Add methods to get argument count of methods

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

7 files changed, 54 insertions, 0 deletions

diff --git a/core/variant/callable.cpp b/core/variant/callable.cpp
index 6bad6f5a5b..a355cf513c 100644
--- a/core/variant/callable.cpp
+++ b/core/variant/callable.cpp
@@ -163,6 +163,20 @@ StringName Callable::get_method() const {
 	return method;
 }
 
+int Callable::get_argument_count(bool *r_is_valid) const {
+	if (is_custom()) {
+		bool valid = false;
+		return custom->get_argument_count(r_is_valid ? *r_is_valid : valid);
+	} else if (!is_null()) {
+		return get_object()->get_method_argument_count(method, r_is_valid);
+	} else {
+		if (r_is_valid) {
+			*r_is_valid = false;
+		}
+		return 0;
+	}
+}
+
 int Callable::get_bound_arguments_count() const {
 	if (!is_null() && is_custom()) {
 		return custom->get_bound_arguments_count();
@@ -417,6 +431,11 @@ const Callable *CallableCustom::get_base_comparator() const {
 	return nullptr;
 }
 
+int CallableCustom::get_argument_count(bool &r_is_valid) const {
+	r_is_valid = false;
+	return 0;
+}
+
 int CallableCustom::get_bound_arguments_count() const {
 	return 0;
 }
diff --git a/core/variant/callable.h b/core/variant/callable.h
index bba69d453e..63757d9d6e 100644
--- a/core/variant/callable.h
+++ b/core/variant/callable.h
@@ -109,6 +109,7 @@ public:
 	ObjectID get_object_id() const;
 	StringName get_method() const;
 	CallableCustom *get_custom() const;
+	int get_argument_count(bool *r_is_valid = nullptr) const;
 	int get_bound_arguments_count() const;
 	void get_bound_arguments_ref(Vector<Variant> &r_arguments, int &r_argcount) const; // Internal engine use, the exposed one is below.
 	Array get_bound_arguments() const;
@@ -155,6 +156,7 @@ public:
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const = 0;
 	virtual Error rpc(int p_peer_id, const Variant **p_arguments, int p_argcount, Callable::CallError &r_call_error) const;
 	virtual const Callable *get_base_comparator() const;
+	virtual int get_argument_count(bool &r_is_valid) const;
 	virtual int get_bound_arguments_count() const;
 	virtual void get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const;
 
diff --git a/core/variant/callable_bind.cpp b/core/variant/callable_bind.cpp
index 6d6c60cbd4..d82aa3583d 100644
--- a/core/variant/callable_bind.cpp
+++ b/core/variant/callable_bind.cpp
@@ -91,6 +91,14 @@ const Callable *CallableCustomBind::get_base_comparator() const {
 	return callable.get_base_comparator();
 }
 
+int CallableCustomBind::get_argument_count(bool &r_is_valid) const {
+	int ret = callable.get_argument_count(&r_is_valid);
+	if (r_is_valid) {
+		return ret - binds.size();
+	}
+	return 0;
+}
+
 int CallableCustomBind::get_bound_arguments_count() const {
 	return callable.get_bound_arguments_count() + binds.size();
 }
@@ -225,6 +233,14 @@ const Callable *CallableCustomUnbind::get_base_comparator() const {
 	return callable.get_base_comparator();
 }
 
+int CallableCustomUnbind::get_argument_count(bool &r_is_valid) const {
+	int ret = callable.get_argument_count(&r_is_valid);
+	if (r_is_valid) {
+		return ret + argcount;
+	}
+	return 0;
+}
+
 int CallableCustomUnbind::get_bound_arguments_count() const {
 	return callable.get_bound_arguments_count() - argcount;
 }
diff --git a/core/variant/callable_bind.h b/core/variant/callable_bind.h
index 5798797a3d..43cebb45f0 100644
--- a/core/variant/callable_bind.h
+++ b/core/variant/callable_bind.h
@@ -53,6 +53,7 @@ public:
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const override;
 	virtual Error rpc(int p_peer_id, const Variant **p_arguments, int p_argcount, Callable::CallError &r_call_error) const override;
 	virtual const Callable *get_base_comparator() const override;
+	virtual int get_argument_count(bool &r_is_valid) const override;
 	virtual int get_bound_arguments_count() const override;
 	virtual void get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const override;
 	Callable get_callable() { return callable; }
@@ -81,6 +82,7 @@ public:
 	virtual void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const override;
 	virtual Error rpc(int p_peer_id, const Variant **p_arguments, int p_argcount, Callable::CallError &r_call_error) const override;
 	virtual const Callable *get_base_comparator() const override;
+	virtual int get_argument_count(bool &r_is_valid) const override;
 	virtual int get_bound_arguments_count() const override;
 	virtual void get_bound_arguments(Vector<Variant> &r_arguments, int &r_argcount) const override;
 
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 060ea007ff..40c9a588d8 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -1053,6 +1053,10 @@ struct _VariantCall {
 		r_ret = callable->bindp(p_args, p_argcount);
 	}
 
+	static int func_Callable_get_argument_count(Callable *p_callable) {
+		return p_callable->get_argument_count();
+	}
+
 	static void func_Signal_emit(Variant *v, const Variant **p_args, int p_argcount, Variant &r_ret, Callable::CallError &r_error) {
 		Signal *signal = VariantGetInternalPtr<Signal>::get_ptr(v);
 		signal->emit(p_args, p_argcount);
@@ -2048,6 +2052,7 @@ static void _register_variant_builtin_methods() {
 	bind_method(Callable, get_object, sarray(), varray());
 	bind_method(Callable, get_object_id, sarray(), varray());
 	bind_method(Callable, get_method, sarray(), varray());
+	bind_function(Callable, get_argument_count, _VariantCall::func_Callable_get_argument_count, sarray(), varray());
 	bind_method(Callable, get_bound_arguments_count, sarray(), varray());
 	bind_method(Callable, get_bound_arguments, sarray(), varray());
 	bind_method(Callable, hash, sarray(), varray());
diff --git a/core/variant/variant_callable.cpp b/core/variant/variant_callable.cpp
index dc31b6d1ac..21f9a4f52b 100644
--- a/core/variant/variant_callable.cpp
+++ b/core/variant/variant_callable.cpp
@@ -68,6 +68,15 @@ ObjectID VariantCallable::get_object() const {
 	return ObjectID();
 }
 
+int VariantCallable::get_argument_count(bool &r_is_valid) const {
+	if (!Variant::has_builtin_method(variant.get_type(), method)) {
+		r_is_valid = false;
+		return 0;
+	}
+	r_is_valid = true;
+	return Variant::get_builtin_method_argument_count(variant.get_type(), method);
+}
+
 void VariantCallable::call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const {
 	Variant v = variant;
 	v.callp(method, p_arguments, p_argcount, r_return_value, r_call_error);
diff --git a/core/variant/variant_callable.h b/core/variant/variant_callable.h
index 3f2b058aaf..1811f3bb9a 100644
--- a/core/variant/variant_callable.h
+++ b/core/variant/variant_callable.h
@@ -50,6 +50,7 @@ public:
 	bool is_valid() const override;
 	StringName get_method() const override;
 	ObjectID get_object() const override;
+	int get_argument_count(bool &r_is_valid) const override;
 	void call(const Variant **p_arguments, int p_argcount, Variant &r_return_value, Callable::CallError &r_call_error) const override;
 
 	VariantCallable(const Variant &p_variant, const StringName &p_method);