rtt.cpp

/*
 * Lua-RTT bindings
 *
 * (C) Copyright 2010 Markus Klotzbuecher
 * markus.klotzbuecher@mech.kuleuven.be
 * Department of Mechanical Engineering,
 * Katholieke Universiteit Leuven, Belgium.
 *
 * This library 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;
 * version 2 of the License.
 *
 * As a special exception, you may use this file as part of a free
 * software library without restriction.  Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License.  This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU General
 * Public License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place,
 * Suite 330, Boston, MA  02111-1307  USA
 */

#include "rtt.hpp"

using namespace std;
using namespace RTT;
using namespace RTT::detail;
using namespace RTT::base;
using namespace RTT::internal;

static TaskContext* __getTC(lua_State*);

#define DEBUG

#ifdef MSVC
#ifdef DEBUG
# define _DBG(fmt, ...) printf("%s:%d\t" fmt "\n", __FUNCTION__, __LINE__, __VA_ARGS__)
#else
# define _DBG(fmt, ...) do { } while(0);
#endif
#else
#ifdef DEBUG
# define _DBG(fmt, args...) printf("%s:%d\t" fmt "\n", __FUNCTION__, __LINE__, ##args)
#else
# define _DBG(fmt, args...) do { } while(0);
#endif
#endif

/*
 * Inspired by tricks from here: http://lua-users.org/wiki/DoItYourselfCppBinding
 */

/* overloading new */
void* operator new(size_t size, lua_State* L, const char* mt)
{
    void* ptr = lua_newuserdata(L, size);
    luaL_getmetatable(L, mt);
    /* assert(lua_istable(L, -1)) */  /* if you're paranoid */
    lua_setmetatable(L, -2);
    return ptr;
}

/*
 * luaM_pushobject_mt(L, "Port", InputPortInterface )(ctr_arg,...)
 * expands to
 * new(L, "Port") InputPortInterface(ctr_arg,...)
 */

#define luaM_pushobject(L, T) new(L, #T) T
#define luaM_pushobject_mt(L, MT, T) new(L, MT) T

/* return udata ptr or fail if wrong metatable */
#define luaM_checkudata(L, pos, T) reinterpret_cast<T*>(luaL_checkudata((L), (pos), #T))
#define luaM_checkudata_mt(L, pos, MT, T) reinterpret_cast<T*>(luaL_checkudata((L), (pos), MT))

/* return udata ptr or NULL if wrong metatable */
#define luaM_testudata(L, pos, T) (T*) (luaL_testudata((L), (pos), #T))
#define luaM_testudata_mt(L, pos, MT, T) (T*) (luaL_testudata((L), (pos), MT))

/*
 * boxed variants
 */

/* return boxed udata ptr or fail if wrong metatable */
#define luaM_checkudata_bx(L, pos, T) (T**) (luaL_checkudata((L), (pos), #T))
#define luaM_checkudata_mt_bx(L, pos, MT, T) (T**) (luaL_checkudata((L), (pos), MT))

/* return udata ptr or NULL if wrong metatable */
#define luaM_testudata_bx(L, pos, T) (T**) (luaL_testudata((L), (pos), #T))
#define luaM_testudata_mt_bx(L, pos, MT, T) (T**) (luaL_testudata((L), (pos), MT))

/* generate a function to push boxed pointers to lua */
#define gen_push_bxptr(name, MT, T)            \
static void name(lua_State *L, T* ptr)             \
{                              \
    T** ptrptr = (T**) lua_newuserdata(L, sizeof(T*)); \
    *ptrptr = ptr;                     \
    luaL_getmetatable(L, MT);              \
    lua_setmetatable(L, -2);               \
}                              \

/* template for generating GC function */
template<typename T>
int GCMethod(lua_State* L)
{
    reinterpret_cast<T*>(lua_touserdata(L, 1))->~T();
    return 0;
}


/***************************************************************
 * Some generic helpers
 ***************************************************************/

/* test if userdata on position ud has metatable tname */
void* luaL_testudata (lua_State *L, int ud, const char *tname)
{
    void *p = lua_touserdata(L, ud);

    if (p == NULL)
        goto out;

    if (!lua_getmetatable(L, ud))  {
        p = NULL;
        goto out;
    }

    /* it has a MT, is it the right one? */
    lua_pushstring(L, tname);
    lua_rawget(L, LUA_REGISTRYINDEX);

    if (!lua_rawequal(L, -1, -2))
        p = NULL;

    lua_pop(L, 2);  /* remove both metatables */
 out:
    return p;
}


void push_vect_str(lua_State *L, const std::vector<std::string> &v)
{
    int key = 1;
    lua_createtable(L, v.size(), 0);

    for(vector<std::string>::const_iterator it = v.begin(); it != v.end(); ++it) {
        lua_pushstring(L, it->c_str());
        lua_rawseti(L, -2, key++);
    }
}

/* forw decl */
static void Variable_fromlua(lua_State *L, DataSourceBase::shared_ptr& dsb, int valind);
static DataSourceBase::shared_ptr Variable_fromlua(lua_State *L, const types::TypeInfo* ti, int valind);
static DataSourceBase::shared_ptr Variable_fromlua(lua_State *L, const char* type, int valind);

/***************************************************************
 * Variable (DataSourceBase)
 ***************************************************************/

static const TypeInfo* ti_lookup(lua_State *L, const char *name)
{
#ifndef TYPEINFO_CACHING
    return types::TypeInfoRepository::Instance()->type(name);
#else
/* name-> TypeInfo* cache */
    int top = lua_gettop(L);
    const TypeInfo* ti;

    /* try lookup */
    lua_pushstring(L, "typeinfo_cache");
    lua_rawget(L, LUA_REGISTRYINDEX);

    if(lua_type(L, -1) == LUA_TTABLE)
        goto table_on_top;

    /* first lookup, create table */
    lua_pop(L, 1); /* pop nil */
    lua_newtable(L); /* stays on top after the next three lines */
    lua_pushstring(L, "typeinfo_cache"); /* key */
    lua_pushvalue(L, -2); /* duplicates table */
    lua_rawset(L, LUA_REGISTRYINDEX);   /* REG['typeinfo_cache']={} */

 table_on_top:
    /* try to lookup name in table */
    lua_pushstring(L, name);
    lua_rawget(L, -2);

    if(lua_type(L, -1) != LUA_TLIGHTUSERDATA)
        goto cache_miss;

    ti = (const TypeInfo*) lua_touserdata(L, -1);
    goto out;

 cache_miss:
    lua_pop(L, 1); /* pop the nil */
    ti = types::TypeInfoRepository::Instance()->type(name);
    if (ti) { // only save if type exists !
        lua_pushstring(L, name);
        lua_pushlightuserdata(L, (void*) ti);
        lua_rawset(L, -3);
    }
 out:
    /* everyone happy! */
    lua_settop(L, top);
    return ti;
#endif /* TYPEINFO_CACHING */
}

/* helper, check if a type name is an alias to the given TypeInfo */
static bool __typenames_cmp(lua_State *L, const types::TypeInfo *ti1, const char* type2)
{
    const types::TypeInfo *ti2 = ti_lookup(L, type2);
    return ti1 == ti2;
}

/* helper, check if a dsb is of type type. Works also if dsb is known
   under an alias of type */
static bool Variable_is_a(lua_State *L, const types::TypeInfo *ti1, const char* type)
{
    const types::TypeInfo *ti2 = ti_lookup(L, type);
    return ti1 == ti2;
}

/* helper, check if a variable is basic, that is _tolua will succeed */
static bool __Variable_isbasic(lua_State *L, DataSourceBase::shared_ptr &dsb)
{
    const types::TypeInfo *ti = dsb->getTypeInfo();

    if ( Variable_is_a(L, ti, "bool") ||
         Variable_is_a(L, ti, "double") ||
         Variable_is_a(L, ti, "float") ||
         Variable_is_a(L, ti, "uint") ||
         Variable_is_a(L, ti, "int") ||
         Variable_is_a(L, ti, "long") ||
         Variable_is_a(L, ti, "char") ||
         Variable_is_a(L, ti, "uint8") || Variable_is_a(L, ti, "int8") ||
         Variable_is_a(L, ti, "uint16") || Variable_is_a(L, ti, "int16") ||
         Variable_is_a(L, ti, "uint32") || Variable_is_a(L, ti, "int32") ||
         Variable_is_a(L, ti, "uint64") || Variable_is_a(L, ti, "int64") ||
         Variable_is_a(L, ti, "string") ||
         Variable_is_a(L, ti, "void"))
        return true;
    else
        return false;
}

static int Variable_isbasic(lua_State *L)
{
    DataSourceBase::shared_ptr dsb = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr));
    lua_pushboolean(L, __Variable_isbasic(L, dsb));
    return 1;
}


/*
 * converts a DataSourceBase to the corresponding Lua value and pushes
 * that on the stack.
 */
static int __Variable_tolua(lua_State *L, DataSourceBase::shared_ptr dsb)
{
    DataSourceBase *ds = dsb.get();
    const types::TypeInfo* ti = dsb->getTypeInfo();
    assert(ds);

    if(Variable_is_a(L, ti, "bool")) { // bool
        DataSource<bool>* dsb = DataSource<bool>::narrow(ds);
        if(dsb) lua_pushboolean(L, dsb->get());
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "float")) { // float
        DataSource<float>* dsb = DataSource<float>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "double")) { // double
        DataSource<double>* dsb = DataSource<double>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "uint8")) { // uint8_t
        DataSource<uint8_t>* dsb = DataSource<uint8_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "int8")) { // int8_t
        DataSource<int8_t>* dsb = DataSource<int8_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "uint16")) { // uint16_t
        DataSource<uint16_t>* dsb = DataSource<uint16_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "int16")) { // int16_t
        DataSource<int16_t>* dsb = DataSource<int16_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "uint32")) { // uint32_t
        DataSource<uint32_t>* dsb = DataSource<uint32_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "int32")) { // int32_t
        DataSource<int32_t>* dsb = DataSource<int32_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "uint64")) { // uint64_t
        DataSource<uint64_t>* dsb = DataSource<uint64_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "int64")) { // int64_t
        DataSource<int64_t>* dsb = DataSource<int64_t>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "uint")) { // uint
        DataSource<unsigned int>* dsb = DataSource<unsigned int>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "long")) { //long
        DataSource<long>* dsb = DataSource<long>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "int")) { // int
        DataSource<int>* dsb = DataSource<int>::narrow(ds);
        if(dsb) lua_pushnumber(L, ((lua_Number) dsb->get()));
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "char")) { // char
        DataSource<char>* dsb = DataSource<char>::narrow(ds);
        char c = dsb->get();
        if(dsb) lua_pushlstring(L, &c, 1);
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "string")) { //string
        DataSource<std::string>* dsb = DataSource<std::string>::narrow(ds);
        if(dsb) lua_pushlstring(L, dsb->get().c_str(), dsb->get().size());
        else goto out_nodsb;
    } else if (Variable_is_a(L, ti, "void")) {
        DataSource<void>* dsb = DataSource<void>::narrow(ds);
        if(dsb) lua_pushnil(L);
        else goto out_nodsb;
    } else {
        goto out_conv_err;
    }

    /* all ok */
    return 1;

 out_conv_err:
    luaL_error(L, "Variable.tolua: can't convert type %s", dsb->getTypeName().c_str());
    return 0;

 out_nodsb:
    luaL_error(L, "Variable.tolua: narrow failed for %s Variable", dsb->getTypeName().c_str());
    return 0;
}

static int Variable_tolua(lua_State *L)
{
    DataSourceBase::shared_ptr dsb = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr));
    return __Variable_tolua(L, dsb);
}

/* Function takes a DSB, that is also expected on the top of the
 * stack. If the DSB is basic, it replaces the dsb with the
 * corresponding Lua value. Otherwise it does nothing, leaving the DSB
 * on the top of the stack.
 */
static void Variable_coerce(lua_State *L, DataSourceBase::shared_ptr dsb)
{
    if (__Variable_isbasic(L, dsb)) {
        lua_pop(L, 1);
        __Variable_tolua(L, dsb);
    }
}

