/*******************************************************************************
 * xspf.c : XSPF playlist import functions
 *******************************************************************************
 * Copyright (C) 2006 the VideoLAN team
 * $Id: 7761434f04a7b4c126bda26233bc85931db67f6e $
 *
 * Authors: Daniel Stränger <vlc at schmaller dot de>
 *          Yoann Peronneau <yoann@videolan.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.
 ******************************************************************************/
/**
 * \file modules/demux/playlist/xspf.c
 * \brief XSPF playlist import functions
 */

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

#include <vlc_common.h>
#include <vlc_demux.h>

#include <vlc_xml.h>
#include <vlc_strings.h>
#include <vlc_url.h>
#include "xspf.h"
#include "playlist.h"

struct demux_sys_t
{
    input_item_t **pp_tracklist;
    int i_tracklist_entries;
    int i_track_id;
    char * psz_base;
};

static int Control( demux_t *, int, va_list );
static int Demux( demux_t * );

/**
 * \brief XSPF submodule initialization function
 */
int Import_xspf( vlc_object_t *p_this )
{
    DEMUX_BY_EXTENSION_OR_FORCED_MSG( ".xspf", "xspf-open",
                                      "using XSPF playlist reader" );
    return VLC_SUCCESS;
}

void Close_xspf( vlc_object_t *p_this )
{
    demux_t *p_demux = (demux_t *)p_this;
    demux_sys_t *p_sys = p_demux->p_sys;
    for( int i = 0; i < p_sys->i_tracklist_entries; i++ )
    {
        if( p_sys->pp_tracklist[i] )
            vlc_gc_decref( p_sys->pp_tracklist[i] );
    }
    free( p_sys->pp_tracklist );
    free( p_sys->psz_base );
    free( p_sys );
}

/**
 * \brief demuxer function for XSPF parsing
 */
int Demux( demux_t *p_demux )
{
    int i_ret = -1;
    xml_t *p_xml = NULL;
    xml_reader_t *p_xml_reader = NULL;
    char *psz_name = NULL;
    input_item_t *p_current_input = GetCurrentItem(p_demux);
    p_demux->p_sys->pp_tracklist = NULL;
    p_demux->p_sys->i_tracklist_entries = 0;
    p_demux->p_sys->i_track_id = -1;
    p_demux->p_sys->psz_base = NULL;

    /* create new xml parser from stream */
    p_xml = xml_Create( p_demux );
    if( !p_xml )
        goto end;

    p_xml_reader = xml_ReaderCreate( p_xml, p_demux->s );
    if( !p_xml_reader )
        goto end;

    /* locating the root node */
    do
    {
        if( xml_ReaderRead( p_xml_reader ) != 1 )
        {
            msg_Err( p_demux, "can't read xml stream" );
            goto end;
        }
    } while( xml_ReaderNodeType( p_xml_reader ) != XML_READER_STARTELEM );

    /* checking root node name */
    psz_name = xml_ReaderName( p_xml_reader );
    if( !psz_name || strcmp( psz_name, "playlist" ) )
    {
        msg_Err( p_demux, "invalid root node name: %s", psz_name );
        free( psz_name );
        goto end;
    }
    free( psz_name );

    input_item_node_t *p_subitems =
        input_item_node_Create( p_current_input );

    i_ret = parse_playlist_node( p_demux, p_subitems,
                                 p_xml_reader, "playlist" ) ? 0 : -1;

    for( int i = 0 ; i < p_demux->p_sys->i_tracklist_entries ; i++ )
    {
        input_item_t *p_new_input = p_demux->p_sys->pp_tracklist[i];
        if( p_new_input )
        {
            input_item_node_AppendItem( p_subitems, p_new_input );
        }
    }

    input_item_node_PostAndDelete( p_subitems );

end:
    vlc_gc_decref(p_current_input);
    if( p_xml_reader )
        xml_ReaderDelete( p_xml, p_xml_reader );
    if( p_xml )
        xml_Delete( p_xml );
    return i_ret; /* Needed for correct operation of go back */
}

/** \brief dummy function for demux callback interface */
static int Control( demux_t *p_demux, int i_query, va_list args )
{
    VLC_UNUSED(p_demux); VLC_UNUSED(i_query); VLC_UNUSED(args);
    return VLC_EGENERIC;
}

