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"
63 #include "gstelementdetails.h"
66 #include "gstregistry.h"
68 #include "glib-compat-private.h"
70 GST_DEBUG_CATEGORY_STATIC (element_factory_debug);
71 #define GST_CAT_DEFAULT element_factory_debug
73 static void gst_element_factory_finalize (GObject * object);
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_factory_cleanup (GstElementFactory * factory)
156 __gst_element_details_clear (&factory->details);
158 factory->type = G_TYPE_INVALID;
161 for (item = factory->staticpadtemplates; item; item = item->next) {
162 GstStaticPadTemplate *templ = item->data;
163 GstCaps *caps = (GstCaps *) & (templ->static_caps);
165 g_free ((gchar *) templ->static_caps.string);
167 /* FIXME: this is not threadsafe */
168 if (caps->refcount == 1) {
169 GstStructure *structure;
172 for (i = 0; i < caps->structs->len; i++) {
173 structure = (GstStructure *) gst_caps_get_structure (caps, i);
174 gst_structure_set_parent_refcount (structure, NULL);
175 gst_structure_free (structure);
177 g_ptr_array_free (caps->structs, TRUE);
182 g_list_free (factory->staticpadtemplates);
183 factory->staticpadtemplates = NULL;
184 factory->numpadtemplates = 0;
185 factory->uri_type = GST_URI_UNKNOWN;
186 if (factory->uri_protocols) {
187 g_strfreev (factory->uri_protocols);
188 factory->uri_protocols = NULL;
191 g_list_foreach (factory->interfaces, (GFunc) g_free, NULL);
192 g_list_free (factory->interfaces);
193 factory->interfaces = NULL;
197 * gst_element_register:
198 * @plugin: #GstPlugin to register the element with, or NULL for a static
199 * element (note that passing NULL only works in GStreamer 0.10.13 and later)
200 * @name: name of elements of this type
201 * @rank: rank of element (higher rank means more importance when autoplugging)
202 * @type: GType of element to register
204 * Create a new elementfactory capable of instantiating objects of the
205 * @type and add the factory to @plugin.
207 * Returns: TRUE, if the registering succeeded, FALSE on error
210 gst_element_register (GstPlugin * plugin, const gchar * name, guint rank,
213 GstPluginFeature *existing_feature;
214 GstRegistry *registry;
215 GstElementFactory *factory;
217 guint n_interfaces, i;
218 GstElementClass *klass;
221 g_return_val_if_fail (name != NULL, FALSE);
222 g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
224 registry = gst_registry_get_default ();
226 /* check if feature already exists, if it exists there is no need to update it
227 * when the registry is getting updated, outdated plugins and all their
228 * features are removed and readded.
230 existing_feature = gst_registry_lookup_feature (registry, name);
231 if (existing_feature) {
232 GST_DEBUG_OBJECT (registry, "update existing feature %p (%s)",
233 existing_feature, name);
234 factory = GST_ELEMENT_FACTORY_CAST (existing_feature);
235 factory->type = type;
236 existing_feature->loaded = TRUE;
237 g_type_set_qdata (type, _gst_elementclass_factory, factory);
238 gst_object_unref (existing_feature);
243 GST_ELEMENT_FACTORY_CAST (g_object_newv (GST_TYPE_ELEMENT_FACTORY, 0,
245 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
246 GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
249 /* provide info needed during class structure setup */
250 g_type_set_qdata (type, _gst_elementclass_factory, factory);
251 klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
252 if ((klass->details.longname == NULL) ||
253 (klass->details.klass == NULL) || (klass->details.author == NULL))
256 factory->type = type;
257 __gst_element_details_copy (&factory->details, &klass->details);
258 for (item = klass->padtemplates; item; item = item->next) {
259 GstPadTemplate *templ = item->data;
260 GstStaticPadTemplate *newt;
262 newt = g_new0 (GstStaticPadTemplate, 1);
263 newt->name_template = g_intern_string (templ->name_template);
264 newt->direction = templ->direction;
265 newt->presence = templ->presence;
266 newt->static_caps.string = gst_caps_to_string (templ->caps);
267 factory->staticpadtemplates =
268 g_list_append (factory->staticpadtemplates, newt);
270 factory->numpadtemplates = klass->numpadtemplates;
272 /* special stuff for URI handling */
273 if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
274 GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
275 g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
277 if (!iface || (!iface->get_type && !iface->get_type_full) ||
278 (!iface->get_protocols && !iface->get_protocols_full))
281 factory->uri_type = iface->get_type ();
282 else if (iface->get_type_full)
283 factory->uri_type = iface->get_type_full (factory->type);
