gstreamer/gst/gstcontrolsource.c
Stefan Sauer 9a27b9c056 controller: move to core/gstobject
Move the controller to gstobject as a simple delegate. The controller and
controlsource are not classes in core. The controlsources stay separate as a lib
for now. This way we can avoid the qdata lookups.

Also remove controller_init(). There is no more need to link to controller for
elements.

Also sanitize the API. We now have functions to add properties like we had
methods to remove that. That avoids then ref count hacks we had in _new.
2011-11-04 20:11:51 +01:00

157 lines
4.9 KiB
C

/* GStreamer
*
* Copyright (C) 2007 Sebastian Dröge <slomo@circular-chaos.org>
*
* gstcontrolsource.c: Interface declaration 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstcontrolsource
* @short_description: base class for control source sources
*
* The #GstControlSource is a base class for control value sources that could
* be used by #GstController to get timestamp-value pairs.
*
* A #GstControlSource is used by first getting an instance, binding it to a
* #GParamSpec (for example by using gst_controller_set_control_source()) and
* then by having it used by the #GstController or calling
* gst_control_source_get_value() or gst_control_source_get_value_array().
*
* For implementing a new #GstControlSource one has to implement a
* #GstControlSourceBind method, which will depending on the #GParamSpec set up
* the control source for use and sets the #GstControlSourceGetValue and
* #GstControlSourceGetValueArray functions. These are then used by
* gst_control_source_get_value() or gst_control_source_get_value_array()
* to get values for specific timestamps.
*
*/
#include "gst_private.h"
#include <glib-object.h>
#include <gst/gst.h>
#include "gstcontrolsource.h"
#define GST_CAT_DEFAULT controller_debug
GST_DEBUG_CATEGORY_EXTERN (GST_CAT_DEFAULT);
G_DEFINE_ABSTRACT_TYPE (GstControlSource, gst_control_source, G_TYPE_OBJECT);
static GObjectClass *parent_class = NULL;
static void
gst_control_source_class_init (GstControlSourceClass * klass)
{
//GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
parent_class = g_type_class_peek_parent (klass);
/* Has to be implemented by children */
klass->bind = NULL;
}
static void
gst_control_source_init (GstControlSource * self)
{
/* Set default handlers that print a warning */
self->get_value = NULL;
self->get_value_array = NULL;
self->bound = FALSE;
}
/**
* gst_control_source_get_value:
* @self: the #GstControlSource object
* @timestamp: the time for which the value should be returned
* @value: the value
*
* Gets the value for this #GstControlSource at a given timestamp.
*
* Returns: FALSE if the value couldn't be returned, TRUE otherwise.
*/
gboolean
gst_control_source_get_value (GstControlSource * self, GstClockTime timestamp,
GValue * value)
{
g_return_val_if_fail (GST_IS_CONTROL_SOURCE (self), FALSE);
if (G_LIKELY (self->get_value)) {
return self->get_value (self, timestamp, value);
} else {
GST_ERROR ("Not bound to a specific property yet!");
return FALSE;
}
}
/**
* gst_control_source_get_value_array:
* @self: the #GstControlSource object
* @timestamp: the time that should be processed
* @value_array: array to put control-values in
*
* Gets an array of values for one element property.
*
* All fields of @value_array must be filled correctly. Especially the
* @value_array->values array must be big enough to keep the requested amount
* of values.
*
* The type of the values in the array is the same as the property's type.
*
* Returns: %TRUE if the given array could be filled, %FALSE otherwise
*/
gboolean
gst_control_source_get_value_array (GstControlSource * self,
GstClockTime timestamp, GstValueArray * value_array)
{
g_return_val_if_fail (GST_IS_CONTROL_SOURCE (self), FALSE);
if (G_LIKELY (self->get_value_array)) {
return self->get_value_array (self, timestamp, value_array);
} else {
GST_ERROR ("Not bound to a specific property yet!");
return FALSE;
}
}
/**
* gst_control_source_bind:
* @self: the #GstControlSource object
* @pspec: #GParamSpec for the property for which this #GstControlSource should generate values.
*
* Binds a #GstControlSource to a specific property. This must be called only once for a
* #GstControlSource.
*
* Returns: %TRUE if the #GstControlSource was bound correctly, %FALSE otherwise.
*/
gboolean
gst_control_source_bind (GstControlSource * self, GParamSpec * pspec)
{
gboolean ret = FALSE;
g_return_val_if_fail (GST_IS_CONTROL_SOURCE (self), FALSE);
g_return_val_if_fail (GST_CONTROL_SOURCE_GET_CLASS (self)->bind, FALSE);
g_return_val_if_fail (!self->bound, FALSE);
ret = GST_CONTROL_SOURCE_GET_CLASS (self)->bind (self, pspec);
if (ret)
self->bound = TRUE;
return ret;
}