mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2024-12-28 11:10:37 +00:00
Code Issues 1 Projects Releases Wiki Activity
gstreamer/gst/gstelement.c
Edward Hervey 04ebbc9f5a GstElement: Add a more flexible way to get request pads. 
The new request_new_pad_full vmethod provides an additional caps field,
which allows elements to take better decision process.

Also, add a gst_element_request_pad() function to allow developers to be
able to specify which pad template they want a pad of.

Convert gstutils to use that new method instead of the old one when more
efficient.

This is useful for being able to request pads in a more flexible way,
especially when the element can provide pads whose caps depend on
runtime configuration and therefore can't provide pre-registered
pad templates.

API: GstElement::request_new_pad_full
API: gst_element_request_pad

https://bugzilla.gnome.org/show_bug.cgi?id=637300
2011-01-05 19:46:47 +01:00

3233 lines
94 KiB
C
Raw Blame History

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2004 Wim Taymans <wim@fluendo.com>
*
* gstelement.c: The base element, all elements derive from this
*
* 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:gstelement
* @short_description: Abstract base class for all pipeline elements
* @see_also: #GstElementFactory, #GstPad
*
* GstElement is the abstract base class needed to construct an element that
* can be used in a GStreamer pipeline. Please refer to the plugin writers
* guide for more information on creating #GstElement subclasses.
*
* The name of a #GstElement can be get with gst_element_get_name() and set with
* gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
* core when using the appropriate locking. Do not use this in plug-ins or
* applications in order to retain ABI compatibility.
*
* All elements have pads (of the type #GstPad). These pads link to pads on
* other elements. #GstBuffer flow between these linked pads.
* A #GstElement has a #GList of #GstPad structures for all their input (or sink)
* and output (or source) pads.
* Core and plug-in writers can add and remove pads with gst_element_add_pad()
* and gst_element_remove_pad().
*
* A pad of an element can be retrieved by name with gst_element_get_pad().
* An iterator of all pads can be retrieved with gst_element_iterate_pads().
*
* Elements can be linked through their pads.
* If the link is straightforward, use the gst_element_link()
* convenience function to link two elements, or gst_element_link_many()
* for more elements in a row.
* Use gst_element_link_filtered() to link two elements constrained by
* a specified set of #GstCaps.
* For finer control, use gst_element_link_pads() and
* gst_element_link_pads_filtered() to specify the pads to link on
* each element by name.
*
* Each element has a state (see #GstState). You can get and set the state
* of an element with gst_element_get_state() and gst_element_set_state().
* Setting a state triggers a #GstStateChange. To get a string representation
* of a #GstState, use gst_element_state_get_name().
*
* You can get and set a #GstClock on an element using gst_element_get_clock()
* and gst_element_set_clock().
* Some elements can provide a clock for the pipeline if
* gst_element_provides_clock() returns %TRUE. With the
* gst_element_provide_clock() method one can retrieve the clock provided by
* such an element.
* Not all elements require a clock to operate correctly. If
* gst_element_requires_clock() returns %TRUE, a clock should be set on the
* element with gst_element_set_clock().
*
* Note that clock slection and distribution is normally handled by the
* toplevel #GstPipeline so the clock functions are only to be used in very
* specific situations.
