2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
4 * 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
6 * gstelementfactory.c: GstElementFactory object, support routines
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
25 * SECTION:gstelementfactory
26 * @short_description: Create GstElements from a factory
27 * @see_also: #GstElement, #GstPlugin, #GstPluginFeature, #GstPadTemplate.
29 * #GstElementFactory is used to create instances of elements. A
30 * GstElementfactory can be added to a #GstPlugin as it is also a
33 * Use the gst_element_factory_find() and gst_element_factory_create()
34 * functions to create element instances or use gst_element_factory_make() as a
35 * convenient shortcut.
37 * The following code example shows you how to create a GstFileSrc element.
40 * <title>Using an element factory</title>
41 * <programlisting language="c">
42 * #include <gst/gst.h>
45 * GstElementFactory *srcfactory;
47 * gst_init (&argc, &argv);
49 * srcfactory = gst_element_factory_find ("filesrc");
50 * g_return_if_fail (srcfactory != NULL);
51 * src = gst_element_factory_create (srcfactory, "src");
52 * g_return_if_fail (src != NULL);
57 * Last reviewed on 2005-11-23 (0.9.5)
60 #include "gst_private.h"
62 #include "gstelement.h"
65 #include "gstregistry.h"
67 #include "glib-compat-private.h"
69 GST_DEBUG_CATEGORY_STATIC (element_factory_debug);
70 #define GST_CAT_DEFAULT element_factory_debug
72 static void gst_element_factory_class_init (GstElementFactoryClass * klass);
73 static void gst_element_factory_init (GstElementFactory * factory);
74 static void gst_element_factory_finalize (GObject * object);
75 void __gst_element_details_clear (GstElementDetails * dp);
76 static void gst_element_factory_cleanup (GstElementFactory * factory);
78 static GstPluginFeatureClass *parent_class = NULL;
80 /* static guint gst_element_factory_signals[LAST_SIGNAL] = { 0 }; */
83 gst_element_factory_get_type (void)
85 static GType elementfactory_type = 0;
87 if (G_UNLIKELY (elementfactory_type == 0)) {
88 static const GTypeInfo elementfactory_info = {
89 sizeof (GstElementFactoryClass),
92 (GClassInitFunc) gst_element_factory_class_init,
95 sizeof (GstElementFactory),
97 (GInstanceInitFunc) gst_element_factory_init,
101 elementfactory_type = g_type_register_static (GST_TYPE_PLUGIN_FEATURE,
102 "GstElementFactory", &elementfactory_info, 0);
103 GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY",
104 GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED,
105 "element factories keep information about installed elements");
107 return elementfactory_type;
110 gst_element_factory_class_init (GstElementFactoryClass * klass)
112 GObjectClass *gobject_class;
114 gobject_class = (GObjectClass *) klass;
116 parent_class = g_type_class_peek_parent (klass);
118 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_factory_finalize);
122 gst_element_factory_init (GstElementFactory * factory)
124 factory->staticpadtemplates = NULL;
125 factory->numpadtemplates = 0;
127 factory->uri_type = GST_URI_UNKNOWN;
128 factory->uri_protocols = NULL;
130 factory->interfaces = NULL;
134 gst_element_factory_finalize (GObject * object)
136 GstElementFactory *factory = GST_ELEMENT_FACTORY (object);
138 gst_element_factory_cleanup (factory);
139 G_OBJECT_CLASS (parent_class)->finalize (object);
143 * gst_element_factory_find:
144 * @name: name of factory to find
146 * Search for an element factory of the given name. Refs the returned
147 * element factory; caller is responsible for unreffing.
