vlc/src/input/stream.c

/*****************************************************************************
 * stream.c
 *****************************************************************************
 * Copyright (C) 1999-2004 VLC authors and VideoLAN
 * Copyright 2008-2015 Rémi Denis-Courmont
 *
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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.
 *****************************************************************************/

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

#include <assert.h>
#include <stdbool.h>
#include <stdalign.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#include <vlc_common.h>
#include <vlc_block.h>
#include <vlc_access.h>
#include <vlc_charset.h>
#include <vlc_interrupt.h>
#include <vlc_stream_extractor.h>

#include <libvlc.h>
#include "stream.h"
#include "mrl_helpers.h"

typedef struct stream_priv_t
{
    stream_t stream;
    void (*destroy)(stream_t *);
    block_t *block;
    block_t *peek;
    uint64_t offset;
    bool eof;

    /* UTF-16 and UTF-32 file reading */
    struct {
        vlc_iconv_t   conv;
        unsigned char char_width;
        bool          little_endian;
    } text;

    max_align_t private_data[];
} stream_priv_t;

/**
 * Allocates a VLC stream object
 */
stream_t *vlc_stream_CustomNew(vlc_object_t *parent,
                               void (*destroy)(stream_t *), size_t size,
                               const char *type_name)
{
    stream_priv_t *priv = vlc_custom_create(parent, sizeof (*priv) + size,
                                            type_name);
    if (unlikely(priv == NULL))
        return NULL;

    stream_t *s = &priv->stream;

    s->psz_name = NULL;
    s->psz_url = NULL;
    s->psz_location = NULL;
    s->psz_filepath = NULL;
    s->b_preparsing = false;
    s->p_input_item = NULL;
    s->s = NULL;
    s->out = NULL;
    s->pf_read = NULL;
    s->pf_block = NULL;
    s->pf_readdir = NULL;
    s->pf_demux = NULL;
    s->pf_seek = NULL;
    s->pf_control = NULL;
    s->p_sys = NULL;
    s->ops = NULL;
    assert(destroy != NULL);
    priv->destroy = destroy;
    priv->block = NULL;
    priv->peek = NULL;
    priv->offset = 0;
    priv->eof = false;

    /* UTF16 and UTF32 text file conversion */
    priv->text.conv = (vlc_iconv_t)(-1);
    priv->text.char_width = 1;
    priv->text.little_endian = false;

    return &priv->stream;
}

#define stream_priv(s) container_of(s, stream_priv_t, stream)

void *vlc_stream_Private(stream_t *stream)
{
    return stream_priv(stream)->private_data;
}

stream_t *vlc_stream_CommonNew(vlc_object_t *parent,
                               void (*destroy)(stream_t *))
{
    return vlc_stream_CustomNew(parent, destroy, 0, "stream");
}

void stream_CommonDelete(stream_t *s)
{
    stream_priv_t *priv = stream_priv(s);

    if (priv->text.conv != (vlc_iconv_t)(-1))
        vlc_iconv_close(priv->text.conv);

    if (priv->peek != NULL)
        block_Release(priv->peek);
    if (priv->block != NULL)
        block_Release(priv->block);

    free(s->psz_url);
    vlc_object_delete(s);
}

/**
 * Destroy a stream
 */
void vlc_stream_Delete(stream_t *s)
{
    stream_priv_t *priv = stream_priv(s);

    if (s->ops != NULL && s->ops->close != NULL) {
        s->ops->close(s);
    }
    priv->destroy(s);
    stream_CommonDelete(s);
}

stream_t *(vlc_stream_NewURL)(vlc_object_t *p_parent, const char *psz_url)
{
    if( !psz_url )
        return NULL;

    stream_t *s = stream_AccessNew( p_parent, NULL, NULL, false, psz_url );
    if( s == NULL )
        msg_Err( p_parent, "no suitable access module for `%s'", psz_url );
    else
        s = stream_FilterAutoNew(s);
    return s;
}

stream_t *(vlc_stream_NewMRL)(vlc_object_t* parent, const char* mrl )
{
    stream_t* stream = vlc_stream_NewURL( parent, mrl );

    if( stream == NULL )
        return NULL;

    char const* anchor = strchr( mrl, '#' );

    if( anchor == NULL )
        return stream;

    char const* extra;
    if( stream_extractor_AttachParsed( &stream, anchor + 1, &extra ) )
    {
        msg_Err( parent, "unable to open %s", mrl );
        vlc_stream_Delete( stream );
        return NULL;
    }

    if( extra && *extra )
        msg_Warn( parent, "ignoring extra fragment data: %s", extra );

    return stream;
}

/**
 * Read from the stream until first newline.
 * \param s Stream handle to read from
 * \return A pointer to the allocated output string. You need to free this when you are done.
 */
#define STREAM_PROBE_LINE 2048
#define STREAM_LINE_MAX (2048*100)
char *vlc_stream_ReadLine( stream_t *s )
{
    stream_priv_t *priv = stream_priv(s);

