1/* GStreamer
2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000,2004 Wim Taymans <wim@fluendo.com>
4 *
5 * gstelement.h: Header for GstElement
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
16 *
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
21 */
22
23
24#ifndef __GST_ELEMENT_H__
25#define __GST_ELEMENT_H__
26
27/* gstelement.h and gstelementfactory.h include eachother */
28typedef struct _GstElement GstElement;
29typedef struct _GstElementClass GstElementClass;
30
31/* gstmessage.h needs State */
32/**
33 * GstState:
34 * @GST_STATE_VOID_PENDING: no pending state.
35 * @GST_STATE_NULL : the NULL state or initial state of an element.
36 * @GST_STATE_READY : the element is ready to go to PAUSED.
37 * @GST_STATE_PAUSED : the element is PAUSED, it is ready to accept and
38 * process data. Sink elements however only accept one
39 * buffer and then block.
40 * @GST_STATE_PLAYING : the element is PLAYING, the #GstClock is running and
41 * the data is flowing.
42 *
43 * The possible states an element can be in. States can be changed using
44 * gst_element_set_state() and checked using gst_element_get_state().
45 */
46typedef enum {
47 GST_STATE_VOID_PENDING = 0,
48 GST_STATE_NULL = 1,
49 GST_STATE_READY = 2,
50 GST_STATE_PAUSED = 3,
51 GST_STATE_PLAYING = 4
52} GstState;
53
54
55#include <gst/gstconfig.h>
56#include <gst/gstobject.h>
57#include <gst/gstpad.h>
58#include <gst/gstbus.h>
59#include <gst/gstclock.h>
60#include <gst/gstelementfactory.h>
61#include <gst/gstplugin.h>
62#include <gst/gstpluginfeature.h>
63#include <gst/gstindex.h>
64#include <gst/gstindexfactory.h>
65#include <gst/gstiterator.h>
66#include <gst/gstmessage.h>
67#include <gst/gsttaglist.h>
68
69G_BEGIN_DECLS
70
71#define GST_TYPE_ELEMENT (gst_element_get_type ())
72#define GST_IS_ELEMENT(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_ELEMENT))
73#define GST_IS_ELEMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_ELEMENT))
74#define GST_ELEMENT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_ELEMENT, GstElementClass))
75#define GST_ELEMENT(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_ELEMENT, GstElement))
76#define GST_ELEMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_ELEMENT, GstElementClass))
77#define GST_ELEMENT_CAST(obj) ((GstElement*)(obj))
78
79/**
80 * GstStateChangeReturn:
81 * @GST_STATE_CHANGE_FAILURE : the state change failed
82 * @GST_STATE_CHANGE_SUCCESS : the state change succeeded
83 * @GST_STATE_CHANGE_ASYNC : the state change will happen asynchronously
84 * @GST_STATE_CHANGE_NO_PREROLL: the state change succeeded but the element
85 * cannot produce data in %GST_STATE_PAUSED.
86 * This typically happens with live sources.
87 *
88 * The possible return values from a state change function such as
89 * gst_element_set_state(). Only @GST_STATE_CHANGE_FAILURE is a real failure.
90 */
91typedef enum {
92 GST_STATE_CHANGE_FAILURE = 0,
93 GST_STATE_CHANGE_SUCCESS = 1,
94 GST_STATE_CHANGE_ASYNC = 2,
95 GST_STATE_CHANGE_NO_PREROLL = 3
96} GstStateChangeReturn;
97
98/* NOTE: this probably should be done with an #ifdef to decide
99 * whether to safe-cast or to just do the non-checking cast.
100 */
101
102/**
103 * GST_STATE:
104 * @elem: a #GstElement to return state for.
105 *
106 * This macro returns the current #GstState of the element.
107 */
108#define GST_STATE(elem) (GST_ELEMENT_CAST(elem)->current_state)
109
110/**
111 * GST_STATE_NEXT:
112 * @elem: a #GstElement to return the next state for.
113 *
114 * This macro returns the next #GstState of the element.
115 */
116#define GST_STATE_NEXT(elem) (GST_ELEMENT_CAST(elem)->next_state)
117
118/**
119 * GST_STATE_PENDING:
120 * @elem: a #GstElement to return the pending state for.
121 *
122 * This macro returns the currently pending #GstState of the element.
123 */
124#define GST_STATE_PENDING(elem) (GST_ELEMENT_CAST(elem)->pending_state)
125
126/**
127 * GST_STATE_TARGET:
128 * @elem: a #GstElement to return the target state for.