284 if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
286 if (iface->get_protocols)
287 factory->uri_protocols = g_strdupv (iface->get_protocols ());
288 else if (iface->get_protocols_full)
289 factory->uri_protocols = iface->get_protocols_full (factory->type);
290 if (!factory->uri_protocols)
294 interfaces = g_type_interfaces (type, &n_interfaces);
295 for (i = 0; i < n_interfaces; i++) {
296 __gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
300 if (plugin && plugin->desc.name) {
301 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name;
303 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
305 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);
306 GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;
308 gst_registry_add_feature (registry, GST_PLUGIN_FEATURE_CAST (factory));
315 GST_WARNING_OBJECT (factory, "error with uri handler!");
316 gst_element_factory_cleanup (factory);
322 GST_WARNING_OBJECT (factory,
323 "The GstElementDetails don't seem to have been set properly");
324 gst_element_factory_cleanup (factory);
330 * gst_element_factory_create:
331 * @factory: factory to instantiate
332 * @name: name of new element
334 * Create a new element of the type defined by the given elementfactory.
335 * It will be given the name supplied, since all elements require a name as
336 * their first argument.
338 * Returns: new #GstElement or NULL if the element couldn't be created
341 gst_element_factory_create (GstElementFactory * factory, const gchar * name)
344 GstElementClass *oclass;
345 GstElementFactory *newfactory;
347 g_return_val_if_fail (factory != NULL, NULL);
350 GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
353 if (newfactory == NULL)
356 factory = newfactory;
359 GST_INFO ("creating element \"%s\" named \"%s\"",
360 GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
362 GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
364 if (factory->type == 0)
367 /* create an instance of the element, cast so we don't assert on NULL
368 * also set name as early as we can
372 GST_ELEMENT_CAST (g_object_new (factory->type, "name", name, NULL));
374 element = GST_ELEMENT_CAST (g_object_newv (factory->type, 0, NULL));
375 if (G_UNLIKELY (element == NULL))
378 /* fill in the pointer to the factory in the element class. The
379 * class will not be unreffed currently.
380 * Be thread safe as there might be 2 threads creating the first instance of
381 * an element at the same moment
383 oclass = GST_ELEMENT_GET_CLASS (element);
384 if (!g_atomic_pointer_compare_and_exchange (
385 (gpointer) & oclass->elementfactory, NULL, factory))
386 gst_object_unref (factory);
388 GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
395 GST_WARNING_OBJECT (factory,
396 "loading plugin containing feature %s returned NULL!", name);
401 GST_WARNING_OBJECT (factory, "factory has no type");
402 gst_object_unref (factory);
407 GST_WARNING_OBJECT (factory, "could not create element");
408 gst_object_unref (factory);
414 * gst_element_factory_make:
415 * @factoryname: a named factory to instantiate
416 * @name: name of new element
418 * Create a new element of the type defined by the given element factory.
419 * If name is NULL, then the element will receive a guaranteed unique name,
420 * consisting of the element factory name and a number.
421 * If name is given, it will be given the name supplied.
423 * Returns: new #GstElement or NULL if unable to create element
426 gst_element_factory_make (const gchar * factoryname, const gchar * name)
428 GstElementFactory *factory;
431 g_return_val_if_fail (factoryname != NULL, NULL);
433 GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
434 factoryname, GST_STR_NULL (name));
436 factory = gst_element_factory_find (factoryname);
440 GST_LOG_OBJECT (factory, "found factory %p", factory);
441 element = gst_element_factory_create (factory, name);
445 gst_object_unref (factory);
451 GST_INFO ("no such element factory \"%s\"!", factoryname);
456 GST_INFO_OBJECT (factory, "couldn't create instance!");
457 gst_object_unref (factory);
463 __gst_element_factory_add_static_pad_template (GstElementFactory * factory,
464 GstStaticPadTemplate * templ)
466 g_return_if_fail (factory != NULL);
467 g_return_if_fail (templ != NULL);
469 factory->staticpadtemplates =
470 g_list_append (factory->staticpadtemplates, templ);
471 factory->numpadtemplates++;
475 * gst_element_factory_get_element_type:
476 * @factory: factory to get managed #GType from
478 * Get the #GType for elements managed by this factory. The type can
479 * only be retrieved if the element factory is loaded, which can be
480 * assured with gst_plugin_feature_load().
