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>
44 * GstElementFactory *srcfactory;
45 * gst_init(&argc,&argv);
46 * srcfactory = gst_element_factory_find("filesrc");
47 * g_return_if_fail(srcfactory != NULL);
48 * src = gst_element_factory_create(srcfactory,"src");
49 * g_return_if_fail(src != NULL);
54 * Last reviewed on 2005-11-23 (0.9.5)
57 #include "gst_private.h"
59 #include "gstelement.h"
62 #include "gstregistry.h"
64 #include "glib-compat-private.h"
66 GST_DEBUG_CATEGORY_STATIC (element_factory_debug);
67 #define GST_CAT_DEFAULT element_factory_debug
69 static void gst_element_factory_class_init (GstElementFactoryClass * klass);
70 static void gst_element_factory_init (GstElementFactory * factory);
71 static void gst_element_factory_finalize (GObject * object);
72 void __gst_element_details_clear (GstElementDetails * dp);
73 static void gst_element_factory_cleanup (GstElementFactory * factory);
75 static GstPluginFeatureClass *parent_class = NULL;
77 /* static guint gst_element_factory_signals[LAST_SIGNAL] = { 0 }; */
80 gst_element_factory_get_type (void)
82 static GType elementfactory_type = 0;
84 if (G_UNLIKELY (elementfactory_type == 0)) {
85 static const GTypeInfo elementfactory_info = {
86 sizeof (GstElementFactoryClass),
89 (GClassInitFunc) gst_element_factory_class_init,
92 sizeof (GstElementFactory),
94 (GInstanceInitFunc) gst_element_factory_init,
98 elementfactory_type = g_type_register_static (GST_TYPE_PLUGIN_FEATURE,
99 "GstElementFactory", &elementfactory_info, 0);
100 GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY",
101 GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED,
102 "element factories keep information about installed elements");
104 return elementfactory_type;
107 gst_element_factory_class_init (GstElementFactoryClass * klass)
109 GObjectClass *gobject_class;
110 GstObjectClass *gstobject_class;
111 GstPluginFeatureClass *gstpluginfeature_class;
113 gobject_class = (GObjectClass *) klass;
114 gstobject_class = (GstObjectClass *) klass;
115 gstpluginfeature_class = (GstPluginFeatureClass *) klass;
117 parent_class = g_type_class_peek_parent (klass);
119 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_factory_finalize);
123 gst_element_factory_init (GstElementFactory * factory)
125 factory->staticpadtemplates = NULL;
126 factory->numpadtemplates = 0;
128 factory->uri_type = GST_URI_UNKNOWN;
129 factory->uri_protocols = NULL;
131 factory->interfaces = NULL;
135 gst_element_factory_finalize (GObject * object)
137 GstElementFactory *factory = GST_ELEMENT_FACTORY (object);
139 gst_element_factory_cleanup (factory);
140 G_OBJECT_CLASS (parent_class)->finalize (object);
144 * gst_element_factory_find:
145 * @name: name of factory to find
147 * Search for an element factory of the given name. Refs the returned
148 * element factory; caller is responsible for unreffing.
