root/gst/gstsystemclock.c
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DEFINITIONS
This source file includes following definitions.
- gst_system_clock_class_init
- gst_system_clock_init
- gst_system_clock_dispose
- gst_system_clock_set_property
- gst_system_clock_get_property
- gst_system_clock_obtain
- gst_system_clock_remove_wakeup
- gst_system_clock_add_wakeup
- gst_system_clock_wait_wakeup
- gst_system_clock_async_thread
- clock_type_to_posix_id
- gst_system_clock_get_internal_time
- gst_system_clock_get_resolution
- gst_system_clock_id_wait_jitter_unlocked
- gst_system_clock_id_wait_jitter
- gst_system_clock_start_async
- gst_system_clock_id_wait_async
- gst_system_clock_id_unschedule
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2004 Wim Taymans <wim@fluendo.com>
*
* gstsystemclock.c: Default clock, uses the system clock
*
* 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.
*/
/**
* SECTION:gstsystemclock
* @short_description: Default clock that uses the current system time
* @see_also: #GstClock
*
* The GStreamer core provides a GstSystemClock based on the system time.
* Asynchronous callbacks are scheduled from an internal thread.
*
* Clock implementors are encouraged to subclass this systemclock as it
* implements the async notification.
*
* Subclasses can however override all of the important methods for sync and
* async notifications to implement their own callback methods or blocking
* wait operations.
*
* Last reviewed on 2006-03-08 (0.10.4)
*/
#include "gst_private.h"
#include "gstinfo.h"
#include "gstsystemclock.h"
#include "gstenumtypes.h"
#include "gstpoll.h"
#include "gstutils.h"
#include <errno.h>
#ifdef G_OS_WIN32
# define WIN32_LEAN_AND_MEAN /* prevents from including too many things */
# include <windows.h> /* QueryPerformance* stuff */
# undef WIN32_LEAN_AND_MEAN
#endif /* G_OS_WIN32 */
/* Define this to get some extra debug about jitter from each clock_wait */
#undef WAIT_DEBUGGING
struct _GstSystemClockPrivate
{
GstClockType clock_type;
GstPoll *timer;
gint wakeup_count; /* the number of entries with a pending wakeup */
gboolean async_wakeup; /* if the wakeup was because of a async list change */
#ifdef G_OS_WIN32
LARGE_INTEGER start;
LARGE_INTEGER frequency;
#endif /* G_OS_WIN32 */
};
#define GST_SYSTEM_CLOCK_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_SYSTEM_CLOCK, \
GstSystemClockPrivate))
#ifdef HAVE_POSIX_TIMERS
# ifdef HAVE_MONOTONIC_CLOCK
# define DEFAULT_CLOCK_TYPE GST_CLOCK_TYPE_MONOTONIC
# else
# define DEFAULT_CLOCK_TYPE GST_CLOCK_TYPE_REALTIME
# endif
#else
#define DEFAULT_CLOCK_TYPE GST_CLOCK_TYPE_REALTIME
#endif
enum
{
PROP_0,
PROP_CLOCK_TYPE,
/* FILL ME */
};
/* the one instance of the systemclock */
static GstClock *_the_system_clock = NULL;
static void gst_system_clock_dispose (GObject * object);
static void gst_system_clock_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_system_clock_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstClockTime gst_system_clock_get_internal_time (GstClock * clock);
static guint64 gst_system_clock_get_resolution (GstClock * clock);
static GstClockReturn gst_system_clock_id_wait_jitter (GstClock * clock,
GstClockEntry * entry, GstClockTimeDiff * jitter);
static GstClockReturn gst_system_clock_id_wait_jitter_unlocked
(GstClock * clock, GstClockEntry * entry, GstClockTimeDiff * jitter,
gboolean restart);
static GstClockReturn gst_system_clock_id_wait_async (GstClock * clock,
GstClockEntry * entry);
static void gst_system_clock_id_unschedule (GstClock * clock,
GstClockEntry * entry);
static void gst_system_clock_async_thread (GstClock * clock);
static gboolean gst_system_clock_start_async (GstSystemClock * clock);
static void gst_system_clock_add_wakeup (GstSystemClock * sysclock);
static GStaticMutex _gst_sysclock_mutex = G_STATIC_MUTEX_INIT;
