godot-cpp/include/godot_cpp/classes/wrapped.hpp

/*************************************************************************/
/*  wrapped.hpp                                                          */
/*************************************************************************/
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/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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#ifndef GODOT_CPP_WRAPPED_HPP
#define GODOT_CPP_WRAPPED_HPP

#include <godot_cpp/core/memory.hpp>

#include <godot_cpp/godot.hpp>

namespace godot {

typedef void GodotObject;

// Base for all engine classes, to contain the pointer to the engine instance.
class Wrapped {
	friend class GDExtensionBinding;
	friend void postinitialize_handler(Wrapped *);

protected:
	virtual const char *_get_extension_class() const; // This is needed to retrieve the class name before the godot object has its _extension and _extension_instance members assigned.
	virtual const GDNativeInstanceBindingCallbacks *_get_bindings_callbacks() const = 0;

	void _postinitialize();

	Wrapped(const char *p_godot_class);
	Wrapped(GodotObject *p_godot_object);

public:
	static const char *get_class_static() {
		return "Wrapped";
	}

	// Must be public but you should not touch this.
	GodotObject *_owner = nullptr;
};

} // namespace godot

#define GDCLASS(m_class, m_inherits)                                                                               \
private:                                                                                                           \
	void operator=(const m_class &p_rval) {}                                                                       \
	friend class ::godot::ClassDB;                                                                                 \
                                                                                                                   \
protected:                                                                                                         \
	virtual const char *_get_extension_class() const override {                                                    \
		return get_class_static();                                                                                 \
	}                                                                                                              \
                                                                                                                   \
	virtual const GDNativeInstanceBindingCallbacks *_get_bindings_callbacks() const override {                     \
		return &___binding_callbacks;                                                                              \
	}                                                                                                              \
                                                                                                                   \
	static void (*_get_bind_methods())() {                                                                         \
		return &m_class::_bind_methods;                                                                            \
	}                                                                                                              \
                                                                                                                   \
	template <class T>                                                                                             \
	static void register_virtuals() {                                                                              \
		m_inherits::register_virtuals<T>();                                                                        \
	}                                                                                                              \
                                                                                                                   \
public:                                                                                                            \
	static void initialize_class() {                                                                               \
		static bool initialized = false;                                                                           \
		if (initialized) {                                                                                         \
			return;                                                                                                \
		}                                                                                                          \
		m_inherits::initialize_class();                                                                            \
		if (m_class::_get_bind_methods() != m_inherits::_get_bind_methods()) {                                     \
			_bind_methods();                                                                                       \
			m_inherits::register_virtuals<m_class>();                                                              \
		}                                                                                                          \
		initialized = true;                                                                                        \
	}                                                                                                              \
                                                                                                                   \
	static const char *get_class_static() {                                                                        \
		return #m_class;                                                                                           \
	}                                                                                                              \
                                                                                                                   \
	static const char *get_parent_class_static() {                                                                 \
		return m_inherits::get_class_static();                                                                     \
	}                                                                                                              \
                                                                                                                   \
	static GDNativeObjectPtr create(void *data) {                                                                  \
		m_class *new_object = memnew(m_class);                                                                     \
		return new_object->_owner;                                                                                 \
	}                                                                                                              \
                                                                                                                   \
	static void free(void *data, GDExtensionClassInstancePtr ptr) {                                                \
		if (ptr) {                                                                                                 \
			m_class *cls = reinterpret_cast<m_class *>(ptr);                                                       \
			cls->~m_class();                                                                                       \
			::godot::Memory::free_static(cls);                                                                     \
		}                                                                                                          \
	}                                                                                                              \
                                                                                                                   \
	static void *___binding_create_callback(void *p_token, void *p_instance) {                                     \
		return nullptr;                                                                                            \
	}                                                                                                              \
	static void ___binding_free_callback(void *p_token, void *p_instance, void *p_binding) {                       \
	}                                                                                                              \
	static GDNativeBool ___binding_reference_callback(void *p_token, void *p_instance, GDNativeBool p_reference) { \
		return true;                                                                                               \
	}                                                                                                              \
	static constexpr GDNativeInstanceBindingCallbacks ___binding_callbacks = {                                     \
		___binding_create_callback,                                                                                \
		___binding_free_callback,                                                                                  \
		___binding_reference_callback,                                                                             \
	};

// Don't use this for your classes, use GDCLASS() instead.
#define GDNATIVE_CLASS(m_class, m_inherits)                                                                        \
private:                                                                                                           \
	void operator=(const m_class &p_rval) {}                                                                       \
                                                                                                                   \
protected:                                                                                                         \
	virtual const GDNativeInstanceBindingCallbacks *_get_bindings_callbacks() const override {                     \
		return &___binding_callbacks;                                                                              \
	}                                                                                                              \
                                                                                                                   \
	m_class(const char *p_godot_class) : m_inherits(p_godot_class) {}                                              \
	m_class(GodotObject *p_godot_object) : m_inherits(p_godot_object) {}                                           \
                                                                                                                   \
	static void (*_get_bind_methods())() {                                                                         \
		return nullptr;                                                                                            \
	}                                                                                                              \
                                                                                                                   \
public:                                                                                                            \
	static void initialize_class() {}                                                                              \
                                                                                                                   \
	static const char *get_class_static() {                                                                        \
		return #m_class;                                                                                           \
	}                                                                                                              \
                                                                                                                   \
	static const char *get_parent_class_static() {                                                                 \
		return m_inherits::get_class_static();                                                                     \
	}                                                                                                              \
                                                                                                                   \
	static void *___binding_create_callback(void *p_token, void *p_instance) {                                     \
		/* Do not call memnew here, we don't want the postinitializer to be called */                              \
		return new ("") m_class((GodotObject *)p_instance);                                                        \
	}                                                                                                              \
	static void ___binding_free_callback(void *p_token, void *p_instance, void *p_binding) {                       \
		/* Explicitly call the deconstructor to ensure proper lifecycle for non-trivial members */                 \
		reinterpret_cast<m_class *>(p_binding)->~m_class();                                                        \
		Memory::free_static(reinterpret_cast<m_class *>(p_binding));                                               \
	}                                                                                                              \
	static GDNativeBool ___binding_reference_callback(void *p_token, void *p_instance, GDNativeBool p_reference) { \
		return true;                                                                                               \
	}                                                                                                              \
	static constexpr GDNativeInstanceBindingCallbacks ___binding_callbacks = {                                     \
		___binding_create_callback,                                                                                \
		___binding_free_callback,                                                                                  \
		___binding_reference_callback,                                                                             \
	};                                                                                                             \
	m_class() : m_class(#m_class) {}

#endif // ! GODOT_CPP_WRAPPED_HPP