* gst_task_set_lock().
*
* The task can be started, paused and stopped with gst_task_start(), gst_task_pause()
- * and gst_task_stop() respectively.
+ * and gst_task_stop() respectively or with the gst_task_set_state() function.
*
- * A #GstTask will repeadedly call the #GstTaskFunction with the user data
- * that was provided when creating the task with gst_task_create(). Before calling
- * the function it will acquire the provided lock.
+ * A #GstTask will repeatedly call the #GstTaskFunction with the user data
+ * that was provided when creating the task with gst_task_create(). While calling
+ * the function it will acquire the provided lock. The provided lock is released
+ * when the task pauses or stops.
*
- * Stopping a task with gst_task_stop() will not immediatly make sure the task is
+ * Stopping a task with gst_task_stop() will not immediately make sure the task is
* not running anymore. Use gst_task_join() to make sure the task is completely
* stopped and the thread is stopped.
*
GST_DEBUG_CATEGORY_STATIC (task_debug);
#define GST_CAT_DEFAULT (task_debug)
+#define GST_TASK_GET_PRIVATE(obj) \
+ (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_TASK, GstTaskPrivate))
+
+struct _GstTaskPrivate
+{
+ /* callbacks for managing the thread of this task */
+ GstTaskThreadCallbacks thr_callbacks;
+ gpointer thr_user_data;
+ GDestroyNotify thr_notify;
+
+ gboolean prio_set;
+ GThreadPriority priority;
+
+ /* configured pool */
+ GstTaskPool *pool;
+
+ /* remember the pool and id that is currently running. */
+ gpointer id;
+ GstTaskPool *pool_id;
+};
+
static void gst_task_class_init (GstTaskClass * klass);
static void gst_task_init (GstTask * task);
static void gst_task_finalize (GObject * object);
-static void gst_task_func (GstTask * task, GstTaskClass * tclass);
-
-static GstObjectClass *parent_class = NULL;
+static void gst_task_func (GstTask * task);
static GStaticMutex pool_lock = G_STATIC_MUTEX_INIT;
-GType
-gst_task_get_type (void)
+#define _do_init \
+{ \
+ GST_DEBUG_CATEGORY_INIT (task_debug, "task", 0, "Processing tasks"); \
+}
+
+G_DEFINE_TYPE_WITH_CODE (GstTask, gst_task, GST_TYPE_OBJECT, _do_init);
+
+static void
+init_klass_pool (GstTaskClass * klass)
{
- static GType _gst_task_type = 0;
-
- if (G_UNLIKELY (_gst_task_type == 0)) {
- static const GTypeInfo task_info = {
- sizeof (GstTaskClass),
- NULL,
- NULL,
- (GClassInitFunc) gst_task_class_init,
- NULL,
- NULL,
- sizeof (GstTask),
- 0,
- (GInstanceInitFunc) gst_task_init,
- NULL
- };
-
- _gst_task_type =
- g_type_register_static (GST_TYPE_OBJECT, "GstTask", &task_info, 0);
-
- GST_DEBUG_CATEGORY_INIT (task_debug, "task", 0, "Processing tasks");
+ g_static_mutex_lock (&pool_lock);
+ if (klass->pool) {
+ gst_task_pool_cleanup (klass->pool);
+ gst_object_unref (klass->pool);
}
- return _gst_task_type;
+ klass->pool = gst_task_pool_new ();
+ gst_task_pool_prepare (klass->pool, NULL);
+ g_static_mutex_unlock (&pool_lock);
}
static void
gobject_class = (GObjectClass *) klass;
- parent_class = g_type_class_ref (GST_TYPE_OBJECT);
+ g_type_class_add_private (klass, sizeof (GstTaskPrivate));
- gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_task_finalize);
+ gobject_class->finalize = gst_task_finalize;
- klass->pool = g_thread_pool_new (
- (GFunc) gst_task_func, klass, -1, FALSE, NULL);
+ init_klass_pool (klass);
}
static void
gst_task_init (GstTask * task)
{
+ GstTaskClass *klass;
+
+ klass = GST_TASK_GET_CLASS (task);
+
+ task->priv = GST_TASK_GET_PRIVATE (task);
