godot/core/method_bind.h

/*************************************************************************/
/*  method_bind.h                                                        */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/
#ifndef METHOD_BIND_H
#define METHOD_BIND_H

#include "list.h"
#include "variant.h"
#include "object.h"
#include <stdio.h>
#include "method_ptrcall.h"

/**
	@author Juan Linietsky <reduzio@gmail.com>
*/

#ifdef DEBUG_ENABLED
#define DEBUG_METHODS_ENABLED
#endif

enum MethodFlags {

	METHOD_FLAG_NORMAL=1,
	METHOD_FLAG_EDITOR=2,
	METHOD_FLAG_NOSCRIPT=4,
	METHOD_FLAG_CONST=8,
	METHOD_FLAG_REVERSE=16, // used for events
	METHOD_FLAG_VIRTUAL=32,
	METHOD_FLAG_FROM_SCRIPT=64,
	METHOD_FLAGS_DEFAULT=METHOD_FLAG_NORMAL,
};

template<class T>
struct VariantCaster {

	static _FORCE_INLINE_ T cast(const Variant& p_variant) {

		return p_variant;
	}
};

template<class T>
struct VariantCaster<T&> {

	static _FORCE_INLINE_ T cast(const Variant& p_variant) {

		return p_variant;
	}
};

template<class T>
struct VariantCaster<const T&> {

	static _FORCE_INLINE_ T cast(const Variant& p_variant) {

		return p_variant;
	}
};

#define _VC( m_idx )\
	(VariantCaster<P##m_idx>::cast( (m_idx-1)>=p_arg_count?get_default_argument(m_idx-1):*p_args[m_idx-1] ))

//SIMPLE_NUMERIC_TYPE is used to avoid a warning on Variant::get_type_for

#ifdef PTRCALL_ENABLED


#define VARIANT_ENUM_CAST( m_enum ) \
SIMPLE_NUMERIC_TYPE( m_enum );\
template<> \
struct VariantCaster<m_enum> {\
\
	static _FORCE_INLINE_ m_enum cast(const Variant& p_variant) {\
		return (m_enum)p_variant.operator int();\
	}\
};\
template<>\
struct PtrToArg< m_enum > {\
	_FORCE_INLINE_ static m_enum convert(const void* p_ptr) {\
		return m_enum(*reinterpret_cast<const int*>(p_ptr));\
	}\
	_FORCE_INLINE_ static void encode(m_enum p_val,const void* p_ptr) {\
		*(int*)p_ptr=p_val;\
	}\
};

#else


#define VARIANT_ENUM_CAST( m_enum ) \
SIMPLE_NUMERIC_TYPE( m_enum );\
template<> \
struct VariantCaster<m_enum> {\
\
	static _FORCE_INLINE_ m_enum cast(const Variant& p_variant) {\
		return (m_enum)p_variant.operator int();\
	}\
};


#endif


#define CHECK_ARG(m_arg)\
	if ((m_arg-1)<p_arg_count) {\
		Variant::Type argtype=get_argument_type(m_arg-1);\
		if (!Variant::can_convert_strict(p_args[m_arg-1]->get_type(),argtype)) {\
			r_error.error=Variant::CallError::CALL_ERROR_INVALID_ARGUMENT;\
			r_error.argument=m_arg-1;\
			r_error.expected=argtype;\
			return Variant();\
		}\
	}

#define CHECK_NOARG(m_arg)\
	{\
	 if (p_arg##m_arg.get_type()!=Variant::NIL) {\
		if (r_argerror) *r_argerror=(m_arg-1);\
		return CALL_ERROR_EXTRA_ARGUMENT;\
	 }\
	}

// some helpers

VARIANT_ENUM_CAST( Vector3::Axis );
VARIANT_ENUM_CAST( Image::Format );
VARIANT_ENUM_CAST( Error );
VARIANT_ENUM_CAST( wchar_t );
VARIANT_ENUM_CAST( Margin );
VARIANT_ENUM_CAST( Orientation );
VARIANT_ENUM_CAST( HAlign );

class MethodBind {


	int method_id;
	uint32_t hint_flags;
	StringName name;
	Vector<Variant> default_arguments;
	int default_argument_count;
	int argument_count;
#ifdef DEBUG_METHODS_ENABLED
	Vector<StringName> arg_names;
	Variant::Type *argument_types;
	StringName ret_type;
#endif
	bool _const;


protected:

	void _set_const(bool p_const);
#ifdef DEBUG_METHODS_ENABLED
	virtual Variant::Type _gen_argument_type(int p_arg) const=0;
	void _generate_argument_types(int p_count);
	void set_argument_types(Variant::Type *p_types) { argument_types=p_types; }
#endif
	void set_argument_count(int p_count) { argument_count=p_count; }
public:

	Vector<Variant> get_default_arguments() const { return default_arguments; }
	_FORCE_INLINE_ int get_default_argument_count() const { return default_argument_count; }

	_FORCE_INLINE_ Variant has_default_argument(int p_arg) const {

		int idx=argument_count-p_arg-1;

		if (idx<0 || idx>=default_arguments.size())
			return false;
		else
			return true;
	}