    /* Let's fail quickly if this is a readdir access */
    if( (s->ops != NULL && s->ops->stream.read == NULL && s->ops->stream.block == NULL) ||
            (s->ops == NULL && s->pf_read == NULL && s->pf_block == NULL) )
        return NULL;

    /* BOM detection */
    if( vlc_stream_Tell( s ) == 0 )
    {
        const uint8_t *p_data;
        ssize_t i_data = vlc_stream_Peek( s, &p_data, 2 );

        if( i_data <= 0 )
            return NULL;

        if( unlikely(priv->text.conv != (vlc_iconv_t)-1) )
        {   /* seek back to beginning? reset */
            vlc_iconv_close( priv->text.conv );
            priv->text.conv = (vlc_iconv_t)-1;
        }
        priv->text.char_width = 1;
        priv->text.little_endian = false;

        if( i_data >= 2 )
        {
            const char *psz_encoding = NULL;
            bool little_endian = false;

            if( !memcmp( p_data, "\xFF\xFE", 2 ) )
            {
                psz_encoding = "UTF-16LE";
                little_endian = true;
            }
            else if( !memcmp( p_data, "\xFE\xFF", 2 ) )
            {
                psz_encoding = "UTF-16BE";
            }

            /* Open the converter if we need it */
            if( psz_encoding != NULL )
            {
                msg_Dbg( s, "UTF-16 BOM detected" );
                priv->text.conv = vlc_iconv_open( "UTF-8", psz_encoding );
                if( unlikely(priv->text.conv == (vlc_iconv_t)-1) )
                {
                    msg_Err( s, "iconv_open failed" );
                    return NULL;
                }
                priv->text.char_width = 2;
                priv->text.little_endian = little_endian;
            }
        }
    }

    size_t i_line = 0;
    const uint8_t *p_data;

    for( ;; )
    {
        size_t i_peek = i_line == 0 ? STREAM_PROBE_LINE
                                    : __MIN( i_line * 2, STREAM_LINE_MAX );

        /* Probe more data */
        ssize_t i_data = vlc_stream_Peek( s, &p_data, i_peek );
        if( i_data <= 0 )
            return NULL;

        /* Deal here with lone-byte incomplete UTF-16 sequences at EOF
           that we won't be able to process anyway */
        if( i_data < priv->text.char_width )
        {
            assert( priv->text.char_width == 2 );
            uint8_t inc;
            ssize_t i_inc = vlc_stream_Read( s, &inc, priv->text.char_width );
            assert( i_inc == i_data );
            if( i_inc > 0 )
                msg_Err( s, "discarding incomplete UTF-16 sequence at EOF: 0x%02x", inc );
            return NULL;
        }

        /* Keep to text encoding character width boundary */
        if( i_data % priv->text.char_width )
            i_data = i_data - ( i_data % priv->text.char_width );

        if( (size_t) i_data == i_line )
            break; /* No more data */

        assert( (size_t) i_data > i_line );

        /* Resume search for an EOL where we left off */
        const uint8_t *p_cur = p_data + i_line, *psz_eol;

        /* FIXME: <CR> behavior varies depending on where buffer
           boundaries happen to fall; a <CR><LF> across the boundary
           creates a bogus empty line. */
        if( priv->text.char_width == 1 )
        {
            /* UTF-8: 0A <LF> */
            psz_eol = memchr( p_cur, '\n', i_data - i_line );
            if( psz_eol == NULL )
                /* UTF-8: 0D <CR> */
                psz_eol = memchr( p_cur, '\r', i_data - i_line );
        }
        else
        {
            const uint8_t *p_last = p_data + i_data - priv->text.char_width;
            uint16_t eol = priv->text.little_endian ? 0x0A00 : 0x000A;

            assert( priv->text.char_width == 2 );
            psz_eol = NULL;
            /* UTF-16: 000A <LF> */
            for( const uint8_t *p = p_cur; p <= p_last; p += 2 )
            {
                if( U16_AT( p ) == eol )
                {
                     psz_eol = p;
                     break;
                }
            }

