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_finalize (GObject * object);
73 void __gst_element_details_clear (GstElementDetails * dp);
74 static void gst_element_factory_cleanup (GstElementFactory * factory);
76 static GstPluginFeatureClass *parent_class = NULL;
78 /* static guint gst_element_factory_signals[LAST_SIGNAL] = { 0 }; */
80 /* this is defined in gstelement.c */
81 extern GQuark _gst_elementclass_factory;
85 GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY", \
86 GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, \
87 "element factories keep information about installed elements"); \
90 G_DEFINE_TYPE_WITH_CODE (GstElementFactory, gst_element_factory,
91 GST_TYPE_PLUGIN_FEATURE, _do_init);
94 gst_element_factory_class_init (GstElementFactoryClass * klass)
96 GObjectClass *gobject_class = (GObjectClass *) klass;
98 parent_class = g_type_class_peek_parent (klass);
100 gobject_class->finalize = gst_element_factory_finalize;
104 gst_element_factory_init (GstElementFactory * factory)
106 factory->staticpadtemplates = NULL;
107 factory->numpadtemplates = 0;
109 factory->uri_type = GST_URI_UNKNOWN;
110 factory->uri_protocols = NULL;
112 factory->interfaces = NULL;
116 gst_element_factory_finalize (GObject * object)
118 GstElementFactory *factory = GST_ELEMENT_FACTORY (object);
120 gst_element_factory_cleanup (factory);
121 G_OBJECT_CLASS (parent_class)->finalize (object);
125 * gst_element_factory_find:
126 * @name: name of factory to find
128 * Search for an element factory of the given name. Refs the returned
129 * element factory; caller is responsible for unreffing.
131 * Returns: #GstElementFactory if found, NULL otherwise
134 gst_element_factory_find (const gchar * name)
136 GstPluginFeature *feature;
138 g_return_val_if_fail (name != NULL, NULL);
140 feature = gst_registry_find_feature (gst_registry_get_default (), name,
141 GST_TYPE_ELEMENT_FACTORY);
143 return GST_ELEMENT_FACTORY (feature);
145 /* this isn't an error, for instance when you query if an element factory is
147 GST_LOG ("no such element factory \"%s\"", name);
152 __gst_element_details_clear (GstElementDetails * dp)
154 g_free (dp->longname);
156 g_free (dp->description);
158 memset (dp, 0, sizeof (GstElementDetails));
161 #define VALIDATE_SET(__dest, __src, __entry) \
163 if (g_utf8_validate (__src->__entry, -1, NULL)) { \
164 __dest->__entry = g_strdup (__src->__entry); \
166 g_warning ("Invalid UTF-8 in " G_STRINGIFY (__entry) ": %s", \
168 __dest->__entry = g_strdup ("[ERROR: invalid UTF-8]"); \
173 __gst_element_details_set (GstElementDetails * dest,
174 const GstElementDetails * src)
176 VALIDATE_SET (dest, src, longname);
177 VALIDATE_SET (dest, src, klass);
178 VALIDATE_SET (dest, src, description);
179 VALIDATE_SET (dest, src, author);
183 __gst_element_details_copy (GstElementDetails * dest,
184 const GstElementDetails * src)
186 __gst_element_details_clear (dest);
187 __gst_element_details_set (dest, src);
191 gst_element_factory_cleanup (GstElementFactory * factory)
195 __gst_element_details_clear (&factory->details);
197 factory->type = G_TYPE_INVALID;
200 for (item = factory->staticpadtemplates; item; item = item->next) {
201 GstStaticPadTemplate *templ = item->data;
202 GstCaps *caps = (GstCaps *) & (templ->static_caps);
204 g_free ((gchar *) templ->static_caps.string);
206 /* FIXME: this is not threadsafe */
207 if (caps->refcount == 1) {
208 GstStructure *structure;
211 for (i = 0; i < caps->structs->len; i++) {
212 structure = (GstStructure *) gst_caps_get_structure (caps, i);
213 gst_structure_set_parent_refcount (structure, NULL);
214 gst_structure_free (structure);
216 g_ptr_array_free (caps->structs, TRUE);
221 g_list_free (factory->staticpadtemplates);
222 factory->staticpadtemplates = NULL;
223 factory->numpadtemplates = 0;
224 factory->uri_type = GST_URI_UNKNOWN;
225 if (factory->uri_protocols) {
226 g_strfreev (factory->uri_protocols);
227 factory->uri_protocols = NULL;
230 g_list_foreach (factory->interfaces, (GFunc) g_free, NULL);
231 g_list_free (factory->interfaces);
232 factory->interfaces = NULL;
236 * gst_element_register:
237 * @plugin: #GstPlugin to register the element with, or NULL for a static
238 * element (note that passing NULL only works in GStreamer 0.10.13 and later)
239 * @name: name of elements of this type
240 * @rank: rank of element (higher rank means more importance when autoplugging)
241 * @type: GType of element to register
243 * Create a new elementfactory capable of instantiating objects of the
244 * @type and add the factory to @plugin.
