Add methods to get argument count of methods

Added to:
* `Callable`s
* `Object`s
* `ClassDB`
* `Script(Instance)`s

Author: AThousandShips

core/core_bind.cpp

@@ -1434,6 +1434,10 @@ bool ClassDB::class_has_method(const StringName &p_class, const StringName &p_me
 	return ::ClassDB::has_method(p_class, p_method, p_no_inheritance);
 }
 
+int ClassDB::class_get_method_argument_count(const StringName &p_class, const StringName &p_method, bool p_no_inheritance) const {
+	return ::ClassDB::get_method_argument_count(p_class, p_method, nullptr, p_no_inheritance);
+}
+
 TypedArray<Dictionary> ClassDB::class_get_method_list(const StringName &p_class, bool p_no_inheritance) const {
 	List<MethodInfo> methods;
 	::ClassDB::get_method_list(p_class, &methods, p_no_inheritance);
@@ -1562,6 +1566,8 @@ void ClassDB::_bind_methods() {
 
 	::ClassDB::bind_method(D_METHOD("class_has_method", "class", "method", "no_inheritance"), &ClassDB::class_has_method, DEFVAL(false));
 
+	::ClassDB::bind_method(D_METHOD("class_get_method_argument_count", "class", "method", "no_inheritance"), &ClassDB::class_get_method_argument_count, DEFVAL(false));
+
 	::ClassDB::bind_method(D_METHOD("class_get_method_list", "class", "no_inheritance"), &ClassDB::class_get_method_list, DEFVAL(false));
 
 	::ClassDB::bind_method(D_METHOD("class_get_integer_constant_list", "class", "no_inheritance"), &ClassDB::class_get_integer_constant_list, DEFVAL(false));

core/core_bind.h

@@ -447,6 +447,8 @@ class ClassDB : public Object {
 
 	bool class_has_method(const StringName &p_class, const StringName &p_method, bool p_no_inheritance = false) const;
 
+	int class_get_method_argument_count(const StringName &p_class, const StringName &p_method, bool p_no_inheritance = false) const;
+
 	TypedArray<Dictionary> class_get_method_list(const StringName &p_class, bool p_no_inheritance = false) const;
 
 	PackedStringArray class_get_integer_constant_list(const StringName &p_class, bool p_no_inheritance = false) const;

core/extension/gdextension_interface.cpp

@@ -59,6 +59,8 @@ class CallableCustomExtension : public CallableCustom {
 
 	GDExtensionCallableCustomToString to_string_func;
 
+	GDExtensionCallableCustomGetArgumentCount get_argument_count_func;
+
 	uint32_t _hash;
 
 	static bool default_compare_equal(const CallableCustom *p_a, const CallableCustom *p_b) {
@@ -143,6 +145,21 @@ class CallableCustomExtension : public CallableCustom {
 		return object;
 	}
 
+	int get_argument_count(bool &r_is_valid) const override {
+		if (get_argument_count_func != nullptr) {
+			GDExtensionBool is_valid = false;
+
+			GDExtensionInt ret = get_argument_count_func(userdata, &is_valid);
+
+			if (is_valid) {
+				r_is_valid = true;
+				return ret;
+			}
+		}
+		r_is_valid = false;
+		return 0;
+	}
+
 	void *get_userdata(void *p_token) const {
 		return (p_token == token) ? userdata : nullptr;
 	}
@@ -157,6 +174,7 @@ class CallableCustomExtension : public CallableCustom {
 		r_call_error.expected = error.expected;
 	}
 
+#ifndef DISABLE_DEPRECATED
 	CallableCustomExtension(GDExtensionCallableCustomInfo *p_info) {
 		userdata = p_info->callable_userdata;
 		token = p_info->token;
@@ -172,6 +190,35 @@ class CallableCustomExtension : public CallableCustom {
 
 		to_string_func = p_info->to_string_func;
 
+		get_argument_count_func = nullptr;
+
+		// Pre-calculate the hash.
+		if (p_info->hash_func != nullptr) {
+			_hash = p_info->hash_func(userdata);
+		} else {
+			_hash = hash_murmur3_one_64((uint64_t)call_func);
+			_hash = hash_murmur3_one_64((uint64_t)userdata, _hash);
+		}
+	}
+#endif
+
+	CallableCustomExtension(GDExtensionCallableCustomInfo2 *p_info) {
+		userdata = p_info->callable_userdata;
+		token = p_info->token;
+
+		object = p_info->object_id;
+
+		call_func = p_info->call_func;
+		is_valid_func = p_info->is_valid_func;
+		free_func = p_info->free_func;
+
+		equal_func = p_info->equal_func;
+		less_than_func = p_info->less_than_func;
+
+		to_string_func = p_info->to_string_func;
+
+		get_argument_count_func = p_info->get_argument_count_func;
+
 		// Pre-calculate the hash.
 		if (p_info->hash_func != nullptr) {
 			_hash = p_info->hash_func(userdata);
@@ -1378,9 +1425,15 @@ static GDExtensionScriptInstancePtr gdextension_object_get_script_instance(GDExt
 	return script_instance_extension->instance;
 }
 
