/* GStreamer2
 * Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
 *
 * threadscheduler.c: scheduler using threads 
 *
 * 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.
 */

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

#include <gst/gst.h>
#include "../gst-i18n-lib.h"

GST_DEBUG_CATEGORY_STATIC (debug_scheduler);
#define GST_CAT_DEFAULT debug_scheduler

#define GST_TYPE_THREAD_SCHEDULER \
  (gst_thread_scheduler_get_type ())
#define GST_THREAD_SCHEDULER(obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_THREAD_SCHEDULER,GstThreadScheduler))
#define GST_THREAD_SCHEDULER_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_THREAD_SCHEDULER,GstThreadSchedulerClass))
#define GST_IS_THREAD_SCHEDULER(obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_THREAD_SCHEDULER))
#define GST_IS_THREAD_SCHEDULER_CLASS(obj) \
  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_THREAD_SCHEDULER))

#define SCHED(element) (GST_THREAD_SCHEDULER ((element)->sched))

GType gst_thread_scheduler_get_type (void);

typedef struct _GstThreadScheduler GstThreadScheduler;
typedef struct _GstThreadSchedulerClass GstThreadSchedulerClass;

struct _GstThreadScheduler
{
  GstScheduler scheduler;

  GThreadPool *pool;
};

struct _GstThreadSchedulerClass
{
  GstSchedulerClass scheduler_class;
};

#define ELEMENT_PRIVATE(element) GST_ELEMENT (element)->sched_private
#define PAD_PRIVATE(pad) (GST_REAL_PAD (pad))->sched_private

#define GST_TYPE_THREAD_SCHEDULER_TASK \
  (gst_thread_scheduler_task_get_type ())
#define GST_THREAD_SCHEDULER_TASK(obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_THREAD_SCHEDULER_TASK,GstThreadSchedulerTask))
#define GST_THREAD_SCHEDULER_TASK_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_THREAD_SCHEDULER_TASK,GstThreadSchedulerTaskClass))
#define GST_IS_THREAD_SCHEDULER_TASK(obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_THREAD_SCHEDULER_TASK))
#define GST_IS_THREAD_SCHEDULER_TASK_CLASS(obj) \
  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_THREAD_SCHEDULER_TASK))

typedef struct _GstThreadSchedulerTask GstThreadSchedulerTask;
typedef struct _GstThreadSchedulerTaskClass GstThreadSchedulerTaskClass;

struct _GstThreadSchedulerTask
{
  GstTask task;
};

struct _GstThreadSchedulerTaskClass
{
  GstTaskClass parent_class;
};

static void gst_thread_scheduler_task_class_init (gpointer g_class,
    gpointer data);
static void gst_thread_scheduler_task_init (GstThreadSchedulerTask * object);

static gboolean gst_thread_scheduler_task_start (GstTask * task);
static gboolean gst_thread_scheduler_task_stop (GstTask * task);
static gboolean gst_thread_scheduler_task_pause (GstTask * task);

GType
gst_thread_scheduler_task_get_type (void)
{
  static GType object_type = 0;

  if (object_type == 0) {
    static const GTypeInfo object_info = {
      sizeof (GstThreadSchedulerTaskClass),
      NULL,
      NULL,
      gst_thread_scheduler_task_class_init,
      NULL,
      NULL,
      sizeof (GstThreadSchedulerTask),
      0,
      (GInstanceInitFunc) gst_thread_scheduler_task_init
    };

    object_type =
        g_type_register_static (GST_TYPE_TASK,
        "GstThreadSchedulerTask", &object_info, 0);
  }
  return object_type;
}

static void
gst_thread_scheduler_task_class_init (gpointer klass, gpointer class_data)
{
  GstTaskClass *task = GST_TASK_CLASS (klass);

  task->start = gst_thread_scheduler_task_start;
  task->stop = gst_thread_scheduler_task_stop;
  task->pause = gst_thread_scheduler_task_pause;
}

static void
gst_thread_scheduler_task_init (GstThreadSchedulerTask * task)
{
  GST_TASK (task)->state = GST_TASK_STOPPED;
}

static gboolean
gst_thread_scheduler_task_start (GstTask * task)
{
  GstThreadSchedulerTask *ttask = GST_THREAD_SCHEDULER_TASK (task);
  GstThreadScheduler *tsched =
      GST_THREAD_SCHEDULER (GST_OBJECT_PARENT (GST_OBJECT (task)));
  GstTaskState old;
  GStaticRecMutex *lock;

  GST_DEBUG_OBJECT (task, "Starting task %p", task);

  if ((lock = GST_TASK_GET_LOCK (task)) == NULL) {
    lock = g_new (GStaticRecMutex, 1);
    g_static_rec_mutex_init (lock);
    GST_TASK_GET_LOCK (task) = lock;
  }

  GST_LOCK (ttask);
  old = GST_TASK_CAST (ttask)->state;
  GST_TASK_CAST (ttask)->state = GST_TASK_STARTED;
  switch (old) {
    case GST_TASK_STOPPED:
      gst_object_ref (GST_OBJECT (task));
      g_thread_pool_push (tsched->pool, task, NULL);
      break;
    case GST_TASK_PAUSED:
      GST_TASK_SIGNAL (ttask);
      break;
    case GST_TASK_STARTED:
      break;
  }
  GST_UNLOCK (ttask);

  return TRUE;
}

static gboolean
gst_thread_scheduler_task_stop (GstTask * task)
{
  GstThreadSchedulerTask *ttask = GST_THREAD_SCHEDULER_TASK (task);
  GstTaskState old;

  GST_DEBUG_OBJECT (task, "Stopping task %p", task);

