* SECTION:gstminiobject
* @short_description: Lightweight base class for the GStreamer object hierarchy
*
- * #GstMiniObject is a baseclass like #GObject, but has been stripped down of
- * features to be fast and small.
- * It offers sub-classing and ref-counting in the same way as #GObject does.
- * It has no properties and no signal-support though.
+ * #GstMiniObject is a simple structure that can be used to implement refcounted
+ * types.
*
- * Last reviewed on 2005-11-23 (0.9.5)
+ * Subclasses will include #GstMiniObject as the first member in their structure
+ * and then call gst_mini_object_init() to initialize the #GstMiniObject fields.
+ *
+ * gst_mini_object_ref() and gst_mini_object_unref() increment and decrement the
+ * refcount respectively. When the refcount of a mini-object reaches 0, the
+ * dispose function is called first and when this returns %TRUE, the free
+ * function of the miniobject is called.
+ *
+ * A copy can be made with gst_mini_object_copy().
+ *
+ * gst_mini_object_is_writable() will return %TRUE when the refcount of the
+ * object is exactly 1, meaning the current caller has the only reference to the
+ * object. gst_mini_object_make_writable() will return a writable version of the
+ * object, which might be a new copy when the refcount was not 1.
+ *
+ * Opaque data can be associated with a #GstMiniObject with
+ * gst_mini_object_set_qdata() and gst_mini_object_get_qdata(). The data is
+ * meant to be specific to the particular object and is not automatically copied
+ * with gst_mini_object_copy() or similar methods.
+ *
+ * A weak reference can be added and remove with gst_mini_object_weak_ref()
+ * and gst_mini_object_weak_unref() respectively.
+ *
+ * Last reviewed on 2012-06-15 (0.11.93)
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
/* Mutex used for weak referencing */
-G_LOCK_DEFINE_STATIC (weak_refs_mutex);
+G_LOCK_DEFINE_STATIC (qdata_mutex);
+static GQuark weak_ref_quark;
+
+typedef struct
+{
+ GQuark quark;
+ GstMiniObjectWeakNotify notify;
+ gpointer data;
+} GstQData;
+
+#define QDATA(o,i) ((GstQData *)(o)->qdata)[(i)]
+#define QDATA_QUARK(o,i) (QDATA(o,i).quark)
+#define QDATA_NOTIFY(o,i) (QDATA(o,i).notify)
+#define QDATA_DATA(o,i) (QDATA(o,i).data)
void
_priv_gst_mini_object_initialize (void)
{
+ weak_ref_quark = g_quark_from_static_string ("GstMiniObjectWeakRefQuark");
+
#ifndef GST_DISABLE_TRACE
_gst_mini_object_trace = _gst_alloc_trace_register ("GstMiniObject", 0);
#endif
}
/**
- * gst_mini_object_init:
+ * gst_mini_object_init: (skip)
* @mini_object: a #GstMiniObject
* @type: the #GType of the mini-object to create
- * @size: the size of the data
+ * @copy_func: the copy function, or NULL
+ * @dispose_func: the dispose function, or NULL
+ * @free_func: the free function or NULL
*
- * Initializes a mini-object with the desired type and size.
+ * Initializes a mini-object with the desired type and copy/dispose/free
+ * functions.
*
* MT safe
*
* Returns: (transfer full): the new mini-object.