+#ifndef DISABLE_DEPRECATED
 static void gdextension_callable_custom_create(GDExtensionUninitializedTypePtr r_callable, GDExtensionCallableCustomInfo *p_custom_callable_info) {
 	memnew_placement(r_callable, Callable(memnew(CallableCustomExtension(p_custom_callable_info))));
 }
+#endif
+
+static void gdextension_callable_custom_create2(GDExtensionUninitializedTypePtr r_callable, GDExtensionCallableCustomInfo2 *p_custom_callable_info) {
+	memnew_placement(r_callable, Callable(memnew(CallableCustomExtension(p_custom_callable_info))));
+}
 
 static void *gdextension_callable_custom_get_userdata(GDExtensionTypePtr p_callable, void *p_token) {
 	const Callable &callable = *reinterpret_cast<const Callable *>(p_callable);
@@ -1595,7 +1648,10 @@ void gdextension_setup_interface() {
 	REGISTER_INTERFACE_FUNC(placeholder_script_instance_create);
 	REGISTER_INTERFACE_FUNC(placeholder_script_instance_update);
 	REGISTER_INTERFACE_FUNC(object_get_script_instance);
+#ifndef DISABLE_DEPRECATED
 	REGISTER_INTERFACE_FUNC(callable_custom_create);
+#endif // DISABLE_DEPRECATED
+	REGISTER_INTERFACE_FUNC(callable_custom_create2);
 	REGISTER_INTERFACE_FUNC(callable_custom_get_userdata);
 	REGISTER_INTERFACE_FUNC(classdb_construct_object);
 	REGISTER_INTERFACE_FUNC(classdb_get_method_bind);

core/extension/gdextension_interface.h

@@ -442,6 +442,8 @@ typedef GDExtensionBool (*GDExtensionCallableCustomLessThan)(void *callable_user
 
 typedef void (*GDExtensionCallableCustomToString)(void *callable_userdata, GDExtensionBool *r_is_valid, GDExtensionStringPtr r_out);
 
+typedef GDExtensionInt (*GDExtensionCallableCustomGetArgumentCount)(void *callable_userdata, GDExtensionBool *r_is_valid);
+
 typedef struct {
 	/* Only `call_func` and `token` are strictly required, however, `object_id` should be passed if its not a static method.
 	 *
@@ -471,7 +473,40 @@ typedef struct {
 	GDExtensionCallableCustomLessThan less_than_func;
 
 	GDExtensionCallableCustomToString to_string_func;
-} GDExtensionCallableCustomInfo;
+} GDExtensionCallableCustomInfo; // Deprecated. Use GDExtensionCallableCustomInfo2 instead.
+
+typedef struct {
+	/* Only `call_func` and `token` are strictly required, however, `object_id` should be passed if its not a static method.
+	 *
+	 * `token` should point to an address that uniquely identifies the GDExtension (for example, the
+	 * `GDExtensionClassLibraryPtr` passed to the entry symbol function.
+	 *
+	 * `hash_func`, `equal_func`, and `less_than_func` are optional. If not provided both `call_func` and
+	 * `callable_userdata` together are used as the identity of the callable for hashing and comparison purposes.
+	 *
+	 * The hash returned by `hash_func` is cached, `hash_func` will not be called more than once per callable.
+	 *
+	 * `is_valid_func` is necessary if the validity of the callable can change before destruction.
+	 *
+	 * `free_func` is necessary if `callable_userdata` needs to be cleaned up when the callable is freed.
+	 */
+	void *callable_userdata;
+	void *token;
+
+	GDObjectInstanceID object_id;
+
+	GDExtensionCallableCustomCall call_func;
+	GDExtensionCallableCustomIsValid is_valid_func;
+	GDExtensionCallableCustomFree free_func;
+
+	GDExtensionCallableCustomHash hash_func;
+	GDExtensionCallableCustomEqual equal_func;
+	GDExtensionCallableCustomLessThan less_than_func;
+
+	GDExtensionCallableCustomToString to_string_func;
+
+	GDExtensionCallableCustomGetArgumentCount get_argument_count_func;
+} GDExtensionCallableCustomInfo2;
 
