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... Args>
  20         Owned(Handle<Entity>, Args &&...);
  21
  22         template<typename... Args>
  23         Owned(Entity &parent, Args &&... args): Owned(Handle<Entity>::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... Args>
  39 Owned<T>::Owned(Handle<Entity> parent, Args &&... args)
  40 {
  41         if(!parent)
  42                 throw std::invalid_argument("Owned::Owned");
  43
  44         using DependentEntity = std::conditional_t<sizeof(T), Entity, Entity>;
  45         Handle<DependentEntity> dparent = parent;
  46
  47         Pool<T> &pool = get_stage(*dparent).get_pools().template get_pool<T>();
  48         this->ptr = pool.create(parent, std::forward<Args>(args)...);
  49         if constexpr(std::is_base_of_v<Component, T>)
  50                 dparent->add_component(*this);
  51         else
  52                 dparent->add_child(*this);
  53 }
  54
  55 template<typename T>
  56 Owned<T> &Owned<T>::operator=(Owned &&other)
  57 {
  58         destroy();
  59
  60         this->ptr = other.ptr;
  61         other.ptr = nullptr;
  62
  63         return *this;
  64 }
  65
  66 template<typename T>
  67 template<typename O>
  68 Stage &Owned<T>::get_stage(O &obj)
  69 {
  70         if constexpr(std::is_base_of_v<Component, O>)
  71                 return get_stage(*obj.get_entity());
  72         else
  73                 return obj.get_stage();
  74 }
  75
  76 template<typename T>
  77 void Owned<T>::destroy()
  78 {
  79         T *obj = this->get();
  80         if(!obj)
  81                 return;
  82
  83         Pool<T> &pool = get_stage(*obj).get_pools().template get_pool<T>();
  84
  85         if constexpr(std::is_base_of_v<Component, T>)
  86                 obj->get_entity()->remove_component(*this);
  87         else if(auto parent = obj->get_parent().get())
  88                 parent->remove_child(*this);
  89
  90         pool.destroy(this->ptr);
  91 }
  92
  93 } // namespace Msp::Game
  94
  95 #endif