*/
void
-gst_mini_object_init (GstMiniObject * mini_object, GType type, gsize size)
+gst_mini_object_init (GstMiniObject * mini_object, GType type,
+ GstMiniObjectCopyFunction copy_func,
+ GstMiniObjectDisposeFunction dispose_func,
+ GstMiniObjectFreeFunction free_func)
{
mini_object->type = type;
mini_object->refcount = 1;
mini_object->flags = 0;
- mini_object->size = size;
- mini_object->n_weak_refs = 0;
- mini_object->weak_refs = NULL;
+
+ mini_object->copy = copy_func;
+ mini_object->dispose = dispose_func;
+ mini_object->free = free_func;
+
+ mini_object->n_qdata = 0;
+ mini_object->qdata = NULL;
#ifndef GST_DISABLE_TRACE
_gst_alloc_trace_new (_gst_mini_object_trace, mini_object);
* @mini_object: the mini-object to check
*
* Checks if a mini-object is writable. A mini-object is writable
- * if the reference count is one and the #GST_MINI_OBJECT_FLAG_READONLY
- * flag is not set. Modification of a mini-object should only be
- * done after verifying that it is writable.
+ * if the reference count is one. Modification of a mini-object should
+ * only be done after verifying that it is writable.
*
* MT safe
*
}
static void
-weak_refs_notify (GstMiniObject * obj)
+qdata_notify (GstMiniObject * obj)
{
guint i;
- for (i = 0; i < obj->n_weak_refs; i++)
- obj->weak_refs[i].notify (obj->weak_refs[i].data, obj);
- g_free (obj->weak_refs);
+ for (i = 0; i < obj->n_qdata; i++)
+ QDATA_NOTIFY (obj, i) (QDATA_DATA (obj, i), obj);
+ g_free (obj->qdata);
}
/**
* want to free the instance anymore */
if (G_LIKELY (do_free)) {
/* The weak reference stack is freed in the notification function */
- if (mini_object->n_weak_refs)
- weak_refs_notify (mini_object);
+ if (mini_object->n_qdata)
+ qdata_notify (mini_object);
#ifndef GST_DISABLE_TRACE
_gst_alloc_trace_free (_gst_mini_object_trace, mini_object);
g_return_if_fail (notify != NULL);
g_return_if_fail (GST_MINI_OBJECT_REFCOUNT_VALUE (object) >= 1);
- G_LOCK (weak_refs_mutex);
-
- if (object->n_weak_refs) {
- /* Don't add the weak reference if it already exists. */
- for (i = 0; i < object->n_weak_refs; i++) {
- if (object->weak_refs[i].notify == notify &&
- object->weak_refs[i].data == data) {
- g_warning ("%s: Attempt to re-add existing weak ref %p(%p) failed.",
- G_STRFUNC, notify, data);
- goto found;
- }
- }
-
- i = object->n_weak_refs++;
- object->weak_refs =
- g_realloc (object->weak_refs, sizeof (object->weak_refs[0]) * i);
- } else {
- object->weak_refs = g_malloc0 (sizeof (object->weak_refs[0]));
- object->n_weak_refs = 1;
- i = 0;
- }
- object->weak_refs[i].notify = notify;
- object->weak_refs[i].data = data;
-found:
- G_UNLOCK (weak_refs_mutex);
+ G_LOCK (qdata_mutex);
+ i = object->n_qdata++;
+ object->qdata =
+ g_realloc (object->qdata, sizeof (GstQData) * object->n_qdata);
+ QDATA_QUARK (object, i) = weak_ref_quark;
+ QDATA_NOTIFY (object, i) = notify;
+ QDATA_DATA (object, i) = data;
+ G_UNLOCK (qdata_mutex);
}
/**
gst_mini_object_weak_unref (GstMiniObject * object,
GstMiniObjectWeakNotify notify, gpointer data)
{
+ guint i;
gboolean found_one = FALSE;
g_return_if_fail (object != NULL);
g_return_if_fail (notify != NULL);
- G_LOCK (weak_refs_mutex);
+ G_LOCK (qdata_mutex);
+ for (i = 0; i < object->n_qdata; i++) {
+ if (QDATA_QUARK (object, i) == weak_ref_quark &&
+ QDATA_NOTIFY (object, i) == notify && QDATA_DATA (object, i) == data) {
+ found_one = TRUE;
+ if (--object->n_qdata == 0) {
+ /* we don't shrink but free when everything is gone */
+ g_free (object->qdata);
+ object->qdata = NULL;
+ } else if (i != object->n_qdata)
+ QDATA (object, i) = QDATA (object, object->n_qdata);
+ break;
+ }
+ }
+ G_UNLOCK (qdata_mutex);
- if (object->n_weak_refs) {
- guint i;
+ if (!found_one)
+ g_warning ("%s: couldn't find weak ref %p(%p)", G_STRFUNC, notify, data);
+}
- for (i = 0; i < object->n_weak_refs; i++)
- if (object->weak_refs[i].notify == notify &&
- object->weak_refs[i].data == data) {
- found_one = TRUE;
- object->n_weak_refs -= 1;
- if (i != object->n_weak_refs)
- object->weak_refs[i] = object->weak_refs[object->n_weak_refs];
+/**
+ * gst_mini_object_set_qdata:
+ * @object: a #GstMiniObject
+ * @quark: A #GQuark, naming the user data pointer
+ * @data: An opaque user data pointer
+ * @destroy: Function to invoke with @data as argument, when @data
+ * needs to be freed
+ *
+ * This sets an opaque, named pointer on a miniobject.
