gstreamer/gst/gstcontrolbinding.c
Mathieu Duponchelle 45d11f6590 docs: standardize GstContext, GstControlBinding documentation
* Document virtual methods in standalone comments, in order to properly
  annotate them

* Don't repeat what annotations are stating with respect to ownership
  transfer, nullability

* Mark GstControlBinding ABI field as private

* Misc cleanup / typo fixes / addition of links

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/758>
2021-02-15 15:27:14 +01:00

494 lines
15 KiB
C

/* GStreamer
*
* Copyright (C) 2011 Stefan Sauer <ensonic@users.sf.net>
*
* gstcontrolbinding.c: Attachment for control sources
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstcontrolbinding
* @title: GstControlBinding
* @short_description: attachment for control source sources
*
* A base class for value mapping objects that attaches control sources to #GObject
* properties. Such an object is taking one or more #GstControlSource instances,
* combines them and maps the resulting value to the type and value range of the
* bound property.
*/
/* FIXME(ensonic): should we make gst_object_add_control_binding() internal
* - we create the control_binding for a certain object anyway
* - we could call gst_object_add_control_binding() at the end of
* gst_control_binding_constructor()
* - the weak-ref on object is not nice, as is the same as gst_object_parent()
* once the object is added to the parent
*
* - another option would be to defer what is done in _constructor to when
* the parent is set (need to listen to the signal then)
* then basically I could
* a) remove the obj arg and wait the binding to be added or
* b) add the binding from constructor, unref object there and make obj
* writeonly
*/
#include "gst_private.h"
#include <glib-object.h>
#include <gst/gst.h>
#include "gstcontrolbinding.h"
#include <math.h>
struct _GstControlBindingPrivate
{
GWeakRef object;
};
#define GST_CAT_DEFAULT control_binding_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
#define _do_init \
GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "gstcontrolbinding", 0, \
"dynamic parameter control source attachment");
static GObject *gst_control_binding_constructor (GType type,
guint n_construct_params, GObjectConstructParam * construct_params);
static void gst_control_binding_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_control_binding_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_control_binding_dispose (GObject * object);
static void gst_control_binding_finalize (GObject * object);
G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GstControlBinding, gst_control_binding,
GST_TYPE_OBJECT, G_ADD_PRIVATE (GstControlBinding) _do_init);
enum
{
PROP_0,
PROP_OBJECT,
PROP_NAME,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
gst_control_binding_class_init (GstControlBindingClass * klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->constructor = gst_control_binding_constructor;
gobject_class->set_property = gst_control_binding_set_property;
gobject_class->get_property = gst_control_binding_get_property;
gobject_class->dispose = gst_control_binding_dispose;
gobject_class->finalize = gst_control_binding_finalize;
properties[PROP_OBJECT] =
g_param_spec_object ("object", "Object",
"The object of the property", GST_TYPE_OBJECT,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS);
properties[PROP_NAME] =
g_param_spec_string ("name", "Name", "The name of the property", NULL,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS);
g_object_class_install_properties (gobject_class, PROP_LAST, properties);
}
static void
gst_control_binding_init (GstControlBinding * binding)
{
binding->ABI.abi.priv = gst_control_binding_get_instance_private (binding);
g_weak_ref_init (&binding->ABI.abi.priv->object, NULL);
}
static GObject *
gst_control_binding_constructor (GType type, guint n_construct_params,
GObjectConstructParam * construct_params)
{
GstControlBinding *binding;
GParamSpec *pspec;
GstObject *object;
binding =
GST_CONTROL_BINDING (G_OBJECT_CLASS (gst_control_binding_parent_class)
->constructor (type, n_construct_params, construct_params));
object = g_weak_ref_get (&binding->ABI.abi.priv->object);
if (!object) {
GST_WARNING_OBJECT (object, "no object set");
return (GObject *) binding;
}
GST_INFO_OBJECT (object, "trying to put property '%s' under control",
binding->name);
/* check if the object has a property of that name */
if ((pspec =
g_object_class_find_property (G_OBJECT_GET_CLASS (object),
binding->name))) {
GST_DEBUG_OBJECT (object, " psec->flags : 0x%08x", pspec->flags);