482 * Returns: the #GType for elements managed by this factory or 0 if
483 * the factory is not loaded.
486 gst_element_factory_get_element_type (GstElementFactory * factory)
488 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
490 return factory->type;
494 * gst_element_factory_get_longname:
495 * @factory: a #GstElementFactory
497 * Gets the longname for this factory
499 * Returns: the longname
501 G_CONST_RETURN gchar *
502 gst_element_factory_get_longname (GstElementFactory * factory)
504 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
506 return factory->details.longname;
510 * gst_element_factory_get_klass:
511 * @factory: a #GstElementFactory
513 * Gets the class for this factory.
517 G_CONST_RETURN gchar *
518 gst_element_factory_get_klass (GstElementFactory * factory)
520 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
522 return factory->details.klass;
526 * gst_element_factory_get_description:
527 * @factory: a #GstElementFactory
529 * Gets the description for this factory.
531 * Returns: the description
533 G_CONST_RETURN gchar *
534 gst_element_factory_get_description (GstElementFactory * factory)
536 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
538 return factory->details.description;
542 * gst_element_factory_get_author:
543 * @factory: a #GstElementFactory
545 * Gets the author for this factory.
547 * Returns: the author
549 G_CONST_RETURN gchar *
550 gst_element_factory_get_author (GstElementFactory * factory)
552 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
554 return factory->details.author;
558 * gst_element_factory_get_num_pad_templates:
559 * @factory: a #GstElementFactory
561 * Gets the number of pad_templates in this factory.
563 * Returns: the number of pad_templates
566 gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
568 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
570 return factory->numpadtemplates;
574 * __gst_element_factory_add_interface:
575 * @elementfactory: The elementfactory to add the interface to
576 * @interfacename: Name of the interface
578 * Adds the given interfacename to the list of implemented interfaces of the
582 __gst_element_factory_add_interface (GstElementFactory * elementfactory,
583 const gchar * interfacename)
585 g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
586 g_return_if_fail (interfacename != NULL);
587 g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
589 elementfactory->interfaces =
590 g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
594 * gst_element_factory_get_static_pad_templates:
595 * @factory: a #GstElementFactory
597 * Gets the #GList of #GstStaticPadTemplate for this factory.
599 * Returns: the padtemplates
601 G_CONST_RETURN GList *
602 gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
604 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
606 return factory->staticpadtemplates;
610 * gst_element_factory_get_uri_type:
611 * @factory: a #GstElementFactory
613 * Gets the type of URIs the element supports or #GST_URI_UNKNOWN if none.
615 * Returns: type of URIs this element supports
618 gst_element_factory_get_uri_type (GstElementFactory * factory)
620 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
622 return factory->uri_type;
626 * gst_element_factory_get_uri_protocols:
627 * @factory: a #GstElementFactory
629 * Gets a NULL-terminated array of protocols this element supports or NULL if
630 * no protocols are supported. You may not change the contents of the returned
631 * array, as it is still owned by the element factory. Use g_strdupv() to
632 * make a copy of the protocol string array if you need to.
634 * Returns: the supported protocols or NULL
637 gst_element_factory_get_uri_protocols (GstElementFactory * factory)
639 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
641 return factory->uri_protocols;
645 * gst_element_factory_has_interface:
646 * @factory: a #GstElementFactory
647 * @interfacename: an interface name
649 * Check if @factory implements the interface with name @interfacename.
651 * Returns: #TRUE when @factory implement the interface.
656 gst_element_factory_has_interface (GstElementFactory * factory,
657 const gchar * interfacename)
661 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
663 for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
664 gchar *iname = (gchar *) walk->data;
666 if (!strcmp (iname, interfacename))