gstreamer/gst/gstdevice.c
Sebastian Dröge 341ee45155 device: Enforce that elements created by gst_device_create_element() are floating
Bindings might have a hard time making sure that the reference is indeed
still floating after returning here.

See https://gitlab.freedesktop.org/gstreamer/gstreamer/issues/444
2019-09-12 09:50:17 +00:00

413 lines
11 KiB
C

/* GStreamer
* Copyright (C) 2012 Olivier Crete <olivier.crete@collabora.com>
*
* gstdevice.c: Device discovery
*
* 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:gstdevice
* @title: GstDevice
* @short_description: Object representing a device
* @see_also: #GstDeviceProvider
*
* #GstDevice are objects representing a device, they contain
* relevant metadata about the device, such as its class and the #GstCaps
* representing the media types it can produce or handle.
*
* #GstDevice are created by #GstDeviceProvider objects which can be
* aggregated by #GstDeviceMonitor objects.
*
* Since: 1.4
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gst_private.h"
#include "gstdevice.h"
enum
{
PROP_DISPLAY_NAME = 1,
PROP_CAPS,
PROP_DEVICE_CLASS,
PROP_PROPERTIES
};
enum
{
REMOVED,
LAST_SIGNAL
};
struct _GstDevicePrivate
{
GstCaps *caps;
gchar *device_class;
gchar *display_name;
GstStructure *properties;
};
static guint signals[LAST_SIGNAL];
G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GstDevice, gst_device, GST_TYPE_OBJECT);
static void gst_device_get_property (GObject * object, guint property_id,
GValue * value, GParamSpec * pspec);
static void gst_device_set_property (GObject * object, guint property_id,
const GValue * value, GParamSpec * pspec);
static void gst_device_finalize (GObject * object);
static void
gst_device_class_init (GstDeviceClass * klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->get_property = gst_device_get_property;
object_class->set_property = gst_device_set_property;
object_class->finalize = gst_device_finalize;
g_object_class_install_property (object_class, PROP_DISPLAY_NAME,
g_param_spec_string ("display-name", "Display Name",
"The user-friendly name of the device", "",
G_PARAM_STATIC_STRINGS | G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
g_object_class_install_property (object_class, PROP_CAPS,
g_param_spec_boxed ("caps", "Device Caps",
"The possible caps of a device", GST_TYPE_CAPS,
G_PARAM_STATIC_STRINGS | G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
g_object_class_install_property (object_class, PROP_DEVICE_CLASS,
g_param_spec_string ("device-class", "Device Class",
"The Class of the device", "",
G_PARAM_STATIC_STRINGS | G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
g_object_class_install_property (object_class, PROP_PROPERTIES,
g_param_spec_boxed ("properties", "Properties",
"The extra properties of the device", GST_TYPE_STRUCTURE,
G_PARAM_STATIC_STRINGS | G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
signals[REMOVED] = g_signal_new ("removed", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL, G_TYPE_NONE, 0);
}
static void
gst_device_init (GstDevice * device)
{
device->priv = gst_device_get_instance_private (device);
}
static void
gst_device_finalize (GObject * object)
{
GstDevice *device = GST_DEVICE (object);
gst_caps_replace (&device->priv->caps, NULL);
if (device->priv->properties)
gst_structure_free (device->priv->properties);
g_free (device->priv->display_name);
g_free (device->priv->device_class);
G_OBJECT_CLASS (gst_device_parent_class)->finalize (object);
}
static void
gst_device_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstDevice *gstdevice;
gstdevice = GST_DEVICE_CAST (object);
switch (prop_id) {
case PROP_DISPLAY_NAME:
g_value_take_string (value, gst_device_get_display_name (gstdevice));
break;
case PROP_CAPS:
if (gstdevice->priv->caps)
g_value_take_boxed (value, gst_device_get_caps (gstdevice));
break;
case PROP_DEVICE_CLASS:
g_value_take_string (value, gst_device_get_device_class (gstdevice));
break;
case PROP_PROPERTIES:
if (gstdevice->priv->properties)
g_value_take_boxed (value, gst_device_get_properties (gstdevice));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_device_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstDevice *gstdevice;
gstdevice = GST_DEVICE_CAST (object);
switch (prop_id) {
case PROP_DISPLAY_NAME:
gstdevice->priv->display_name = g_value_dup_string (value);
break;
case PROP_CAPS:
gst_caps_replace (&gstdevice->priv->caps, g_value_get_boxed (value));
break;
case PROP_DEVICE_CLASS:
gstdevice->priv->device_class = g_value_dup_string (value);
break;
case PROP_PROPERTIES:
if (gstdevice->priv->properties)
gst_structure_free (gstdevice->priv->properties);
gstdevice->priv->properties = g_value_dup_boxed (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/**
* gst_device_create_element:
* @device: a #GstDevice
