/*************************************************************************/
/*  gd_mono_method_thunk.h                                               */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#ifndef GD_MONO_METHOD_THUNK_H
#define GD_MONO_METHOD_THUNK_H

#include <type_traits>

#include "gd_mono_class.h"
#include "gd_mono_header.h"
#include "gd_mono_marshal.h"
#include "gd_mono_method.h"
#include "gd_mono_utils.h"

#if !defined(JAVASCRIPT_ENABLED) && !defined(IPHONE_ENABLED)
#define HAVE_METHOD_THUNKS
#endif

#ifdef HAVE_METHOD_THUNKS

template <class... ParamTypes>
struct GDMonoMethodThunk {

	typedef void(GD_MONO_STDCALL *M)(ParamTypes... p_args, MonoException **);

	M mono_method_thunk;

public:
	_FORCE_INLINE_ void invoke(ParamTypes... p_args, MonoException **r_exc) {
		GD_MONO_BEGIN_RUNTIME_INVOKE;
		mono_method_thunk(p_args..., r_exc);
		GD_MONO_END_RUNTIME_INVOKE;
	}

	_FORCE_INLINE_ bool is_null() {
		return mono_method_thunk == nullptr;
	}

	_FORCE_INLINE_ void nullify() {
		mono_method_thunk = nullptr;
	}

	_FORCE_INLINE_ void set_from_method(GDMonoMethod *p_mono_method) {
#ifdef DEBUG_ENABLED
		CRASH_COND(p_mono_method == nullptr);
		CRASH_COND(p_mono_method->get_return_type().type_encoding != MONO_TYPE_VOID);

		if (p_mono_method->is_static()) {
			CRASH_COND(p_mono_method->get_parameters_count() != sizeof...(ParamTypes));
		} else {
			CRASH_COND(p_mono_method->get_parameters_count() != (sizeof...(ParamTypes) - 1));
		}
#endif
		mono_method_thunk = (M)mono_method_get_unmanaged_thunk(p_mono_method->get_mono_ptr());
	}

	GDMonoMethodThunk() :
			mono_method_thunk(nullptr) {
	}

	explicit GDMonoMethodThunk(GDMonoMethod *p_mono_method) {
		set_from_method(p_mono_method);
	}
};

template <class R, class... ParamTypes>
struct GDMonoMethodThunkR {

	typedef R(GD_MONO_STDCALL *M)(ParamTypes... p_args, MonoException **);

	M mono_method_thunk;

public:
	_FORCE_INLINE_ R invoke(ParamTypes... p_args, MonoException **r_exc) {
		GD_MONO_BEGIN_RUNTIME_INVOKE;
		R r = mono_method_thunk(p_args..., r_exc);
		GD_MONO_END_RUNTIME_INVOKE;
		return r;
	}

	_FORCE_INLINE_ bool is_null() {
		return mono_method_thunk == nullptr;
	}

	_FORCE_INLINE_ void nullify() {
		mono_method_thunk = nullptr;
	}

	_FORCE_INLINE_ void set_from_method(GDMonoMethod *p_mono_method) {
#ifdef DEBUG_ENABLED
		CRASH_COND(p_mono_method == nullptr);
		CRASH_COND(p_mono_method->get_return_type().type_encoding == MONO_TYPE_VOID);

		if (p_mono_method->is_static()) {
			CRASH_COND(p_mono_method->get_parameters_count() != sizeof...(ParamTypes));
		} else {
			CRASH_COND(p_mono_method->get_parameters_count() != (sizeof...(ParamTypes) - 1));
		}
#endif
		mono_method_thunk = (M)mono_method_get_unmanaged_thunk(p_mono_method->get_mono_ptr());
	}

	GDMonoMethodThunkR() :
			mono_method_thunk(nullptr) {
	}

	explicit GDMonoMethodThunkR(GDMonoMethod *p_mono_method) {
#ifdef DEBUG_ENABLED
		CRASH_COND(p_mono_method == nullptr);
#endif
		mono_method_thunk = (M)mono_method_get_unmanaged_thunk(p_mono_method->get_mono_ptr());
	}
};

