gstreamer/gst/gstpluginfeature.h

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *
 * gstpluginfeature.h: Header for base GstPluginFeature
 *
 * 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.
 */


#ifndef __GST_PLUGIN_FEATURE_H__
#define __GST_PLUGIN_FEATURE_H__

#include <glib-object.h>
#include <gst/gstobject.h>
#include <gst/gstplugin.h>

G_BEGIN_DECLS

#define GST_TYPE_PLUGIN_FEATURE                 (gst_plugin_feature_get_type())
#define GST_PLUGIN_FEATURE(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_PLUGIN_FEATURE, GstPluginFeature))
#define GST_IS_PLUGIN_FEATURE(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_PLUGIN_FEATURE))
#define GST_PLUGIN_FEATURE_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_PLUGIN_FEATURE, GstPluginFeatureClass))
#define GST_IS_PLUGIN_FEATURE_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_PLUGIN_FEATURE))
#define GST_PLUGIN_FEATURE_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_PLUGIN_FEATURE, GstPluginFeatureClass))
#define GST_PLUGIN_FEATURE_CAST(obj)            ((GstPluginFeature*)(obj))

typedef struct _GstPluginFeature GstPluginFeature;
typedef struct _GstPluginFeatureClass GstPluginFeatureClass;

/**
 * GstRank:
 * @GST_RANK_NONE: will be chosen last or not at all
 * @GST_RANK_MARGINAL: unlikly to be chosen
 * @GST_RANK_SECONDARY: likely to be chosen
 * @GST_RANK_PRIMARY: will be chosen first
 *
 * Element priority ranks. Defines the order in which the autoplugger (or
 * similar rank-picking mechanisms, such as e.g. gst_element_make_from_uri())
 * will choose this element over an alternative one with the same function.
 *
 * These constants serve as a rough guidance for defining the rank of a
 * #GstPluginFeature. Any value is valid, including values bigger than
 * @GST_RANK_PRIMARY.
 */
typedef enum {
  GST_RANK_NONE                 = 0,
  GST_RANK_MARGINAL             = 64,
  GST_RANK_SECONDARY            = 128,
  GST_RANK_PRIMARY              = 256
} GstRank;

/**
 * gst_plugin_feature_get_name:
 * @feature: a #GstPluginFeature to get the name of @feature.
 *
 * Returns a copy of the name of @feature.
 * Caller should g_free() the return value after usage.
 * For a nameless plugin feature, this returns NULL, which you can safely g_free()
 * as well.
 *
 * Returns: (transfer full): the name of @feature. g_free() after usage. MT safe.
 *
 */
#define                 gst_plugin_feature_get_name(feature)      gst_object_get_name(GST_OBJECT_CAST(feature))

/**
 * gst_plugin_feature_set_name:
 * @feature: a #GstPluginFeature to set the name of.
 * @name: the new name
 *
 * Sets the name of the plugin feature, getting rid of the old name if there was one.
 */
#define                 gst_plugin_feature_set_name(feature,name) gst_object_set_name(GST_OBJECT_CAST(feature),name)

/**
 * GstPluginFeature:
 *
 * Opaque #GstPluginFeature structure.
 */
struct _GstPluginFeature {
  GstObject      object;

  /*< private >*/
  gboolean       loaded;
  guint          rank;

  const gchar   *plugin_name;
  GstPlugin     *plugin;      /* weak ref */

  /*< private >*/
  gpointer _gst_reserved[GST_PADDING - 1];
};

struct _GstPluginFeatureClass {
  GstObjectClass        parent_class;

  /*< private >*/
  gpointer _gst_reserved[GST_PADDING];
};

/**
 * GstTypeNameData:
 * @name: a name
 * @type: a GType
 *
 * Structure used for filtering based on @name and @type.
 */
typedef struct {
  const gchar   *name;
  GType          type;
} GstTypeNameData;

/**
 * GstPluginFeatureFilter:
 * @feature: the pluginfeature to check
 * @user_data: the user_data that has been passed on e.g.
 *  gst_registry_feature_filter()
 *
 * A function that can be used with e.g. gst_registry_feature_filter()
 * to get a list of pluginfeature that match certain criteria.
 *
 * Returns: %TRUE for a positive match, %FALSE otherwise
 */
typedef gboolean        (*GstPluginFeatureFilter)       (GstPluginFeature *feature,
                                                         gpointer user_data);

/* normal GObject stuff */
GType           gst_plugin_feature_get_type             (void);

GstPluginFeature *
                gst_plugin_feature_load                 (GstPluginFeature *feature);

gboolean        gst_plugin_feature_type_name_filter     (GstPluginFeature *feature,
                                                         GstTypeNameData *data);

void            gst_plugin_feature_set_rank             (GstPluginFeature *feature, guint rank);
guint           gst_plugin_feature_get_rank             (GstPluginFeature *feature);

void            gst_plugin_feature_list_free            (GList *list);
GList          *gst_plugin_feature_list_copy            (GList *list);
void            gst_plugin_feature_list_debug           (GList *list);

/**
 * GST_PLUGIN_FEATURE_LIST_DEBUG:
 * @list: (transfer none) (element-type Gst.PluginFeature): a #GList of
 *     plugin features
 *
 * Debug the plugin feature names in @list.
 *
 * Since: 0.10.31
 */
#ifndef GST_DISABLE_GST_DEBUG
#define GST_PLUGIN_FEATURE_LIST_DEBUG(list) gst_plugin_feature_list_debug(list)
#else
#define GST_PLUGIN_FEATURE_LIST_DEBUG(list)
#endif

gboolean        gst_plugin_feature_check_version        (GstPluginFeature *feature,
                                                         guint             min_major,
                                                         guint             min_minor,
                                                         guint             min_micro);
gint            gst_plugin_feature_rank_compare_func    (gconstpointer p1,
							 gconstpointer p2);

G_END_DECLS


#endif /* __GST_PLUGIN_FEATURE_H__ */