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 }; */
84 GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY", \
85 GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, \
86 "element factories keep information about installed elements"); \
89 G_DEFINE_TYPE_WITH_CODE (GstElementFactory, gst_element_factory,
90 GST_TYPE_PLUGIN_FEATURE, _do_init);
93 gst_element_factory_class_init (GstElementFactoryClass * klass)
95 GObjectClass *gobject_class = (GObjectClass *) klass;
97 parent_class = g_type_class_peek_parent (klass);
99 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_factory_finalize);
103 gst_element_factory_init (GstElementFactory * factory)
105 factory->staticpadtemplates = NULL;
106 factory->numpadtemplates = 0;
108 factory->uri_type = GST_URI_UNKNOWN;
109 factory->uri_protocols = NULL;
111 factory->interfaces = NULL;
115 gst_element_factory_finalize (GObject * object)
117 GstElementFactory *factory = GST_ELEMENT_FACTORY (object);
119 gst_element_factory_cleanup (factory);
120 G_OBJECT_CLASS (parent_class)->finalize (object);
124 * gst_element_factory_find:
125 * @name: name of factory to find
127 * Search for an element factory of the given name. Refs the returned
128 * element factory; caller is responsible for unreffing.
130 * Returns: #GstElementFactory if found, NULL otherwise
133 gst_element_factory_find (const gchar * name)
135 GstPluginFeature *feature;
137 g_return_val_if_fail (name != NULL, NULL);
139 feature = gst_registry_find_feature (gst_registry_get_default (), name,
140 GST_TYPE_ELEMENT_FACTORY);
142 return GST_ELEMENT_FACTORY (feature);
144 /* this isn't an error, for instance when you query if an element factory is
146 GST_LOG ("no such element factory \"%s\"", name);
151 __gst_element_details_clear (GstElementDetails * dp)
153 g_free (dp->longname);
155 g_free (dp->description);
157 memset (dp, 0, sizeof (GstElementDetails));
160 #define VALIDATE_SET(__dest, __src, __entry) \
162 if (g_utf8_validate (__src->__entry, -1, NULL)) { \
163 __dest->__entry = g_strdup (__src->__entry); \
165 g_warning ("Invalid UTF-8 in " G_STRINGIFY (__entry) ": %s", \
167 __dest->__entry = g_strdup ("[ERROR: invalid UTF-8]"); \
172 __gst_element_details_set (GstElementDetails * dest,
173 const GstElementDetails * src)
175 VALIDATE_SET (dest, src, longname);
176 VALIDATE_SET (dest, src, klass);
177 VALIDATE_SET (dest, src, description);
178 VALIDATE_SET (dest, src, author);
182 __gst_element_details_copy (GstElementDetails * dest,
183 const GstElementDetails * src)
185 __gst_element_details_clear (dest);
186 __gst_element_details_set (dest, src);
190 gst_element_factory_cleanup (GstElementFactory * factory)
194 __gst_element_details_clear (&factory->details);
196 g_type_class_unref (g_type_class_peek (factory->type));
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 GstElementFactory *factory;
254 guint n_interfaces, i;
255 GstElementClass *klass;
258 g_return_val_if_fail (name != NULL, FALSE);
259 g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
262 GST_ELEMENT_FACTORY_CAST (g_object_new (GST_TYPE_ELEMENT_FACTORY, NULL));
263 gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
264 GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
267 klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
268 if ((klass->details.longname == NULL) ||
269 (klass->details.klass == NULL) || (klass->details.author == NULL))
272 factory->type = type;
273 __gst_element_details_copy (&factory->details, &klass->details);
274 for (item = klass->padtemplates; item; item = item->next) {
275 GstPadTemplate *templ = item->data;
276 GstStaticPadTemplate *newt;
278 newt = g_new0 (GstStaticPadTemplate, 1);
279 newt->name_template = g_intern_string (templ->name_template);
280 newt->direction = templ->direction;
281 newt->presence = templ->presence;
282 newt->static_caps.string = gst_caps_to_string (templ->caps);
283 factory->staticpadtemplates =
284 g_list_append (factory->staticpadtemplates, newt);
286 factory->numpadtemplates = klass->numpadtemplates;
287 klass->elementfactory = factory;
289 /* special stuff for URI handling */
290 if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
291 GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
292 g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
294 if (!iface || (!iface->get_type && !iface->get_type_full) ||
295 (!iface->get_protocols && !iface->get_protocols_full))
298 factory->uri_type = iface->get_type ();
299 else if (iface->get_type_full)
300 factory->uri_type = iface->get_type_full (factory->type);
301 if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
