gstreamer/gst/gsttypefind.c

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *
 * gsttypefind.c: 
 *
 * 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.
 */


#include "gst_private.h"
#include "gsttype.h"
#include "gstinfo.h"
#include "gsttypefind.h"

GstElementDetails gst_type_find_details = {
  "TypeFind",
  "Generic",
  "LGPL",
  "Finds the media type of a stream",
  VERSION,
  "Erik Walthinsen <omega@cse.ogi.edu>,"
  "Wim Taymans <wim.taymans@chello.be>",
  "(C) 1999",
};

/* generic templates */
GST_PAD_TEMPLATE_FACTORY (type_find_sink_factory,
  "sink",
  GST_PAD_SINK,
  GST_PAD_ALWAYS,
  NULL
);

/* TypeFind signals and args */
enum {
  HAVE_TYPE,
  LAST_SIGNAL
};

enum {
  ARG_0,
  ARG_CAPS,
};


static void	gst_type_find_class_init	(GstTypeFindClass *klass);
static void	gst_type_find_init		(GstTypeFind *typefind);

static void	gst_type_find_set_property	(GObject *object, guint prop_id,
						 const GValue *value, 
						 GParamSpec *pspec);
static void	gst_type_find_get_property	(GObject *object, guint prop_id,
						 GValue *value, 
						 GParamSpec *pspec);

static void	gst_type_find_loopfunc		(GstElement *element);
static GstElementStateReturn
		gst_type_find_change_state 	(GstElement *element);

static GstElementClass *parent_class = NULL;
static guint gst_type_find_signals[LAST_SIGNAL] = { 0 };

GType
gst_type_find_get_type (void)
{
  static GType typefind_type = 0;

  if (!typefind_type) {
    static const GTypeInfo typefind_info = {
      sizeof(GstTypeFindClass),
      NULL,
      NULL,
      (GClassInitFunc)gst_type_find_class_init,
      NULL,
      NULL,
      sizeof(GstTypeFind),
      0,
      (GInstanceInitFunc)gst_type_find_init,
      NULL
    };
    typefind_type = g_type_register_static (GST_TYPE_ELEMENT,
					    "GstTypeFind",
					    &typefind_info, 0);
  }
  return typefind_type;
}

static void
gst_type_find_class_init (GstTypeFindClass *klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass*)klass;
  gstelement_class = (GstElementClass*)klass;

  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_CAPS,
    g_param_spec_pointer ("caps", "Caps", "Found capabilities", G_PARAM_READABLE));

  gst_type_find_signals[HAVE_TYPE] =
      g_signal_new ("have_type", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
                     G_STRUCT_OFFSET (GstTypeFindClass, have_type), NULL, NULL,
                     g_cclosure_marshal_VOID__POINTER, G_TYPE_NONE, 1,
                     G_TYPE_POINTER);

  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_type_find_set_property);
  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_type_find_get_property);

  gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_type_find_change_state);
}

static void
gst_type_find_init (GstTypeFind *typefind)
{
  typefind->sinkpad = gst_pad_new_from_template (
		GST_PAD_TEMPLATE_GET (type_find_sink_factory), "sink");
  gst_element_add_pad (GST_ELEMENT (typefind), typefind->sinkpad);

  gst_element_set_loop_function (GST_ELEMENT (typefind),
				 gst_type_find_loopfunc);

  typefind->caps = NULL;
}

static void
gst_type_find_set_property (GObject *object, guint prop_id, 
		            const GValue *value, GParamSpec *pspec)
{
  GstTypeFind *typefind;

  g_return_if_fail (GST_IS_TYPE_FIND (object));

  typefind = GST_TYPE_FIND (object);

  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_type_find_get_property (GObject *object, guint prop_id, 
		            GValue *value, GParamSpec *pspec)
{
  GstTypeFind *typefind;

  g_return_if_fail (GST_IS_TYPE_FIND (object));

  typefind = GST_TYPE_FIND (object);

  switch (prop_id) {
    case ARG_CAPS:
      g_value_set_pointer (value, typefind->caps);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_type_find_loopfunc (GstElement *element)
{
  GstTypeFind *typefind;
  const GList *type_list;
  GstType *type;

  typefind = GST_TYPE_FIND (element);

  GST_DEBUG ("Started typefinding loop in '%s'",
	     GST_OBJECT_NAME (typefind));

  type_list = gst_type_get_list ();

  while (type_list) {
    GSList *factories;
    type = (GstType *) type_list->data;

    factories = type->factories;

    while (factories) {
      GstTypeFactory *factory = GST_TYPE_FACTORY (factories->data);
      GstTypeFindFunc typefindfunc = (GstTypeFindFunc) factory->typefindfunc;
      GstCaps *caps;

      GST_CAT_DEBUG (GST_CAT_TYPES, "try type (%p) :%d \"%s\" %p", 
		 factory, type->id, type->mime, typefindfunc);
      if (typefindfunc && (caps = typefindfunc (typefind->bs, factory))) {
        GST_CAT_DEBUG (GST_CAT_TYPES, "found type: %d \"%s\" \"%s\"", 
		   caps->id, type->mime, gst_caps_get_name (caps));
	gst_caps_replace (&typefind->caps, caps);

	if (gst_pad_try_set_caps (typefind->sinkpad, caps) <= 0) {
          g_warning ("typefind: found type but peer didn't accept it");
	}

	gst_object_ref (GST_OBJECT (typefind));
	g_signal_emit (G_OBJECT (typefind), gst_type_find_signals[HAVE_TYPE],
		       0, typefind->caps);
	gst_object_unref (GST_OBJECT (typefind));
        return;
      }
      factories = g_slist_next (factories);
    }
    type_list = g_list_next (type_list);
  }

  /* if we get here, nothing worked... :'(. */
  gst_element_error (GST_ELEMENT (typefind), 
		     "media type could not be detected");
}

static GstElementStateReturn
gst_type_find_change_state (GstElement *element)
{
  GstTypeFind *typefind;
  GstElementStateReturn ret;

  typefind = GST_TYPE_FIND (element);

  switch (GST_STATE_TRANSITION (element)) {
    case GST_STATE_READY_TO_PAUSED:
      typefind->bs = gst_bytestream_new (typefind->sinkpad);
      break;
    case GST_STATE_PAUSED_TO_READY:
      gst_bytestream_destroy (typefind->bs);
      gst_caps_replace (&typefind->caps, NULL);
      break;
    default:
      break;
  }
  
  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element);
  
  return ret;
}