ogr_refcountedptr.h

/******************************************************************************
 *
 * Project:  OGR
 * Purpose:  Smart pointer around a class that has built-in reference counting.
 * Author:   Even Rouault <even dot rouault at spatialys.com>
 *
 ******************************************************************************
 * Copyright (c) 2026, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/
 
#ifndef OGR_REFCOUNTEDPTR_INCLUDED
#define OGR_REFCOUNTEDPTR_INCLUDED
 
#include <cstddef>
#include <utility>
 
template <class T> struct OGRRefCountedPtrBase
{
  public:
    inline ~OGRRefCountedPtrBase()
    {
        reset(nullptr);
    }
 
    inline OGRRefCountedPtrBase(const OGRRefCountedPtrBase &other)
        : OGRRefCountedPtrBase(other.m_poRawPtr, true)
    {
    }
 
    // cppcheck-suppress operatorEqVarError
    inline OGRRefCountedPtrBase &operator=(const OGRRefCountedPtrBase &other)
    {
        if (this != &other)
        {
            reset(other.m_poRawPtr);
        }
        return *this;
    }
 
    inline OGRRefCountedPtrBase(OGRRefCountedPtrBase &&other)
    {
        std::swap(m_poRawPtr, other.m_poRawPtr);
    }
 
    inline OGRRefCountedPtrBase &operator=(OGRRefCountedPtrBase &&other)
    {
        reset(nullptr);
        std::swap(m_poRawPtr, other.m_poRawPtr);
        return *this;
    }
 
    inline void reset(T *poRawPtr = nullptr, bool add_ref = true)
    {
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif
        if (m_poRawPtr)
            m_poRawPtr->Release();
        m_poRawPtr = poRawPtr;
        if (m_poRawPtr && add_ref)
            m_poRawPtr->Reference();
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
    }
 
    inline T *get() const
    {
        return m_poRawPtr;
    }
 
    inline T &operator*() const
    {
        return *m_poRawPtr;
    }
 
    inline T *operator->() const
    {
        return m_poRawPtr;
    }
 
    inline explicit operator bool() const
    {
        return m_poRawPtr != nullptr;
    }
 
  protected:
    inline explicit OGRRefCountedPtrBase(T *poRawPtr = nullptr,
                                         bool add_ref = true)
        : m_poRawPtr(poRawPtr)
    {
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif
        if (m_poRawPtr && add_ref)
            m_poRawPtr->Reference();
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
    }
 
  private:
    T *m_poRawPtr{};
};
 
template <class T> struct OGRRefCountedPtr : public OGRRefCountedPtrBase<T>
{
};
 
template <class T>
inline bool operator==(const OGRRefCountedPtr<T> &lhs, std::nullptr_t)
{
    return lhs.get() == nullptr;
}
 
template <class T>
inline bool operator==(std::nullptr_t, const OGRRefCountedPtr<T> &rhs)
{
    return rhs.get() == nullptr;
}
 
template <class T>
inline bool operator!=(const OGRRefCountedPtr<T> &lhs, std::nullptr_t)
{
    return lhs.get() != nullptr;
}
 
template <class T>
inline bool operator!=(std::nullptr_t, const OGRRefCountedPtr<T> &rhs)
{
    return rhs.get() != nullptr;
}
 
#endif /* OGR_REFCOUNTEDPTR_INCLUDED */