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 }; */
82 /* this is defined in gstelement.c */
83 extern GQuark _gst_elementclass_factory;
87 GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY", \
88 GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, \
89 "element factories keep information about installed elements"); \
92 G_DEFINE_TYPE_WITH_CODE (GstElementFactory, gst_element_factory,
93 GST_TYPE_PLUGIN_FEATURE, _do_init);
96 gst_element_factory_class_init (GstElementFactoryClass * klass)
98 GObjectClass *gobject_class = (GObjectClass *) klass;
100 parent_class = g_type_class_peek_parent (klass);
102 gobject_class->finalize = gst_element_factory_finalize;
106 gst_element_factory_init (GstElementFactory * factory)
108 factory->staticpadtemplates = NULL;
109 factory->numpadtemplates = 0;
111 factory->uri_type = GST_URI_UNKNOWN;
112 factory->uri_protocols = NULL;
114 factory->interfaces = NULL;
118 gst_element_factory_finalize (GObject * object)
120 GstElementFactory *factory = GST_ELEMENT_FACTORY (object);
122 gst_element_factory_cleanup (factory);
123 G_OBJECT_CLASS (parent_class)->finalize (object);
127 * gst_element_factory_find:
128 * @name: name of factory to find
130 * Search for an element factory of the given name. Refs the returned
131 * element factory; caller is responsible for unreffing.
133 * Returns: #GstElementFactory if found, NULL otherwise
136 gst_element_factory_find (const gchar * name)
138 GstPluginFeature *feature;
140 g_return_val_if_fail (name != NULL, NULL);
142 feature = gst_registry_find_feature (gst_registry_get_default (), name,
143 GST_TYPE_ELEMENT_FACTORY);
145 return GST_ELEMENT_FACTORY (feature);
147 /* this isn't an error, for instance when you query if an element factory is
149 GST_LOG ("no such element factory \"%s\"", name);
154 __gst_element_details_clear (GstElementDetails * dp)
156 g_free (dp->longname);
158 g_free (dp->description);
160 memset (dp, 0, sizeof (GstElementDetails));
163 #define VALIDATE_SET(__dest, __src, __entry) \
165 if (g_utf8_validate (__src->__entry, -1, NULL)) { \
166 __dest->__entry = g_strdup (__src->__entry); \
168 g_warning ("Invalid UTF-8 in " G_STRINGIFY (__entry) ": %s", \
170 __dest->__entry = g_strdup ("[ERROR: invalid UTF-8]"); \
175 __gst_element_details_set (GstElementDetails * dest,
176 const GstElementDetails * src)
178 VALIDATE_SET (dest, src, longname);
179 VALIDATE_SET (dest, src, klass);
180 VALIDATE_SET (dest, src, description);
181 VALIDATE_SET (dest, src, author);
185 __gst_element_details_copy (GstElementDetails * dest,
186 const GstElementDetails * src)
188 __gst_element_details_clear (dest);
189 __gst_element_details_set (dest, src);
193 gst_element_factory_cleanup (GstElementFactory * factory)
197 __gst_element_details_clear (&factory->details);
199 factory->type = G_TYPE_INVALID;
202 for (item = factory->staticpadtemplates; item; item = item->next) {
203 GstStaticPadTemplate *templ = item->data;
204 GstCaps *caps = (GstCaps *) & (templ->static_caps);
206 g_free ((gchar *) templ->static_caps.string);
208 /* FIXME: this is not threadsafe */
209 if (caps->refcount == 1) {
210 GstStructure *structure;
213 for (i = 0; i < caps->structs->len; i++) {
214 structure = (GstStructure *) gst_caps_get_structure (caps, i);
215 gst_structure_set_parent_refcount (structure, NULL);
216 gst_structure_free (structure);
218 g_ptr_array_free (caps->structs, TRUE);
223 g_list_free (factory->staticpadtemplates);
224 factory->staticpadtemplates = NULL;
225 factory->numpadtemplates = 0;
226 factory->uri_type = GST_URI_UNKNOWN;
227 if (factory->uri_protocols) {
228 g_strfreev (factory->uri_protocols);
229 factory->uri_protocols = NULL;
232 g_list_foreach (factory->interfaces, (GFunc) g_free, NULL);
233 g_list_free (factory->interfaces);
234 factory->interfaces = NULL;
238 * gst_element_register:
239 * @plugin: #GstPlugin to register the element with, or NULL for a static
240 * element (note that passing NULL only works in GStreamer 0.10.13 and later)
241 * @name: name of elements of this type
242 * @rank: rank of element (higher rank means more importance when autoplugging)
243 * @type: GType of element to register
245 * Create a new elementfactory capable of instantiating objects of the
246 * @type and add the factory to @plugin.
248 * Returns: TRUE, if the registering succeeded, FALSE on error
251 gst_element_register (GstPlugin * plugin, const gchar * name, guint rank,
254 GstPluginFeature *existing_feature;
255 GstRegistry *registry;
256 GstElementFactory *factory;
258 guint n_interfaces, i;
259 GstElementClass *klass;
262 g_return_val_if_fail (name != NULL, FALSE);
263 g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
265 registry = gst_registry_get_default ();
267 /* check if feature already exists, if it exists there is no need to update it
268 * when the registry is getting updated, outdated plugins and all their
269 * features are removed and readded.