task->running = FALSE;
task->abidata.ABI.thread = NULL;
task->lock = NULL;
task->cond = g_cond_new ();
task->state = GST_TASK_STOPPED;
+ task->priv->prio_set = FALSE;
+
+ /* use the default klass pool for this task, users can
+ * override this later */
+ g_static_mutex_lock (&pool_lock);
+ task->priv->pool = gst_object_ref (klass->pool);
+ g_static_mutex_unlock (&pool_lock);
}
static void
gst_task_finalize (GObject * object)
{
GstTask *task = GST_TASK (object);
+ GstTaskPrivate *priv = task->priv;
GST_DEBUG ("task %p finalize", task);
+ if (priv->thr_notify)
+ priv->thr_notify (priv->thr_user_data);
+ priv->thr_notify = NULL;
+ priv->thr_user_data = NULL;
+
+ gst_object_unref (priv->pool);
+
/* task thread cannot be running here since it holds a ref
* to the task so that the finalize could not have happened */
g_cond_free (task->cond);
task->cond = NULL;
- G_OBJECT_CLASS (parent_class)->finalize (object);
+ G_OBJECT_CLASS (gst_task_parent_class)->finalize (object);
}
static void
-gst_task_func (GstTask * task, GstTaskClass * tclass)
+gst_task_func (GstTask * task)
{
GStaticRecMutex *lock;
GThread *tself;
+ GstTaskPrivate *priv;
+
+ priv = task->priv;
tself = g_thread_self ();
lock = GST_TASK_GET_LOCK (task);
if (G_UNLIKELY (lock == NULL))
goto no_lock;
- task->running = TRUE;
task->abidata.ABI.thread = tself;
+ /* only update the priority when it was changed */
+ if (priv->prio_set)
+ g_thread_set_priority (tself, priv->priority);
GST_OBJECT_UNLOCK (task);
+ /* fire the enter_thread callback when we need to */
+ if (priv->thr_callbacks.enter_thread)
+ priv->thr_callbacks.enter_thread (task, tself, priv->thr_user_data);
+
/* locking order is TASK_LOCK, LOCK */
g_static_rec_mutex_lock (lock);
GST_OBJECT_LOCK (task);
GST_OBJECT_UNLOCK (task);
g_static_rec_mutex_unlock (lock);
- /* now we allow messing with the lock again */
GST_OBJECT_LOCK (task);
- task->running = FALSE;
task->abidata.ABI.thread = NULL;
+
exit:
+ if (priv->thr_callbacks.leave_thread) {
+ /* fire the leave_thread callback when we need to. We need to do this before
+ * we signal the task and with the task lock released. */
+ GST_OBJECT_UNLOCK (task);
+ priv->thr_callbacks.leave_thread (task, tself, priv->thr_user_data);
+ GST_OBJECT_LOCK (task);
+ } else {
+ /* restore normal priority when releasing back into the pool, we will not
+ * touch the priority when a custom callback has been installed. */
+ g_thread_set_priority (tself, G_THREAD_PRIORITY_NORMAL);
+ }
+ /* now we allow messing with the lock again by setting the running flag to
+ * FALSE. Together with the SIGNAL this is the sign for the _join() to
+ * complete.
+ * Note that we still have not dropped the final ref on the task. We could
+ * check here if there is a pending join() going on and drop the last ref
+ * before releasing the lock as we can be sure that a ref is held by the
+ * caller of the join(). */
+ task->running = FALSE;
GST_TASK_SIGNAL (task);
GST_OBJECT_UNLOCK (task);
* gst_task_cleanup_all:
*
* Wait for all tasks to be stopped. This is mainly used internally
- * to ensure proper cleanup of internal datastructures in testsuites.
+ * to ensure proper cleanup of internal data structures in test suites.
*
* MT safe.
*/
GstTaskClass *klass;
if ((klass = g_type_class_peek (GST_TYPE_TASK))) {
- g_static_mutex_lock (&pool_lock);
- if (klass->pool) {
- /* Shut down all the threads, we still process the ones scheduled
- * because the unref happens in the thread function.