#else

template <unsigned int ThunkParamCount, class P1, class... ParamTypes>
struct VariadicInvokeMonoMethodImpl {
	static void invoke(GDMonoMethod *p_mono_method, P1 p_arg1, ParamTypes... p_args, MonoException **r_exc) {
		if (p_mono_method->is_static()) {
			void *args[ThunkParamCount] = { p_arg1, p_args... };
			p_mono_method->invoke_raw(nullptr, args, r_exc);
		} else {
			void *args[ThunkParamCount] = { p_args... };
			p_mono_method->invoke_raw((MonoObject *)p_arg1, args, r_exc);
		}
	}
};

template <unsigned int ThunkParamCount, class... ParamTypes>
struct VariadicInvokeMonoMethod {
	static void invoke(GDMonoMethod *p_mono_method, ParamTypes... p_args, MonoException **r_exc) {
		VariadicInvokeMonoMethodImpl<ThunkParamCount, ParamTypes...>::invoke(p_mono_method, p_args..., r_exc);
	}
};

template <>
struct VariadicInvokeMonoMethod<0> {
	static void invoke(GDMonoMethod *p_mono_method, MonoException **r_exc) {
#ifdef DEBUG_ENABLED
		CRASH_COND(!p_mono_method->is_static());
#endif
		p_mono_method->invoke_raw(nullptr, nullptr, r_exc);
	}
};

template <class P1>
struct VariadicInvokeMonoMethod<1, P1> {
	static void invoke(GDMonoMethod *p_mono_method, P1 p_arg1, MonoException **r_exc) {
		if (p_mono_method->is_static()) {
			void *args[1] = { p_arg1 };
			p_mono_method->invoke_raw(nullptr, args, r_exc);
		} else {
			p_mono_method->invoke_raw((MonoObject *)p_arg1, nullptr, r_exc);
		}
	}
};

template <class R>
R unbox_if_needed(MonoObject *p_val, const ManagedType &, typename std::enable_if<!std::is_pointer<R>::value>::type * = 0) {
	return GDMonoMarshal::unbox<R>(p_val);
}

template <class R>
R unbox_if_needed(MonoObject *p_val, const ManagedType &p_type, typename std::enable_if<std::is_pointer<R>::value>::type * = 0) {
	if (mono_class_is_valuetype(p_type.type_class->get_mono_ptr())) {
		return GDMonoMarshal::unbox<R>(p_val);
	} else {
		// If it's not a value type, we assume 'R' is a pointer to 'MonoObject' or a compatible type, like 'MonoException'.
		return (R)p_val;
	}
}

template <unsigned int ThunkParamCount, class R, class P1, class... ParamTypes>
struct VariadicInvokeMonoMethodRImpl {
	static R invoke(GDMonoMethod *p_mono_method, P1 p_arg1, ParamTypes... p_args, MonoException **r_exc) {
		if (p_mono_method->is_static()) {
			void *args[ThunkParamCount] = { p_arg1, p_args... };
			MonoObject *r = p_mono_method->invoke_raw(nullptr, args, r_exc);
			return unbox_if_needed<R>(r, p_mono_method->get_return_type());
		} else {
			void *args[ThunkParamCount] = { p_args... };
			MonoObject *r = p_mono_method->invoke_raw((MonoObject *)p_arg1, args, r_exc);
			return unbox_if_needed<R>(r, p_mono_method->get_return_type());
		}
	}
};

template <unsigned int ThunkParamCount, class R, class... ParamTypes>
struct VariadicInvokeMonoMethodR {
	static R invoke(GDMonoMethod *p_mono_method, ParamTypes... p_args, MonoException **r_exc) {
		return VariadicInvokeMonoMethodRImpl<ThunkParamCount, R, ParamTypes...>::invoke(p_mono_method, p_args..., r_exc);
	}
};

