gstreamer/gst/gstelementfactory.c
Stefan Kost e243a41165 gstelementfactory: set object name earlier if applicable
Setting an object name is nice for proper debug logging. Ideally this would
still happens earlier (.e.g when pads are added to an element, its not yet set).
2009-12-14 11:08:48 +02:00

711 lines
20 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
* 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
*
* gstelementfactory.c: GstElementFactory object, support routines
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstelementfactory
* @short_description: Create GstElements from a factory
* @see_also: #GstElement, #GstPlugin, #GstPluginFeature, #GstPadTemplate.
*
* #GstElementFactory is used to create instances of elements. A
* GstElementfactory can be added to a #GstPlugin as it is also a
* #GstPluginFeature.
*
* Use the gst_element_factory_find() and gst_element_factory_create()
* functions to create element instances or use gst_element_factory_make() as a
* convenient shortcut.
*
* The following code example shows you how to create a GstFileSrc element.
*
* <example>
* <title>Using an element factory</title>
* <programlisting language="c">
* #include &lt;gst/gst.h&gt;
*
* GstElement *src;
* GstElementFactory *srcfactory;
*
* gst_init (&amp;argc, &amp;argv);
*
* srcfactory = gst_element_factory_find ("filesrc");
* g_return_if_fail (srcfactory != NULL);
* src = gst_element_factory_create (srcfactory, "src");
* g_return_if_fail (src != NULL);
* ...
* </programlisting>
* </example>
*
* Last reviewed on 2005-11-23 (0.9.5)
*/
#include "gst_private.h"
#include "gstelement.h"
#include "gstinfo.h"
#include "gsturi.h"
#include "gstregistry.h"
#include "glib-compat-private.h"
GST_DEBUG_CATEGORY_STATIC (element_factory_debug);
#define GST_CAT_DEFAULT element_factory_debug
static void gst_element_factory_class_init (GstElementFactoryClass * klass);
static void gst_element_factory_init (GstElementFactory * factory);
static void gst_element_factory_finalize (GObject * object);
void __gst_element_details_clear (GstElementDetails * dp);
static void gst_element_factory_cleanup (GstElementFactory * factory);
static GstPluginFeatureClass *parent_class = NULL;
/* static guint gst_element_factory_signals[LAST_SIGNAL] = { 0 }; */
/* this is defined in gstelement.c */
extern GQuark _gst_elementclass_factory;
#define _do_init \
{ \
GST_DEBUG_CATEGORY_INIT (element_factory_debug, "GST_ELEMENT_FACTORY", \
GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, \
"element factories keep information about installed elements"); \
}
G_DEFINE_TYPE_WITH_CODE (GstElementFactory, gst_element_factory,
GST_TYPE_PLUGIN_FEATURE, _do_init);
static void
gst_element_factory_class_init (GstElementFactoryClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
parent_class = g_type_class_peek_parent (klass);
gobject_class->finalize = gst_element_factory_finalize;
}
static void
gst_element_factory_init (GstElementFactory * factory)
{
factory->staticpadtemplates = NULL;
factory->numpadtemplates = 0;
factory->uri_type = GST_URI_UNKNOWN;
factory->uri_protocols = NULL;
factory->interfaces = NULL;
}
static void
gst_element_factory_finalize (GObject * object)
{
GstElementFactory *factory = GST_ELEMENT_FACTORY (object);
gst_element_factory_cleanup (factory);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
/**
* gst_element_factory_find:
* @name: name of factory to find
*
* Search for an element factory of the given name. Refs the returned
* element factory; caller is responsible for unreffing.
