gstreamer/gst/gstelement.h

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *                    2004 Wim Taymans <wim@fluendo.com>
 *
 * gstelement.h: Header for GstElement
 *
 * 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_ELEMENT_H__
#define __GST_ELEMENT_H__

#include <gst/gstconfig.h>
#include <gst/gsttypes.h>
#include <gst/gstobject.h>
#include <gst/gstpad.h>
#include <gst/gstclock.h>
#include <gst/gstplugin.h>
#include <gst/gstpluginfeature.h>
#include <gst/gstindex.h>
#include <gst/gstiterator.h>
#include <gst/gstmessage.h>
#include <gst/gsttag.h>

G_BEGIN_DECLS typedef struct _GstElementDetails GstElementDetails;

/* FIXME: need translatable stuff in here (how handle in registry)? */
struct _GstElementDetails
{
  /*< public > */
  gchar *longname;              /* long, english name */
  gchar *klass;                 /* type of element, as hierarchy */
  gchar *description;           /* insights of one form or another */
  gchar *author;                /* who wrote this thing? */

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

#define GST_ELEMENT_DETAILS(longname,klass,description,author)			\
  { longname, klass, description, author, GST_PADDING_INIT }
#define GST_IS_ELEMENT_DETAILS(details) (					\
  (details) && ((details)->longname != NULL) && ((details)->klass != NULL)	\
  && ((details)->description != NULL) && ((details)->author != NULL))

#define GST_NUM_STATES 4

/* NOTE: this probably should be done with an #ifdef to decide 
 * whether to safe-cast or to just do the non-checking cast.
 */
#define GST_STATE(obj)			(GST_ELEMENT(obj)->current_state)
#define GST_STATE_PENDING(obj)		(GST_ELEMENT(obj)->pending_state)
#define GST_STATE_ERROR(obj)		(GST_ELEMENT(obj)->state_error)

/* Note: using 8 bit shift mostly "just because", it leaves us enough room to grow <g> */
#define GST_STATE_TRANSITION(obj)	((GST_STATE(obj)<<8) | GST_STATE_PENDING(obj))
#define GST_STATE_NULL_TO_READY		((GST_STATE_NULL<<8) | GST_STATE_READY)
#define GST_STATE_READY_TO_PAUSED	((GST_STATE_READY<<8) | GST_STATE_PAUSED)
#define GST_STATE_PAUSED_TO_PLAYING	((GST_STATE_PAUSED<<8) | GST_STATE_PLAYING)
#define GST_STATE_PLAYING_TO_PAUSED	((GST_STATE_PLAYING<<8) | GST_STATE_PAUSED)
#define GST_STATE_PAUSED_TO_READY	((GST_STATE_PAUSED<<8) | GST_STATE_READY)
#define GST_STATE_READY_TO_NULL		((GST_STATE_READY<<8) | GST_STATE_NULL)

GST_EXPORT GType _gst_element_type;

#define GST_TYPE_ELEMENT		(_gst_element_type)
#define GST_IS_ELEMENT(obj)		(G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_ELEMENT))
#define GST_IS_ELEMENT_CLASS(klass)	(G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_ELEMENT))
#define GST_ELEMENT_GET_CLASS(obj)	(G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_ELEMENT, GstElementClass))
#define GST_ELEMENT(obj)		(G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_ELEMENT, GstElement))
#define GST_ELEMENT_CLASS(klass)	(G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_ELEMENT, GstElementClass))
#define GST_ELEMENT_CAST(obj)		((GstElement*)(obj))

/* convenience functions */
#ifdef G_HAVE_ISO_VARARGS
#define GST_ELEMENT_QUERY_TYPE_FUNCTION(functionname, ...) \
	GST_QUERY_TYPE_FUNCTION (GstElement*, functionname, __VA_ARGS__);
#define GST_ELEMENT_FORMATS_FUNCTION(functionname, ...)    \
	GST_FORMATS_FUNCTION (GstElement*, functionname, __VA_ARGS__);
#define GST_ELEMENT_EVENT_MASK_FUNCTION(functionname, ...) \
	GST_EVENT_MASK_FUNCTION (GstElement*, functionname, __VA_ARGS__);
#elif defined(G_HAVE_GNUC_VARARGS)
#define GST_ELEMENT_QUERY_TYPE_FUNCTION(functionname, a...) \
	GST_QUERY_TYPE_FUNCTION (GstElement*, functionname, a);
#define GST_ELEMENT_FORMATS_FUNCTION(functionname, a...)    \
	GST_FORMATS_FUNCTION (GstElement*, functionname, a);
#define GST_ELEMENT_EVENT_MASK_FUNCTION(functionname, a...) \
	GST_EVENT_MASK_FUNCTION (GstElement*, functionname, a);
#endif

typedef enum
{
  /* private flags that can be used by the scheduler */
  GST_ELEMENT_SCHEDULER_PRIVATE1,
  GST_ELEMENT_SCHEDULER_PRIVATE2,