129 *
130 * This macro returns the target #GstState of the element.
131 *
132 * Since: 0.10.13
133 */
134#define GST_STATE_TARGET(elem) (GST_ELEMENT_CAST(elem)->abidata.ABI.target_state)
135
136/**
137 * GST_STATE_RETURN:
138 * @elem: a #GstElement to return the last state result for.
139 *
140 * This macro returns the last #GstStateChangeReturn value.
141 */
142#define GST_STATE_RETURN(elem) (GST_ELEMENT_CAST(elem)->last_return)
143
144#define __GST_SIGN(val) ((val) < 0 ? -1 : ((val) > 0 ? 1 : 0))
145/**
146 * GST_STATE_GET_NEXT:
147 * @cur: A starting #GstState
148 * @pending: A target #GstState
149 *
150 * Given a current state @cur and a target state @pending, calculate the next (intermediate)
151 * #GstState.
152 */
153#define GST_STATE_GET_NEXT(cur,pending) ((GstState)((cur) + __GST_SIGN ((gint)(pending) - (gint)(cur))))
154/**
155 * GST_STATE_TRANSITION:
156 * @cur: A current state
157 * @next: A next state
158 *
159 * Given a current state @cur and a next state @next, calculate the associated
160 * #GstStateChange transition.
161 */
162#define GST_STATE_TRANSITION(cur,next) ((GstStateChange)(((cur)<<3)|(next)))
163/**
164 * GST_STATE_TRANSITION_CURRENT:
165 * @trans: A #GstStateChange
166 *
167 * Given a state transition @trans, extract the current #GstState.
168 */
169#define GST_STATE_TRANSITION_CURRENT(trans) ((GstState)((trans)>>3))
170/**
171 * GST_STATE_TRANSITION_NEXT:
172 * @trans: A #GstStateChange
173 *
174 * Given a state transition @trans, extract the next #GstState.
175 */
176#define GST_STATE_TRANSITION_NEXT(trans) ((GstState)((trans)&0x7))
177
178/**
179 * GstStateChange:
180 * @GST_STATE_CHANGE_NULL_TO_READY : state change from NULL to READY.
181 * <itemizedlist>
182 * <listitem><para>
183 * The element must check if the resources it needs are available. Device
184 * sinks and -sources typically try to probe the device to constrain their
185 * caps.
186 * </para></listitem>
187 * <listitem><para>
188 * The element opens the device (in case feature need to be probed).
189 * </para></listitem>
190 * </itemizedlist>
191 * @GST_STATE_CHANGE_READY_TO_PAUSED : state change from READY to PAUSED.
192 * <itemizedlist>
193 * <listitem><para>
194 * The element pads are activated in order to receive data in PAUSED.
195 * Streaming threads are started.
196 * </para></listitem>
197 * <listitem><para>
198 * Some elements might need to return %GST_STATE_CHANGE_ASYNC and complete
199 * the state change when they have enough information. It is a requirement
200 * for sinks to return %GST_STATE_CHANGE_ASYNC and complete the state change
201 * when they receive the first buffer or %GST_EVENT_EOS (preroll).
202 * Sinks also block the dataflow when in PAUSED.
203 * </para></listitem>
204 * <listitem><para>
205 * A pipeline resets the running_time to 0.
206 * </para></listitem>
207 * <listitem><para>
208 * Live sources return %GST_STATE_CHANGE_NO_PREROLL and don't generate data.
209 * </para></listitem>
210 * </itemizedlist>
211 * @GST_STATE_CHANGE_PAUSED_TO_PLAYING: state change from PAUSED to PLAYING.
212 * <itemizedlist>
213 * <listitem><para>
214 * Most elements ignore this state change.
215 * </para></listitem>
216 * <listitem><para>
217 * The pipeline selects a #GstClock and distributes this to all the children
218 * before setting them to PLAYING. This means that it is only alowed to
219 * synchronize on the #GstClock in the PLAYING state.
220 * </para></listitem>
221 * <listitem><para>
222 * The pipeline uses the #GstClock and the running_time to calculate the
223 * base_time. The base_time is distributed to all children when performing
224 * the state change.
225 * </para></listitem>
226 * <listitem><para>
227 * Sink elements stop blocking on the preroll buffer or event and start
228 * rendering the data.
