr;
      if (optr)
          refGPtr(optr);
      m_ptr = optr;
      if (ptr)
          derefGPtr(ptr);
      return *this;
  }
  
  template <class T> inline void GRefPtr<T>::swap(GRefPtr<T>& o)
  {
      std::swap(m_ptr, o.m_ptr);
  }
  
  template <class T> inline void swap(GRefPtr<T>& a, GRefPtr<T>& b)
  {
      a.swap(b);
  }
  
  template <typename T, typename U> inline bool operator==(const GRefPtr<T>& a, const GRefPtr<U>& b)
  {
      return a.get() == b.get();
  }
  
  template <typename T, typename U> inline bool operator==(const GRefPtr<T>& a, U* b)
  {
      return a.get() == b;
  }
  
  template <typename T, typename U> inline bool operator==(T* a, const GRefPtr<U>& b)
  {
      return a == b.get();
  }
  
  template <typename T, typename U> inline bool operator!=(const GRefPtr<T>& a, const GRefPtr<U>& b)
  {
      return a.get() != b.get();
  }
  
  template <typename T, typename U> inline bool operator!=(const GRefPtr<T>& a, U* b)
  {
      return a.get() != b;
  }
  
  template <typename T, typename U> inline bool operator!=(T* a, const GRefPtr<U>& b)
  {
      return a != b.get();
  }
  
  template <typename T, typename U> inline GRefPtr<T> static_pointer_cast(const GRefPtr<U>& p)
  {
      return GRefPtr<T>(static_cast<T*>(p.get()));
  }
  
  template <typename T, typename U> inline GRefPtr<T> const_pointer_cast(const GRefPtr<U>& p)
  {
      return GRefPtr<T>(const_cast<T*>(p.get()));
  }
  
  template <typename T> struct IsSmartPtr<GRefPtr<T>> {
      static const bool value = true;
  };
  
  template <typename T> GRefPtr<T> adoptGRef(T* p)
  {
      return GRefPtr<T>(p, GRefPtrAdopt);
  }
  
  template <> WTF_EXPORT_PRIVATE GHashTable* refGPtr(GHashTable* ptr);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GHashTable* ptr);
  template <> WTF_EXPORT_PRIVATE GMainContext* refGPtr(GMainContext* ptr);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GMainContext* ptr);
  template <> WTF_EXPORT_PRIVATE GMainLoop* refGPtr(GMainLoop* ptr);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GMainLoop* ptr);
  template <> WTF_EXPORT_PRIVATE GVariant* refGPtr(GVariant* ptr);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GVariant* ptr);
  template <> WTF_EXPORT_PRIVATE GVariantBuilder* refGPtr(GVariantBuilder* ptr);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GVariantBuilder* ptr);
  template <> WTF_EXPORT_PRIVATE GSource* refGPtr(GSource* ptr);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GSource* ptr);
  template <> WTF_EXPORT_PRIVATE GPtrArray* refGPtr(GPtrArray*);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GPtrArray*);
  template <> WTF_EXPORT_PRIVATE GByteArray* refGPtr(GByteArray*);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GByteArray*);
  template <> WTF_EXPORT_PRIVATE GBytes* refGPtr(GBytes*);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GBytes*);
  template <> WTF_EXPORT_PRIVATE GClosure* refGPtr(GClosure*);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GClosure*);
  template <> WTF_EXPORT_PRIVATE GRegex* refGPtr(GRegex*);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GRegex*);
  template <> WTF_EXPORT_PRIVATE GMappedFile* refGPtr(GMappedFile*);
  template <> WTF_EXPORT_PRIVATE void derefGPtr(GMappedFile*);
  
  template <typename T> inline T* refGPtr(T* ptr)
  {
      if (ptr)
          g_object_ref_sink(ptr);
      return ptr;
  }
  
  template <typename T> inline void derefGPtr(T* ptr)
  {
      if (ptr)
          g_object_unref(ptr);
  }
  
  template<typename P> struct DefaultHash<GRefPtr<P>> { typedef PtrHash<GRefPtr<P>> Hash; };
  
  template<typename P> struct HashTraits<GRefPtr<P>> : SimpleClassHashTraits<GRefPtr<P>> {
      static P* emptyValue() { return nullptr; }
  
      typedef P* PeekType;
      static PeekType peek(const GRefPtr<P>& value) { return value.get(); }
      static PeekType peek(P* value) { return value; }
  
      static void customDeleteBucket(GRefPtr<P>& value)
      {
          // See unique_ptr's customDeleteBucket() for an explanation.
          ASSERT(!SimpleClassHashTraits<GRefPtr<P>>::isDeletedValue(value));
          auto valueToBeDestroyed = WTFMove(value);
          SimpleClassHashTraits<GRefPtr<P>>::constructDeletedValue(value);
      }
  };
  
  } // namespace WTF
  
  using WTF::GRefPtr;
  using WTF::adoptGRef;
  
  #endif // USE(GLIB)
  
  #endif // WTF_GRefPtr_h
  