/* this function takes a dsb and either pushes it as a Lua type if the
 * dsb is basic or otherwise as at Variable
 */
static void Variable_push_coerce(lua_State *L, DataSourceBase::shared_ptr dsb)
{
    if (__Variable_isbasic(L, dsb))
        __Variable_tolua(L, dsb);
    else
        luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(dsb);

}

static int Variable_getTypes(lua_State *L)
{
    push_vect_str(L, Types()->getTypes());
    return 1;
}

static int Variable_getMemberNames(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    push_vect_str(L, (*dsbp)->getMemberNames());
    return 1;
}

static int Variable_tolightuserdata(lua_State *L)
{
    DataSourceBase::shared_ptr dsb = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr));
    lua_pushlightuserdata(L, dsb->getRawPointer());
    return 1;
}


/* caching of DSB members
 * lookup of DSB using getMember and caches result.
 * returns DSB (or nil if lookup fails) on top of stack.
 */
static DataSourceBase::shared_ptr lookup_member(lua_State *L, DataSourceBase::shared_ptr parent, const char* mem)
{
    DataSourceBase *varptr;
    DataSourceBase::shared_ptr *dsbp;
    DataSourceBase::shared_ptr memdsb;
    int top = lua_gettop(L);

    varptr = parent.get();

    lua_pushlightuserdata(L, (void*) varptr);
    lua_rawget(L, LUA_REGISTRYINDEX);

    if(lua_type(L, -1) == LUA_TNIL)
        goto cache_miss;

    lua_pushstring(L, mem);
    lua_rawget(L, -2);

    if ((dsbp = luaM_testudata_mt(L, -1, "Variable", DataSourceBase::shared_ptr)) != NULL) {
        memdsb=*dsbp;
        goto out;
    }

    lua_pop(L, 1); /* pop nil from table lookup */

 cache_miss:
    /* slowpath */
    memdsb = parent->getMember(mem);

    if(memdsb == 0)
        goto out;

    /* if nil is on top of stack, we have to create a new table */
    if(lua_type(L, -1) == LUA_TNIL) {
        lua_newtable(L);                /* member lookup tab for this Variable */
        lua_pushlightuserdata(L, (void*) varptr); /* index for REGISTRY */
        lua_pushvalue(L, -2);           /* duplicates table */
        lua_rawset(L, LUA_REGISTRYINDEX);   /* REG[varptr]=newtab */
    }

    /* cache dsb in table */
    lua_pushstring(L, mem);
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(memdsb);
    lua_rawset(L, -3);          /* newtab[mem]=memdsb, top is newtab */
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(memdsb);

 out:
    lua_replace(L, top+1); // make new var top of stack
    lua_settop(L, top+1);

    return memdsb;
}

/* set reg[varptr] to nil so table will be garbage collected */
static void cache_clear(lua_State *L, DataSourceBase *varptr)
{
    lua_pushlightuserdata(L, (void*) varptr);
    lua_pushnil(L);
    lua_rawset(L, LUA_REGISTRYINDEX);
}

static int Variable_getMember(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    DataSourceBase::shared_ptr memdsb;
    const char *mem = luaL_checkstring(L, 2);

    if ((memdsb = lookup_member(L, *dsbp, mem)) == 0)
        luaL_error(L, "Variable.getMember: indexing failed, no member %s", mem);
    else
        Variable_coerce(L, memdsb);

    return 1;
}

static int Variable_getMemberRaw(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    DataSourceBase::shared_ptr memdsb;
    const char *mem = luaL_checkstring(L, 2);

    if ((memdsb = lookup_member(L, (*dsbp), mem)) == 0)
        luaL_error(L, "Variable.getMemberRaw: indexing failed, no member %s", mem);

    /* else: Variable is already on top of stack */

    return 1;
}

static int Variable_update(lua_State *L)
{
    int ret;
    DataSourceBase::shared_ptr dsb;
    DataSourceBase::shared_ptr *dsbp;
    DataSourceBase::shared_ptr self = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr));

    if ((dsbp = luaM_testudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)) != NULL) {
        dsb = *dsbp;
        ret = self->update(dsb.get());
        if (!ret) luaL_error(L, "Variable.assign: assignment failed");
    } else {
        Variable_fromlua(L, self, 2);
    }

    return 0;
}

/* create variable */
static int Variable_create(lua_State *L)
{
    const char *type;
    type = luaL_checkstring(L, 1);

    if(!strcmp(type, "void"))
        luaL_error(L, "Variable.new: can't create void variable");

    TypeInfo* ti = Types()->type(type);

    if(ti==0)
        luaL_error(L, "Variable.new: unknown type %s", type);

    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(ti->buildValue());
    return 1;
}

#define CONVERT_TO_NUMBER(CTGT) \
    lua_Number x; \
    if (luatype == LUA_TNUMBER) x = lua_tonumber(L, valind); \
    else goto out_conv_err; \
    AssignableDataSource<CTGT> *ads = ValueDataSource<CTGT>::narrow(dsb.get()); \
    if (ads == NULL) luaL_error(L, "Variable_fromlua: failed to narrow target dsb to %s.", #CTGT ); \
    ads->set((CTGT) x)\

/* Try to convert the Lua value on stack at valind to given DSB
 * if it returns, evertthing is ok */
static void Variable_fromlua(lua_State *L, DataSourceBase::shared_ptr& dsb, int valind)
{
    const types::TypeInfo* ti = dsb->getTypeInfo();

    luaL_checkany(L, valind);
    int luatype = lua_type(L, valind);  /* type of lua variable */

    if(__typenames_cmp(L, ti, "bool")) {
        lua_Number x;
        if(luatype == LUA_TBOOLEAN)
            x = (lua_Number) lua_toboolean(L, valind);
        else if (luatype == LUA_TNUMBER)
            x = lua_tonumber(L, valind);
        else
            goto out_conv_err;

        AssignableDataSource<bool> *ads = ValueDataSource<bool>::narrow(dsb.get());
        if (ads == NULL)
            luaL_error(L, "Variable_fromlua: failed to narrow target dsb to bool");
        ads->set((bool) x);
    }
    else if (__typenames_cmp(L, ti, "uint"))   { CONVERT_TO_NUMBER(unsigned int); }
    else if (__typenames_cmp(L, ti, "int"))    { CONVERT_TO_NUMBER(int); }
    else if (__typenames_cmp(L, ti, "double")) { CONVERT_TO_NUMBER(double); }
    else if (__typenames_cmp(L, ti, "long"))   { CONVERT_TO_NUMBER(double); }
    else if (__typenames_cmp(L, ti, "uint8"))  { CONVERT_TO_NUMBER(uint8_t); }
    else if (__typenames_cmp(L, ti, "int8"))   { CONVERT_TO_NUMBER(int8_t); }
    else if (__typenames_cmp(L, ti, "uint16")) { CONVERT_TO_NUMBER(uint16_t); }
    else if (__typenames_cmp(L, ti, "int16"))  { CONVERT_TO_NUMBER(int16_t); }
    else if (__typenames_cmp(L, ti, "uint32")) { CONVERT_TO_NUMBER(uint32_t); }
    else if (__typenames_cmp(L, ti, "int32"))  { CONVERT_TO_NUMBER(int32_t); }
    else if (__typenames_cmp(L, ti, "uint64")) { CONVERT_TO_NUMBER(uint64_t); }
    else if (__typenames_cmp(L, ti, "int64"))  { CONVERT_TO_NUMBER(int64_t); }
    else if (__typenames_cmp(L, ti, "float"))  { CONVERT_TO_NUMBER(float); }

    else if (__typenames_cmp(L, ti, "char")) {
        const char *x;
        size_t l;
        if (luatype == LUA_TSTRING) x = lua_tolstring(L, valind, &l);
        else goto out_conv_err;
        AssignableDataSource<char> *ads = ValueDataSource<char>::narrow(dsb.get());
        if (ads == NULL) luaL_error(L, "Variable_fromlua: failed to narrow target dsb to char");
        ads->set((char) x[0]);

    } else if (__typenames_cmp(L, ti, "string")) {
        const char *x;
        if (luatype == LUA_TSTRING) x = lua_tostring(L, valind);
        else goto out_conv_err;
        AssignableDataSource<std::string> *ads = ValueDataSource<std::string>::narrow(dsb.get());
        if (ads == NULL) luaL_error(L, "Variable_fromlua: failed to narrow target dsb to std::string");
        ads->set((std::string) x);

    } else {
        goto out_conv_err;
    }

    /* everybody happy */
    return;

 out_conv_err:
    luaL_error(L, "__lua_todsb: can't convert lua %s to %s variable",
           lua_typename(L, luatype), ti->getTypeName().c_str());
    return;
}

/* Create a DSB of RTT ti from the Lua value at stack[valind]
 * This one will create a dsb - NRT!*/
static DataSourceBase::shared_ptr Variable_fromlua(lua_State *L, const types::TypeInfo *ti, int valind)
{
    DataSourceBase::shared_ptr dsb = ti->buildValue();
    Variable_fromlua(L, dsb, valind);
    return dsb;
}

/* Create a DSB of RTT type 'type' from the Lua value at stack[valind]
 * This one will create a dsb - NRT!
 * This one should be avoided, to reduce needless name-ti lookups.
 * preferred variant is the one taking TypeInfo * as second arg */
static DataSourceBase::shared_ptr Variable_fromlua(lua_State *L, const char* type, int valind)
{
    const types::TypeInfo* ti = ti_lookup(L, type);
    if(!ti) luaL_error(L, "Variable_fromlua: %s is not a known type. Load typekit?", type);
    return Variable_fromlua(L, ti, valind);
}


static int Variable_create_ival(lua_State *L, int typeind, int valind)
{
    DataSourceBase::shared_ptr dsb;
    luaL_checkany(L, valind);
    const char* type = luaL_checkstring(L, typeind);    /* target dsb type */
    dsb = Variable_fromlua(L, type, valind);
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(dsb);
    return 1;
}

static int Variable_new(lua_State *L)
{
    int argc = lua_gettop(L);
    if(argc == 1)
        return Variable_create(L);
    else if(argc == 2)
        return Variable_create_ival(L, 1, 2);
    else
        luaL_error(L, "Variable.new: invalid number of args");

    return 0;
}

static int Variable_toString(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    lua_pushstring(L, ((*dsbp)->toString()).c_str());
    return 1;
}

static int Variable_getType(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    lua_pushstring(L, (*dsbp)->getType().c_str());
    return 1;
}

static int Variable_getTypeIdName(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    lua_pushstring(L, (*dsbp)->getTypeInfo()->getTypeIdName());
    return 1;
}

static int Variable_getTypeName(lua_State *L)
{
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    lua_pushstring(L, (*dsbp)->getTypeName().c_str());
    return 1;
}

static int Variable_resize(lua_State *L)
{
    int size;
    DataSourceBase::shared_ptr *dsbp = luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr);
    size = luaL_checknumber(L, 2);
    const TypeInfo *ti = (*dsbp)->getTypeInfo();
    lua_pushboolean(L, ti->resize(*dsbp, size));
    return 1;
}


/*
 * Operators
 */
static int Variable_unm(lua_State *L)
{
    types::OperatorRepository::shared_ptr opreg = types::OperatorRepository::Instance();
    DataSourceBase::shared_ptr arg = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr));
    DataSourceBase::shared_ptr res = opreg->applyUnary("-", arg.get());
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(res);
    return 1;
}


/* don't try this at home */
#define gen_opmet(name, op)                 \
static int name(lua_State *L)                   \
{                               \
    DataSourceBase::shared_ptr arg1 = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr)); \
    DataSourceBase::shared_ptr arg2 = *(luaM_checkudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)); \
    types::OperatorRepository::shared_ptr opreg = types::OperatorRepository::Instance(); \
    DataSourceBase *res = opreg->applyBinary(#op, arg1.get(), arg2.get()); \
    if(res == 0)                            \
        luaL_error(L , "%s (operator %s) failed", #name, #op);  \
    res->evaluate();                        \
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(res); \
    return 1;                           \
}                                   \

gen_opmet(Variable_add, +)
gen_opmet(Variable_sub, -)
gen_opmet(Variable_mul, *)
gen_opmet(Variable_div, /)
gen_opmet(Variable_mod, %)
gen_opmet(Variable_pow, ^)