229 * </para></listitem>
230 * <listitem><para>
231 * Sinks can post %GST_MESSAGE_EOS in the PLAYING state. It is not allowed
232 * to post %GST_MESSAGE_EOS when not in the PLAYING state.
233 * </para></listitem>
234 * <listitem><para>
235 * While streaming in PAUSED or PLAYING elements can create and remove
236 * sometimes pads.
237 * </para></listitem>
238 * <listitem><para>
239 * Live sources start generating data and return %GST_STATE_CHANGE_SUCCESS.
240 * </para></listitem>
241 * </itemizedlist>
242 * @GST_STATE_CHANGE_PLAYING_TO_PAUSED: state change from PLAYING to PAUSED.
243 * <itemizedlist>
244 * <listitem><para>
245 * Most elements ignore this state change.
246 * </para></listitem>
247 * <listitem><para>
248 * The pipeline calculates the running_time based on the last selected
249 * #GstClock and the base_time. It stores this information to continue
250 * playback when going back to the PLAYING state.
251 * </para></listitem>
252 * <listitem><para>
253 * Sinks unblock any #GstClock wait calls.
254 * </para></listitem>
255 * <listitem><para>
256 * When a sink does not have a pending buffer to play, it returns
257 * %GST_STATE_CHANGE_ASYNC from this state change and completes the state
258 * change when it receives a new buffer or an %GST_EVENT_EOS.
259 * </para></listitem>
260 * <listitem><para>
261 * Any queued %GST_MESSAGE_EOS items are removed since they will be reposted
262 * when going back to the PLAYING state. The EOS messages are queued in
263 * #GstBin containers.
264 * </para></listitem>
265 * <listitem><para>
266 * Live sources stop generating data and return %GST_STATE_CHANGE_NO_PREROLL.
267 * </para></listitem>
268 * </itemizedlist>
269 * @GST_STATE_CHANGE_PAUSED_TO_READY : state change from PAUSED to READY.
270 * <itemizedlist>
271 * <listitem><para>
272 * Sinks unblock any waits in the preroll.
273 * </para></listitem>
274 * <listitem><para>
275 * Elements unblock any waits on devices
276 * </para></listitem>
277 * <listitem><para>
278 * Chain or get_range functions return %GST_FLOW_WRONG_STATE.
279 * </para></listitem>
280 * <listitem><para>
281 * The element pads are deactivated so that streaming becomes impossible and
282 * all streaming threads are stopped.
283 * </para></listitem>
284 * <listitem><para>
285 * The sink forgets all negotiated formats
286 * </para></listitem>
287 * <listitem><para>
288 * Elements remove all sometimes pads
289 * </para></listitem>
290 * </itemizedlist>
291 * @GST_STATE_CHANGE_READY_TO_NULL : state change from READY to NULL.
292 * <itemizedlist>
293 * <listitem><para>
294 * Elements close devices
295 * </para></listitem>
296 * <listitem><para>
297 * Elements reset any internal state.
298 * </para></listitem>
299 * </itemizedlist>
300 *
301 * These are the different state changes an element goes through.
302 * %GST_STATE_NULL &rArr; %GST_STATE_PLAYING is called an upwards state change
303 * and %GST_STATE_PLAYING &rArr; %GST_STATE_NULL a downwards state change.
304 */
305typedef enum /*< flags=0 >*/
306{
307 GST_STATE_CHANGE_NULL_TO_READY = (GST_STATE_NULL<<3) | GST_STATE_READY,
308 GST_STATE_CHANGE_READY_TO_PAUSED = (GST_STATE_READY<<3) | GST_STATE_PAUSED,
309 GST_STATE_CHANGE_PAUSED_TO_PLAYING = (GST_STATE_PAUSED<<3) | GST_STATE_PLAYING,
310 GST_STATE_CHANGE_PLAYING_TO_PAUSED = (GST_STATE_PLAYING<<3) | GST_STATE_PAUSED,
311 GST_STATE_CHANGE_PAUSED_TO_READY = (GST_STATE_PAUSED<<3) | GST_STATE_READY,
312 GST_STATE_CHANGE_READY_TO_NULL = (GST_STATE_READY<<3) | GST_STATE_NULL
313} GstStateChange;
314
315/**
316 * GstElementFlags:
317 * @GST_ELEMENT_LOCKED_STATE: ignore state changes from parent
318 * @GST_ELEMENT_IS_SINK: the element is a sink
319 * @GST_ELEMENT_UNPARENTING: Child is being removed from the parent bin.
