gstreamer/gst/gstelementfactory.c
Christoph Reiter 3cfda6d6eb gstelementfactory: Fix missing features in case a feature moves to another filename
In case a plugin filename was renamed with the plugin being in the registry cache
the features were not loaded after the rename:

1) Cache of old/gone filename was loaded, features added
2) New filename was loaded, features where not added because
   they were already found in the registry.
3) In the end stale cache entries for files which are no longer there
   are removed, including the wanted features.
4) The cache gets updated without the features.

Fix this by also checking at (2) that the found feature is from the loaded plugin
and not from some stale cache entry.

This affected directsoundsink where libgstdirectsoundsink.dll was renamed
to libgstdirectsound.dll, losing the directsoundsink element in the process.

Fixes #290

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/102>
2020-07-06 14:31:48 +00:00

893 lines
27 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstelementfactory
* @title: 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.
*
* ## Using an element factory
* |[<!-- 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);
* ...
* ]|
*/
#include "gst_private.h"
#include "gstelement.h"
#include "gstelementmetadata.h"
#include "gstinfo.h"
#include "gsturi.h"
#include "gstregistry.h"
#include "gst.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_finalize (GObject * object);
static void gst_element_factory_cleanup (GstElementFactory * factory);
/* 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;
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 (gst_element_factory_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: (transfer full) (nullable): #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 (), 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;
}
static void
gst_element_factory_cleanup (GstElementFactory * factory)
{
GList *item;
if (factory->metadata) {
gst_structure_free ((GstStructure *) factory->metadata);
factory->metadata = NULL;
}
if (factory->type) {
factory->type = G_TYPE_INVALID;
}
for (item = factory->staticpadtemplates; item; item = item->next) {
GstStaticPadTemplate *templ = item->data;
gst_static_caps_cleanup (&templ->static_caps);
g_slice_free (GstStaticPadTemplate, 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_free (factory->interfaces);
factory->interfaces = NULL;
}
#define CHECK_METADATA_FIELD(klass, name, key) \
G_STMT_START { \
const gchar *metafield = gst_element_class_get_metadata (klass, key); \
if (G_UNLIKELY (metafield == NULL || *metafield == '\0')) { \
g_warning ("Element factory metadata for '%s' has no valid %s field", name, key); \
goto detailserror; \
} \
} G_STMT_END;
/**
* gst_element_register:
* @plugin: (allow-none): #GstPlugin to register the element with, or %NULL for
* a static element.
* @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 ();
/* 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 && existing_feature->plugin == plugin) {
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;
} else if (existing_feature) {
gst_object_unref (existing_feature);
}
factory = g_object_new (GST_TYPE_ELEMENT_FACTORY, 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));
CHECK_METADATA_FIELD (klass, name, GST_ELEMENT_METADATA_LONGNAME);
CHECK_METADATA_FIELD (klass, name, GST_ELEMENT_METADATA_KLASS);
CHECK_METADATA_FIELD (klass, name, GST_ELEMENT_METADATA_DESCRIPTION);
CHECK_METADATA_FIELD (klass, name, GST_ELEMENT_METADATA_AUTHOR);
factory->type = type;
factory->metadata = gst_structure_copy ((GstStructure *) klass->metadata);
for (item = klass->padtemplates; item; item = item->next) {
GstPadTemplate *templ = item->data;
GstStaticPadTemplate *newt;
gchar *caps_string = gst_caps_to_string (templ->caps);
newt = g_slice_new (GstStaticPadTemplate);
newt->name_template = g_intern_string (templ->name_template);
newt->direction = templ->direction;
newt->presence = templ->presence;
newt->static_caps.caps = NULL;
newt->static_caps.string = g_intern_string (caps_string);
factory->staticpadtemplates =
g_list_append (factory->staticpadtemplates, newt);
g_free (caps_string);
}
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_protocols)
goto urierror;
if (iface->get_type)
factory->uri_type = iface->get_type (factory->type);
if (!GST_URI_TYPE_IS_VALID (factory->uri_type))
goto urierror;
if (iface->get_protocols) {
const gchar *const *protocols;
protocols = iface->get_protocols (factory->type);
factory->uri_protocols = g_strdupv ((gchar **) protocols);
}
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;
GST_PLUGIN_FEATURE_CAST (factory)->plugin = plugin;
g_object_add_weak_pointer ((GObject *) plugin,
(gpointer *) & GST_PLUGIN_FEATURE_CAST (factory)->plugin);
} else {
GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
GST_PLUGIN_FEATURE_CAST (factory)->plugin = 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_element_factory_cleanup (factory);
return FALSE;
}
}
/**
* gst_element_factory_create:
* @factory: factory to instantiate