/* check if this param is writeable && controllable && !construct-only */
if ((pspec->flags & (G_PARAM_WRITABLE | GST_PARAM_CONTROLLABLE |
G_PARAM_CONSTRUCT_ONLY)) ==
(G_PARAM_WRITABLE | GST_PARAM_CONTROLLABLE)) {
binding->pspec = pspec;
} else {
GST_WARNING_OBJECT (object,
"property '%s' on class '%s' needs to "
"be writeable, controllable and not construct_only", binding->name,
G_OBJECT_TYPE_NAME (object));
}
} else {
GST_WARNING_OBJECT (object, "class '%s' has no property '%s'",
G_OBJECT_TYPE_NAME (object), binding->name);
}
gst_object_unref (object);
return (GObject *) binding;
}
static void
gst_control_binding_dispose (GObject * object)
{
GstControlBinding *self = GST_CONTROL_BINDING (object);
/* we did not took a reference */
if (self->__object)
g_object_remove_weak_pointer ((GObject *) self->__object,
(gpointer *) & self->__object);
self->__object = NULL;
g_weak_ref_clear (&self->ABI.abi.priv->object);
((GObjectClass *) gst_control_binding_parent_class)->dispose (object);
}
static void
gst_control_binding_finalize (GObject * object)
{
GstControlBinding *self = GST_CONTROL_BINDING (object);
g_free (self->name);
((GObjectClass *) gst_control_binding_parent_class)->finalize (object);
}
static void
gst_control_binding_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstControlBinding *self = GST_CONTROL_BINDING (object);
switch (prop_id) {
case PROP_OBJECT:
/* do not ref to avoid a ref cycle */
self->__object = g_value_get_object (value);
g_object_add_weak_pointer ((GObject *) self->__object,
(gpointer *) & self->__object);
g_weak_ref_set (&self->ABI.abi.priv->object, self->__object);
break;
case PROP_NAME:
self->name = g_value_dup_string (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_control_binding_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstControlBinding *self = GST_CONTROL_BINDING (object);
switch (prop_id) {
case PROP_OBJECT:
g_value_take_object (value, g_weak_ref_get (&self->ABI.abi.priv->object));
break;
case PROP_NAME:
g_value_set_string (value, self->name);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/* functions */
/**
* gst_control_binding_sync_values:
* @binding: the control binding
* @object: the object that has controlled properties
* @timestamp: the time that should be processed
* @last_sync: the last time this was called
*
* Sets the property of the @object, according to the #GstControlSources that
* handles it and for the given timestamp.
*
* If this function fails, it is most likely the application developers fault.
* Most probably the control sources are not setup correctly.
*
* Returns: %TRUE if the controller value could be applied to the object
* property, %FALSE otherwise
*/
gboolean
gst_control_binding_sync_values (GstControlBinding * binding,
GstObject * object, GstClockTime timestamp, GstClockTime last_sync)
{
GstControlBindingClass *klass;
gboolean ret = FALSE;
g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
if (binding->disabled)
return TRUE;
klass = GST_CONTROL_BINDING_GET_CLASS (binding);
if (G_LIKELY (klass->sync_values != NULL)) {
ret = klass->sync_values (binding, object, timestamp, last_sync);
} else {
GST_WARNING_OBJECT (binding, "missing sync_values implementation");
}
return ret;
}
/**
* gst_control_binding_get_value:
* @binding: the control binding
* @timestamp: the time the control-change should be read from
*
* Gets the value for the given controlled property at the requested time.
*
* Returns: (nullable): the GValue of the property at the given time,
* or %NULL if the property isn't controlled.
*/
GValue *
gst_control_binding_get_value (GstControlBinding * binding,
GstClockTime timestamp)
{
GstControlBindingClass *klass;
GValue *ret = NULL;
g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), NULL);
g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), NULL);
klass = GST_CONTROL_BINDING_GET_CLASS (binding);
if (G_LIKELY (klass->get_value != NULL)) {
ret = klass->get_value (binding, timestamp);
} else {
GST_WARNING_OBJECT (binding, "missing get_value implementation");
}
return ret;
}
/**
* gst_control_binding_get_value_array: (skip)
* @binding: the control binding
* @timestamp: the time that should be processed
* @interval: the time spacing between subsequent values
* @n_values: the number of values
* @values: (array length=n_values): array to put control-values in
*
* Gets a number of values for the given controlled property starting at the
* requested time. The array @values needs to hold enough space for @n_values of
* the same type as the objects property's type.
*
* This function is useful if one wants to e.g. draw a graph of the control
