text: /*************************************************************************/
  /*  reference.h                                                          */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
  /*                                                                       */
  /* Permission is hereby granted, free of charge, to any person obtaining */
  /* a copy of this software and associated documentation files (the       */
  /* "Software"), to deal in the Software without restriction, including   */
  /* without limitation the rights to use, copy, modify, merge, publish,   */
  /* distribute, sublicense, and/or sell copies of the Software, and to    */
  /* permit persons to whom the Software is furnished to do so, subject to */
  /* the following conditions:                                             */
  /*                                                                       */
  /* The above copyright notice and this permission notice shall be        */
  /* included in all copies or substantial portions of the Software.       */
  /*                                                                       */
  /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
  /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
  /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
  /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
  /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
  /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
  /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
  /*************************************************************************/
  
  #ifndef REFERENCE_H
  #define REFERENCE_H
  
  #include "core/class_db.h"
  #include "core/object.h"
  #include "core/ref_ptr.h"
  #include "core/safe_refcount.h"
  
  class Reference : public Object {
  	GDCLASS(Reference, Object);
  	friend class RefBase;
  	SafeRefCount refcount;
  	SafeRefCount refcount_init;
  
  protected:
  	static void _bind_methods();
  
  public:
  	_FORCE_INLINE_ bool is_referenced() const { return refcount_init.get() != 1; }
  	bool init_ref();
  	bool reference(); // returns false if refcount is at zero and didn't get increased
  	bool unreference();
  	int reference_get_count() const;
  
  	Reference();
  	~Reference();
  };
  
  template <class T>
  class Ref {
  	T *reference;
  
  	void ref(const Ref &p_from) {
  		if (p_from.reference == reference) {
  			return;
  		}
  
  		unref();
  
  		reference = p_from.reference;
  		if (reference) {
  			reference->reference();
  		}
  	}
  
  	void ref_pointer(T *p_ref) {
  		ERR_FAIL_COND(!p_ref);
  
  		if (p_ref->init_ref()) {
  			reference = p_ref;
  		}
  	}
  
  	//virtual Reference * get_reference() const { return reference; }
  public:
  	_FORCE_INLINE_ bool operator==(const T *p_ptr) const {
  		return reference == p_ptr;
  	}
  	_FORCE_INLINE_ bool operator!=(const T *p_ptr) const {
  		return reference != p_ptr;
  	}
  
  	_FORCE_INLINE_ bool operator<(const Ref<T> &p_r) const {
  		return reference < p_r.reference;
  	}
  	_FORCE_INLINE_ bool operator==(const Ref<T> &p_r) const {
  		return reference == p_r.reference;
  	}
  	_FORCE_INLINE_ bool operator!=(const Ref<T> &p_r) const {
  		return reference != p_r.reference;
  	}
  
  	_FORCE_INLINE_ T *operator->() {
  		return reference;
  	}
  
  	_FORCE_INLINE_ T *operator*() {
  		return reference;
  	}
  
  	_FORCE_INLINE_ const T *operator->() const {
  		return reference;
  	}
  
  	_FORCE_INLINE_ const T *ptr() const {
  		return reference;
  	}
  	_FORCE_INLINE_ T *ptr() {
  		return reference;
  	}
  
  	_FORCE_INLINE_ const T *operator*() const {
  		return reference;
  	}
  
  	RefPtr get_ref_ptr() const {
  		RefPtr refptr;
  		Ref<Reference> *irr = reinterpret_cast<Ref<Reference> *>(refptr.get_data());
  		*irr = *this;
  		return refptr;
  	};
  
  	operator Variant() const {
  		return Variant(get_ref_ptr());
  	}
  
  	void operator=(const Ref &p_from) {
  		ref(p_from);
  	}
  
  	template <class T_Other>
  	void operator=(const Ref<T_Other> &p_from) {
  		Reference *refb = const_cast<Reference *>(static_cast<const Reference *>(p_from.ptr()));
  		if (!refb) {
  			unref();
  			return;
  		}
  		Ref r;
  		r.reference = Object::cast_to<T>(refb);
  		ref(r);
  		r.reference = nullptr;
  	}
  
  	void operator=(const RefPtr &p_refptr) {
  		Ref<Reference> *irr = reinterpret_cast<Ref<Reference> *>(p_refptr.get_data());
  		Reference *refb = irr->ptr();
  		if (!refb) {
  			unref();
  			return;
  		}
  		Ref r;
  		r.reference = Object::cast_to<T>(refb);
  		ref(r);
  		r.reference = nullptr;
  	}
  
  	void operator=(const Variant &p_variant) {
  		RefPtr refptr = p_variant;
  		Ref<Reference> *irr = reinterpret_cast<Ref<Reference> *>(refptr.get_data());
  		Reference *refb = irr->ptr();
  		if (!refb) {
  			unref();
  			return;
  		}
  		Ref r;
  		r.reference = Object::cast_to<T>(refb);
  		ref(r);
  		r.reference = nullptr;
  	}
  
  	template <class T_Other>
  	void reference_ptr(T_Other *p_ptr) {
  		if (reference == p_ptr) {
  			return;
  		}
  		unref();
  
