SharedPtr.hpp

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#pragma once
 
#include "AstGlobal.h"
 
AST_NAMESPACE_BEGIN
 
template<typename _Object>
class SharedPtr
{
public:
    SharedPtr()
        :m_object{ nullptr }
    {}
    SharedPtr(std::nullptr_t)
        :m_object{ nullptr }
    {
    }
    SharedPtr(_Object* obj)
        :m_object{ obj }
    {
        _incRef();
    }
    SharedPtr(const SharedPtr& ptr)
        :SharedPtr{ptr.get()}
    {
 
    }
    ~SharedPtr()
    {
        _decRef();
    }
    SharedPtr& operator=(const SharedPtr& ptr)
    {
        return this->operator=(ptr.get());
    }
 
    SharedPtr& operator=(_Object* obj)
    {
        if(obj != m_object){ 
            if(obj)
                obj->incRef();
            _decRef();
            m_object = obj;
        }
        return *this;
    }
    SharedPtr& operator=(std::nullptr_t)
    {
        reset();
        return *this;
    }
    // 这里还是设置为支持隐式转换，因为在很多情况下，我们需要将SharedPtr转换为_Object*
    // explicit 
    operator _Object*() const
    {
        return m_object;
    }
    explicit operator bool() const
    {
        return m_object != nullptr;
    }
    _Object* operator->() const
    {
        return m_object;
    }
    _Object* get() const
    {
        return m_object;
    }
    _Object* take()
    {
        _Object* obj = m_object;
        if(obj){
            obj->decRefNoDelete();
            m_object = nullptr;
        }
        return obj;
    }
    void reset()
    {
        _decRef();
        m_object = nullptr;
    }
protected:
    void _incRef()
    {
        if(m_object)
            m_object->incRef();
    }
    void _decRef()
    {
        if(m_object)
            m_object->decRef();
    }
protected:
    _Object* m_object{nullptr};
};
 
 
 
AST_NAMESPACE_END