moLuna.h

Go to the documentation of this file.

/*******************************************************************************

                                  moLuna.h

  ****************************************************************************
  *                                                                          *
  *   This source is free software; you can redistribute it and/or modify    *
  *   it under the terms of the GNU General Public License as published by   *
  *   the Free Software Foundation; either version 2 of the License, or      *
  *  (at your option) any later version.                                     *
  *                                                                          *
  *   This code is distributed in the hope that it will be useful, but       *
  *   WITHOUT ANY WARRANTY; without even the implied warranty of             *
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU      *
  *   General Public License for more details.                               *
  *                                                                          *
  *   A copy of the GNU General Public License is available on the World     *
  *   Wide Web at <http://www.gnu.org/copyleft/gpl.html>. You can also       *
  *   obtain it by writing to the Free Software Foundation,                  *
  *   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.         *
  *                                                                          *
  ****************************************************************************

  Copyright(C) 2006 Fabricio Costa

  Authors:
  Fabricio Costa
  Andrés Colubri

  Description:
  Implementa un método para agregar clases de moldeo a la máquina virtual de LUA,
  de manera tal que puedan ser creadas y accedidas desde los scripts. Para mas
  información al respecto:
  http://lua-users.org/wiki/SimpleCppBinding
  http://lua-users.org/wiki/SimplerCppBinding
  http://lua-users.org/wiki/CppBindingWithLunar
  Cada link describe un método diferente, el que se utiliza aquí es el segundo.

  Fabricio Costa > versión 2011 implementada en base a:
  http://lua-users.org/wiki/LunaFourCode
  http://lua-users.org/wiki/LunaFour

*******************************************************************************/

#ifndef __MO_LUNA_H__
#define __MO_LUNA_H__

#include "moTypes.h"

#undef check

#include <string>
#include <vector>
#include <list>

extern "C"
{
   #include "lua.h"
   #include "lauxlib.h"
   #include "lualib.h"
}

template <typename T> class moLuna {
    typedef struct { T *pT; } userdataType;
public:

  enum { NUMBER, STRING };

  struct PropertyType {
      const char     *name;
      int             (T::*getter) (lua_State *);
      int             (T::*setter) (lua_State *);
  };

  struct FunctionType {
    const char     *name;
    int             (T::*function) (lua_State *);
  };


    //typedef int (T::*mfp)(lua_State *L);
    //typedef struct { const char *name; mfp mfunc; } RegType;



  /*
    static T       *check(lua_State * L, int narg) {
    // Check to see whether we are a table
        if (lua_istable(L,narg+1))
        {
            lua_gettablevalue(L,narg+1,0);
            userdataType   *ud =
                    static_cast <userdataType * >(luaL_checkudata(L, -1, T::className));
            if (!ud)
                luaL_typerror(L, narg+1, T::className);
            lua_pop(L,1);
            return ud->pT;      // pointer to T object
        }
        else
        {
            luaL_typerror(L, narg+1, T::className);
        }
    }
*/

  /*
    static T       *lightcheck(lua_State * L, int narg) {
    // Check to see whether we are a table
        if (lua_istable(L,narg+1))
        {
            lua_gettablevalue(L,narg+1,0); ///doesn't work
            userdataType   *ud =
                    static_cast <userdataType * >(luaL_testudata(L, -1, T::className));
            if (!ud)
                return NULL; // lightcheck returns NULL if not found.
            lua_pop(L,1);
            return ud->pT;      // pointer to T object
        }
        else
        {
            return NULL;
        }
    }
*/

     /*
    static void Register(lua_State *L) {
        lua_newtable(L);
        int methods = lua_gettop(L);

        luaL_newmetatable(L, T::className);
        int metatable = lua_gettop(L);