- * Also wait for currently running ones to finish. */
- g_thread_pool_free (klass->pool, FALSE, TRUE);
- /* create new pool, so we can still do something after this
- * call. */
- klass->pool = g_thread_pool_new (
- (GFunc) gst_task_func, klass, -1, FALSE, NULL);
- }
- g_static_mutex_unlock (&pool_lock);
+ init_klass_pool (klass);
}
}
* @func: The #GstTaskFunction to use
* @data: User data to pass to @func
*
- * Create a new Task that will repeadedly call the provided @func
+ * Create a new Task that will repeatedly call the provided @func
* with @data as a parameter. Typically the task will run in
* a new thread.
*
+ * The function cannot be changed after the task has been created. You
+ * must create a new #GstTask to change the function.
+ *
+ * This function will not yet create and start a thread. Use gst_task_start() or
+ * gst_task_pause() to create and start the GThread.
+ *
+ * Before the task can be used, a #GStaticRecMutex must be configured using the
+ * gst_task_set_lock() function. This lock will always be acquired while
+ * @func is called.
+ *
* Returns: A new #GstTask.
*
* MT safe.
{
GstTask *task;
- task = g_object_new (GST_TYPE_TASK, NULL);
+ task = g_object_newv (GST_TYPE_TASK, 0, NULL);
task->func = func;
task->data = data;
/**
* gst_task_set_lock:
* @task: The #GstTask to use
- * @mutex: The GMutex to use
+ * @mutex: The #GMutex to use
*
* Set the mutex used by the task. The mutex will be acquired before
* calling the #GstTaskFunction.
gst_task_set_lock (GstTask * task, GStaticRecMutex * mutex)
{
GST_OBJECT_LOCK (task);
- if (task->running)
+ if (G_UNLIKELY (task->running))
goto is_running;
GST_TASK_GET_LOCK (task) = mutex;
GST_OBJECT_UNLOCK (task);
}
}
+/**
+ * gst_task_set_priority:
+ * @task: a #GstTask
+ * @priority: a new priority for @task
+ *
+ * Changes the priority of @task to @priority.
+ *
+ * Note: try not to depend on task priorities.
+ *
+ * MT safe.
+ *
+ * Since: 0.10.24
+ */
+void
+gst_task_set_priority (GstTask * task, GThreadPriority priority)
+{
+ GstTaskPrivate *priv;
+ GThread *thread;
+
+ g_return_if_fail (GST_IS_TASK (task));
+
+ priv = task->priv;
+
+ GST_OBJECT_LOCK (task);
+ priv->prio_set = TRUE;
+ priv->priority = priority;
+ thread = task->abidata.ABI.thread;
+ if (thread != NULL) {
+ /* if this task already has a thread, we can configure the priority right
+ * away, else we do that when we assign a thread to the task. */
+ g_thread_set_priority (thread, priority);
+ }
+ GST_OBJECT_UNLOCK (task);
+}
+
+/**
+ * gst_task_get_pool:
+ * @task: a #GstTask
+ *
+ * Get the #GstTaskPool that this task will use for its streaming
+ * threads.
+ *
+ * MT safe.
+ *
+ * Returns: the #GstTaskPool used by @task. gst_object_unref()
+ * after usage.
+ *
+ * Since: 0.10.24
+ */
+GstTaskPool *
+gst_task_get_pool (GstTask * task)
+{
+ GstTaskPool *result;
+ GstTaskPrivate *priv;
+
+ g_return_val_if_fail (GST_IS_TASK (task), NULL);
+
+ priv = task->priv;
+
+ GST_OBJECT_LOCK (task);
+ result = gst_object_ref (priv->pool);
+ GST_OBJECT_UNLOCK (task);
+
+ return result;
+}
+
+/**
+ * gst_task_set_pool:
+ * @task: a #GstTask
+ * @pool: a #GstTaskPool
+ *
+ * Set @pool as the new GstTaskPool for @task. Any new streaming threads that
+ * will be created by @task will now use @pool.
+ *
+ * MT safe.