static GstClockClass *parent_class = NULL;
/* static guint gst_system_clock_signals[LAST_SIGNAL] = { 0 }; */
G_DEFINE_TYPE (GstSystemClock, gst_system_clock, GST_TYPE_CLOCK);
static void
gst_system_clock_class_init (GstSystemClockClass * klass)
{
GObjectClass *gobject_class;
GstClockClass *gstclock_class;
gobject_class = (GObjectClass *) klass;
gstclock_class = (GstClockClass *) klass;
parent_class = g_type_class_peek_parent (klass);
g_type_class_add_private (klass, sizeof (GstSystemClockPrivate));
gobject_class->dispose = gst_system_clock_dispose;
gobject_class->set_property = gst_system_clock_set_property;
gobject_class->get_property = gst_system_clock_get_property;
g_object_class_install_property (gobject_class, PROP_CLOCK_TYPE,
g_param_spec_enum ("clock-type", "Clock type",
"The type of underlying clock implementation used",
GST_TYPE_CLOCK_TYPE, DEFAULT_CLOCK_TYPE, G_PARAM_READWRITE));
gstclock_class->get_internal_time = gst_system_clock_get_internal_time;
gstclock_class->get_resolution = gst_system_clock_get_resolution;
gstclock_class->wait_jitter = gst_system_clock_id_wait_jitter;
gstclock_class->wait_async = gst_system_clock_id_wait_async;
gstclock_class->unschedule = gst_system_clock_id_unschedule;
}
static void
gst_system_clock_init (GstSystemClock * clock)
{
GST_OBJECT_FLAG_SET (clock,
GST_CLOCK_FLAG_CAN_DO_SINGLE_SYNC |
GST_CLOCK_FLAG_CAN_DO_SINGLE_ASYNC |
GST_CLOCK_FLAG_CAN_DO_PERIODIC_SYNC |
GST_CLOCK_FLAG_CAN_DO_PERIODIC_ASYNC);
clock->priv = GST_SYSTEM_CLOCK_GET_PRIVATE (clock);
clock->priv->clock_type = DEFAULT_CLOCK_TYPE;
clock->priv->timer = gst_poll_new_timer ();
#ifdef G_OS_WIN32
QueryPerformanceFrequency (&clock->priv->frequency);
/* can be 0 if the hardware does not have hardware support */
if (clock->priv->frequency.QuadPart != 0)
/* we take a base time so that time starts from 0 to ease debugging */
QueryPerformanceCounter (&clock->priv->start);
#endif /* G_OS_WIN32 */
#if 0
/* Uncomment this to start the async clock thread straight away */
GST_OBJECT_LOCK (clock);
gst_system_clock_start_async (clock);
GST_OBJECT_UNLOCK (clock);
#endif
}
static void
gst_system_clock_dispose (GObject * object)
{
GstClock *clock = (GstClock *) object;
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GList *entries;
/* else we have to stop the thread */
GST_OBJECT_LOCK (clock);
sysclock->stopping = TRUE;
/* unschedule all entries */
for (entries = clock->entries; entries; entries = g_list_next (entries)) {
GstClockEntry *entry = (GstClockEntry *) entries->data;
GST_CAT_DEBUG (GST_CAT_CLOCK, "unscheduling entry %p", entry);
entry->status = GST_CLOCK_UNSCHEDULED;
}
g_list_free (clock->entries);
clock->entries = NULL;
GST_CLOCK_BROADCAST (clock);
gst_system_clock_add_wakeup (sysclock);
GST_OBJECT_UNLOCK (clock);
if (sysclock->thread)
g_thread_join (sysclock->thread);
sysclock->thread = NULL;
GST_CAT_DEBUG (GST_CAT_CLOCK, "joined thread");
gst_poll_free (sysclock->priv->timer);
G_OBJECT_CLASS (parent_class)->dispose (object);
if (_the_system_clock == clock) {
_the_system_clock = NULL;
GST_CAT_DEBUG (GST_CAT_CLOCK, "disposed system clock");
}
}
static void
gst_system_clock_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK (object);
switch (prop_id) {
case PROP_CLOCK_TYPE:
sysclock->priv->clock_type = g_value_get_enum (value);
GST_CAT_DEBUG (GST_CAT_CLOCK, "clock-type set to %d",
sysclock->priv->clock_type);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_system_clock_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK (object);
switch (prop_id) {
case PROP_CLOCK_TYPE:
g_value_set_enum (value, sysclock->priv->clock_type);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/**
* gst_system_clock_obtain:
*
* Get a handle to the default system clock. The refcount of the
* clock will be increased so you need to unref the clock after
* usage.