        // store method table in globals so that
        // scripts can add functions written in Lua.
        lua_pushstring(L, T::className);
        lua_pushvalue(L, methods);
        lua_settable(L, LUA_GLOBALSINDEX);

        lua_pushliteral(L, "__metatable");
        lua_pushvalue(L, methods);
        lua_settable(L, metatable);  // hide metatable from Lua getmetatable()

        lua_pushliteral(L, "__index");
        lua_pushvalue(L, methods);
        lua_settable(L, metatable);

        lua_pushliteral(L, "__tostring");
        lua_pushcfunction(L, tostring_T);
        lua_settable(L, metatable);

        lua_pushliteral(L, "__gc");
        lua_pushcfunction(L, gc_T);
        lua_settable(L, metatable);

        lua_newtable(L);                // mt for method table
        int mt = lua_gettop(L);
        lua_pushliteral(L, "__call");
        lua_pushcfunction(L, new_T);
        lua_pushliteral(L, "new");
        lua_pushvalue(L, -2);           // dup new_T function
        lua_settable(L, methods);       // add new_T to method table
        lua_settable(L, mt);            // mt.__call = new_T
        lua_setmetatable(L, methods);

        // fill method table with methods from class T
        for (RegType *l = T::methods; l->name; l++) {
            // edited by Snaily: shouldn't it be const RegType *l ... ?
            lua_pushstring(L, l->name);
            lua_pushlightuserdata(L, (void*)l);
            lua_pushcclosure(L, thunk, 1);
            lua_settable(L, methods);
        }

        lua_pop(L, 2);  // drop metatable and method table
    }
*/


    // REGISTER CLASS AS A GLOBAL TABLE
    static void     Register(lua_State * L, const char *namespac = "") {

      if (strcmp(namespac, "") != 0) {
          lua_getglobal(L, namespac);
          lua_pushcfunction(L, &moLuna < T >::constructor);
          lua_setfield(L, -2, T::className);
          lua_pop(L, 1);
      } else {
          lua_pushcfunction(L, &moLuna < T >::constructor);
          lua_setglobal(L, T::className);
      }

      luaL_newmetatable(L, T::className);
      int             metatable = lua_gettop(L);

      lua_pushstring(L, "__gc");
      lua_pushcfunction(L, &moLuna < T >::gc_obj);
      lua_settable(L, metatable);

      lua_pushstring(L, "__index");
      lua_pushcfunction(L, &moLuna < T >::property_getter);
      lua_settable(L, metatable);

      lua_pushstring(L, "__setindex");
      lua_pushcfunction(L, &moLuna < T >::property_setter);
      lua_settable(L, metatable);

    }


    static int      constructor(lua_State * L) {

        lua_newtable(L);

        int             newtable = lua_gettop(L);

        lua_pushnumber(L, 0);

        T             **a = (T **) lua_newuserdata(L, sizeof(T *));
        //correction
        //T              *obj = new T(L, true);
        T              *obj = new T(L);
        *a = obj;

        int             userdata = lua_gettop(L);

        luaL_getmetatable(L, T::className);

        lua_setmetatable(L, userdata);

        lua_settable(L, newtable);

        luaL_getmetatable(L, T::className);
        lua_setmetatable(L, newtable);

        luaL_getmetatable(L, T::className);

        for (int i = 0; T::Properties[i].name; i++) {
            lua_pushstring(L, T::Properties[i].name);
            lua_pushnumber(L, i);
            lua_settable(L, -3);
        }

        lua_pop(L, 1);

        for (int i = 0; T::Functions[i].name; i++) {
            lua_pushstring(L, T::Functions[i].name);
            lua_pushnumber(L, i);
            lua_pushcclosure(L, &moLuna < T >::function_dispatch, 1);
            lua_settable(L, newtable);
        }

        return 1;
    }

    static T       *createNew(lua_State * L) {

      lua_newtable(L);

      int             newtable = lua_gettop(L);

      lua_pushnumber(L, 0);