149 * Returns: #GstElementFactory if found, NULL otherwise
152 gst_element_factory_find (const gchar * name)
154 GstPluginFeature *feature;
156 g_return_val_if_fail (name != NULL, NULL);
158 feature = gst_registry_find_feature (gst_registry_get_default (), name,
159 GST_TYPE_ELEMENT_FACTORY);
161 return GST_ELEMENT_FACTORY (feature);
163 /* this isn't an error, for instance when you query if an element factory is
165 GST_LOG ("no such element factory \"%s\"", name);
170 __gst_element_details_clear (GstElementDetails * dp)
172 g_free (dp->longname);
174 g_free (dp->description);
176 memset (dp, 0, sizeof (GstElementDetails));
179 #define VALIDATE_SET(__dest, __src, __entry) \
181 if (g_utf8_validate (__src->__entry, -1, NULL)) { \
182 __dest->__entry = g_strdup (__src->__entry); \
184 g_warning ("Invalid UTF-8 in " G_STRINGIFY (__entry) ": %s", \
186 __dest->__entry = g_strdup ("[ERROR: invalid UTF-8]"); \
191 __gst_element_details_set (GstElementDetails * dest,
192 const GstElementDetails * src)
194 VALIDATE_SET (dest, src, longname);
195 VALIDATE_SET (dest, src, klass);
196 VALIDATE_SET (dest, src, description);
197 VALIDATE_SET (dest, src, author);
201 __gst_element_details_copy (GstElementDetails * dest,
202 const GstElementDetails * src)
204 __gst_element_details_clear (dest);
205 __gst_element_details_set (dest, src);
209 gst_element_factory_cleanup (GstElementFactory * factory)
213 __gst_element_details_clear (&factory->details);
215 g_type_class_unref (g_type_class_peek (factory->type));
219 for (item = factory->staticpadtemplates; item; item = item->next) {
220 GstStaticPadTemplate *templ = item->data;
221 GstCaps *caps = (GstCaps *) & (templ->static_caps);
223 g_free ((gchar *) templ->static_caps.string);
225 /* FIXME: this is not threadsafe */
226 if (caps->refcount == 1) {
227 GstStructure *structure;
230 for (i = 0; i < caps->structs->len; i++) {
231 structure = (GstStructure *) gst_caps_get_structure (caps, i);
232 gst_structure_set_parent_refcount (structure, NULL);
233 gst_structure_free (structure);
235 g_ptr_array_free (caps->structs, TRUE);
240 g_list_free (factory->staticpadtemplates);
241 factory->staticpadtemplates = NULL;
242 factory->numpadtemplates = 0;
243 factory->uri_type = GST_URI_UNKNOWN;
244 if (factory->uri_protocols) {
245 g_strfreev (factory->uri_protocols);
246 factory->uri_protocols = NULL;
249 g_list_foreach (factory->interfaces, (GFunc) g_free, NULL);
250 g_list_free (factory->interfaces);
251 factory->interfaces = NULL;
255 * gst_element_register:
256 * @plugin: #GstPlugin to register the element with, or NULL for a static
257 * element (note that passing NULL only works in GStreamer 0.10.13 and later)
258 * @name: name of elements of this type
259 * @rank: rank of element (higher rank means more importance when autoplugging)
260 * @type: GType of element to register
262 * Create a new elementfactory capable of instantiating objects of the
263 * @type and add the factory to @plugin.
265 * Returns: TRUE, if the registering succeeded, FALSE on error
268 gst_element_register (GstPlugin * plugin, const gchar * name, guint rank,
271 GstElementFactory *factory;
273 guint n_interfaces, i;
274 GstElementClass *klass;
277 g_return_val_if_fail (name != NULL, FALSE);
278 g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
280 factory = GST_ELEMENT_FACTORY (g_object_new (GST_TYPE_ELEMENT_FACTORY, NULL));
281 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE (factory), name);
282 GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
285 klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
286 if ((klass->details.longname == NULL) ||
287 (klass->details.klass == NULL) || (klass->details.author == NULL))
290 factory->type = type;
291 __gst_element_details_copy (&factory->details, &klass->details);
292 for (item = klass->padtemplates; item; item = item->next) {
293 GstPadTemplate *templ = item->data;
294 GstStaticPadTemplate *newt;
296 newt = g_new0 (GstStaticPadTemplate, 1);
297 newt->name_template = g_intern_string (templ->name_template);
298 newt->direction = templ->direction;
299 newt->presence = templ->presence;
300 newt->static_caps.string = gst_caps_to_string (templ->caps);
301 factory->staticpadtemplates =
302 g_list_append (factory->staticpadtemplates, newt);
304 factory->numpadtemplates = klass->numpadtemplates;
305 klass->elementfactory = factory;
307 /* special stuff for URI handling */
308 if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
309 GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
310 g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
312 if (!iface || (!iface->get_type && !iface->get_type_full) ||
313 (!iface->get_protocols && !iface->get_protocols_full))
