GstObject

typedef struct {
  gint           refcount;

  GMutex        *lock;        /* object LOCK */
  gchar         *name;        /* object name */
  gchar         *name_prefix; /* used for debugging */
  GstObject     *parent;      /* this object's parent, weak ref */
  guint32        flags;
} GstObject;

GStreamer base object class.

enum GstObjectFlags

typedef enum
{
  GST_OBJECT_DISPOSING = (1<<0),
  GST_OBJECT_FLOATING = (1<<1),
  /* padding */
  GST_OBJECT_FLAG_LAST = (1<<4)
} GstObjectFlags;

The standard flags that an gstobject may have.

GST_OBJECT_FLAGS()

#define GST_OBJECT_FLAGS(obj)                  (GST_OBJECT_CAST (obj)->flags)

This macro returns the entire set of flags for the object.

GST_OBJECT_FLAG_IS_SET()

#define GST_OBJECT_FLAG_IS_SET(obj,flag)       ((GST_OBJECT_FLAGS (obj) & (flag)) == (flag))

This macro checks to see if the given flag is set.

GST_OBJECT_FLAG_SET()

#define GST_OBJECT_FLAG_SET(obj,flag)          (GST_OBJECT_FLAGS (obj) |= (flag))

This macro sets the given bits.

GST_OBJECT_FLAG_UNSET()

#define GST_OBJECT_FLAG_UNSET(obj,flag)        (GST_OBJECT_FLAGS (obj) &= ~(flag))

This macro usets the given bits.

GST_OBJECT_NAME()

#define GST_OBJECT_NAME(obj)            (GST_OBJECT_CAST(obj)->name)

Get the name of this object

GST_OBJECT_PARENT()

#define GST_OBJECT_PARENT(obj)          (GST_OBJECT_CAST(obj)->parent)

Get the parent of this object

GST_OBJECT_IS_DISPOSING()

#define GST_OBJECT_IS_DISPOSING(obj)    (GST_OBJECT_FLAG_IS_SET (obj, GST_OBJECT_DISPOSING))

Check if the given object is beeing destroyed.

GST_OBJECT_IS_FLOATING()

#define GST_OBJECT_IS_FLOATING(obj)     (GST_OBJECT_FLAG_IS_SET (obj, GST_OBJECT_FLOATING))

Check if the given object is floating (has no owner).

GST_OBJECT_REFCOUNT()

#define GST_OBJECT_REFCOUNT(obj)                (((GObject*)(obj))->ref_count)

Get access to the reference count field of the object.

GST_OBJECT_REFCOUNT_VALUE()

#define GST_OBJECT_REFCOUNT_VALUE(obj)          g_atomic_int_get ((gint *) &GST_OBJECT_REFCOUNT(obj))

Get the reference count value of the object.

GST_CLASS_GET_LOCK()

#define GST_CLASS_GET_LOCK(obj)         (GST_OBJECT_CLASS_CAST(obj)->lock)

This macro will return the class lock used to protect deep_notify signal emission on thread-unsafe glib versions (glib < 2.8).

GST_CLASS_LOCK()

#define GST_CLASS_LOCK(obj)             (g_static_rec_mutex_lock(GST_CLASS_GET_LOCK(obj)))

Lock the class.

GST_CLASS_TRYLOCK()

#define GST_CLASS_TRYLOCK(obj)          (g_static_rec_mutex_trylock(GST_CLASS_GET_LOCK(obj)))

Try to lock the class, returns TRUE if class could be locked.

GST_CLASS_UNLOCK()

#define GST_CLASS_UNLOCK(obj)           (g_static_rec_mutex_unlock(GST_CLASS_GET_LOCK(obj)))

Unlock the class.

GST_OBJECT_LOCK()

#define GST_OBJECT_LOCK(obj)                   g_mutex_lock(GST_OBJECT_GET_LOCK(obj))

This macro will obtain a lock on the object, making serialization possible. It blocks until the lock can be obtained.

GST_OBJECT_TRYLOCK()

#define GST_OBJECT_TRYLOCK(obj)                g_mutex_trylock(GST_OBJECT_GET_LOCK(obj))

This macro will try to obtain a lock on the object, but will return with FALSE if it can't get it immediately.

GST_OBJECT_UNLOCK()

#define GST_OBJECT_UNLOCK(obj)                 g_mutex_unlock(GST_OBJECT_GET_LOCK(obj))

This macro releases a lock on the object.

GST_OBJECT_GET_LOCK()

#define GST_OBJECT_GET_LOCK(obj)               (GST_OBJECT_CAST(obj)->lock)

Acquire a reference to the mutex of this object.

gst_object_set_name ()

gboolean            gst_object_set_name                 (GstObject *object,
                                                         const gchar *name);

Sets the name of object, or gives object a guaranteed unique name (if name is NULL). This function makes a copy of the provided name, so the caller retains ownership of the name it sent.

gst_object_get_name ()

gchar*              gst_object_get_name                 (GstObject *object);

Returns a copy of the name of object. Caller should g_free() the return value after usage. For a nameless object, this returns NULL, which you can safely g_free() as well.

gst_object_set_parent ()

gboolean            gst_object_set_parent               (GstObject *object,
                                                         GstObject *parent);

Sets the parent of object to parent. The object's reference count will be incremented, and any floating reference will be removed (see gst_object_sink()).

This function causes the parent-set signal to be emitted when the parent was successfully set.

gst_object_get_parent ()

GstObject*          gst_object_get_parent               (GstObject *object);

Returns the parent of object. This function increases the refcount of the parent object so you should gst_object_unref() it after usage.

gst_object_unparent ()

void                gst_object_unparent                 (GstObject *object);

Clear the parent of object, removing the associated reference. This function decreases the refcount of object.