* @name: (allow-none): name of new element, or %NULL to automatically create
* a unique name
*
* 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: (transfer floating) (nullable): 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_OBJECT_NAME (factory), GST_STR_NULL (name));
else
GST_INFO ("creating element \"%s\"", GST_OBJECT_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 = g_object_new (factory->type, "name", name, NULL);
else
element = g_object_new (factory->type, 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 (&oclass->elementfactory, NULL,
factory))
gst_object_unref (factory);
else
/* This ref will never be dropped as the class is never destroyed */
GST_OBJECT_FLAG_SET (factory, GST_OBJECT_FLAG_MAY_BE_LEAKED);
if (!g_object_is_floating ((GObject *) element)) {
/* The reference we receive here should be floating, but we can't force
* it at our level. Simply raise a critical to make the issue obvious to bindings
* users / developers */
g_critical ("The created element should be floating, "
"this is probably caused by faulty bindings");
}
GST_DEBUG ("created element \"%s\"", GST_OBJECT_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: (allow-none): name of new element, or %NULL to automatically create
* a unique name
*
* 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: (transfer floating) (nullable): 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);
g_return_val_if_fail (gst_is_initialized (), 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_WARNING ("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_metadata:
* @factory: a #GstElementFactory
* @key: a key
*
* Get the metadata on @factory with @key.
*
* Returns: (nullable): the metadata with @key on @factory or %NULL
* when there was no metadata with the given @key.
*/
const gchar *
gst_element_factory_get_metadata (GstElementFactory * factory,
const gchar * key)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return gst_structure_get_string ((GstStructure *) factory->metadata, key);
}
/**
* gst_element_factory_get_metadata_keys:
* @factory: a #GstElementFactory
*
* Get the available keys for the metadata on @factory.
*
* Returns: (transfer full) (element-type utf8) (array zero-terminated=1) (nullable):
* a %NULL-terminated array of key strings, or %NULL when there is no
* metadata. Free with g_strfreev() when no longer needed.
*/
gchar **
gst_element_factory_get_metadata_keys (GstElementFactory * factory)
{
GstStructure *metadata;
gchar **arr;
gint i, num;
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
metadata = (GstStructure *) factory->metadata;
if (metadata == NULL)
return NULL;
num = gst_structure_n_fields (metadata);
if (num == 0)
return NULL;
arr = g_new (gchar *, num + 1);
for (i = 0; i < num; ++i) {
arr[i] = g_strdup (gst_structure_nth_field_name (metadata, i));
}
arr[i] = NULL;
return arr;
}
/**
* 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,
(gpointer) g_intern_string (interfacename));
}
/**
* gst_element_factory_get_static_pad_templates:
* @factory: a #GstElementFactory
*
* Gets the #GList of #GstStaticPadTemplate for this factory.
*
* Returns: (transfer none) (element-type Gst.StaticPadTemplate): the
* static pad templates
*/
const 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
*/
GstURIType
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: (transfer none) (array zero-terminated=1): the supported protocols
* or %NULL
*/
const gchar *const *
gst_element_factory_get_uri_protocols (GstElementFactory * factory)
{
g_return_val_if_fail (GST_IS_ELEMENT_FACTORY (factory), NULL);
return (const gchar * const *) 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.
*/
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;
}
typedef struct
{
GstElementFactoryListType type;
GstRank minrank;
} FilterData;
/**
* gst_element_factory_list_is_type:
* @factory: a #GstElementFactory
* @type: a #GstElementFactoryListType
*
* Check if @factory is of the given types.
*
* Returns: %TRUE if @factory is of @type.
*/
gboolean
gst_element_factory_list_is_type (GstElementFactory * factory,
GstElementFactoryListType type)
{
gboolean res = FALSE;
const gchar *klass;
klass =
gst_element_factory_get_metadata (factory, GST_ELEMENT_METADATA_KLASS);
if (klass == NULL) {
GST_ERROR_OBJECT (factory, "element factory is missing klass identifiers");
return res;
}
/* Filter by element type first, as soon as it matches
* one type, we skip all other tests */
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_SINK))
res = (strstr (klass, "Sink") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_SRC))
res = (strstr (klass, "Source") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_DECODER))
res = (strstr (klass, "Decoder") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_ENCODER))
res = (strstr (klass, "Encoder") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_MUXER))
res = (strstr (klass, "Muxer") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_DEMUXER))
res = (strstr (klass, "Demux") != NULL);
/* FIXME : We're actually parsing two Classes here... */
