gstreamer/gst-libs/gst/tag/tags.c

/* GStreamer non-core tag registration and tag utility functions
 * Copyright (C) 2005 Ross Burton <ross@burtonini.com>
 * Copyright (C) 2006 Tim-Philipp Müller <tim centricular net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library 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.
 */

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

#include <gst/gst-i18n-plugin.h>
#include <gst/gst.h>
#include "tag.h"

#include <string.h>

/**
 * SECTION:gsttag
 * @short_description: additional tag definitions for plugins and applications
 * @see_also: #GstTagList
 * 
 * <refsect2>
 * <para>
 * Contains additional standardized GStreamer tag definitions for plugins
 * and applications, and functions to register them with the GStreamer
 * tag system.
 * </para>
 * </refsect2>
 */


static gpointer
gst_tag_register_tags_internal (gpointer unused)
{
#ifdef ENABLE_NLS
  GST_DEBUG ("binding text domain %s to locale dir %s", GETTEXT_PACKAGE,
      LOCALEDIR);
  bindtextdomain (GETTEXT_PACKAGE, LOCALEDIR);
#endif

  /* musicbrainz tags */
  gst_tag_register (GST_TAG_MUSICBRAINZ_TRACKID, GST_TAG_FLAG_META,
      G_TYPE_STRING, _("track ID"), _("MusicBrainz track ID"), NULL);
  gst_tag_register (GST_TAG_MUSICBRAINZ_ARTISTID, GST_TAG_FLAG_META,
      G_TYPE_STRING, _("artist ID"), _("MusicBrainz artist ID"), NULL);
  gst_tag_register (GST_TAG_MUSICBRAINZ_ALBUMID, GST_TAG_FLAG_META,
      G_TYPE_STRING, _("album ID"), _("MusicBrainz album ID"), NULL);
  gst_tag_register (GST_TAG_MUSICBRAINZ_ALBUMARTISTID, GST_TAG_FLAG_META,
      G_TYPE_STRING,
      _("album artist ID"), _("MusicBrainz album artist ID"), NULL);
  gst_tag_register (GST_TAG_MUSICBRAINZ_TRMID, GST_TAG_FLAG_META,
      G_TYPE_STRING, _("track TRM ID"), _("MusicBrainz TRM ID"), NULL);

  /* CDDA tags */
  gst_tag_register (GST_TAG_CDDA_CDDB_DISCID, GST_TAG_FLAG_META,
      G_TYPE_STRING, "discid", "CDDB discid for metadata retrieval",
      gst_tag_merge_use_first);

  gst_tag_register (GST_TAG_CDDA_CDDB_DISCID_FULL, GST_TAG_FLAG_META,
      G_TYPE_STRING, "discid full",
      "CDDB discid for metadata retrieval (full)", gst_tag_merge_use_first);

  gst_tag_register (GST_TAG_CDDA_MUSICBRAINZ_DISCID, GST_TAG_FLAG_META,
      G_TYPE_STRING, "musicbrainz-discid",
      "Musicbrainz discid for metadata retrieval", gst_tag_merge_use_first);

  gst_tag_register (GST_TAG_CDDA_MUSICBRAINZ_DISCID_FULL, GST_TAG_FLAG_META,
      G_TYPE_STRING, "musicbrainz-discid-full",
      "Musicbrainz discid for metadata retrieval (full)",
      gst_tag_merge_use_first);

  return NULL;
}

/* FIXME 0.11: rename this to gst_tag_init() or gst_tag_register_tags() */
/**
 * gst_tag_register_musicbrainz_tags
 *
 * Registers additional musicbrainz-specific tags with the GStreamer tag
 * system. Plugins and applications that use these tags should call this
 * function before using them. Can be called multiple times.
 */
void
gst_tag_register_musicbrainz_tags (void)
{
  static GOnce mb_once = G_ONCE_INIT;