303 if (iface->get_protocols)
304 factory->uri_protocols = g_strdupv (iface->get_protocols ());
305 else if (iface->get_protocols_full)
306 factory->uri_protocols = iface->get_protocols_full (factory->type);
307 if (!factory->uri_protocols)
311 interfaces = g_type_interfaces (type, &n_interfaces);
312 for (i = 0; i < n_interfaces; i++) {
313 __gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
317 if (plugin && plugin->desc.name) {
318 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name;
320 GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
322 gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);
323 GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;
325 gst_registry_add_feature (gst_registry_get_default (),
326 GST_PLUGIN_FEATURE_CAST (factory));
333 GST_WARNING_OBJECT (factory, "error with uri handler!");
334 gst_element_factory_cleanup (factory);
340 GST_WARNING_OBJECT (factory,
341 "The GstElementDetails don't seem to have been set properly");
342 gst_element_factory_cleanup (factory);
348 * gst_element_factory_create:
349 * @factory: factory to instantiate
350 * @name: name of new element
352 * Create a new element of the type defined by the given elementfactory.
353 * It will be given the name supplied, since all elements require a name as
354 * their first argument.
356 * Returns: new #GstElement or NULL if the element couldn't be created
359 gst_element_factory_create (GstElementFactory * factory, const gchar * name)
362 GstElementClass *oclass;
363 GstElementFactory *newfactory;
365 g_return_val_if_fail (factory != NULL, NULL);
368 GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
371 if (newfactory == NULL)
374 factory = newfactory;
377 GST_INFO ("creating element \"%s\" named \"%s\"",
378 GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
380 GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
382 if (factory->type == 0)
385 /* create an instance of the element, cast so we don't assert on NULL */
386 element = GST_ELEMENT_CAST (g_object_new (factory->type, NULL));
387 if (G_UNLIKELY (element == NULL))
390 /* fill in the pointer to the factory in the element class. The
391 * class will not be unreffed currently.
392 * FIXME: This isn't safe and may leak a refcount on the factory if 2 threads
393 * create the first instance of an element at the same moment */
394 oclass = GST_ELEMENT_GET_CLASS (element);
395 if (G_UNLIKELY (oclass->elementfactory == NULL))
396 oclass->elementfactory = factory;
398 gst_object_unref (factory);
401 gst_object_set_name (GST_OBJECT_CAST (element), name);
403 GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
410 GST_WARNING_OBJECT (factory, "loading plugin returned NULL!");
415 GST_WARNING_OBJECT (factory, "factory has no type");
416 gst_object_unref (factory);
421 GST_WARNING_OBJECT (factory, "could not create element");
422 gst_object_unref (factory);
428 * gst_element_factory_make:
429 * @factoryname: a named factory to instantiate
430 * @name: name of new element
432 * Create a new element of the type defined by the given element factory.
433 * If name is NULL, then the element will receive a guaranteed unique name,
434 * consisting of the element factory name and a number.
435 * If name is given, it will be given the name supplied.
437 * Returns: new #GstElement or NULL if unable to create element
440 gst_element_factory_make (const gchar * factoryname, const gchar * name)
442 GstElementFactory *factory;
445 g_return_val_if_fail (factoryname != NULL, NULL);
447 GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
448 factoryname, GST_STR_NULL (name));
450 factory = gst_element_factory_find (factoryname);
454 GST_LOG_OBJECT (factory, "found factory %p", factory);
455 element = gst_element_factory_create (factory, name);
459 gst_object_unref (factory);
465 GST_INFO ("no such element factory \"%s\"!", factoryname);
470 GST_INFO_OBJECT (factory, "couldn't create instance!");
471 gst_object_unref (factory);
477 __gst_element_factory_add_static_pad_template (GstElementFactory * factory,
478 GstStaticPadTemplate * templ)
480 g_return_if_fail (factory != NULL);
481 g_return_if_fail (templ != NULL);
483 factory->staticpadtemplates =
484 g_list_append (factory->staticpadtemplates, templ);
485 factory->numpadtemplates++;
489 * gst_element_factory_get_element_type:
490 * @factory: factory to get managed #GType from
492 * Get the #GType for elements managed by this factory. The type can
493 * only be retrieved if the element factory is loaded, which can be
494 * assured with gst_plugin_feature_load().