316 factory->uri_type = iface->get_type ();
317 else if (iface->get_type_full)
318 factory->uri_type = iface->get_type_full (factory->type);
319 if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
321 if (iface->get_protocols)
322 factory->uri_protocols = g_strdupv (iface->get_protocols ());
323 else if (iface->get_protocols_full)
324 factory->uri_protocols = iface->get_protocols_full (factory->type);
325 if (!factory->uri_protocols)
329 interfaces = g_type_interfaces (type, &n_interfaces);
330 for (i = 0; i < n_interfaces; i++) {
331 __gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
335 if (plugin && plugin->desc.name) {
336 GST_PLUGIN_FEATURE (factory)->plugin_name = plugin->desc.name;
338 GST_PLUGIN_FEATURE (factory)->plugin_name = "NULL";
340 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE (factory), rank);
341 GST_PLUGIN_FEATURE (factory)->loaded = TRUE;
343 gst_registry_add_feature (gst_registry_get_default (),
344 GST_PLUGIN_FEATURE (factory));
351 GST_WARNING_OBJECT (factory, "error with uri handler!");
352 gst_element_factory_cleanup (factory);
358 GST_WARNING_OBJECT (factory,
359 "The GstElementDetails don't seem to have been set properly");
360 gst_element_factory_cleanup (factory);
366 * gst_element_factory_create:
367 * @factory: factory to instantiate
368 * @name: name of new element
370 * Create a new element of the type defined by the given elementfactory.
371 * It will be given the name supplied, since all elements require a name as
372 * their first argument.
374 * Returns: new #GstElement or NULL if the element couldn't be created
377 gst_element_factory_create (GstElementFactory * factory, const gchar * name)
380 GstElementClass *oclass;
381 GstElementFactory *newfactory;
383 g_return_val_if_fail (factory != NULL, NULL);
386 GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
389 if (newfactory == NULL)
392 factory = newfactory;
395 GST_INFO ("creating element \"%s\" named \"%s\"",
396 GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
398 GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
400 if (factory->type == 0)
403 /* create an instance of the element, cast so we don't assert on NULL */
404 element = GST_ELEMENT_CAST (g_object_new (factory->type, NULL));
405 if (G_UNLIKELY (element == NULL))
408 /* fill in the pointer to the factory in the element class. The
409 * class will not be unreffed currently.
410 * FIXME: This isn't safe and may leak a refcount on the factory if 2 threads
411 * create the first instance of an element at the same moment */
412 oclass = GST_ELEMENT_GET_CLASS (element);
413 if (G_UNLIKELY (oclass->elementfactory == NULL))
414 oclass->elementfactory = factory;
416 gst_object_unref (factory);
419 gst_object_set_name (GST_OBJECT (element), name);
421 GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
428 GST_WARNING_OBJECT (factory, "loading plugin returned NULL!");
433 GST_WARNING_OBJECT (factory, "factory has no type");
434 gst_object_unref (factory);
439 GST_WARNING_OBJECT (factory, "could not create element");
440 gst_object_unref (factory);
446 * gst_element_factory_make:
447 * @factoryname: a named factory to instantiate
448 * @name: name of new element
450 * Create a new element of the type defined by the given element factory.
451 * If name is NULL, then the element will receive a guaranteed unique name,
452 * consisting of the element factory name and a number.
453 * If name is given, it will be given the name supplied.
455 * Returns: new #GstElement or NULL if unable to create element
458 gst_element_factory_make (const gchar * factoryname, const gchar * name)
460 GstElementFactory *factory;
463 g_return_val_if_fail (factoryname != NULL, NULL);
465 GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
466 factoryname, GST_STR_NULL (name));
468 factory = gst_element_factory_find (factoryname);
472 GST_LOG_OBJECT (factory, "found factory %p", factory);
473 element = gst_element_factory_create (factory, name);
477 gst_object_unref (factory);
483 GST_INFO ("no such element factory \"%s\"!", factoryname);
488 GST_INFO_OBJECT (factory, "couldn't create instance!");
489 gst_object_unref (factory);
495 __gst_element_factory_add_static_pad_template (GstElementFactory * factory,
496 GstStaticPadTemplate * templ)
498 g_return_if_fail (factory != NULL);
499 g_return_if_fail (templ != NULL);
501 factory->staticpadtemplates =
502 g_list_append (factory->staticpadtemplates, templ);
503 factory->numpadtemplates++;
507 * gst_element_factory_get_element_type:
508 * @factory: factory to get managed #GType from
510 * Get the #GType for elements managed by this factory. The type can
511 * only be retrieved if the element factory is loaded, which can be
512 * assured with gst_plugin_feature_load().