320 * gst_bin_remove() on a child already being removed immediately returns FALSE
321 * @GST_ELEMENT_IS_SOURCE: the element is a source. Since 0.10.31
322 * @GST_ELEMENT_FLAG_LAST: offset to define more flags
323 *
324 * The standard flags that an element may have.
325 */
326typedef enum
327{
328 GST_ELEMENT_LOCKED_STATE = (GST_OBJECT_FLAG_LAST << 0),
329 GST_ELEMENT_IS_SINK = (GST_OBJECT_FLAG_LAST << 1),
330 GST_ELEMENT_UNPARENTING = (GST_OBJECT_FLAG_LAST << 2),
331 GST_ELEMENT_IS_SOURCE = (GST_OBJECT_FLAG_LAST << 3),
332 /* padding */
333 GST_ELEMENT_FLAG_LAST = (GST_OBJECT_FLAG_LAST << 16)
334} GstElementFlags;
335
336/**
337 * GST_ELEMENT_IS_LOCKED_STATE:
338 * @elem: A #GstElement to query
339 *
340 * Check if the element is in the locked state and therefore will ignore state
341 * changes from its parent object.
342 */
343#define GST_ELEMENT_IS_LOCKED_STATE(elem) (GST_OBJECT_FLAG_IS_SET(elem,GST_ELEMENT_LOCKED_STATE))
344
345/**
346 * GST_ELEMENT_NAME:
347 * @elem: A #GstElement to query
348 *
349 * Gets the name of this element. Use only in core as this is not
350 * ABI-compatible. Others use gst_element_get_name()
351 */
352#define GST_ELEMENT_NAME(elem) (GST_OBJECT_NAME(elem))
353
354/**
355 * GST_ELEMENT_PARENT:
356 * @elem: A #GstElement to query
357 *
358 * Get the parent object of this element.
359 */
360#define GST_ELEMENT_PARENT(elem) (GST_ELEMENT_CAST(GST_OBJECT_PARENT(elem)))
361
362/**
363 * GST_ELEMENT_BUS:
364 * @elem: A #GstElement to query
365 *
366 * Get the message bus of this element.
367 */
368#define GST_ELEMENT_BUS(elem) (GST_ELEMENT_CAST(elem)->bus)
369
370/**
371 * GST_ELEMENT_CLOCK:
372 * @elem: A #GstElement to query
373 *
374 * Get the clock of this element
375 */
376#define GST_ELEMENT_CLOCK(elem) (GST_ELEMENT_CAST(elem)->clock)
377
378/**
379 * GST_ELEMENT_PADS:
380 * @elem: A #GstElement to query
381 *
382 * Get the pads of this elements.
383 */
384#define GST_ELEMENT_PADS(elem) (GST_ELEMENT_CAST(elem)->pads)
385
386/**
387 * GST_ELEMENT_START_TIME:
388 * @elem: a #GstElement to return the start time for.
389 *
390 * This macro returns the start_time of the @elem. The start_time is the
391 * running_time of the pipeline when the element went to PAUSED.
392 *
393 * Since: 0.10.24
394 */
395#define GST_ELEMENT_START_TIME(elem) (GST_ELEMENT_CAST(elem)->abidata.ABI.start_time)
396
397/**
398 * GST_ELEMENT_ERROR:
399 * @el: the element that generates the error
400 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
401 * @code: error code defined for that domain (see #gstreamer-GstGError)
402 * @text: the message to display (format string and args enclosed in
403 parentheses)
404 * @debug: debugging information for the message (format string and args
405 enclosed in parentheses)
406 *
407 * Utility function that elements can use in case they encountered a fatal
408 * data processing error. The pipeline will post an error message and the
409 * application will be requested to stop further media processing.
410 */
411#define GST_ELEMENT_ERROR(el, domain, code, text, debug) \
412G_STMT_START { \
413 gchar *__txt = _gst_element_error_printf text; \
414 gchar *__dbg = _gst_element_error_printf debug; \
415 if (__txt) \
416 GST_WARNING_OBJECT (el, "error: %s", __txt); \
417 if (__dbg) \
418 GST_WARNING_OBJECT (el, "error: %s", __dbg); \
419 gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_ERROR, \
420 GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code, \
421 __txt, __dbg, __FILE__, GST_FUNCTION, __LINE__); \
422} G_STMT_END
423
424/**
425 * GST_ELEMENT_WARNING:
426 * @el: the element that generates the warning
427 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
428 * @code: error code defined for that domain (see #gstreamer-GstGError)
429 * @text: the message to display (format string and args enclosed in
430 parentheses)
431 * @debug: debugging information for the message (format string and args
432 enclosed in parentheses)
433 *
434 * Utility function that elements can use in case they encountered a non-fatal
435 * data processing problem. The pipeline will post a warning message and the
436 * application will be informed.
