将深层复制ctor添加到std :: unique_ptr< my_type> [英] Add a deep copy ctor to std::unique_ptr<my_type>

问题描述

我想在 std :: vector 中存储一些 std :: unique_ptr< my_type> 。由于 my_type 提供了一个 clone（）方法，可以非常简单地创建 my_type * 。关键是如何扩展 std :: unique_ptr 保留所有的功能，同时添加copy ctor和赋值运算符。遗产？ Templace专业化？

I would like to store some std::unique_ptr<my_type> into a std::vector. Since my_type provides a clone() method it's quite straightforward to make deep copies of my_type *. The point is how to extend std::unique_ptr preserving all its functionalities while adding the copy ctor and the assignment operator. Inheritance? Templace specialization? Could you please provide a code snippet?

推荐答案

这看起来像一条路：

struct my_type_ptr: public std::unique_ptr<my_type,std::default_delete<my_type>>{
  using unique_ptr::unique_ptr; //inheriting constructors

  //adding copy ctor and assigment operator      
  my_type_ptr(const my_type_ptr & o):
    unique_ptr<my_type,std::default_delete<my_type>>()
    { reset( o ? o->clone() : nullptr); } 
  my_type_ptr& operator=(const my_type_ptr & o)
    { reset( o ? o->clone() : nullptr); return *this; }
};

它编译时没有gcc和clang的任何警告，valgrind不报告任何内存泄漏，周围有副本和向量。

It compiles without any warning from gcc and clang, and valgrind doesn't report any memory leak while playing around with copies and vectors.

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