gstreamer/gst/gstclock.c

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *
 * gstclock.c: Clock subsystem for maintaining time sync
 *
 * 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.
 */

#include <time.h>

#include "gst_private.h"

#include "gstclock.h"
#include "gstinfo.h"
#include "gstmemchunk.h"

#ifndef GST_DISABLE_TRACE
/* #define GST_WITH_ALLOC_TRACE */
#include "gsttrace.h"
static GstAllocTrace *_gst_clock_entry_trace;
#endif

#define DEFAULT_EVENT_DIFF	(GST_SECOND)
#define DEFAULT_MAX_DIFF	(2 * GST_SECOND)

enum
{
  ARG_0,
  ARG_STATS,
  ARG_MAX_DIFF,
  ARG_EVENT_DIFF
};

static GstMemChunk *_gst_clock_entries_chunk;

void gst_clock_id_unlock (GstClockID id);


static void gst_clock_class_init (GstClockClass * klass);
static void gst_clock_init (GstClock * clock);
static void gst_clock_dispose (GObject * object);

static void gst_clock_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_clock_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static void gst_clock_update_stats (GstClock * clock);


static GstObjectClass *parent_class = NULL;

/* static guint gst_clock_signals[LAST_SIGNAL] = { 0 }; */

static GstClockID
gst_clock_entry_new (GstClock * clock, GstClockTime time,
    GstClockTime interval, GstClockEntryType type)
{
  GstClockEntry *entry;

  entry = gst_mem_chunk_alloc (_gst_clock_entries_chunk);
#ifndef GST_DISABLE_TRACE
  gst_alloc_trace_new (_gst_clock_entry_trace, entry);
#endif

  entry->clock = clock;
  entry->time = time;
  entry->interval = interval;
  entry->type = type;
  entry->status = GST_CLOCK_ENTRY_OK;

  return (GstClockID) entry;
}

/**
 * gst_clock_new_single_shot_id
 * @clock: The clockid to get a single shot notification from
 * @time: the requested time
 *
 * Get an ID from the given clock to trigger a single shot 
 * notification at the requested time.
 *
 * Returns: An id that can be used to request the time notification.
 */
GstClockID
gst_clock_new_single_shot_id (GstClock * clock, GstClockTime time)
{
  g_return_val_if_fail (GST_IS_CLOCK (clock), NULL);

  return gst_clock_entry_new (clock,
      time, GST_CLOCK_TIME_NONE, GST_CLOCK_ENTRY_SINGLE);
}

/**
 * gst_clock_new_periodic_id
 * @clock: The clockid to get a periodic notification id from
 * @start_time: the requested start time
 * @interval: the requested interval
 *
 * Get an ID from the given clock to trigger a periodic notification.
 * The periodeic notifications will be start at time start_time and
 * will then be fired with the given interval.
 *
 * Returns: An id that can be used to request the time notification.
 */
GstClockID
gst_clock_new_periodic_id (GstClock * clock, GstClockTime start_time,
    GstClockTime interval)
{
  g_return_val_if_fail (GST_IS_CLOCK (clock), NULL);
  g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (start_time), NULL);
  g_return_val_if_fail (interval != 0, NULL);

  return gst_clock_entry_new (clock,
      start_time, interval, GST_CLOCK_ENTRY_PERIODIC);
}

/**
 * gst_clock_id_get_time
 * @id: The clockid to query
 *
 * Get the time of the clock ID
 *
 * Returns: the time of the given clock id
 */
GstClockTime
gst_clock_id_get_time (GstClockID id)
{
  g_return_val_if_fail (id != NULL, GST_CLOCK_TIME_NONE);

  return GST_CLOCK_ENTRY_TIME ((GstClockEntry *) id);
}


/**
 * gst_clock_id_wait
 * @id: The clockid to wait on
 * @jitter: A pointer that will contain the jitter
 *
 * Perform a blocking wait on the given ID. The jitter arg can be
 * NULL
 *
 * Returns: the result of the blocking wait.
 */
GstClockReturn
gst_clock_id_wait (GstClockID id, GstClockTimeDiff * jitter)
{
  GstClockEntry *entry;
  GstClock *clock;
  GstClockReturn res = GST_CLOCK_UNSUPPORTED;
  GstClockTime requested;
  GstClockClass *cclass;