/**
 * \brief parse the root node of a XSPF playlist
 * \param p_demux demuxer instance
 * \param p_input_item current input item
 * \param p_xml_reader xml reader instance
 * \param psz_element name of element to parse
 */
static bool parse_playlist_node COMPLEX_INTERFACE
{
    input_item_t *p_input_item = p_input_node->p_item;
    char *psz_name = NULL;
    char *psz_value = NULL;
    bool b_version_found = false;
    int i_node;
    bool b_ret = false;
    xml_elem_hnd_t *p_handler = NULL;

    xml_elem_hnd_t pl_elements[] =
        { {"title",        SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"creator",      SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"annotation",   SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"info",         SIMPLE_CONTENT,  {NULL} },
          {"location",     SIMPLE_CONTENT,  {NULL} },
          {"identifier",   SIMPLE_CONTENT,  {NULL} },
          {"image",        SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"date",         SIMPLE_CONTENT,  {NULL} },
          {"license",      SIMPLE_CONTENT,  {NULL} },
          {"attribution",  COMPLEX_CONTENT, {.cmplx = skip_element} },
          {"link",         SIMPLE_CONTENT,  {NULL} },
          {"meta",         SIMPLE_CONTENT,  {NULL} },
          {"extension",    COMPLEX_CONTENT, {.cmplx = parse_extension_node} },
          {"trackList",    COMPLEX_CONTENT, {.cmplx = parse_tracklist_node} },
          {NULL,           UNKNOWN_CONTENT, {NULL} }
        };

    /* read all playlist attributes */
    while( xml_ReaderNextAttr( p_xml_reader ) == VLC_SUCCESS )
    {
        psz_name = xml_ReaderName( p_xml_reader );
        psz_value = xml_ReaderValue( p_xml_reader );
        if( !psz_name || !psz_value )
        {
            msg_Err( p_demux, "invalid xml stream @ <playlist>" );
            goto end;
        }
        /* attribute: version */
        if( !strcmp( psz_name, "version" ) )
        {
            b_version_found = true;
            if( strcmp( psz_value, "0" ) && strcmp( psz_value, "1" ) )
                msg_Warn( p_demux, "unsupported XSPF version" );
        }
        /* attribute: xmlns */
        else if( !strcmp( psz_name, "xmlns" ) || !strcmp( psz_name, "xmlns:vlc" ) )
            ;
        else if( !strcmp( psz_name, "xml:base" ) )
        {
            p_demux->p_sys->psz_base = strdup( psz_value );
        }
        /* unknown attribute */
        else
            msg_Warn( p_demux, "invalid <playlist> attribute:\"%s\"", psz_name);

        free( psz_name );
        free( psz_value );
    }
    /* attribute version is mandatory !!! */
    if( !b_version_found )
        msg_Warn( p_demux, "<playlist> requires \"version\" attribute" );

    /* parse the child elements - we only take care of <trackList> */
    psz_name = NULL;
    psz_value = NULL;
    while( xml_ReaderRead( p_xml_reader ) == 1 )
    {
        i_node = xml_ReaderNodeType( p_xml_reader );
        switch( i_node )
        {
            case XML_READER_NONE:
                break;
            case XML_READER_STARTELEM:
                /*  element start tag  */
                psz_name = xml_ReaderName( p_xml_reader );
                if( !psz_name || !*psz_name )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    goto end;
                }
                /* choose handler */
                for( p_handler = pl_elements;
                     p_handler->name && strcmp( psz_name, p_handler->name );
                     p_handler++ );
                if( !p_handler->name )
                {
                    msg_Err( p_demux, "unexpected element <%s>", psz_name );
                    goto end;
                }
                FREE_NAME();
                /* complex content is parsed in a separate function */
                if( p_handler->type == COMPLEX_CONTENT )
                {
                    FREE_VALUE();
                    if( p_handler->pf_handler.cmplx( p_demux,
                                                     p_input_node,
                                                     p_xml_reader,
                                                     p_handler->name ) )
                    {
                        p_handler = NULL;
                    }
                    else
                    {
                        return false;
                    }
                }
                break;

            case XML_READER_TEXT:
                /* simple element content */
                free( psz_value );
                psz_value = xml_ReaderValue( p_xml_reader );
                if( !psz_value )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    goto end;
                }
                break;