*
* Last reviewed on 2009-05-29 (0.10.24)
*/
#include "gst_private.h"
#include <glib.h>
#include <stdarg.h>
#include <gobject/gvaluecollector.h>
#include "gstelement.h"
#include "gstelementdetails.h"
#include "gstenumtypes.h"
#include "gstbus.h"
#include "gstmarshal.h"
#include "gsterror.h"
#include "gstevent.h"
#include "gstutils.h"
#include "gstinfo.h"
#include "gstvalue.h"
#include "gst-i18n-lib.h"
/* Element signals and args */
enum
{
PAD_ADDED,
PAD_REMOVED,
NO_MORE_PADS,
/* add more above */
LAST_SIGNAL
};
enum
{
ARG_0
/* FILL ME */
};
#ifdef GST_DISABLE_DEPRECATED
#if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
#include <libxml/parser.h>
xmlNodePtr gst_object_save_thyself (const GstObject * object,
xmlNodePtr parent);
GstObject *gst_object_load_thyself (xmlNodePtr parent);
void gst_pad_load_and_link (xmlNodePtr self, GstObject * parent);
#endif
#endif
static void gst_element_class_init (GstElementClass * klass);
static void gst_element_init (GstElement * element);
static void gst_element_base_class_init (gpointer g_class);
static void gst_element_base_class_finalize (gpointer g_class);
static void gst_element_dispose (GObject * object);
static void gst_element_finalize (GObject * object);
static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
GstStateChange transition);
static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
GstState * state, GstState * pending, GstClockTime timeout);
static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
GstState state);
static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
static gboolean gst_element_default_send_event (GstElement * element,
GstEvent * event);
static gboolean gst_element_default_query (GstElement * element,
GstQuery * query);
static GstPadTemplate
* gst_element_class_get_request_pad_template (GstElementClass *
element_class, const gchar * name);
#if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
static xmlNodePtr gst_element_save_thyself (GstObject * object,
xmlNodePtr parent);
static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
#endif
static GstObjectClass *parent_class = NULL;
static guint gst_element_signals[LAST_SIGNAL] = { 0 };
/* this is used in gstelementfactory.c:gst_element_register() */
GQuark _gst_elementclass_factory = 0;
GType
gst_element_get_type (void)
{
static volatile gsize gst_element_type = 0;
if (g_once_init_enter (&gst_element_type)) {
GType _type;
static const GTypeInfo element_info = {
sizeof (GstElementClass),
gst_element_base_class_init,
gst_element_base_class_finalize,
(GClassInitFunc) gst_element_class_init,
NULL,
NULL,
sizeof (GstElement),
0,
(GInstanceInitFunc) gst_element_init,
NULL
};
_type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
&element_info, G_TYPE_FLAG_ABSTRACT);
_gst_elementclass_factory =
g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
g_once_init_leave (&gst_element_type, _type);
}
return gst_element_type;
}
static void
gst_element_class_init (GstElementClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
parent_class = g_type_class_peek_parent (klass);
/**
* GstElement::pad-added:
* @gstelement: the object which received the signal
* @new_pad: the pad that has been added
*
* a new #GstPad has been added to the element.
*/
gst_element_signals[PAD_ADDED] =
g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
/**
* GstElement::pad-removed:
* @gstelement: the object which received the signal
* @old_pad: the pad that has been removed
*
* a #GstPad has been removed from the element
*/
gst_element_signals[PAD_REMOVED] =
g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
/**
* GstElement::no-more-pads:
* @gstelement: the object which received the signal
*
* This signals that the element will not generate more dynamic pads.
*/
gst_element_signals[NO_MORE_PADS] =
g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
gobject_class->dispose = gst_element_dispose;
gobject_class->finalize = gst_element_finalize;
#if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
gstobject_class->save_thyself =
((gpointer (*)(GstObject * object,
gpointer self)) * GST_DEBUG_FUNCPTR (gst_element_save_thyself));
gstobject_class->restore_thyself =
((void (*)(GstObject * object,
gpointer self)) *GST_DEBUG_FUNCPTR (gst_element_restore_thyself));
#endif
klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
klass->numpadtemplates = 0;
klass->elementfactory = NULL;
}
static void
gst_element_base_class_init (gpointer g_class)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
/* FIXME 0.11: Copy the element details and instead of clearing the
* pad template list copy the list and increase the refcount of
* the pad templates by one.
*
* This will make it possible to add pad templates and set element
* details in the class_init functions and is the real GObject way
* of doing things.