  g_once (&mb_once, gst_tag_register_tags_internal, NULL);
}

static void
register_tag_image_type_enum (GType * id)
{
  static const GEnumValue image_types[] = {
    {GST_TAG_IMAGE_TYPE_UNDEFINED, "GST_TAG_IMAGE_TYPE_UNDEFINED", "undefined"},
    {GST_TAG_IMAGE_TYPE_FRONT_COVER, "GST_TAG_IMAGE_TYPE_FRONT_COVER",
        "front-cover"},
    {GST_TAG_IMAGE_TYPE_BACK_COVER, "GST_TAG_IMAGE_TYPE_BACK_COVER",
        "back-cover"},
    {GST_TAG_IMAGE_TYPE_LEAFLET_PAGE, "GST_TAG_IMAGE_TYPE_LEAFLET_PAGE",
        "leaflet-page"},
    {GST_TAG_IMAGE_TYPE_MEDIUM, "GST_TAG_IMAGE_TYPE_MEDIUM", "medium"},
    {GST_TAG_IMAGE_TYPE_LEAD_ARTIST, "GST_TAG_IMAGE_TYPE_LEAD_ARTIST",
        "lead-artist"},
    {GST_TAG_IMAGE_TYPE_ARTIST, "GST_TAG_IMAGE_TYPE_ARTIST", "artist"},
    {GST_TAG_IMAGE_TYPE_CONDUCTOR, "GST_TAG_IMAGE_TYPE_CONDUCTOR", "conductor"},
    {GST_TAG_IMAGE_TYPE_BAND_ORCHESTRA, "GST_TAG_IMAGE_TYPE_BAND_ORCHESTRA",
        "band-orchestra"},
    {GST_TAG_IMAGE_TYPE_COMPOSER, "GST_TAG_IMAGE_TYPE_COMPOSER", "composer"},
    {GST_TAG_IMAGE_TYPE_LYRICIST, "GST_TAG_IMAGE_TYPE_LYRICIST", "lyricist"},
    {GST_TAG_IMAGE_TYPE_RECORDING_LOCATION,
          "GST_TAG_IMAGE_TYPE_RECORDING_LOCATION",
        "recording-location"},
    {GST_TAG_IMAGE_TYPE_DURING_RECORDING, "GST_TAG_IMAGE_TYPE_DURING_RECORDING",
        "during-recording"},
    {GST_TAG_IMAGE_TYPE_DURING_PERFORMANCE,
          "GST_TAG_IMAGE_TYPE_DURING_PERFORMANCE",
        "during-performance"},
    {GST_TAG_IMAGE_TYPE_VIDEO_CAPTURE, "GST_TAG_IMAGE_TYPE_VIDEO_CAPTURE",
        "video-capture"},
    {GST_TAG_IMAGE_TYPE_FISH, "GST_TAG_IMAGE_TYPE_FISH", "fish"},
    {GST_TAG_IMAGE_TYPE_ILLUSTRATION, "GST_TAG_IMAGE_TYPE_ILLUSTRATION",
        "illustration"},
    {GST_TAG_IMAGE_TYPE_BAND_ARTIST_LOGO, "GST_TAG_IMAGE_TYPE_BAND_ARTIST_LOGO",
        "artist-logo"},
    {GST_TAG_IMAGE_TYPE_PUBLISHER_STUDIO_LOGO,
          "GST_TAG_IMAGE_TYPE_PUBLISHER_STUDIO_LOGO",
        "publisher-studio-logo"},
    {0, NULL, NULL}
  };

  *id = g_enum_register_static ("GstTagImageType", image_types);
}

GType
gst_tag_image_type_get_type (void)
{
  static GType id;
  static GOnce once = G_ONCE_INIT;

  g_once (&once, (GThreadFunc) register_tag_image_type_enum, &id);
  return id;
}

/**
 * gst_tag_parse_extended_comment:
 * @ext_comment: an extended comment string, see #GST_TAG_EXTENDED_COMMENT
 * @key: return location for the comment description key, or NULL
 * @lang: return location for the comment ISO-639 language code, or NULL
 * @value: return location for the actual comment string, or NULL
 * @fail_if_no_key: whether to fail if strings are not in key=value form
 *
 * Convenience function to parse a GST_TAG_EXTENDED_COMMENT string and
 * separate it into its components.
 *
 * If successful, @key, @lang and/or @value will be set to newly allocated
 * strings that you need to free with g_free() when done. @key and @lang
 * may also be set to NULL by this function if there is no key or no language
 * code in the extended comment string.
 *
 * Returns: TRUE if the string could be parsed, otherwise FALSE
 *
 * Since: 0.10.10
 */
gboolean
gst_tag_parse_extended_comment (const gchar * ext_comment, gchar ** key,
    gchar ** lang, gchar ** value, gboolean fail_if_no_key)
{
  const gchar *div, *bop, *bcl;