            case XML_READER_ENDELEM:
                /* element end tag */
                psz_name = xml_ReaderName( p_xml_reader );
                if( !psz_name )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    goto end;
                }
                /* leave if the current parent node <playlist> is terminated */
                if( !strcmp( psz_name, psz_element ) )
                {
                    b_ret = true;
                    goto end;
                }
                /* there MUST have been a start tag for that element name */
                if( !p_handler || !p_handler->name
                    || strcmp( p_handler->name, psz_name ))
                {
                    msg_Err( p_demux, "there's no open element left for <%s>",
                             psz_name );
                    goto end;
                }

                if( p_handler->pf_handler.smpl )
                {
                    p_handler->pf_handler.smpl( p_input_item, p_handler->name,
                                                psz_value );
                }
                FREE_ATT();
                p_handler = NULL;
                break;

            default:
                /* unknown/unexpected xml node */
                msg_Err( p_demux, "unexpected xml node %i", i_node );
                goto end;
        }
    }

end:
    free( psz_name );
    free( psz_value );
    return b_ret;
}

/**
 * \brief parses the tracklist node which only may contain <track>s
 */
static bool parse_tracklist_node COMPLEX_INTERFACE
{
    VLC_UNUSED(psz_element);
    char *psz_name;
    int i_ntracks = 0;

    /* now parse the <track>s */
    while( xml_ReaderRead( p_xml_reader ) == 1 )
    {
        int i_node = xml_ReaderNodeType( p_xml_reader );
        if( i_node == XML_READER_STARTELEM )
        {
            char *psz_eltname = xml_ReaderName( p_xml_reader );
            if( !psz_eltname )
            {
                msg_Err( p_demux, "unexpected end of xml data" );
                free( psz_eltname );
                return false;
            }
            if( strcmp( psz_eltname, "track") )
            {
                msg_Err( p_demux, "unexpected child of <trackList>: <%s>",
                         psz_eltname );
                free( psz_eltname );
                return false;
            }
            free( psz_eltname );

            /* parse the track data in a separate function */
            if( parse_track_node( p_demux, p_input_node,
                                  p_xml_reader, "track" ) )
                i_ntracks++;
        }
        else if( i_node == XML_READER_ENDELEM )
            break;
    }

    /* the <trackList> has to be terminated */
    if( xml_ReaderNodeType( p_xml_reader ) != XML_READER_ENDELEM )
    {
        msg_Err( p_demux, "there's a missing </trackList>" );
        return false;
    }
    psz_name = xml_ReaderName( p_xml_reader );
    if( !psz_name || strcmp( psz_name, "trackList" ) )
    {
        msg_Err( p_demux, "expected: </trackList>, found: </%s>", psz_name );
        free( psz_name );
        return false;
    }
    free( psz_name );

    msg_Dbg( p_demux, "parsed %i tracks successfully", i_ntracks );
    return true;
}

/**
 * \brief parse one track element
 * \param COMPLEX_INTERFACE
 */
static bool parse_track_node COMPLEX_INTERFACE
{
    input_item_t *p_input_item = p_input_node->p_item;
    char *psz_name = NULL;
    char *psz_value = NULL;
    xml_elem_hnd_t *p_handler = NULL;
    demux_sys_t *p_sys = p_demux->p_sys;
    bool b_ret = false;

    xml_elem_hnd_t track_elements[] =
        { {"location",     SIMPLE_CONTENT,  {NULL} },
          {"identifier",   SIMPLE_CONTENT,  {NULL} },
          {"title",        SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"creator",      SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"annotation",   SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"info",         SIMPLE_CONTENT,  {NULL} },
          {"image",        SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"album",        SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"trackNum",     SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"duration",     SIMPLE_CONTENT,  {.smpl = set_item_info} },
          {"link",         SIMPLE_CONTENT,  {NULL} },
          {"meta",         SIMPLE_CONTENT,  {NULL} },
          {"extension",    COMPLEX_CONTENT, {.cmplx = parse_extension_node} },
          {NULL,           UNKNOWN_CONTENT, {NULL} }
        };

    input_item_t *p_new_input = input_item_New( p_demux, NULL, NULL );
    input_item_node_t *p_new_node = input_item_node_Create( p_new_input );

    if( !p_new_input )
    {
        /* malloc has failed for input_item_New, so bailout early */
        return false;
    }