271 existing_feature = gst_registry_lookup_feature (registry, name);
272 if (existing_feature) {
273 GST_DEBUG_OBJECT (registry, "update existing feature %p (%s)",
274 existing_feature, name);
275 factory = GST_ELEMENT_FACTORY_CAST (existing_feature);
276 factory->type = type;
277 existing_feature->loaded = TRUE;
278 g_type_set_qdata (type, _gst_elementclass_factory, factory);
279 gst_object_unref (existing_feature);
284 GST_ELEMENT_FACTORY_CAST (g_object_newv (GST_TYPE_ELEMENT_FACTORY, 0,
286 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
287 GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
290 /* provide info needed during class structure setup */
291 g_type_set_qdata (type, _gst_elementclass_factory, factory);
292 klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
293 if ((klass->details.longname == NULL) ||
294 (klass->details.klass == NULL) || (klass->details.author == NULL))
297 factory->type = type;
298 __gst_element_details_copy (&factory->details, &klass->details);
299 for (item = klass->padtemplates; item; item = item->next) {
300 GstPadTemplate *templ = item->data;
301 GstStaticPadTemplate *newt;
303 newt = g_new0 (GstStaticPadTemplate, 1);
304 newt->name_template = g_intern_string (templ->name_template);
305 newt->direction = templ->direction;
306 newt->presence = templ->presence;
307 newt->static_caps.string = gst_caps_to_string (templ->caps);
308 factory->staticpadtemplates =
309 g_list_append (factory->staticpadtemplates, newt);
311 factory->numpadtemplates = klass->numpadtemplates;
313 /* special stuff for URI handling */
314 if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
315 GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
316 g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
318 if (!iface || (!iface->get_type && !iface->get_type_full) ||
319 (!iface->get_protocols && !iface->get_protocols_full))
322 factory->uri_type = iface->get_type ();
323 else if (iface->get_type_full)
324 factory->uri_type = iface->get_type_full (factory->type);
325 if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
327 if (iface->get_protocols)
328 factory->uri_protocols = g_strdupv (iface->get_protocols ());
329 else if (iface->get_protocols_full)
330 factory->uri_protocols = iface->get_protocols_full (factory->type);
331 if (!factory->uri_protocols)
335 interfaces = g_type_interfaces (type, &n_interfaces);
336 for (i = 0; i < n_interfaces; i++) {
337 __gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
341 if (plugin && plugin->desc.name) {
342 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name;
344 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
346 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);
347 GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;
349 gst_registry_add_feature (registry, GST_PLUGIN_FEATURE_CAST (factory));
356 GST_WARNING_OBJECT (factory, "error with uri handler!");
357 gst_element_factory_cleanup (factory);
363 GST_WARNING_OBJECT (factory,
364 "The GstElementDetails don't seem to have been set properly");
365 gst_element_factory_cleanup (factory);
371 * gst_element_factory_create:
372 * @factory: factory to instantiate
373 * @name: name of new element
375 * Create a new element of the type defined by the given elementfactory.
376 * It will be given the name supplied, since all elements require a name as
377 * their first argument.
379 * Returns: new #GstElement or NULL if the element couldn't be created
382 gst_element_factory_create (GstElementFactory * factory, const gchar * name)
385 GstElementClass *oclass;
386 GstElementFactory *newfactory;
388 g_return_val_if_fail (factory != NULL, NULL);
391 GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
394 if (newfactory == NULL)
397 factory = newfactory;
400 GST_INFO ("creating element \"%s\" named \"%s\"",
401 GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
403 GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
405 if (factory->type == 0)
408 /* create an instance of the element, cast so we don't assert on NULL
409 * also set name as early as we can
413 GST_ELEMENT_CAST (g_object_new (factory->type, "name", name, NULL));
415 element = GST_ELEMENT_CAST (g_object_newv (factory->type, 0, NULL));
416 if (G_UNLIKELY (element == NULL))
419 /* fill in the pointer to the factory in the element class. The
420 * class will not be unreffed currently.
421 * Be thread safe as there might be 2 threads creating the first instance of
422 * an element at the same moment
424 oclass = GST_ELEMENT_GET_CLASS (element);
425 if (!g_atomic_pointer_compare_and_exchange (
426 (gpointer) & oclass->elementfactory, NULL, factory))
427 gst_object_unref (factory);
429 GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
436 GST_WARNING_OBJECT (factory,
437 "loading plugin containing feature %s returned NULL!", name);
442 GST_WARNING_OBJECT (factory, "factory has no type");
443 gst_object_unref (factory);
448 GST_WARNING_OBJECT (factory, "could not create element");
449 gst_object_unref (factory);
455 * gst_element_factory_make:
456 * @factoryname: a named factory to instantiate
457 * @name: name of new element
459 * Create a new element of the type defined by the given element factory.
