source: orxonox.OLD/branches/script_engine/src/lib/script_engine/LuaCallback.h @ 7645

#ifndef __LUA_CALLBACK_H__
#define __LUA_CALLBACK_H__

#include <assert.h>
#include <string>
#include <iostream>
#include <stdio.h>

class LuaVirtualMachine;


/**
 * @brief This function accually executes a method called by Lua.
 *
 * @param lua Since this function gets called by lua it has to have a lua_State as parameter
 *
 * @return the number of return values. (which can be found on the stack)
 *
 * For Lua doesn't know how to handle C++ objects it pushes the Objecttable (including the objectpointer) on top of the stack and
 * calls this function.
 *
 *
 * @todo handle an acces to a nonexistent (deleted) object
 */


static int luaCallback (lua_State *lua)
{

 // Locate the psudo-index for the function number
  int methodNumber = lua_upvalueindex (1);
  int returnCount = 0;

  bool functionSuccess = false;

 // Check for the "this" table
  if (lua_istable (lua, 1))
  {
   // Found the "this" table. The object pointer is at the index 0
    lua_rawgeti (lua, 1, 0);

    if (lua_islightuserdata (lua, -1))
    {
     // Found the pointer, need to cast it
      Scriptable* thisPointer = (Scriptable*) lua_touserdata (lua, -1);

      // Get the method index
      int methodIndex = (int) lua_tonumber (lua, methodNumber);

     // Reformat the stack so our parameters are correct
     // Clean up the "this" table
      lua_remove (lua, 1);
     // Clean up the thisPointer pointer
      lua_remove (lua, -1);

      //debug
      //std::cout<<thisPointer->whatIsThis()<<std::endl;

      LuaScript* originScript = NULL;

      lua_getglobal (lua, "this");

      if (lua_istable (lua, 1))
      {
   // Found the "this" table. The object pointer is at the index 0
        lua_rawgeti (lua, 1, 0);

        if (lua_islightuserdata (lua, -1))
        {
     // Found the pointer, need to cast it
           originScript = (LuaScript *) lua_touserdata (lua, -1);
        }
      }

      if(originScript == NULL)
      {//do something usefull
      }
      //debug
     // std::cout<<originScript->whatIsThis()<<std::endl;

      LuaVirtualMachine virtualMachine = originScript->getVirtualMachine();
      //debug
      //std::cout<<"test "<< thisPointer->methods(virtualMachine)<<std::endl;
      // Check that the method is correct index
      assert ((methodIndex <= thisPointer->methods(virtualMachine) ));
      // Call the class
      returnCount = thisPointer->scriptCalling ( virtualMachine, thisPointer->getFunctionAtIndex(methodIndex,virtualMachine));

      functionSuccess = true;
    }
  }

  if (functionSuccess == false)
  {
    lua_pushstring (lua, "luaCallback -> Failed to call the class function");
    lua_error (lua);
  }

   // Number of return variables
  return returnCount;
}

#endif /* __LUA_CALLBACK_H__*/