437 */
438#define GST_ELEMENT_WARNING(el, domain, code, text, debug) \
439G_STMT_START { \
440 gchar *__txt = _gst_element_error_printf text; \
441 gchar *__dbg = _gst_element_error_printf debug; \
442 if (__txt) \
443 GST_WARNING_OBJECT (el, "warning: %s", __txt); \
444 if (__dbg) \
445 GST_WARNING_OBJECT (el, "warning: %s", __dbg); \
446 gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_WARNING, \
447 GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code, \
448 __txt, __dbg, __FILE__, GST_FUNCTION, __LINE__); \
449} G_STMT_END
450
451/**
452 * GST_ELEMENT_INFO:
453 * @el: the element that generates the information
454 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)
455 * @code: error code defined for that domain (see #gstreamer-GstGError)
456 * @text: the message to display (format string and args enclosed in
457 parentheses)
458 * @debug: debugging information for the message (format string and args
459 enclosed in parentheses)
460 *
461 * Utility function that elements can use in case they want to inform
462 * the application of something noteworthy that is not an error.
463 * The pipeline will post a info message and the
464 * application will be informed.
465 *
466 * Since: 0.10.12
467 */
468#define GST_ELEMENT_INFO(el, domain, code, text, debug) \
469G_STMT_START { \
470 gchar *__txt = _gst_element_error_printf text; \
471 gchar *__dbg = _gst_element_error_printf debug; \
472 if (__txt) \
473 GST_INFO_OBJECT (el, "info: %s", __txt); \
474 if (__dbg) \
475 GST_INFO_OBJECT (el, "info: %s", __dbg); \
476 gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_INFO, \
477 GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code, \
478 __txt, __dbg, __FILE__, GST_FUNCTION, __LINE__); \
479} G_STMT_END
480
481/* the state change mutexes and conds */
482/**
483 * GST_STATE_GET_LOCK:
484 * @elem: a #GstElement
485 *
486 * Get a reference to the state lock of @elem.
487 * This lock is used by the core. It is taken while getting or setting
488 * the state, during state changes, and while finalizing.
489 */
490#define GST_STATE_GET_LOCK(elem) (GST_ELEMENT_CAST(elem)->state_lock)
491/**
492 * GST_STATE_GET_COND:
493 * @elem: a #GstElement
494 *
495 * Get the conditional used to signal the completion of a state change.
496 */
497#define GST_STATE_GET_COND(elem) (GST_ELEMENT_CAST(elem)->state_cond)
498
499#define GST_STATE_LOCK(elem) g_static_rec_mutex_lock(GST_STATE_GET_LOCK(elem))
500#define GST_STATE_TRYLOCK(elem) g_static_rec_mutex_trylock(GST_STATE_GET_LOCK(elem))
501#define GST_STATE_UNLOCK(elem) g_static_rec_mutex_unlock(GST_STATE_GET_LOCK(elem))
502#define GST_STATE_UNLOCK_FULL(elem) g_static_rec_mutex_unlock_full(GST_STATE_GET_LOCK(elem))
503#define GST_STATE_LOCK_FULL(elem,t) g_static_rec_mutex_lock_full(GST_STATE_GET_LOCK(elem), t)
504#define GST_STATE_WAIT(elem) g_cond_wait (GST_STATE_GET_COND (elem), \
505 GST_OBJECT_GET_LOCK (elem))
506#define GST_STATE_TIMED_WAIT(elem, timeval) g_cond_timed_wait (GST_STATE_GET_COND (elem), \
507 GST_OBJECT_GET_LOCK (elem), timeval)
508#define GST_STATE_SIGNAL(elem) g_cond_signal (GST_STATE_GET_COND (elem));
509#define GST_STATE_BROADCAST(elem) g_cond_broadcast (GST_STATE_GET_COND (elem));
510
511/**
512 * GstElement:
513 * @state_lock: Used to serialize execution of gst_element_set_state()
514 * @state_cond: Used to signal completion of a state change
515 * @state_cookie: Used to detect concurrent execution of
516 * gst_element_set_state() and gst_element_get_state()
517 * @current_state: the current state of an element
518 * @next_state: the next state of an element, can be #GST_STATE_VOID_PENDING if
519 * the element is in the correct state.