  GST_LOCK (ttask);
  old = GST_TASK_CAST (ttask)->state;
  GST_TASK_CAST (ttask)->state = GST_TASK_STOPPED;
  switch (old) {
    case GST_TASK_STOPPED:
      break;
    case GST_TASK_PAUSED:
      GST_TASK_SIGNAL (ttask);
      break;
    case GST_TASK_STARTED:
      break;
  }
  GST_UNLOCK (ttask);

  return TRUE;
}

static gboolean
gst_thread_scheduler_task_pause (GstTask * task)
{
  GstThreadSchedulerTask *ttask = GST_THREAD_SCHEDULER_TASK (task);
  GstThreadScheduler *tsched =
      GST_THREAD_SCHEDULER (GST_OBJECT_PARENT (GST_OBJECT (task)));
  GstTaskState old;

  GST_DEBUG_OBJECT (task, "Pausing task %p", task);

  GST_LOCK (ttask);
  old = GST_TASK_CAST (ttask)->state;
  GST_TASK_CAST (ttask)->state = GST_TASK_PAUSED;
  switch (old) {
    case GST_TASK_STOPPED:
      gst_object_ref (GST_OBJECT (task));
      g_thread_pool_push (tsched->pool, task, NULL);
      break;
    case GST_TASK_PAUSED:
      break;
    case GST_TASK_STARTED:
      break;
  }
  GST_UNLOCK (ttask);

  return TRUE;
}

static void gst_thread_scheduler_class_init (gpointer g_class, gpointer data);
static void gst_thread_scheduler_init (GstThreadScheduler * object);

GType
gst_thread_scheduler_get_type (void)
{
  static GType object_type = 0;

  if (object_type == 0) {
    static const GTypeInfo object_info = {
      sizeof (GstThreadSchedulerClass),
      NULL,
      NULL,
      gst_thread_scheduler_class_init,
      NULL,
      NULL,
      sizeof (GstThreadScheduler),
      0,
      (GInstanceInitFunc) gst_thread_scheduler_init
    };

    object_type =
        g_type_register_static (GST_TYPE_SCHEDULER,
        "GstThreadScheduler", &object_info, 0);
  }
  return object_type;
}

static void gst_thread_scheduler_setup (GstScheduler * sched);
static void gst_thread_scheduler_reset (GstScheduler * sched);
static GstTask *gst_thread_scheduler_create_task (GstScheduler * sched,
    GstTaskFunction func, gpointer data);

static void
gst_thread_scheduler_class_init (gpointer klass, gpointer class_data)
{
  GstSchedulerClass *scheduler = GST_SCHEDULER_CLASS (klass);

  scheduler->setup = gst_thread_scheduler_setup;
  scheduler->reset = gst_thread_scheduler_reset;
  scheduler->create_task = gst_thread_scheduler_create_task;
}

static void
gst_thread_scheduler_func (GstThreadSchedulerTask * ttask,
    GstThreadScheduler * sched)
{
  GstTask *task = GST_TASK (ttask);

  GST_DEBUG_OBJECT (sched, "Entering task %p, thread %p", task,
      g_thread_self ());

  /* locking order is TASK_LOCK, LOCK */
  GST_TASK_LOCK (task);
  GST_LOCK (task);
  while (G_LIKELY (task->state != GST_TASK_STOPPED)) {
    while (G_UNLIKELY (task->state == GST_TASK_PAUSED)) {
      GST_TASK_UNLOCK (task);
      GST_TASK_SIGNAL (task);
      GST_TASK_WAIT (task);
      GST_UNLOCK (task);
      /* locking order.. */
      GST_TASK_LOCK (task);
      GST_LOCK (task);
      if (task->state == GST_TASK_STOPPED)
        goto done;
    }
    GST_UNLOCK (task);

    task->func (task->data);

    GST_LOCK (task);
  }
done:
  GST_UNLOCK (task);
  GST_TASK_UNLOCK (task);

  GST_DEBUG_OBJECT (sched, "Exit task %p, thread %p", task, g_thread_self ());

  gst_object_unref (GST_OBJECT (task));
}

static void
gst_thread_scheduler_init (GstThreadScheduler * scheduler)
{
  scheduler->pool = g_thread_pool_new (
      (GFunc) gst_thread_scheduler_func, scheduler, -1, FALSE, NULL);
}

static GstTask *
gst_thread_scheduler_create_task (GstScheduler * sched, GstTaskFunction func,
    gpointer data)
{
  GstThreadSchedulerTask *task;

  task =
      GST_THREAD_SCHEDULER_TASK (g_object_new (GST_TYPE_THREAD_SCHEDULER_TASK,
          NULL));
  gst_object_set_parent (GST_OBJECT (task), GST_OBJECT (sched));
  GST_TASK_CAST (task)->func = func;
  GST_TASK_CAST (task)->data = data;

  GST_DEBUG_OBJECT (sched, "Created task %p", task);

  return GST_TASK_CAST (task);
}

static void
gst_thread_scheduler_setup (GstScheduler * sched)
{
}

static void
gst_thread_scheduler_reset (GstScheduler * sched)
{
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  GstSchedulerFactory *factory;

  GST_DEBUG_CATEGORY_INIT (debug_scheduler, "thread", 0, "thread scheduler");

  factory = gst_scheduler_factory_new ("thread",
      "A scheduler using threads", GST_TYPE_THREAD_SCHEDULER);
  if (factory == NULL)
    return FALSE;

  gst_plugin_add_feature (plugin, GST_PLUGIN_FEATURE (factory));
  return TRUE;
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR, "gstthreadscheduler",
    "a thread scheduler", plugin_init, VERSION, GST_LICENSE, GST_PACKAGE,
    GST_ORIGIN)