/* these flavors convert the boolean return dsb to a lua bool */
#define gen_opmet_bool(name, op)                \
static int name(lua_State *L)                   \
{                               \
    DataSourceBase::shared_ptr arg1 = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr)); \
    DataSourceBase::shared_ptr arg2 = *(luaM_checkudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)); \
    types::OperatorRepository::shared_ptr opreg = types::OperatorRepository::Instance(); \
    DataSourceBase *res = opreg->applyBinary(#op, arg1.get(), arg2.get()); \
    if(res == 0)                            \
        luaL_error(L , "%s (operator %s) failed", #name, #op);  \
    res->evaluate();                        \
    return __Variable_tolua(L, res);                \
}                                   \

gen_opmet_bool(Variable_eq, ==)
gen_opmet_bool(Variable_lt, <)
gen_opmet_bool(Variable_le, <=)

static int Variable_opBinary(lua_State *L)
{
    types::OperatorRepository::shared_ptr opreg = types::OperatorRepository::Instance();
    const char *op = luaL_checkstring(L, 1);
    DataSourceBase::shared_ptr arg1 = *(luaM_checkudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr));
    DataSourceBase::shared_ptr arg2 = *(luaM_checkudata_mt(L, 3, "Variable", DataSourceBase::shared_ptr));
    DataSourceBase *res;

    res = opreg->applyBinary(op, arg1.get(), arg2.get());
    if(res == 0)
        luaL_error(L , "Variable.opBinary '%s' not applicable to args", op);

    res->evaluate();

    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(res);
    return 1;
}

/*
 * this is a dispatcher which checks if the key is a method, otherwise
 * calls get for looking up the field. Inspired by
 * http://lua-users.org/wiki/ObjectProperties
 */
static int Variable_index(lua_State *L)
{
    const char* key = luaL_checkstring(L, 2);

    lua_getmetatable(L, 1);
    lua_getfield(L, -1, key);

    /* Either key is name of a method in the metatable */
    if(!lua_isnil(L, -1))
        return 1;

    /* ... or its a field access, so recall as self.get(self, value). */
    lua_settop(L, 2);
    return Variable_getMember(L);
}

static int Variable_newindex(lua_State *L)
{
    DataSourceBase::shared_ptr *newvalp;
    DataSourceBase::shared_ptr newval;
    DataSourceBase::shared_ptr parent = *(luaM_checkudata_mt(L, 1, "Variable", DataSourceBase::shared_ptr));
    const char* mem = luaL_checkstring(L, 2);

    /* get dsb to be updated: we need its type before get-or-create'ing arg3 */
    types::OperatorRepository::shared_ptr opreg = types::OperatorRepository::Instance();
    DataSourceBase::shared_ptr curval;

    if ((curval = lookup_member(L, parent, mem)) == 0)
        luaL_error(L, "Variable.newindex: indexing failed, no member %s", mem);


    /* assigning a DSB */
    if ((newvalp = luaM_testudata_mt(L, 3, "Variable", DataSourceBase::shared_ptr)) != NULL) {
        newval = *newvalp;
        if(!curval->update(newval.get())) {
            luaL_error(L, "Variable.newindex: failed to assign %s to member %s of type %s",
                   newval->getType().c_str(), mem, curval->getType().c_str());
        }
    } else /* assigning basic type */
        Variable_fromlua(L, curval, 3);
    return 1;
}

// Why doesn't the following work:
// static int Variable_gc(lua_State *L)
// {
//  DataSourceBase::shared_ptr *dsbp = (DataSourceBase::shared_ptr*) lua_touserdata(L, 1);
//  cache_clear(L, dsbp->get());
//  dsbp->~DataSourceBase::shared_ptr();
//  return 0;
// }

template<typename T>
int VariableGC(lua_State* L)
{
    T* dsbp = (T*) lua_touserdata(L, 1);
    cache_clear(L, dsbp->get());
    reinterpret_cast<T*>(dsbp)->~T();
    return 0;
}


static const struct luaL_Reg Variable_f [] = {
    { "new", Variable_new },
    { "tolua", Variable_tolua },
    { "isbasic", Variable_isbasic },
    { "toString", Variable_toString },
    { "getTypes", Variable_getTypes },
    { "getType", Variable_getType },
    { "getTypeName", Variable_getTypeName },
    { "getTypeIdName", Variable_getTypeIdName },
    { "getMemberNames", Variable_getMemberNames },
    { "getMember", Variable_getMember },
    { "getMemberRaw", Variable_getMemberRaw },
    { "tolud", Variable_tolightuserdata },
    { "resize", Variable_resize },
    { "opBinary", Variable_opBinary },
    { "assign", Variable_update }, /* assign seems a better name than update */
    { "unm", Variable_unm },
    { "add", Variable_add },
    { "sub", Variable_sub },
    { "mul", Variable_mul },
    { "div", Variable_div },
    { "mod", Variable_mod },
    { "pow", Variable_pow },
    { "eq", Variable_eq },
    { "lt", Variable_lt },
    { "le", Variable_le },
    { NULL, NULL}
};

static const struct luaL_Reg Variable_m [] = {
    { "tolua", Variable_tolua },
    { "isbasic", Variable_isbasic },
    { "toString", Variable_toString },
    { "getType", Variable_getType },
    { "getTypeName", Variable_getTypeName },
    { "getTypeIdName", Variable_getTypeIdName },
    { "getMemberNames", Variable_getMemberNames },
    { "getMember", Variable_getMember },
    { "getMemberRaw", Variable_getMemberRaw },
    { "tolud", Variable_tolightuserdata },
    { "resize", Variable_resize },
    { "opBinary", Variable_opBinary },
    { "assign", Variable_update }, /* assign seems a better name than update */
    { "__unm", Variable_unm },
    { "__add", Variable_add },
    { "__sub", Variable_sub },
    { "__mul", Variable_mul },
    { "__div", Variable_div },
    { "__mod", Variable_mod },
    { "__pow", Variable_pow },
    { "__eq", Variable_eq },
    { "__lt", Variable_lt },
    { "__le", Variable_le },
    { "__index", Variable_index },
    { "__newindex", Variable_newindex },
    // { "__gc", GCMethod<DataSourceBase::shared_ptr> },
    // {"__gc", Variable_gc},
    {"__gc", VariableGC<DataSourceBase::shared_ptr> },
    { NULL, NULL}
};


/***************************************************************
 * Property (boxed)
 ***************************************************************/

gen_push_bxptr(Property_push, "Property", PropertyBase)

static int Property_new(lua_State *L)
{
    const char *type, *name, *desc;
    PropertyBase *pb;
    int argc = lua_gettop(L);
    type = luaL_checkstring(L, 1);

    /* name and description are optional */
    name = (argc > 1) ? luaL_checkstring(L, 2) : "";
    desc = (argc > 2) ? luaL_checkstring(L, 3) : "";

    types::TypeInfo *ti = types::TypeInfoRepository::Instance()->type(type);

    if(!ti)
        luaL_error(L, "Property.new: unknown type %s", type);

    pb =  ti->buildProperty(name, desc);
    Property_push(L, pb);
    return 1;
}

static int Property_get(lua_State *L)
{
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Property", PropertyBase));
    Variable_push_coerce(L, pb->getDataSource());
    return 1;
}

static int Property_getRaw(lua_State *L)
{
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Property", PropertyBase));
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(pb->getDataSource());
    return 1;
}

static int Property_set(lua_State *L)
{
    DataSourceBase::shared_ptr newdsb;
    DataSourceBase::shared_ptr *newdsbp;
    DataSourceBase::shared_ptr propdsb;
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Property", PropertyBase));
    propdsb = pb->getDataSource();

    /* assigning a DSB */
    if ((newdsbp = luaM_testudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)) != NULL) {
        newdsb = *newdsbp;
        if(!propdsb->update(newdsb.get()))
            luaL_error(L, "Property.set: failed to assign type %s to type %s",
                   newdsb->getType().c_str(), propdsb->getType().c_str());
    } else { /* assigning a Lua value */
        Variable_fromlua(L, propdsb, 2);
    }
    return 1;
}

static int Property_info(lua_State *L)
{
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Property", PropertyBase));
    lua_newtable(L);
    lua_pushstring(L, "name"); lua_pushstring(L, pb->getName().c_str()); lua_rawset(L, -3);
    lua_pushstring(L, "desc"); lua_pushstring(L, pb->getDescription().c_str()); lua_rawset(L, -3);
    lua_pushstring(L, "type"); lua_pushstring(L, pb->getType().c_str()); lua_rawset(L, -3);
    return 1;
}

#if NOT_USED_YET
/*
 * Race condition if we collect properties: if we add this property to
 * a TC and our life ends before that of the TC, the property will be
 * deleted before the TaskContext.
 */
static int Property_gc(lua_State *L)
{
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Property", PropertyBase));
    delete pb;
    return 0;
}
#endif

/* only explicit destruction allowed */
static int Property_del(lua_State *L)
{
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Property", PropertyBase));
    delete pb;

    /* this prevents calling rtt methods which would cause a crash */
    luaL_getmetatable(L, "__dead__");
    lua_setmetatable(L, -2);
    return 0;
}

/* indexability of properties */
/*
 * this is a dispatcher which checks if the key is a method, otherwise
 * calls get for looking up the field. Inspired by
 * http://lua-users.org/wiki/ObjectProperties
 */
static int Property_index(lua_State *L)
{
    const char* key = luaL_checkstring(L, 2);

    lua_getmetatable(L, 1);
    lua_getfield(L, -1, key); /* this actually calls the method */

    /* Either key is name of a method in the metatable */
    if(!lua_isnil(L, -1))
        return 1;

    lua_settop(L, 2);   /* reset stack */
    Property_get(L);    /* pushes property var */
    lua_replace(L, 1);  /* replace prop with var */
    return Variable_index(L);
}

static int Property_newindex(lua_State *L)
{
    Property_get(L);
    lua_replace(L, 1);
    return Variable_newindex(L);
}

static const struct luaL_Reg Property_f [] = {
    {"new", Property_new },
    {"get", Property_get },
    {"getRaw", Property_getRaw },
    {"set", Property_set },
    {"info", Property_info },
    {"delete", Property_del },
    {NULL, NULL}
};

static const struct luaL_Reg Property_m [] = {
    {"get", Property_get },
    {"getRaw", Property_getRaw },
    {"set", Property_set },
    {"info", Property_info },
    // todo: shall we or not? s.o. {"__gc", Property_gc },
    {"delete", Property_del },
    {"__index", Property_index },
    {"__newindex", Property_newindex },
    {NULL, NULL}
};

/***************************************************************
 * Attribute (boxed)
 ***************************************************************/

gen_push_bxptr(Attribute_push, "Attribute", AttributeBase)

static int Attribute_new(lua_State *L)
{
    const char *type, *name;
    AttributeBase *pb;
    int argc = lua_gettop(L);
    type = luaL_checkstring(L, 1);

    /* name and description are optional */
    name = (argc > 1) ? luaL_checkstring(L, 2) : "";

    types::TypeInfo *ti = types::TypeInfoRepository::Instance()->type(type);

    if(!ti)
        luaL_error(L, "Attribute.new: unknown type %s", type);

    pb =  ti->buildAttribute(name);
    Attribute_push(L, pb);
    return 1;
}

static int Attribute_get(lua_State *L)
{
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Attribute", AttributeBase));
    Variable_push_coerce(L, pb->getDataSource());
    return 1;
}

static int Attribute_getRaw(lua_State *L)
{
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Attribute", AttributeBase));
    luaM_pushobject_mt(L, "Variable", DataSourceBase::shared_ptr)(pb->getDataSource());
    return 1;
}

static int Attribute_set(lua_State *L)
{
    DataSourceBase::shared_ptr newdsb;
    DataSourceBase::shared_ptr *newdsbp;
    DataSourceBase::shared_ptr propdsb;
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Attribute", AttributeBase));
    propdsb = pb->getDataSource();