            if( psz_eol == NULL )
            {   /* UTF-16: 000D <CR> */
                eol = priv->text.little_endian ? 0x0D00 : 0x000D;
                for( const uint8_t *p = p_cur; p <= p_last; p += 2 )
                {
                    if( U16_AT( p ) == eol )
                    {
                        psz_eol = p;
                        break;
                    }
                }
            }
        }

        if( psz_eol )
        {
            i_line = (psz_eol - p_data) + priv->text.char_width;
            /* We have our line */
            break;
        }

        i_line = i_data;

        if( i_line >= STREAM_LINE_MAX )
        {
            msg_Err( s, "line too long, exceeding %zu bytes",
                     (size_t) STREAM_LINE_MAX );
            return NULL;
        }
    }

    if( i_line == 0 ) /* We failed to read any data, probably EOF */
        return NULL;

    /* If encoding conversion is required, UTF-8 needs at most 150%
       as long a buffer as UTF-16 */
    size_t i_line_conv = priv->text.char_width == 1 ? i_line : i_line * 3 / 2;
    char *p_line = malloc( i_line_conv + 1 ); /* +1 for easy \0 append */
    if( !p_line )
        return NULL;
    void *p_read = p_line;

    if( priv->text.char_width > 1 )
    {
        size_t i_in = i_line, i_out = i_line_conv;
        const char * p_in = (char *) p_data;
        char * p_out = p_line;

        if( vlc_iconv( priv->text.conv, &p_in, &i_in, &p_out, &i_out ) == VLC_ICONV_ERR )
        {
            msg_Err( s, "conversion error: %s", vlc_strerror_c( errno ) );
            msg_Dbg( s, "original: %zu, in %zu, out %zu", i_line, i_in, i_out );
            /* Reset state */
            size_t r = vlc_iconv( priv->text.conv, NULL, NULL, NULL, NULL );
            VLC_UNUSED( r );
            /* FIXME: the rest of the line is discarded and lost */
        }

        i_line_conv -= i_out;
        p_read = NULL; /* Line already read, only need to advance the stream */
    }

    ssize_t i_data = vlc_stream_Read( s, p_read, i_line );
    assert( i_data > 0 && (size_t) i_data == i_line );
    if( i_data <= 0 )
    {
        /* Hmmm */
        free( p_line );
        return NULL;
    }

    i_line = i_line_conv;

    /* Remove trailing LF/CR */
    while( i_line >= 1 &&
           (p_line[i_line - 1] == '\r' || p_line[i_line - 1] == '\n') )
        i_line--;

    /* Make sure the \0 is there */
    p_line[i_line] = '\0';

    return p_line;
}

static ssize_t vlc_stream_CopyBlock(block_t **restrict pp,
                                    void *buf, size_t len)
{
    block_t *block = *pp;

    if (block == NULL)
        return -1;

    if (len > block->i_buffer)
        len = block->i_buffer;

    if (buf != NULL)
        memcpy(buf, block->p_buffer, len);

    block->p_buffer += len;
    block->i_buffer -= len;

    if (block->i_buffer == 0)
    {
        block_Release(block);
        *pp = NULL;
    }

    return likely(len > 0) ? (ssize_t)len : -1;
}

static ssize_t vlc_stream_ReadRaw(stream_t *s, void *buf, size_t len)
{
    stream_priv_t *priv = stream_priv(s);
    ssize_t ret;

    assert(len <= SSIZE_MAX);

    if (vlc_killed())
        return 0;

    if ((s->ops != NULL && s->ops->stream.read != NULL) || (s->ops == NULL && s->pf_read != NULL))
    {
        assert(priv->block == NULL);
        if (buf == NULL)
        {
            if (unlikely(len == 0))
                return 0;

            char dummy[256];
            ret = (s->ops != NULL ? s->ops->stream.read : s->pf_read)(s, dummy, len <= 256 ? len : 256);
        }
        else
            ret = (s->ops != NULL ? s->ops->stream.read : s->pf_read)(s, buf, len);
        return ret;
    }

    ret = vlc_stream_CopyBlock(&priv->block, buf, len);
    if (ret >= 0)
        return ret;

    if ((s->ops != NULL && s->ops->stream.block != NULL) || (s->ops == NULL && s->pf_block != NULL))
    {
        bool eof = false;

