2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
4 * 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
6 * gstthread.c: Threaded container object
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
24 #include "gst_private.h"
26 #include "gstthread.h"
27 #include "gstscheduler.h"
31 #define GST_CAT_DEFAULT GST_CAT_THREAD
32 #define STACK_SIZE 0x200000
34 static GstElementDetails gst_thread_details = GST_ELEMENT_DETAILS (
37 "Container that creates/manages a thread",
38 "Erik Walthinsen <omega@cse.ogi.edu>, "
39 "Benjamin Otte <in7y118@informatik.uni-hamburg.de"
42 /* Thread signals and args */
61 static void gst_thread_base_init (gpointer g_class);
62 static void gst_thread_class_init (gpointer g_class, gpointer class_data);
63 static void gst_thread_init (GTypeInstance *instance, gpointer g_class);
65 static void gst_thread_dispose (GObject *object);
67 static void gst_thread_set_property (GObject *object, guint prop_id,
68 const GValue *value, GParamSpec *pspec);
69 static void gst_thread_get_property (GObject *object, guint prop_id,
70 GValue *value, GParamSpec *pspec);
71 static GstElementStateReturn gst_thread_change_state (GstElement *element);
72 static void gst_thread_child_state_change (GstBin *bin, GstElementState oldstate,
73 GstElementState newstate, GstElement *element);
75 static void gst_thread_catch (GstThread *thread);
76 static void gst_thread_release (GstThread *thread);
78 #ifndef GST_DISABLE_LOADSAVE
79 static xmlNodePtr gst_thread_save_thyself (GstObject *object,
81 static void gst_thread_restore_thyself (GstObject *object,
85 static void * gst_thread_main_loop (void *arg);
87 #define GST_TYPE_THREAD_PRIORITY (gst_thread_priority_get_type())
89 gst_thread_priority_get_type(void)
91 static GType thread_priority_type = 0;
92 static GEnumValue thread_priority[] =
94 { G_THREAD_PRIORITY_LOW, "LOW", "Low Priority Scheduling" },
95 { G_THREAD_PRIORITY_NORMAL, "NORMAL", "Normal Scheduling" },
96 { G_THREAD_PRIORITY_HIGH, "HIGH", "High Priority Scheduling" },
97 { G_THREAD_PRIORITY_URGENT, "URGENT", "Urgent Scheduling" },
100 if (!thread_priority_type) {
101 thread_priority_type = g_enum_register_static("GstThreadPriority", thread_priority);
103 return thread_priority_type;
106 static GstBinClass *parent_class = NULL;
107 static guint gst_thread_signals[LAST_SIGNAL] = { 0 };
108 GPrivate *gst_thread_current;
111 gst_thread_get_type(void) {
112 static GType thread_type = 0;
115 static const GTypeInfo thread_info = {
116 sizeof (GstThreadClass),
117 gst_thread_base_init,
119 gst_thread_class_init,
127 thread_type = g_type_register_static (GST_TYPE_BIN, "GstThread",
134 gst_thread_base_init (gpointer g_class)
136 GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
138 gst_element_class_set_details (gstelement_class, &gst_thread_details);
140 static void do_nothing (gpointer hi) {}
142 gst_thread_class_init (gpointer g_class, gpointer class_data)
144 GObjectClass *gobject_class = G_OBJECT_CLASS (g_class);
145 GstObjectClass *gstobject_class = GST_OBJECT_CLASS (g_class);
146 GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
147 GstBinClass *gstbin_class = GST_BIN_CLASS (g_class);
148 GstThreadClass *klass = GST_THREAD_CLASS (g_class);
150 /* setup gst_thread_current */
151 gst_thread_current = g_private_new (do_nothing);
153 parent_class = g_type_class_peek_parent (g_class);
155 g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_PRIORITY,
156 g_param_spec_enum ("priority", "Scheduling Policy", "The scheduling priority of the thread",
157 GST_TYPE_THREAD_PRIORITY, G_THREAD_PRIORITY_NORMAL, G_PARAM_READWRITE));
159 gst_thread_signals[SHUTDOWN] =
160 g_signal_new ("shutdown", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
161 G_STRUCT_OFFSET (GstThreadClass, shutdown), NULL, NULL,
162 gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
164 gobject_class->dispose = gst_thread_dispose;
166 #ifndef GST_DISABLE_LOADSAVE
167 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_thread_save_thyself);
