source/game/owned.h

   1 #ifndef MSP_GAME_OWNED_H_
   2 #define MSP_GAME_OWNED_H_
   3
   4 #include <stdexcept>
   5 #include "handle.h"
   6 #include "stage.h"
   7
   8 namespace Msp::Game {
   9
  10 class Component;
  11 class Entity;
  12
  13 template<typename T>
  14 class Owned: public Handle<T>
  15 {
  16 public:
  17         Owned() = default;
  18
  19         template<typename P, typename... Args>
  20         Owned(Handle<P>, Args &&...);
  21
  22         template<typename P, typename... Args>
  23         Owned(P &parent, Args &&... args): Owned(Handle<P>::from_object(&parent), std::forward<Args>(args)...) { }
  24
  25         Owned(Owned &&other): Handle<T>(other) { other.ptr = nullptr; }
  26         Owned &operator=(Owned &&other);
  27         ~Owned() { destroy(); }
  28
  29 private:
  30         template<typename O>
  31         static Stage &get_stage(O &);
  32
  33         void destroy();
  34 };
  35
  36
  37 template<typename T>
  38 template<typename P, typename... Args>
  39 Owned<T>::Owned(Handle<P> parent, Args &&... args)
  40 {
  41         if(!parent)
  42                 throw std::invalid_argument("Owned::Owned");
  43
  44         Pool<T> &pool = get_stage(*parent).get_pools().template get_pool<T>();
  45         this->ptr = pool.create(parent, std::forward<Args>(args)...);
  46         if constexpr(std::is_base_of_v<Component, T>)
  47                 parent->add_component(*this);
  48         else
  49                 parent->add_child(*this);
  50 }
  51
  52 template<typename T>
  53 Owned<T> &Owned<T>::operator=(Owned &&other)
  54 {
  55         destroy();
  56
  57         this->ptr = other.ptr;
  58         other.ptr = nullptr;
  59
  60         return *this;
  61 }
  62
  63 template<typename T>
  64 template<typename O>
  65 Stage &Owned<T>::get_stage(O &obj)
  66 {
  67         if constexpr(std::is_base_of_v<Component, O>)
  68                 return get_stage(*obj.get_entity());
  69         else
  70                 return obj.get_stage();
  71 }
  72
  73 template<typename T>
  74 void Owned<T>::destroy()
  75 {
  76         T *obj = this->get();
  77         if(!obj)
  78                 return;
  79
  80         Pool<T> &pool = get_stage(*obj).get_pools().template get_pool<T>();
  81
  82         if constexpr(std::is_base_of_v<Component, T>)
  83                 obj->get_entity()->remove_component(*this);
  84         else if(auto parent = obj->get_parent().get())
  85                 parent->remove_child(*this);
  86
  87         pool.destroy(this->ptr);
  88 }
  89
  90 } // namespace Msp::Game
  91
  92 #endif