    /* reset i_track_id */
    p_sys->i_track_id = -1;

    while( xml_ReaderRead( p_xml_reader ) == 1 )
    {
        int i_node = xml_ReaderNodeType( p_xml_reader );
        switch( i_node )
        {
            case XML_READER_NONE:
                break;

            case XML_READER_STARTELEM:
                /*  element start tag  */
                psz_name = xml_ReaderName( p_xml_reader );
                if( !psz_name || !*psz_name )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    goto end;
                }
                /* choose handler */
                for( p_handler = track_elements;
                     p_handler->name && strcmp( psz_name, p_handler->name );
                     p_handler++ );
                if( !p_handler->name )
                {
                    msg_Err( p_demux, "unexpected element <%s>", psz_name );
                    goto end;
                }
                FREE_NAME();
                /* complex content is parsed in a separate function */
                if( p_handler->type == COMPLEX_CONTENT )
                {
                    FREE_VALUE();

                    bool b_res = p_handler->pf_handler.cmplx( p_demux,
                                                        p_new_node,
                                                        p_xml_reader,
                                                        p_handler->name );
                    if( b_res )
                    {
                        p_handler = NULL;
                    }
                    else
                    {
                        return false;
                    }
                }
                break;

            case XML_READER_TEXT:
                /* simple element content */
                free( psz_value );
                psz_value = xml_ReaderValue( p_xml_reader );
                if( !psz_value )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    goto end;
                }
                break;

            case XML_READER_ENDELEM:
                /* element end tag */
                psz_name = xml_ReaderName( p_xml_reader );
                if( !psz_name )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    goto end;
                }

                /* leave if the current parent node <track> is terminated */
                if( !strcmp( psz_name, psz_element ) )
                {
                    free( psz_name );
                    free( psz_value );

                    /* Make sure we have a URI */
                    char *psz_uri = input_item_GetURI( p_new_input );
                    if( !psz_uri )
                    {
                        input_item_SetURI( p_new_input, "vlc://nop" );
                    }
                    free( psz_uri );

                    if( p_sys->i_track_id < 0
                     || p_sys->i_track_id >= (SIZE_MAX / sizeof(p_new_input)) )
                    {
                        input_item_node_AppendNode( p_input_node, p_new_node );
                        vlc_gc_decref( p_new_input );
                        return true;
                    }

                    if( p_sys->i_track_id >= p_sys->i_tracklist_entries )
                    {
                        input_item_t **pp;
                        pp = realloc( p_sys->pp_tracklist,
                            (p_sys->i_track_id + 1) * sizeof(*pp) );
                        if( !pp )
                        {
                            vlc_gc_decref( p_new_input );
                            return false;
                        }
                        p_sys->pp_tracklist = pp;
                        while( p_sys->i_track_id >= p_sys->i_tracklist_entries )
                            pp[p_sys->i_tracklist_entries++] = NULL;
                    }
                    else if( p_sys->pp_tracklist[p_sys->i_track_id] != NULL )
                    {
                        msg_Err( p_demux, "track ID %d collision",
                                 p_sys->i_track_id );
                        vlc_gc_decref( p_new_input );
                        return false;
                    }

                    p_sys->pp_tracklist[ p_sys->i_track_id ] = p_new_input;
                    return true;
                }
                /* there MUST have been a start tag for that element name */
                if( !p_handler || !p_handler->name
                    || strcmp( p_handler->name, psz_name ))
                {
                    msg_Err( p_demux, "there's no open element left for <%s>",
                             psz_name );
                    goto end;
                }