168 gstobject_class->restore_thyself = GST_DEBUG_FUNCPTR (gst_thread_restore_thyself);
171 gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_thread_change_state);
173 gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_thread_set_property);
174 gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_thread_get_property);
176 gstbin_class->child_state_change = GST_DEBUG_FUNCPTR (gst_thread_child_state_change);
180 gst_thread_init (GTypeInstance *instance, gpointer g_class)
182 GstScheduler *scheduler;
183 GstThread *thread = GST_THREAD (instance);
185 GST_DEBUG ("initializing thread");
187 /* threads are managing bins and iterate themselves */
188 /* CR1: the GstBin code checks these flags */
189 GST_FLAG_SET (thread, GST_BIN_FLAG_MANAGER);
190 GST_FLAG_SET (thread, GST_BIN_SELF_SCHEDULABLE);
192 scheduler = gst_scheduler_factory_make (NULL, GST_ELEMENT (thread));
193 g_assert (scheduler);
195 thread->lock = g_mutex_new ();
196 thread->cond = g_cond_new ();
198 thread->thread_id = (GThread *) NULL; /* set in NULL -> READY */
199 thread->priority = G_THREAD_PRIORITY_NORMAL;
203 gst_thread_dispose (GObject *object)
205 GstThread *thread = GST_THREAD (object);
207 GST_CAT_DEBUG (GST_CAT_REFCOUNTING, "GstThread: dispose");
209 G_OBJECT_CLASS (parent_class)->dispose (object);
211 g_assert (GST_STATE (thread) == GST_STATE_NULL);
213 g_mutex_free (thread->lock);
214 g_cond_free (thread->cond);
216 gst_object_replace ((GstObject **)&GST_ELEMENT_SCHED (thread), NULL);
220 * gst_thread_set_priority:
221 * @thread: the thread to change
222 * @priority: the new priority for the thread
224 * change the thread's priority
227 gst_thread_set_priority (GstThread *thread, GThreadPriority priority)
229 g_return_if_fail (GST_IS_THREAD (thread));
231 thread->priority = priority;
235 gst_thread_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
239 thread = GST_THREAD (object);
243 thread->priority = g_value_get_enum (value);
246 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
252 gst_thread_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
256 thread = GST_THREAD (object);
260 g_value_set_enum (value, thread->priority);
263 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
271 * @name: the name of the thread
273 * Create a new thread with the given name.
275 * Returns: The new thread
278 gst_thread_new (const gchar *name)
280 return gst_element_factory_make ("thread", name);
284 * gst_thread_get_current:
286 * Create a new thread with the given name.
288 * Returns: The current GstThread or NULL if you are not running inside a
292 gst_thread_get_current (void)
294 return (GstThread *) g_private_get (gst_thread_current);
298 gst_thread_release_children_locks (GstThread *thread)
300 GstRealPad *peer = NULL;
301 GstElement *peerelement;
302 GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
305 GstElement *element = GST_ELEMENT (elements->data);
309 GST_DEBUG_OBJECT (thread, "waking element \"%s\"", GST_ELEMENT_NAME (element));
310 elements = g_list_next (elements);
312 if (!gst_element_release_locks (element))
313 g_warning ("element %s could not release locks", GST_ELEMENT_NAME (element));
315 pads = GST_ELEMENT_PADS (element);
318 if (GST_PAD_PEER (pads->data)) {
319 peer = GST_REAL_PAD (GST_PAD_PEER (pads->data));
320 pads = g_list_next (pads);
322 pads = g_list_next (pads);
329 peerelement = GST_PAD_PARENT (peer);
331 continue; /* FIXME: deal with case where there's no peer */
333 if (GST_ELEMENT_SCHED (peerelement) != GST_ELEMENT_SCHED (thread)) {
334 GST_LOG_OBJECT (thread, "element \"%s\" has pad cross sched boundary", GST_ELEMENT_NAME (element));
335 GST_LOG_OBJECT (thread, "waking element \"%s\"", GST_ELEMENT_NAME (peerelement));
336 if (!gst_element_release_locks (peerelement))
337 g_warning ("element %s could not release locks", GST_ELEMENT_NAME (peerelement));
342 /* stops the main thread, if there is one and grabs the thread's mutex */
344 gst_thread_catch (GstThread *thread)
347 if (thread == gst_thread_get_current()) {