460 * If name is NULL, then the element will receive a guaranteed unique name,
461 * consisting of the element factory name and a number.
462 * If name is given, it will be given the name supplied.
464 * Returns: new #GstElement or NULL if unable to create element
467 gst_element_factory_make (const gchar * factoryname, const gchar * name)
469 GstElementFactory *factory;
472 g_return_val_if_fail (factoryname != NULL, NULL);
474 GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
475 factoryname, GST_STR_NULL (name));
477 factory = gst_element_factory_find (factoryname);
481 GST_LOG_OBJECT (factory, "found factory %p", factory);
482 element = gst_element_factory_create (factory, name);
486 gst_object_unref (factory);
492 GST_INFO ("no such element factory \"%s\"!", factoryname);
497 GST_INFO_OBJECT (factory, "couldn't create instance!");
498 gst_object_unref (factory);
504 __gst_element_factory_add_static_pad_template (GstElementFactory * factory,
505 GstStaticPadTemplate * templ)
507 g_return_if_fail (factory != NULL);
508 g_return_if_fail (templ != NULL);
510 factory->staticpadtemplates =
511 g_list_append (factory->staticpadtemplates, templ);
512 factory->numpadtemplates++;
516 * gst_element_factory_get_element_type:
517 * @factory: factory to get managed #GType from
519 * Get the #GType for elements managed by this factory. The type can
520 * only be retrieved if the element factory is loaded, which can be
521 * assured with gst_plugin_feature_load().
523 * Returns: the #GType for elements managed by this factory or 0 if
524 * the factory is not loaded.
527 gst_element_factory_get_element_type (GstElementFactory * factory)
529 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
531 return factory->type;
535 * gst_element_factory_get_longname:
536 * @factory: a #GstElementFactory
538 * Gets the longname for this factory
540 * Returns: the longname
542 G_CONST_RETURN gchar *
543 gst_element_factory_get_longname (GstElementFactory * factory)
545 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
547 return factory->details.longname;
551 * gst_element_factory_get_klass:
552 * @factory: a #GstElementFactory
554 * Gets the class for this factory.
558 G_CONST_RETURN gchar *
559 gst_element_factory_get_klass (GstElementFactory * factory)
561 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
563 return factory->details.klass;
567 * gst_element_factory_get_description:
568 * @factory: a #GstElementFactory
570 * Gets the description for this factory.
572 * Returns: the description
574 G_CONST_RETURN gchar *
575 gst_element_factory_get_description (GstElementFactory * factory)
577 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
579 return factory->details.description;
583 * gst_element_factory_get_author:
584 * @factory: a #GstElementFactory
586 * Gets the author for this factory.
588 * Returns: the author
590 G_CONST_RETURN gchar *
591 gst_element_factory_get_author (GstElementFactory * factory)
593 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
595 return factory->details.author;
599 * gst_element_factory_get_num_pad_templates:
600 * @factory: a #GstElementFactory
602 * Gets the number of pad_templates in this factory.
604 * Returns: the number of pad_templates
607 gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
609 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
611 return factory->numpadtemplates;
615 * __gst_element_factory_add_interface:
616 * @elementfactory: The elementfactory to add the interface to
617 * @interfacename: Name of the interface
619 * Adds the given interfacename to the list of implemented interfaces of the
623 __gst_element_factory_add_interface (GstElementFactory * elementfactory,
624 const gchar * interfacename)
626 g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
627 g_return_if_fail (interfacename != NULL);
628 g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
630 elementfactory->interfaces =
631 g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
635 * gst_element_factory_get_static_pad_templates:
636 * @factory: a #GstElementFactory
638 * Gets the #GList of #GstStaticPadTemplate for this factory.
640 * Returns: the padtemplates
642 G_CONST_RETURN GList *
643 gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
645 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
647 return factory->staticpadtemplates;
651 * gst_element_factory_get_uri_type:
652 * @factory: a #GstElementFactory
654 * Gets the type of URIs the element supports or #GST_URI_UNKNOWN if none.
656 * Returns: type of URIs this element supports
659 gst_element_factory_get_uri_type (GstElementFactory * factory)
661 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
663 return factory->uri_type;
667 * gst_element_factory_get_uri_protocols:
668 * @factory: a #GstElementFactory
670 * Gets a NULL-terminated array of protocols this element supports or NULL if
671 * no protocols are supported. You may not change the contents of the returned
672 * array, as it is still owned by the element factory. Use g_strdupv() to
673 * make a copy of the protocol string array if you need to.
675 * Returns: the supported protocols or NULL
678 gst_element_factory_get_uri_protocols (GstElementFactory * factory)
680 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
682 return factory->uri_protocols;
686 * gst_element_factory_has_interface:
687 * @factory: a #GstElementFactory
688 * @interfacename: an interface name
690 * Check if @factory implements the interface with name @interfacename.
692 * Returns: #TRUE when @factory implement the interface.
697 gst_element_factory_has_interface (GstElementFactory * factory,
698 const gchar * interfacename)
702 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
704 for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
705 gchar *iname = (gchar *) walk->data;
707 if (!strcmp (iname, interfacename))