template <class R>
struct VariadicInvokeMonoMethodR<0, R> {
	static R invoke(GDMonoMethod *p_mono_method, MonoException **r_exc) {
#ifdef DEBUG_ENABLED
		CRASH_COND(!p_mono_method->is_static());
#endif
		MonoObject *r = p_mono_method->invoke_raw(nullptr, nullptr, r_exc);
		return unbox_if_needed<R>(r, p_mono_method->get_return_type());
	}
};

template <class R, class P1>
struct VariadicInvokeMonoMethodR<1, R, P1> {
	static R invoke(GDMonoMethod *p_mono_method, P1 p_arg1, MonoException **r_exc) {
		if (p_mono_method->is_static()) {
			void *args[1] = { p_arg1 };
			MonoObject *r = p_mono_method->invoke_raw(nullptr, args, r_exc);
			return unbox_if_needed<R>(r, p_mono_method->get_return_type());
		} else {
			MonoObject *r = p_mono_method->invoke_raw((MonoObject *)p_arg1, nullptr, r_exc);
			return unbox_if_needed<R>(r, p_mono_method->get_return_type());
		}
	}
};

template <class... ParamTypes>
struct GDMonoMethodThunk {

	GDMonoMethod *mono_method;

public:
	_FORCE_INLINE_ void invoke(ParamTypes... p_args, MonoException **r_exc) {
		VariadicInvokeMonoMethod<sizeof...(ParamTypes), ParamTypes...>::invoke(mono_method, p_args..., r_exc);
	}

	_FORCE_INLINE_ bool is_null() {
		return mono_method == nullptr;
	}

	_FORCE_INLINE_ void nullify() {
		mono_method = nullptr;
	}

	_FORCE_INLINE_ void set_from_method(GDMonoMethod *p_mono_method) {
#ifdef DEBUG_ENABLED
		CRASH_COND(p_mono_method == nullptr);
		CRASH_COND(p_mono_method->get_return_type().type_encoding != MONO_TYPE_VOID);

		if (p_mono_method->is_static()) {
			CRASH_COND(p_mono_method->get_parameters_count() != sizeof...(ParamTypes));
		} else {
			CRASH_COND(p_mono_method->get_parameters_count() != (sizeof...(ParamTypes) - 1));
		}
#endif
		mono_method = p_mono_method;
	}

	GDMonoMethodThunk() :
			mono_method(nullptr) {
	}

	explicit GDMonoMethodThunk(GDMonoMethod *p_mono_method) {
		set_from_method(p_mono_method);
	}
};

template <class R, class... ParamTypes>
struct GDMonoMethodThunkR {

	GDMonoMethod *mono_method;

public:
	_FORCE_INLINE_ R invoke(ParamTypes... p_args, MonoException **r_exc) {
		return VariadicInvokeMonoMethodR<sizeof...(ParamTypes), R, ParamTypes...>::invoke(mono_method, p_args..., r_exc);
	}

	_FORCE_INLINE_ bool is_null() {
		return mono_method == nullptr;
	}

	_FORCE_INLINE_ void nullify() {
		mono_method = nullptr;
	}

	_FORCE_INLINE_ void set_from_method(GDMonoMethod *p_mono_method) {
#ifdef DEBUG_ENABLED
		CRASH_COND(p_mono_method == nullptr);
		CRASH_COND(p_mono_method->get_return_type().type_encoding == MONO_TYPE_VOID);

		if (p_mono_method->is_static()) {
			CRASH_COND(p_mono_method->get_parameters_count() != sizeof...(ParamTypes));
		} else {
			CRASH_COND(p_mono_method->get_parameters_count() != (sizeof...(ParamTypes) - 1));
		}
#endif
		mono_method = p_mono_method;
	}

	GDMonoMethodThunkR() :
			mono_method(nullptr) {
	}

	explicit GDMonoMethodThunkR(GDMonoMethod *p_mono_method) {
		set_from_method(p_mono_method);
	}
};

#endif

#endif // GD_MONO_METHOD_THUNK_H