                /* special case: location */
                if( !strcmp( p_handler->name, "location" ) )
                {
                    if( psz_value == NULL )
                        input_item_SetURI( p_new_input, "vlc://nop" );
                    else
                    /* FIXME: This is broken. Scheme-relative (//...) locations
                     * and anchors (#...) are not resolved correctly. Also,
                     * host-relative (/...) and directory-relative locations
                     * ("relative path" in vernacular) should be resolved.
                     * Last, psz_base should default to the XSPF resource
                     * location if missing (not the current working directory).
                     * -- Courmisch */
                    if( p_sys->psz_base && !strstr( psz_value, "://" ) )
                    {
                        char* psz_tmp;
                        if( asprintf( &psz_tmp, "%s%s", p_sys->psz_base,
                                      psz_value ) == -1 )
                        {
                            goto end;
                        }
                        input_item_SetURI( p_new_input, psz_tmp );
                        free( psz_tmp );
                    }
                    else
                        input_item_SetURI( p_new_input, psz_value );
                    input_item_CopyOptions( p_input_item, p_new_input );
                }
                else
                {
                    /* there MUST be an item */
                    if( p_handler->pf_handler.smpl )
                    {
                        p_handler->pf_handler.smpl( p_new_input,
                                                    p_handler->name,
                                                    psz_value );
                        FREE_ATT();
                    }
                }
                FREE_ATT();
                p_handler = NULL;
                break;

            default:
                /* unknown/unexpected xml node */
                msg_Err( p_demux, "unexpected xml node %i", i_node );
                goto end;
        }
    }
    msg_Err( p_demux, "unexpected end of xml data" );

end:
    free( psz_name );
    free( psz_value );
    return b_ret;
}

/**
 * \brief handles the supported <track> sub-elements
 */
static bool set_item_info SIMPLE_INTERFACE
{
    /* exit if setting is impossible */
    if( !psz_name || !psz_value || !p_input )
        return false;

    /* re-convert xml special characters inside psz_value */
    resolve_xml_special_chars( psz_value );

    /* handle each info element in a separate "if" clause */
    if( !strcmp( psz_name, "title" ) )
    {
        input_item_SetTitle( p_input, psz_value );
    }
    else if( !strcmp( psz_name, "creator" ) )
    {
        input_item_SetArtist( p_input, psz_value );
    }
    else if( !strcmp( psz_name, "album" ) )
    {
        input_item_SetAlbum( p_input, psz_value );

    }
    else if( !strcmp( psz_name, "trackNum" ) )
    {
        input_item_SetTrackNum( p_input, psz_value );
    }
    else if( !strcmp( psz_name, "duration" ) )
    {
        long i_num = atol( psz_value );
        input_item_SetDuration( p_input, (mtime_t) i_num*1000 );
    }
    else if( !strcmp( psz_name, "annotation" ) )
    {
        input_item_SetDescription( p_input, psz_value );
    }
    else if( !strcmp( psz_name, "image" ) )
    {
        input_item_SetArtURL( p_input, psz_value );
    }
    return true;
}

/**
 * \brief handles the <vlc:option> elements
 */
static bool set_option SIMPLE_INTERFACE
{
    /* exit if setting is impossible */
    if( !psz_name || !psz_value || !p_input )
        return false;

    /* re-convert xml special characters inside psz_value */
    resolve_xml_special_chars( psz_value );

    input_item_AddOption( p_input, psz_value, 0 );

    return true;
}

/**
 * \brief parse the extension node of a XSPF playlist
 */
static bool parse_extension_node COMPLEX_INTERFACE
{
    input_item_t *p_input_item = p_input_node->p_item;
    char *psz_name = NULL;
    char *psz_value = NULL;
    char *psz_title = NULL;
    char *psz_application = NULL;
    int i_node;
    bool b_release_input_item = false;
    xml_elem_hnd_t *p_handler = NULL;
    input_item_t *p_new_input = NULL;

    xml_elem_hnd_t pl_elements[] =
        { {"vlc:node",   COMPLEX_CONTENT, {.cmplx = parse_extension_node} },
          {"vlc:item",   COMPLEX_CONTENT, {.cmplx = parse_extitem_node} },
          {"vlc:id",     SIMPLE_CONTENT, {NULL} },
          {"vlc:option", SIMPLE_CONTENT, {.smpl = set_option} },
          {NULL,    UNKNOWN_CONTENT, {NULL} }
        };