* See http://bugzilla.gnome.org/show_bug.cgi?id=491501
*/
memset (&element_class->details, 0, sizeof (GstElementDetails));
element_class->meta_data = NULL;
element_class->padtemplates = NULL;
/* set the factory, see gst_element_register() */
element_class->elementfactory =
g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
_gst_elementclass_factory);
GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
element_class->elementfactory);
}
static void
gst_element_base_class_finalize (gpointer g_class)
{
GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
g_list_free (klass->padtemplates);
__gst_element_details_clear (&klass->details);
if (klass->meta_data) {
gst_structure_free (klass->meta_data);
klass->meta_data = NULL;
}
}
static void
gst_element_init (GstElement * element)
{
GST_STATE (element) = GST_STATE_NULL;
GST_STATE_TARGET (element) = GST_STATE_NULL;
GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
/* FIXME 0.11: Store this directly in the instance struct */
element->state_lock = g_slice_new (GStaticRecMutex);
g_static_rec_mutex_init (element->state_lock);
element->state_cond = g_cond_new ();
}
/**
* gst_element_release_request_pad:
* @element: a #GstElement to release the request pad of.
* @pad: the #GstPad to release.
*
* Makes the element free the previously requested pad as obtained
* with gst_element_get_request_pad().
*
* This does not unref the pad. If the pad was created by using
* gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
* followed by gst_object_unref() to free the @pad.
*
* MT safe.
*/
void
gst_element_release_request_pad (GstElement * element, GstPad * pad)
{
GstElementClass *oclass;
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (GST_IS_PAD (pad));
oclass = GST_ELEMENT_GET_CLASS (element);
/* if the element implements a custom release function we call that, else we
* simply remove the pad from the element */
if (oclass->release_pad)
(oclass->release_pad) (element, pad);
else
gst_element_remove_pad (element, pad);
}
/**
* gst_element_requires_clock:
* @element: a #GstElement to query
*
* Query if the element requires a clock.
*
* Returns: %TRUE if the element requires a clock
*
* MT safe.
*/
gboolean
gst_element_requires_clock (GstElement * element)
{
gboolean result;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
return result;
}
/**
* gst_element_provides_clock:
* @element: a #GstElement to query
*
* Query if the element provides a clock. A #GstClock provided by an
* element can be used as the global #GstClock for the pipeline.
* An element that can provide a clock is only required to do so in the PAUSED
* state, this means when it is fully negotiated and has allocated the resources
* to operate the clock.
*
* Returns: %TRUE if the element provides a clock
*
* MT safe.
*/
gboolean
gst_element_provides_clock (GstElement * element)
{
gboolean result;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
return result;
}
/**
* gst_element_provide_clock:
* @element: a #GstElement to query
*
* Get the clock provided by the given element.
* <note>An element is only required to provide a clock in the PAUSED
* state. Some elements can provide a clock in other states.</note>
*
* Returns: (transfer full): the GstClock provided by the element or %NULL
* if no clock could be provided. Unref after usage.
*
* MT safe.
*/
GstClock *
gst_element_provide_clock (GstElement * element)
{
GstClock *result = NULL;
GstElementClass *oclass;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->provide_clock)
result = oclass->provide_clock (element);
return result;
}
/**
* gst_element_set_clock:
* @element: a #GstElement to set the clock for.
* @clock: the #GstClock to set for the element.
*
* Sets the clock for the element. This function increases the
* refcount on the clock. Any previously set clock on the object
* is unreffed.
*
* Returns: %TRUE if the element accepted the clock. An element can refuse a
* clock when it, for example, is not able to slave its internal clock to the
* @clock or when it requires a specific clock to operate.
*
* MT safe.
*/
gboolean
gst_element_set_clock (GstElement * element, GstClock * clock)
{
GstElementClass *oclass;
gboolean res = TRUE;
GstClock **clock_p;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
oclass = GST_ELEMENT_GET_CLASS (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
if (oclass->set_clock)
res = oclass->set_clock (element, clock);
if (res) {
/* only update the clock pointer if the element accepted the clock */
GST_OBJECT_LOCK (element);
clock_p = &element->clock;
gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
GST_OBJECT_UNLOCK (element);
}
return res;
}
/**
* gst_element_get_clock:
* @element: a #GstElement to get the clock of.
*
* Gets the currently configured clock of the element. This is the clock as was
* last set with gst_element_set_clock().
*
* Returns: (transfer full): the #GstClock of the element. unref after usage.
*
* MT safe.
