axmol/external/yasio/detail/ref_ptr.hpp

//
// Copyright (c) 2014-2020 HALX99 - All Rights Reserved
//
#ifndef YASIO__REF_PTR_HPP
#define YASIO__REF_PTR_HPP
#include <iostream>

// clang-format off
#define YASIO__DEFINE_REFERENCE_CLASS  \
private:                               \
  unsigned int __strong_refs = 1;      \
                                       \
public:                                \
  void retain() { ++__strong_refs; }   \
  void release()                       \
  {                                    \
    --__strong_refs;                   \
    if (__strong_refs == 0)            \
      delete this;                     \
  }                                    \
                                       \
private:

#define YASIO__SAFE_RELEASE(p)         \
  if (p)                               \
  (p)->release()

#define YASIO__SAFE_RELEASE_NULL(p)    \
  do                                   \
  {                                    \
    if (p)                             \
    {                                  \
      (p)->release();                  \
      (p) = nullptr;                   \
    }                                  \
  } while (0)

#define YASIO__SAFE_RETAIN(p)          \
  if (p)                               \
  (p)->retain()
// clang-format on

namespace yasio
{
namespace gc
{

// TEMPLATE CLASS ref_ptr, allow any time with functions 'retain' and 'release'
template <typename _Ty> class ref_ptr;

template <typename _Ty> class ref_ptr { // wrap an object pointer to ensure destruction
public:
  typedef ref_ptr<_Ty> _Myt;
  typedef _Ty element_type;

  explicit ref_ptr(_Ty* _Ptr = 0) throw() : ptr_(_Ptr)
  { // construct from object pointer
  }

  ref_ptr(std::nullptr_t) throw() : ptr_(0) {}

  ref_ptr(const _Myt& _Right) throw()
  { // construct by assuming pointer from _Right ref_ptr
    YASIO__SAFE_RETAIN(_Right.get());

    ptr_ = _Right.get();
  }

  template <typename _Other> ref_ptr(const ref_ptr<_Other>& _Right) throw()
  { // construct by assuming pointer from _Right
    YASIO__SAFE_RETAIN(_Right.get());

    ptr_ = (_Ty*)_Right.get();
  }

  ref_ptr(_Myt&& _Right) throw()
  {
    YASIO__SAFE_RETAIN(_Right.get());

    ptr_ = (_Ty*)_Right.get();
  }

  template <typename _Other> ref_ptr(ref_ptr<_Other>&& _Right) throw()
  { // construct by assuming pointer from _Right
    YASIO__SAFE_RETAIN(_Right.get());

    ptr_ = (_Ty*)_Right.get();
  }

  _Myt& operator=(const _Myt& _Right) throw()
  { // assign compatible _Right (assume pointer)
    if (this == &_Right)
      return *this;

    YASIO__SAFE_RETAIN(_Right.get());

    reset(_Right.get());
    return (*this);
  }

  _Myt& operator=(_Myt&& _Right) throw()
  { // assign compatible _Right (assume pointer)

    YASIO__SAFE_RETAIN(_Right.get());

    reset(_Right.get());
    return (*this);
  }

  template <typename _Other> _Myt& operator=(const ref_ptr<_Other>& _Right) throw()
  { // assign compatible _Right (assume pointer)
    if (this == &_Right)
      return *this;

    YASIO__SAFE_RETAIN(_Right.get());

    reset((_Ty*)_Right.get());
    return (*this);
  }

  template <typename _Other> _Myt& operator=(ref_ptr<_Other>&& _Right) throw()
  { // assign compatible _Right (assume pointer)
    YASIO__SAFE_RETAIN(_Right.get());

    reset((_Ty*)_Right.get());
    return (*this);
  }

  _Myt& operator=(std::nullptr_t) throw()
  {
    reset();
    return (*this);
  }

  ~ref_ptr()
  { // release the object
    YASIO__SAFE_RELEASE(ptr_);
  }

  _Ty& operator*() const throw()
  {                 // return designated value
    return (*ptr_); // return (*get());
  }

  _Ty** operator&() throw() { return &(ptr_); }

  _Ty* operator->() const throw()
  {                // return pointer to class object
    return (ptr_); // return (get());
  }

  template <typename _Int> _Ty& operator[](_Int index) const throw() { return (ptr_[index]); }

  _Ty* get() const throw()
  { // return wrapped pointer
    return (ptr_);
  }

  _Ty*& get_ref() throw()
  { // return wrapped pointer
    return (ptr_);
  }

  operator _Ty*() const throw()
  { // convert to basic type
    return (ptr_);
  }

  /*
  ** if already have a valid pointer, will call release firstly
  */
  void reset(_Ty* _Ptr = 0)
  { // relese designated object and store new pointer
    if (ptr_ != _Ptr)
    {
      if (ptr_ != nullptr)
        YASIO__SAFE_RELEASE(ptr_);
      ptr_ = _Ptr;
    }
  }

private:
  _Ty* ptr_; // the wrapped object pointer
};

}; // namespace gc

}; // namespace yasio

#endif