348 /* we're trying to catch ourself */
349 if (!GST_FLAG_IS_SET (thread, GST_THREAD_MUTEX_LOCKED)) {
350 g_mutex_lock (thread->lock);
351 GST_FLAG_SET (thread, GST_THREAD_MUTEX_LOCKED);
353 GST_DEBUG_OBJECT (thread, "catching itself");
354 GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
356 /* another thread is trying to catch us */
357 g_mutex_lock (thread->lock);
358 wait = !GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING);
361 GST_LOG_OBJECT (thread, "catching thread...");
362 GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
363 g_cond_signal (thread->cond);
364 gst_thread_release_children_locks (thread);
365 g_get_current_time (&tv);
366 g_time_val_add (&tv, 1000); /* wait a millisecond to catch the thread */
367 wait = g_cond_timed_wait (thread->cond, thread->lock, &tv);
369 GST_LOG_OBJECT (thread, "caught thread");
371 g_assert (!GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING));
375 gst_thread_release (GstThread *thread)
377 if (thread != gst_thread_get_current()) {
378 g_cond_signal (thread->cond);
379 g_mutex_unlock (thread->lock);
383 static GstElementStateReturn
384 gst_thread_change_state (GstElement *element)
387 GstElementStateReturn ret;
390 g_return_val_if_fail (GST_IS_THREAD (element), GST_STATE_FAILURE);
391 transition = GST_STATE_TRANSITION (element);
393 thread = GST_THREAD (element);
395 GST_DEBUG_OBJECT (element, "changing state from %s to %s",
396 gst_element_state_get_name (GST_STATE (element)),
397 gst_element_state_get_name (GST_STATE_PENDING (element)));
399 gst_thread_catch (thread);
401 /* FIXME: (or GStreamers ideas about "threading"): the element variables are
402 commonly accessed by multiple threads at the same time (see bug #111146
404 if (transition != GST_STATE_TRANSITION (element)) {
405 g_warning ("inconsistent state information, fix threading please");
408 switch (transition) {
409 case GST_STATE_NULL_TO_READY:
410 /* create the thread */
411 GST_FLAG_UNSET (thread, GST_THREAD_STATE_REAPING);
412 thread->thread_id = g_thread_create_full(gst_thread_main_loop,
413 thread, STACK_SIZE, FALSE, TRUE, thread->priority,
415 if (!thread->thread_id){
416 GST_ERROR_OBJECT (element, "g_thread_create_full failed");
419 GST_LOG_OBJECT (element, "GThread created");
421 /* wait for it to 'spin up' */
422 g_cond_wait (thread->cond, thread->lock);
424 case GST_STATE_READY_TO_PAUSED:
426 case GST_STATE_PAUSED_TO_PLAYING:
428 /* FIXME: recurse into sub-bins */
429 GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
431 gst_element_enable_threadsafe_properties ((GstElement*)elements->data);
432 elements = g_list_next (elements);
434 /* reset self to spinning */
435 if (thread == gst_thread_get_current())
436 GST_FLAG_SET (thread, GST_THREAD_STATE_SPINNING);
439 case GST_STATE_PLAYING_TO_PAUSED:
441 GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
443 gst_element_disable_threadsafe_properties ((GstElement*)elements->data);
444 elements = g_list_next (elements);
448 case GST_STATE_PAUSED_TO_READY:
450 case GST_STATE_READY_TO_NULL:
451 /* we can't join the threads here, because this could have been triggered
453 GST_LOG_OBJECT (thread, "destroying GThread %p", thread->thread_id);
454 GST_FLAG_SET (thread, GST_THREAD_STATE_REAPING);
455 thread->thread_id = NULL;
456 if (thread == gst_thread_get_current()) {
457 /* or should we continue? */
458 g_warning ("Thread %s is destroying itself. Function call will not return!", GST_ELEMENT_NAME (thread));
459 gst_scheduler_reset (GST_ELEMENT_SCHED (thread));
461 /* unlock and signal - we are out */
462 gst_thread_release (thread);
464 GST_INFO_OBJECT (thread, "GThread %p is exiting", g_thread_self());
466 g_signal_emit (G_OBJECT (thread), gst_thread_signals[SHUTDOWN], 0);
468 g_thread_exit (NULL);
470 /* now wait for the thread to destroy itself */
471 g_cond_signal (thread->cond);
472 g_cond_wait (thread->cond, thread->lock);
473 /* it should be dead now */
476 GST_ERROR_OBJECT (element, "UNHANDLED STATE CHANGE! %x",