520 * @pending_state: the final state the element should go to, can be
521 * #GST_STATE_VOID_PENDING if the element is in the correct state
522 * @last_return: the last return value of an element state change
523 * @bus: the bus of the element. This bus is provided to the element by the
524 * parent element or the application. A #GstPipeline has a bus of its own.
525 * @clock: the clock of the element. This clock is usually provided to the
526 * element by the toplevel #GstPipeline.
527 * @base_time: the time of the clock right before the element is set to
528 * PLAYING. Subtracting @base_time from the current clock time in the PLAYING
529 * state will yield the running_time against the clock.
530 * @numpads: number of pads of the element, includes both source and sink pads.
531 * @pads: list of pads
532 * @numsrcpads: number of source pads of the element.
533 * @srcpads: list of source pads
534 * @numsinkpads: number of sink pads of the element.
535 * @sinkpads: list of sink pads
536 * @pads_cookie: updated whenever the a pad is added or removed
537 *
538 * GStreamer element abstract base class.
539 */
540struct _GstElement
541{
542 GstObject object;
543
544 /*< public >*/ /* with LOCK */
545 GStaticRecMutex *state_lock;
546
547 /* element state */
548 GCond *state_cond;
549 guint32 state_cookie;
550 GstState current_state;
551 GstState next_state;
552 GstState pending_state;
553 GstStateChangeReturn last_return;
554
555 GstBus *bus;
556
557 /* allocated clock */
558 GstClock *clock;
559 GstClockTimeDiff base_time; /* NULL/READY: 0 - PAUSED: current time - PLAYING: difference to clock */
560
561 /* element pads, these lists can only be iterated while holding
562 * the LOCK or checking the cookie after each LOCK. */
563 guint16 numpads;
564 GList *pads;
565 guint16 numsrcpads;
566 GList *srcpads;
567 guint16 numsinkpads;
568 GList *sinkpads;
569 guint32 pads_cookie;
570
571 /*< private >*/
572 union {
573 struct {
574 /* state set by application */
575 GstState target_state;
576 /* running time of the last PAUSED state */
577 GstClockTime start_time;
578 } ABI;
579 /* adding + 0 to mark ABI change to be undone later */
580 gpointer _gst_reserved[GST_PADDING + 0];
581 } abidata;
582};
583
584/**
585 * GstElementClass:
586 * @parent_class: the parent class structure
587 * @details: #GstElementDetails for elements of this class
588 * @elementfactory: the #GstElementFactory that creates these elements
589 * @padtemplates: a #GList of #GstPadTemplate
590 * @numpadtemplates: the number of padtemplates
591 * @pad_templ_cookie: changed whenever the padtemplates change
592 * @request_new_pad: called when a new pad is requested
593 * @release_pad: called when a request pad is to be released
594 * @get_state: get the state of the element
595 * @set_state: set a new state on the element
596 * @change_state: called by @set_state to perform an incremental state change
597 * @set_bus: set a #GstBus on the element
598 * @provide_clock: gets the #GstClock provided by the element
599 * @set_clock: set the #GstClock on the element
600 * @get_index: set a #GstIndex on the element
601 * @set_index: get the #GstIndex of an element
602 * @send_event: send a #GstEvent to the element
603 * @get_query_types: get the supported #GstQueryType of this element
604 * @query: perform a #GstQuery on the element
605 * @request_new_pad_full: called when a new pad is requested. Since: 0.10.32.
606 * @state_changed: called immediately after a new state was set. Since: 0.10.36.
607 * @post_message: called when a message is posted on the element. Chain up to
608 * the parent class' handler to have it posted on the bus. Since: 0.10.37.
609 *
610 * GStreamer element class. Override the vmethods to implement the element
611 * functionality.
