godot-cpp/include/godot_cpp/core/class_db.hpp

/*************************************************************************/
/*  class_db.hpp                                                         */
/*************************************************************************/
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#ifndef GODOT_CLASS_DB_HPP
#define GODOT_CLASS_DB_HPP

#include <godot/gdnative_interface.h>

#include <godot_cpp/core/defs.hpp>
#include <godot_cpp/core/error_macros.hpp>
#include <godot_cpp/core/method_bind.hpp>
#include <godot_cpp/core/object.hpp>

#include <list>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>

namespace godot {

#define DEFVAL(m_defval) (m_defval)

struct MethodDefinition {
	const char *name = nullptr;
	std::list<std::string> args;
	MethodDefinition() {}
	MethodDefinition(const char *p_name) :
			name(p_name) {}
};

MethodDefinition D_METHOD(const char *p_name);
MethodDefinition D_METHOD(const char *p_name, const char *p_arg1);
template <typename... Args>
MethodDefinition D_METHOD(const char *p_name, const char *p_arg1, Args... args) {
	MethodDefinition md = D_METHOD(p_name, args...);
	md.args.push_front(p_arg1);
	return md;
}

class ClassDB {
	static GDNativeInitializationLevel current_level;

	friend class godot::GDExtensionBinding;

public:
	struct PropertySetGet {
		int index;
		const char *setter;
		const char *getter;
		MethodBind *_setptr;
		MethodBind *_getptr;
		Variant::Type type;
	};

	struct ClassInfo {
		const char *name = nullptr;
		const char *parent_name = nullptr;
		GDNativeInitializationLevel level = GDNATIVE_INITIALIZATION_SCENE;
		std::unordered_map<std::string, MethodBind *> method_map;
		std::set<std::string> signal_names;
		std::unordered_map<std::string, GDNativeExtensionClassCallVirtual> virtual_methods;
		std::set<std::string> property_names;
		std::set<std::string> constant_names;
		// Pointer to the parent custom class, if any. Will be null if the parent class is a Godot class.
		ClassInfo *parent_ptr = nullptr;
	};

private:
	// This may only contain custom classes, not Godot classes
	static std::unordered_map<std::string, ClassInfo> classes;

	static MethodBind *bind_methodfi(uint32_t p_flags, MethodBind *p_bind, const MethodDefinition &method_name, const void **p_defs, int p_defcount);
	static void initialize_class(const ClassInfo &cl);
	static void bind_method_godot(const char *p_class_name, MethodBind *p_method);

	static _FORCE_INLINE_ char *_alloc_and_copy_cstr(const char *p_str) {
		size_t size = strlen(p_str) + 1;
		char *ret = reinterpret_cast<char *>(memalloc(size));
		memcpy(ret, p_str, size);
		return ret;
	}

public:
	template <class T>
	static void register_class();

	template <class N, class M, typename... VarArgs>
	static MethodBind *bind_method(N p_method_name, M p_method, VarArgs... p_args);

	template <class N, class M, typename... VarArgs>
	static MethodBind *bind_static_method(const char *p_class, N p_method_name, M p_method, VarArgs... p_args);

	template <class M>
	static MethodBind *bind_vararg_method(uint32_t p_flags, const char *p_name, M p_method, const MethodInfo &p_info = MethodInfo(), const std::vector<Variant> &p_default_args = std::vector<Variant>{}, bool p_return_nil_is_variant = true);

	static void add_property_group(const char *p_class, const char *p_name, const char *p_prefix);
	static void add_property_subgroup(const char *p_class, const char *p_name, const char *p_prefix);
	static void add_property(const char *p_class, const PropertyInfo &p_pinfo, const char *p_setter, const char *p_getter, int p_index = -1);
	static void add_signal(const char *p_class, const MethodInfo &p_signal);
	static void bind_integer_constant(const char *p_class_name, const char *p_enum_name, const char *p_constant_name, GDNativeInt p_constant_value, bool p_is_bitfield = false);
	static void bind_virtual_method(const char *p_class, const char *p_method, GDNativeExtensionClassCallVirtual p_call);

	static MethodBind *get_method(const char *p_class, const char *p_method);

	static GDNativeExtensionClassCallVirtual get_virtual_func(void *p_userdata, const char *p_name);

	static void initialize(GDNativeInitializationLevel p_level);
	static void deinitialize(GDNativeInitializationLevel p_level);
};

#define BIND_CONSTANT(m_constant) \
	godot::ClassDB::bind_integer_constant(get_class_static(), "", #m_constant, m_constant);

#define BIND_ENUM_CONSTANT(m_constant) \
	godot::ClassDB::bind_integer_constant(get_class_static(), godot::__constant_get_enum_name(m_constant, #m_constant), #m_constant, m_constant);

#define BIND_BITFIELD_FLAG(m_constant) \
	godot::ClassDB::bind_integer_constant(get_class_static(), godot::__constant_get_bitfield_name(m_constant, #m_constant), #m_constant, m_constant, true);