150 * Returns: #GstElementFactory if found, NULL otherwise
153 gst_element_factory_find (const gchar * name)
155 GstPluginFeature *feature;
157 g_return_val_if_fail (name != NULL, NULL);
159 feature = gst_registry_find_feature (gst_registry_get_default (), name,
160 GST_TYPE_ELEMENT_FACTORY);
162 return GST_ELEMENT_FACTORY (feature);
164 /* this isn't an error, for instance when you query if an element factory is
166 GST_LOG ("no such element factory \"%s\"", name);
171 __gst_element_details_clear (GstElementDetails * dp)
173 g_free (dp->longname);
175 g_free (dp->description);
177 memset (dp, 0, sizeof (GstElementDetails));
180 #define VALIDATE_SET(__dest, __src, __entry) \
182 if (g_utf8_validate (__src->__entry, -1, NULL)) { \
183 __dest->__entry = g_strdup (__src->__entry); \
185 g_warning ("Invalid UTF-8 in " G_STRINGIFY (__entry) ": %s", \
187 __dest->__entry = g_strdup ("[ERROR: invalid UTF-8]"); \
192 __gst_element_details_set (GstElementDetails * dest,
193 const GstElementDetails * src)
195 VALIDATE_SET (dest, src, longname);
196 VALIDATE_SET (dest, src, klass);
197 VALIDATE_SET (dest, src, description);
198 VALIDATE_SET (dest, src, author);
202 __gst_element_details_copy (GstElementDetails * dest,
203 const GstElementDetails * src)
205 __gst_element_details_clear (dest);
206 __gst_element_details_set (dest, src);
210 gst_element_factory_cleanup (GstElementFactory * factory)
214 __gst_element_details_clear (&factory->details);
216 g_type_class_unref (g_type_class_peek (factory->type));
220 for (item = factory->staticpadtemplates; item; item = item->next) {
221 GstStaticPadTemplate *templ = item->data;
222 GstCaps *caps = (GstCaps *) & (templ->static_caps);
224 g_free ((gchar *) templ->static_caps.string);
226 /* FIXME: this is not threadsafe */
227 if (caps->refcount == 1) {
228 GstStructure *structure;
231 for (i = 0; i < caps->structs->len; i++) {
232 structure = (GstStructure *) gst_caps_get_structure (caps, i);
233 gst_structure_set_parent_refcount (structure, NULL);
234 gst_structure_free (structure);
236 g_ptr_array_free (caps->structs, TRUE);
241 g_list_free (factory->staticpadtemplates);
242 factory->staticpadtemplates = NULL;
243 factory->numpadtemplates = 0;
244 factory->uri_type = GST_URI_UNKNOWN;
245 if (factory->uri_protocols) {
246 g_strfreev (factory->uri_protocols);
247 factory->uri_protocols = NULL;
250 g_list_foreach (factory->interfaces, (GFunc) g_free, NULL);
251 g_list_free (factory->interfaces);
252 factory->interfaces = NULL;
256 * gst_element_register:
257 * @plugin: #GstPlugin to register the element with, or NULL for a static
258 * element (note that passing NULL only works in GStreamer 0.10.13 and later)
259 * @name: name of elements of this type
260 * @rank: rank of element (higher rank means more importance when autoplugging)
261 * @type: GType of element to register
263 * Create a new elementfactory capable of instantiating objects of the
264 * @type and add the factory to @plugin.
266 * Returns: TRUE, if the registering succeeded, FALSE on error
269 gst_element_register (GstPlugin * plugin, const gchar * name, guint rank,
272 GstElementFactory *factory;
274 guint n_interfaces, i;
275 GstElementClass *klass;
278 g_return_val_if_fail (name != NULL, FALSE);
279 g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
281 factory = GST_ELEMENT_FACTORY (g_object_new (GST_TYPE_ELEMENT_FACTORY, NULL));
282 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE (factory), name);
283 GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
286 klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
287 if ((klass->details.longname == NULL) ||
288 (klass->details.klass == NULL) || (klass->details.author == NULL))
291 factory->type = type;
292 __gst_element_details_copy (&factory->details, &klass->details);
293 for (item = klass->padtemplates; item; item = item->next) {
294 GstPadTemplate *templ = item->data;
295 GstStaticPadTemplate *newt;
297 newt = g_new0 (GstStaticPadTemplate, 1);
298 newt->name_template = g_intern_string (templ->name_template);
299 newt->direction = templ->direction;
300 newt->presence = templ->presence;
301 newt->static_caps.string = gst_caps_to_string (templ->caps);
302 factory->staticpadtemplates =
303 g_list_append (factory->staticpadtemplates, newt);
305 factory->numpadtemplates = klass->numpadtemplates;
306 klass->elementfactory = factory;
308 /* special stuff for URI handling */
309 if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
310 GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
311 g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
313 if (!iface || (!iface->get_type && !iface->get_type_full) ||
314 (!iface->get_protocols && !iface->get_protocols_full))