+ * The name is specified through a #GQuark (retrived 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.
+ */
+void
+gst_mini_object_set_qdata (GstMiniObject * object, GQuark quark,
+ gpointer data, GDestroyNotify destroy)
+{
+ guint i;
+ gpointer old_data = NULL;
+ GDestroyNotify old_notify = NULL;
- break;
+ g_return_if_fail (object != NULL);
+ g_return_if_fail (quark > 0);
+
+ G_LOCK (qdata_mutex);
+ for (i = 0; i < object->n_qdata; i++) {
+ if (QDATA_QUARK (object, i) == quark) {
+ old_data = QDATA_DATA (object, i);
+ old_notify = (GDestroyNotify) QDATA_NOTIFY (object, i);
+
+ if (data == NULL) {
+ /* remove item */
+ if (--object->n_qdata == 0) {
+ /* we don't shrink but free when everything is gone */
+ g_free (object->qdata);
+ object->qdata = NULL;
+ } else if (i != object->n_qdata)
+ QDATA (object, i) = QDATA (object, object->n_qdata);
}
+ break;
+ }
}
- G_UNLOCK (weak_refs_mutex);
- if (!found_one)
- g_warning ("%s: couldn't find weak ref %p(%p)", G_STRFUNC, notify, data);
+ if (!old_data) {
+ /* add item */
+ i = object->n_qdata++;
+ object->qdata =
+ g_realloc (object->qdata, sizeof (GstQData) * object->n_qdata);
+ }
+ QDATA_QUARK (object, i) = quark;
+ QDATA_DATA (object, i) = data;
+ QDATA_NOTIFY (object, i) = (GstMiniObjectWeakNotify) destroy;
+ G_UNLOCK (qdata_mutex);
+
+ if (old_notify)
+ old_notify (old_data);
+}
+
+/**
+ * gst_mini_object_get_qdata:
+ * @object: The GstMiniObject to get a stored user data pointer from
+ * @quark: A #GQuark, naming the user data pointer
+ *
+ * This function gets back user data pointers stored via
+ * gst_mini_object_set_qdata().
+ *
+ * Returns: (transfer none): The user data pointer set, or %NULL
+ */
+gpointer
+gst_mini_object_get_qdata (GstMiniObject * object, GQuark quark)
+{
+ guint i;
+ gpointer result = NULL;
+
+ g_return_val_if_fail (object != NULL, NULL);
+ g_return_val_if_fail (quark > 0, NULL);
+
+ G_LOCK (qdata_mutex);
+ for (i = 0; i < object->n_qdata; i++) {
+ if (QDATA_QUARK (object, i) == quark) {
+ result = QDATA_DATA (object, i);
+ break;
+ }
+ }
+ G_UNLOCK (qdata_mutex);
+
+ return result;
}
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