*
* Returns: the default clock.
*
* MT safe.
*/
GstClock *
gst_system_clock_obtain (void)
{
GstClock *clock;
g_static_mutex_lock (&_gst_sysclock_mutex);
clock = _the_system_clock;
if (clock == NULL) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "creating new static system clock");
clock = g_object_new (GST_TYPE_SYSTEM_CLOCK,
"name", "GstSystemClock", NULL);
/* we created the global clock; take ownership so
* we can hand out instances later */
gst_object_ref_sink (clock);
_the_system_clock = clock;
g_static_mutex_unlock (&_gst_sysclock_mutex);
} else {
g_static_mutex_unlock (&_gst_sysclock_mutex);
GST_CAT_DEBUG (GST_CAT_CLOCK, "returning static system clock");
}
/* we ref it since we are a clock factory. */
gst_object_ref (clock);
return clock;
}
static void
gst_system_clock_remove_wakeup (GstSystemClock * sysclock)
{
g_return_if_fail (sysclock->priv->wakeup_count > 0);
sysclock->priv->wakeup_count--;
if (sysclock->priv->wakeup_count == 0) {
/* read the control socket byte when we removed the last wakeup count */
GST_CAT_DEBUG (GST_CAT_CLOCK, "reading control");
while (!gst_poll_read_control (sysclock->priv->timer)) {
g_warning ("gstsystemclock: read control failed, trying again\n");
}
GST_CLOCK_BROADCAST (sysclock);
}
GST_CAT_DEBUG (GST_CAT_CLOCK, "wakeup count %d",
sysclock->priv->wakeup_count);
}
static void
gst_system_clock_add_wakeup (GstSystemClock * sysclock)
{
/* only write the control socket for the first wakeup */
if (sysclock->priv->wakeup_count == 0) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "writing control");
while (!gst_poll_write_control (sysclock->priv->timer)) {
g_warning
("gstsystemclock: write control failed in wakeup_async, trying again : %d:%s\n",
errno, g_strerror (errno));
}
}
sysclock->priv->wakeup_count++;
GST_CAT_DEBUG (GST_CAT_CLOCK, "wakeup count %d",
sysclock->priv->wakeup_count);
}
static void
gst_system_clock_wait_wakeup (GstSystemClock * sysclock)
{
while (sysclock->priv->wakeup_count > 0) {
GST_CLOCK_WAIT (sysclock);
}
}
/* this thread reads the sorted clock entries from the queue.
*
* It waits on each of them and fires the callback when the timeout occurs.
*
* When an entry in the queue was canceled before we wait for it, it is
* simply skipped.
*
* When waiting for an entry, it can become canceled, in that case we don't
* call the callback but move to the next item in the queue.
*
* MT safe.
*/
static void
gst_system_clock_async_thread (GstClock * clock)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "enter system clock thread");
GST_OBJECT_LOCK (clock);
/* signal spinup */
GST_CLOCK_BROADCAST (clock);
/* now enter our (almost) infinite loop */
while (!sysclock->stopping) {
GstClockEntry *entry;
GstClockTime requested;
GstClockReturn res;
/* check if something to be done */
while (clock->entries == NULL) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "no clock entries, waiting..");
/* wait for work to do */
GST_CLOCK_WAIT (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "got signal");
/* clock was stopping, exit */
if (sysclock->stopping)
goto exit;
}
/* see if we have a pending wakeup because the order of the list
* changed. */
if (sysclock->priv->async_wakeup) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "clear async wakeup");
gst_system_clock_remove_wakeup (sysclock);
sysclock->priv->async_wakeup = FALSE;
}
/* pick the next entry */
entry = clock->entries->data;
/* if it was unscheduled, just move on to the next entry */
if (entry->status == GST_CLOCK_UNSCHEDULED) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p was unscheduled", entry);
goto next_entry;
}
requested = entry->time;
/* now wait for the entry, we already hold the lock */
res =
gst_system_clock_id_wait_jitter_unlocked (clock, (GstClockID) entry,
NULL, FALSE);
switch (res) {
case GST_CLOCK_UNSCHEDULED:
/* entry was unscheduled, move to the next */
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry %p unscheduled", entry);
goto next_entry;
case GST_CLOCK_OK:
case GST_CLOCK_EARLY:
