gstreamer/gst/gstelementfactory.c

418 lines
11 KiB
C
Raw Normal View History

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstelementfactory.c: GstElementFactory object, support routines
*
* 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.
*/
#include "gst_private.h"
#include "gstelement.h"
#include "gstregistrypool.h"
#include "gstinfo.h"
#define GST_CAT_DEFAULT GST_CAT_ELEMENT_FACTORY
static void gst_element_factory_class_init (GstElementFactoryClass *klass);
static void gst_element_factory_init (GstElementFactory *factory);
static void gst_element_factory_unload_thyself (GstPluginFeature *feature);
static GstPluginFeatureClass *parent_class = NULL;
/* static guint gst_element_factory_signals[LAST_SIGNAL] = { 0 }; */
GType
gst_element_factory_get_type (void)
{
static GType elementfactory_type = 0;
if (!elementfactory_type) {
static const GTypeInfo elementfactory_info = {
sizeof (GstElementFactoryClass),
NULL,
NULL,
(GClassInitFunc) gst_element_factory_class_init,
NULL,
NULL,
sizeof(GstElementFactory),
0,
(GInstanceInitFunc) gst_element_factory_init,
NULL
};
elementfactory_type = g_type_register_static (GST_TYPE_PLUGIN_FEATURE,
"GstElementFactory", &elementfactory_info, 0);
}
return elementfactory_type;
}
static void
gst_element_factory_class_init (GstElementFactoryClass *klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstPluginFeatureClass *gstpluginfeature_class;
gobject_class = (GObjectClass*)klass;
gstobject_class = (GstObjectClass*)klass;
gstpluginfeature_class = (GstPluginFeatureClass*) klass;
parent_class = g_type_class_ref (GST_TYPE_PLUGIN_FEATURE);
gstpluginfeature_class->unload_thyself = GST_DEBUG_FUNCPTR (gst_element_factory_unload_thyself);
}
static void
gst_element_factory_init (GstElementFactory *factory)
{
factory->padtemplates = NULL;
factory->numpadtemplates = 0;
}
/**
* gst_element_factory_find:
* @name: name of factory to find
*
* Search for an element factory of the given name.
*
* Returns: #GstElementFactory if found, NULL otherwise
*/
GstElementFactory*
gst_element_factory_find (const gchar *name)
{
GstPluginFeature *feature;
g_return_val_if_fail(name != NULL, NULL);
feature = gst_registry_pool_find_feature (name, GST_TYPE_ELEMENT_FACTORY);
if (feature)
return GST_ELEMENT_FACTORY (feature);
/* this should be an ERROR */
GST_DEBUG ("no such elementfactory \"%s\"", name);
return NULL;
}
static void
gst_element_details_free (GstElementDetails *dp)
{
g_free (dp->longname);
g_free (dp->klass);
g_free (dp->license);
g_free (dp->description);
g_free (dp->version);
g_free (dp->author);
g_free (dp->copyright);
g_free (dp);
}
static void
gst_element_factory_cleanup (GstElementFactory *factory)
{
GList *padtemplates;
if (factory->details_dynamic) {
gst_element_details_free (factory->details);
factory->details_dynamic = FALSE;
}
padtemplates = factory->padtemplates;
while (padtemplates) {
GstPadTemplate *oldtempl = GST_PAD_TEMPLATE (padtemplates->data);
gst_object_unref (GST_OBJECT (oldtempl));
padtemplates = g_list_next (padtemplates);
}
g_list_free (factory->padtemplates);
factory->padtemplates = NULL;
factory->numpadtemplates = 0;
g_free (GST_PLUGIN_FEATURE (factory)->name);
}
/**
* gst_element_factory_new:
* @name: name of new elementfactory
* @type: GType of new element
* @details: #GstElementDetails structure with element details
*
* Create a new elementfactory capable of insantiating objects of the
* given type.
*
* Returns: new elementfactory
*/
GstElementFactory*
gst_element_factory_new (const gchar *name, GType type,
GstElementDetails *details)
{
GstElementFactory *factory;
g_return_val_if_fail (name != NULL, NULL);
g_return_val_if_fail (type, NULL);
g_return_val_if_fail (details, NULL);
g_return_val_if_fail (details->longname, NULL);
g_return_val_if_fail (details->klass, NULL);
g_return_val_if_fail (details->license, NULL);
g_return_val_if_fail (details->description, NULL);
g_return_val_if_fail (details->version, NULL);
g_return_val_if_fail (details->author, NULL);
g_return_val_if_fail (details->copyright, NULL);
factory = gst_element_factory_find (name);
if (!factory)
factory = GST_ELEMENT_FACTORY (g_object_new (GST_TYPE_ELEMENT_FACTORY, NULL));
else {
gst_element_factory_cleanup (factory);
}
factory->details = details;
factory->details_dynamic = FALSE;
if (!factory->type)
factory->type = type;
else if (factory->type != type)
g_critical ("`%s' requested type change (!)", name);
GST_PLUGIN_FEATURE (factory)->name = g_strdup (name);
return factory;
}
/**
* gst_element_factory_create:
* @factory: factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given elementfactory.
* It will be given the name supplied, since all elements require a name as
* their first argument.