  g_return_val_if_fail (id != NULL, GST_CLOCK_ERROR);

  entry = (GstClockEntry *) id;
  requested = GST_CLOCK_ENTRY_TIME (entry);

  if (!GST_CLOCK_TIME_IS_VALID (requested)) {
    GST_CAT_DEBUG (GST_CAT_CLOCK, "invalid time requested, returning _TIMEOUT");
    return GST_CLOCK_TIMEOUT;
  }

  clock = GST_CLOCK_ENTRY_CLOCK (entry);
  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->wait) {
    GstClockTime now;

    GST_LOCK (clock);
    clock->entries = g_list_prepend (clock->entries, entry);
    GST_UNLOCK (clock);

    GST_CAT_DEBUG (GST_CAT_CLOCK, "waiting on clock");
    do {
      res = cclass->wait (clock, entry);
    }
    while (res == GST_CLOCK_ENTRY_RESTART);
    GST_CAT_DEBUG (GST_CAT_CLOCK, "done waiting");

    GST_LOCK (clock);
    clock->entries = g_list_remove (clock->entries, entry);
    GST_UNLOCK (clock);

    if (jitter) {
      now = gst_clock_get_time (clock);
      *jitter = now - requested;
    }

    if (clock->stats) {
      gst_clock_update_stats (clock);
    }
  }

  return res;
}

/**
 * gst_clock_id_wait_async:
 * @id: a #GstClockID to wait on
 * @func: The callback function 
 * @user_data: User data passed in the calback
 *
 * Register a callback on the given clockid with the given
 * function and user_data.
 *
 * Returns: the result of the non blocking wait.
 */
GstClockReturn
gst_clock_id_wait_async (GstClockID id,
    GstClockCallback func, gpointer user_data)
{
  GstClockEntry *entry;
  GstClock *clock;
  GstClockReturn res = GST_CLOCK_UNSUPPORTED;
  GstClockClass *cclass;

  g_return_val_if_fail (id != NULL, GST_CLOCK_ERROR);
  g_return_val_if_fail (func != NULL, GST_CLOCK_ERROR);

  entry = (GstClockEntry *) id;
  clock = entry->clock;

  if (!GST_CLOCK_TIME_IS_VALID (GST_CLOCK_ENTRY_TIME (entry))) {
    (func) (clock, GST_CLOCK_TIME_NONE, id, user_data);
    return GST_CLOCK_TIMEOUT;
  }

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->wait_async) {
    entry->func = func;
    entry->user_data = user_data;

    res = cclass->wait_async (clock, entry);
  }

  return res;
}

static void
gst_clock_reschedule_func (GstClockEntry * entry)
{
  entry->status = GST_CLOCK_ENTRY_OK;

  gst_clock_id_unlock ((GstClockID) entry);
}

/**
 * gst_clock_id_unschedule:
 * @id: The id to unschedule
 *
 * Cancel an outstanding async notification request with the given ID.
 */
void
gst_clock_id_unschedule (GstClockID id)
{
  GstClockEntry *entry;
  GstClock *clock;
  GstClockClass *cclass;

  g_return_if_fail (id != NULL);

  entry = (GstClockEntry *) id;
  clock = entry->clock;

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->unschedule)
    cclass->unschedule (clock, entry);
}

/**
 * gst_clock_id_free:
 * @id: The clockid to free
 *
 * Free the resources held by the given id
 */
void
gst_clock_id_free (GstClockID id)
{
  g_return_if_fail (id != NULL);

#ifndef GST_DISABLE_TRACE
  gst_alloc_trace_free (_gst_clock_entry_trace, id);
#endif
  gst_mem_chunk_free (_gst_clock_entries_chunk, id);
}