    /* read all extension node attributes */
    while( xml_ReaderNextAttr( p_xml_reader ) == VLC_SUCCESS )
    {
        psz_name = xml_ReaderName( p_xml_reader );
        psz_value = xml_ReaderValue( p_xml_reader );
        if( !psz_name || !psz_value )
        {
            msg_Err( p_demux, "invalid xml stream @ <vlc:node>" );
            FREE_ATT();
            return false;
        }
        /* attribute: title */
        if( !strcmp( psz_name, "title" ) )
        {
            resolve_xml_special_chars( psz_value );
            psz_title = psz_value;
        }
        /* extension attribute: application */
        else if( !strcmp( psz_name, "application" ) )
        {
            psz_application = psz_value;
        }
        /* unknown attribute */
        else
        {
            msg_Warn( p_demux, "invalid <%s> attribute:\"%s\"", psz_element,
                      psz_name );
            FREE_VALUE();
        }
        FREE_NAME();
        psz_value = NULL;
    }

    /* attribute title is mandatory except for <extension> */
    if( !strcmp( psz_element, "vlc:node" ) )
    {
        if( !psz_title )
        {
            msg_Warn( p_demux, "<vlc:node> requires \"title\" attribute" );
            return false;
        }
        p_new_input = input_item_NewWithType( VLC_OBJECT( p_demux ),
                          "vlc://nop", psz_title, 0, NULL, 0, -1,
                          ITEM_TYPE_DIRECTORY );
        if( p_new_input )
        {
            p_input_node =
                input_item_node_AppendItem( p_input_node, p_new_input );
            p_input_item = p_new_input;
            b_release_input_item = true;
        }
        free( psz_title );
    }
    else if( !strcmp( psz_element, "extension" ) )
    {
        if( !psz_application )
        {
            msg_Warn( p_demux, "<extension> requires \"application\" attribute" );
            return false;
        }
        /* Skip the extension if the application is not vlc
           This will skip all children of the current node */
        else if( strcmp( psz_application, "http://www.videolan.org/vlc/playlist/0" ) )
        {
            msg_Dbg( p_demux, "Skipping \"%s\" extension tag", psz_application );
            free( psz_application );
            /* Skip all children */
            while( xml_ReaderRead( p_xml_reader ) == 1 )
            {
                if( xml_ReaderNodeType( p_xml_reader ) == XML_READER_ENDELEM )
                {
                    char *psz_name = xml_ReaderName( p_xml_reader );
                    if( !strcmp( psz_name, "extension" ) )
                    {
                        free( psz_name );
                        break;
                    }
                    msg_Dbg( p_demux, "\tskipping \"%s\" extension child", psz_name );
                    free( psz_name );
                }
            }
            return true;
        }
    }
    free( psz_application );


    /* parse the child elements */
    while( xml_ReaderRead( p_xml_reader ) == 1 )
    {
        i_node = xml_ReaderNodeType( p_xml_reader );
        switch( i_node )
        {
            case XML_READER_NONE:
                break;
            case XML_READER_STARTELEM:
                /*  element start tag  */
                psz_name = xml_ReaderName( p_xml_reader );
                if( !psz_name || !*psz_name )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    FREE_ATT();
                    if( b_release_input_item ) vlc_gc_decref( p_new_input );
                    return false;
                }
                /* choose handler */
                for( p_handler = pl_elements;
                     p_handler->name && strcmp( psz_name, p_handler->name );
                     p_handler++ );
                if( !p_handler->name )
                {
                    msg_Err( p_demux, "unexpected element <%s>", psz_name );
                    FREE_ATT();
                    if( b_release_input_item ) vlc_gc_decref( p_new_input );
                    return false;
                }
                FREE_NAME();
                /* complex content is parsed in a separate function */
                if( p_handler->type == COMPLEX_CONTENT )
                {
                    if( p_handler->pf_handler.cmplx( p_demux,
                                                     p_input_node,
                                                     p_xml_reader,
                                                     p_handler->name ) )
                    {
                        p_handler = NULL;
                        FREE_ATT();
                    }
                    else
                    {
                        FREE_ATT();
                        if( b_release_input_item ) vlc_gc_decref( p_new_input );
                        return false;
                    }
                }
                break;

            case XML_READER_TEXT:
                /* simple element content */
                FREE_ATT();
                psz_value = xml_ReaderValue( p_xml_reader );
                if( !psz_value )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    FREE_ATT();
                    if( b_release_input_item ) vlc_gc_decref( p_new_input );
                    return false;
                }
                break;