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_PARSER))
res = ((strstr (klass, "Parser") != NULL)
&& (strstr (klass, "Codec") != NULL));
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_DEPAYLOADER))
res = (strstr (klass, "Depayloader") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_PAYLOADER))
res = (strstr (klass, "Payloader") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_FORMATTER))
res = (strstr (klass, "Formatter") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_DECRYPTOR))
res = (strstr (klass, "Decryptor") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_ENCRYPTOR))
res = (strstr (klass, "Encryptor") != NULL);
if (!res && (type & GST_ELEMENT_FACTORY_TYPE_HARDWARE))
res = (strstr (klass, "Hardware") != NULL);
/* Filter by media type now, we only test if it
* matched any of the types above or only checking the media
* type was requested. */
if ((res || !(type & (GST_ELEMENT_FACTORY_TYPE_MAX_ELEMENTS - 1)))
&& (type & (GST_ELEMENT_FACTORY_TYPE_MEDIA_AUDIO |
GST_ELEMENT_FACTORY_TYPE_MEDIA_VIDEO |
GST_ELEMENT_FACTORY_TYPE_MEDIA_IMAGE |
GST_ELEMENT_FACTORY_TYPE_MEDIA_SUBTITLE |
GST_ELEMENT_FACTORY_TYPE_MEDIA_METADATA)))
res = ((type & GST_ELEMENT_FACTORY_TYPE_MEDIA_AUDIO)
&& (strstr (klass, "Audio") != NULL))
|| ((type & GST_ELEMENT_FACTORY_TYPE_MEDIA_VIDEO)
&& (strstr (klass, "Video") != NULL))
|| ((type & GST_ELEMENT_FACTORY_TYPE_MEDIA_IMAGE)
&& (strstr (klass, "Image") != NULL)) ||
((type & GST_ELEMENT_FACTORY_TYPE_MEDIA_SUBTITLE)
&& (strstr (klass, "Subtitle") != NULL)) ||
((type & GST_ELEMENT_FACTORY_TYPE_MEDIA_METADATA)
&& (strstr (klass, "Metadata") != NULL));
return res;
}
static gboolean
element_filter (GstPluginFeature * feature, FilterData * data)
{
gboolean res;
/* we only care about element factories */
if (G_UNLIKELY (!GST_IS_ELEMENT_FACTORY (feature)))
return FALSE;
res = (gst_plugin_feature_get_rank (feature) >= data->minrank) &&
gst_element_factory_list_is_type (GST_ELEMENT_FACTORY_CAST (feature),
data->type);
return res;
}
/**
* gst_element_factory_list_get_elements:
* @type: a #GstElementFactoryListType
* @minrank: Minimum rank
*
* Get a list of factories that match the given @type. Only elements
* with a rank greater or equal to @minrank will be returned.
* The list of factories is returned by decreasing rank.
*
* Returns: (transfer full) (element-type Gst.ElementFactory): a #GList of
* #GstElementFactory elements. Use gst_plugin_feature_list_free() after
* usage.
*/
GList *
gst_element_factory_list_get_elements (GstElementFactoryListType type,
GstRank minrank)
{
GList *result;
FilterData data;
/* prepare type */
data.type = type;
data.minrank = minrank;
/* get the feature list using the filter */
result = gst_registry_feature_filter (gst_registry_get (),
(GstPluginFeatureFilter) element_filter, FALSE, &data);
/* sort on rank and name */
result = g_list_sort (result, gst_plugin_feature_rank_compare_func);
return result;
}
/**
* gst_element_factory_list_filter:
* @list: (transfer none) (element-type Gst.ElementFactory): a #GList of
* #GstElementFactory to filter
* @caps: a #GstCaps
* @direction: a #GstPadDirection to filter on
* @subsetonly: whether to filter on caps subsets or not.
*
* Filter out all the elementfactories in @list that can handle @caps in
* the given direction.
*
* If @subsetonly is %TRUE, then only the elements whose pads templates
* are a complete superset of @caps will be returned. Else any element
* whose pad templates caps can intersect with @caps will be returned.
*
* Returns: (transfer full) (element-type Gst.ElementFactory): a #GList of
* #GstElementFactory elements that match the given requisites.
* Use #gst_plugin_feature_list_free after usage.
*/
GList *
gst_element_factory_list_filter (GList * list,
const GstCaps * caps, GstPadDirection direction, gboolean subsetonly)
{
GQueue results = G_QUEUE_INIT;
GST_DEBUG ("finding factories");
/* loop over all the factories */
for (; list; list = list->next) {
GstElementFactory *factory;
const GList *templates;
GList *walk;
factory = (GstElementFactory *) list->data;
GST_DEBUG ("Trying %s",
gst_plugin_feature_get_name ((GstPluginFeature *) factory));
/* get the templates from the element factory */
templates = gst_element_factory_get_static_pad_templates (factory);
for (walk = (GList *) templates; walk; walk = g_list_next (walk)) {
GstStaticPadTemplate *templ = walk->data;
/* we only care about the sink templates */
if (templ->direction == direction) {
GstCaps *tmpl_caps;
/* try to intersect the caps with the caps of the template */
tmpl_caps = gst_static_caps_get (&templ->static_caps);
/* FIXME, intersect is not the right method, we ideally want to check
* for a subset here */
/* check if the intersection is empty */
if ((subsetonly && gst_caps_is_subset (caps, tmpl_caps)) ||
(!subsetonly && gst_caps_can_intersect (caps, tmpl_caps))) {
/* non empty intersection, we can use this element */
g_queue_push_tail (&results, gst_object_ref (factory));
gst_caps_unref (tmpl_caps);
break;
}
gst_caps_unref (tmpl_caps);
}
}
}
return results.head;
}