/**
 * gst_clock_id_unlock:
 * @id: The clockid to unlock
 *
 * Unlock the givan ClockID.
 */
void
gst_clock_id_unlock (GstClockID id)
{
  GstClockEntry *entry;
  GstClock *clock;
  GstClockClass *cclass;

  g_return_if_fail (id != NULL);

  entry = (GstClockEntry *) id;
  clock = entry->clock;

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->unlock)
    cclass->unlock (clock, entry);
}


/**
 * GstClock abstract base class implementation
 */
GType
gst_clock_get_type (void)
{
  static GType clock_type = 0;

  if (!clock_type) {
    static const GTypeInfo clock_info = {
      sizeof (GstClockClass),
      NULL,
      NULL,
      (GClassInitFunc) gst_clock_class_init,
      NULL,
      NULL,
      sizeof (GstClock),
      0,
      (GInstanceInitFunc) gst_clock_init,
      NULL
    };

    clock_type = g_type_register_static (GST_TYPE_OBJECT, "GstClock",
        &clock_info, G_TYPE_FLAG_ABSTRACT);
  }
  return clock_type;
}

static void
gst_clock_class_init (GstClockClass * klass)
{
  GObjectClass *gobject_class;
  GstObjectClass *gstobject_class;

  gobject_class = (GObjectClass *) klass;
  gstobject_class = (GstObjectClass *) klass;

  parent_class = g_type_class_ref (GST_TYPE_OBJECT);

  if (!g_thread_supported ())
    g_thread_init (NULL);

  _gst_clock_entries_chunk = gst_mem_chunk_new ("GstClockEntries",
      sizeof (GstClockEntry), sizeof (GstClockEntry) * 32, G_ALLOC_AND_FREE);

#ifndef GST_DISABLE_TRACE
  _gst_clock_entry_trace =
      gst_alloc_trace_register (GST_CLOCK_ENTRY_TRACE_NAME);
#endif

  gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_clock_dispose);
  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_clock_set_property);
  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_clock_get_property);

  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_STATS,
      g_param_spec_boolean ("stats", "Stats", "Enable clock stats",
          FALSE, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_MAX_DIFF,
      g_param_spec_int64 ("max-diff", "Max diff",
          "The maximum amount of time to wait in nanoseconds", 0, G_MAXINT64,
          DEFAULT_MAX_DIFF, G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_EVENT_DIFF,
      g_param_spec_uint64 ("event-diff", "event diff",
          "The amount of time that may elapse until 2 events are treated as happening at different times",
          0, G_MAXUINT64, DEFAULT_EVENT_DIFF,
          G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
}

static void
gst_clock_init (GstClock * clock)
{
  clock->max_diff = DEFAULT_MAX_DIFF;

  clock->start_time = 0;
  clock->last_time = 0;
  clock->entries = NULL;
  clock->flags = 0;
  clock->stats = FALSE;

  clock->active_mutex = g_mutex_new ();
  clock->active_cond = g_cond_new ();
}

static void
gst_clock_dispose (GObject * object)
{
  GstClock *clock = GST_CLOCK (object);

  g_mutex_free (clock->active_mutex);
  g_cond_free (clock->active_cond);

  G_OBJECT_CLASS (parent_class)->dispose (object);
}

/**
 * gst_clock_set_speed
 * @clock: a #GstClock to modify
 * @speed: the speed to set on the clock
 *
 * Sets the speed on the given clock. 1.0 is the default 
 * speed.
 *
 * Returns: the new speed of the clock.
 */
gdouble
gst_clock_set_speed (GstClock * clock, gdouble speed)
{
  g_return_val_if_fail (GST_IS_CLOCK (clock), 0.0);

  GST_WARNING_OBJECT (clock, "called deprecated function");
  return 1.0;
}

/**
 * gst_clock_get_speed
 * @clock: a #GstClock to query
 *
 * Gets the speed of the given clock.
 *
 * Returns: the speed of the clock.
 */
gdouble
gst_clock_get_speed (GstClock * clock)
{
  g_return_val_if_fail (GST_IS_CLOCK (clock), 0.0);