514 * Returns: the #GType for elements managed by this factory or 0 if
515 * the factory is not loaded.
518 gst_element_factory_get_element_type (GstElementFactory * factory)
520 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
522 return factory->type;
526 * gst_element_factory_get_longname:
527 * @factory: a #GstElementFactory
529 * Gets the longname for this factory
531 * Returns: the longname
533 G_CONST_RETURN gchar *
534 gst_element_factory_get_longname (GstElementFactory * factory)
536 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
538 return factory->details.longname;
542 * gst_element_factory_get_klass:
543 * @factory: a #GstElementFactory
545 * Gets the class for this factory.
549 G_CONST_RETURN gchar *
550 gst_element_factory_get_klass (GstElementFactory * factory)
552 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
554 return factory->details.klass;
558 * gst_element_factory_get_description:
559 * @factory: a #GstElementFactory
561 * Gets the description for this factory.
563 * Returns: the description
565 G_CONST_RETURN gchar *
566 gst_element_factory_get_description (GstElementFactory * factory)
568 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
570 return factory->details.description;
574 * gst_element_factory_get_author:
575 * @factory: a #GstElementFactory
577 * Gets the author for this factory.
579 * Returns: the author
581 G_CONST_RETURN gchar *
582 gst_element_factory_get_author (GstElementFactory * factory)
584 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
586 return factory->details.author;
590 * gst_element_factory_get_num_pad_templates:
591 * @factory: a #GstElementFactory
593 * Gets the number of pad_templates in this factory.
595 * Returns: the number of pad_templates
598 gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
600 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
602 return factory->numpadtemplates;
606 * __gst_element_factory_add_interface:
607 * @elementfactory: The elementfactory to add the interface to
608 * @interfacename: Name of the interface
610 * Adds the given interfacename to the list of implemented interfaces of the
614 __gst_element_factory_add_interface (GstElementFactory * elementfactory,
615 const gchar * interfacename)
617 g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
618 g_return_if_fail (interfacename != NULL);
619 g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
621 elementfactory->interfaces =
622 g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
626 * gst_element_factory_get_static_pad_templates:
627 * @factory: a #GstElementFactory
629 * Gets the #GList of #GstStaticPadTemplate for this factory.
631 * Returns: the padtemplates
633 G_CONST_RETURN GList *
634 gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
636 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
638 return factory->staticpadtemplates;
642 * gst_element_factory_get_uri_type:
643 * @factory: a #GstElementFactory
645 * Gets the type of URIs the element supports or #GST_URI_UNKNOWN if none.
647 * Returns: type of URIs this element supports
650 gst_element_factory_get_uri_type (GstElementFactory * factory)
652 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
654 return factory->uri_type;
658 * gst_element_factory_get_uri_protocols:
659 * @factory: a #GstElementFactory
661 * Gets a NULL-terminated array of protocols this element supports or NULL if
662 * no protocols are supported. You may not change the contents of the returned
663 * array, as it is still owned by the element factory. Use g_strdupv() to
664 * make a copy of the protocol string array if you need to.
666 * Returns: the supported protocols or NULL
669 gst_element_factory_get_uri_protocols (GstElementFactory * factory)
671 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
673 return factory->uri_protocols;
677 * gst_element_factory_has_interface:
678 * @factory: a #GstElementFactory
679 * @interfacename: an interface name
681 * Check if @factory implements the interface with name @interfacename.
683 * Returns: #TRUE when @factory implement the interface.
688 gst_element_factory_has_interface (GstElementFactory * factory,
689 const gchar * interfacename)
693 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
695 for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
696 gchar *iname = (gchar *) walk->data;
698 if (!strcmp (iname, interfacename))