+ *
+ * Since: 0.10.24
+ */
+void
+gst_task_set_pool (GstTask * task, GstTaskPool * pool)
+{
+ GstTaskPool *old;
+ GstTaskPrivate *priv;
+
+ g_return_if_fail (GST_IS_TASK (task));
+ g_return_if_fail (GST_IS_TASK_POOL (pool));
+
+ priv = task->priv;
+
+ GST_OBJECT_LOCK (task);
+ if (priv->pool != pool) {
+ old = priv->pool;
+ priv->pool = gst_object_ref (pool);
+ } else
+ old = NULL;
+ GST_OBJECT_UNLOCK (task);
+
+ if (old)
+ gst_object_unref (old);
+}
+
+
+/**
+ * gst_task_set_thread_callbacks:
+ * @task: The #GstTask to use
+ * @callbacks: a #GstTaskThreadCallbacks pointer
+ * @user_data: user data passed to the callbacks
+ * @notify: called when @user_data is no longer referenced
+ *
+ * Set callbacks which will be executed when a new thread is needed, the thread
+ * function is entered and left and when the thread is joined.
+ *
+ * By default a thread for @task will be created from a default thread pool.
+ *
+ * Objects can use custom GThreads or can perform additional configuration of
+ * the threads (such as changing the thread priority) by installing callbacks.
+ *
+ * MT safe.
+ *
+ * Since: 0.10.24
+ */
+void
+gst_task_set_thread_callbacks (GstTask * task,
+ GstTaskThreadCallbacks * callbacks, gpointer user_data,
+ GDestroyNotify notify)
+{
+ GDestroyNotify old_notify;
+
+ g_return_if_fail (task != NULL);
+ g_return_if_fail (GST_IS_TASK (task));
+ g_return_if_fail (callbacks != NULL);
+
+ GST_OBJECT_LOCK (task);
+ old_notify = task->priv->thr_notify;
+
+ if (old_notify) {
+ gpointer old_data;
+
+ old_data = task->priv->thr_user_data;
+
+ task->priv->thr_user_data = NULL;
+ task->priv->thr_notify = NULL;
+ GST_OBJECT_UNLOCK (task);
+
+ old_notify (old_data);
+
+ GST_OBJECT_LOCK (task);
+ }
+ task->priv->thr_callbacks = *callbacks;
+ task->priv->thr_user_data = user_data;
+ task->priv->thr_notify = notify;
+ GST_OBJECT_UNLOCK (task);
+}
/**
* gst_task_get_state:
return result;
}
+/* make sure the task is running and start a thread if it's not.
+ * This function must be called with the task LOCK. */
+static gboolean
+start_task (GstTask * task)
+{
+ gboolean res = TRUE;
+ GError *error = NULL;
+ GstTaskPrivate *priv;
+
+ priv = task->priv;
+
+ /* new task, We ref before so that it remains alive while
+ * the thread is running. */
+ gst_object_ref (task);
+ /* mark task as running so that a join will wait until we schedule
+ * and exit the task function. */
+ task->running = TRUE;
+
+ /* push on the thread pool, we remember the original pool because the user
+ * could change it later on and then we join to the wrong pool. */
+ priv->pool_id = gst_object_ref (priv->pool);
+ priv->id =
+ gst_task_pool_push (priv->pool_id, (GstTaskPoolFunction) gst_task_func,
+ task, &error);
+
+ if (error != NULL) {
+ g_warning ("failed to create thread: %s", error->message);
+ g_error_free (error);
+ res = FALSE;
+ }
+ return res;
+}
+
+
/**
- * gst_task_start:
- * @task: The #GstTask to start
+ * gst_task_set_state:
+ * @task: a #GstTask
+ * @state: the new task state
*
- * Starts @task. The @task must have a lock associated with it using
- * gst_task_set_lock() or thsi function will return FALSE.
+ * Sets the state of @task to @state.
*
- * Returns: TRUE if the task could be started.
+ * The @task must have a lock associated with it using
+ * gst_task_set_lock() when going to GST_TASK_STARTED or GST_TASK_PAUSED or
+ * this function will return %FALSE.
*
* MT safe.