      T             **a = (T **) lua_newuserdata(L, sizeof(T *));
      T              *obj = new T(L, false);
      obj->isExisting = false;
      *a = obj;

      int             userdata = lua_gettop(L);

      luaL_getmetatable(L, T::className);

      lua_setmetatable(L, userdata);

      lua_settable(L, newtable);

      luaL_getmetatable(L, T::className);
      lua_setmetatable(L, newtable);

      luaL_getmetatable(L, T::className);

      for (int i = 0; T::Properties[i].name; i++) {
          // ADD NAME KEY
          lua_pushstring(L, T::Properties[i].name);
          lua_pushnumber(L, i);
          lua_settable(L, -3);
      }

      lua_pop(L, 1);

      for (int i = 0; T::Functions[i].name; i++) {
          lua_pushstring(L, T::Functions[i].name);
          lua_pushnumber(L, i);
          lua_pushcclosure(L, &moLuna < T >::function_dispatch, 1);
          lua_settable(L, newtable);
      }

      return obj;
    }

    static T       *createFromExisting(lua_State * L, T * existingobj) {

      lua_newtable(L);

      int newtable = lua_gettop(L);

      lua_pushnumber(L, 0);

      T **a = (T **) lua_newuserdata(L, sizeof(T *));
      T *obj = existingobj;
      obj->isExisting = true;
      *a = obj;

      int userdata = lua_gettop(L);


      luaL_getmetatable(L, T::className);

      lua_setmetatable(L, userdata);

      lua_settable(L, newtable);

      luaL_getmetatable(L, T::className);
      lua_setmetatable(L, newtable);

      luaL_getmetatable(L, T::className);

      for (int i = 0; T::Properties[i].name; i++) {
          lua_pushstring(L, T::Properties[i].name);
          lua_pushnumber(L, i);
          lua_settable(L, -3);
      }

      lua_pop(L, 1);

      for (int i = 0; T::Functions[i].name; i++) {
          lua_pushstring(L, T::Functions[i].name);
          lua_pushnumber(L, i);
          lua_pushcclosure(L, &moLuna < T >::function_dispatch, 1);
          lua_settable(L, newtable);
      }

      return obj;
    }

    static int      property_getter(lua_State * L) {

      lua_pushvalue(L, 2);

      lua_getmetatable(L, 1);

      lua_pushvalue(L, 2);
      lua_rawget(L, -2);

      if (lua_isnumber(L, -1)) {

          int             _index = lua_tonumber(L, -1);

          lua_pushnumber(L, 0);
          lua_rawget(L, 1);

          T             **obj =
        static_cast < T ** >(lua_touserdata(L, -1));

          lua_pushvalue(L, 3);

          //const PropertyType *_properties = (*obj)->T::Properties;

        int result = ((*obj)->*(T::Properties[_index].getter)) (L);

          return result;

      }
      // PUSH NIL
      lua_pushnil(L);

      return 1;

    }

    static int      property_setter(lua_State * L) {

      lua_getmetatable(L, 1);

      lua_pushvalue(L, 2);
      lua_rawget(L, -2);

      if (lua_isnil(L, -1)) {

          lua_pop(L, 2);

          lua_rawset(L, 1);

          return 0;
      } else {

          int             _index = lua_tonumber(L, -1);

          lua_pushnumber(L, 0);
          lua_rawget(L, 1);

          T             **obj =
        static_cast < T ** >(lua_touserdata(L, -1));

          lua_pushvalue(L, 3);

          //const PropertyType *_properties = (*obj)->T::Properties;

          return ((*obj)->*(T::Properties[_index].setter)) (L);

      }

    }

    static int  function_dispatch(lua_State * L) {

      int i = (int) lua_tonumber(L, lua_upvalueindex(1));

      lua_pushnumber(L, 0);
      lua_rawget(L, 1);