246 * Returns: TRUE, if the registering succeeded, FALSE on error
249 gst_element_register (GstPlugin * plugin, const gchar * name, guint rank,
252 GstPluginFeature *existing_feature;
253 GstRegistry *registry;
254 GstElementFactory *factory;
256 guint n_interfaces, i;
257 GstElementClass *klass;
260 g_return_val_if_fail (name != NULL, FALSE);
261 g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
263 registry = gst_registry_get_default ();
265 /* check if feature already exists, if it exists there is no need to update it
266 * when the registry is getting updated, outdated plugins and all their
267 * features are removed and readded.
269 existing_feature = gst_registry_lookup_feature (registry, name);
270 if (existing_feature) {
271 GST_DEBUG_OBJECT (registry, "update existing feature %p (%s)",
272 existing_feature, name);
273 factory = GST_ELEMENT_FACTORY_CAST (existing_feature);
274 factory->type = type;
275 existing_feature->loaded = TRUE;
276 g_type_set_qdata (type, _gst_elementclass_factory, factory);
277 gst_object_unref (existing_feature);
282 GST_ELEMENT_FACTORY_CAST (g_object_newv (GST_TYPE_ELEMENT_FACTORY, 0,
284 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
285 GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
288 /* provide info needed during class structure setup */
289 g_type_set_qdata (type, _gst_elementclass_factory, factory);
290 klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
291 if ((klass->details.longname == NULL) ||
292 (klass->details.klass == NULL) || (klass->details.author == NULL))
295 factory->type = type;
296 __gst_element_details_copy (&factory->details, &klass->details);
297 for (item = klass->padtemplates; item; item = item->next) {
298 GstPadTemplate *templ = item->data;
299 GstStaticPadTemplate *newt;
301 newt = g_new0 (GstStaticPadTemplate, 1);
302 newt->name_template = g_intern_string (templ->name_template);
303 newt->direction = templ->direction;
304 newt->presence = templ->presence;
305 newt->static_caps.string = gst_caps_to_string (templ->caps);
306 factory->staticpadtemplates =
307 g_list_append (factory->staticpadtemplates, newt);
309 factory->numpadtemplates = klass->numpadtemplates;
311 /* special stuff for URI handling */
312 if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
313 GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
314 g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
316 if (!iface || (!iface->get_type && !iface->get_type_full) ||
317 (!iface->get_protocols && !iface->get_protocols_full))
320 factory->uri_type = iface->get_type ();
321 else if (iface->get_type_full)
322 factory->uri_type = iface->get_type_full (factory->type);
323 if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
325 if (iface->get_protocols)
326 factory->uri_protocols = g_strdupv (iface->get_protocols ());
327 else if (iface->get_protocols_full)
328 factory->uri_protocols = iface->get_protocols_full (factory->type);
329 if (!factory->uri_protocols)
333 interfaces = g_type_interfaces (type, &n_interfaces);
334 for (i = 0; i < n_interfaces; i++) {
335 __gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
339 if (plugin && plugin->desc.name) {
340 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name;
342 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
344 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);
345 GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;
347 gst_registry_add_feature (registry, GST_PLUGIN_FEATURE_CAST (factory));
354 GST_WARNING_OBJECT (factory, "error with uri handler!");
355 gst_element_factory_cleanup (factory);
361 GST_WARNING_OBJECT (factory,
362 "The GstElementDetails don't seem to have been set properly");
363 gst_element_factory_cleanup (factory);
369 * gst_element_factory_create:
370 * @factory: factory to instantiate
371 * @name: name of new element
373 * Create a new element of the type defined by the given elementfactory.