    /* assigning a DSB */
    if ((newdsbp = luaM_testudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)) != NULL) {
        newdsb = *newdsbp;
        if(!propdsb->update(newdsb.get()))
            luaL_error(L, "Attribute.set: failed to assign type %s to type %s",
                   newdsb->getType().c_str(), propdsb->getType().c_str());
    } else { /* assigning a Lua value */
        Variable_fromlua(L, propdsb, 2);
    }
    return 1;
}

static int Attribute_info(lua_State *L)
{
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Attribute", AttributeBase));
    lua_newtable(L);
    lua_pushstring(L, "name"); lua_pushstring(L, pb->getName().c_str()); lua_rawset(L, -3);
    lua_pushstring(L, "type"); lua_pushstring(L, pb->getDataSource()->getType().c_str()); lua_rawset(L, -3);
    return 1;
}

#if NOT_USED_YET
/*
 * Race condition if we collect properties: if we add this attribute to
 * a TC and our life ends before that of the TC, the attribute will be
 * deleted before the TaskContext.
 */
static int Attribute_gc(lua_State *L)
{
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Attribute", AttributeBase));
    delete pb;
    return 0;
}
#endif


/* only explicit destruction allowed */
static int Attribute_del(lua_State *L)
{
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 1, "Attribute", AttributeBase));
    delete pb;

    /* this prevents calling rtt methods which would cause a crash */
    luaL_getmetatable(L, "__dead__");
    lua_setmetatable(L, -2);
    return 0;
}

/* indexability of properties */
/*
 * this is a dispatcher which checks if the key is a method, otherwise
 * calls get for looking up the field. Inspired by
 * http://lua-users.org/wiki/ObjectProperties
 */
static int Attribute_index(lua_State *L)
{
    const char* key = luaL_checkstring(L, 2);

    lua_getmetatable(L, 1);
    lua_getfield(L, -1, key); /* this actually calls the method */

    /* Either key is name of a method in the metatable */
    if(!lua_isnil(L, -1))
        return 1;

    lua_settop(L, 2);   /* reset stack */
    Attribute_get(L);   /* pushes attribute var */
    lua_replace(L, 1);  /* replace prop with var */
    return Variable_index(L);
}

static int Attribute_newindex(lua_State *L)
{
    Attribute_get(L);
    lua_replace(L, 1);
    return Variable_newindex(L);
}

static const struct luaL_Reg Attribute_f [] = {
    {"new", Attribute_new },
    {"get", Attribute_get },
    {"getRaw", Attribute_getRaw },
    {"set", Attribute_set },
    {"info", Attribute_info },
    {"delete", Attribute_del },
    {NULL, NULL}
};

static const struct luaL_Reg Attribute_m [] = {
    {"get", Attribute_get },
    {"getRaw", Attribute_getRaw },
    {"set", Attribute_set },
    {"info", Attribute_info },
    // todo: shall we or not? s.o. {"__gc", Attribute_gc },
    {"delete", Attribute_del },
    {"__index", Attribute_index },
    {"__newindex", Attribute_newindex },
    {NULL, NULL}
};

/***************************************************************
 * Ports (boxed)
 ***************************************************************/

/* both input or output */
static int Port_info(lua_State *L)
{
    int arg_type;
    const char* port_type = NULL;
    PortInterface **pip;
    PortInterface *pi = NULL;

    if((pip = (PortInterface**) luaL_testudata(L, 1, "InputPort")) != NULL) {
        pi = *pip;
        port_type = "in";
    } else if((pip = (PortInterface**) luaL_testudata(L, 1, "OutputPort")) != NULL) {
        pi = *pip;
        port_type = "out";
    }
    else {
        arg_type = lua_type(L, 1);
        luaL_error(L, "Port.info: invalid argument, expected Port, got %s",
               lua_typename(L, arg_type));
    }

    lua_newtable(L);
    lua_pushstring(L, "name"); lua_pushstring(L, pi->getName().c_str()); lua_rawset(L, -3);
    lua_pushstring(L, "desc"); lua_pushstring(L, pi->getDescription().c_str()); lua_rawset(L, -3);
    lua_pushstring(L, "connected"); lua_pushboolean(L, pi->connected()); lua_rawset(L, -3);
    lua_pushstring(L, "isLocal"); lua_pushboolean(L, pi->isLocal()); lua_rawset(L, -3);
    lua_pushstring(L, "type"); lua_pushstring(L, pi->getTypeInfo()->getTypeName().c_str()); lua_rawset(L, -3);
    lua_pushstring(L, "porttype"); lua_pushstring(L, port_type); lua_rawset(L, -3);

    return 1;
}

static int Port_connect(lua_State *L)
{
    int arg_type, ret;
    PortInterface **pip1, **pip2;
    PortInterface *pi1 = NULL;
    PortInterface *pi2 = NULL;
    ConnPolicy **cpp;
    ConnPolicy *cp = NULL;

    if((pip1 = (PortInterface**) luaL_testudata(L, 1, "InputPort")) != NULL) {
        pi1= *pip1;
    } else if((pip1 = (PortInterface**) luaL_testudata(L, 1, "OutputPort")) != NULL) {
        pi1= *pip1;
    }
    else {
        arg_type = lua_type(L, 1);
        luaL_error(L, "Port.info: invalid argument 1, expected Port, got %s",
               lua_typename(L, arg_type));
    }
    if((pip2 = (PortInterface**) luaL_testudata(L, 2, "InputPort")) != NULL) {
        pi2= *pip2;
    } else if((pip2 = (PortInterface**) luaL_testudata(L, 2, "OutputPort")) != NULL) {
        pi2= *pip2;
    }
    else {
        arg_type = lua_type(L, 2);
        luaL_error(L, "Port.connect: invalid argument 2, expected Port, got %s",
               lua_typename(L, arg_type));
    }

    if((cpp = (ConnPolicy**) luaL_testudata(L, 3, "ConnPolicy")) != NULL) {
        cp=*cpp;
    }

    if ( cp )
        ret = pi1->connectTo(pi2, *cp);
    else
        ret = pi1->connectTo(pi2);

    lua_pushboolean(L, ret);

    return 1;
}

static int Port_disconnect(lua_State *L)
{
    int arg_type, ret;
    PortInterface **pip1, **pip2;
    PortInterface *pi1 = NULL;
    PortInterface *pi2 = NULL;

    if((pip1 = (PortInterface**) luaL_testudata(L, 1, "InputPort")) != NULL) {
        pi1= *pip1;
    } else if((pip1 = (PortInterface**) luaL_testudata(L, 1, "OutputPort")) != NULL) {
        pi1= *pip1;
    }
    else {
        arg_type = lua_type(L, 1);
        luaL_error(L, "Port.info: invalid argument 1, expected Port, got %s",
               lua_typename(L, arg_type));
    }
    if((pip2 = (PortInterface**) luaL_testudata(L, 2, "InputPort")) != NULL) {
    pi2= *pip2;
    } else if((pip2 = (PortInterface**) luaL_testudata(L, 2, "OutputPort")) != NULL) {
    pi2= *pip2;
    }

    if (pi2 != NULL)
    ret = pi1->disconnect(pi2);
    else{
    pi1->disconnect();
    ret = 1;
    }
    lua_pushboolean(L, ret);

    return 1;
}



/* InputPort (boxed) */

gen_push_bxptr(InputPort_push, "InputPort", InputPortInterface)

static int InputPort_new(lua_State *L)
{
    const char *type, *name, *desc;
    InputPortInterface* ipi;
    int argc = lua_gettop(L);

    type = luaL_checkstring(L, 1);

    /* name and description are optional */
    name = (argc > 1) ? luaL_checkstring(L, 2) : "";
    desc = (argc > 2) ? luaL_checkstring(L, 3) : "";

    types::TypeInfo *ti = types::TypeInfoRepository::Instance()->type(type);
    if(ti==0)
        luaL_error(L, "InputPort.new: unknown type %s", type);

    ipi = ti->inputPort(name);

    if(!ipi)
        luaL_error(L, "InputPort.new: creating port of type %s failed", type);

    ipi->doc(desc);
    InputPort_push(L, ipi);
    return 1;
}

static int InputPort_read(lua_State *L)
{
    int ret = 1;
    InputPortInterface *ip = *(luaM_checkudata_mt_bx(L, 1, "InputPort", InputPortInterface));
    DataSourceBase::shared_ptr dsb;
    DataSourceBase::shared_ptr *dsbp;
    FlowStatus fs;

    /* if we get don't get a DS to store the result, create one */
    if ((dsbp = luaM_testudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)) != NULL)
        dsb = *dsbp;
    else {
        dsb = ip->getTypeInfo()->buildValue();
        ret = 2;
    }

    fs = ip->read(dsb);

    if(fs == NoData) lua_pushstring(L, "NoData");
    else if (fs == NewData) lua_pushstring(L, "NewData");
    else if (fs == OldData) lua_pushstring(L, "OldData");
    else luaL_error(L, "InputPort.read: unknown FlowStatus returned");

    if(ret>1)
        Variable_push_coerce(L, dsb);

    return ret;
}

#ifdef NOT_USED_YET
static int InputPort_gc(lua_State *L)
{
    InputPortInterface *ip = *(luaM_checkudata_mt_bx(L, 1, "InputPort", InputPortInterface));
    delete ip;
    return 0;
}
#endif

/* only explicit destruction allowed */
static int InputPort_del(lua_State *L)
{
    InputPortInterface *ip = *(luaM_checkudata_mt_bx(L, 1, "InputPort", InputPortInterface));
    delete ip;

    /* this prevents calling rtt methods which would cause a crash */
    luaL_getmetatable(L, "__dead__");
    lua_setmetatable(L, -2);
    return 0;
}

static const struct luaL_Reg InputPort_f [] = {
    {"new", InputPort_new },
    {"read", InputPort_read },
    {"info", Port_info },
    {"connect", Port_connect },
    {"disconnect", Port_disconnect },
    {"delete", InputPort_del },
    {NULL, NULL}
};

static const struct luaL_Reg InputPort_m [] = {
    {"read", InputPort_read },
    {"info", Port_info },
    {"delete", InputPort_del },
    {"connect", Port_connect },
    {"disconnect", Port_disconnect },
    /* {"__gc", InputPort_gc }, */
    {NULL, NULL}
};

/* OutputPort */

gen_push_bxptr(OutputPort_push, "OutputPort", OutputPortInterface)


static int OutputPort_new(lua_State *L)
{
    const char *type, *name, *desc;
    OutputPortInterface* opi;
    int argc = lua_gettop(L);

    type = luaL_checkstring(L, 1);

    /* name and description are optional */
    name = (argc > 1) ? luaL_checkstring(L, 2) : "";
    desc = (argc > 2) ? luaL_checkstring(L, 3) : "";

    types::TypeInfo *ti = types::TypeInfoRepository::Instance()->type(type);

    if(ti==0)
        luaL_error(L, "OutputPort.new: unknown type %s", type);

    opi = ti->outputPort(name);

    if(!opi)
        luaL_error(L, "OutputPort.new: creating port of type %s failed", type);

    opi->doc(desc);
    OutputPort_push(L, opi);
    return 1;
}

static int OutputPort_write(lua_State *L)
{
    DataSourceBase::shared_ptr dsb;
    DataSourceBase::shared_ptr *dsbp;

    OutputPortInterface *op = *(luaM_checkudata_mt_bx(L, 1, "OutputPort", OutputPortInterface));

    /* fastpath: Variable argument */
    if ((dsbp = luaM_testudata_mt(L, 2, "Variable", DataSourceBase::shared_ptr)) != NULL) {
        dsb = *dsbp;
    } else  {
        /* slowpath: convert lua value to dsb */
        dsb = Variable_fromlua(L, op->getTypeInfo(), 2);
    }
    op->write(dsb);
    return 0;
}

#ifdef NOT_USED_YET
static int OutputPort_gc(lua_State *L)
{
    OutputPortInterface *op = *(luaM_checkudata_mt_bx(L, 1, "OutputPort", OutputPortInterface));
    delete op;
    return 0;
}
#endif

/* only explicit destruction allowed */
static int OutputPort_del(lua_State *L)
{
    OutputPortInterface *op = *(luaM_checkudata_mt_bx(L, 1, "OutputPort", OutputPortInterface));
    delete op;