*
* Returns: new #GstElement
*/
GstElement*
gst_element_factory_create (GstElementFactory *factory,
const gchar *name)
{
GstElement *element;
GstElementClass *oclass;
g_return_val_if_fail (factory != NULL, NULL);
if (!gst_plugin_feature_ensure_loaded (GST_PLUGIN_FEATURE (factory))) {
GST_INFO ("could not load element factory for element \"%s\"", name);
return NULL;
}
GST_LOG ("creating element from factory \"%s\" (name \"%s\", type %d)",
GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name), (gint) factory->type);
if (factory->type == 0) {
g_critical ("Factory for `%s' has no type",
GST_PLUGIN_FEATURE_NAME (factory));
return NULL;
}
/* attempt to set the elementfactory class pointer if necessary */
oclass = GST_ELEMENT_CLASS (g_type_class_ref (factory->type));
if (oclass->elementfactory == NULL) {
GST_DEBUG ("class %s", GST_PLUGIN_FEATURE_NAME (factory));
oclass->elementfactory = factory;
/* copy pad template pointers to the element class,
* allow for custom padtemplates */
oclass->padtemplates = g_list_concat (oclass->padtemplates,
g_list_copy (factory->padtemplates));
oclass->numpadtemplates += factory->numpadtemplates;
}
/* create an instance of the element */
element = GST_ELEMENT (g_object_new (factory->type, NULL));
g_assert (element != NULL);
g_type_class_unref (oclass);
gst_object_set_name (GST_OBJECT (element), name);
return element;
}
/**
* gst_element_factory_make:
* @factoryname: a named factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given element factory.
* If name is NULL, then the element will receive a guaranteed unique name,
* consisting of the element factory name and a number.
* If name is given, it will be given the name supplied.
*
* Returns: new #GstElement (or NULL if unable to create element)
*/
GstElement*
gst_element_factory_make (const gchar *factoryname, const gchar *name)
{
GstElementFactory *factory;
GstElement *element;
g_return_val_if_fail (factoryname != NULL, NULL);
GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
factoryname, GST_STR_NULL (name));
/* gst_plugin_load_element_factory (factoryname); */
factory = gst_element_factory_find (factoryname);
if (factory == NULL) {
GST_INFO ("no such element factory \"%s\"!",
factoryname);
return NULL;
}
element = gst_element_factory_create (factory, name);
if (element == NULL) {
GST_INFO ("couldn't create instance of element factory \"%s\"!",
factoryname);
return NULL;
}
return element;
}
/**
* gst_element_factory_make_or_warn:
* @factoryname: a named factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given element factory
* using #gst_element_factory_make.
* Will use g_warning if the element could not be created.
*
* Returns: new #GstElement (or NULL if unable to create element)
*/
GstElement*
gst_element_factory_make_or_warn (const gchar *factoryname, const gchar *name)
{
GstElement *element;
element = gst_element_factory_make (factoryname, name);
if (element == NULL)
g_warning ("Could not create element from factory %s !\n", factoryname);
return element;
}
/**
* gst_element_factory_add_pad_template :
* @elementfactory: factory to add the src id to
* @templ: the padtemplate to add
*
* Add the given padtemplate to this elementfactory.
*/
void
gst_element_factory_add_pad_template (GstElementFactory *factory,
GstPadTemplate *templ)
{
g_return_if_fail (factory != NULL);
g_return_if_fail (templ != NULL);
gst_object_ref (GST_OBJECT (templ));
gst_object_sink (GST_OBJECT (templ));
factory->padtemplates = g_list_append (factory->padtemplates, templ);
factory->numpadtemplates++;
}
/**
* gst_element_factory_can_src_caps :
* @factory: factory to query
* @caps: the caps to check
*
* Checks if the factory can source the given capability.
*
* Returns: true if it can src the capabilities
*/
gboolean
gst_element_factory_can_src_caps (GstElementFactory *factory,
GstCaps *caps)
{
GList *templates;
g_return_val_if_fail(factory != NULL, FALSE);
g_return_val_if_fail(caps != NULL, FALSE);
templates = factory->padtemplates;
while (templates) {
GstPadTemplate *template = (GstPadTemplate *)templates->data;
if (template->direction == GST_PAD_SRC) {
if (gst_caps_is_always_compatible (GST_PAD_TEMPLATE_CAPS (template), caps))
return TRUE;
}
templates = g_list_next (templates);
}
return FALSE;
}
/**
* gst_element_factory_can_sink_caps :
* @factory: factory to query
* @caps: the caps to check
*
* Checks if the factory can sink the given capability.
*
* Returns: true if it can sink the capabilities
*/
gboolean
gst_element_factory_can_sink_caps (GstElementFactory *factory,
GstCaps *caps)
{
GList *templates;
g_return_val_if_fail(factory != NULL, FALSE);
g_return_val_if_fail(caps != NULL, FALSE);
templates = factory->padtemplates;
while (templates) {
GstPadTemplate *template = (GstPadTemplate *)templates->data;
if (template->direction == GST_PAD_SINK) {
if (gst_caps_is_always_compatible (caps, GST_PAD_TEMPLATE_CAPS (template)))
return TRUE;
}
templates = g_list_next (templates);
}
return FALSE;
}
static void
gst_element_factory_unload_thyself (GstPluginFeature *feature)
{
GstElementFactory *factory;
factory = GST_ELEMENT_FACTORY (feature);
factory->type = 0;
}