      T             **obj = static_cast < T ** >(lua_touserdata(L, -1));

      lua_pop(L, 1);

      return ((*obj)->*(T::Functions[i].function)) (L);
    }

    static int      gc_obj(lua_State * L) {

      T             **obj =
          static_cast < T ** >(luaL_checkudata(L, -1, T::className));

      if (!(*obj)->isExisting && !(*obj)->isPrecious)
      {
        cout << "Cleaning up a " << T::className << "." << endl;
        delete(*obj);
      }

      return 0;
    }


private:

/*
    moLuna();  // hide default constructor


    // member function dispatcher
    static int thunk(lua_State *L) {
        // stack has userdata, followed by method args
        T *obj = check(L, 1);  // get 'self', or if you prefer, 'this'
        lua_remove(L, 1);  // remove self so member function args start at index 1
        // get member function from upvalue
        RegType *l = static_cast<RegType*>(lua_touserdata(L, lua_upvalueindex(1)));
        return (obj->*(l->mfunc))(L);  // call member function
    }

    // create a new T object and
    // push onto the Lua stack a userdata containing a pointer to T object
    static int new_T(lua_State *L) {
        lua_remove(L, 1);   // use classname:new(), instead of classname.new()
        T *obj = new T(L);  // call constructor for T objects
        userdataType *ud =
            static_cast<userdataType*>(lua_newuserdata(L, sizeof(userdataType)));
        ud->pT = obj;  // store pointer to object in userdata
        luaL_getmetatable(L, T::className);  // lookup metatable in Lua registry
        lua_setmetatable(L, -2);
        return 1;  // userdata containing pointer to T object
    }

    // garbage collection metamethod
    static int gc_T(lua_State *L) {
        userdataType *ud = static_cast<userdataType*>(lua_touserdata(L, 1));
        T *obj = ud->pT;
        if ( obj )
        {
            delete obj;  // call destructor for T objects
            obj = 0;
        }
        return 0;
    }

    static int tostring_T (lua_State *L) {
        char buff[32];
        userdataType *ud = static_cast<userdataType*>(lua_touserdata(L, 1));
        T *obj = ud->pT;
        sprintf(buff, "%p", obj);
        lua_pushfstring(L, "%s (%s)", T::className, buff);
        return 1;
    }
    */
};

#define DECLARE_SCRIPT_CLASS(ClassName)                 \
    public:                                             \
    static const char className[];                      \
    static moLuna<ClassName>::PropertyType Properties[]; \
    static moLuna<ClassName>::FunctionType Functions[];\
\
    bool isExisting; \
  bool isPrecious;


#define IMPLEMENT_SCRIPT_CLASS(ClassName)               \
    const char ClassName::className[] = #ClassName;

#define DEFINE_SCRIPT_CLASS_FUNCTIONS(ClassName)                        \
    moLuna<ClassName>::FunctionType ClassName::Functions[] = {

#define SCRIPT_FUNCTION(ClassName, FunctionName) { #FunctionName, &ClassName::FunctionName }

#define END_SCRIPT_CLASS_FUNCTIONS };


#define DEFINE_SCRIPT_CLASS_PROPERTIES(ClassName)                       \
    moLuna<ClassName>::PropertyType ClassName::Properties[] = {

#define SCRIPT_PROPERTY(ClassName, PropertyName, PropertyGetter, PropertySetter ) { #PropertyName, &ClassName::PropertyGetter, &ClassName::PropertySetter }

#define END_SCRIPT_CLASS_PROPERTIES };

#define REGISTER_CLASS(ClassName, LuaState)                 \
    moLuna<ClassName>::Register(LuaState);

#define SCRIPT_CONSTRUCTOR_DECLARATION(ClassName) ClassName(lua_State* L);
#define SCRIPT_CONSTRUCTOR_IMPLEMENTATION(ClassName) ClassName::ClassName(lua_State* L)

#define SCRIPT_FUNCTION_DECLARATION(FunctionName) int FunctionName(lua_State* L);
#define SCRIPT_FUNCTION_IMPLEMENTATION(ClassName, FunctionName) int ClassName::FunctionName(lua_State* L)

#endif