    /* this prevents calling rtt methods which would cause a crash */
    luaL_getmetatable(L, "__dead__");
    lua_setmetatable(L, -2);
    return 0;
}

static const struct luaL_Reg OutputPort_f [] = {
    {"new", OutputPort_new },
    {"write", OutputPort_write },
    {"info", Port_info },
    {"connect", Port_connect },
    {"disconnect", Port_disconnect },
    {"delete", OutputPort_del },
    {NULL, NULL}
};

static const struct luaL_Reg OutputPort_m [] = {
    {"write", OutputPort_write },
    {"info", Port_info },
    {"connect", Port_connect },
    {"disconnect", Port_disconnect },
    {"delete", OutputPort_del },
    /* {"__gc", OutputPort_gc }, */
    {NULL, NULL}
};

/***************************************************************
 * Operation
 ***************************************************************/

struct OperationHandle {
    OperationInterfacePart *oip;
    OperationCallerC *occ;
    unsigned int arity;
    bool is_void;

    /* we need to store references to the dsb which we created
       on-the-fly, because the ReferenceDSB does not hold a
       shared_ptr, and hence these DSN might get destructed
       before/during the call
     */
    std::vector<base::DataSourceBase::shared_ptr> dsb_store;
    std::vector<internal::Reference*> args;
    base::DataSourceBase::shared_ptr call_dsb;
    base::DataSourceBase::shared_ptr ret_dsb;
};

template<typename T>
int OperationGC(lua_State* L)
{
    T* oh = (T*) lua_touserdata(L, 1);
    delete oh->occ;
    reinterpret_cast<T*>(lua_touserdata(L, 1))->~T();
    return 0;
}

static int Operation_info(lua_State *L)
{
    int i=1;
    std::vector<ArgumentDescription> args;
    OperationHandle *op = luaM_checkudata_mt(L, 1, "Operation", OperationHandle);

    lua_pushstring(L, op->oip->getName().c_str());      /* name */
    lua_pushstring(L, op->oip->description().c_str());  /* description */
    lua_pushstring(L, op->oip->resultType().c_str());   /* result type */
    lua_pushinteger(L, op->arity);              /* arity */

    args = op->oip->getArgumentList();

    lua_newtable(L);

    for (std::vector<ArgumentDescription>::iterator it = args.begin(); it != args.end(); it++) {
        lua_newtable(L);
        lua_pushstring(L, "name"); lua_pushstring(L, it->name.c_str()); lua_rawset(L, -3);
        lua_pushstring(L, "type"); lua_pushstring(L, it->type.c_str()); lua_rawset(L, -3);
        lua_pushstring(L, "desc"); lua_pushstring(L, it->description.c_str()); lua_rawset(L, -3);
        lua_rawseti(L, -2, i++);
    }
    return 5;
}

static int __Operation_call(lua_State *L)
{
    bool ret;
    DataSourceBase::shared_ptr dsb, *dsbp;

    OperationHandle *oh = luaM_checkudata_mt(L, 1, "Operation", OperationHandle);
    OperationInterfacePart *oip = oh->oip;
    unsigned int argc = lua_gettop(L);

    if(oh->arity != argc-1)
        luaL_error(L, "Operation.call: wrong number of args. expected %d, got %d", oh->arity, argc-1);

    /* update dsbs */
    for(unsigned int arg=2; arg<=argc; arg++) {
        /* fastpath: Variable argument */
        if ((dsbp = luaM_testudata_mt(L, arg, "Variable", DataSourceBase::shared_ptr)) != NULL) {
            dsb = *dsbp;
        } else {
            /* slowpath: convert lua value to dsb */
            dsb = Variable_fromlua(L, oip->getArgumentType(arg-1), arg);
            /* this dsb must outlive occ->call (see comment in
               OperationHandle def.): */
            oh->dsb_store.push_back(dsb);
        }
        if(!dsb->isAssignable())
            luaL_error(L, "Operation.call: argument %d is not assignable.", arg-1);

        ret = oh->args[arg-2]->setReference(dsb);
        if (!ret)
            luaL_error(L, "Operation_call: setReference failed, wrong type of argument?");
    }

    if(!oh->occ->call())
        luaL_error(L, "Operation.call: call failed.");

    oh->dsb_store.clear();

    if(!oh->is_void)
        Variable_push_coerce(L, oh->ret_dsb);
    else
        lua_pushnil(L);
    return 1;
}

static int __Operation_send(lua_State *L)
{
    DataSourceBase::shared_ptr dsb, *dsbp;

    OperationHandle *oh = luaM_checkudata_mt(L, 1, "Operation", OperationHandle);
    OperationInterfacePart *oip = oh->oip;
    unsigned int argc = lua_gettop(L);

    if(oh->arity != argc-1)
        luaL_error(L, "Operation.send: wrong number of args. expected %d, got %d", oh->arity, argc-1);

    /* update dsbs */
    for(unsigned int arg=2; arg<=argc; arg++) {
        /* fastpath: Variable argument */
        if ((dsbp = luaM_testudata_mt(L, arg, "Variable", DataSourceBase::shared_ptr)) != NULL) {
            dsb = *dsbp;
        } else {
            /* slowpath: convert lua value to dsb */
            dsb = Variable_fromlua(L, oip->getArgumentType(arg-1), arg);
            /* this dsb must outlive occ->call (see comment in
               OperationHandle def.): */
            oh->dsb_store.push_back(dsb);
        }
        oh->args[arg-2]->setReference(dsb);
    }

    luaM_pushobject_mt(L, "SendHandle", SendHandleC)(oh->occ->send());
    return 1;
}

static int Operation_call(lua_State *L)
{
    int ret;
    try {
        ret = __Operation_call(L);
    } catch(const std::exception &exc) {
        luaL_error(L, "Operation.call: caught exception '%s'", exc.what());
    } catch(...) {
        luaL_error(L, "Operation.call: caught unknown exception");
    }
    return ret;
}

static int Operation_send(lua_State *L)
{
    int ret;
    try {
        ret = __Operation_send(L);
    } catch(const std::exception &exc) {
        luaL_error(L, "Operation.send: caught exception '%s'", exc.what());
    } catch(...) {
        luaL_error(L, "Operation.send: caught unknown exception");
    }
    return ret;
}


static const struct luaL_Reg Operation_f [] = {
    { "info", Operation_info },
    { "call", Operation_call },
    { "send", Operation_send },
    { NULL, NULL }

};

static const struct luaL_Reg Operation_m [] = {
    { "info", Operation_info },
    { "send", Operation_send },
    { "__call", Operation_call },
    { "__gc", OperationGC<OperationHandle> },
    { NULL, NULL }
};

/***************************************************************
 * Service (boxed)
 ***************************************************************/

static int Service_getName(lua_State *L)
{
    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    lua_pushstring(L, srv->getName().c_str());
    return 1;
}

static int Service_doc(lua_State *L)
{
    int ret;
    const char* doc;
    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    if(lua_gettop(L) == 1) {
        lua_pushstring(L, srv->doc().c_str());
        ret = 1;
    } else {
        doc = luaL_checkstring(L, 2);
        srv->doc(doc);
        ret = 0;
    }

    return ret;
}

static int Service_getProviderNames(lua_State *L)
{
    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    push_vect_str(L, srv->getProviderNames());
    return 1;
}

static int Service_getOperationNames(lua_State *L)
{
    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    push_vect_str(L, srv->getOperationNames());
    return 1;
}


static int Service_hasOperation(lua_State *L)
{
    int ret;
    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    const char* op = luaL_checkstring(L, 2);
    ret = srv->hasOperation(op);
    lua_pushboolean(L, ret);
    return 1;
}

static int Service_getPortNames(lua_State *L)
{
    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    push_vect_str(L, srv->getPortNames());
    return 1;
}

static int Service_provides(lua_State *L)
{
    int ret, i, argc;
    const char* subsrv_str;
    Service::shared_ptr srv, subsrv;

    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    argc=lua_gettop(L);

    /* return "this" if no args given */
    if(argc == 1) {
        ret = 1;
        goto out;
    }

    for(i=2; i<=argc; i++) {
        subsrv_str = luaL_checkstring(L, i);
        subsrv = srv->getService(subsrv_str);
        if (subsrv == 0)
            luaL_error(L, "Service.provides: no subservice %s of service %s",
                       subsrv_str, srv->getName().c_str() );
        else
            luaM_pushobject_mt(L, "Service", Service::shared_ptr)(subsrv);
    }
    ret = argc - 1;

 out:
    return ret;
}

static int Service_getOperation(lua_State *L)
{
    const char *op_str;
    OperationInterfacePart *oip;
    Service::shared_ptr srv;
    DataSourceBase::shared_ptr dsb;
    const types::TypeInfo *ti;
    OperationHandle *oh;
    TaskContext *this_tc;

    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    op_str = luaL_checkstring(L, 2);
    oip = srv->getOperation(op_str);

    if(!oip)
        luaL_error(L, "Service_getOperation: service %s has no operation %s",
               srv->getName().c_str(), op_str);

    oh = (OperationHandle*) luaM_pushobject_mt(L, "Operation", OperationHandle)();
    oh->oip = oip;
    oh->arity = oip->arity();
    oh->args.reserve(oh->arity);
    this_tc = __getTC(L);

    oh->occ = new OperationCallerC(oip, op_str, this_tc->engine());

    /* create args
     * getArgumentType(0) is return value
     */
    for(unsigned int arg=1; arg <= oh->arity; arg++) {
        std::string type = oip->getArgumentType(arg)->getTypeName();
        ti = types::TypeInfoRepository::Instance()->type(type);
        if(!ti)
            luaL_error(L, "Operation.call: '%s', failed to locate TypeInfo for arg %d of type '%s'",
                   op_str, arg, type.c_str());

        dsb = ti->buildReference((void*) 0xdeadbeef);
        if(!dsb)
            luaL_error(L, "Operation.call: '%s', failed to build DSB for arg %d of type '%s'",
                   op_str, arg, type.c_str());

        oh->args.push_back(dynamic_cast<internal::Reference*>(dsb.get()));
        oh->occ->arg(dsb);
    }

    /* return value */
    if(oip->resultType() != "void"){
        ti = oip->getArgumentType(0); // 0 == return type
        if(!ti)
            luaL_error(L, "Operation.call: '%s', failed to locate TypeInfo for return value of type '%s'",
                   op_str, oip->resultType().c_str());
        oh->ret_dsb=ti->buildValue();
        if(!oh->ret_dsb)
            luaL_error(L, "Operation.call: '%s', failed to build DSB for return value of type '%s'",
                   op_str, oip->resultType().c_str());

        oh->occ->ret(oh->ret_dsb);
        oh->is_void=false;
    } else {
        oh->is_void=true;
    }

    if(!oh->occ->ready())
        luaL_error(L, "Service.getOperation: OperationCallerC not ready!");

    return 1;
}

static int Service_getPort(lua_State *L)
{
    const char* name;
    PortInterface *pi;
    InputPortInterface *ipi;
    OutputPortInterface *opi;

    Service::shared_ptr srv;

    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    name = luaL_checkstring(L, 2);

    pi = srv->getPort(name);
    if(!pi)
        luaL_error(L, "Service.getPort: service %s has no port %",
               srv->getName().c_str(), name);

    /* input or output? */
    if ((ipi = dynamic_cast<InputPortInterface *> (pi)) != NULL)
        InputPort_push(L, ipi);
    else if ((opi = dynamic_cast<OutputPortInterface *> (pi)) != NULL)
        OutputPort_push(L, opi);
    else
        luaL_error(L, "Service.getPort: unknown port type returned");

    return 1;
}

static int Service_getProperty(lua_State *L)
{
    const char *name;
    PropertyBase *prop;

    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    name = luaL_checkstring(L, 2);

    prop = srv->getProperty(name);

    if(!prop)
        luaL_error(L, "%s failed. No such property", __FILE__);

    Property_push(L, prop);
    return 1;
}

static int Service_getPropertyNames(lua_State *L)
{
    Service::shared_ptr srv;
    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    std::vector<std::string> plist = srv->properties()->list();
    push_vect_str(L, plist);
    return 1;
}

static int Service_getProperties(lua_State *L)
{
    Service::shared_ptr srv;
    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    vector<PropertyBase*> props = srv->properties()->getProperties();

    int key = 1;
    lua_createtable(L, props.size(), 0);
    for(vector<PropertyBase*>::iterator it = props.begin(); it != props.end(); ++it) {
        Property_push(L, *it);
        lua_rawseti(L, -2, key++);
    }

    return 1;
}

static int Service_getAttribute(lua_State *L)
{
    const char *name;
    AttributeBase *prop;