        priv->block = (s->ops != NULL ? s->ops->stream.block : s->pf_block)(s, &eof);
        ret = vlc_stream_CopyBlock(&priv->block, buf, len);
        if (ret >= 0)
            return ret;
        return eof ? 0 : -1;
    }

    return 0;
}

ssize_t vlc_stream_ReadPartial(stream_t *s, void *buf, size_t len)
{
    stream_priv_t *priv = stream_priv(s);
    ssize_t ret;

    ret = vlc_stream_CopyBlock(&priv->peek, buf, len);
    if (ret >= 0)
    {
        priv->offset += ret;
        assert(ret <= (ssize_t)len);
        return ret;
    }

    ret = vlc_stream_ReadRaw(s, buf, len);
    if (ret > 0)
        priv->offset += ret;
    if (ret == 0)
        priv->eof = len != 0;
    assert(ret <= (ssize_t)len);
    return ret;
}

ssize_t vlc_stream_Read(stream_t *s, void *buf, size_t len)
{
    size_t copied = 0;

    while (len > 0)
    {
        ssize_t ret = vlc_stream_ReadPartial(s, buf, len);
        if (ret < 0)
            continue;
        if (ret == 0)
            break;

        if (buf != NULL)
            buf = (char *)buf + ret;
        assert(len >= (size_t)ret);
        len -= ret;
        copied += ret;
    }

    return copied;
}

ssize_t vlc_stream_Peek(stream_t *s, const uint8_t **restrict bufp, size_t len)
{
    stream_priv_t *priv = stream_priv(s);
    block_t *peek;

    peek = priv->peek;
    if (peek == NULL)
    {
        peek = priv->block;
        priv->peek = peek;
        priv->block = NULL;
    }

    if (peek == NULL)
    {
        peek = block_Alloc(len);
        if (unlikely(peek == NULL))
            return VLC_ENOMEM;

        peek->i_buffer = 0;
    }
    else
    if (peek->i_buffer < len)
    {
        size_t avail = peek->i_buffer;

        peek = block_TryRealloc(peek, 0, len);
        if (unlikely(peek == NULL))
            return VLC_ENOMEM;

        peek->i_buffer = avail;
    }

    priv->peek = peek;
    *bufp = peek->p_buffer;

    while (peek->i_buffer < len)
    {
        size_t avail = peek->i_buffer;
        ssize_t ret;

        ret = vlc_stream_ReadRaw(s, peek->p_buffer + avail, len - avail);
        if (ret < 0)
            continue;

        peek->i_buffer += ret;

        if (ret == 0)
            return peek->i_buffer;
    }

    return len;
}

block_t *vlc_stream_ReadBlock(stream_t *s)
{
    stream_priv_t *priv = stream_priv(s);
    block_t *block;

    if (vlc_killed())
    {
        priv->eof = true;
        return NULL;
    }

    if (priv->peek != NULL)
    {
        block = priv->peek;
        priv->peek = NULL;
    }
    else if (priv->block != NULL)
    {
        block = priv->block;
        priv->block = NULL;
    }
    else if ((s->ops != NULL && s->ops->stream.block != NULL) || (s->ops == NULL && s->pf_block != NULL))
    {
        priv->eof = false;
        block = (s->ops != NULL ? s->ops->stream.block : s->pf_block)(s, &priv->eof);
    }
    else
    {
        block = block_Alloc(4096);
        if (unlikely(block == NULL))
            return NULL;

        ssize_t ret = (s->ops != NULL ? s->ops->stream.read : s->pf_read)(s, block->p_buffer, block->i_buffer);
        if (ret > 0)
            block->i_buffer = ret;
        else
        {
            block_Release(block);
            block = NULL;
        }

        priv->eof = !ret;
    }

    if (block != NULL)
        priv->offset += block->i_buffer;

    return block;
}

uint64_t vlc_stream_Tell(const stream_t *s)
{
    const stream_priv_t *priv = stream_priv(s);

    return priv->offset;
}

bool vlc_stream_Eof(const stream_t *s)
{
    const stream_priv_t *priv = stream_priv(s);

    return priv->eof;
}

int vlc_stream_Seek(stream_t *s, uint64_t offset)
{
    stream_priv_t *priv = stream_priv(s);

    priv->eof = false;

    block_t *peek = priv->peek;
    if (peek != NULL)
    {
        if (offset >= priv->offset
         && offset <= (priv->offset + peek->i_buffer))
        {   /* Seeking within the peek buffer */
            size_t fwd = offset - priv->offset;

            peek->p_buffer += fwd;
            peek->i_buffer -= fwd;
            priv->offset = offset;

