gstreamer/gst/gstelementfactory.c

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/* 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.
*/
//#define DEBUG_ENABLED
#include "gst_private.h"
#include "gstelement.h"
#include "gstplugin.h"
/* global list of registered elementfactories */
GList* _gst_elementfactories;
void
_gst_elementfactory_initialize (void)
{
_gst_elementfactories = NULL;
}
/**
* gst_elementfactory_destroy:
* @elementfactory: factory to destroy
*
* Removes the elementfactory from the global list.
*/
void
gst_elementfactory_destroy (GstElementFactory *elementfactory)
{
g_return_if_fail (elementfactory != NULL);
_gst_elementfactories = g_list_remove (_gst_elementfactories, elementfactory);
// we don't free the struct bacause someone might have a handle to it..
}
/**
* gst_elementfactory_find:
* @name: name of factory to find
*
* Search for an elementfactory of the given name.
*
* Returns: #GstElementFactory if found, NULL otherwise
*/
GstElementFactory*
gst_elementfactory_find (const gchar *name)
{
GList *walk;
GstElementFactory *factory;
g_return_val_if_fail(name != NULL, NULL);
walk = _gst_elementfactories;
while (walk) {
factory = (GstElementFactory *)(walk->data);
if (!strcmp(name,factory->name))
return factory;
walk = g_list_next(walk);
}
// this should be an ERROR
GST_DEBUG (GST_CAT_ELEMENTFACTORY,"no such elementfactoryfactory \"%s\"\n", name);
return NULL;
}
/**
* gst_elementfactory_get_list:
*
* Get the global list of elementfactories.
*
* Returns: GList of type #GstElementFactory
*/
GList*
gst_elementfactory_get_list (void)
{
return _gst_elementfactories;
}
/**
* gst_elementfactory_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_elementfactory_new (const gchar *name, GType type,
GstElementDetails *details)
{
GstElementFactory *factory;
g_return_val_if_fail(name != NULL, NULL);
factory = g_new0(GstElementFactory, 1);
factory->name = g_strdup(name);
factory->type = type;
factory->details = details;
factory->padtemplates = NULL;
factory->numpadtemplates = 0;
_gst_elementfactories = g_list_prepend (_gst_elementfactories, factory);
return factory;
}
/**
* gst_elementfactory_create:
* @factory: factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given elementfactory.
* It wll be given the name supplied, since all elements require a name as
* their first argument.
*
* Returns: new #GstElement
*/
GstElement *
gst_elementfactory_create (GstElementFactory *factory,
const gchar *name)
{
GstElement *element;
GstElementClass *oclass;
g_return_val_if_fail(factory != NULL, NULL);
g_return_val_if_fail(name != NULL, NULL);
GST_DEBUG (GST_CAT_ELEMENTFACTORY,"creating element from factory \"%s\" with name \"%s\"\n",
factory->name, name);
// it's not loaded, try to load the plugin
if (factory->type == 0) {
factory = gst_plugin_load_elementfactory(factory->name);
}
g_return_val_if_fail(factory != NULL, NULL);
g_return_val_if_fail(factory->type != 0, NULL);
// create an instance of the element
element = GST_ELEMENT(g_object_new(factory->type,NULL));
g_assert(element != NULL);
// attempt to set the elemenfactory class pointer if necessary
oclass = GST_ELEMENT_CLASS(G_OBJECT_GET_CLASS(element));
if (oclass->elementfactory == NULL) {
GST_DEBUG (GST_CAT_ELEMENTFACTORY,"class %s\n", factory->name);
oclass->elementfactory = factory;
}
// copy pad template pointers to the element class
oclass->padtemplates = g_list_copy(factory->padtemplates);
oclass->numpadtemplates = factory->numpadtemplates;
gst_object_set_name (GST_OBJECT (element),name);
return element;
}
/**
* gst_elementfactory_make:
* @factoryname: a named factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given elementfactory.
* It wll be given the name supplied, since all elements require a name as
* their first argument.