612 */
613struct _GstElementClass
614{
615 GstObjectClass parent_class;
616
617 /*< public >*/
618 /* the element details */
619 /* FIXME-0.11: deprecate this in favour of meta_data */
620 GstElementDetails details;
621
622 /* factory that the element was created from */
623 GstElementFactory *elementfactory;
624
625 /* templates for our pads */
626 GList *padtemplates;
627 gint numpadtemplates;
628 guint32 pad_templ_cookie;
629
630 /*< private >*/
631 /* signal callbacks */
632 void (*pad_added) (GstElement *element, GstPad *pad);
633 void (*pad_removed) (GstElement *element, GstPad *pad);
634 void (*no_more_pads) (GstElement *element);
635
636 /*< public >*/
637 /* virtual methods for subclasses */
638
639 /* request/release pads */
640 GstPad* (*request_new_pad) (GstElement *element, GstPadTemplate *templ, const gchar* name);
641 void (*release_pad) (GstElement *element, GstPad *pad);
642
643 /* state changes */
644 GstStateChangeReturn (*get_state) (GstElement * element, GstState * state,
645 GstState * pending, GstClockTime timeout);
646 GstStateChangeReturn (*set_state) (GstElement *element, GstState state);
647 GstStateChangeReturn (*change_state) (GstElement *element, GstStateChange transition);
648
649 /* bus */
650 void (*set_bus) (GstElement * element, GstBus * bus);
651
652 /* set/get clocks */
653 GstClock* (*provide_clock) (GstElement *element);
654 gboolean (*set_clock) (GstElement *element, GstClock *clock);
655
656 /* index */
657 GstIndex* (*get_index) (GstElement *element);
658 void (*set_index) (GstElement *element, GstIndex *index);
659
660 /* query functions */
661 gboolean (*send_event) (GstElement *element, GstEvent *event);
662
663 const GstQueryType* (*get_query_types) (GstElement *element);
664 gboolean (*query) (GstElement *element, GstQuery *query);
665
666 /*< private >*/
667 /* FIXME-0.11: move up and replace details */
668 gpointer meta_data;
669
670 /*< public >*/
671 /* Virtual method for subclasses (additions) */
672 /* FIXME-0.11 Make this the default behaviour */
673 GstPad* (*request_new_pad_full) (GstElement *element, GstPadTemplate *templ,
674 const gchar* name, const GstCaps *caps);
675
676 void (*state_changed) (GstElement *element, GstState oldstate,
677 GstState newstate, GstState pending);
678
679 gboolean (*post_message) (GstElement *element, GstMessage *message);
680};
681
682/* element class pad templates */
683void gst_element_class_add_pad_template (GstElementClass *klass, GstPadTemplate *templ);
684void gst_element_class_add_static_pad_template (GstElementClass *klass, GstStaticPadTemplate *templ);
685GstPadTemplate* gst_element_class_get_pad_template (GstElementClass *element_class, const gchar *name);
686GList* gst_element_class_get_pad_template_list (GstElementClass *element_class);
687
688/* element class meta data */
689void gst_element_class_set_documentation_uri (GstElementClass * klass, const gchar *uri);
690void gst_element_class_set_icon_name (GstElementClass * klass, const gchar *name);
691#ifndef GST_DISABLE_DEPRECATED
692void gst_element_class_set_details (GstElementClass *klass, const GstElementDetails *details);
693#endif
694void gst_element_class_set_details_simple (GstElementClass *klass,
695 const gchar *longname,
696 const gchar *classification,
697 const gchar *description,
698 const gchar *author);
699
700/* element instance */
701GType gst_element_get_type (void);
702
703/* basic name and parentage stuff from GstObject */
704
705/**
706 * gst_element_get_name:
707 * @elem: a #GstElement to get the name of @elem.
708 *
709 * Returns a copy of the name of @elem.
710 * Caller should g_free() the return value after usage.
711 * For a nameless element, this returns NULL, which you can safely g_free()
712 * as well.
713 *
714 * Returns: (transfer full): the name of @elem. g_free() after usage. MT safe.
715 *
716 */
717#define gst_element_get_name(elem) gst_object_get_name(GST_OBJECT_CAST(elem))
718
719/**
720 * gst_element_set_name:
721 * @elem: a #GstElement to set the name of.
722 * @name: the new name
723 *
724 * Sets the name of the element, getting rid of the old name if there was one.
725 */
726#define gst_element_set_name(elem,name) gst_object_set_name(GST_OBJECT_CAST(elem),name)
727
728/**
729 * gst_element_get_parent:
730 * @elem: a #GstElement to get the parent of.
731 *
732 * Get the parent of an element.
733 *
734 * Returns: (transfer full): the parent of an element.
735 */
736#define gst_element_get_parent(elem) gst_object_get_parent(GST_OBJECT_CAST(elem))
737
738/**
739 * gst_element_set_parent:
740 * @elem: a #GstElement to set the parent of.
741 * @parent: the new parent #GstObject of the element.
742 *
743 * Sets the parent of an element.