*
* Returns: #GstElementFactory if found, NULL otherwise
*/
GstElementFactory *
gst_element_factory_find (const gchar * name)
{
GstPluginFeature *feature;
g_return_val_if_fail (name != NULL, NULL);
feature = gst_registry_find_feature (gst_registry_get_default (), name,
GST_TYPE_ELEMENT_FACTORY);
if (feature)
return GST_ELEMENT_FACTORY (feature);
/* this isn't an error, for instance when you query if an element factory is
* present */
GST_LOG ("no such element factory \"%s\"", name);
return NULL;
}
void
__gst_element_details_clear (GstElementDetails * dp)
{
g_free (dp->longname);
g_free (dp->klass);
g_free (dp->description);
g_free (dp->author);
memset (dp, 0, sizeof (GstElementDetails));
}
#define VALIDATE_SET(__dest, __src, __entry) \
G_STMT_START { \
if (g_utf8_validate (__src->__entry, -1, NULL)) { \
__dest->__entry = g_strdup (__src->__entry); \
} else { \
g_warning ("Invalid UTF-8 in " G_STRINGIFY (__entry) ": %s", \
__src->__entry); \
__dest->__entry = g_strdup ("[ERROR: invalid UTF-8]"); \
} \
} G_STMT_END
void
__gst_element_details_set (GstElementDetails * dest,
const GstElementDetails * src)
{
VALIDATE_SET (dest, src, longname);
VALIDATE_SET (dest, src, klass);
VALIDATE_SET (dest, src, description);
VALIDATE_SET (dest, src, author);
}
void
__gst_element_details_copy (GstElementDetails * dest,
const GstElementDetails * src)
{
__gst_element_details_clear (dest);
__gst_element_details_set (dest, src);
}
static void
gst_element_factory_cleanup (GstElementFactory * factory)
{
GList *item;
__gst_element_details_clear (&factory->details);
if (factory->type) {
factory->type = G_TYPE_INVALID;
}
for (item = factory->staticpadtemplates; item; item = item->next) {
GstStaticPadTemplate *templ = item->data;
GstCaps *caps = (GstCaps *) & (templ->static_caps);
g_free ((gchar *) templ->static_caps.string);
/* FIXME: this is not threadsafe */
if (caps->refcount == 1) {
GstStructure *structure;
guint i;
for (i = 0; i < caps->structs->len; i++) {
structure = (GstStructure *) gst_caps_get_structure (caps, i);
gst_structure_set_parent_refcount (structure, NULL);
gst_structure_free (structure);
}
g_ptr_array_free (caps->structs, TRUE);
caps->refcount = 0;
}
g_free (templ);
}
g_list_free (factory->staticpadtemplates);
factory->staticpadtemplates = NULL;
factory->numpadtemplates = 0;
factory->uri_type = GST_URI_UNKNOWN;
if (factory->uri_protocols) {
g_strfreev (factory->uri_protocols);
factory->uri_protocols = NULL;
}
g_list_foreach (factory->interfaces, (GFunc) g_free, NULL);
g_list_free (factory->interfaces);
factory->interfaces = NULL;
}
/**
* gst_element_register:
* @plugin: #GstPlugin to register the element with, or NULL for a static
* element (note that passing NULL only works in GStreamer 0.10.13 and later)
* @name: name of elements of this type
* @rank: rank of element (higher rank means more importance when autoplugging)
* @type: GType of element to register
*
* Create a new elementfactory capable of instantiating objects of the
* @type and add the factory to @plugin.
*
* Returns: TRUE, if the registering succeeded, FALSE on error
*/
gboolean
gst_element_register (GstPlugin * plugin, const gchar * name, guint rank,
GType type)
{
GstPluginFeature *existing_feature;
GstRegistry *registry;
GstElementFactory *factory;
GType *interfaces;
guint n_interfaces, i;
GstElementClass *klass;
GList *item;
g_return_val_if_fail (name != NULL, FALSE);
g_return_val_if_fail (g_type_is_a (type, GST_TYPE_ELEMENT), FALSE);
registry = gst_registry_get_default ();
/* check if feature already exists, if it exists there is no need to update it
* when the registry is getting updated, outdated plugins and all their
* features are removed and readded.
*/
existing_feature = gst_registry_lookup_feature (registry, name);
if (existing_feature) {
GST_DEBUG_OBJECT (registry, "update existing feature %p (%s)",
existing_feature, name);
factory = GST_ELEMENT_FACTORY_CAST (existing_feature);
factory->type = type;
existing_feature->loaded = TRUE;
g_type_set_qdata (type, _gst_elementclass_factory, factory);
gst_object_unref (existing_feature);
return TRUE;
}
factory =
GST_ELEMENT_FACTORY_CAST (g_object_newv (GST_TYPE_ELEMENT_FACTORY, 0,
NULL));
gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
GST_LOG_OBJECT (factory, "Created new elementfactory for type %s",
g_type_name (type));
/* provide info needed during class structure setup */
g_type_set_qdata (type, _gst_elementclass_factory, factory);
klass = GST_ELEMENT_CLASS (g_type_class_ref (type));
if ((klass->details.longname == NULL) ||
(klass->details.klass == NULL) || (klass->details.author == NULL))
goto detailserror;
factory->type = type;