*
* Returns: new #GstElement
*/
GstElement*
gst_elementfactory_make (const gchar *factoryname, const gchar *name)
{
GstElementFactory *factory;
GstElement *element;
g_return_val_if_fail(factoryname != NULL, NULL);
g_return_val_if_fail(name != NULL, NULL);
// GST_DEBUG (GST_CAT_ELEMENTFACTORY,"gstelementfactory: make \"%s\" \"%s\"\n", factoryname, name);
//gst_plugin_load_elementfactory(factoryname);
factory = gst_elementfactory_find(factoryname);
if (factory == NULL) return NULL;
element = gst_elementfactory_create(factory,name);
return element;
}
/**
* gst_elementfactory_add_padtemplate :
* @elementfactory: factory to add the src id to
* @templ: the padtemplate to add
*
* Add the given padtemplate to this elementfactory.
*/
void
gst_elementfactory_add_padtemplate (GstElementFactory *factory,
GstPadTemplate *templ)
{
g_return_if_fail(factory != NULL);
g_return_if_fail(templ != NULL);
factory->padtemplates = g_list_append (factory->padtemplates, templ);
factory->numpadtemplates++;
}
/**
* gst_elementfactory_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_elementfactory_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_check_compatibility (GST_PADTEMPLATE_CAPS (template), caps))
return TRUE;
}
templates = g_list_next (templates);
}
return FALSE;
}
/**
* gst_elementfactory_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_elementfactory_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_check_compatibility (caps, GST_PADTEMPLATE_CAPS (template)))
return TRUE;
}
templates = g_list_next (templates);
}
return FALSE;
}
/**
* gst_elementfactory_save_thyself:
* @factory: factory to save
* @parent: the parent xmlNodePtr
*
* Saves the factory into an XML tree.
*
* Returns: the new xmlNodePtr
*/
xmlNodePtr
gst_elementfactory_save_thyself (GstElementFactory *factory,
xmlNodePtr parent)
{
GList *pads;
g_return_val_if_fail(factory != NULL, NULL);
xmlNewChild(parent,NULL,"name",factory->name);
xmlNewChild(parent,NULL,"longname", factory->details->longname);
xmlNewChild(parent,NULL,"class", factory->details->klass);
xmlNewChild(parent,NULL,"description", factory->details->description);
xmlNewChild(parent,NULL,"version", factory->details->version);
xmlNewChild(parent,NULL,"author", factory->details->author);
xmlNewChild(parent,NULL,"copyright", factory->details->copyright);
pads = factory->padtemplates;
if (pads) {
while (pads) {
xmlNodePtr subtree;
GstPadTemplate *padtemplate = (GstPadTemplate *)pads->data;
subtree = xmlNewChild(parent, NULL, "padtemplate", NULL);
gst_padtemplate_save_thyself(padtemplate, subtree);
pads = g_list_next (pads);
}
}
return parent;
}
/**
* gst_elementfactory_load_thyself:
* @parent: the parent xmlNodePtr
*
* Creates a new factory from an xmlNodePtr.
*
* Returns: the new factory
*/
GstElementFactory *
gst_elementfactory_load_thyself (xmlNodePtr parent)
{
GstElementFactory *factory = g_new0(GstElementFactory, 1);
xmlNodePtr children = parent->xmlChildrenNode;
factory->details = g_new0(GstElementDetails, 1);
factory->padtemplates = NULL;
while (children) {
if (!strcmp(children->name, "name")) {
factory->name = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "longname")) {
factory->details->longname = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "class")) {
factory->details->klass = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "description")) {
factory->details->description = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "version")) {
factory->details->version = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "author")) {
factory->details->author = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "copyright")) {
factory->details->copyright = xmlNodeGetContent(children);
}
if (!strcmp(children->name, "padtemplate")) {
GstPadTemplate *template;
template = gst_padtemplate_load_thyself (children);
gst_elementfactory_add_padtemplate (factory, template);
}
children = children->next;
}
_gst_elementfactories = g_list_prepend (_gst_elementfactories, factory);
return factory;
}