GstMiniObjectCopyFunction ()

GstMiniObject *
(*GstMiniObjectCopyFunction) (const GstMiniObject *obj);

Function prototype for methods to create copies of instances.

GstMiniObjectDisposeFunction ()

gboolean
(*GstMiniObjectDisposeFunction) (GstMiniObject *obj);

Function prototype for when a miniobject has lost its last refcount. Implementation of the mini object are allowed to revive the passed object by doing a gst_mini_object_ref(). If the object is not revived after the dispose function, the function should return TRUE and the memory associated with the object is freed.

GstMiniObjectFreeFunction ()

void
(*GstMiniObjectFreeFunction) (GstMiniObject *obj);

Virtual function prototype for methods to free resources used by mini-objects.

GstMiniObjectNotify ()

void
(*GstMiniObjectNotify) (gpointer user_data,
                        GstMiniObject *obj);

A GstMiniObjectNotify function can be added to a mini object as a callback that gets triggered when gst_mini_object_unref() drops the last ref and obj is about to be freed.

GST_MINI_OBJECT_TYPE()

#define GST_MINI_OBJECT_TYPE(obj)  (GST_MINI_OBJECT_CAST(obj)->type)

This macro returns the type of the mini-object.

GST_MINI_OBJECT_FLAGS()

#define GST_MINI_OBJECT_FLAGS(obj)  (GST_MINI_OBJECT_CAST(obj)->flags)

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

GST_MINI_OBJECT_FLAG_IS_SET()

#define GST_MINI_OBJECT_FLAG_IS_SET(obj,flag)        !!(GST_MINI_OBJECT_FLAGS (obj) & (flag))

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

GST_MINI_OBJECT_FLAG_SET()

#define GST_MINI_OBJECT_FLAG_SET(obj,flag)           (GST_MINI_OBJECT_FLAGS (obj) |= (flag))

This macro sets the given bits.

GST_MINI_OBJECT_FLAG_UNSET()

#define GST_MINI_OBJECT_FLAG_UNSET(obj,flag)         (GST_MINI_OBJECT_FLAGS (obj) &= ~(flag))

This macro unsets the given bits.

GST_MINI_OBJECT_IS_LOCKABLE()

#define GST_MINI_OBJECT_IS_LOCKABLE(obj)  GST_MINI_OBJECT_FLAG_IS_SET(obj, GST_MINI_OBJECT_FLAG_LOCKABLE)

Check if obj is lockable. A lockable object can be locked and unlocked with gst_mini_object_lock() and gst_mini_object_unlock().

GST_MINI_OBJECT_REFCOUNT()

#define GST_MINI_OBJECT_REFCOUNT(obj)           ((GST_MINI_OBJECT_CAST(obj))->refcount)

Get access to the reference count field of the mini-object.

GST_MINI_OBJECT_REFCOUNT_VALUE()

#define GST_MINI_OBJECT_REFCOUNT_VALUE(obj)     (g_atomic_int_get (&(GST_MINI_OBJECT_CAST(obj))->refcount))

Get the reference count value of the mini-object.

GST_DEFINE_MINI_OBJECT_TYPE()

#define             GST_DEFINE_MINI_OBJECT_TYPE(TypeName,type_name)

Define a new mini-object type with the given name

gst_mini_object_init ()

void
gst_mini_object_init (GstMiniObject *mini_object,
                      guint flags,
                      GType type,
                      GstMiniObjectCopyFunction copy_func,
                      GstMiniObjectDisposeFunction dispose_func,
                      GstMiniObjectFreeFunction free_func);

Initializes a mini-object with the desired type and copy/dispose/free functions.

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gst_mini_object_ref ()

GstMiniObject *
gst_mini_object_ref (GstMiniObject *mini_object);

Increase the reference count of the mini-object.

Note that the refcount affects the writability of mini -object, see gst_mini_object_is_writable(). It is important to note that keeping additional references to GstMiniObject instances can potentially increase the number of memcpy operations in a pipeline, especially if the miniobject is a GstBuffer.

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gst_mini_object_unref ()

void
gst_mini_object_unref (GstMiniObject *mini_object);

Decreases the reference count of the mini-object, possibly freeing the mini-object.

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gst_mini_object_weak_ref ()

void
gst_mini_object_weak_ref (GstMiniObject *object,
                          GstMiniObjectNotify notify,
                          gpointer data);

Adds a weak reference callback to a mini object. Weak references are used for notification when a mini object is finalized. They are called "weak references" because they allow you to safely hold a pointer to the mini object without calling gst_mini_object_ref() (gst_mini_object_ref() adds a strong reference, that is, forces the object to stay alive).