__gst_element_details_copy (&factory->details, &klass->details);
for (item = klass->padtemplates; item; item = item->next) {
GstPadTemplate *templ = item->data;
GstStaticPadTemplate *newt;
newt = g_new0 (GstStaticPadTemplate, 1);
newt->name_template = g_intern_string (templ->name_template);
newt->direction = templ->direction;
newt->presence = templ->presence;
newt->static_caps.string = gst_caps_to_string (templ->caps);
factory->staticpadtemplates =
g_list_append (factory->staticpadtemplates, newt);
}
factory->numpadtemplates = klass->numpadtemplates;
/* special stuff for URI handling */
if (g_type_is_a (type, GST_TYPE_URI_HANDLER)) {
GstURIHandlerInterface *iface = (GstURIHandlerInterface *)
g_type_interface_peek (klass, GST_TYPE_URI_HANDLER);
if (!iface || (!iface->get_type && !iface->get_type_full) ||
(!iface->get_protocols && !iface->get_protocols_full))
goto urierror;
if (iface->get_type)
factory->uri_type = iface->get_type ();
else if (iface->get_type_full)
factory->uri_type = iface->get_type_full (factory->type);
if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
goto urierror;
if (iface->get_protocols)
factory->uri_protocols = g_strdupv (iface->get_protocols ());
else if (iface->get_protocols_full)
factory->uri_protocols = iface->get_protocols_full (factory->type);
if (!factory->uri_protocols)
goto urierror;
}
interfaces = g_type_interfaces (type, &n_interfaces);
for (i = 0; i < n_interfaces; i++) {
__gst_element_factory_add_interface (factory, g_type_name (interfaces[i]));
}
g_free (interfaces);
if (plugin && plugin->desc.name) {
GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name;
} else {
GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
}
gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);
GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;
gst_registry_add_feature (registry, GST_PLUGIN_FEATURE_CAST (factory));
return TRUE;
/* ERRORS */
urierror:
{
GST_WARNING_OBJECT (factory, "error with uri handler!");
gst_element_factory_cleanup (factory);
return FALSE;
}
detailserror:
{
GST_WARNING_OBJECT (factory,
"The GstElementDetails don't seem to have been set properly");
gst_element_factory_cleanup (factory);
return FALSE;
}
}
/**
* gst_element_factory_create:
* @factory: factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given elementfactory.
* It will be given the name supplied, since all elements require a name as
* their first argument.
*
* Returns: new #GstElement or NULL if the element couldn't be created
*/
GstElement *
gst_element_factory_create (GstElementFactory * factory, const gchar * name)
{
GstElement *element;
GstElementClass *oclass;
GstElementFactory *newfactory;
g_return_val_if_fail (factory != NULL, NULL);
newfactory =
GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
(factory)));
if (newfactory == NULL)
goto load_failed;
factory = newfactory;
if (name)
GST_INFO ("creating element \"%s\" named \"%s\"",
GST_PLUGIN_FEATURE_NAME (factory), GST_STR_NULL (name));
else
GST_INFO ("creating element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
if (factory->type == 0)
goto no_type;
/* create an instance of the element, cast so we don't assert on NULL
* also set name as early as we can
*/
if (name)
element =
GST_ELEMENT_CAST (g_object_new (factory->type, "name", name, NULL));
else
element = GST_ELEMENT_CAST (g_object_newv (factory->type, 0, NULL));
if (G_UNLIKELY (element == NULL))
goto no_element;
/* fill in the pointer to the factory in the element class. The
* class will not be unreffed currently.
* Be thread safe as there might be 2 threads creating the first instance of
* an element at the same moment
*/
oclass = GST_ELEMENT_GET_CLASS (element);
if (!g_atomic_pointer_compare_and_exchange (
(gpointer) & oclass->elementfactory, NULL, factory))
gst_object_unref (factory);
GST_DEBUG ("created element \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
return element;
/* ERRORS */
load_failed:
{
GST_WARNING_OBJECT (factory,
"loading plugin containing feature %s returned NULL!", name);
return NULL;
}
no_type:
{
GST_WARNING_OBJECT (factory, "factory has no type");
gst_object_unref (factory);
return NULL;
}
no_element:
{
GST_WARNING_OBJECT (factory, "could not create element");
gst_object_unref (factory);
return NULL;
}
}
/**
* gst_element_factory_make:
* @factoryname: a named factory to instantiate
* @name: name of new element
*
* Create a new element of the type defined by the given element factory.
* If name is NULL, then the element will receive a guaranteed unique name,
* consisting of the element factory name and a number.
* If name is given, it will be given the name supplied.