 /* SCRIPT INSTANCE EXTENSION */
 
@@ -2510,6 +2545,7 @@ typedef GDExtensionScriptInstanceDataPtr (*GDExtensionInterfaceObjectGetScriptIn
 /**
  * @name callable_custom_create
  * @since 4.2
+ * @deprecated in Godot 4.3. Use `callable_custom_create2` instead.
  *
  * Creates a custom Callable object from a function pointer.
  *
@@ -2520,6 +2556,19 @@ typedef GDExtensionScriptInstanceDataPtr (*GDExtensionInterfaceObjectGetScriptIn
  */
 typedef void (*GDExtensionInterfaceCallableCustomCreate)(GDExtensionUninitializedTypePtr r_callable, GDExtensionCallableCustomInfo *p_callable_custom_info);
 
+/**
+ * @name callable_custom_create2
+ * @since 4.3
+ *
+ * Creates a custom Callable object from a function pointer.
+ *
+ * Provided struct can be safely freed once the function returns.
+ *
+ * @param r_callable A pointer that will receive the new Callable.
+ * @param p_callable_custom_info The info required to construct a Callable.
+ */
+typedef void (*GDExtensionInterfaceCallableCustomCreate2)(GDExtensionUninitializedTypePtr r_callable, GDExtensionCallableCustomInfo2 *p_callable_custom_info);
+
 /**
  * @name callable_custom_get_userdata
  * @since 4.2

core/object/callable_method_pointer.h

@@ -93,6 +93,11 @@ class CallableCustomMethodPointer : public CallableCustomMethodPointerBase {
 		return data.instance->get_instance_id();
 	}
 
+	virtual int get_argument_count(bool &r_is_valid) const {
+		r_is_valid = true;
+		return sizeof...(P);
+	}
+
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const {
 		ERR_FAIL_NULL_MSG(ObjectDB::get_instance(ObjectID(data.object_id)), "Invalid Object id '" + uitos(data.object_id) + "', can't call method.");
 		call_with_variant_args(data.instance, data.method, p_arguments, p_argcount, r_call_error);
@@ -140,6 +145,11 @@ class CallableCustomMethodPointerRet : public CallableCustomMethodPointerBase {
 		return data.instance->get_instance_id();
 	}
 
+	virtual int get_argument_count(bool &r_is_valid) const {
+		r_is_valid = true;
+		return sizeof...(P);
+	}
+
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const {
 		ERR_FAIL_NULL_MSG(ObjectDB::get_instance(ObjectID(data.object_id)), "Invalid Object id '" + uitos(data.object_id) + "', can't call method.");
 		call_with_variant_args_ret(data.instance, data.method, p_arguments, p_argcount, r_return_value, r_call_error);
@@ -187,6 +197,11 @@ class CallableCustomMethodPointerRetC : public CallableCustomMethodPointerBase {
 		return data.instance->get_instance_id();
 	}
 
+	virtual int get_argument_count(bool &r_is_valid) const override {
+		r_is_valid = true;
+		return sizeof...(P);
+	}
+
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const override {
 		ERR_FAIL_NULL_MSG(ObjectDB::get_instance(ObjectID(data.object_id)), "Invalid Object id '" + uitos(data.object_id) + "', can't call method.");
 		call_with_variant_args_retc(data.instance, data.method, p_arguments, p_argcount, r_return_value, r_call_error);
@@ -238,6 +253,11 @@ class CallableCustomStaticMethodPointer : public CallableCustomMethodPointerBase
 		return ObjectID();
 	}
 
+	virtual int get_argument_count(bool &r_is_valid) const override {
+		r_is_valid = true;
+		return sizeof...(P);
+	}
+
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const override {
 		call_with_variant_args_static_ret(data.method, p_arguments, p_argcount, r_return_value, r_call_error);
 		r_return_value = Variant();
@@ -280,6 +300,11 @@ class CallableCustomStaticMethodPointerRet : public CallableCustomMethodPointerB
 		return ObjectID();
 	}
 
+	virtual int get_argument_count(bool &r_is_valid) const override {
+		r_is_valid = true;
+		return sizeof...(P);
+	}
+
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const override {
 		call_with_variant_args_static_ret(data.method, p_arguments, p_argcount, r_return_value, r_call_error);
 	}

core/object/class_db.cpp

@@ -1666,6 +1666,31 @@ bool ClassDB::has_method(const StringName &p_class, const StringName &p_method,
 	return false;
 }
 