{
/* entry timed out normally, fire the callback and move to the next
* entry */
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry %p timed out", entry);
if (entry->func) {
/* unlock before firing the callback */
GST_OBJECT_UNLOCK (clock);
entry->func (clock, entry->time, (GstClockID) entry,
entry->user_data);
GST_OBJECT_LOCK (clock);
}
if (entry->type == GST_CLOCK_ENTRY_PERIODIC) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "updating periodic entry %p", entry);
/* adjust time now */
entry->time = requested + entry->interval;
/* and resort the list now */
clock->entries =
g_list_sort (clock->entries, gst_clock_id_compare_func);
/* and restart */
continue;
} else {
GST_CAT_DEBUG (GST_CAT_CLOCK, "moving to next entry");
goto next_entry;
}
}
case GST_CLOCK_BUSY:
/* somebody unlocked the entry but is was not canceled, This means that
* either a new entry was added in front of the queue or some other entry
* was canceled. Whatever it is, pick the head entry of the list and
* continue waiting. */
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry %p needs restart", entry);
/* we set the entry back to the OK state. This is needed so that the
* _unschedule() code can see if an entry is currently being waited
* on (when its state is BUSY). */
entry->status = GST_CLOCK_OK;
continue;
default:
GST_CAT_DEBUG (GST_CAT_CLOCK,
"strange result %d waiting for %p, skipping", res, entry);
g_warning ("%s: strange result %d waiting for %p, skipping",
GST_OBJECT_NAME (clock), res, entry);
goto next_entry;
}
next_entry:
/* we remove the current entry and unref it */
clock->entries = g_list_remove (clock->entries, entry);
gst_clock_id_unref ((GstClockID) entry);
}
exit:
/* signal exit */
GST_CLOCK_BROADCAST (clock);
GST_OBJECT_UNLOCK (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "exit system clock thread");
}
#ifdef HAVE_POSIX_TIMERS
static inline clockid_t
clock_type_to_posix_id (GstClockType clock_type)
{
#ifdef HAVE_MONOTONIC_CLOCK
if (clock_type == GST_CLOCK_TYPE_MONOTONIC)
return CLOCK_MONOTONIC;
else
#endif
return CLOCK_REALTIME;
}
#endif
/* MT safe */
static GstClockTime
gst_system_clock_get_internal_time (GstClock * clock)
{
#ifdef G_OS_WIN32
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
if (sysclock->priv->frequency.QuadPart != 0) {
LARGE_INTEGER now;
/* we prefer the highly accurate performance counters on windows */
QueryPerformanceCounter (&now);
return gst_util_uint64_scale (now.QuadPart - sysclock->priv->start.QuadPart,
GST_SECOND, sysclock->priv->frequency.QuadPart);
} else
#endif /* G_OS_WIN32 */
#if !defined HAVE_POSIX_TIMERS
{
GTimeVal timeval;
g_get_current_time (&timeval);
return GST_TIMEVAL_TO_TIME (timeval);
}
#else
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
if (G_UNLIKELY (clock_gettime (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return GST_TIMESPEC_TO_TIME (ts);
}
#endif
}
static guint64
gst_system_clock_get_resolution (GstClock * clock)
{
#ifdef G_OS_WIN32
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
if (sysclock->priv->frequency.QuadPart != 0) {
return GST_SECOND / sysclock->priv->frequency.QuadPart;
} else
#endif /* G_OS_WIN32 */
#ifdef HAVE_POSIX_TIMERS
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
clockid_t ptype;
struct timespec ts;
ptype = clock_type_to_posix_id (sysclock->priv->clock_type);
if (G_UNLIKELY (clock_getres (ptype, &ts)))
return GST_CLOCK_TIME_NONE;
return GST_TIMESPEC_TO_TIME (ts);
}
#else
{
return 1 * GST_USECOND;
}
#endif
}
/* synchronously wait on the given GstClockEntry.
*
* We do this by blocking on the global clock GCond variable with
* the requested time as a timeout. This allows us to unblock the
* entry by signaling the GCond variable.
*
* Note that signaling the global GCond unlocks all waiting entries. So
* we need to check if an unlocked entry has changed when it unlocks.
*
* Entries that arrive too late are simply not waited on and a
* GST_CLOCK_EARLY result is returned.
*
* should be called with LOCK held.
*
* MT safe.