496 * Returns: the #GType for elements managed by this factory or 0 if
497 * the factory is not loaded.
500 gst_element_factory_get_element_type (GstElementFactory * factory)
502 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
504 return factory->type;
508 * gst_element_factory_get_longname:
509 * @factory: a #GstElementFactory
511 * Gets the longname for this factory
513 * Returns: the longname
515 G_CONST_RETURN gchar *
516 gst_element_factory_get_longname (GstElementFactory * factory)
518 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
520 return factory->details.longname;
524 * gst_element_factory_get_klass:
525 * @factory: a #GstElementFactory
527 * Gets the class for this factory.
531 G_CONST_RETURN gchar *
532 gst_element_factory_get_klass (GstElementFactory * factory)
534 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
536 return factory->details.klass;
540 * gst_element_factory_get_description:
541 * @factory: a #GstElementFactory
543 * Gets the description for this factory.
545 * Returns: the description
547 G_CONST_RETURN gchar *
548 gst_element_factory_get_description (GstElementFactory * factory)
550 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
552 return factory->details.description;
556 * gst_element_factory_get_author:
557 * @factory: a #GstElementFactory
559 * Gets the author for this factory.
561 * Returns: the author
563 G_CONST_RETURN gchar *
564 gst_element_factory_get_author (GstElementFactory * factory)
566 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
568 return factory->details.author;
572 * gst_element_factory_get_num_pad_templates:
573 * @factory: a #GstElementFactory
575 * Gets the number of pad_templates in this factory.
577 * Returns: the number of pad_templates
580 gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
582 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
584 return factory->numpadtemplates;
588 * __gst_element_factory_add_interface:
589 * @elementfactory: The elementfactory to add the interface to
590 * @interfacename: Name of the interface
592 * Adds the given interfacename to the list of implemented interfaces of the
596 __gst_element_factory_add_interface (GstElementFactory * elementfactory,
597 const gchar * interfacename)
599 g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
600 g_return_if_fail (interfacename != NULL);
601 g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
603 elementfactory->interfaces =
604 g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
608 * gst_element_factory_get_static_pad_templates:
609 * @factory: a #GstElementFactory
611 * Gets the #GList of #GstStaticPadTemplate for this factory.
613 * Returns: the padtemplates
615 G_CONST_RETURN GList *
616 gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
618 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
620 return factory->staticpadtemplates;
624 * gst_element_factory_get_uri_type:
625 * @factory: a #GstElementFactory
627 * Gets the type of URIs the element supports or #GST_URI_UNKNOWN if none.
629 * Returns: type of URIs this element supports
632 gst_element_factory_get_uri_type (GstElementFactory * factory)
634 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
636 return factory->uri_type;
640 * gst_element_factory_get_uri_protocols:
641 * @factory: a #GstElementFactory
643 * Gets a NULL-terminated array of protocols this element supports or NULL if
644 * no protocols are supported. You may not change the contents of the returned
645 * array, as it is still owned by the element factory. Use g_strdupv() to
646 * make a copy of the protocol string array if you need to.
648 * Returns: the supported protocols or NULL
651 gst_element_factory_get_uri_protocols (GstElementFactory * factory)
653 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
655 return factory->uri_protocols;
659 * gst_element_factory_has_interface:
660 * @factory: a #GstElementFactory
661 * @interfacename: an interface name
663 * Check if @factory implements the interface with name @interfacename.
665 * Returns: #TRUE when @factory implement the interface.
670 gst_element_factory_has_interface (GstElementFactory * factory,
671 const gchar * interfacename)
675 g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
677 for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
678 gchar *iname = (gchar *) walk->data;
680 if (!strcmp (iname, interfacename))