*
* Returns: new #GstElement or NULL if unable to create element
*/
GstElement *
gst_element_factory_make (const gchar * factoryname, const gchar * name)
{
GstElementFactory *factory;
GstElement *element;
g_return_val_if_fail (factoryname != NULL, NULL);
GST_LOG ("gstelementfactory: make \"%s\" \"%s\"",
factoryname, GST_STR_NULL (name));
factory = gst_element_factory_find (factoryname);
if (factory == NULL)
goto no_factory;
GST_LOG_OBJECT (factory, "found factory %p", factory);
element = gst_element_factory_create (factory, name);
if (element == NULL)
goto create_failed;
gst_object_unref (factory);
return element;
/* ERRORS */
no_factory:
{
GST_INFO ("no such element factory \"%s\"!", factoryname);
return NULL;
}
create_failed:
{
GST_INFO_OBJECT (factory, "couldn't create instance!");
gst_object_unref (factory);
return NULL;
}
}
void
__gst_element_factory_add_static_pad_template (GstElementFactory * factory,
GstStaticPadTemplate * templ)
{
g_return_if_fail (factory != NULL);
g_return_if_fail (templ != NULL);
factory->staticpadtemplates =
g_list_append (factory->staticpadtemplates, templ);
factory->numpadtemplates++;
}
/**
* gst_element_factory_get_element_type:
* @factory: factory to get managed #GType from
*
* Get the #GType for elements managed by this factory. The type can
* only be retrieved if the element factory is loaded, which can be
* assured with gst_plugin_feature_load().
*
* Returns: the #GType for elements managed by this factory or 0 if
* the factory is not loaded.
*/
GType
gst_element_factory_get_element_type (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
return factory->type;
}
/**
* gst_element_factory_get_longname:
* @factory: a #GstElementFactory
*
* Gets the longname for this factory
*
* Returns: the longname
*/
G_CONST_RETURN gchar *
gst_element_factory_get_longname (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.longname;
}
/**
* gst_element_factory_get_klass:
* @factory: a #GstElementFactory
*
* Gets the class for this factory.
*
* Returns: the class
*/
G_CONST_RETURN gchar *
gst_element_factory_get_klass (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.klass;
}
/**
* gst_element_factory_get_description:
* @factory: a #GstElementFactory
*
* Gets the description for this factory.
*
* Returns: the description
*/
G_CONST_RETURN gchar *
gst_element_factory_get_description (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.description;
}
/**
* gst_element_factory_get_author:
* @factory: a #GstElementFactory
*
* Gets the author for this factory.
*
* Returns: the author
*/
G_CONST_RETURN gchar *
gst_element_factory_get_author (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->details.author;
}
/**
* gst_element_factory_get_num_pad_templates:
* @factory: a #GstElementFactory
*
* Gets the number of pad_templates in this factory.
*
* Returns: the number of pad_templates
*/
guint
gst_element_factory_get_num_pad_templates (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), 0);
return factory->numpadtemplates;
}
/**
* __gst_element_factory_add_interface:
* @elementfactory: The elementfactory to add the interface to
* @interfacename: Name of the interface
*
* Adds the given interfacename to the list of implemented interfaces of the
* element.
*/
void
__gst_element_factory_add_interface (GstElementFactory * elementfactory,
const gchar * interfacename)
{
g_return_if_fail (GST_IS_ELEMENT_FACTORY (elementfactory));
g_return_if_fail (interfacename != NULL);
g_return_if_fail (interfacename[0] != '\0'); /* no empty string */
elementfactory->interfaces =
g_list_prepend (elementfactory->interfaces, g_strdup (interfacename));
}
/**
* gst_element_factory_get_static_pad_templates:
* @factory: a #GstElementFactory
*
* Gets the #GList of #GstStaticPadTemplate for this factory.
*
* Returns: the padtemplates
*/
G_CONST_RETURN GList *
gst_element_factory_get_static_pad_templates (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->staticpadtemplates;
}
/**
* gst_element_factory_get_uri_type:
* @factory: a #GstElementFactory
*
* Gets the type of URIs the element supports or #GST_URI_UNKNOWN if none.
*
* Returns: type of URIs this element supports
*/
gint
gst_element_factory_get_uri_type (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), GST_URI_UNKNOWN);
return factory->uri_type;
}
/**
* gst_element_factory_get_uri_protocols:
* @factory: a #GstElementFactory
*
* Gets a NULL-terminated array of protocols this element supports or NULL if
* no protocols are supported. You may not change the contents of the returned
* array, as it is still owned by the element factory. Use g_strdupv() to
* make a copy of the protocol string array if you need to.
*
* Returns: the supported protocols or NULL
*/
gchar **
gst_element_factory_get_uri_protocols (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return factory->uri_protocols;
}
/**
* gst_element_factory_has_interface:
* @factory: a #GstElementFactory
* @interfacename: an interface name
*
* Check if @factory implements the interface with name @interfacename.
*
* Returns: #TRUE when @factory implement the interface.
*
* Since: 0.10.14
*/
gboolean
gst_element_factory_has_interface (GstElementFactory * factory,
const gchar * interfacename)
{
GList *walk;
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), FALSE);
for (walk = factory->interfaces; walk; walk = g_list_next (walk)) {
gchar *iname = (gchar *) walk->data;
if (!strcmp (iname, interfacename))
return TRUE;
}
return FALSE;
}