    Service::shared_ptr srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    name = luaL_checkstring(L, 2);

    prop = srv->getAttribute(name);

    if(!prop)
        luaL_error(L, "%s failed. No such Attribute", __FILE__);

    Attribute_push(L, prop);
    return 1;
}

static int Service_getAttributeNames(lua_State *L)
{
    Service::shared_ptr srv;
    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    std::vector<std::string> plist = srv->getAttributeNames();
    push_vect_str(L, plist);
    return 1;
}

static int Service_getAttributes(lua_State *L)
{
    Service::shared_ptr srv;
    srv = *(luaM_checkudata_mt(L, 1, "Service", Service::shared_ptr));
    vector<AttributeBase*> props = srv->getValues();

    int key = 1;
    lua_createtable(L, props.size(), 0);
    for(vector<AttributeBase*>::iterator it = props.begin(); it != props.end(); ++it) {
        Attribute_push(L, *it);
        lua_rawseti(L, -2, key++);
    }

    return 1;
}

static const struct luaL_Reg Service_f [] = {
    { "getName", Service_getName },
    { "doc", Service_doc },
    { "getProviderNames", Service_getProviderNames },
    { "getOperationNames", Service_getOperationNames },
    { "hasOperation", Service_hasOperation },
    { "getPortNames", Service_getPortNames },
    { "provides", Service_provides },
    { "getOperation", Service_getOperation },
    { "getPort", Service_getPort },
    { "getProperty", Service_getProperty },
    { "getProperties", Service_getProperties },
    { "getPropertyNames", Service_getPropertyNames },
    { "getAttribute", Service_getAttribute },
    { "getAttributes", Service_getAttributes },
    { "getAttributeNames", Service_getAttributeNames },
    { NULL, NULL }
};

static const struct luaL_Reg Service_m [] = {
    { "getName", Service_getName },
    { "doc", Service_doc },
    { "getProviderNames", Service_getProviderNames },
    { "getOperationNames", Service_getOperationNames },
    { "hasOperation", Service_hasOperation },
    { "getPortNames", Service_getPortNames },
    { "provides", Service_provides },
    { "getOperation", Service_getOperation },
    { "getPort", Service_getPort },
    { "getProperty", Service_getProperty },
    { "getProperties", Service_getProperties },
    { "getPropertyNames", Service_getPropertyNames },
    { "getAttribute", Service_getAttribute },
    { "getAttributes", Service_getAttributes },
    { "getAttributeNames", Service_getAttributeNames },
    { "__gc", GCMethod<Service::shared_ptr> },
    { NULL, NULL }
};

/***************************************************************
 * ServiceRequester
 ***************************************************************/

gen_push_bxptr(ServiceRequester_push, "ServiceRequester", ServiceRequester)

static int ServiceRequester_getRequestName(lua_State *L)
{
    ServiceRequester *sr;

    sr = *(luaM_checkudata_bx(L, 1, ServiceRequester));
    lua_pushstring(L, sr->getRequestName().c_str());
    return 1;
}

static int ServiceRequester_getRequesterNames(lua_State *L)
{
    ServiceRequester *sr;
    sr = *(luaM_checkudata_bx(L, 1, ServiceRequester));
    push_vect_str(L, sr->getRequesterNames());
    return 1;
}

static int ServiceRequester_ready(lua_State *L)
{
    int ret;
    ServiceRequester *sr;
    sr = *(luaM_checkudata_bx(L, 1, ServiceRequester));
    ret = sr->ready();
    lua_pushboolean(L, ret);
    return 1;
}

static int ServiceRequester_disconnect(lua_State *L)
{
    ServiceRequester *sr;
    sr = *(luaM_checkudata_bx(L, 1, ServiceRequester));
    sr->disconnect();
    return 0;
}

static int ServiceRequester_requires(lua_State *L)
{
    int argc, ret, i;
    const char* subsr_str;
    ServiceRequester *sr;
    ServiceRequester::shared_ptr subsr;

    sr = *(luaM_checkudata_bx(L, 1, ServiceRequester));
    argc = lua_gettop(L);

    /* return "this" if no args given */
    if(argc == 1) {
        ret = 1;
        goto out;
    }

    for(i=2; i<=argc; i++) {
        subsr_str = luaL_checkstring(L, i);
        subsr = sr->requires(subsr_str);
        if (subsr == 0)
            luaL_error(L, "ServiceRequester: no required subservice %s of service %s",
                   subsr_str, sr->getRequestName().c_str());
        else
            ServiceRequester_push(L, subsr.get());
    }
    ret = argc - 1;

 out:
    return ret;
}

static const struct luaL_Reg ServiceRequester_f [] = {
    { "getRequestName", ServiceRequester_getRequestName },
    { "getRequesterNames", ServiceRequester_getRequesterNames },
    { "ready", ServiceRequester_ready },
    { "disconnect", ServiceRequester_disconnect },
    { "requires", ServiceRequester_requires },
    { NULL, NULL }
};

static const struct luaL_Reg ServiceRequester_m [] = {
    { "getRequestName", ServiceRequester_getRequestName },
    { "getRequesterNames", ServiceRequester_getRequesterNames },
    { "ready", ServiceRequester_ready },
    { "disconnect", ServiceRequester_disconnect },
    { "requires", ServiceRequester_requires },
    { NULL, NULL }
};


/***************************************************************
 * TaskContext (boxed)
 ***************************************************************/

gen_push_bxptr(TaskContext_push, "TaskContext", TaskContext)

static int TaskContext_getName(lua_State *L)
{
    const char *s;
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    s = tc->getName().c_str();
    lua_pushstring(L, s);
    return 1;
}

static int TaskContext_start(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    bool b = tc->start();
    lua_pushboolean(L, b);
    return 1;
}

static int TaskContext_stop(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    bool b = tc->stop();
    lua_pushboolean(L, b);
    return 1;
}

static int TaskContext_configure(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    bool ret = tc->configure();
    lua_pushboolean(L, ret);
    return 1;
}

static int TaskContext_activate(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    bool ret = tc->activate();
    lua_pushboolean(L, ret);
    return 1;
}

static int TaskContext_cleanup(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    bool ret = tc->cleanup();
    lua_pushboolean(L, ret);
    return 1;
}

static int TaskContext_error(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    tc->error();
    return 0;
}

static int TaskContext_recover(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    bool ret = tc->recover();
    lua_pushboolean(L, ret);
    return 1;
}

static int TaskContext_getState(lua_State *L)
{
    TaskCore::TaskState ts;
    TaskContext **tc = (TaskContext**) luaM_checkudata_bx(L, 1, TaskContext);
    ts = (*tc)->getTaskState();

    switch(ts) {
    case TaskCore::Init:        lua_pushstring(L, "Init"); break;
    case TaskCore::PreOperational:  lua_pushstring(L, "PreOperational"); break;
    case TaskCore::FatalError:  lua_pushstring(L, "FatalError"); break;
    case TaskCore::Exception:   lua_pushstring(L, "Exception"); break;
    case TaskCore::Stopped:     lua_pushstring(L, "Stopped"); break;
    case TaskCore::Running:     lua_pushstring(L, "Running"); break;
    case TaskCore::RunTimeError:    lua_pushstring(L, "RunTimeError"); break;
    default:            lua_pushstring(L, "unknown");
    }
    return 1;
}

/* string-table getPeers(TaskContext self)*/
/* should better return array of TC's */
static int TaskContext_getPeers(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    std::vector<std::string> plist = tc->getPeerList();
    push_vect_str(L, plist);
    return 1;
}

/* bool addPeer(TaskContext self, TaskContext peer)*/
static int TaskContext_addPeer(lua_State *L)
{
    bool ret;
    TaskContext *self = *(luaM_checkudata_bx(L, 1, TaskContext));
    TaskContext *peer = *(luaM_checkudata_bx(L, 2, TaskContext));
    ret = self->addPeer(peer);
    lua_pushboolean(L, ret);
    return 1;
}

/* bool connectPeers(TaskContext self, TaskContext peer)*/
static int TaskContext_connectPeers(lua_State *L)
{
    bool ret;
    TaskContext *self = *(luaM_checkudata_bx(L, 1, TaskContext));
    TaskContext *peer = *(luaM_checkudata_bx(L, 2, TaskContext));
    ret = self->connectPeers(peer);
    lua_pushboolean(L, ret);
    return 1;
}

/* void removePeer(TaskContext self, string peer)*/
static int TaskContext_removePeer(lua_State *L)
{
    std::string peer;
    TaskContext *self = *(luaM_checkudata_bx(L, 1, TaskContext));
    peer = luaL_checkstring(L, 2);
    self->removePeer(peer);
    return 0;
}

/* TaskContext getPeer(string name) */
static int TaskContext_getPeer(lua_State *L)
{
    std::string strpeer;
    TaskContext *peer;
    TaskContext *self = *(luaM_checkudata_bx(L, 1, TaskContext));
    strpeer = luaL_checkstring(L, 2);
    peer = self->getPeer(strpeer);

    if(!peer) {
        luaL_error(L, "TaskContext.getPeer: no peer %s", strpeer.c_str());
        goto out;
    }

    TaskContext_push(L, peer);
 out:
    return 1;
}

static int TaskContext_getPortNames(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    std::vector<std::string> plist = tc->ports()->getPortNames();
    push_vect_str(L, plist);
    return 1;
}

static int TaskContext_addPort(lua_State *L)
{
    const char* name, *desc;
    PortInterface **pi;
    int argc = lua_gettop(L);
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));

    pi = (PortInterface**) luaL_testudata(L, 2, "InputPort");
    if(pi) goto check_name;

    pi = (PortInterface**) luaL_testudata(L, 2, "OutputPort");
    if(pi) goto check_name;

    return luaL_error(L, "addPort: invalid argument, not a Port");

 check_name:
    if(argc > 2) {
        name = luaL_checkstring(L, 3);
        (*pi)->setName(name);
    }

    if(argc > 3) {
        desc = luaL_checkstring(L, 4);
        (*pi)->doc(desc);
    }

    tc->ports()->addPort(**pi);
    return 0;
}

static int TaskContext_addEventPort(lua_State *L)
{
    const char* name, *desc;
    InputPortInterface **ipi;
    int argc = lua_gettop(L);
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));

    if((ipi = (InputPortInterface**) luaL_testudata(L, 2, "InputPort")) == NULL)
        return luaL_error(L, "addEventPort: invalid argument, not an InputPort");

    if(argc > 2) {
        name = luaL_checkstring(L, 3);
        (*ipi)->setName(name);
    }

    if(argc > 3) {
        desc = luaL_checkstring(L, 4);
        (*ipi)->doc(desc);
    }

    tc->ports()->addEventPort(**ipi);
    return 0;
}

static int TaskContext_getPort(lua_State *L)
{
    const char* name;
    PortInterface *pi;
    InputPortInterface *ipi;
    OutputPortInterface *opi;

    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    name = luaL_checkstring(L, 2);

    pi = tc->getPort(name);
    if(!pi)
        luaL_error(L, "TaskContext.getPort: no port %s for taskcontext %s",
               name, tc->getName().c_str());

    /* input or output? */
    if ((ipi = dynamic_cast<InputPortInterface *> (pi)) != NULL)
        InputPort_push(L, ipi);
    else if ((opi = dynamic_cast<OutputPortInterface *> (pi)) != NULL)
        OutputPort_push(L, opi);
    else
        luaL_error(L, "TaskContext.getPort: unknown port returned");

    return 1;
}

static int TaskContext_removePort(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    const char *port = luaL_checkstring(L, 2);
    tc->ports()->removePort(port);
    return 0;
}

static int TaskContext_addProperty(lua_State *L)
{
    const char *name, *desc;
    int argc = lua_gettop(L);
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    PropertyBase *pb = *(luaM_checkudata_mt_bx(L, 2, "Property", PropertyBase));

    if(argc > 2) {
        name = luaL_checkstring(L, 3);
        pb->setName(name);
    }

    if(argc > 3) {
        desc = luaL_checkstring(L, 4);
        pb->setDescription(desc);
    }


    if(!tc->addProperty(*pb))
        luaL_error(L, "TaskContext.addProperty: failed to add property %s.",
               pb->getName().c_str());

    return 0;
}

static int TaskContext_getProperty(lua_State *L)
{
    const char *name;
    PropertyBase *prop;

