source/game/owned.h

   1 #ifndef MSP_GAME_OWNED_H_
   2 #define MSP_GAME_OWNED_H_
   3
   4 #include <stdexcept>
   5 #include "accessguard.h"
   6 #include "events.h"
   7 #include "handle.h"
   8 #include "stage.h"
   9
  10 namespace Msp::Game {
  11
  12 class Component;
  13 class Entity;
  14
  15 template<typename T>
  16 class Owned: public Handle<T>
  17 {
  18 public:
  19         Owned() = default;
  20
  21         template<typename P, typename... Args>
  22         Owned(Handle<P>, Args &&...);
  23
  24         template<typename P, typename... Args>
  25         Owned(Owned<P> &p, Args &&... a): Owned(static_cast<Handle<P> &>(p), std::forward<Args>(a)...) { }
  26
  27         template<typename P, typename... Args>
  28                 requires(!std::is_const_v<P>)
  29         Owned(P &parent, Args &&... args): Owned(Handle<P>::from_object(&parent), std::forward<Args>(args)...) { }
  30
  31         Owned(Owned &&other): Handle<T>(other) { other.ptr = nullptr; }
  32         Owned &operator=(Owned &&other);
  33         ~Owned() { destroy(); }
  34
  35 private:
  36         template<typename O>
  37         static Stage &get_stage(O &);
  38
  39         void destroy();
  40 };
  41
  42
  43 template<typename T>
  44 template<typename P, typename... Args>
  45 Owned<T>::Owned(Handle<P> parent, Args &&... args)
  46 {
  47 #ifdef DEBUG
  48         AccessGuard::get_instance().check<AccessGuard::Create>();
  49 #endif
  50
  51         if(!parent)
  52                 throw std::invalid_argument("Owned::Owned");
  53
  54         Stage &stage = get_stage(*parent);
  55         Pool<T> &pool = stage.get_pools().get_pool<T>();
  56         this->ptr = pool.create(parent, std::forward<Args>(args)...);
  57         if constexpr(std::is_base_of_v<Component, T>)
  58         {
  59                 parent->add_component(*this);
  60                 stage.get_event_source().emit<Events::ComponentCreated>(*this);
  61         }
  62         else
  63         {
  64                 parent->add_child(*this);
  65                 stage.get_event_source().emit<Events::EntityCreated>(*this);
  66         }
  67 }
  68
  69 template<typename T>
  70 Owned<T> &Owned<T>::operator=(Owned &&other)
  71 {
  72         destroy();
  73
  74         this->ptr = other.ptr;
  75         other.ptr = nullptr;
  76
  77         return *this;
  78 }
  79
  80 template<typename T>
  81 template<typename O>
  82 Stage &Owned<T>::get_stage(O &obj)
  83 {
  84         if constexpr(std::is_base_of_v<Component, O>)
  85                 return get_stage(*obj.get_entity());
  86         else
  87                 return obj.get_stage();
  88 }
  89
  90 template<typename T>
  91 void Owned<T>::destroy()
  92 {
  93         T *obj = this->get();
  94         if(!obj)
  95                 return;
  96
  97 #ifdef DEBUG
  98         AccessGuard::get_instance().check<AccessGuard::Destroy>();
  99 #endif
 100
 101         Stage &stage = get_stage(*obj);
 102
 103         if constexpr(std::is_base_of_v<Component, T>)
 104         {
 105                 stage.get_event_source().emit<Events::ComponentDestroyed>(*this);
 106                 obj->get_entity()->remove_component(*this);
 107         }
 108         else if(auto parent = obj->get_parent().get())
 109         {
 110                 stage.get_event_source().emit<Events::EntityDestroyed>(*this);
 111                 parent->remove_child(*this);
 112         }
 113
 114         Pool<T> &pool = stage.get_pools().get_pool<T>();
 115         pool.destroy(this->ptr);
 116 }
 117
 118 } // namespace Msp::Game
 119
 120 #endif