+int ClassDB::get_method_argument_count(const StringName &p_class, const StringName &p_method, bool *r_is_valid, bool p_no_inheritance) {
+	OBJTYPE_RLOCK;
+
+	ClassInfo *type = classes.getptr(p_class);
+
+	while (type) {
+		MethodBind **method = type->method_map.getptr(p_method);
+		if (method && *method) {
+			if (r_is_valid) {
+				*r_is_valid = true;
+			}
+			return (*method)->get_argument_count();
+		}
+		if (p_no_inheritance) {
+			break;
+		}
+		type = type->inherits_ptr;
+	}
+
+	if (r_is_valid) {
+		*r_is_valid = false;
+	}
+	return 0;
+}
+
 void ClassDB::bind_method_custom(const StringName &p_class, MethodBind *p_method) {
 	_bind_method_custom(p_class, p_method, false);
 }

core/object/class_db.h

@@ -430,6 +430,7 @@ class ClassDB {
 	static void get_method_list(const StringName &p_class, List<MethodInfo> *p_methods, bool p_no_inheritance = false, bool p_exclude_from_properties = false);
 	static void get_method_list_with_compatibility(const StringName &p_class, List<Pair<MethodInfo, uint32_t>> *p_methods_with_hash, bool p_no_inheritance = false, bool p_exclude_from_properties = false);
 	static bool get_method_info(const StringName &p_class, const StringName &p_method, MethodInfo *r_info, bool p_no_inheritance = false, bool p_exclude_from_properties = false);
+	static int get_method_argument_count(const StringName &p_class, const StringName &p_method, bool *r_is_valid = nullptr, bool p_no_inheritance = false);
 	static MethodBind *get_method(const StringName &p_class, const StringName &p_name);
 	static MethodBind *get_method_with_compatibility(const StringName &p_class, const StringName &p_name, uint64_t p_hash, bool *r_method_exists = nullptr, bool *r_is_deprecated = nullptr);
 	static Vector<uint32_t> get_method_compatibility_hashes(const StringName &p_class, const StringName &p_name);

core/object/object.cpp

@@ -688,6 +688,59 @@ bool Object::has_method(const StringName &p_method) const {
 	return false;
 }
 
+int Object::_get_method_argument_count_bind(const StringName &p_method) const {
+	return get_method_argument_count(p_method);
+}
+
+int Object::get_method_argument_count(const StringName &p_method, bool *r_is_valid) const {
+	if (p_method == CoreStringNames::get_singleton()->_free) {
+		if (r_is_valid) {
+			*r_is_valid = true;
+		}
+		return 0;
+	}
+
+	if (script_instance) {
+		bool valid = false;
+		int ret = script_instance->get_method_argument_count(p_method, &valid);
+		if (valid) {
+			if (r_is_valid) {
+				*r_is_valid = true;
+			}
+			return ret;
+		}
+	}
+
+	{
+		bool valid = false;
+		int ret = ClassDB::get_method_argument_count(get_class_name(), p_method, &valid);
+		if (valid) {
+			if (r_is_valid) {
+				*r_is_valid = true;
+			}
+			return ret;
+		}
+	}
+
+	const Script *scr = Object::cast_to<Script>(this);
+	while (scr != nullptr) {
+		bool valid = false;
+		int ret = scr->get_script_method_argument_count(p_method, &valid);
+		if (valid) {
+			if (r_is_valid) {
+				*r_is_valid = true;
+			}
+			return ret;
+		}
+		scr = scr->get_base_script().ptr();
+	}
+
+	if (r_is_valid) {
+		*r_is_valid = false;
+	}
+	return 0;
+}
+
 Variant Object::getvar(const Variant &p_key, bool *r_valid) const {
 	if (r_valid) {
 		*r_valid = false;
@@ -1644,6 +1697,8 @@ void Object::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("has_method", "method"), &Object::has_method);
 
+	ClassDB::bind_method(D_METHOD("get_method_argument_count", "method"), &Object::_get_method_argument_count_bind);
+
 	ClassDB::bind_method(D_METHOD("has_signal", "signal"), &Object::has_signal);
 	ClassDB::bind_method(D_METHOD("get_signal_list"), &Object::_get_signal_list);
 	ClassDB::bind_method(D_METHOD("get_signal_connection_list", "signal"), &Object::_get_signal_connection_list);

core/object/object.h

@@ -654,6 +654,7 @@ class Object {
 	Variant _get_bind(const StringName &p_name) const;
 	void _set_indexed_bind(const NodePath &p_name, const Variant &p_value);
 	Variant _get_indexed_bind(const NodePath &p_name) const;
+	int _get_method_argument_count_bind(const StringName &p_name) const;
 
 	_FORCE_INLINE_ void _construct_object(bool p_reference);
 
@@ -865,6 +866,7 @@ class Object {
 	Variant property_get_revert(const StringName &p_name) const;
 
 	bool has_method(const StringName &p_method) const;
+	int get_method_argument_count(const StringName &p_method, bool *r_is_valid = nullptr) const;
 	void get_method_list(List<MethodInfo> *p_list) const;
 	Variant callv(const StringName &p_method, const Array &p_args);
 	virtual Variant callp(const StringName &p_method, const Variant **p_args, int p_argcount, Callable::CallError &r_error);