317 factory->uri_type = iface->get_type ();
318 else if (iface->get_type_full)
319 factory->uri_type = iface->get_type_full (factory->type);
320 if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
322 if (iface->get_protocols)
323 factory->uri_protocols = g_strdupv (iface->get_protocols ());
324 else if (iface->get_protocols_full)
325 factory->uri_protocols = iface->get_protocols_full (factory->type);
326 if (!factory->uri_protocols)
330 interfaces = g_type_interfaces (type, &n_interfaces);
331 for (i = 0; i < n_interfaces; i++) {
332 __gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
336 if (plugin && plugin->desc.name) {
337 GST_PLUGIN_FEATURE (factory)->plugin_name = plugin->desc.name;
339 GST_PLUGIN_FEATURE (factory)->plugin_name = "NULL";
341 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE (factory), rank);
342 GST_PLUGIN_FEATURE (factory)->loaded = TRUE;
344 gst_registry_add_feature (gst_registry_get_default (),
345 GST_PLUGIN_FEATURE (factory));
352 GST_WARNING_OBJECT (factory, "error with uri handler!");
353 gst_element_factory_cleanup (factory);
359 GST_WARNING_OBJECT (factory,
360 "The GstElementDetails don't seem to have been set properly");
361 gst_element_factory_cleanup (factory);
367 * gst_element_factory_create:
368 * @factory: factory to instantiate
369 * @name: name of new element
371 * Create a new element of the type defined by the given elementfactory.
372 * It will be given the name supplied, since all elements require a name as
373 * their first argument.
375 * Returns: new #GstElement or NULL if the element couldn't be created
378 gst_element_factory_create (GstElementFactory * factory, const gchar * name)
381 GstElementClass *oclass;
382 GstElementFactory *newfactory;
384 g_return_val_if_fail (factory != NULL, NULL);
387 GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
390 if (newfactory == NULL)
393 factory = newfactory;
396 GST_INFO ("creating element \"%s\" named \"%s\"",
397 GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
399 GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
401 if (factory->type == 0)
404 /* create an instance of the element, cast so we don't assert on NULL */
405 element = GST_ELEMENT_CAST (g_object_new (factory->type, NULL));
406 if (G_UNLIKELY (element == NULL))
409 /* fill in the pointer to the factory in the element class. The
410 * class will not be unreffed currently.
411 * FIXME: This isn't safe and may leak a refcount on the factory if 2 threads
412 * create the first instance of an element at the same moment */
413 oclass = GST_ELEMENT_GET_CLASS (element);
414 if (G_UNLIKELY (oclass->elementfactory == NULL))
415 oclass->elementfactory = factory;
417 gst_object_unref (factory);
420 gst_object_set_name (GST_OBJECT (element), name);
422 GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
429 GST_WARNING_OBJECT (factory, "loading plugin returned NULL!");
434 GST_WARNING_OBJECT (factory, "factory has no type");
435 gst_object_unref (factory);
440 GST_WARNING_OBJECT (factory, "could not create element");
441 gst_object_unref (factory);
447 * gst_element_factory_make:
448 * @factoryname: a named factory to instantiate
449 * @name: name of new element
451 * Create a new element of the type defined by the given element factory.
452 * If name is NULL, then the element will receive a guaranteed unique name,
453 * consisting of the element factory name and a number.
454 * If name is given, it will be given the name supplied.
456 * Returns: new #GstElement or NULL if unable to create element
459 gst_element_factory_make (const gchar * factoryname, const gchar * name)
461 GstElementFactory *factory;
464 g_return_val_if_fail (factoryname != NULL, NULL);
466 GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
467 factoryname, GST_STR_NULL (name));
469 factory = gst_element_factory_find (factoryname);
473 GST_LOG_OBJECT (factory, "found factory %p", factory);
474 element = gst_element_factory_create (factory, name);
478 gst_object_unref (factory);
484 GST_INFO ("no such element factory \"%s\"!", factoryname);
489 GST_INFO_OBJECT (factory, "couldn't create instance!");
490 gst_object_unref (factory);
496 __gst_element_factory_add_static_pad_template (GstElementFactory * factory,
497 GstStaticPadTemplate * templ)
499 g_return_if_fail (factory != NULL);
500 g_return_if_fail (templ != NULL);
502 factory->staticpadtemplates =
503 g_list_append (factory->staticpadtemplates, templ);
504 factory->numpadtemplates++;
508 * gst_element_factory_get_element_type:
509 * @factory: factory to get managed #GType from
511 * Get the #GType for elements managed by this factory. The type can
512 * only be retrieved if the element factory is loaded, which can be
513 * assured with gst_plugin_feature_load().