* curve or apply a control curve sample by sample.
*
* The values are unboxed and ready to be used. The similar function
* gst_control_binding_get_g_value_array() returns the array as #GValues and is
* more suitable for bindings.
*
* Returns: %TRUE if the given array could be filled, %FALSE otherwise
*/
gboolean
gst_control_binding_get_value_array (GstControlBinding * binding,
GstClockTime timestamp, GstClockTime interval, guint n_values,
gpointer values)
{
GstControlBindingClass *klass;
gboolean ret = FALSE;
g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), FALSE);
g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), FALSE);
g_return_val_if_fail (values, FALSE);
klass = GST_CONTROL_BINDING_GET_CLASS (binding);
if (G_LIKELY (klass->get_value_array != NULL)) {
ret =
klass->get_value_array (binding, timestamp, interval, n_values, values);
} else {
GST_WARNING_OBJECT (binding, "missing get_value_array implementation");
}
return ret;
}
#define CONVERT_ARRAY(type,TYPE) \
{ \
g##type *v = g_new (g##type,n_values); \
ret = gst_control_binding_get_value_array (binding, timestamp, interval, \
n_values, v); \
if (ret) { \
for (i = 0; i < n_values; i++) { \
g_value_init (&values[i], G_TYPE_##TYPE); \
g_value_set_##type (&values[i], v[i]); \
} \
} \
g_free (v); \
}
/**
* gst_control_binding_get_g_value_array:
* @binding: the control binding
* @timestamp: the time that should be processed
* @interval: the time spacing between subsequent values
* @n_values: the number of values
* @values: (array length=n_values): array to put control-values in
*
* Gets a number of #GValues for the given controlled property starting at the
* requested time. The array @values need to hold enough space for @n_values of
* #GValue.
*
* This function is useful if one wants to e.g. draw a graph of the control
* curve or apply a control curve sample by sample.
*
* Returns: %TRUE if the given array could be filled, %FALSE otherwise
*/
gboolean
gst_control_binding_get_g_value_array (GstControlBinding * binding,
GstClockTime timestamp, GstClockTime interval, guint n_values,
GValue * values)
{
GstControlBindingClass *klass;
gboolean ret = FALSE;
g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), FALSE);
g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (timestamp), FALSE);
g_return_val_if_fail (GST_CLOCK_TIME_IS_VALID (interval), FALSE);
g_return_val_if_fail (values, FALSE);
klass = GST_CONTROL_BINDING_GET_CLASS (binding);
if (G_LIKELY (klass->get_g_value_array != NULL)) {
ret =
klass->get_g_value_array (binding, timestamp, interval, n_values,
values);
} else {
guint i;
GType type, base;
base = type = G_PARAM_SPEC_VALUE_TYPE (GST_CONTROL_BINDING_PSPEC (binding));
while ((type = g_type_parent (type)))
base = type;
GST_INFO_OBJECT (binding, "missing get_g_value_array implementation, we're "
"emulating it");
switch (base) {
case G_TYPE_INT:
CONVERT_ARRAY (int, INT);
break;
case G_TYPE_UINT:
CONVERT_ARRAY (uint, UINT);
break;
case G_TYPE_LONG:
CONVERT_ARRAY (long, LONG);
break;
case G_TYPE_ULONG:
CONVERT_ARRAY (ulong, ULONG);
break;
case G_TYPE_INT64:
CONVERT_ARRAY (int64, INT64);
break;
case G_TYPE_UINT64:
CONVERT_ARRAY (uint64, UINT64);
break;
case G_TYPE_FLOAT:
CONVERT_ARRAY (float, FLOAT);
break;
case G_TYPE_DOUBLE:
CONVERT_ARRAY (double, DOUBLE);
break;
case G_TYPE_BOOLEAN:
CONVERT_ARRAY (boolean, BOOLEAN);
break;
case G_TYPE_ENUM:
{
gint *v = g_new (gint, n_values);
ret = gst_control_binding_get_value_array (binding, timestamp, interval,
n_values, v);
if (ret) {
for (i = 0; i < n_values; i++) {
g_value_init (&values[i], type);
g_value_set_enum (&values[i], v[i]);
}
}
g_free (v);
}
break;
default:
GST_WARNING ("incomplete implementation for paramspec type '%s'",
G_PARAM_SPEC_TYPE_NAME (GST_CONTROL_BINDING_PSPEC (binding)));
GST_CONTROL_BINDING_PSPEC (binding) = NULL;
break;
}
}
return ret;
}
/**
* gst_control_binding_set_disabled:
* @binding: the control binding
* @disabled: boolean that specifies whether to disable the controller
* or not.
*
* This function is used to disable a control binding for some time, i.e.
* gst_object_sync_values() will do nothing.
*/
void
gst_control_binding_set_disabled (GstControlBinding * binding,
gboolean disabled)
{
g_return_if_fail (GST_IS_CONTROL_BINDING (binding));
binding->disabled = disabled;
}
/**
* gst_control_binding_is_disabled:
* @binding: the control binding
*
* Checks if the control binding is disabled.
*
* Returns: %TRUE if the binding is inactive
*/
gboolean
gst_control_binding_is_disabled (GstControlBinding * binding)
{
g_return_val_if_fail (GST_IS_CONTROL_BINDING (binding), TRUE);
return ! !binding->disabled;
}