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gstreamer/gst/gstelement.h
Thomas Vander Stichele 9b3e3a2613 various doc fixes 
Original commit message from CVS:
various doc fixes
2005-09-11 12:57:36 +00:00

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000,2004 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__
/* gstelement.h and gstelementfactory.h include eachother */
typedef struct _GstElement GstElement;
typedef struct _GstElementClass GstElementClass;
/* gstmessage.h needs State */
typedef enum {
GST_STATE_VOID_PENDING = 0, /* used for GstElement->pending_state when
there is no pending state */
GST_STATE_NULL = 1,
GST_STATE_READY = 2,
GST_STATE_PAUSED = 3,
GST_STATE_PLAYING = 4
} GstState;
#include <gst/gstconfig.h>
#include <gst/gstobject.h>
#include <gst/gstpad.h>
#include <gst/gstbus.h>
#include <gst/gstclock.h>
#include <gst/gstelementfactory.h>
#include <gst/gstplugin.h>
#include <gst/gstpluginfeature.h>
#include <gst/gstindex.h>
#include <gst/gstiterator.h>
#include <gst/gstmessage.h>
#include <gst/gsttaglist.h>
G_BEGIN_DECLS
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))
/**
* GstStateChangeReturn:
* @GST_STATE_CHANGE_FAILURE : the state change failed
* @GST_STATE_CHANGE_SUCCESS : the state change succeeded
* @GST_STATE_CHANGE_ASYNC : the state change will happen asynchronously
* @GST_STATE_CHANGE_NO_PREROLL: the state change cannot be prerolled
*/
typedef enum {
GST_STATE_CHANGE_FAILURE = 0,
GST_STATE_CHANGE_SUCCESS = 1,
GST_STATE_CHANGE_ASYNC = 2,
GST_STATE_CHANGE_NO_PREROLL = 3
} GstStateChangeReturn;
/* 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_FINAL(obj) (GST_ELEMENT(obj)->final_state)
#define GST_STATE_ERROR(obj) (GST_ELEMENT(obj)->state_error)
#define GST_STATE_NO_PREROLL(obj) (GST_ELEMENT(obj)->no_preroll)
#ifndef GST_DEBUG_STATE_CHANGE
#define GST_STATE_CHANGE(obj) ((1<<(GST_STATE(obj)+8)) | 1<<GST_STATE_PENDING(obj))
#else
inline GstStateChange
_gst_element_get_state_change (GstElement *e)
{
if (e->state < GST_STATE_NULL || e->state > GST_STATE_PLAYING)
g_assert_not_reached ();
if (e->pending_state < GST_STATE_NULL || e->pending_state > GST_STATE_PLAYING)
g_assert_not_reached ();
if (e->state - e->pending_state != 1 && e->pending_state - e->state != 1)
g_assert_not_reached ();
return (1<<(GST_STATE(obj)+8)) | 1<<GST_STATE_PENDING(obj);
}
#define GST_STATE_CHANGE(obj) _gst_element_get_state_change(obj)
#endif
/* FIXME: How to deal with lost_state ? */
/**
* GstStateChange:
* @GST_STATE_CHANGE_NULL_TO_READY : state change from NULL to READY
* @GST_STATE_CHANGE_READY_TO_PAUSED : state change from READY to PAUSED
* @GST_STATE_CHANGE_PAUSED_TO_PLAYING: state change from PAUSED to PLAYING
* @GST_STATE_CHANGE_PLAYING_TO_PAUSED: state change from PLAYING to PAUSED
* @GST_STATE_CHANGE_PAUSED_TO_READY : state change from PAUSED to READY
* @GST_STATE_CHANGE_READY_TO_NULL : state change from READY to NULL
*/
typedef enum /*< flags=0 >*/
{
GST_STATE_CHANGE_NULL_TO_READY = 1<<(GST_STATE_NULL+8) | 1<<GST_STATE_READY,
GST_STATE_CHANGE_READY_TO_PAUSED = 1<<(GST_STATE_READY+8) | 1<<GST_STATE_PAUSED,
GST_STATE_CHANGE_PAUSED_TO_PLAYING = 1<<(GST_STATE_PAUSED+8) | 1<<GST_STATE_PLAYING,
GST_STATE_CHANGE_PLAYING_TO_PAUSED = 1<<(GST_STATE_PLAYING+8) | 1<<GST_STATE_PAUSED,
GST_STATE_CHANGE_PAUSED_TO_READY = 1<<(GST_STATE_PAUSED+8) | 1<<GST_STATE_READY,
GST_STATE_CHANGE_READY_TO_NULL = 1<<(GST_STATE_READY+8) | 1<<GST_STATE_NULL
} GstStateChange;
typedef enum
{
/* ignore state changes from parent */
GST_ELEMENT_LOCKED_STATE,
/* the element is a sink */
GST_ELEMENT_IS_SINK,
/* Child is being removed from the parent bin. gst_bin_remove on a
* child already being removed immediately returns FALSE */
GST_ELEMENT_UNPARENTING,
/* use some padding for future expansion */
GST_ELEMENT_FLAG_LAST = GST_OBJECT_FLAG_LAST + 16
} GstElementFlags;
#define GST_ELEMENT_IS_LOCKED_STATE(obj) (GST_FLAG_IS_SET(obj,GST_ELEMENT_LOCKED_STATE))
#define GST_ELEMENT_NAME(obj) (GST_OBJECT_NAME(obj))
#define GST_ELEMENT_PARENT(obj) (GST_ELEMENT_CAST(GST_OBJECT_PARENT(obj)))
#define GST_ELEMENT_BUS(obj) (GST_ELEMENT_CAST(obj)->bus)
#define GST_ELEMENT_CLOCK(obj) (GST_ELEMENT_CAST(obj)->clock)
#define GST_ELEMENT_PADS(obj) (GST_ELEMENT_CAST(obj)->pads)
/**
* GST_ELEMENT_ERROR:
* @el: the element that throws the error
* @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #GstError)
* @code: error code defined for that domain (see #GstError)
* @text: the message to display (format string and args enclosed in
parentheses)
* @debug: debugging information for the message (format string and args
enclosed in parentheses)
*
* Utility function that elements can use in case they encountered a fatal
* data processing error. The pipeline will throw an error signal and the
* application will be requested to stop further media processing.