515 * Returns: the #GType for elements managed by this factory or 0 if
516 * the factory is not loaded.
519 gst_element_factory_get_element_type (GstElementFactory * factory)
521 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
523 return factory->type;
527 * gst_element_factory_get_longname:
528 * @factory: a #GstElementFactory
530 * Gets the longname for this factory
532 * Returns: the longname
534 G_CONST_RETURN gchar *
535 gst_element_factory_get_longname (GstElementFactory * factory)
537 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
539 return factory->details.longname;
543 * gst_element_factory_get_klass:
544 * @factory: a #GstElementFactory
546 * Gets the class for this factory.
550 G_CONST_RETURN gchar *
551 gst_element_factory_get_klass (GstElementFactory * factory)
553 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
555 return factory->details.klass;
559 * gst_element_factory_get_description:
560 * @factory: a #GstElementFactory
562 * Gets the description for this factory.
564 * Returns: the description
566 G_CONST_RETURN gchar *
567 gst_element_factory_get_description (GstElementFactory * factory)
569 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
571 return factory->details.description;
575 * gst_element_factory_get_author:
576 * @factory: a #GstElementFactory
578 * Gets the author for this factory.
580 * Returns: the author
582 G_CONST_RETURN gchar *
583 gst_element_factory_get_author (GstElementFactory * factory)
585 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
587 return factory->details.author;
591 * gst_element_factory_get_num_pad_templates:
592 * @factory: a #GstElementFactory
594 * Gets the number of pad_templates in this factory.
596 * Returns: the number of pad_templates
599 gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
601 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
603 return factory->numpadtemplates;
607 * __gst_element_factory_add_interface:
608 * @elementfactory: The elementfactory to add the interface to
609 * @interfacename: Name of the interface
611 * Adds the given interfacename to the list of implemented interfaces of the
615 __gst_element_factory_add_interface (GstElementFactory * elementfactory,
616 const gchar * interfacename)
618 g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
619 g_return_if_fail (interfacename != NULL);
620 g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
622 elementfactory->interfaces =
623 g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
627 * gst_element_factory_get_static_pad_templates:
628 * @factory: a #GstElementFactory
630 * Gets the #GList of #GstStaticPadTemplate for this factory.
632 * Returns: the padtemplates
634 G_CONST_RETURN GList *
635 gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
637 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
639 return factory->staticpadtemplates;
643 * gst_element_factory_get_uri_type:
644 * @factory: a #GstElementFactory
646 * Gets the type of URIs the element supports or GST_URI_UNKNOWN if none.
648 * Returns: type of URIs this element supports
651 gst_element_factory_get_uri_type (GstElementFactory * factory)
653 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
655 return factory->uri_type;
659 * gst_element_factory_get_uri_protocols:
660 * @factory: a #GstElementFactory
662 * Gets a NULL-terminated array of protocols this element supports or NULL if
663 * no protocols are supported. You may not change the contents of the returned
664 * array, as it is still owned by the element factory. Use g_strdupv() to
665 * make a copy of the protocol string array if you need to.
667 * Returns: the supported protocols or NULL
670 gst_element_factory_get_uri_protocols (GstElementFactory * factory)
672 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
674 return factory->uri_protocols;
678 * gst_element_factory_has_interface:
679 * @factory: a #GstElementFactory
680 * @interfacename: an interface name
682 * Check if @factory implements the interface with name @interfacename.
684 * Returns: #TRUE when @factory implement the interface.
689 gst_element_factory_has_interface (GstElementFactory * factory,
690 const gchar * interfacename)
694 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
696 for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
697 gchar *iname = (gchar *) walk->data;
699 if (!strcmp (iname, interfacename))