*/
static GstClockReturn
gst_system_clock_id_wait_jitter_unlocked (GstClock * clock,
GstClockEntry * entry, GstClockTimeDiff * jitter, gboolean restart)
{
GstSystemClock *sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GstClockTime entryt, real, now;
GstClockTimeDiff diff;
/* need to call the overridden method because we want to sync against the time
* of the clock, whatever the subclass uses as a clock. */
real = GST_CLOCK_GET_CLASS (clock)->get_internal_time (clock);
now = gst_clock_adjust_unlocked (clock, real);
/* get the time of the entry */
entryt = GST_CLOCK_ENTRY_TIME (entry);
if (jitter) {
*jitter = GST_CLOCK_DIFF (entryt, now);
}
/* the diff of the entry with the clock is the amount of time we have to
* wait */
diff = entryt - now;
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p"
" time %" GST_TIME_FORMAT
" now %" GST_TIME_FORMAT
" real %" GST_TIME_FORMAT
" diff (time-now) %" G_GINT64_FORMAT,
entry,
GST_TIME_ARGS (entryt), GST_TIME_ARGS (now), GST_TIME_ARGS (real), diff);
if (diff > 0) {
#ifdef WAIT_DEBUGGING
GstClockTime final;
#endif
while (entry->status != GST_CLOCK_UNSCHEDULED) {
gint pollret;
/* mark the entry as busy */
entry->status = GST_CLOCK_BUSY;
GST_OBJECT_UNLOCK (clock);
/* now wait on the entry, it either times out or the fd is written. */
pollret = gst_poll_wait (sysclock->priv->timer, diff);
/* another thread can read the fd before we get the lock */
GST_OBJECT_LOCK (clock);
if (entry->status == GST_CLOCK_UNSCHEDULED) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p unlocked", entry);
gst_system_clock_remove_wakeup (sysclock);
} else {
if (pollret != 0) {
/* some other id got unlocked */
if (!restart) {
/* this can happen if the entry got unlocked because of an async
* entry was added to the head of the async queue. */
GST_CAT_DEBUG (GST_CAT_CLOCK, "wakeup waiting for entry %p", entry);
break;
}
/* mark ourselves as EARLY, we release the lock and we could be
* unscheduled ourselves but we don't want the unscheduling thread
* to write on the control socket (it does that when an entry has a
* BUSY status). */
entry->status = GST_CLOCK_EARLY;
/* wait till all the entries got woken up */
gst_system_clock_wait_wakeup (sysclock);
/* we released the lock in the wait, recheck our status, we don't need
* to remove the wakeup count because we marked the entry as EARLY
* before releasing the object lock. */
if (entry->status == GST_CLOCK_UNSCHEDULED) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p got unscheduled", entry);
break;
}
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p needs to be restarted",
entry);
} else {
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry %p unlocked after timeout",
entry);
}
/* reschedule if gst_poll_wait returned early or we have to reschedule after
* an unlock*/
real = GST_CLOCK_GET_CLASS (clock)->get_internal_time (clock);
now = gst_clock_adjust_unlocked (clock, real);
diff = entryt - now;
if (diff <= 0) {
/* timeout, this is fine, we can report success now */
entry->status = GST_CLOCK_OK;
GST_CAT_DEBUG (GST_CAT_CLOCK,
"entry %p finished, diff %" G_GINT64_FORMAT, entry, diff);
#ifdef WAIT_DEBUGGING
final = gst_system_clock_get_internal_time (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "Waited for %" G_GINT64_FORMAT
" got %" G_GINT64_FORMAT " diff %" G_GINT64_FORMAT
" %g target-offset %" G_GINT64_FORMAT " %g", entryt, now,
now - entryt,
(double) (GstClockTimeDiff) (now - entryt) / GST_SECOND,
(final - target),
((double) (GstClockTimeDiff) (final - target)) / GST_SECOND);
#endif
break;
} else {
GST_CAT_DEBUG (GST_CAT_CLOCK,
"entry %p restart, diff %" G_GINT64_FORMAT, entry, diff);
}
}
}
} else if (diff == 0) {
entry->status = GST_CLOCK_OK;
} else {
entry->status = GST_CLOCK_EARLY;
}
return entry->status;
}
static GstClockReturn
gst_system_clock_id_wait_jitter (GstClock * clock, GstClockEntry * entry,
GstClockTimeDiff * jitter)
{
GstClockReturn ret;
GST_OBJECT_LOCK (clock);
if (G_UNLIKELY (entry->status == GST_CLOCK_UNSCHEDULED))
goto was_unscheduled;
ret = gst_system_clock_id_wait_jitter_unlocked (clock, entry, jitter, TRUE);
GST_OBJECT_UNLOCK (clock);
return ret;
/* ERRORS */
was_unscheduled:
{
GST_OBJECT_UNLOCK (clock);
return GST_CLOCK_UNSCHEDULED;
}
}
/* Start the async clock thread. Must be called with the object lock
* held */
static gboolean
gst_system_clock_start_async (GstSystemClock * clock)
{
GError *error = NULL;
if (G_LIKELY (clock->thread != NULL))
return TRUE; /* Thread already running. Nothing to do */
clock->thread = g_thread_create ((GThreadFunc) gst_system_clock_async_thread,
clock, TRUE, &error);
if (G_UNLIKELY (error))
goto no_thread;
/* wait for it to spin up */
GST_CLOCK_WAIT (clock);
return TRUE;
/* ERRORS */
no_thread:
{
g_warning ("could not create async clock thread: %s", error->message);
g_error_free (error);
}
return FALSE;
}
/* Add an entry to the list of pending async waits. The entry is inserted
* in sorted order. If we inserted the entry at the head of the list, we
* need to signal the thread as it might either be waiting on it or waiting
* for a new entry.