*/
GstClock *
gst_element_get_clock (GstElement * element)
{
GstClock *result;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
GST_OBJECT_LOCK (element);
if ((result = element->clock))
gst_object_ref (result);
GST_OBJECT_UNLOCK (element);
return result;
}
/**
* gst_element_set_base_time:
* @element: a #GstElement.
* @time: the base time to set.
*
* Set the base time of an element. See gst_element_get_base_time().
*
* MT safe.
*/
void
gst_element_set_base_time (GstElement * element, GstClockTime time)
{
GstClockTime old;
g_return_if_fail (GST_IS_ELEMENT (element));
GST_OBJECT_LOCK (element);
old = element->base_time;
element->base_time = time;
GST_OBJECT_UNLOCK (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
"set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
GST_TIME_ARGS (time), GST_TIME_ARGS (old));
}
/**
* gst_element_get_base_time:
* @element: a #GstElement.
*
* Returns the base time of the element. The base time is the
* absolute time of the clock when this element was last put to
* PLAYING. Subtracting the base time from the clock time gives
* the running time of the element.
*
* Returns: the base time of the element.
*
* MT safe.
*/
GstClockTime
gst_element_get_base_time (GstElement * element)
{
GstClockTime result;
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
GST_OBJECT_LOCK (element);
result = element->base_time;
GST_OBJECT_UNLOCK (element);
return result;
}
/**
* gst_element_set_start_time:
* @element: a #GstElement.
* @time: the base time to set.
*
* Set the start time of an element. The start time of the element is the
* running time of the element when it last went to the PAUSED state. In READY
* or after a flushing seek, it is set to 0.
*
* Toplevel elements like #GstPipeline will manage the start_time and
* base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
* on such a toplevel element will disable the distribution of the base_time to
* the children and can be useful if the application manages the base_time
* itself, for example if you want to synchronize capture from multiple
* pipelines, and you can also ensure that the pipelines have the same clock.
*
* MT safe.
*
* Since: 0.10.24
*/
void
gst_element_set_start_time (GstElement * element, GstClockTime time)
{
GstClockTime old;
g_return_if_fail (GST_IS_ELEMENT (element));
GST_OBJECT_LOCK (element);
old = GST_ELEMENT_START_TIME (element);
GST_ELEMENT_START_TIME (element) = time;
GST_OBJECT_UNLOCK (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
"set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
GST_TIME_ARGS (time), GST_TIME_ARGS (old));
}
/**
* gst_element_get_start_time:
* @element: a #GstElement.
*
* Returns the start time of the element. The start time is the
* running time of the clock when this element was last put to PAUSED.
*
* Usually the start_time is managed by a toplevel element such as
* #GstPipeline.
*
* MT safe.
*
* Returns: the start time of the element.
*
* Since: 0.10.24
*/
GstClockTime
gst_element_get_start_time (GstElement * element)
{
GstClockTime result;
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
GST_OBJECT_LOCK (element);
result = GST_ELEMENT_START_TIME (element);
GST_OBJECT_UNLOCK (element);
return result;
}
/**
* gst_element_is_indexable:
* @element: a #GstElement.
*
* Queries if the element can be indexed.
*
* Returns: TRUE if the element can be indexed.
*
* MT safe.
*/
gboolean
gst_element_is_indexable (GstElement * element)
{
gboolean result;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
return result;
}
/**
* gst_element_set_index:
* @element: a #GstElement.
* @index: (transfer none): a #GstIndex.
*
* Set @index on the element. The refcount of the index
* will be increased, any previously set index is unreffed.
*
* MT safe.
*/
void
gst_element_set_index (GstElement * element, GstIndex * index)
{
GstElementClass *oclass;
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (index == NULL || GST_IS_INDEX (index));
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->set_index)
oclass->set_index (element, index);
}
/**
* gst_element_get_index:
* @element: a #GstElement.
*
* Gets the index from the element.
*
* Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
* element. unref after usage.
*
* MT safe.
*/
GstIndex *
gst_element_get_index (GstElement * element)
{
GstElementClass *oclass;
GstIndex *result = NULL;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->get_index)
result = oclass->get_index (element);
return result;
}
/**
* gst_element_add_pad:
* @element: a #GstElement to add the pad to.
* @pad: (transfer full): the #GstPad to add to the element.
