path: root/src/plugins/vlc_extractor.c

/*
     This file is part of libextractor.
     Copyright (C) 2021 Christian Grothoff

     libextractor 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 3, or (at your
     option) any later version.

     libextractor 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 libextractor; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.

THIS PLUGIN IS NOT WORKING, see #2075!

*/
/**
 * @file plugins/vlc_extractor.c
 * @brief plugin to extract metadata using libvlc
 * @author Christian Grothoff
 */
#include "platform.h"
#include "extractor.h"
#include <vlc/vlc.h>
#include <signal.h>

/**
 * Function to help VLC open a custom bitstream input media.
 *
 * The same media item can be opened multiple times. Each time, this callback
 * is invoked. It should allocate and initialize any instance-specific
 * resources, then store them in *datap. The instance resources can be freed
 * in the @ref libvlc_media_close_cb callback.
 *
 * @param opaque our `struct EXTRACTOR_ExtractContext`
 * @param[out] datap storage space for a private data pointer
 * @param[out] sizep byte length of the bitstream or UINT64_MAX if unknown
 *
 * @note For convenience, *datap is initially NULL and *sizep is initially 0.
 *
 * @return 0 on success, non-zero on error. In case of failure, the other
 * callbacks will not be invoked and any value stored in *datap and *sizep is
 * discarded.
 */
static int
open_cb (void *opaque,
         void **datap,
         uint64_t *sizep)
{
  struct EXTRACTOR_ExtractContext *ec = opaque;

  *datap = ec;
  *sizep = ec->get_size (ec->cls);
  if (UINT64_MAX == *sizep)
  {
    fprintf (stderr,
             "Open failed!\n");
    return 1;
  }
  fprintf (stderr,
           "Open returns %llu file size!\n",
           (unsigned long long) *sizep);
  return 0;
}


/**
 * Function to help VLC read data from a custom bitstream input media.
 *
 * @param opaque our `struct EXTRACTOR_ExtractContext`
 * @param buf start address of the buffer to read data into
 * @param len bytes length of the buffer
 * @return strictly positive number of bytes read, 0 on end-of-stream,
 *         or -1 on non-recoverable error
 *
 * @note If no data is immediately available, then the callback should sleep.
 * @warning The application is responsible for avoiding deadlock situations.
 * In particular, the callback should return an error if playback is stopped;
 * if it does not return, then libvlc_media_player_stop() will never return.
 */
static ssize_t
read_cb (void *opaque,
         unsigned char *buf,
         size_t len)
{
  struct EXTRACTOR_ExtractContext *ec = opaque;
  void *data;
  ssize_t ret;

  ret = ec->read (ec->cls,
                  &data,
                  len);
  if (-1 == ret)
  {
    fprintf (stderr,
             "Read failed!\n");
    return -1;
  }
  memcpy (buf,
          data,
          ret);
  fprintf (stderr,
           "Read %u bytes!\n",
           (unsigned int) ret);
  return ret;
}


/**
 * Allow VLC to seek a custom bitstream input media.
 *
 * @param opaque our `struct EXTRACTOR_ExtractContext`
 * @param offset absolute byte offset to seek to
 * @return 0 on success, -1 on error.
 */
static int
seek_cb (void *opaque,
         uint64_t offset)
{
  struct EXTRACTOR_ExtractContext *ec = opaque;

  fprintf (stderr,
           "Seek to %llu!\n",
           (unsigned long long) offset);
  if (offset > INT64_MAX)
  {
    fprintf (stderr,
             "Excessive seek, impossible with LE!\n");
    return -1;
  }
  if (-1 ==
      ec->seek (ec->cls,
                offset,
                SEEK_SET))
  {
    fprintf (stderr,
             "Seek failed!\n");
    return -1;
  }
  return 0;
}


/**
 * Callback prototype to close a custom bitstream input media.
 *
 * @param opaque our `struct EXTRACTOR_ExtractContext`
 */
static void
close_cb (void *opaque)
{
  /* intentionally empty */
  fprintf (stderr,
           "Close called\n");
}