            if (peek->i_buffer == 0)
            {
                priv->peek = NULL;
                block_Release(peek);
            }

            return VLC_SUCCESS;
        }
    }
    else
    {
        if (priv->offset == offset)
            return VLC_SUCCESS; /* Nothing to do! */
    }

    int ret;
    if (s->ops == NULL && s->pf_seek != NULL) {
        ret = s->pf_seek(s, offset);
    } else if (s->ops != NULL && s->ops->stream.seek != NULL) {
        ret = s->ops->stream.seek(s, offset);
    } else {
        return VLC_EGENERIC;
    }

    if (ret != VLC_SUCCESS)
        return ret;

    priv->offset = offset;

    if (peek != NULL)
    {
        priv->peek = NULL;
        block_Release(peek);
    }

    if (priv->block != NULL)
    {
        block_Release(priv->block);
        priv->block = NULL;
    }

    return VLC_SUCCESS;
}

/**
 * Use to control the "stream_t *". Look at #stream_query_e for
 * possible "i_query" value and format arguments.  Return VLC_SUCCESS
 * if ... succeed ;) and VLC_EGENERIC if failed or unimplemented
 */
int vlc_stream_vaControl(stream_t *s, int cmd, va_list args)
{
    stream_priv_t *priv = stream_priv(s);

    switch (cmd)
    {
        case STREAM_SET_TITLE:
        case STREAM_SET_SEEKPOINT:
        {
            int ret;

            if (s->ops != NULL && cmd == STREAM_SET_TITLE) {
                int title = va_arg(args, int);
                ret = s->ops->set_title(s, title);
            } else if (s->ops != NULL && cmd == STREAM_SET_SEEKPOINT) {
                int seekpoint = va_arg(args, int);
                ret = s->ops->set_seek_point(s, seekpoint);
            } else {
                ret = s->pf_control(s, cmd, args);
            }

            if (ret != VLC_SUCCESS)
                return ret;

            priv->offset = 0;

            if (priv->peek != NULL)
            {
                block_Release(priv->peek);
                priv->peek = NULL;
            }

            if (priv->block != NULL)
            {
                block_Release(priv->block);
                priv->block = NULL;
            }

            return VLC_SUCCESS;
        }
    }

    if (s->ops == NULL)
        return s->pf_control(s, cmd, args);