*
* Adds a pad (link point) to @element. @pad's parent will be set to @element;
* see gst_object_set_parent() for refcounting information.
*
* Pads are not automatically activated so elements should perform the needed
* steps to activate the pad in case this pad is added in the PAUSED or PLAYING
* state. See gst_pad_set_active() for more information about activating pads.
*
* The pad and the element should be unlocked when calling this function.
*
* This function will emit the #GstElement::pad-added signal on the element.
*
* Returns: %TRUE if the pad could be added. This function can fail when
* a pad with the same name already existed or the pad already had another
* parent.
*
* MT safe.
*/
gboolean
gst_element_add_pad (GstElement * element, GstPad * pad)
{
gchar *pad_name;
gboolean flushing;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
/* locking pad to look at the name */
GST_OBJECT_LOCK (pad);
pad_name = g_strdup (GST_PAD_NAME (pad));
GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
GST_STR_NULL (pad_name));
flushing = GST_PAD_IS_FLUSHING (pad);
GST_OBJECT_UNLOCK (pad);
/* then check to see if there's already a pad by that name here */
GST_OBJECT_LOCK (element);
if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
goto name_exists;
/* try to set the pad's parent */
if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
GST_OBJECT_CAST (element))))
goto had_parent;
/* check for flushing pads */
if (flushing && (GST_STATE (element) > GST_STATE_READY ||
GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
g_warning ("adding flushing pad '%s' to running element '%s', you need to "
"use gst_pad_set_active(pad,TRUE) before adding it.",
GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
/* unset flushing */
GST_OBJECT_LOCK (pad);
GST_PAD_UNSET_FLUSHING (pad);
GST_OBJECT_UNLOCK (pad);
}
g_free (pad_name);
/* add it to the list */
switch (gst_pad_get_direction (pad)) {
case GST_PAD_SRC:
element->srcpads = g_list_prepend (element->srcpads, pad);
element->numsrcpads++;
break;
case GST_PAD_SINK:
element->sinkpads = g_list_prepend (element->sinkpads, pad);
element->numsinkpads++;
break;
default:
goto no_direction;
}
element->pads = g_list_prepend (element->pads, pad);
element->numpads++;
element->pads_cookie++;
GST_OBJECT_UNLOCK (element);
/* emit the PAD_ADDED signal */
g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
return TRUE;
/* ERROR cases */
name_exists:
{
g_critical ("Padname %s is not unique in element %s, not adding",
pad_name, GST_ELEMENT_NAME (element));
GST_OBJECT_UNLOCK (element);
g_free (pad_name);
return FALSE;
}
had_parent:
{
g_critical
("Pad %s already has parent when trying to add to element %s",
pad_name, GST_ELEMENT_NAME (element));
GST_OBJECT_UNLOCK (element);
g_free (pad_name);
return FALSE;
}
no_direction:
{
GST_OBJECT_LOCK (pad);
g_critical
("Trying to add pad %s to element %s, but it has no direction",
GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
GST_OBJECT_UNLOCK (pad);
GST_OBJECT_UNLOCK (element);
return FALSE;
}
}
/**
* gst_element_remove_pad:
* @element: a #GstElement to remove pad from.
* @pad: (transfer none): the #GstPad to remove from the element.
*
* Removes @pad from @element. @pad will be destroyed if it has not been
* referenced elsewhere using gst_object_unparent().
*
* This function is used by plugin developers and should not be used
* by applications. Pads that were dynamically requested from elements
* with gst_element_get_request_pad() should be released with the
* gst_element_release_request_pad() function instead.
*
* Pads are not automatically deactivated so elements should perform the needed
* steps to deactivate the pad in case this pad is removed in the PAUSED or
* PLAYING state. See gst_pad_set_active() for more information about
* deactivating pads.
*
* The pad and the element should be unlocked when calling this function.
*
* This function will emit the #GstElement::pad-removed signal on the element.
*
* Returns: %TRUE if the pad could be removed. Can return %FALSE if the
* pad does not belong to the provided element.
*
* MT safe.
