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  1. #include <iostream>
  2. #include <functional>
  3. #include <type_traits>
  4. #include <utility>
  5. #include <memory>
  6. #include <cstddef>
  7. #include <mutex>
  8. #include <map>
  9.  
  10. class ABase {};
  11.  
  12. class BBase {};
  13.  
  14. class APluginInstance : public ABase {
  15.  
  16. public:
  17.  
  18.     static std::shared_ptr<ABase> create(double a, double b)
  19.     {
  20.         return std::shared_ptr<ABase>(new APluginInstance(a,b));
  21.     }
  22.  
  23.     APluginInstance(double a, double b)
  24.     : ret(a + b)
  25.     {
  26.         std::cout << ret << std::endl;
  27.     }
  28.  
  29.     double ret;
  30. };
  31.  
  32.  
  33. class A2PluginInstance : public ABase {
  34.  
  35. public:
  36.  
  37.     static std::shared_ptr<ABase> create(double a, double b)
  38.     {
  39.         return std::shared_ptr<ABase>(new APluginInstance(a,b));
  40.     }
  41.  
  42.     A2PluginInstance(double a, double b)
  43.     : ret(a - b)
  44.     {
  45.         std::cout << ret << std::endl;
  46.     }
  47.  
  48.     double ret;
  49. };
  50.  
  51. class BPluginInstance : public BBase {
  52.  
  53. public:
  54.  
  55.     static std::shared_ptr<BBase> create(int a)
  56.     {
  57.         return std::shared_ptr<BBase>(new BPluginInstance(a));
  58.     }
  59.  
  60.     BPluginInstance(int a)
  61.     {
  62.         std::cout  << a << std::endl;
  63.     }
  64. };
  65.  
  66. class B2PluginInstance : public BBase {
  67.  
  68. public:
  69.  
  70.     static std::shared_ptr<BBase> create(int a)
  71.     {
  72.         return std::shared_ptr<BBase>(new B2PluginInstance(a));
  73.     }
  74.  
  75.     B2PluginInstance(int a)
  76.     {
  77.         std::cout  << -a << std::endl;
  78.     }
  79. };
  80.  
  81. template <typename PluginInstanceBaseType, typename ...Args>
  82. class Plugin
  83. {
  84. public:
  85.  
  86.     using PluginInstanceBase_t = PluginInstanceBaseType;
  87.  
  88.  
  89.     void setFunc(const std::function<PluginInstanceBaseType(Args...)>& func)
  90.     {
  91.         _createFunc = func;
  92.     }
  93.  
  94.     PluginInstanceBaseType create(const Args&... args)
  95.     {
  96.         return _createFunc(args...);
  97.     }
  98.  
  99.     std::function<PluginInstanceBaseType(Args...)> _createFunc;
  100.  
  101. };
  102.  
  103. using APlugin = Plugin<std::shared_ptr<ABase>, double, double>;
  104. using BPlugin = Plugin<std::shared_ptr<BBase>, int>;
  105.  
  106.  
  107.  
  108. template <typename PluginType>
  109. class Factory
  110. {
  111.  
  112. public:
  113.  
  114.     using PluginInstanceBase_t = typename PluginType::PluginInstanceBase_t;
  115.  
  116.     template <typename T, typename...Args>
  117.     void addPlugin(const std::string& name, T(*func)(Args...) )
  118.     {
  119.         addPlugin(name,std::function<T(Args...)>(func));
  120.     }
  121.  
  122.     template <typename T, typename...Args>
  123.     void addPlugin(const std::string& name, const std::function<T(Args...)>& f)
  124.     {
  125.         std::shared_ptr<PluginType> plugin(new PluginType());
  126.         plugin->setFunc(f);
  127.         _plugins[name] = plugin;
  128.     }
  129.  
  130.     template <typename... Args>
  131.     PluginInstanceBase_t create(const std::string& name, const Args&... args)
  132.     {
  133.         auto found = _plugins.find(name);
  134.         if (found == _plugins.end()) {
  135.             return PluginInstanceBase_t();
  136.         }
  137.         return found->second->create(args...);
  138.     }
  139.  
  140. private:
  141.  
  142.  
  143.     std::map<std::string, std::shared_ptr<PluginType> > _plugins;
  144. };
  145.  
  146.  
  147. using AFactory = Factory<APlugin>;
  148. using BFactory = Factory<BPlugin>;
  149.  
  150. int main()
  151. {
  152.  
  153.     {
  154.         // Works
  155.         APlugin tmpa;
  156.         tmpa.setFunc(APluginInstance::create);
  157.     }
  158.  
  159.     AFactory af;
  160.     BFactory bf;
  161.  
  162.     // Doesn't work
  163.     af.addPlugin("A1", APluginInstance::create);
  164.     af.addPlugin("A2", A2PluginInstance::create);
  165.     bf.addPlugin("B1", BPluginInstance::create);
  166.     bf.addPlugin("B2", B2PluginInstance::create);
  167.  
  168.  
  169.     std::shared_ptr<ABase> a = af.create("A1",2., 4.);
  170.     std::shared_ptr<ABase> a2 = af.create("A2",2., 4.);
  171.     std::shared_ptr<BBase> b = bf.create("B1", 1);
  172.     std::shared_ptr<BBase> b2 = bf.create("B2", 1);
  173.  
  174.     return 0;
  175. }
  176.  
Success #stdin #stdout 0s 4344KB
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https://ideone.com/QFqKXN
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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