  /* ignore state changes from parent */
  GST_ELEMENT_LOCKED_STATE,

  /* use some padding for future expansion */
  GST_ELEMENT_FLAG_LAST = GST_OBJECT_FLAG_LAST + 16
} GstElementFlags;

#define GST_ELEMENT_NAME(obj)			(GST_OBJECT_NAME(obj))
#define GST_ELEMENT_PARENT(obj)			(GST_ELEMENT_CAST(GST_OBJECT_PARENT(obj)))
#define GST_ELEMENT_MANAGER(obj)		(GST_ELEMENT_CAST(obj)->manager)
#define GST_ELEMENT_BUS(obj)			(GST_ELEMENT_CAST(obj)->bus)
#define GST_ELEMENT_SCHEDULER(obj)		(GST_ELEMENT_CAST(obj)->scheduler)
#define GST_ELEMENT_CLOCK(obj)			(GST_ELEMENT_CAST(obj)->clock)
#define GST_ELEMENT_PADS(obj)			(GST_ELEMENT_CAST(obj)->pads)

/* log a (fatal) error message and post it on the bus */
#define GST_ELEMENT_ERROR(el, domain, code, text, debug)		\
G_STMT_START {								\
  gchar *__txt = _gst_element_error_printf text;			\
  gchar *__dbg = _gst_element_error_printf debug;			\
  if (__txt)								\
    GST_ERROR_OBJECT (el, "%s", __txt);					\
  if (__dbg)								\
    GST_ERROR_OBJECT (el, "%s", __dbg);					\
  gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_ERROR,		\
    GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code,	\
  __txt, __dbg, __FILE__, GST_FUNCTION, __LINE__);			\
} G_STMT_END

/* log a (non-fatal) warning message and post it on the bus */
#define GST_ELEMENT_WARNING(el, domain, code, text, debug)		\
G_STMT_START {								\
  gchar *__txt = _gst_element_error_printf text;			\
  gchar *__dbg = _gst_element_error_printf debug;			\
  if (__txt)								\
    GST_WARNING_OBJECT (el, "%s", __txt);				\
  if (__dbg)								\
    GST_WARNING_OBJECT (el, "%s", __dbg);				\
  gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_WARNING,	\
    GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code,	\
  __txt, __dbg, __FILE__, GST_FUNCTION, __LINE__);			\
} G_STMT_END

/* the state change mutexes and conds */
#define GST_STATE_GET_LOCK(elem)               (GST_ELEMENT_CAST(elem)->state_lock)
#define GST_STATE_LOCK(elem)                   g_mutex_lock(GST_STATE_GET_LOCK(elem))
#define GST_STATE_TRYLOCK(elem)                g_mutex_trylock(GST_STATE_GET_LOCK(elem))
#define GST_STATE_UNLOCK(elem)                 g_mutex_unlock(GST_STATE_GET_LOCK(elem))
#define GST_STATE_GET_COND(elem)               (GST_ELEMENT_CAST(elem)->state_cond)
#define GST_STATE_WAIT(elem)                   g_cond_wait (GST_STATE_GET_COND (elem), GST_STATE_GET_LOCK (elem))
#define GST_STATE_TIMED_WAIT(elem, timeval)    g_cond_timed_wait (GST_STATE_GET_COND (elem), GST_STATE_GET_LOCK (elem),\
						timeval)
#define GST_STATE_SIGNAL(elem)                 g_cond_signal (GST_STATE_GET_COND (elem));
#define GST_STATE_BROADCAST(elem)              g_cond_broadcast (GST_STATE_GET_COND (elem));

typedef struct _GstElementFactory GstElementFactory;
typedef struct _GstElementFactoryClass GstElementFactoryClass;

struct _GstElement
{
  GstObject object;

  /*< public > *//* with STATE_LOCK */
  /* element state */
  GMutex   *state_lock;
  GCond    *state_cond;
  guint8    current_state;
  guint8    pending_state;
  gboolean  state_error; /* flag is set when the element has an error in the last state
			    change. it is cleared when doing another state change. */

  /*< public > *//* with LOCK */
  /* element manager */
  GstPipeline  *manager;
  GstBus       *bus;
  GstScheduler *scheduler;
  /* private pointer for the scheduler */
  gpointer      sched_private;

  /* allocated clock */
  GstClock         *clock;
  GstClockTimeDiff  base_time;   /* NULL/READY: 0 - PAUSED: current time - PLAYING: difference to clock */

  /* element pads, these lists can only be iterated while holding
   * the LOCK or checking the cookie after each LOCK. */
  guint16   numpads;
  GList    *pads;
  guint16   numsrcpads;
  GList    *srcpads;
  guint16   numsinkpads;
  GList    *sinkpads;
  guint32   pads_cookie;