+ *
+ * Returns: %TRUE if the state could be changed.
+ *
+ * Since: 0.10.24
*/
gboolean
-gst_task_start (GstTask * task)
+gst_task_set_state (GstTask * task, GstTaskState state)
{
GstTaskState old;
+ gboolean res = TRUE;
g_return_val_if_fail (GST_IS_TASK (task), FALSE);
- GST_DEBUG_OBJECT (task, "Starting task %p", task);
+ GST_DEBUG_OBJECT (task, "Changing task %p to state %d", task, state);
GST_OBJECT_LOCK (task);
- if (G_UNLIKELY (GST_TASK_GET_LOCK (task) == NULL))
- goto no_lock;
+ if (state != GST_TASK_STOPPED)
+ if (G_UNLIKELY (GST_TASK_GET_LOCK (task) == NULL))
+ goto no_lock;
+ /* if the state changed, do our thing */
old = task->state;
- task->state = GST_TASK_STARTED;
- switch (old) {
- case GST_TASK_STOPPED:
- {
- GstTaskClass *tclass;
-
- tclass = GST_TASK_GET_CLASS (task);
-
- /* new task, push on threadpool. We ref before so
- * that it remains alive while on the threadpool. */
- gst_object_ref (task);
- g_static_mutex_lock (&pool_lock);
- g_thread_pool_push (tclass->pool, task, NULL);
- g_static_mutex_unlock (&pool_lock);
- break;
+ if (old != state) {
+ task->state = state;
+ switch (old) {
+ case GST_TASK_STOPPED:
+ /* If the task already has a thread scheduled we don't have to do
+ * anything. */
+ if (G_UNLIKELY (!task->running))
+ res = start_task (task);
+ break;
+ case GST_TASK_PAUSED:
+ /* when we are paused, signal to go to the new state */
+ GST_TASK_SIGNAL (task);
+ break;
+ case GST_TASK_STARTED:
+ /* if we were started, we'll go to the new state after the next
+ * iteration. */
+ break;
}
- case GST_TASK_PAUSED:
- /* PAUSE to PLAY, signal */
- GST_TASK_SIGNAL (task);
- break;
- case GST_TASK_STARTED:
- /* was OK */
- break;
}
GST_OBJECT_UNLOCK (task);
- return TRUE;
+ return res;
/* ERRORS */
no_lock:
{
- GST_WARNING_OBJECT (task, "starting task without a lock");
+ GST_WARNING_OBJECT (task, "state %d set on task without a lock", state);
GST_OBJECT_UNLOCK (task);
- g_warning ("starting task without a lock");
+ g_warning ("task without a lock can't be set to state %d", state);
return FALSE;
}
}
/**
+ * gst_task_start:
+ * @task: The #GstTask to start
+ *
+ * Starts @task. The @task must have a lock associated with it using
+ * gst_task_set_lock() or this function will return %FALSE.
+ *
+ * Returns: %TRUE if the task could be started.
+ *
+ * MT safe.
+ */
+gboolean
+gst_task_start (GstTask * task)
+{
+ return gst_task_set_state (task, GST_TASK_STARTED);
+}
+
+/**
* gst_task_stop:
* @task: The #GstTask to stop
*
* will not wait for the task to have completely stopped. Use
* gst_task_join() to stop and wait for completion.
*
- * Returns: TRUE if the task could be stopped.
+ * Returns: %TRUE if the task could be stopped.
*
* MT safe.
*/
gboolean
gst_task_stop (GstTask * task)
{
- GstTaskClass *tclass;
- GstTaskState old;
-
- g_return_val_if_fail (GST_IS_TASK (task), FALSE);
-
- tclass = GST_TASK_GET_CLASS (task);
-
- GST_DEBUG_OBJECT (task, "Stopping task %p", task);
-
- GST_OBJECT_LOCK (task);
- old = task->state;
- task->state = GST_TASK_STOPPED;
- switch (old) {
- case GST_TASK_STOPPED:
- break;
- case GST_TASK_PAUSED:
- GST_TASK_SIGNAL (task);
- break;
- case GST_TASK_STARTED:
- break;
- }
- GST_OBJECT_UNLOCK (task);
-
- return TRUE;
+ return gst_task_set_state (task, GST_TASK_STOPPED);
}
/**
* in the paused state. This function does not wait for the task to complete
* the paused state.