static void
extract (struct EXTRACTOR_ExtractContext *ec,
         libvlc_media_t *media)
{
  struct
  {
    enum libvlc_meta_t vt;
    enum EXTRACTOR_MetaType mt;
  } map[] = {
    { libvlc_meta_Title,
      EXTRACTOR_METATYPE_TITLE },
    { libvlc_meta_Artist,
      EXTRACTOR_METATYPE_ARTIST },
    { libvlc_meta_Genre,
      EXTRACTOR_METATYPE_GENRE },
    { libvlc_meta_Copyright,
      EXTRACTOR_METATYPE_COPYRIGHT },
    { libvlc_meta_Album,
      EXTRACTOR_METATYPE_ALBUM },
    { libvlc_meta_TrackNumber,
      EXTRACTOR_METATYPE_TRACK_NUMBER },
    { libvlc_meta_Description,
      EXTRACTOR_METATYPE_DESCRIPTION },
    { libvlc_meta_Rating,
      EXTRACTOR_METATYPE_RATING },
    { libvlc_meta_Date,
      EXTRACTOR_METATYPE_CREATION_TIME },
    { libvlc_meta_Setting,
      EXTRACTOR_METATYPE_UNKNOWN },
    { libvlc_meta_URL,
      EXTRACTOR_METATYPE_URL },
    { libvlc_meta_Language,
      EXTRACTOR_METATYPE_LANGUAGE },
    { libvlc_meta_NowPlaying,
      EXTRACTOR_METATYPE_UNKNOWN },
    { libvlc_meta_Publisher,
      EXTRACTOR_METATYPE_PUBLISHER },
    { libvlc_meta_EncodedBy,
      EXTRACTOR_METATYPE_ENCODED_BY },
    { libvlc_meta_ArtworkURL,
      EXTRACTOR_METATYPE_URL },
    { libvlc_meta_TrackID,
      EXTRACTOR_METATYPE_TRACK_NUMBER },
    { libvlc_meta_TrackTotal,
      EXTRACTOR_METATYPE_UNKNOWN },
    { libvlc_meta_Director,
      EXTRACTOR_METATYPE_MOVIE_DIRECTOR },
    { libvlc_meta_Season,
      EXTRACTOR_METATYPE_SHOW_SEASON_NUMBER },
    { libvlc_meta_Episode,
      EXTRACTOR_METATYPE_SHOW_EPISODE_NUMBER },
    { libvlc_meta_ShowName,
      EXTRACTOR_METATYPE_SHOW_NAME },
    { libvlc_meta_Actors,
      EXTRACTOR_METATYPE_PERFORMER },
    { libvlc_meta_AlbumArtist,
      EXTRACTOR_METATYPE_ARTIST },
    { libvlc_meta_DiscNumber,
      EXTRACTOR_METATYPE_DISC_NUMBER },
    { libvlc_meta_DiscTotal,
      EXTRACTOR_METATYPE_UNKNOWN },
    { 0, 0 }
  };

  for (unsigned int i = 0;
       EXTRACTOR_METATYPE_RESERVED != map[i].mt;
       i++)
  {
    char *meta;

    fprintf (stderr,
             ".");
    meta = libvlc_media_get_meta (media,
                                  map[i].vt);
    if (NULL == meta)
      continue;
    ec->proc (ec->cls,
              "vlc",
              map[i].mt,
              EXTRACTOR_METAFORMAT_UTF8, /* ??? */
              "text/plain",
              meta,
              strlen (meta) + 1);
    free (meta);
  }
}


static void
media_ready (const struct libvlc_event_t *p_event,
             void *p_data)
{
  fprintf (stderr,
           "media status: %d, %d\n",
           p_event->type == libvlc_MediaParsedChanged,
           p_event->u.media_parsed_changed.new_status);
  if (p_event->u.media_parsed_changed.new_status ==
      libvlc_media_parsed_status_done)
  {
    fprintf (stderr,
             "media ready\n");
  }
}


static void
my_logger (void *data,
           int level,
           const libvlc_log_t *ctx,
           const char *fmt,
           va_list args)
{
  vfprintf (stderr,
            fmt,
            args);
  fprintf (stderr, "\n");
}


/**
 * Extract information using libvlc
 *
 * @param ec extraction context
 */
void
EXTRACTOR_vlc_extract_method (struct EXTRACTOR_ExtractContext *ec)
{
  libvlc_instance_t *vlc;
  libvlc_media_t *media;
  libvlc_event_manager_t *em;

  {
    sigset_t set;

    signal (SIGCHLD, SIG_DFL);
    sigemptyset (&set);
    sigaddset (&set, SIGPIPE);
    pthread_sigmask (SIG_BLOCK, &set, NULL);
  }

  {
    const char *argv[] = {
      "-v",
      "3",
      NULL
    };
    vlc = libvlc_new (2, argv);
  }
  if (NULL == vlc)
    return;
  libvlc_log_set (vlc,
                  &my_logger,
                  NULL);
  if (1)
  {
    fprintf (stderr,
             "Opening file `%s'\n",
             "testdata/matroska_flame.mkv");
    media = libvlc_media_new_path (vlc,
                                   "testdata/matroska_flame.mkv");
    if (NULL == media)
    {
      fprintf (stderr,
               "Open failed\n");
      libvlc_release (vlc);
      return;
    }
  }
  else if (0)
  {
    fprintf (stderr,
             "Opening file `%s'\n",
             "testdata/matroska_flame.mkv");
    int fd = open ("testdata/matroska_flame.mkv",
                   O_RDONLY);
    if (-1 == fd)
    {
      fprintf (stderr,
               "Open failed: %s\n",
               strerror (errno));
      libvlc_release (vlc);
      return;
    }
    media = libvlc_media_new_fd (vlc,
                                 fd);
  }
  else if (0)
  {
    fprintf (stderr,
             "Reading via IPC\n");
    media = libvlc_media_new_callbacks (vlc,
                                        &open_cb,
                                        &read_cb,
                                        &seek_cb,
                                        &close_cb,
                                        ec);
  }
  else
    abort ();
  if (NULL == media)
  {
    libvlc_release (vlc);
    return;
  }

  em = libvlc_media_event_manager (media);
  libvlc_event_attach (em,
                       libvlc_MediaParsedChanged,
                       &media_ready,
                       ec);
  fprintf (stderr,
           "Triggering parser\n");
  {
    int status;

    status = libvlc_media_parse_with_options (media,
                                              libvlc_media_fetch_local
                                              | libvlc_media_parse_network
                                              | libvlc_media_fetch_network,
                                              30000); /* 30s timeout */
    fprintf (stderr,
             "Status: %d\n",
             status);
  }
  fprintf (stderr,
           "Sleeping\n");
  sleep (10);
  extract (ec,
           media);
  libvlc_media_release (media);
  libvlc_release (vlc);
}


/* end of vlc_extractor.c */