477 GST_STATE_TRANSITION (element));
478 g_assert_not_reached ();
482 if (GST_ELEMENT_CLASS (parent_class)->change_state) {
483 ret = GST_ELEMENT_CLASS (parent_class)->change_state (GST_ELEMENT (thread));
485 ret = GST_STATE_SUCCESS;
488 gst_thread_release (thread);
492 GST_CAT_DEBUG (GST_CAT_STATES, "changing state from %s to %s failed for %s",
493 gst_element_state_get_name (GST_STATE (element)),
494 gst_element_state_get_name (GST_STATE_PENDING (element)),
495 GST_ELEMENT_NAME (element));
496 gst_thread_release (thread);
497 return GST_STATE_FAILURE;
500 /* state changes work this way: We grab the lock and stop the thread from
501 spinning (via gst_thread_catch) - then we change the state. After that the
502 thread may spin on. */
504 gst_thread_child_state_change (GstBin *bin, GstElementState oldstate,
505 GstElementState newstate, GstElement *element)
507 GST_LOG_OBJECT (bin, "(from thread %s) child %s changed state from %s to %s",
508 gst_thread_get_current() ? GST_ELEMENT_NAME (gst_thread_get_current()) : "(none)",
509 GST_ELEMENT_NAME (element), gst_element_state_get_name (oldstate),
510 gst_element_state_get_name (newstate));
511 if (parent_class->child_state_change)
512 parent_class->child_state_change (bin, oldstate, newstate, element);
513 /* We'll wake up the main thread now. Note that we can't lock the thread here,
514 because we might be called from inside gst_thread_change_state when holding
515 the lock. But this doesn't cause any problems. */
516 if (newstate == GST_STATE_PLAYING)
517 g_cond_signal (GST_THREAD (bin)->cond);
520 * gst_thread_main_loop:
521 * @arg: the thread to start
523 * The main loop of the thread. The thread will iterate
524 * while the state is GST_THREAD_STATE_SPINNING.
527 gst_thread_main_loop (void *arg)
529 GstThread *thread = NULL;
532 thread = GST_THREAD (arg);
533 g_mutex_lock (thread->lock);
534 GST_LOG_OBJECT (thread, "Started main loop");
536 /* initialize gst_thread_current */
537 g_private_set (gst_thread_current, thread);
539 /* set up the element's scheduler */
540 gst_scheduler_setup (GST_ELEMENT_SCHED (thread));
541 GST_FLAG_UNSET (thread, GST_THREAD_STATE_REAPING);
543 g_cond_signal (thread->cond);
544 while (!(GST_FLAG_IS_SET (thread, GST_THREAD_STATE_REAPING))) {
545 if (GST_STATE (thread) == GST_STATE_PLAYING) {
546 GST_FLAG_SET (thread, GST_THREAD_STATE_SPINNING);
548 GST_LOG_OBJECT (thread, "starting to iterate");
549 while (status && GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING)) {
550 g_mutex_unlock (thread->lock);
551 status = gst_bin_iterate (GST_BIN (thread));
552 if (GST_FLAG_IS_SET (thread, GST_THREAD_MUTEX_LOCKED)) {
553 GST_FLAG_UNSET (thread, GST_THREAD_MUTEX_LOCKED);
555 g_mutex_lock (thread->lock);
558 GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
560 if (GST_FLAG_IS_SET (thread, GST_THREAD_STATE_REAPING))
562 GST_LOG_OBJECT (thread, "we're caught");
563 g_cond_signal (thread->cond);
564 g_cond_wait (thread->cond, thread->lock);
567 /* we need to destroy the scheduler here because it has mapped it's
568 * stack into the threads stack space */
569 gst_scheduler_reset (GST_ELEMENT_SCHED (thread));
571 /* must do that before releasing the lock - we might get disposed before being done */
572 g_signal_emit (G_OBJECT (thread), gst_thread_signals[SHUTDOWN], 0);
574 /* unlock and signal - we are out */
576 GST_LOG_OBJECT (thread, "Thread %p exits main loop", g_thread_self());
577 g_cond_signal (thread->cond);
578 g_mutex_unlock (thread->lock);
579 /* don't assume the GstThread object exists anymore now */
584 #ifndef GST_DISABLE_LOADSAVE
586 gst_thread_save_thyself (GstObject *object,
589 if (GST_OBJECT_CLASS (parent_class)->save_thyself)
590 GST_OBJECT_CLASS (parent_class)->save_thyself (object, self);
595 gst_thread_restore_thyself (GstObject *object,
598 GST_LOG_OBJECT (object, "restoring");
600 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
601 GST_OBJECT_CLASS (parent_class)->restore_thyself (object, self);
603 #endif /* GST_DISABLE_LOADSAVE */