*
- * Returns: TRUE if the task could be paused.
+ * Returns: %TRUE if the task could be paused.
*
* MT safe.
*/
gboolean
gst_task_pause (GstTask * task)
{
- GstTaskState old;
-
- g_return_val_if_fail (GST_IS_TASK (task), FALSE);
-
- GST_DEBUG_OBJECT (task, "Pausing task %p", task);
-
- GST_OBJECT_LOCK (task);
- if (G_UNLIKELY (GST_TASK_GET_LOCK (task) == NULL))
- goto no_lock;
-
- old = task->state;
- task->state = GST_TASK_PAUSED;
- switch (old) {
- case GST_TASK_STOPPED:
- {
- GstTaskClass *tclass;
-
- tclass = GST_TASK_GET_CLASS (task);
-
- gst_object_ref (task);
- g_static_mutex_lock (&pool_lock);
- g_thread_pool_push (tclass->pool, task, NULL);
- g_static_mutex_unlock (&pool_lock);
- break;
- }
- case GST_TASK_PAUSED:
- break;
- case GST_TASK_STARTED:
- break;
- }
- GST_OBJECT_UNLOCK (task);
-
- return TRUE;
-
- /* ERRORS */
-no_lock:
- {
- GST_WARNING_OBJECT (task, "pausing task without a lock");
- GST_OBJECT_UNLOCK (task);
- g_warning ("pausing task without a lock");
- return FALSE;
- }
+ return gst_task_set_state (task, GST_TASK_PAUSED);
}
/**
* The task will automatically be stopped with this call.
*
* This function cannot be called from within a task function as this
- * will cause a deadlock.
+ * would cause a deadlock. The function will detect this and print a
+ * g_warning.
*
- * Returns: TRUE if the task could be joined.
+ * Returns: %TRUE if the task could be joined.
*
* MT safe.
*/
gst_task_join (GstTask * task)
{
GThread *tself;
+ GstTaskPrivate *priv;
+ gpointer id;
+ GstTaskPool *pool = NULL;
+
+ priv = task->priv;
g_return_val_if_fail (GST_IS_TASK (task), FALSE);
GST_DEBUG_OBJECT (task, "Joining task %p, thread %p", task, tself);
+ /* we don't use a real thread join here because we are using
+ * thread pools */
GST_OBJECT_LOCK (task);
- if (tself == task->abidata.ABI.thread)
+ if (G_UNLIKELY (tself == task->abidata.ABI.thread))
goto joining_self;
task->state = GST_TASK_STOPPED;
+ /* signal the state change for when it was blocked in PAUSED. */
GST_TASK_SIGNAL (task);
- while (task->running)
+ /* we set the running flag when pushing the task on the thread pool.
+ * This means that the task function might not be called when we try
+ * to join it here. */
+ while (G_LIKELY (task->running))
GST_TASK_WAIT (task);
+ /* clean the thread */
+ task->abidata.ABI.thread = NULL;
+ /* get the id and pool to join */
+ pool = priv->pool_id;
+ id = priv->id;
+ priv->pool_id = NULL;
+ priv->id = NULL;
GST_OBJECT_UNLOCK (task);
+ if (pool) {
+ if (id)
+ gst_task_pool_join (pool, id);
+ gst_object_unref (pool);
+ }
+
GST_DEBUG_OBJECT (task, "Joined task %p", task);
return TRUE;
{
GST_WARNING_OBJECT (task, "trying to join task from its thread");
GST_OBJECT_UNLOCK (task);
- g_warning ("trying to join task %p from its thread would deadlock", task);
+ g_warning ("\nTrying to join task %p from its thread would deadlock.\n"
+ "You cannot change the state of an element from its streaming\n"
+ "thread. Use g_idle_add() or post a GstMessage on the bus to\n"
+ "schedule the state change from the main thread.\n", task);
return FALSE;
}
}