    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    name = luaL_checkstring(L, 2);

    prop = tc->getProperty(name);

    if(!prop)
        luaL_error(L, "%s failed. No such property", __FILE__);

    Property_push(L, prop);
    return 1;
}


static int TaskContext_getPropertyNames(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    std::vector<std::string> plist = tc->properties()->list();
    push_vect_str(L, plist);
    return 1;
}

static int TaskContext_getProperties(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    vector<PropertyBase*> props = tc->properties()->getProperties();

    int key = 1;
    lua_createtable(L, props.size(), 0);
    for(vector<PropertyBase*>::iterator it = props.begin(); it != props.end(); ++it) {
        Property_push(L, *it);
        lua_rawseti(L, -2, key++);
    }

    return 1;
}

static int TaskContext_removeProperty(lua_State *L)
{
    const char *name;
    PropertyBase *prop;

    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    name = luaL_checkstring(L, 2);

    prop = tc->getProperty(name);

    if(!prop)
        luaL_error(L, "%s failed. No such property", __FILE__);

    tc->properties()->remove(prop);
    return 0;
}

static int TaskContext_addAttribute(lua_State *L)
{
    int argc = lua_gettop(L);
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    AttributeBase *pb = *(luaM_checkudata_mt_bx(L, 2, "Attribute", AttributeBase));

    if(argc > 2) {
        const char *name = luaL_checkstring(L, 3);
        pb->setName(name);
    }

    if(!tc->addAttribute(*pb))
        luaL_error(L, "TaskContext.addAttribute: failed to add attribute %s.",
               pb->getName().c_str());

    return 0;
}

static int TaskContext_getAttribute(lua_State *L)
{
    const char *name;
    AttributeBase *prop;

    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    name = luaL_checkstring(L, 2);

    prop = tc->getAttribute(name);

    if(!prop)
        luaL_error(L, "%s failed. No such Attribute", __FILE__);

    Attribute_push(L, prop);
    return 1;
}


static int TaskContext_getAttributeNames(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    std::vector<std::string> plist = tc->attributes()->getAttributeNames();
    push_vect_str(L, plist);
    return 1;
}

static int TaskContext_getAttributes(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    vector<AttributeBase*> props = tc->attributes()->getValues();

    int key = 1;
    lua_createtable(L, props.size(), 0);
    for(vector<AttributeBase*>::iterator it = props.begin(); it != props.end(); ++it) {
        Attribute_push(L, *it);
        lua_rawseti(L, -2, key++);
    }

    return 1;
}

static int TaskContext_removeAttribute(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    const char *name = luaL_checkstring(L, 2);

    if(!tc->attributes()->hasAttribute(name))
        luaL_error(L, "%s failed. No such attribute", __FILE__);

    tc->attributes()->removeAttribute(name);

    return 0;
}

static int TaskContext_getOps(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    std::vector<std::string> oplst = tc->operations()->getNames();
    push_vect_str(L, oplst);
    return 1;
}

/* returns restype, arity, table-of-arg-descr */
static int TaskContext_getOpInfo(lua_State *L)
{
    int i=1;
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    const char *op = luaL_checkstring(L, 2);
    std::vector<ArgumentDescription> args;

    if(!tc->operations()->hasMember(op))
        luaL_error(L, "TaskContext.getOpInfo failed: no such operation");

    lua_pushstring(L, tc->operations()->getResultType(op).c_str()); /* result type */
    lua_pushinteger(L, tc->operations()->getArity(op));     /* arity */
    lua_pushstring(L, tc->operations()->getDescription(op).c_str()); /* description */

    args = tc->operations()->getArgumentList(op);

    lua_newtable(L);

    for (std::vector<ArgumentDescription>::iterator it = args.begin(); it != args.end(); it++) {
        lua_newtable(L);
        lua_pushstring(L, "name"); lua_pushstring(L, it->name.c_str()); lua_rawset(L, -3);
        lua_pushstring(L, "type"); lua_pushstring(L, it->type.c_str()); lua_rawset(L, -3);
        lua_pushstring(L, "desc"); lua_pushstring(L, it->description.c_str()); lua_rawset(L, -3);
        lua_rawseti(L, -2, i++);
    }

    return 4;
}

static int TaskContext_provides(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    Service::shared_ptr srv = tc->provides();

    if(srv == 0)
        luaL_error(L, "TaskContext.provides: no default service");

    /* forward to Serivce.provides */
    luaM_pushobject_mt(L, "Service", Service::shared_ptr)(srv);
    lua_replace(L, 1);
    return Service_provides(L);
}

static int TaskContext_getProviderNames(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    Service::shared_ptr srv = tc->provides();
    push_vect_str(L, srv->getProviderNames());
    return 1;
}

static int TaskContext_requires(lua_State *L)
{
    ServiceRequester::shared_ptr sr;
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    sr = tc->requires();

    if(!sr)
        luaL_error(L, "TaskContext.requires returned NULL");

    ServiceRequester_push(L, sr.get());
    lua_replace(L, 1);
    return ServiceRequester_requires(L);
}

static int TaskContext_connectServices(lua_State *L)
{
    int ret;
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    TaskContext *peer = *(luaM_checkudata_bx(L, 2, TaskContext));
    ret = tc->connectServices(peer);
    lua_pushboolean(L, ret);
    return 1;
}

static int TaskContext_hasOperation(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    Service::shared_ptr srv = tc->provides();

    if(srv == 0)
        luaL_error(L, "TaskContext.provides: no default service");

    /* forward to Serivce.hasOperation */
    luaM_pushobject_mt(L, "Service", Service::shared_ptr)(srv);
    lua_replace(L, 1);
    return Service_hasOperation(L);
}


static int TaskContext_getOperation(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    Service::shared_ptr srv = tc->provides();

    if(srv == 0)
        luaL_error(L, "TaskContext.getOperation: no default service");

    /* forward to Serivce.getOperation */
    luaM_pushobject_mt(L, "Service", Service::shared_ptr)(srv);
    lua_replace(L, 1);
    return Service_getOperation(L);
}

/*
 * SendHandle (required for send)
 */

static void SendStatus_push(lua_State *L, SendStatus ss)
{
    switch (ss) {
    case SendSuccess:  lua_pushstring(L, "SendSuccess"); break;
    case SendNotReady: lua_pushstring(L, "SendNotReady"); break;
    case SendFailure:  lua_pushstring(L, "SendFailure"); break;
    default:       lua_pushstring(L, "unkown");
    }
}

static int __SendHandle_collect(lua_State *L, bool block)
{
    unsigned int coll_argc;
    std::vector<DataSourceBase::shared_ptr> coll_args; /* temporarily store args */
    SendStatus ss;
    const types::TypeInfo *ti;
    OperationInterfacePart *oip;
    DataSourceBase::shared_ptr dsb, *dsbp;

    unsigned int argc = lua_gettop(L);
    SendHandleC *shc = luaM_checkudata_mt(L, 1, "SendHandle", SendHandleC);

    /* get orp pointer */
    oip = shc->getOrp();
    coll_argc = oip->collectArity();

    if(block && (argc == 1)) {
        // No args supplied, create them.
        for(unsigned int i=1; i<=coll_argc; i++) {
            ti = oip->getCollectType(i);
            dsb = ti->buildValue();
            coll_args.push_back(dsb);
            shc->arg(dsb);
        }
    } else if (argc-1 == coll_argc) {
        // args supplied, use them.
        if (!shc->ready()) {
            for(unsigned int arg=2; arg<=argc; arg++) {
                if ((dsbp = luaM_testudata_mt(L, arg, "Variable", DataSourceBase::shared_ptr)) != NULL)
                    dsb = *dsbp;
                else
                    luaL_error(L, "SendHandle.collect: expected Variable argument at position %d", arg-1);
                shc->arg(dsb);
            }
        }
    } else {
        if (block) {
            luaL_error(L, "SendHandle.collect: wrong number of args. expected either 0 or %d, got %d",
                   coll_argc, argc-1);
        } else {
            luaL_error(L, "SendHandle.collectIfDone: wrong number of args. expected %d, got %d",
                   coll_argc, argc-1);
        }
    }

    if(block) ss = shc->collect();
    else ss = shc->collectIfDone();

    SendStatus_push(L, ss);

    if(ss == SendSuccess) {
        for (unsigned int i=0; i<coll_args.size(); i++)
            Variable_push_coerce(L, coll_args[i]);

        /* SendStatus + collect args */
        return coll_args.size() + 1;

    } else {
        /* SendStatus only */
        return 1;
    }
}

static int SendHandle_collect(lua_State *L) { return __SendHandle_collect(L, true); }
static int SendHandle_collectIfDone(lua_State *L) { return __SendHandle_collect(L, false); }

static const struct luaL_Reg SendHandle_f [] = {
    { "collect", SendHandle_collect },
    { "collectIfDone", SendHandle_collectIfDone },
    { NULL, NULL }
};

static const struct luaL_Reg SendHandle_m [] = {
    { "collect", SendHandle_collect },
    { "collectIfDone", SendHandle_collectIfDone },
    { "__gc", GCMethod<SendHandleC> },
    { NULL, NULL }
};

/* only explicit destruction allowed */
static int TaskContext_del(lua_State *L)
{
    TaskContext *tc = *(luaM_checkudata_bx(L, 1, TaskContext));
    delete tc;

    /* this prevents calling rtt methods which would cause a crash */
    luaL_getmetatable(L, "__dead__");
    lua_setmetatable(L, -2);
    return 0;
}

static const struct luaL_Reg TaskContext_f [] = {
    { "getName", TaskContext_getName },
    { "start", TaskContext_start },
    { "stop", TaskContext_stop },
    { "configure", TaskContext_configure },
    { "activate", TaskContext_activate },
    { "cleanup", TaskContext_cleanup },
    { "error", TaskContext_error },
    { "recover", TaskContext_recover },
    { "getState", TaskContext_getState },
    { "getPeers", TaskContext_getPeers },
    { "addPeer", TaskContext_addPeer },
    { "removePeer", TaskContext_removePeer },
    { "getPeer", TaskContext_getPeer },
    { "getPortNames", TaskContext_getPortNames },
    { "addPort", TaskContext_addPort },
    { "addEventPort", TaskContext_addEventPort },
    { "getPort", TaskContext_getPort },
    { "removePort", TaskContext_removePort },
    { "addProperty", TaskContext_addProperty },
    { "getProperty", TaskContext_getProperty },
    { "getProperties", TaskContext_getProperties },
    { "getPropertyNames", TaskContext_getPropertyNames },
    { "removeProperty", TaskContext_removeProperty },
    { "addAttribute", TaskContext_addAttribute },
    { "getAttribute", TaskContext_getAttribute },
    { "getAttributes", TaskContext_getAttributes },
    { "getAttributeNames", TaskContext_getAttributeNames },
    { "removeAttribute", TaskContext_removeAttribute },
    { "getOps", TaskContext_getOps },
    { "getOpInfo", TaskContext_getOpInfo },
    { "hasOperation", TaskContext_hasOperation },
    { "provides", TaskContext_provides },
    { "getProviderNames", TaskContext_getProviderNames },
    { "connectServices", TaskContext_connectServices },
    { "getOperation", TaskContext_getOperation },
    { "delete", TaskContext_del },
    { NULL, NULL}
};

static const struct luaL_Reg TaskContext_m [] = {
    { "getName", TaskContext_getName },
    { "start", TaskContext_start },
    { "stop", TaskContext_stop },
    { "configure", TaskContext_configure },
    { "activate", TaskContext_activate },
    { "cleanup", TaskContext_cleanup },
    { "error", TaskContext_error },
    { "recover", TaskContext_recover },
    { "getState", TaskContext_getState },
    { "getPeers", TaskContext_getPeers },
    { "addPeer", TaskContext_addPeer },
    { "connectPeers", TaskContext_connectPeers },
    { "removePeer", TaskContext_removePeer },
    { "getPeer", TaskContext_getPeer },
    { "getPortNames", TaskContext_getPortNames },
    { "addPort", TaskContext_addPort },
    { "addEventPort", TaskContext_addEventPort },
    { "getPort", TaskContext_getPort },
    { "removePort", TaskContext_removePort },
    { "addProperty", TaskContext_addProperty },
    { "getProperty", TaskContext_getProperty },
    { "getProperties", TaskContext_getProperties },
    { "getPropertyNames", TaskContext_getPropertyNames },
    { "addAttribute", TaskContext_addAttribute },
    { "getAttribute", TaskContext_getAttribute },
    { "getAttributes", TaskContext_getAttributes },
    { "getAttributeNames", TaskContext_getAttributeNames },
    { "removeAttribute", TaskContext_removeAttribute },
    { "removeProperty", TaskContext_removeProperty },
    { "getOps", TaskContext_getOps },
    { "getOpInfo", TaskContext_getOpInfo },
    { "hasOperation", TaskContext_hasOperation },
    { "provides", TaskContext_provides },
    { "getProviderNames", TaskContext_getProviderNames },
    { "requires", TaskContext_requires },
    { "connectServices", TaskContext_connectServices },
    { "getOperation", TaskContext_getOperation },
    { "delete", TaskContext_del },
    // { "__index", TaskContext_index },
    /* we don't GC TaskContexts
     * { "__gc", GCMethod<TaskContext> }, */
    { NULL, NULL}
};