374 * It will be given the name supplied, since all elements require a name as
375 * their first argument.
377 * Returns: new #GstElement or NULL if the element couldn't be created
380 gst_element_factory_create (GstElementFactory * factory, const gchar * name)
383 GstElementClass *oclass;
384 GstElementFactory *newfactory;
386 g_return_val_if_fail (factory != NULL, NULL);
389 GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
392 if (newfactory == NULL)
395 factory = newfactory;
398 GST_INFO ("creating element \"%s\" named \"%s\"",
399 GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
401 GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
403 if (factory->type == 0)
406 /* create an instance of the element, cast so we don't assert on NULL
407 * also set name as early as we can
411 GST_ELEMENT_CAST (g_object_new (factory->type, "name", name, NULL));
413 element = GST_ELEMENT_CAST (g_object_newv (factory->type, 0, NULL));
414 if (G_UNLIKELY (element == NULL))
417 /* fill in the pointer to the factory in the element class. The
418 * class will not be unreffed currently.
419 * Be thread safe as there might be 2 threads creating the first instance of
420 * an element at the same moment
422 oclass = GST_ELEMENT_GET_CLASS (element);
423 if (!g_atomic_pointer_compare_and_exchange (
424 (gpointer) & oclass->elementfactory, NULL, factory))
425 gst_object_unref (factory);
427 GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
434 GST_WARNING_OBJECT (factory,
435 "loading plugin containing feature %s returned NULL!", name);
440 GST_WARNING_OBJECT (factory, "factory has no type");
441 gst_object_unref (factory);
446 GST_WARNING_OBJECT (factory, "could not create element");
447 gst_object_unref (factory);
453 * gst_element_factory_make:
454 * @factoryname: a named factory to instantiate
455 * @name: name of new element
457 * Create a new element of the type defined by the given element factory.
458 * If name is NULL, then the element will receive a guaranteed unique name,
459 * consisting of the element factory name and a number.
460 * If name is given, it will be given the name supplied.
462 * Returns: new #GstElement or NULL if unable to create element
465 gst_element_factory_make (const gchar * factoryname, const gchar * name)
467 GstElementFactory *factory;
470 g_return_val_if_fail (factoryname != NULL, NULL);
472 GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
473 factoryname, GST_STR_NULL (name));
475 factory = gst_element_factory_find (factoryname);
479 GST_LOG_OBJECT (factory, "found factory %p", factory);
480 element = gst_element_factory_create (factory, name);
484 gst_object_unref (factory);
490 GST_INFO ("no such element factory \"%s\"!", factoryname);
495 GST_INFO_OBJECT (factory, "couldn't create instance!");
496 gst_object_unref (factory);
502 __gst_element_factory_add_static_pad_template (GstElementFactory * factory,
503 GstStaticPadTemplate * templ)
505 g_return_if_fail (factory != NULL);
506 g_return_if_fail (templ != NULL);
508 factory->staticpadtemplates =
509 g_list_append (factory->staticpadtemplates, templ);
510 factory->numpadtemplates++;
514 * gst_element_factory_get_element_type:
515 * @factory: factory to get managed #GType from
517 * Get the #GType for elements managed by this factory. The type can
518 * only be retrieved if the element factory is loaded, which can be
519 * assured with gst_plugin_feature_load().
