GstTask

typedef struct {
  GstTaskState     state;
  GCond 	  *cond;

  GStaticRecMutex *lock;

  GstTaskFunction  func;
  gpointer 	   data;

  gboolean	   running;
} GstTask;

The GstTask object.

GstTaskFunction ()

void                (*GstTaskFunction)                  (void *data);

A function that will repeatedly be called in the thread created by a GstTask.

enum GstTaskState

typedef enum {
  GST_TASK_STARTED,
  GST_TASK_STOPPED,
  GST_TASK_PAUSED
} GstTaskState;

The different states a task can be in

GST_TASK_BROADCAST()

#define GST_TASK_BROADCAST(task)	g_cond_breadcast(GST_TASK_GET_COND (task))

Send a broadcast signal to all waiting task conds

GST_TASK_GET_COND()

#define GST_TASK_GET_COND(task)		(GST_TASK_CAST(task)->cond)

Get access to the cond of the task.

GST_TASK_GET_LOCK()

#define GST_TASK_GET_LOCK(task)		(GST_TASK_CAST(task)->lock)

Get access to the task lock.

GST_TASK_SIGNAL()

#define GST_TASK_SIGNAL(task)		g_cond_signal(GST_TASK_GET_COND (task))

Signal the task cond

GST_TASK_STATE()

#define GST_TASK_STATE(task)		(GST_TASK_CAST(task)->state)

Get access to the state of the task.

GST_TASK_WAIT()

#define GST_TASK_WAIT(task)		g_cond_wait(GST_TASK_GET_COND (task), GST_OBJECT_GET_LOCK (task))

Wait for the task cond to be signalled

gst_task_create ()

GstTask*            gst_task_create                     (GstTaskFunction func,
                                                         gpointer data);

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.

gst_task_set_lock ()

void                gst_task_set_lock                   (GstTask *task,
                                                         GStaticRecMutex *mutex);

Set the mutex used by the task. The mutex will be acquired before calling the GstTaskFunction.

This function has to be called before calling gst_task_pause() or gst_task_start().

MT safe.

gst_task_set_priority ()

void                gst_task_set_priority               (GstTask *task,
                                                         GThreadPriority priority);

Changes the priority of task to priority.

Note: try not to depend on task priorities.

MT safe.

Since 0.10.24

gst_task_set_pool ()

void                gst_task_set_pool                   (GstTask *task,
                                                         GstTaskPool *pool);

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

gst_task_get_pool ()

GstTaskPool*        gst_task_get_pool                   (GstTask *task);

Get the GstTaskPool that this task will use for its streaming threads.

MT safe.

Since 0.10.24

GstTaskThreadCallbacks

typedef struct {
  /* manage the lifetime of the thread */
  void      (*enter_thread)     (GstTask *task, GThread *thread, gpointer user_data);
  void      (*leave_thread)     (GstTask *task, GThread *thread, gpointer user_data);
} GstTaskThreadCallbacks;

Custom GstTask thread callback functions that can be installed.

Since 0.10.24

gst_task_set_thread_callbacks ()

void                gst_task_set_thread_callbacks       (GstTask *task,
                                                         GstTaskThreadCallbacks *callbacks,
                                                         gpointer user_data,
                                                         GDestroyNotify notify);

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

gst_task_get_state ()

GstTaskState        gst_task_get_state                  (GstTask *task);

Get the current state of the task.

gst_task_set_state ()

gboolean            gst_task_set_state                  (GstTask *task,
                                                         GstTaskState state);

Sets the state of task to state.

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.

Since 0.10.24

gst_task_pause ()

gboolean            gst_task_pause                      (GstTask *task);

Pauses task. This method can also be called on a task in the stopped state, in which case a thread will be started and will remain in the paused state. This function does not wait for the task to complete the paused state.

gst_task_start ()

gboolean            gst_task_start                      (GstTask *task);

Starts task. The task must have a lock associated with it using gst_task_set_lock() or this function will return FALSE.

gst_task_stop ()

gboolean            gst_task_stop                       (GstTask *task);

Stops task. This method merely schedules the task to stop and will not wait for the task to have completely stopped. Use gst_task_join() to stop and wait for completion.

gst_task_join ()

gboolean            gst_task_join                       (GstTask *task);

Joins task. After this call, it is safe to unref the task and clean up the lock set with gst_task_set_lock().

The task will automatically be stopped with this call.

This function cannot be called from within a task function as this would cause a deadlock. The function will detect this and print a g_warning.

gst_task_cleanup_all ()

void                gst_task_cleanup_all                (void);

Wait for all tasks to be stopped. This is mainly used internally to ensure proper cleanup of internal data structures in test suites.

MT safe.