	_FORCE_INLINE_ Variant get_default_argument(int p_arg) const {

		int idx=argument_count-p_arg-1;

		if (idx<0 || idx>=default_arguments.size())
			return Variant();
		else
			return default_arguments[idx];
	}

#ifdef DEBUG_METHODS_ENABLED

	_FORCE_INLINE_ void set_return_type(const StringName& p_type) { ret_type=p_type; }
	_FORCE_INLINE_ StringName get_return_type() const { return ret_type; }

	_FORCE_INLINE_ Variant::Type get_argument_type(int p_argument) const {

		ERR_FAIL_COND_V(p_argument<-1 || p_argument>argument_count,Variant::NIL);
		return argument_types[p_argument+1];

	}

	PropertyInfo get_argument_info(int p_argument) const;

	void set_argument_names(const Vector<StringName>& p_names);
	Vector<StringName> get_argument_names() const;
#endif
	void set_hint_flags(uint32_t p_hint) { hint_flags=p_hint; }
	uint32_t get_hint_flags() const { return hint_flags|(is_const()?METHOD_FLAG_CONST:0); }
	virtual String get_instance_type() const=0;

	_FORCE_INLINE_ int get_argument_count() const { return argument_count; };

#if 0
	_FORCE_INLINE_ Variant call_safe(const Variant** p_args,int p_arg_count, Variant::CallError& r_error) {

		r_error.error=Variant::CallError::CALL_OK;
		check_call( p_args, &errorarg );
		if (!err)
			return call(p_object, VARIANT_ARG_PASS );

		VARIANT_ARGPTRS
		String errstr;
		String methodname = get_instance_type()+"::"+name;
		if (err==CALL_ERROR_ARGUMENT_TYPE) {
			errstr="Invalid Argument to call: '"+methodname+"'. Cannot convert argument "+itos(errorarg+1)+" from "+Variant::get_type_name(get_argument_type(errorarg))+" to "+Variant::get_type_name(argptr[errorarg]->get_type())+".";
		}
		if (err==CALL_ERROR_EXTRA_ARGUMENT) {
			errstr="Invalid call. Member function '"+methodname+"' takes "+itos(get_argument_count())+" argument, but argument "+itos(errorarg+1)+" was received.";
		}

		ERR_PRINT(errstr.ascii().get_data());
		return Variant();
	}
#endif
	virtual Variant call(Object* p_object,const Variant** p_args,int p_arg_count, Variant::CallError& r_error)=0;

#ifdef PTRCALL_ENABLED
	virtual void ptrcall(Object* p_object,const void** p_args,void* r_ret)=0;
#endif

	StringName get_name() const;
	void set_name(const StringName& p_name);
	_FORCE_INLINE_ int get_method_id() const { return method_id; }
	_FORCE_INLINE_ bool is_const() const { return _const; }


	void set_default_arguments(const Vector<Variant>& p_defargs);

	MethodBind();
	virtual ~MethodBind();
};


template<class T>
class MethodBindNative : public MethodBind {
public:
	typedef Variant (T::*NativeCall)(const Variant**,int ,Variant::CallError &);
protected:

	NativeCall call_method;
public:

	virtual Variant::Type _gen_argument_type(int p_arg) const {

		return Variant::NIL;
	}

	virtual Variant call(Object* p_object,const Variant** p_args,int p_arg_count, Variant::CallError& r_error) {

		T* instance=static_cast<T*>(p_object);
		return (instance->*call_method)(p_args,p_arg_count,r_error);
	}
	void set_method_info(const MethodInfo& p_info) {


		set_argument_count( p_info.arguments.size() );
#ifdef DEBUG_METHODS_ENABLED
		Variant::Type *at = memnew_arr( Variant::Type , p_info.arguments.size()+1 );
		at[0]=p_info.return_val.type;
		if (p_info.arguments.size()) {

			Vector<StringName> names;
			names.resize(p_info.arguments.size());
			for(int i=0;i<p_info.arguments.size();i++) {

				at[i+1]=p_info.arguments[i].type;
				names[i]=p_info.arguments[i].name;
			}

			set_argument_names(names);
		}
		set_argument_types(at);
#endif
	}

#ifdef PTRCALL_ENABLED
	virtual void ptrcall(Object* p_object,const void** p_args,void* r_ret) {} //todo
#endif


	void set_method(NativeCall p_method) { call_method=p_method; }
	virtual bool is_const() const { return false; }
	virtual String get_instance_type() const { return T::get_type_static(); }

	MethodBindNative() { call_method=NULL; }
};


template<class T   >
MethodBind* create_native_method_bind( Variant (T::*p_method)(const Variant**,int ,Variant::CallError &), const MethodInfo& p_info ) {

	MethodBindNative<T   > * a = memnew( (MethodBindNative<T   >) );
	a->set_method(p_method);
	a->set_method_info(p_info);
	return a;
}


/** This amazing hack is based on the FastDelegates theory */

// tale of an amazing hack.. //

// if you declare an nonexistent class..
class __UnexistingClass;


#include "method_bind.inc"

#endif