gstnetclientclock.c

gnash 在pc和嵌入式下开发需要的源码

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <[e-mail]>
 *                    2005 Wim Taymans <[e-mail]>
 *                    2005 Andy Wingo <[e-mail]>
 *
 * gstnetclientclock.h: clock that synchronizes itself to a time provider over
 * the network
 *
 * 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:gstnetclientclock
 * @short_description: Special clock that synchronizes to a remote time
 *                     provider.
 * @see_also: #GstClock, #GstNetTimeProvider, #GstPipeline
 *
 * This object implements a custom #GstClock that synchronizes its time
 * to a remote time provider such as #GstNetTimeProvider.
 *
 * A new clock is created with gst_net_client_clock_new() which takes the
 * address and port of the remote time provider along with a name and
 * an initial time.
 *
 * This clock will poll the time provider and will update its calibration
 * parameters based on the local and remote observations.
 *
 * Various parameters of the clock can be configured with the parent #GstClock
 * "timeout", "window-size" and "window-threshold" object properties.
 *
 * A #GstNetClientClock is typically set on a #GstPipeline with 
 * gst_pipeline_use_clock().
 *
 * Last reviewed on 2005-11-23 (0.9.5)
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gstnettimepacket.h"
#include "gstnetclientclock.h"

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#if defined (_MSC_VER) && _MSC_VER >= 1400
#include <io.h>
#endif

GST_DEBUG_CATEGORY_STATIC (ncc_debug);
#define GST_CAT_DEFAULT (ncc_debug)

/* the select call is also performed on the control sockets, that way
 * we can send special commands to unblock or restart the select call */
#define CONTROL_RESTART        'R'      /* restart the select call */
#define CONTROL_STOP           'S'      /* stop the select call */
#define CONTROL_SOCKETS(self)   self->control_sock
#define WRITE_SOCKET(self)      self->control_sock[1]
#define READ_SOCKET(self)       self->control_sock[0]

#define SEND_COMMAND(self, command)                     \
G_STMT_START {                                  \
  unsigned char c; c = command;                 \
  write (WRITE_SOCKET(self), &c, 1);            \
} G_STMT_END

#define READ_COMMAND(self, command, res)                \
G_STMT_START {                                  \
  res = read(READ_SOCKET(self), &command, 1);    \
} G_STMT_END

#define DEFAULT_ADDRESS         "127.0.0.1"
#define DEFAULT_PORT            5637
#define DEFAULT_TIMEOUT         GST_SECOND

#ifdef G_OS_WIN32
#define getsockname(sock,addr,len) getsockname(sock,addr,(int *)len)
#endif

enum
{
  PROP_0,
  PROP_ADDRESS,
  PROP_PORT,
};

#define _do_init(type) \
  GST_DEBUG_CATEGORY_INIT (ncc_debug, "netclock", 0, "Network client clock");

GST_BOILERPLATE_FULL (GstNetClientClock, gst_net_client_clock,
    GstSystemClock, GST_TYPE_SYSTEM_CLOCK, _do_init);

static void gst_net_client_clock_finalize (GObject * object);
static void gst_net_client_clock_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_net_client_clock_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

static void gst_net_client_clock_stop (GstNetClientClock * self);

#ifdef G_OS_WIN32
static int
inet_aton (const char *c, struct in_addr *paddr)
{
  /* note that inet_addr is deprecated on unix because
   * inet_addr returns -1 (INADDR_NONE) for the valid 255.255.255.255
   * address. */
  paddr->s_addr = inet_addr (c);
  if (paddr->s_addr == INADDR_NONE)
    return 0;

  return 1;
}
#endif

static void
gst_net_client_clock_base_init (gpointer g_class)
{
  /* nop */
}

static void
gst_net_client_clock_class_init (GstNetClientClockClass * klass)
{
  GObjectClass *gobject_class;

  gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->finalize = gst_net_client_clock_finalize;
  gobject_class->get_property = gst_net_client_clock_get_property;
  gobject_class->set_property = gst_net_client_clock_set_property;

  g_object_class_install_property (gobject_class, PROP_ADDRESS,
      g_param_spec_string ("address", "address",
          "The address of the machine providing a time server, "
          "as a dotted quad (x.x.x.x)", DEFAULT_ADDRESS, G_PARAM_READWRITE));
  g_object_class_install_property (gobject_class, PROP_PORT,
      g_param_spec_int ("port", "port",
          "The port on which the remote server is listening", 0, G_MAXUINT16,
          DEFAULT_PORT, G_PARAM_READWRITE));
}

static void
gst_net_client_clock_init (GstNetClientClock * self,
    GstNetClientClockClass * g_class)
{
  GstClock *clock = GST_CLOCK_CAST (self);

