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
   7 namespace Msp::Game {
   8
   9 class Component;
  10 class Entity;
  11 class Root;
  12 class Stage;
  13
  14 template<typename T>
  15 class Owned: public Handle<T>
  16 {
  17 public:
  18         Owned() = default;
  19
  20         template<typename... Args>
  21         Owned(Handle<Entity>, Args &&...);
  22
  23         template<typename... Args>
  24         Owned(Entity &parent, Args &&... args): Owned(Handle<Entity>::from_object(&parent), std::forward<Args>(args)...) { }
  25
  26         Owned(Owned &&other): Handle<T>(other) { other.ptr = nullptr; }
  27         Owned &operator=(Owned &&other);
  28         ~Owned() { destroy(); }
  29
  30 private:
  31         template<typename O>
  32         static Stage &get_stage(O &);
  33
  34         void destroy();
  35 };
  36
  37
  38 template<typename T>
  39 template<typename... Args>
  40 Owned<T>::Owned(Handle<Entity> parent, Args &&... args)
  41 {
  42         if(!parent)
  43                 throw std::invalid_argument("Owned::Owned");
  44
  45         using DependentEntity = std::conditional_t<sizeof(T), Entity, Entity>;
  46         Handle<DependentEntity> dparent = parent;
  47
  48         Pool<T> &pool = get_stage(*dparent).get_pools().template get_pool<T>();
  49         this->ptr = pool.create(parent, std::forward<Args>(args)...);
  50         if constexpr(std::is_base_of_v<Component, T>)
  51                 dparent->add_component(*this);
  52         else
  53                 dparent->add_child(*this);
  54 }
  55
  56 template<typename T>
  57 Owned<T> &Owned<T>::operator=(Owned &&other)
  58 {
  59         destroy();
  60
  61         this->ptr = other.ptr;
  62         other.ptr = nullptr;
  63
  64         return *this;
  65 }
  66
  67 template<typename T>
  68 template<typename O>
  69 Stage &Owned<T>::get_stage(O &obj)
  70 {
  71         using DependentRoot = std::conditional_t<sizeof(T), Root, Root>;
  72         if constexpr(std::is_base_of_v<Component, O>)
  73                 return get_stage(*obj.get_entity());
  74         else if constexpr(std::is_base_of_v<Entity, O>)
  75                 return dynamic_cast<DependentRoot &>(*obj.get_root()).get_stage();
  76         else
  77                 return obj;
  78 }
  79
  80 template<typename T>
  81 void Owned<T>::destroy()
  82 {
  83         T *obj = this->get();
  84         if(!obj)
  85                 return;
  86
  87         Pool<T> &pool = get_stage(*obj).get_pools().template get_pool<T>();
  88
  89         if constexpr(std::is_base_of_v<Component, T>)
  90                 obj->get_entity()->remove_component(*this);
  91         else if(auto parent = obj->get_parent().get())
  92                 parent->remove_child(*this);
  93
  94         pool.destroy(this->ptr);
  95 }
  96
  97 } // namespace Msp::Game
  98
  99 #endif