  		T *r = Object::cast_to<T>(p_ptr);
  		if (r) {
  			ref_pointer(r);
  		}
  	}
  
  	Ref(const Ref &p_from) {
  		reference = nullptr;
  		ref(p_from);
  	}
  
  	template <class T_Other>
  	Ref(const Ref<T_Other> &p_from) {
  		reference = nullptr;
  		Reference *refb = const_cast<Reference *>(static_cast<const Reference *>(p_from.ptr()));
  		if (!refb) {
  			unref();
  			return;
  		}
  		Ref r;
  		r.reference = Object::cast_to<T>(refb);
  		ref(r);
  		r.reference = nullptr;
  	}
  
  	Ref(T *p_reference) {
  		reference = nullptr;
  		if (p_reference) {
  			ref_pointer(p_reference);
  		}
  	}
  
  	Ref(const Variant &p_variant) {
  		RefPtr refptr = p_variant;
  		Ref<Reference> *irr = reinterpret_cast<Ref<Reference> *>(refptr.get_data());
  		reference = nullptr;
  		Reference *refb = irr->ptr();
  		if (!refb) {
  			unref();
  			return;
  		}
  		Ref r;
  		r.reference = Object::cast_to<T>(refb);
  		ref(r);
  		r.reference = nullptr;
  	}
  
  	Ref(const RefPtr &p_refptr) {
  		Ref<Reference> *irr = reinterpret_cast<Ref<Reference> *>(p_refptr.get_data());
  		reference = nullptr;
  		Reference *refb = irr->ptr();
  		if (!refb) {
  			unref();
  			return;
  		}
  		Ref r;
  		r.reference = Object::cast_to<T>(refb);
  		ref(r);
  		r.reference = nullptr;
  	}
  
  	inline bool is_valid() const { return reference != nullptr; }
  	inline bool is_null() const { return reference == nullptr; }
  
  	void unref() {
  		//TODO this should be moved to mutexes, since this engine does not really
  		// do a lot of referencing on references and stuff
  		// mutexes will avoid more crashes?
  
  		if (reference && reference->unreference()) {
  			memdelete(reference);
  		}
  		reference = nullptr;
  	}
  
  	void instance() {
  		ref(memnew(T));
  	}
  
  	Ref() {
  		reference = nullptr;
  	}
  
  	~Ref() {
  		unref();
  	}
  };
  
  typedef Ref<Reference> REF;
  
  class WeakRef : public Reference {
  	GDCLASS(WeakRef, Reference);
  
  	ObjectID ref;
  
  protected:
  	static void _bind_methods();
  
  public:
  	Variant get_ref() const;
  	void set_obj(Object *p_object);
  	void set_ref(const REF &p_ref);
  
  	WeakRef();
  };
  
  #ifdef PTRCALL_ENABLED
  
  template <class T>
  struct PtrToArg<Ref<T>> {
  	_FORCE_INLINE_ static Ref<T> convert(const void *p_ptr) {
  		return Ref<T>(const_cast<T *>(reinterpret_cast<const T *>(p_ptr)));
  	}
  
  	_FORCE_INLINE_ static void encode(Ref<T> p_val, const void *p_ptr) {
  		*(Ref<Reference> *)p_ptr = p_val;
  	}
  };
  
  template <class T>
  struct PtrToArg<const Ref<T> &> {
  	_FORCE_INLINE_ static Ref<T> convert(const void *p_ptr) {
  		return Ref<T>((T *)p_ptr);
  	}
  };
  
  //this is for RefPtr
  
  template <>
  struct PtrToArg<RefPtr> {
  	_FORCE_INLINE_ static RefPtr convert(const void *p_ptr) {
  		return Ref<Reference>(const_cast<Reference *>(reinterpret_cast<const Reference *>(p_ptr))).get_ref_ptr();
  	}
  
  	_FORCE_INLINE_ static void encode(RefPtr p_val, const void *p_ptr) {
  		Ref<Reference> r = p_val;
  		*(Ref<Reference> *)p_ptr = r;
  	}
  };
  
  template <>
  struct PtrToArg<const RefPtr &> {
  	_FORCE_INLINE_ static RefPtr convert(const void *p_ptr) {
  		return Ref<Reference>(const_cast<Reference *>(reinterpret_cast<const Reference *>(p_ptr))).get_ref_ptr();
  	}
  };
  
  #endif // PTRCALL_ENABLED
  
  #ifdef DEBUG_METHODS_ENABLED
  
  template <class T>
  struct GetTypeInfo<Ref<T>> {
  	static const Variant::Type VARIANT_TYPE = Variant::OBJECT;
  	static const GodotTypeInfo::Metadata METADATA = GodotTypeInfo::METADATA_NONE;
  
  	static inline PropertyInfo get_class_info() {
  		return PropertyInfo(Variant::OBJECT, String(), PROPERTY_HINT_RESOURCE_TYPE, T::get_class_static());
  	}
  };
  
  template <class T>
  struct GetTypeInfo<const Ref<T> &> {
  	static const Variant::Type VARIANT_TYPE = Variant::OBJECT;
  	static const GodotTypeInfo::Metadata METADATA = GodotTypeInfo::METADATA_NONE;
  
  	static inline PropertyInfo get_class_info() {
  		return PropertyInfo(Variant::OBJECT, String(), PROPERTY_HINT_RESOURCE_TYPE, T::get_class_static());
  	}
  };
  
  #endif // DEBUG_METHODS_ENABLED
  
  #endif // REFERENCE_H
  