MT safe. Grabs and releases object's lock.

gst_object_get_name_prefix ()

gchar*              gst_object_get_name_prefix          (GstObject *object);

Returns a copy of the name prefix of object. Caller should g_free() the return value after usage. For a prefixless object, this returns NULL, which you can safely g_free() as well.

gst_object_set_name_prefix ()

void                gst_object_set_name_prefix          (GstObject *object,
                                                         const gchar *name_prefix);

Sets the name prefix of object to name_prefix. This function makes a copy of the provided name prefix, so the caller retains ownership of the name prefix it sent.

MT safe. This function grabs and releases object's LOCK.

gst_object_default_deep_notify ()

void                gst_object_default_deep_notify      (GObject *object,
                                                         GstObject *orig,
                                                         GParamSpec *pspec,
                                                         gchar **excluded_props);

A default deep_notify signal callback for an object. The user data should contain a pointer to an array of strings that should be excluded from the notify. The default handler will print the new value of the property using g_print.

MT safe. This function grabs and releases object's LOCK for getting its path string.

gst_object_default_error ()

void                gst_object_default_error            (GstObject *source,
                                                         GError *error,
                                                         gchar *debug);

A default error function.

The default handler will simply print the error string using g_print.

gst_object_check_uniqueness ()

gboolean            gst_object_check_uniqueness         (GList *list,
                                                         const gchar *name);

Checks to see if there is any object named name in list. This function does not do any locking of any kind. You might want to protect the provided list with the lock of the owner of the list. This function will lock each GstObject in the list to compare the name, so be carefull when passing a list with a locked object.

gst_object_has_ancestor ()

gboolean            gst_object_has_ancestor             (GstObject *object,
                                                         GstObject *ancestor);

Check if object has an ancestor ancestor somewhere up in the hierarchy.

gst_object_save_thyself ()

GstXmlNodePtr       gst_object_save_thyself             (GstObject *object,
                                                         GstXmlNodePtr parent);

Saves object into the parent XML node.

gst_object_restore_thyself ()

void                gst_object_restore_thyself          (GstObject *object,
                                                         GstXmlNodePtr self);

Restores object with the data from the parent XML node.

gst_object_ref ()

gpointer            gst_object_ref                      (gpointer object);

Increments the reference count on object. This function does not take the lock on object because it relies on atomic refcounting.

This object returns the input parameter to ease writing constructs like : result = gst_object_ref (object->parent);

gst_object_unref ()

void                gst_object_unref                    (gpointer object);

Decrements the reference count on object. If reference count hits zero, destroy object. This function does not take the lock on object as it relies on atomic refcounting.

The unref method should never be called with the LOCK held since this might deadlock the dispose function.

gst_object_sink ()

void                gst_object_sink                     (gpointer object);

If object was floating, the GST_OBJECT_FLOATING flag is removed and object is unreffed. When object was not floating, this function does nothing.

Any newly created object has a refcount of 1 and is floating. This function should be used when creating a new object to symbolically 'take ownership' of object. This done by first doing a gst_object_ref() to keep a reference to object and then gst_object_sink() to remove and unref any floating references to object. Use gst_object_set_parent() to have this done for you.

MT safe. This function grabs and releases object lock.

gst_object_replace ()

void                gst_object_replace                  (GstObject **oldobj,
                                                         GstObject *newobj);

Unrefs the GstObject pointed to by oldobj, refs newobj and puts newobj in *oldobj. Be carefull when calling this function, it does not take any locks. You might want to lock the object owning oldobj pointer before calling this function.

Make sure not to LOCK oldobj because it might be unreffed which could cause a deadlock when it is disposed.

gst_object_get_path_string ()

gchar*              gst_object_get_path_string          (GstObject *object);

Generates a string describing the path of object in the object hierarchy. Only useful (or used) for debugging.

gst_class_signal_connect ()

guint               gst_class_signal_connect            (GstObjectClass *klass,
                                                         const gchar *name,
                                                         gpointer func,
                                                         gpointer func_data);

Connect to a class signal.

gst_class_signal_emit_by_name ()

void                gst_class_signal_emit_by_name       (GstObject *object,
                                                         const gchar *name,
                                                         GstXmlNodePtr self);

emits the named class signal.

The "name" property

  "name"                     gchar*                : Read / Write / Construct

The name of the object.

Default value: NULL

The "deep-notify" signal

void                user_function                      (GstObject  *gstobject,
                                                        GstObject  *prop_object,
                                                        GParamSpec *prop,
                                                        gpointer    user_data)        : Run First / No Recursion / Has Details / No Hooks

The deep notify signal is used to be notified of property changes. It is typically attached to the toplevel bin to receive notifications from all the elements contained in that bin.

The "object-saved" signal

void                user_function                      (GstObject *gstobject,
                                                        gpointer   xml_node,
                                                        gpointer   user_data)      : Run Last

Trigered whenever a new object is saved to XML. You can connect to this signal to insert custom XML tags into the core XML.

The "parent-set" signal

void                user_function                      (GstObject *gstobject,
                                                        GstObject *parent,
                                                        gpointer   user_data)      : Run Last

Emitted when the parent of an object is set.

The "parent-unset" signal

void                user_function                      (GstObject *gstobject,
                                                        GstObject *parent,
                                                        gpointer   user_data)      : Run Last

Emitted when the parent of an object is unset.