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  1. #include <iostream>
  2.  
  3.     struct Cloneable
  4.     {
  5.     protected:
  6.         Cloneable(){}
  7.         Cloneable(const Cloneable &){}
  8.     public:
  9.         virtual ~Cloneable(){}
  10.  
  11.         Cloneable &operator=(const Cloneable &) = delete;
  12.  
  13.         virtual Cloneable *Clone() const = 0;
  14.         template<typename TextendsCloneable>
  15.         static void ReleaseClone(TextendsCloneable *&clone)
  16.         {
  17.             Cloneable *c = dynamic_cast<Cloneable *>(clone);
  18. //          if(!c) throw CloningException();
  19.             clone = /*nullptr*/0;
  20.             c->ReleaseClone(), c = /*nullptr*/0;
  21.         }
  22.     protected:
  23.         virtual void ReleaseClone() = 0;
  24.     public:
  25. //        struct CloningException : public virtual Exception
  26. //        {
  27. //            CloningException(){}
  28. //            CloningException(const char *msg) : Exception(msg) {}
  29. //            CloningException(const CloningException &) = delete;
  30. //            CloningException &operator=(const CloningException &) = delete;
  31. //            virtual ~CloningException(){}
  32. //        };
  33.  
  34.         template<typename InheritingClass>
  35.         struct Auto;
  36.     };
  37.  
  38.     template<typename InheritingClass>
  39.     struct Cloneable::Auto : public virtual Cloneable
  40.     {
  41.         virtual Cloneable *Clone() const
  42.         {
  43.             const InheritingClass *t = dynamic_cast<const InheritingClass *>(this);
  44.             if(!t)
  45.             {
  46. //                    throw CloningException();
  47.             }
  48.             return new InheritingClass(*t);
  49.         }
  50.     protected:
  51.         virtual void ReleaseClone()
  52.         {
  53.             if(!dynamic_cast<const InheritingClass *>(this))
  54.             {
  55. //                    throw CloningException();
  56.             }
  57.             delete this;
  58.         }
  59.     public:
  60.         virtual ~Auto(){}
  61.     };
  62.  
  63. struct MyAbstractClass : public virtual Cloneable
  64. {
  65.     MyAbstractClass(){}
  66. protected:
  67.     MyAbstractClass(const MyAbstractClass &){}
  68. public:
  69.     virtual ~MyAbstractClass(){}
  70.  
  71.     MyAbstractClass &operator=(const MyAbstractClass &) = delete;
  72.  
  73.     virtual void Tick() = 0;
  74. };
  75.  
  76. struct MyImplementationClass : public virtual MyAbstractClass, public virtual Cloneable::Auto<MyImplementationClass>
  77. {
  78.     MyImplementationClass(){}
  79. protected:
  80.     MyImplementationClass(const MyImplementationClass &){}
  81. public:
  82.     virtual ~MyImplementationClass(){}
  83.  
  84.     MyImplementationClass &operator=(const MyImplementationClass &) = delete;
  85.  
  86.     virtual void Tick();
  87.  
  88.     using Cloneable::Auto<MyImplementationClass>::Clone;
  89. protected:
  90.     using Cloneable::Auto<MyImplementationClass>::ReleaseClone;
  91. };
  92.  
  93. void MyImplementationClass::Tick()
  94. {
  95.     std::cout << "Tick" << std::endl;
  96. }
  97.  
  98. int main()
  99. {
  100.     MyImplementationClass a;
  101.     MyAbstractClass *b = dynamic_cast<MyAbstractClass *>(a.Clone());
  102.     b->Tick();
  103.     Cloneable::ReleaseClone(b);
  104. }
  105.  
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin
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Standard input is empty
compilation info 
prog.cpp: In member function 'Cloneable* Cloneable::Auto<InheritingClass>::Clone() const [with InheritingClass = MyImplementationClass, Cloneable = Cloneable]':
prog.cpp:101:66:   instantiated from here
prog.cpp:80:5: error: 'MyImplementationClass::MyImplementationClass(const MyImplementationClass&)' is protected
prog.cpp:48:42: error: within this context
stdout
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Standard output is empty
https://ideone.com/y5BGKH
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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