vlc/modules/misc/lua/libs/objects.c

/*****************************************************************************
 * objects.c: Generic lua<->vlc object wrapper
 *****************************************************************************
 * Copyright (C) 2007-2008 the VideoLAN team
 * $Id$
 *
 * Authors: Antoine Cellerier <dionoea at videolan tod org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#ifndef  _GNU_SOURCE
#   define  _GNU_SOURCE
#endif

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>

#include <lua.h>        /* Low level lua C API */
#include <lauxlib.h>    /* Higher level C API */

#include "../vlc.h"
#include "../libs.h"
#include "objects.h"
#include "playlist.h"
#include "input.h"

typedef struct
{
    vlc_object_t *p_obj;
} vlclua_object_t;

/*****************************************************************************
 * Generic vlc_object_t wrapper creation
 *****************************************************************************/
int __vlclua_push_vlc_object( lua_State *L, vlc_object_t *p_obj,
                              lua_CFunction pf_gc )
{
    vlc_object_t **udata = (vlc_object_t **)
        lua_newuserdata( L, sizeof( vlc_object_t * ) );
    *udata = p_obj;

    if( luaL_newmetatable( L, "vlc_object" ) )
    {
        /* Hide the metatable */
        lua_pushstring( L, "none of your business" );
        lua_setfield( L, -2, "__metatable" );
        if( pf_gc ) /* FIXME */
        {
            /* Set the garbage collector if needed */
            lua_pushcfunction( L, pf_gc );
            lua_setfield( L, -2, "__gc" );
        }
    }
    lua_setmetatable( L, -2 );
    return 1;
}

int vlclua_gc_release( lua_State *L )
{
    vlc_object_t **p_obj = (vlc_object_t **)luaL_checkudata( L, 1, "vlc_object" );
    lua_pop( L, 1 );
    vlc_object_release( *p_obj );
    return 0;
}

static int vlc_object_type_from_string( const char *psz_name )
{
    static const struct
    {
        int i_type;
        const char *psz_name;
    } pp_objects[] =
        { { VLC_OBJECT_INPUT, "input" },
          { VLC_OBJECT_DECODER, "decoder" },
          { VLC_OBJECT_VOUT, "vout" },
          { VLC_OBJECT_AOUT, "aout" },
          { VLC_OBJECT_GENERIC, "generic" },
          { 0, "" } };
    int i;
    for( i = 0; pp_objects[i].i_type; i++ )
    {
        if( !strcmp( psz_name, pp_objects[i].psz_name ) )
            return pp_objects[i].i_type;
    }
    return 0;
}

static int vlc_object_search_mode_from_string( const char *psz_name )
{
    static const struct
    {
        int i_mode;
        const char *psz_name;
    } pp_modes[] =
        { { FIND_PARENT, "parent" },
          { FIND_CHILD, "child" },
          { FIND_ANYWHERE, "anywhere" },
          { 0, "" } };
    int i;
    for( i = 0; pp_modes[i].i_mode; i++ )
    {
        if( !strcmp( psz_name, pp_modes[i].psz_name ) )
            return pp_modes[i].i_mode;
    }
    return 0;
}

static int vlclua_object_find( lua_State *L )
{
    const char *psz_type = luaL_checkstring( L, 2 );
    const char *psz_mode = luaL_checkstring( L, 3 );

    vlc_object_t *p_this;
    int i_type = vlc_object_type_from_string( psz_type );
    int i_mode = vlc_object_search_mode_from_string( psz_mode );
    vlc_object_t *p_result;

    if( !i_type )
        return luaL_error( L, "\"%s\" is not a valid object type.", psz_type );
    if( !i_mode )
        return luaL_error( L, "\"%s\" is not a valid search mode.", psz_mode );

    if( lua_type( L, 1 ) == LUA_TNIL )
        p_this = vlclua_get_this( L );
    else
    {
        vlc_object_t **p_obj = luaL_checkudata( L, 1, "vlc_object" );
        p_this = *p_obj;
    }

    p_result = vlc_object_find( p_this, i_type, i_mode );
    if( !p_result )
        lua_pushnil( L );
    else
        vlclua_push_vlc_object( L, p_result, vlclua_gc_release );
    return 1;
}

static int vlclua_object_find_name( lua_State *L )
{
    const char *psz_name = luaL_checkstring( L, 2 );
    const char *psz_mode = luaL_checkstring( L, 3 );

    vlc_object_t *p_this;
    int i_mode = vlc_object_search_mode_from_string( psz_mode );
    vlc_object_t *p_result;

    if( !i_mode )
        return luaL_error( L, "\"%s\" is not a valid search mode.",
                           psz_mode );

    if( lua_type( L, 1 ) == LUA_TNIL )
        p_this = vlclua_get_this( L );
    else
    {
        vlc_object_t **p_obj = luaL_checkudata( L, 1, "vlc_object" );
        p_this = *p_obj;
    }

    p_result = vlc_object_find_name( p_this, psz_name, i_mode );
    if( !p_result )
        lua_pushnil( L );
    else
        vlclua_push_vlc_object( L, p_result, vlclua_gc_release );
    return 1;
}

static int vlclua_get_libvlc( lua_State *L )
{
    vlclua_push_vlc_object( L, vlclua_get_this( L )->p_libvlc,
                            NULL );
    return 1;
}

static int vlclua_get_playlist( lua_State *L )
{
    playlist_t *p_playlist = vlclua_get_playlist_internal( L );
    if( p_playlist )
    {
        vlclua_push_vlc_object( L, p_playlist, vlclua_gc_release );
    }
    else lua_pushnil( L );
    //vlclua_release_playlist_internal( p_playlist );
    return 1;
}

static int vlclua_get_input( lua_State *L )
{
    input_thread_t *p_input = vlclua_get_input_internal( L );
    if( p_input )
    {
        vlclua_push_vlc_object( L, p_input, vlclua_gc_release );
    }
    else lua_pushnil( L );
    return 1;
}

/*****************************************************************************
 *
 *****************************************************************************/
static const luaL_Reg vlclua_object_reg[] = {
    { "input", vlclua_get_input },
    { "playlist", vlclua_get_playlist },
    { "libvlc", vlclua_get_libvlc },
    { "find", vlclua_object_find },
    { "find_name", vlclua_object_find_name },
    { NULL, NULL }
};

void luaopen_object( lua_State *L )
{
    lua_newtable( L );
    luaL_register( L, NULL, vlclua_object_reg );
    lua_setfield( L, -2, "object" );
}