            case XML_READER_ENDELEM:
                /* element end tag */
                psz_name = xml_ReaderName( p_xml_reader );
                if( !psz_name )
                {
                    msg_Err( p_demux, "invalid xml stream" );
                    FREE_ATT();
                    if( b_release_input_item ) vlc_gc_decref( p_new_input );
                    return false;
                }
                /* leave if the current parent node is terminated */
                if( !strcmp( psz_name, psz_element ) )
                {
                    FREE_ATT();
                    if( b_release_input_item ) vlc_gc_decref( p_new_input );
                    return true;
                }
                /* there MUST have been a start tag for that element name */
                if( !p_handler || !p_handler->name
                    || strcmp( p_handler->name, psz_name ))
                {
                    msg_Err( p_demux, "there's no open element left for <%s>",
                             psz_name );
                    FREE_ATT();
                    if( b_release_input_item ) vlc_gc_decref( p_new_input );
                    return false;
                }

                /* special tag <vlc:id> */
                if( !strcmp( p_handler->name, "vlc:id" ) )
                {
                    p_demux->p_sys->i_track_id = atoi( psz_value );
                }
                else if( p_handler->pf_handler.smpl )
                {
                    p_handler->pf_handler.smpl( p_input_item, p_handler->name,
                                                psz_value );
                }
                FREE_ATT();
                p_handler = NULL;
                break;

            default:
                /* unknown/unexpected xml node */
                msg_Err( p_demux, "unexpected xml node %i", i_node );
                FREE_ATT();
                if( b_release_input_item ) vlc_gc_decref( p_new_input );
                return false;
        }
        FREE_NAME();
    }
    if( b_release_input_item ) vlc_gc_decref( p_new_input );
    return false;
}

/**
 * \brief parse the extension item node of a XSPF playlist
 */
static bool parse_extitem_node COMPLEX_INTERFACE
{
    VLC_UNUSED(psz_element);
    input_item_t *p_new_input = NULL;
    int i_tid = -1;

    /* read all extension item attributes */
    while( xml_ReaderNextAttr( p_xml_reader ) == VLC_SUCCESS )
    {
        char *psz_name = xml_ReaderName( p_xml_reader );
        char *psz_value = xml_ReaderValue( p_xml_reader );
        if( !psz_name || !psz_value )
        {
            msg_Err( p_demux, "invalid xml stream @ <vlc:item>" );
            free( psz_name );
            free( psz_value );
            return false;
        }
        /* attribute: href */
        if( !strcmp( psz_name, "tid" ) )
        {
            i_tid = atoi( psz_value );
        }
        /* unknown attribute */
        else
            msg_Warn( p_demux, "invalid <vlc:item> attribute:\"%s\"", psz_name);

        free( psz_name );
        free( psz_value );
    }

    /* attribute href is mandatory */
    if( i_tid < 0 )
    {
        msg_Warn( p_demux, "<vlc:item> requires \"tid\" attribute" );
        return false;
    }

    if( i_tid >= p_demux->p_sys->i_tracklist_entries )
    {
        msg_Warn( p_demux, "invalid \"tid\" attribute" );
        return false;
    }

    p_new_input = p_demux->p_sys->pp_tracklist[ i_tid ];
    if( p_new_input )
    {
        input_item_node_AppendItem( p_input_node, p_new_input );
        vlc_gc_decref( p_new_input );
        p_demux->p_sys->pp_tracklist[i_tid] = NULL;
    }

    /* kludge for #1293 - XTAG sends ENDELEM for self closing tag */
    /* (libxml sends NONE) */
    xml_ReaderRead( p_xml_reader );

    return true;
}

/**
 * \brief skips complex element content that we can't manage
 */
static bool skip_element COMPLEX_INTERFACE
{
    VLC_UNUSED(p_demux); VLC_UNUSED(p_input_node);

    while( xml_ReaderRead( p_xml_reader ) == 1 )
    {
        if( xml_ReaderNodeType( p_xml_reader ) == XML_READER_ENDELEM )
        {
            char *psz_endname = xml_ReaderName( p_xml_reader );
            if( !psz_endname )
                return false;
            if( !strcmp( psz_element, psz_endname ) )
            {
                free( psz_endname );
                return true;
            }
            else
                free( psz_endname );
        }
    }
    return false;
}