521 * Returns: the #GType for elements managed by this factory or 0 if
522 * the factory is not loaded.
525 gst_element_factory_get_element_type (GstElementFactory * factory)
527 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
529 return factory->type;
533 * gst_element_factory_get_longname:
534 * @factory: a #GstElementFactory
536 * Gets the longname for this factory
538 * Returns: the longname
540 G_CONST_RETURN gchar *
541 gst_element_factory_get_longname (GstElementFactory * factory)
543 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
545 return factory->details.longname;
549 * gst_element_factory_get_klass:
550 * @factory: a #GstElementFactory
552 * Gets the class for this factory.
556 G_CONST_RETURN gchar *
557 gst_element_factory_get_klass (GstElementFactory * factory)
559 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
561 return factory->details.klass;
565 * gst_element_factory_get_description:
566 * @factory: a #GstElementFactory
568 * Gets the description for this factory.
570 * Returns: the description
572 G_CONST_RETURN gchar *
573 gst_element_factory_get_description (GstElementFactory * factory)
575 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
577 return factory->details.description;
581 * gst_element_factory_get_author:
582 * @factory: a #GstElementFactory
584 * Gets the author for this factory.
586 * Returns: the author
588 G_CONST_RETURN gchar *
589 gst_element_factory_get_author (GstElementFactory * factory)
591 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
593 return factory->details.author;
597 * gst_element_factory_get_num_pad_templates:
598 * @factory: a #GstElementFactory
600 * Gets the number of pad_templates in this factory.
602 * Returns: the number of pad_templates
605 gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
607 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
609 return factory->numpadtemplates;
613 * __gst_element_factory_add_interface:
614 * @elementfactory: The elementfactory to add the interface to
615 * @interfacename: Name of the interface
617 * Adds the given interfacename to the list of implemented interfaces of the
621 __gst_element_factory_add_interface (GstElementFactory * elementfactory,
622 const gchar * interfacename)
624 g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
625 g_return_if_fail (interfacename != NULL);
626 g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
628 elementfactory->interfaces =
629 g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
633 * gst_element_factory_get_static_pad_templates:
634 * @factory: a #GstElementFactory
636 * Gets the #GList of #GstStaticPadTemplate for this factory.
638 * Returns: the padtemplates
640 G_CONST_RETURN GList *
641 gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
643 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
645 return factory->staticpadtemplates;
649 * gst_element_factory_get_uri_type:
650 * @factory: a #GstElementFactory
652 * Gets the type of URIs the element supports or #GST_URI_UNKNOWN if none.
654 * Returns: type of URIs this element supports
657 gst_element_factory_get_uri_type (GstElementFactory * factory)
659 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
661 return factory->uri_type;
665 * gst_element_factory_get_uri_protocols:
666 * @factory: a #GstElementFactory
668 * Gets a NULL-terminated array of protocols this element supports or NULL if
669 * no protocols are supported. You may not change the contents of the returned
670 * array, as it is still owned by the element factory. Use g_strdupv() to
671 * make a copy of the protocol string array if you need to.
673 * Returns: the supported protocols or NULL
676 gst_element_factory_get_uri_protocols (GstElementFactory * factory)
678 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
680 return factory->uri_protocols;
684 * gst_element_factory_has_interface:
685 * @factory: a #GstElementFactory
686 * @interfacename: an interface name
688 * Check if @factory implements the interface with name @interfacename.
690 * Returns: #TRUE when @factory implement the interface.
695 gst_element_factory_has_interface (GstElementFactory * factory,
696 const gchar * interfacename)
700 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
702 for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
703 gchar *iname = (gchar *) walk->data;
705 if (!strcmp (iname, interfacename))