*
* MT safe.
*/
static GstClockReturn
gst_system_clock_id_wait_async (GstClock * clock, GstClockEntry * entry)
{
GstSystemClock *sysclock;
GstClockEntry *head;
sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "adding async entry %p", entry);
GST_OBJECT_LOCK (clock);
/* Start the clock async thread if needed */
if (G_UNLIKELY (!gst_system_clock_start_async (sysclock)))
goto thread_error;
if (G_UNLIKELY (entry->status == GST_CLOCK_UNSCHEDULED))
goto was_unscheduled;
if (clock->entries)
head = clock->entries->data;
else
head = NULL;
/* need to take a ref */
gst_clock_id_ref ((GstClockID) entry);
/* insert the entry in sorted order */
clock->entries = g_list_insert_sorted (clock->entries, entry,
gst_clock_id_compare_func);
/* only need to send the signal if the entry was added to the
* front, else the thread is just waiting for another entry and
* will get to this entry automatically. */
if (clock->entries->data == entry) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "async entry added to head");
if (head == NULL) {
/* the list was empty before, signal the cond so that the async thread can
* start taking a look at the queue */
GST_CAT_DEBUG (GST_CAT_CLOCK, "first entry, sending signal");
GST_CLOCK_BROADCAST (clock);
} else {
if (head->status == GST_CLOCK_BUSY) {
/* the async thread was waiting for an entry, unlock the wait so that it
* looks at the new head entry instead, we only need to do this once */
if (!sysclock->priv->async_wakeup) {
GST_CAT_DEBUG (GST_CAT_CLOCK, "wakeup async thread");
sysclock->priv->async_wakeup = TRUE;
gst_system_clock_add_wakeup (sysclock);
}
}
}
}
GST_OBJECT_UNLOCK (clock);
return GST_CLOCK_OK;
/* ERRORS */
thread_error:
{
/* Could not start the async clock thread */
GST_OBJECT_UNLOCK (clock);
return GST_CLOCK_ERROR;
}
was_unscheduled:
{
GST_OBJECT_UNLOCK (clock);
return GST_CLOCK_UNSCHEDULED;
}
}
/* unschedule an entry. This will set the state of the entry to GST_CLOCK_UNSCHEDULED
* and will signal any thread waiting for entries to recheck their entry.
* We cannot really decide if the signal is needed or not because the entry
* could be waited on in async or sync mode.
*
* MT safe.
*/
static void
gst_system_clock_id_unschedule (GstClock * clock, GstClockEntry * entry)
{
GstSystemClock *sysclock;
sysclock = GST_SYSTEM_CLOCK_CAST (clock);
GST_CAT_DEBUG (GST_CAT_CLOCK, "unscheduling entry %p", entry);
GST_OBJECT_LOCK (clock);
if (entry->status == GST_CLOCK_BUSY) {
/* the entry was being busy, wake up all entries so that they recheck their
* status. We cannot wake up just one entry because allocating such a
* datastructure for each entry would be too heavy and unlocking an entry
* is usually done when shutting down or some other exceptional case. */
GST_CAT_DEBUG (GST_CAT_CLOCK, "entry was BUSY, doing wakeup");
gst_system_clock_add_wakeup (sysclock);
}
/* when it leaves the poll, it'll detect the unscheduled */
entry->status = GST_CLOCK_UNSCHEDULED;
GST_OBJECT_UNLOCK (clock);
}