744 */
745#define gst_element_set_parent(elem,parent) gst_object_set_parent(GST_OBJECT_CAST(elem),parent)
746
747/* clocking */
748gboolean gst_element_requires_clock (GstElement *element);
749gboolean gst_element_provides_clock (GstElement *element);
750GstClock* gst_element_provide_clock (GstElement *element);
751GstClock* gst_element_get_clock (GstElement *element);
752gboolean gst_element_set_clock (GstElement *element, GstClock *clock);
753void gst_element_set_base_time (GstElement *element, GstClockTime time);
754GstClockTime gst_element_get_base_time (GstElement *element);
755void gst_element_set_start_time (GstElement *element, GstClockTime time);
756GstClockTime gst_element_get_start_time (GstElement *element);
757
758/* indexes */
759gboolean gst_element_is_indexable (GstElement *element);
760void gst_element_set_index (GstElement *element, GstIndex *index);
761GstIndex* gst_element_get_index (GstElement *element);
762
763/* bus */
764void gst_element_set_bus (GstElement * element, GstBus * bus);
765GstBus * gst_element_get_bus (GstElement * element);
766
767/* pad management */
768gboolean gst_element_add_pad (GstElement *element, GstPad *pad);
769gboolean gst_element_remove_pad (GstElement *element, GstPad *pad);
770void gst_element_no_more_pads (GstElement *element);
771
772#ifndef GST_DISABLE_DEPRECATED
773GstPad* gst_element_get_pad (GstElement *element, const gchar *name);
774#endif /* GST_DISABLE_DEPRECATED */
775GstPad* gst_element_get_static_pad (GstElement *element, const gchar *name);
776GstPad* gst_element_get_request_pad (GstElement *element, const gchar *name);
777GstPad* gst_element_request_pad (GstElement *element,
778 GstPadTemplate *templ,
779 const gchar * name, const GstCaps *caps);
780void gst_element_release_request_pad (GstElement *element, GstPad *pad);
781
782GstIterator * gst_element_iterate_pads (GstElement * element);
783GstIterator * gst_element_iterate_src_pads (GstElement * element);
784GstIterator * gst_element_iterate_sink_pads (GstElement * element);
785
786/* event/query/format stuff */
787gboolean gst_element_send_event (GstElement *element, GstEvent *event);
788gboolean gst_element_seek (GstElement *element, gdouble rate,
789 GstFormat format, GstSeekFlags flags,
790 GstSeekType cur_type, gint64 cur,
791 GstSeekType stop_type, gint64 stop);
792const GstQueryType* gst_element_get_query_types (GstElement *element);
793gboolean gst_element_query (GstElement *element, GstQuery *query);
794
795/* messages */
796gboolean gst_element_post_message (GstElement * element, GstMessage * message);
797
798/* error handling */
799/* gcc versions < 3.3 warn about NULL being passed as format to printf */
800#if (defined(GST_USING_PRINTF_EXTENSION) || !defined(__GNUC__) || (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 3))
801gchar * _gst_element_error_printf (const gchar *format, ...);
802#else
803gchar * _gst_element_error_printf (const gchar *format, ...) G_GNUC_PRINTF (1, 2);
804#endif
805void gst_element_message_full (GstElement * element, GstMessageType type,
806 GQuark domain, gint code, gchar * text,
807 gchar * debug, const gchar * file,
808 const gchar * function, gint line);
809
810/* state management */
811gboolean gst_element_is_locked_state (GstElement *element);
812gboolean gst_element_set_locked_state (GstElement *element, gboolean locked_state);
813gboolean gst_element_sync_state_with_parent (GstElement *element);
814
815GstStateChangeReturn gst_element_get_state (GstElement * element,
816 GstState * state,
817 GstState * pending,
818 GstClockTime timeout);
819GstStateChangeReturn gst_element_set_state (GstElement *element, GstState state);
820
821void gst_element_abort_state (GstElement * element);
822GstStateChangeReturn gst_element_change_state (GstElement * element,
823 GstStateChange transition);
824GstStateChangeReturn gst_element_continue_state (GstElement * element,
825 GstStateChangeReturn ret);
826void gst_element_lost_state (GstElement * element);
827void gst_element_lost_state_full (GstElement * element, gboolean new_base_time);
828
829/* factory management */
830GstElementFactory* gst_element_get_factory (GstElement *element);
831
832G_END_DECLS
833
834#endif /* __GST_ELEMENT_H__ */
835