*/
#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_WARNING_OBJECT (el, "error: %s", __txt); \
if (__dbg) \
GST_WARNING_OBJECT (el, "error: %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, "warning: %s", __txt); \
if (__dbg) \
GST_WARNING_OBJECT (el, "warning: %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));
struct _GstElement
{
GstObject object;
/*< public >*/ /* with STATE_LOCK */
/* element state */
GMutex *state_lock;
GCond *state_cond;
guint8 current_state;
guint8 pending_state;
guint8 final_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. */
gboolean no_preroll; /* flag is set when the element cannot preroll */
/*< public >*/ /* with LOCK */
GstBus *bus;
/* 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;
/*< private >*/
/* signal callbacks */
void (*state_changed) (GstElement *element, GstState old, GstState state);
void (*pad_added) (GstElement *element, GstPad *pad);
void (*pad_removed) (GstElement *element, GstPad *pad);
void (*no_more_pads) (GstElement *element);
/*< public >*/
/* virtual methods for subclasses */
/* request/release pads */
GstPad* (*request_new_pad) (GstElement *element, GstPadTemplate *templ, const gchar* name);
void (*release_pad) (GstElement *element, GstPad *pad);
/* state changes */
GstStateChangeReturn (*get_state) (GstElement * element, GstState * state,
GstState * pending, GTimeVal * timeout);
GstStateChangeReturn (*change_state) (GstElement *element, GstStateChange transition);
/* bus */
void (*set_bus) (GstElement * element, GstBus * bus);
/* 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 functions */
gboolean (*send_event) (GstElement *element, GstEvent *event);
const GstQueryType* (*get_query_types) (GstElement *element);
gboolean (*query) (GstElement *element, GstQuery *query);
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
/* element class pad templates */
void gst_element_class_add_pad_template (GstElementClass *klass, GstPadTemplate *templ);
GstPadTemplate* gst_element_class_get_pad_template (GstElementClass *element_class, const gchar *name);
GList* gst_element_class_get_pad_template_list (GstElementClass *element_class);
void gst_element_class_set_details (GstElementClass *klass,
const GstElementDetails *details);
/* element instance */
GType gst_element_get_type (void);
/* basic name and parentage stuff from GstObject */
#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);
void gst_element_set_base_time (GstElement *element, GstClockTime time);
GstClockTime gst_element_get_base_time (GstElement *element);
/* indexes */
gboolean gst_element_is_indexable (GstElement *element);
void gst_element_set_index (GstElement *element, GstIndex *index);
GstIndex* gst_element_get_index (GstElement *element);
/* bus */
void gst_element_set_bus (GstElement * element, GstBus * bus);
GstBus * gst_element_get_bus (GstElement * element);
/* pad management */
gboolean gst_element_add_pad (GstElement *element, GstPad *pad);
gboolean gst_element_remove_pad (GstElement *element, GstPad *pad);
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);
GstIterator * gst_element_iterate_src_pads (GstElement * element);
GstIterator * gst_element_iterate_sink_pads (GstElement * element);
/* event/query/format stuff */
gboolean gst_element_send_event (GstElement *element, GstEvent *event);
gboolean gst_element_seek (GstElement *element, gdouble rate,
GstFormat format, GstSeekFlags flags,
GstSeekType cur_type, gint64 cur,
GstSeekType stop_type, gint64 stop);
G_CONST_RETURN GstQueryType*
gst_element_get_query_types (GstElement *element);
gboolean gst_element_query (GstElement *element, GstQuery *query);
/* 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);
GstStateChangeReturn gst_element_get_state (GstElement * element,
GstState * state,
GstState * pending,
GTimeVal * timeout);
GstStateChangeReturn gst_element_set_state (GstElement *element, GstState state);
void gst_element_abort_state (GstElement * element);
void gst_element_commit_state (GstElement * element);
void gst_element_lost_state (GstElement * element);
/* factory management */
GstElementFactory* gst_element_get_factory (GstElement *element);
G_END_DECLS
#endif /* __GST_ELEMENT_H__ */
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