* @name: (allow-none): name of new element, or %NULL to automatically
* create a unique name.
*
* Creates the element with all of the required parameters set to use
* this device.
*
* Returns: (transfer floating) (nullable): a new #GstElement configured to use
* this device
*
* Since: 1.4
*/
GstElement *
gst_device_create_element (GstDevice * device, const gchar * name)
{
GstDeviceClass *klass = GST_DEVICE_GET_CLASS (device);
GstElement *element = NULL;
g_return_val_if_fail (GST_IS_DEVICE (device), NULL);
if (klass->create_element)
element = klass->create_element (device, name);
/* Ensure that the reference is floating. Bindings might have a hard time
* making sure that the reference is indeed still floating after returning
* here */
if (element)
g_object_force_floating ((GObject *) element);
return element;
}
/**
* gst_device_get_caps:
* @device: a #GstDevice
*
* Getter for the #GstCaps that this device supports.
*
* Returns: (nullable): The #GstCaps supported by this device. Unref with
* gst_caps_unref() when done.
*
* Since: 1.4
*/
GstCaps *
gst_device_get_caps (GstDevice * device)
{
g_return_val_if_fail (GST_IS_DEVICE (device), NULL);
if (device->priv->caps)
return gst_caps_ref (device->priv->caps);
else
return NULL;
}
/**
* gst_device_get_display_name:
* @device: a #GstDevice
*
* Gets the user-friendly name of the device.
*
* Returns: The device name. Free with g_free() after use.
*
* Since: 1.4
*/
gchar *
gst_device_get_display_name (GstDevice * device)
{
g_return_val_if_fail (GST_IS_DEVICE (device), NULL);
return
g_strdup (device->priv->display_name ? device->priv->display_name : "");
}
/**
* gst_device_get_device_class:
* @device: a #GstDevice
*
* Gets the "class" of a device. This is a "/" separated list of
* classes that represent this device. They are a subset of the
* classes of the #GstDeviceProvider that produced this device.
*
* Returns: The device class. Free with g_free() after use.
*
* Since: 1.4
*/
gchar *
gst_device_get_device_class (GstDevice * device)
{
g_return_val_if_fail (GST_IS_DEVICE (device), NULL);
if (device->priv->device_class != NULL)
return g_strdup (device->priv->device_class);
else
return g_strdup ("");
}
/**
* gst_device_get_properties:
* @device: a #GstDevice
*
* Gets the extra properties of a device.
*
* Returns: (nullable): The extra properties or %NULL when there are none.
* Free with gst_structure_free() after use.
*
* Since: 1.6
*/
GstStructure *
gst_device_get_properties (GstDevice * device)
{
g_return_val_if_fail (GST_IS_DEVICE (device), NULL);
if (device->priv->properties != NULL)
return gst_structure_copy (device->priv->properties);
else
return NULL;
}
/**
* gst_device_reconfigure_element:
* @device: a #GstDevice
* @element: a #GstElement
*
* Tries to reconfigure an existing element to use the device. If this
* function fails, then one must destroy the element and create a new one
* using gst_device_create_element().
*
* Note: This should only be implemented for elements can change their
* device in the PLAYING state.
*
* Returns: %TRUE if the element could be reconfigured to use this device,
* %FALSE otherwise.
*
* Since: 1.4
*/
gboolean
gst_device_reconfigure_element (GstDevice * device, GstElement * element)
{
GstDeviceClass *klass = GST_DEVICE_GET_CLASS (device);
g_return_val_if_fail (GST_IS_DEVICE (device), FALSE);
if (klass->reconfigure_element)
return klass->reconfigure_element (device, element);
else
return FALSE;
}
/**
* gst_device_has_classesv:
* @device: a #GstDevice
* @classes: (array zero-terminated=1): a %NULL terminated array of classes
* to match, only match if all classes are matched
*
* Check if @factory matches all of the given classes
*
* Returns: %TRUE if @device matches.
*
* Since: 1.4
*/
gboolean
gst_device_has_classesv (GstDevice * device, gchar ** classes)
{
g_return_val_if_fail (GST_IS_DEVICE (device), FALSE);
if (!classes)
return TRUE;
for (; classes[0]; classes++) {
const gchar *klass = classes[0];
const gchar *found;
guint len;
if (*klass == '\0')
continue;
found = strstr (device->priv->device_class, klass);
if (!found)
return FALSE;
if (found != device->priv->device_class && *(found - 1) != '/')
return FALSE;
len = strlen (klass);
if (found[len] != 0 && found[len] != '/')
return FALSE;
}
return TRUE;
}
/**
* gst_device_has_classes:
* @device: a #GstDevice
* @classes: a "/"-separated list of device classes to match, only match if
* all classes are matched
*
* Check if @device matches all of the given classes
*
* Returns: %TRUE if @device matches.
*
* Since: 1.4
*/
gboolean
gst_device_has_classes (GstDevice * device, const gchar * classes)
{
gchar **classesv;
gboolean res;
g_return_val_if_fail (GST_IS_DEVICE (device), FALSE);
if (!classes)
return TRUE;
classesv = g_strsplit (classes, "/", 0);
res = gst_device_has_classesv (device, classesv);
g_strfreev (classesv);
return res;
}