#define BIND_VIRTUAL_METHOD(m_class, m_method)                                                                                    \
	{                                                                                                                             \
		auto ___call##m_method = [](GDNativeObjectPtr p_instance, const GDNativeTypePtr *p_args, GDNativeTypePtr p_ret) -> void { \
			call_with_ptr_args(reinterpret_cast<m_class *>(p_instance), &m_class::m_method, p_args, p_ret);                       \
		};                                                                                                                        \
		godot::ClassDB::bind_virtual_method(m_class::get_class_static(), #m_method, ___call##m_method);                           \
	}

template <class T>
void ClassDB::register_class() {
	// Register this class within our plugin
	ClassInfo cl;
	cl.name = T::get_class_static();
	cl.parent_name = T::get_parent_class_static();
	cl.level = current_level;
	std::unordered_map<std::string, ClassInfo>::iterator parent_it = classes.find(cl.parent_name);
	if (parent_it != classes.end()) {
		// Assign parent if it is also a custom class
		cl.parent_ptr = &parent_it->second;
	}
	classes[cl.name] = cl;

	// Register this class with Godot
	GDNativeExtensionClassCreationInfo class_info = {
		T::set_bind, // GDNativeExtensionClassSet set_func;
		T::get_bind, // GDNativeExtensionClassGet get_func;
		T::get_property_list_bind, // GDNativeExtensionClassGetPropertyList get_property_list_func;
		T::free_property_list_bind, // GDNativeExtensionClassFreePropertyList free_property_list_func;
		T::property_can_revert_bind, // GDNativeExtensionClassPropertyCanRevert property_can_revert_func;
		T::property_get_revert_bind, // GDNativeExtensionClassPropertyGetRevert property_get_revert_func;
		T::notification_bind, // GDNativeExtensionClassNotification notification_func;
		T::to_string_bind, // GDNativeExtensionClassToString to_string_func;
		nullptr, // GDNativeExtensionClassReference reference_func;
		nullptr, // GDNativeExtensionClassUnreference unreference_func;
		T::create, // GDNativeExtensionClassCreateInstance create_instance_func; /* this one is mandatory */
		T::free, // GDNativeExtensionClassFreeInstance free_instance_func; /* this one is mandatory */
		&ClassDB::get_virtual_func, // GDNativeExtensionClassGetVirtual get_virtual_func;
		nullptr, // GDNativeExtensionClassGetRID get_rid;
		(void *)cl.name, // void *class_userdata;
	};

	internal::gdn_interface->classdb_register_extension_class(internal::library, cl.name, cl.parent_name, &class_info);

	// call bind_methods etc. to register all members of the class
	T::initialize_class();

	// now register our class within ClassDB within Godot
	initialize_class(classes[cl.name]);
}

template <class N, class M, typename... VarArgs>
MethodBind *ClassDB::bind_method(N p_method_name, M p_method, VarArgs... p_args) {
	Variant args[sizeof...(p_args) + 1] = { p_args..., Variant() }; // +1 makes sure zero sized arrays are also supported.
	const Variant *argptrs[sizeof...(p_args) + 1];
	for (uint32_t i = 0; i < sizeof...(p_args); i++) {
		argptrs[i] = &args[i];
	}
	MethodBind *bind = create_method_bind(p_method);
	return bind_methodfi(METHOD_FLAGS_DEFAULT, bind, p_method_name, sizeof...(p_args) == 0 ? nullptr : (const void **)argptrs, sizeof...(p_args));
}

template <class N, class M, typename... VarArgs>
MethodBind *ClassDB::bind_static_method(const char *p_class, N p_method_name, M p_method, VarArgs... p_args) {
	Variant args[sizeof...(p_args) + 1] = { p_args..., Variant() }; // +1 makes sure zero sized arrays are also supported.
	const Variant *argptrs[sizeof...(p_args) + 1];
	for (uint32_t i = 0; i < sizeof...(p_args); i++) {
		argptrs[i] = &args[i];
	}
	MethodBind *bind = create_static_method_bind(p_method);
	bind->set_instance_class(p_class);
	return bind_methodfi(0, bind, p_method_name, sizeof...(p_args) == 0 ? nullptr : (const void **)argptrs, sizeof...(p_args));
}

template <class M>
MethodBind *ClassDB::bind_vararg_method(uint32_t p_flags, const char *p_name, M p_method, const MethodInfo &p_info, const std::vector<Variant> &p_default_args, bool p_return_nil_is_variant) {
	MethodBind *bind = create_vararg_method_bind(p_method, p_info, p_return_nil_is_variant);
	ERR_FAIL_COND_V(!bind, nullptr);

	bind->set_name(p_name);
	bind->set_default_arguments(p_default_args);

	const char *instance_type = bind->get_instance_class();

	std::unordered_map<std::string, ClassInfo>::iterator type_it = classes.find(instance_type);
	if (type_it == classes.end()) {
		memdelete(bind);
		ERR_FAIL_V_MSG(nullptr, String("Class '{0}' doesn't exist.").format(instance_type));
	}

	ClassInfo &type = type_it->second;

	if (type.method_map.find(p_name) != type.method_map.end()) {
		memdelete(bind);
		ERR_FAIL_V_MSG(nullptr, String("Binding duplicate method: {0}::{1}.").format(Array::make(instance_type, p_method)));
	}

	// register our method bind within our plugin
	type.method_map[p_name] = bind;

	// and register with godot
	bind_method_godot(type.name, bind);

	return bind;
}

#define GDREGISTER_CLASS(m_class) ClassDB::register_class<m_class>();

} // namespace godot

#endif // GODOT_CLASS_DB_HPP