  g_return_val_if_fail (ext_comment != NULL, FALSE);
  g_return_val_if_fail (g_utf8_validate (ext_comment, -1, NULL), FALSE);

  if (key)
    *key = NULL;
  if (lang)
    *lang = NULL;

  div = strchr (ext_comment, '=');
  bop = strchr (ext_comment, '[');
  bcl = strchr (ext_comment, ']');

  if (div == NULL) {
    if (fail_if_no_key)
      return FALSE;
    if (value)
      *value = g_strdup (ext_comment);
    return TRUE;
  }

  if (bop != NULL && bop < div) {
    if (bcl < bop || bcl > div)
      return FALSE;
    if (key)
      *key = g_strndup (ext_comment, bop - ext_comment);
    if (lang)
      *lang = g_strndup (bop + 1, bcl - bop - 1);
  } else {
    if (key)
      *key = g_strndup (ext_comment, div - ext_comment);
  }

  if (value)
    *value = g_strdup (div + 1);

  return TRUE;
}

/**
 * gst_tag_freeform_string_to_utf8:
 * @data: string data
 * @size: length of string data, or -1 if the string is NUL-terminated
 * @env_vars: a NULL-terminated string array of environment variable names,
 *            or NULL
 *
 * Convenience function to read a string with unknown character encoding. If
 * the string is already in UTF-8 encoding, it will be returned right away.
 * Otherwise, the environment will be searched for a number of environment
 * variables (whose names are specified in the NULL-terminated string array
 * @env_vars) containing a list of character encodings to try/use. If none
 * are specified, the current locale will be tried. If that also doesn't work,
 * ISO-8859-1 is assumed (which will almost always succeed).
 *
 * Returns: a newly-allocated string in UTF-8 encoding, or NULL
 *
 * Since: 0.10.13
 */
gchar *
gst_tag_freeform_string_to_utf8 (const gchar * data, gint size,
    const gchar ** env_vars)
{
  const gchar *cur_loc = NULL;
  gsize bytes_read;
  gchar *utf8 = NULL;

  g_return_val_if_fail (data != NULL, NULL);

  if (size < 0)
    size = strlen (data);

  /* chop off trailing string terminators to make sure utf8_validate doesn't
   * get to see them (since that would make the utf8 check fail) */
  while (size > 0 && data[size - 1] == '\0')
    --size;

  /* Should we try the charsets specified
   * via environment variables FIRST ? */
  if (g_utf8_validate (data, size, NULL)) {
    utf8 = g_strndup (data, size);
    GST_LOG ("String '%s' is valid UTF-8 already", utf8);
    goto beach;
  }

  while (env_vars && *env_vars != NULL) {
    const gchar *env = NULL;

    /* Try charsets specified via the environment */
    env = g_getenv (*env_vars);
    if (env != NULL && *env != '\0') {
      gchar **c, **csets;

      csets = g_strsplit (env, G_SEARCHPATH_SEPARATOR_S, -1);

      for (c = csets; c && *c; ++c) {
        GST_LOG ("Trying to convert freeform string to UTF-8 from '%s'", *c);
        if ((utf8 =
                g_convert (data, size, "UTF-8", *c, &bytes_read, NULL, NULL))) {
          if (bytes_read == size) {
            g_strfreev (csets);
            goto beach;
          }
          g_free (utf8);
          utf8 = NULL;
        }
      }

      g_strfreev (csets);
    }
    ++env_vars;
  }

  /* Try current locale (if not UTF-8) */
  if (!g_get_charset (&cur_loc)) {
    GST_LOG ("Trying to convert freeform string using locale ('%s')", cur_loc);
    if ((utf8 = g_locale_to_utf8 (data, size, &bytes_read, NULL, NULL))) {
      if (bytes_read == size) {
        goto beach;
      }
      g_free (utf8);
      utf8 = NULL;
    }
  }

  /* Try ISO-8859-1 */
  GST_LOG ("Trying to convert freeform string using ISO-8859-1 fallback");
  utf8 = g_convert (data, size, "UTF-8", "ISO-8859-1", &bytes_read, NULL, NULL);
  if (utf8 != NULL && bytes_read == size) {
    goto beach;
  }

  g_free (utf8);
  return NULL;

beach:

  g_strchomp (utf8);
  if (utf8 && utf8[0] != '\0') {
    GST_LOG ("Returning '%s'", utf8);
    return utf8;
  }

  g_free (utf8);
  return NULL;
}