  GST_WARNING_OBJECT (clock, "called deprecated function");
  return 1.0;
}

/**
 * gst_clock_set_resolution
 * @clock: The clock set the resolution on
 * @resolution: The resolution to set
 *
 * Set the accuracy of the clock.
 *
 * Returns: the new resolution of the clock.
 */
guint64
gst_clock_set_resolution (GstClock * clock, guint64 resolution)
{
  GstClockClass *cclass;

  g_return_val_if_fail (GST_IS_CLOCK (clock), G_GINT64_CONSTANT (0));
  g_return_val_if_fail (resolution != 0, G_GINT64_CONSTANT (0));

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->change_resolution)
    clock->resolution =
        cclass->change_resolution (clock, clock->resolution, resolution);

  return clock->resolution;
}

/**
 * gst_clock_get_resolution
 * @clock: The clock get the resolution of
 *
 * Get the accuracy of the clock.
 *
 * Returns: the resolution of the clock in microseconds.
 */
guint64
gst_clock_get_resolution (GstClock * clock)
{
  GstClockClass *cclass;

  g_return_val_if_fail (GST_IS_CLOCK (clock), G_GINT64_CONSTANT (0));

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->get_resolution)
    return cclass->get_resolution (clock);

  return G_GINT64_CONSTANT (1);
}

/**
 * gst_clock_set_active
 * @clock: a #GstClock to set state of
 * @active: flag indicating if the clock should be activated (TRUE) or deactivated
 *
 * Activates or deactivates the clock based on the active parameter.
 * As soon as the clock is activated, the time will start ticking.
 */
void
gst_clock_set_active (GstClock * clock, gboolean active)
{
  g_return_if_fail (GST_IS_CLOCK (clock));

  GST_ERROR_OBJECT (clock, "called deprecated function that does nothing now.");

  return;
}

/**
 * gst_clock_is_active
 * @clock: a #GstClock to query
 *
 * Checks if the given clock is active.
 * 
 * Returns: TRUE if the clock is active.
 */
gboolean
gst_clock_is_active (GstClock * clock)
{
  g_return_val_if_fail (GST_IS_CLOCK (clock), FALSE);

  GST_WARNING_OBJECT (clock, "called deprecated function.");

  return TRUE;
}

/**
 * gst_clock_reset
 * @clock: a #GstClock to reset
 *
 * Reset the clock to time 0.
 */
void
gst_clock_reset (GstClock * clock)
{
  GstClockTime time = G_GINT64_CONSTANT (0);
  GstClockClass *cclass;

  g_return_if_fail (GST_IS_CLOCK (clock));

  GST_ERROR_OBJECT (clock, "called deprecated function.");

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->get_internal_time) {
    time = cclass->get_internal_time (clock);
  }

  GST_LOCK (clock);
  //clock->active = FALSE;
  clock->start_time = time;
  clock->last_time = G_GINT64_CONSTANT (0);
  g_list_foreach (clock->entries, (GFunc) gst_clock_reschedule_func, NULL);
  GST_UNLOCK (clock);
}

/**
 * gst_clock_handle_discont
 * @clock: a #GstClock to notify of the discontinuity
 * @time: The new time
 *
 * Notifies the clock of a discontinuity in time.
 *
 * Returns: TRUE if the clock was updated. It is possible that
 * the clock was not updated by this call because only the first
 * discontinuitity in the pipeline is honoured.
 */
gboolean
gst_clock_handle_discont (GstClock * clock, guint64 time)
{
  GST_ERROR_OBJECT (clock, "called deprecated function.");

  return FALSE;
}

/**
 * gst_clock_get_time
 * @clock: a #GstClock to query
 *
 * Gets the current time of the given clock. The time is always
 * monotonically increasing.
 *
 * Returns: the time of the clock.
 */
GstClockTime
gst_clock_get_time (GstClock * clock)
{
  GstClockTime ret = G_GINT64_CONSTANT (0);
  GstClockClass *cclass;