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

struct _GstElementClass
{
  GstObjectClass parent_class;

  /*< public > */
  /* the element details */
  GstElementDetails details;

  /* factory that the element was created from */
  GstElementFactory *elementfactory;

  /* templates for our pads */
  GList *padtemplates;
  gint numpadtemplates;
  guint32 pad_templ_cookie;

  /* signal callbacks */
  void (*state_change) (GstElement * element, GstElementState old,
      GstElementState state);
  void (*new_pad) (GstElement * element, GstPad * pad);
  void (*pad_removed) (GstElement * element, GstPad * pad);
  void (*no_more_pads) (GstElement * element);

  /*< protected > */
  /* vtable */

  /* request/release pads */
  GstPad *(*request_new_pad) (GstElement * element, GstPadTemplate * templ,
      const gchar * name);
  void (*release_pad) (GstElement * element, GstPad * pad);

  /* state changes */
  GstElementStateReturn (*get_state) 	(GstElement * element, GstElementState * state,
      					 GstElementState * pending, GTimeVal * timeout);
  GstElementStateReturn (*change_state) (GstElement * element);

  /* manager */
  void (*set_manager) (GstElement * element, GstPipeline * pipeline);
  void (*set_bus) (GstElement * element, GstBus * bus);
  void (*set_scheduler) (GstElement * element, GstScheduler * scheduler);

  /* set/get clocks */
  GstClock *(*get_clock) (GstElement * element);
  void (*set_clock) (GstElement * element, GstClock * clock);

  /* index */
  GstIndex *(*get_index) (GstElement * element);
  void (*set_index) (GstElement * element, GstIndex * index);

  /* query/convert/events functions */
  const GstEventMask *(*get_event_masks) (GstElement * element);
    gboolean (*send_event) (GstElement * element, GstEvent * event);
  const GstFormat *(*get_formats) (GstElement * element);
    gboolean (*convert) (GstElement * element,
      GstFormat src_format, gint64 src_value,
      GstFormat * dest_format, gint64 * dest_value);
  const GstQueryType *(*get_query_types) (GstElement * element);
    gboolean (*query) (GstElement * element, GstQueryType type,
      GstFormat * format, gint64 * value);

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

/* class stuff */
void gst_element_class_add_pad_template (GstElementClass * klass,
    GstPadTemplate * templ);
void gst_element_class_set_details (GstElementClass * klass,
    const GstElementDetails * details);
GstPadTemplate *gst_element_class_get_pad_template (GstElementClass *
    element_class, const gchar * name);
GList *gst_element_class_get_pad_template_list (GstElementClass *
    element_class);

/* element instance */

GType gst_element_get_type (void);

#define			gst_element_get_name(elem)		gst_object_get_name(GST_OBJECT(elem))
#define			gst_element_set_name(elem,name)		gst_object_set_name(GST_OBJECT(elem),name)
#define			gst_element_get_parent(elem)		gst_object_get_parent(GST_OBJECT(elem))
#define			gst_element_set_parent(elem,parent)	gst_object_set_parent(GST_OBJECT(elem),parent)

/* clocking */
gboolean gst_element_requires_clock (GstElement * element);
gboolean gst_element_provides_clock (GstElement * element);
GstClock *gst_element_get_clock (GstElement * element);
void gst_element_set_clock (GstElement * element, GstClock * clock);

GstClockReturn gst_element_clock_wait (GstElement * element,
    GstClockID id, GstClockTimeDiff * jitter);
GstClockTime gst_element_get_time (GstElement * element);
gboolean gst_element_wait (GstElement * element, GstClockTime timestamp);

/* indexes */
gboolean gst_element_is_indexable (GstElement * element);
void gst_element_set_index (GstElement * element, GstIndex * index);
GstIndex *gst_element_get_index (GstElement * element);

/* manager and tasks */
void gst_element_set_manager (GstElement * element, GstPipeline * pipeline);
GstPipeline *gst_element_get_manager (GstElement * element);
void gst_element_set_bus (GstElement * element, GstBus * bus);
GstBus *gst_element_get_bus (GstElement * element);
void gst_element_set_scheduler (GstElement * element, GstScheduler * scheduler);
GstScheduler *gst_element_get_scheduler (GstElement * element);

/* pad management */
gboolean gst_element_add_pad (GstElement * element, GstPad * pad);
gboolean gst_element_remove_pad (GstElement * element, GstPad * pad);
GstPad *gst_element_add_ghost_pad (GstElement * element, GstPad * pad,
    const gchar * name);
void gst_element_no_more_pads (GstElement * element);

GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
GstPad *gst_element_get_static_pad (GstElement * element, const gchar * name);
GstPad *gst_element_get_request_pad (GstElement * element, const gchar * name);
void gst_element_release_request_pad (GstElement * element, GstPad * pad);

GstIterator *gst_element_iterate_pads (GstElement * element);

/* event/query/format stuff */
G_CONST_RETURN GstEventMask *gst_element_get_event_masks (GstElement * element);
gboolean gst_element_send_event (GstElement * element, GstEvent * event);
gboolean gst_element_seek (GstElement * element, GstSeekType seek_type,
    guint64 offset);
G_CONST_RETURN GstQueryType *gst_element_get_query_types (GstElement * element);
gboolean gst_element_query (GstElement * element, GstQueryType type,
    GstFormat * format, gint64 * value);
G_CONST_RETURN GstFormat *gst_element_get_formats (GstElement * element);
gboolean gst_element_convert (GstElement * element,
    GstFormat src_format, gint64 src_value,
    GstFormat * dest_format, gint64 * dest_value);

/* messages */
gboolean gst_element_post_message (GstElement * element, GstMessage * message);


/* error handling */
gchar *_gst_element_error_printf (const gchar * format, ...);
void gst_element_message_full (GstElement * element, GstMessageType type,
    GQuark domain, gint code, gchar * text, gchar * debug, const gchar * file,
    const gchar * function, gint line);

/* state management */
gboolean 		gst_element_is_locked_state 		(GstElement * element);
gboolean 		gst_element_set_locked_state 		(GstElement * element,
   								 gboolean locked_state);
gboolean 		gst_element_sync_state_with_parent 	(GstElement * element);

GstElementStateReturn 	gst_element_get_state 			(GstElement * element, 
								 GstElementState * state,
    								 GstElementState * pending, 
								 GTimeVal * timeout);
GstElementStateReturn 	gst_element_set_state 			(GstElement * element,
   								 GstElementState state);

void 			gst_element_abort_state 		(GstElement * element);
void 			gst_element_commit_state 		(GstElement * element);

/* factory management */
GstElementFactory *gst_element_get_factory (GstElement * element);

/*
 *
 * factories stuff
 *
 **/

#define GST_TYPE_ELEMENT_FACTORY 		(gst_element_factory_get_type())
#define GST_ELEMENT_FACTORY(obj)  		(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_ELEMENT_FACTORY,\
						 GstElementFactory))
#define GST_ELEMENT_FACTORY_CLASS(klass) 	(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ELEMENT_FACTORY,\
						 GstElementFactoryClass))
#define GST_IS_ELEMENT_FACTORY(obj) 		(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_ELEMENT_FACTORY))
#define GST_IS_ELEMENT_FACTORY_CLASS(klass) 	(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_ELEMENT_FACTORY))

struct _GstElementFactory
{
  GstPluginFeature parent;

  GType type;                   /* unique GType of element or 0 if not loaded */

  GstElementDetails details;

  GList *padtemplates;
  guint numpadtemplates;

  /* URI interface stuff */
  guint uri_type;
  gchar **uri_protocols;

  GList *interfaces;            /* interfaces this element implements */

  gpointer _gst_reserved[GST_PADDING];
};

struct _GstElementFactoryClass
{
  GstPluginFeatureClass parent_class;

  gpointer _gst_reserved[GST_PADDING];
};

GType gst_element_factory_get_type (void);

gboolean gst_element_register (GstPlugin * plugin,
    const gchar * name, guint rank, GType type);

GstElementFactory *gst_element_factory_find (const gchar * name);
GType gst_element_factory_get_element_type (GstElementFactory * factory);
G_CONST_RETURN gchar *gst_element_factory_get_longname (GstElementFactory *
    factory);
G_CONST_RETURN gchar *gst_element_factory_get_klass (GstElementFactory *
    factory);
G_CONST_RETURN gchar *gst_element_factory_get_description (GstElementFactory *
    factory);
G_CONST_RETURN gchar *gst_element_factory_get_author (GstElementFactory *
    factory);
guint gst_element_factory_get_num_pad_templates (GstElementFactory * factory);
G_CONST_RETURN GList *gst_element_factory_get_pad_templates (GstElementFactory *
    factory);
guint gst_element_factory_get_uri_type (GstElementFactory * factory);
gchar **gst_element_factory_get_uri_protocols (GstElementFactory * factory);

GstElement *gst_element_factory_create (GstElementFactory * factory,
    const gchar * name);
GstElement *gst_element_factory_make (const gchar * factoryname,
    const gchar * name);

void                    __gst_element_factory_add_pad_template  (GstElementFactory *elementfactory,
                                                                 GstPadTemplate *templ);
void                    __gst_element_factory_add_interface     (GstElementFactory *elementfactory,
                                                                 const gchar *interfacename);

G_END_DECLS
#endif /* __GST_ELEMENT_H__ */