#ifdef G_OS_WIN32
  WSADATA w;
  int error = WSAStartup (0x0202, &w);

  if (error) {
    GST_DEBUG_OBJECT (self, "Error on WSAStartup");
  }
  if (w.wVersion != 0x0202) {
    WSACleanup ();
  }
#endif

  self->port = DEFAULT_PORT;
  self->address = g_strdup (DEFAULT_ADDRESS);

  clock->timeout = DEFAULT_TIMEOUT;

  self->sock = -1;
  self->thread = NULL;

  self->servaddr = NULL;

  READ_SOCKET (self) = -1;
  WRITE_SOCKET (self) = -1;
}

static void
gst_net_client_clock_finalize (GObject * object)
{
  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);

  if (self->thread) {
    gst_net_client_clock_stop (self);
    g_assert (self->thread == NULL);
  }

  if (READ_SOCKET (self) != -1) {
    close (READ_SOCKET (self));
    close (WRITE_SOCKET (self));
    READ_SOCKET (self) = -1;
    WRITE_SOCKET (self) = -1;
  }

  g_free (self->address);
  self->address = NULL;

  g_free (self->servaddr);
  self->servaddr = NULL;

#ifdef G_OS_WIN32
  WSACleanup ();
#endif

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

static void
gst_net_client_clock_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);

  switch (prop_id) {
    case PROP_ADDRESS:
      g_free (self->address);
      if (g_value_get_string (value) == NULL)
        self->address = g_strdup (DEFAULT_ADDRESS);
      else
        self->address = g_strdup (g_value_get_string (value));
      break;
    case PROP_PORT:
      self->port = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_net_client_clock_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);

  switch (prop_id) {
    case PROP_ADDRESS:
      g_value_set_string (value, self->address);
      break;
    case PROP_PORT:
      g_value_set_int (value, self->port);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_net_client_clock_observe_times (GstNetClientClock * self,
    GstClockTime local_1, GstClockTime remote, GstClockTime local_2)
{
  GstClockTime local_avg;
  gdouble r_squared;
  GstClock *clock;

  if (local_2 < local_1)
    goto bogus_observation;

  local_avg = (local_2 + local_1) / 2;

  clock = GST_CLOCK_CAST (self);

  gst_clock_add_observation (GST_CLOCK (self), local_avg, remote, &r_squared);

  GST_CLOCK_SLAVE_LOCK (self);
  if (clock->filling) {
    self->current_timeout = 0;
  } else {
    /* geto formula */
    self->current_timeout =
        (1e-3 / (1 - MIN (r_squared, 0.99999))) * GST_SECOND;
    self->current_timeout = MIN (self->current_timeout, clock->timeout);
  }
  GST_CLOCK_SLAVE_UNLOCK (clock);

  return;

bogus_observation:
  {
    GST_WARNING_OBJECT (self, "time packet receive time < send time (%"
        GST_TIME_FORMAT " < %" GST_TIME_FORMAT ")", GST_TIME_ARGS (local_1),
        GST_TIME_ARGS (local_2));
    return;
  }
}

static gint
gst_net_client_clock_do_select (GstNetClientClock * self, fd_set * readfds)
{
  gint max_sock;
  gint ret;

  while (TRUE) {
    FD_ZERO (readfds);
    FD_SET (self->sock, readfds);
    FD_SET (READ_SOCKET (self), readfds);
    max_sock = MAX (self->sock, READ_SOCKET (self));

    GST_LOG_OBJECT (self, "doing select");
    {
      GstClockTime diff;
      GTimeVal tv, *ptv = &tv;

      diff = gst_clock_get_internal_time (GST_CLOCK (self));
      GST_TIME_TO_TIMEVAL (self->current_timeout, tv);

#ifdef G_OS_WIN32
      if (((max_sock + 1) != READ_SOCKET (self)) ||
          ((max_sock + 1) != WRITE_SOCKET (self))) {
        ret =
            select (max_sock + 1, readfds, NULL, NULL, (struct timeval *) ptv);
      } else {