  g_return_val_if_fail (GST_IS_CLOCK (clock), G_GINT64_CONSTANT (0));

  cclass = GST_CLOCK_GET_CLASS (clock);

  if (cclass->get_internal_time) {
    ret = cclass->get_internal_time (clock) - clock->start_time;
  }
  /* make sure the time is increasing, else return last_time */
  if ((gint64) ret < (gint64) clock->last_time) {
    ret = clock->last_time;
  } else {
    clock->last_time = ret;
  }

  return ret;
}

/**
 * gst_clock_get_event_time:
 * @clock: clock to query
 * 
 * Gets the "event time" of a given clock. An event on the clock happens
 * whenever this function is called. This ensures that multiple events that
 * happen shortly after each other are treated as if they happened at the same
 * time. GStreamer uses to keep state changes of multiple elements in sync.
 *
 * Returns: the time of the event
 */
GstClockTime
gst_clock_get_event_time (GstClock * clock)
{
  return gst_clock_get_event_time_delay (clock, 0);
}

/**
 * gst_clock_get_event_time_delay:
 * @clock: clock to query
 * @delay: time before the event actually occurs
 *
 * Gets the "event time" of a given clock. An event on the clock happens
 * whenever this function is called. This ensures that multiple events that
 * happen shortly after each other are treated as if they happened at the same
 * time. GStreamer uses to keep state changes of multiple elements in sync.
 *
 * When calling this function, the specified delay will be added to the current
 * time to produce the event time. This can be used for events that are
 * scheduled to happen at some point in the future.
 *
 * Returns: the time of the event
 */
GstClockTime
gst_clock_get_event_time_delay (GstClock * clock, GstClockTime delay)
{
  GstClockTime time;

  g_return_val_if_fail (GST_IS_CLOCK (clock), GST_CLOCK_TIME_NONE);

  time = gst_clock_get_time (clock);

  if (ABS (GST_CLOCK_DIFF (clock->last_event, time + delay)) <
      clock->max_event_diff) {
    GST_LOG_OBJECT (clock, "reporting last event time %" G_GUINT64_FORMAT,
        clock->last_event);
  } else {
    clock->last_event = time + delay;
    GST_LOG_OBJECT (clock, "reporting new event time %" G_GUINT64_FORMAT,
        clock->last_event);
  }

  return clock->last_event;
}

/**
 * gst_clock_get_next_id
 * @clock: The clock to query
 *
 * Get the clockid of the next event.
 *
 * Returns: a clockid or NULL is no event is pending.
 */
GstClockID
gst_clock_get_next_id (GstClock * clock)
{
  GstClockEntry *entry = NULL;

  g_return_val_if_fail (GST_IS_CLOCK (clock), NULL);

  GST_LOCK (clock);
  if (clock->entries)
    entry = GST_CLOCK_ENTRY (clock->entries->data);
  GST_UNLOCK (clock);

  return (GstClockID *) entry;
}

static void
gst_clock_update_stats (GstClock * clock)
{
}

static void
gst_clock_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstClock *clock;

  clock = GST_CLOCK (object);

  switch (prop_id) {
    case ARG_STATS:
      clock->stats = g_value_get_boolean (value);
      g_object_notify (object, "stats");
      break;
    case ARG_MAX_DIFF:
      clock->max_diff = g_value_get_int64 (value);
      g_object_notify (object, "max-diff");
      break;
    case ARG_EVENT_DIFF:
      clock->max_event_diff = g_value_get_uint64 (value);
      g_object_notify (object, "event-diff");
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_clock_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstClock *clock;

  clock = GST_CLOCK (object);

  switch (prop_id) {
    case ARG_STATS:
      g_value_set_boolean (value, clock->stats);
      break;
    case ARG_MAX_DIFF:
      g_value_set_int64 (value, clock->max_diff);
      break;
    case ARG_EVENT_DIFF:
      g_value_set_uint64 (value, clock->max_event_diff);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}