gstreamer/gst/xdgmime/gstxdgmime.c

/* GStreamer
 * Copyright (C) <2009> Sebastian Dröge <sebastian.droege@collabora.co.uk>
 *
 * 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.h>
#include "xdgmime/xdgmime.h"

GST_DEBUG_CATEGORY (xdgmime_debug);
#define GST_CAT_DEFAULT xdgmime_debug

G_LOCK_DEFINE_STATIC (xdg_lock);

static void
xdgmime_typefind (GstTypeFind * find, gpointer user_data)
{
  const gchar *mimetype;
  gsize length = 16384;
  guint64 tf_length;
  gint prio;
  guint8 *data;

  if ((tf_length = gst_type_find_get_length (find)) > 0)
    length = MIN (length, tf_length);

  if ((data = gst_type_find_peek (find, 0, length)) == NULL)
    return;

  /* FIXME: xdg-mime is not thread-safe as it stores the cache globally
   * and updates it from every call if changes were done without
   * any locking
   */
  G_LOCK (xdg_lock);
  mimetype = xdg_mime_get_mime_type_for_data (data, length, &prio);
  G_UNLOCK (xdg_lock);

  if (mimetype == NULL || g_str_equal (mimetype, XDG_MIME_TYPE_UNKNOWN))
    return;

  GST_DEBUG ("Got mimetype '%s' with prio %d", mimetype, prio);

  /* Ignore audio/video types:
   *  - our own typefinders in -base are likely to be better at this
   *    (and if they're not, we really want to fix them, that's why we don't
   *    report xdg-detected audio/video types at all, not even with a low
   *    probability)
   *  - we want to detect GStreamer media types and not MIME types
   *  - the purpose of this xdg mime finder is mainly to prevent false
   *    positives of non-media formats, not to typefind audio/video formats */
  if (g_str_has_prefix (mimetype, "audio/") ||
      g_str_has_prefix (mimetype, "video/")) {
    GST_LOG ("Ignoring audio/video mime type");
    return;
  }

  /* Again, we mainly want the xdg typefinding to prevent false-positives on
   * non-media formats, so suggest the type with a probability that trumps
   * uncertain results of our typefinders, but not more than that. */
  GST_LOG ("Suggesting '%s' with probability POSSIBLE", mimetype);
  gst_type_find_suggest_simple (find, GST_TYPE_FIND_POSSIBLE, mimetype, NULL);
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  GstCaps *caps = NULL;
  guint major, minor, micro, nano;
  gboolean ret;

  /* FIXME: GStreamer before 0.10.22.1 produced assertions
   * when storing typefind factories with NULL caps */
  gst_version (&major, &minor, &micro, &nano);
  if (major <= 0 && minor <= 10 && micro <= 22 && nano <= 0)
    caps = gst_caps_new_empty ();

  GST_DEBUG_CATEGORY_INIT (xdgmime_debug, "xdgmime", 0, "XDG-MIME");

  ret = gst_type_find_register (plugin,
      "xdgmime", GST_RANK_MARGINAL, xdgmime_typefind, NULL, caps, NULL, NULL);

  if (caps)
    gst_caps_unref (caps);

  return ret;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "xdgmime",
    "XDG-MIME",
    plugin_init, VERSION, "LGPL", GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)