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gst_mini_object_weak_unref ()

void
gst_mini_object_weak_unref (GstMiniObject *object,
                            GstMiniObjectNotify notify,
                            gpointer data);

Removes a weak reference callback from a mini object.

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gst_mini_object_lock ()

gboolean
gst_mini_object_lock (GstMiniObject *object,
                      GstLockFlags flags);

Lock the mini-object with the specified access mode in flags .

gst_mini_object_unlock ()

void
gst_mini_object_unlock (GstMiniObject *object,
                        GstLockFlags flags);

Unlock the mini-object with the specified access mode in flags .

gst_mini_object_is_writable ()

gboolean
gst_mini_object_is_writable (const GstMiniObject *mini_object);

If mini_object has the LOCKABLE flag set, check if the current EXCLUSIVE lock on object is the only one, this means that changes to the object will not be visible to any other object.

If the LOCKABLE flag is not set, check if the refcount of mini_object is exactly 1, meaning that no other reference exists to the object and that the object is therefore writable.

Modification of a mini-object should only be done after verifying that it is writable.

gst_mini_object_make_writable ()

GstMiniObject *
gst_mini_object_make_writable (GstMiniObject *mini_object);

Checks if a mini-object is writable. If not, a writable copy is made and returned. This gives away the reference to the original mini object, and returns a reference to the new object.

MT safe

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gst_mini_object_copy ()

GstMiniObject *
gst_mini_object_copy (const GstMiniObject *mini_object);

Creates a copy of the mini-object.

MT safe

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gst_mini_object_set_qdata ()

void
gst_mini_object_set_qdata (GstMiniObject *object,
                           GQuark quark,
                           gpointer data,
                           GDestroyNotify destroy);

This sets an opaque, named pointer on a miniobject. The name is specified through a GQuark (retrieved e.g. via g_quark_from_static_string()), and the pointer can be gotten back from the object with gst_mini_object_get_qdata() until the object is disposed. Setting a previously set user data pointer, overrides (frees) the old pointer set, using NULL as pointer essentially removes the data stored.

destroy may be specified which is called with data as argument when the object is disposed, or the data is being overwritten by a call to gst_mini_object_set_qdata() with the same quark .

gst_mini_object_get_qdata ()

gpointer
gst_mini_object_get_qdata (GstMiniObject *object,
                           GQuark quark);

This function gets back user data pointers stored via gst_mini_object_set_qdata().

gst_mini_object_steal_qdata ()

gpointer
gst_mini_object_steal_qdata (GstMiniObject *object,
                             GQuark quark);

This function gets back user data pointers stored via gst_mini_object_set_qdata() and removes the data from object without invoking its destroy() function (if any was set).

gst_mini_object_replace ()

gboolean
gst_mini_object_replace (GstMiniObject **olddata,
                         GstMiniObject *newdata);

Atomically modifies a pointer to point to a new mini-object. The reference count of olddata is decreased and the reference count of newdata is increased.

Either newdata and the value pointed to by olddata may be NULL.

gst_mini_object_take ()

gboolean
gst_mini_object_take (GstMiniObject **olddata,
                      GstMiniObject *newdata);

Modifies a pointer to point to a new mini-object. The modification is done atomically. This version is similar to gst_mini_object_replace() except that it does not increase the refcount of newdata and thus takes ownership of newdata .

Either newdata and the value pointed to by olddata may be NULL.

gst_mini_object_steal ()

GstMiniObject *
gst_mini_object_steal (GstMiniObject **olddata);

Replace the current GstMiniObject pointer to by olddata with NULL and return the old value.

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struct GstMiniObject

struct GstMiniObject {
  GType   type;

  gint    refcount;
  gint    lockstate;
  guint   flags;

  GstMiniObjectCopyFunction copy;
  GstMiniObjectDisposeFunction dispose;
  GstMiniObjectFreeFunction free;
};

Base class for refcounted lightweight objects.

enum GstMiniObjectFlags

Flags for the mini object

enum GstLockFlags

Flags used when locking miniobjects

GST_LOCK_FLAG_READWRITE

#define GST_LOCK_FLAG_READWRITE  (GST_LOCK_FLAG_READ | GST_LOCK_FLAG_WRITE)

GstLockFlags value alias for GST_LOCK_FLAG_READ | GST_LOCK_FLAG_WRITE