/*
 * Execution engine hook registration
 */

/* executable IF */
class EEHook : public base::ExecutableInterface
{
protected:
    std::string func;
    lua_State *L;
    TaskContext *tc; /* remember this to be able to print TC name
                in error messages */
public:
    EEHook(lua_State *_L, std::string _func) { L = _L; func = _func; tc = __getTC(L); }
    bool execute() { return call_func(L, func.c_str(), tc, 1, 1); }
};

static int EEHook_new(lua_State *L)
{
    const char *func;
    func = luaL_checkstring(L, 1);
    luaM_pushobject(L, EEHook)(L, func);
    return 1;
}

static int EEHook_enable(lua_State *L)
{
    EEHook *eeh = luaM_checkudata(L, 1, EEHook);
    TaskContext *tc = __getTC(L);
    lua_pushboolean(L, tc->engine()->runFunction(eeh));
    return 1;
}

static int EEHook_disable(lua_State *L)
{   EEHook *eeh = luaM_checkudata(L, 1, EEHook);
    TaskContext *tc = __getTC(L);
    lua_pushboolean(L, tc->engine()->removeFunction(eeh));
    return 1;
}

#if 0
static int EEHook_gc(lua_State *L)
{
    EEHook_disable(L);
    lua_settop(L, 1);
    reinterpret_cast<EEHook*>(lua_touserdata(L, 1))->~EEHook();
    return 0;
}
#endif

static const struct luaL_Reg EEHook_f [] = {
    { "new", EEHook_new },
    { "enable", EEHook_enable },
    { "disable", EEHook_disable },
};


static const struct luaL_Reg EEHook_m [] = {
    { "enable", EEHook_enable },
    { "disable", EEHook_disable },
    /* { "__gc", EEHook_gc }, */
};


/*
 * Logger and miscellaneous
 */
static const char *const loglevels[] = {
    "Never", "Fatal", "Critical", "Error", "Warning", "Info", "Debug", "RealTime", NULL
};

static int Logger_setLogLevel(lua_State *L)
{
    Logger::LogLevel ll = (Logger::LogLevel) luaL_checkoption(L, 1, NULL, loglevels);
    log().setLogLevel(ll);
    return 0;
}

static int Logger_getLogLevel(lua_State *L)
{
    Logger::LogLevel ll = log().getLogLevel();

    switch(ll) {
    case Logger::Never: lua_pushstring(L, "Never"); break;
    case Logger::Fatal: lua_pushstring(L, "Fatal"); break;
    case Logger::Critical:  lua_pushstring(L, "Critical"); break;
    case Logger::Error: lua_pushstring(L, "Error"); break;
    case Logger::Warning:   lua_pushstring(L, "Warning"); break;
    case Logger::Info:  lua_pushstring(L, "Info"); break;
    case Logger::Debug: lua_pushstring(L, "Debug"); break;
    case Logger::RealTime:  lua_pushstring(L, "RealTime"); break;
    default:
        lua_pushstring(L, "unknown");
    }
    return 1;
}

static int Logger_log(lua_State *L)
{
    const char *mes;
    for(int i=1; i<=lua_gettop(L); i++) {
        mes = luaL_checkstring(L, i);
        Logger::log() << mes;
    }
    Logger::log() << endlog();
    return 0;
}

static int Logger_logl(lua_State *L)
{
    const char *mes;
    Logger::LogLevel ll = (Logger::LogLevel) luaL_checkoption(L, 1, NULL, loglevels);
    for(int i=2; i<=lua_gettop(L); i++) {
        mes = luaL_checkstring(L, i);
        Logger::log(ll) << mes;
    }
    Logger::log(ll) << endlog();
    return 0;
}

/* misc stuff */

static int getTime(lua_State *L)
{
    unsigned long nsec, sec;
    RTT::os::TimeService::nsecs total_nsec = TimeService::Instance()->getNSecs();
    sec =  total_nsec / 1000000000;
    nsec = total_nsec % 1000000000;
    lua_pushinteger(L, sec);
    lua_pushinteger(L, nsec);
    return 2;
}

static int rtt_sleep(lua_State *L)
{
    TIME_SPEC ts;
    ts.tv_sec = luaL_checknumber(L, 1);
    ts.tv_nsec = luaL_checknumber(L, 2);
    rtos_nanosleep(&ts, NULL);
    return 0;
}

static int getTC(lua_State *L)
{
    lua_pushstring(L, "this_TC");
    lua_rawget(L, LUA_REGISTRYINDEX);
    return 1;
}

static TaskContext* __getTC(lua_State *L)
{
    TaskContext *tc;
    getTC(L);
    tc = *(luaM_checkudata_bx(L, -1, TaskContext));
    lua_pop(L, 1);
    return tc;
}

/* access to the globals repository */
static int globals_getNames(lua_State *L)
{
    GlobalsRepository::shared_ptr gr = GlobalsRepository::Instance();
    push_vect_str(L, gr->getAttributeNames() );
    return 1;
}

static int globals_get(lua_State *L)
{
    const char *name;
    base::AttributeBase *ab;
    DataSourceBase::shared_ptr dsb;

    name = luaL_checkstring(L, 1);
    GlobalsRepository::shared_ptr gr = GlobalsRepository::Instance();

    ab = gr->getAttribute(name);

    if (ab)
        Variable_push_coerce(L, ab->getDataSource());
    else
        lua_pushnil(L);

    return 1;
}

/* global service */
static int provides_global(lua_State *L)
{
    luaM_pushobject_mt(L, "Service", Service::shared_ptr)(GlobalService::Instance());
    lua_insert(L, 1);
    return Service_provides(L);
}

static int rtt_services(lua_State *L)
{
    push_vect_str(L, PluginLoader::Instance()->listServices());
    return 1;
}

static int rtt_typekits(lua_State *L)
{
    push_vect_str(L, PluginLoader::Instance()->listTypekits());
    return 1;
}

static int rtt_types(lua_State *L)
{
    push_vect_str(L, TypeInfoRepository::Instance()->getTypes());
    return 1;
}

static const struct luaL_Reg rtt_f [] = {
    {"getTime", getTime },
    {"sleep", rtt_sleep },
    {"getTC", getTC },
    {"globals_getNames", globals_getNames },
    {"globals_get", globals_get },
    {"provides", provides_global },
    {"services", rtt_services },
    {"typekits", rtt_typekits },
    {"types", rtt_types },
    {"setLogLevel", Logger_setLogLevel },
    {"getLogLevel", Logger_getLogLevel },
    {"log", Logger_log },
    {"logl", Logger_logl },
    {NULL, NULL}
};

extern "C" int luaopen_rtt(lua_State *L);

int luaopen_rtt(lua_State *L)
{
    lua_newtable(L);
    lua_replace(L, LUA_ENVIRONINDEX);

    luaL_newmetatable(L, "__dead__");

    /* register MyObj
     * 1. line creates metatable MyObj and registers name in registry
     * 2. line duplicates metatable
     * 3. line sets metatable[__index]=metatable
     *    (more precisely: table at -2 [__index] = top_of_stack, pops top of stack)
     * 4. line register methods in metatable
     * 5. line registers free functions in global mystuff.MyObj table
     */
    luaL_newmetatable(L, "TaskContext");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, TaskContext_m);
    luaL_register(L, "rtt.TaskContext", TaskContext_f);

    luaL_newmetatable(L, "Operation");
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, Operation_m);
    luaL_register(L, "rtt.Operation", Operation_f);

    luaL_newmetatable(L, "Service");
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, Service_m);
    luaL_register(L, "rtt.Service", Service_f);

    luaL_newmetatable(L, "ServiceRequester");
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, ServiceRequester_m);
    luaL_register(L, "rtt.ServiceRequester", ServiceRequester_f);

    luaL_newmetatable(L, "SendHandle");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, SendHandle_m);
    luaL_register(L, "rtt.SendHandle", SendHandle_f);

    luaL_newmetatable(L, "InputPort");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, InputPort_m);
    luaL_register(L, "rtt.InputPort", InputPort_f);

    luaL_newmetatable(L, "OutputPort");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, OutputPort_m);
    luaL_register(L, "rtt.OutputPort", OutputPort_f);

    luaL_newmetatable(L, "Variable");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, Variable_m);
    luaL_register(L, "rtt.Variable", Variable_f);

    luaL_newmetatable(L, "Property");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, Property_m);
    luaL_register(L, "rtt.Property", Property_f);

    luaL_newmetatable(L, "Attribute");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, Attribute_m);
    luaL_register(L, "rtt.Attribute", Attribute_f);

    luaL_newmetatable(L, "EEHook");
    lua_pushvalue(L, -1); /* duplicates metatable */
    lua_setfield(L, -2, "__index");
    luaL_register(L, NULL, EEHook_m);
    luaL_register(L, "rtt.EEHook", EEHook_f);

    /* misc toplevel functions */
    luaL_register(L, "rtt", rtt_f);

    return 1;
}

/* store the TC to be returned by getTC() in registry */
int set_context_tc(TaskContext *tc, lua_State *L)
{
    TaskContext **new_tc;
    lua_pushstring(L, "this_TC");
    new_tc = (TaskContext**) lua_newuserdata(L, sizeof(TaskContext*));
    *new_tc = (TaskContext*) tc;
    luaL_getmetatable(L, "TaskContext");
    lua_setmetatable(L, -2);
    lua_rawset(L, LUA_REGISTRYINDEX);
    return 0;
}


/* call a zero arity function with a boolean return value
 * used to call various hooks */
bool call_func(lua_State *L, const char *fname, TaskContext *tc,
           int require_function, int require_result)
{
    bool ret = true;
    int num_res = (require_result != 0) ? 1 : 0;
    lua_getglobal(L, fname);

    if(lua_isnil(L, -1)) {
        lua_pop(L, 1);
        if(require_function)
            luaL_error(L, "%s: no (required) Lua function %s", tc->getName().c_str(), fname);
        else
            goto out;
    }

    if (lua_pcall(L, 0, num_res, 0) != 0) {
        Logger::log(Logger::Error) << "LuaComponent '"<< tc->getName()  <<"': error calling function "
                       << fname << ": " << lua_tostring(L, -1) << endlog();
        lua_pop(L, 1);
        ret = false;
        goto out;
    }

    if(require_result) {
        if (!lua_isboolean(L, -1)) {
            Logger::log(Logger::Error) << "LuaComponent '" << tc->getName() << "': " << fname
                           << " must return a bool but returned a "
                           << lua_typename(L, lua_type(L, -1)) << endlog();
            lua_pop(L, 1);
            ret = false;
            goto out;
        }
        ret = lua_toboolean(L, -1);
        lua_pop(L, 1); /* pop result */
    }
 out:
    return ret;
}