    switch (cmd) {
        case STREAM_CAN_SEEK:
        {
            bool *can_seek = va_arg(args, bool *);
            if (s->ops->can_seek != NULL) {
                *can_seek = s->ops->can_seek(s);
            } else {
                *can_seek = false;
            }
            return VLC_SUCCESS;
        }
        case STREAM_CAN_FASTSEEK:
        {
            bool *can_fastseek = va_arg(args, bool *);
            if (s->ops->stream.can_fastseek != NULL) {
                *can_fastseek = s->ops->stream.can_fastseek(s);
            } else {
                *can_fastseek = false;
            }
            return VLC_SUCCESS;
        }
        case STREAM_CAN_PAUSE:
        {
            bool *can_pause = va_arg(args, bool *);
            if (s->ops->can_pause != NULL) {
                *can_pause = s->ops->can_pause(s);
            } else {
                *can_pause = false;
            }
            return VLC_SUCCESS;
        }
        case STREAM_CAN_CONTROL_PACE:
        {
            bool *can_control_pace = va_arg(args, bool *);
            if (s->ops->can_control_pace != NULL) {
                *can_control_pace = s->ops->can_control_pace(s);
            } else {
                *can_control_pace = false;
            }
            return VLC_SUCCESS;
        }
        case STREAM_GET_SIZE:
            if (s->ops->stream.get_size != NULL) {
                uint64_t *size = va_arg(args, uint64_t *);
                return s->ops->stream.get_size(s, size);
            }
            return VLC_EGENERIC;
        case STREAM_GET_PTS_DELAY:
            if (s->ops->get_pts_delay != NULL) {
                vlc_tick_t *pts_delay = va_arg(args, vlc_tick_t *);
                return s->ops->get_pts_delay(s, pts_delay);
            }
            return VLC_EGENERIC;
        case STREAM_GET_TITLE_INFO:
            if (s->ops->stream.get_title_info != NULL) {
                input_title_t ***title_info = va_arg(args, input_title_t ***);
                int *unk = va_arg(args, int *);
                return s->ops->stream.get_title_info(s, title_info, unk);
            }
            return VLC_EGENERIC;
        case STREAM_GET_TITLE:
            if (s->ops->stream.get_title != NULL) {
                unsigned *title = va_arg(args, unsigned *);
                return s->ops->stream.get_title(s, title);
            }
            return VLC_EGENERIC;
        case STREAM_GET_SEEKPOINT:
            if (s->ops->stream.get_seekpoint != NULL) {
                unsigned *seekpoint = va_arg(args, unsigned *);
                return s->ops->stream.get_seekpoint(s, seekpoint);
            }
            return VLC_EGENERIC;
        case STREAM_GET_META:
            if (s->ops->get_meta != NULL) {
                vlc_meta_t *meta = va_arg(args, vlc_meta_t *);
                return s->ops->get_meta(s, meta);
            }
            return VLC_EGENERIC;
        case STREAM_GET_CONTENT_TYPE:
            if (s->ops->stream.get_content_type != NULL) {
                char **content_type = va_arg(args, char **);
                return s->ops->stream.get_content_type(s, content_type);
            }
            return VLC_EGENERIC;
        case STREAM_GET_SIGNAL:
            if (s->ops->get_signal != NULL) {
                double *quality = va_arg(args, double *);
                double *strength = va_arg(args, double *);
                return s->ops->get_signal(s, quality, strength);
            }
            return VLC_EGENERIC;
        case STREAM_GET_TAGS:
            if (s->ops->stream.get_tags != NULL) {
                const block_t **block = va_arg(args, const block_t **);
                return s->ops->stream.get_tags(s, block);
            }
            return VLC_EGENERIC;
        case STREAM_GET_TYPE:
            if (s->ops->get_type != NULL) {
                int *type = va_arg(args, int *);
                return s->ops->get_type(s, type);
            }
            return VLC_EGENERIC;
        case STREAM_GET_PRIVATE_ID_STATE:
            if (s->ops->stream.get_private_id_state != NULL) {
                int priv_data = va_arg(args, int);
                bool *selected = va_arg(args, bool *);
                return s->ops->stream.get_private_id_state(s, priv_data, selected);
            }
            return VLC_EGENERIC;
        case STREAM_SET_PAUSE_STATE:
            if (s->ops->set_pause_state != NULL) {
                bool pause_state = (bool)va_arg(args, int);
                return s->ops->set_pause_state(s, pause_state);
            }
            return VLC_EGENERIC;
        case STREAM_SET_RECORD_STATE:
            if (s->ops->stream.set_record_state != NULL) {
                bool record_state = (bool)va_arg(args, int);
                const char *dir_path = NULL;
                const char *ext = NULL;
                if (record_state) {
                    dir_path = va_arg(args, const char *);
                    ext = va_arg(args, const char *);
                }
                return s->ops->stream.set_record_state(s, record_state, dir_path, ext);
            }
            return VLC_EGENERIC;
        case STREAM_SET_PRIVATE_ID_STATE:
            if (s->ops->stream.set_private_id_state != NULL) {
                int priv_data = va_arg(args, int);
                bool selected = (bool)va_arg(args, int);
                return s->ops->stream.set_private_id_state(s, priv_data, selected);
            }
            return VLC_EGENERIC;
        case STREAM_SET_PRIVATE_ID_CA:
            if (s->ops->stream.set_private_id_ca != NULL) {
                void *payload = va_arg(args, void *);
                return s->ops->stream.set_private_id_ca(s, payload);
            }
            return VLC_EGENERIC;
        default:
            vlc_assert_unreachable();
    }
}

/**
 * Read data into a block.
 *
 * @param s stream to read data from
 * @param size number of bytes to read
 * @return a block of data, or NULL on error
 @ note The block size may be shorter than requested if the end-of-stream was
 * reached.
 */
block_t *vlc_stream_Block( stream_t *s, size_t size )
{
    if( unlikely(size > SSIZE_MAX) )
        return NULL;

    block_t *block = block_Alloc( size );
    if( unlikely(block == NULL) )
        return NULL;

    ssize_t val = vlc_stream_Read( s, block->p_buffer, size );
    if( val <= 0 )
    {
        block_Release( block );
        return NULL;
    }

    block->i_buffer = val;
    return block;
}

int vlc_stream_ReadDir( stream_t *s, input_item_node_t *p_node )
{
    assert(s->pf_readdir != NULL || (s->ops != NULL && s->ops->stream.readdir != NULL));
    return (s->ops != NULL ? s->ops->stream.readdir : s->pf_readdir)( s, p_node );
}