*/
gboolean
gst_element_remove_pad (GstElement * element, GstPad * pad)
{
GstPad *peer;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
/* locking pad to look at the name and parent */
GST_OBJECT_LOCK (pad);
GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
GST_STR_NULL (GST_PAD_NAME (pad)));
if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
goto not_our_pad;
GST_OBJECT_UNLOCK (pad);
/* unlink */
if ((peer = gst_pad_get_peer (pad))) {
/* window for MT unsafeness, someone else could unlink here
* and then we call unlink with wrong pads. The unlink
* function would catch this and safely return failed. */
if (GST_PAD_IS_SRC (pad))
gst_pad_unlink (pad, peer);
else
gst_pad_unlink (peer, pad);
gst_object_unref (peer);
}
GST_OBJECT_LOCK (element);
/* remove it from the list */
switch (gst_pad_get_direction (pad)) {
case GST_PAD_SRC:
element->srcpads = g_list_remove (element->srcpads, pad);
element->numsrcpads--;
break;
case GST_PAD_SINK:
element->sinkpads = g_list_remove (element->sinkpads, pad);
element->numsinkpads--;
break;
default:
g_critical ("Removing pad without direction???");
break;
}
element->pads = g_list_remove (element->pads, pad);
element->numpads--;
element->pads_cookie++;
GST_OBJECT_UNLOCK (element);
/* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
gst_object_unparent (GST_OBJECT_CAST (pad));
return TRUE;
/* ERRORS */
not_our_pad:
{
/* FIXME, locking order? */
GST_OBJECT_LOCK (element);
g_critical ("Padname %s:%s does not belong to element %s when removing",
GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
GST_OBJECT_UNLOCK (element);
GST_OBJECT_UNLOCK (pad);
return FALSE;
}
}
/**
* gst_element_no_more_pads:
* @element: a #GstElement
*
* Use this function to signal that the element does not expect any more pads
* to show up in the current pipeline. This function should be called whenever
* pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
* pad templates use this in combination with autopluggers to figure out that
* the element is done initializing its pads.
*
* This function emits the #GstElement::no-more-pads signal.
*
* MT safe.
*/
void
gst_element_no_more_pads (GstElement * element)
{
g_return_if_fail (GST_IS_ELEMENT (element));
g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
}
static gint
pad_compare_name (GstPad * pad1, const gchar * name)
{
gint result;
GST_OBJECT_LOCK (pad1);
result = strcmp (GST_PAD_NAME (pad1), name);
GST_OBJECT_UNLOCK (pad1);
return result;
}
/**
* gst_element_get_static_pad:
* @element: a #GstElement to find a static pad of.
* @name: the name of the static #GstPad to retrieve.
*
* Retrieves a pad from @element by name. This version only retrieves
* already-existing (i.e. 'static') pads.
*
* Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
* unref after usage.
*
* MT safe.
*/
GstPad *
gst_element_get_static_pad (GstElement * element, const gchar * name)
{
GList *find;
GstPad *result = NULL;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
GST_OBJECT_LOCK (element);
find =
g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
if (find) {
result = GST_PAD_CAST (find->data);
gst_object_ref (result);
}
if (result == NULL) {
GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
name, GST_ELEMENT_NAME (element));
} else {
GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
GST_ELEMENT_NAME (element), name);
}
GST_OBJECT_UNLOCK (element);
return result;
}
static GstPad *
_gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
const gchar * name, const GstCaps * caps)
{
GstPad *newpad = NULL;
GstElementClass *oclass;
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->request_new_pad_full)
newpad = (oclass->request_new_pad_full) (element, templ, name, caps);
else if (oclass->request_new_pad)
newpad = (oclass->request_new_pad) (element, templ, name);
if (newpad)
gst_object_ref (newpad);
return newpad;
}
/**
* gst_element_get_request_pad:
* @element: a #GstElement to find a request pad of.
* @name: the name of the request #GstPad to retrieve.
*
* Retrieves a pad from the element by name. This version only retrieves
* request pads. The pad should be released with
* gst_element_release_request_pad().
*
* This method is slow and will be deprecated in the future. New code should
* use gst_element_request_pad() with the requested template.
*
* Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
* Release after usage.
*/
GstPad *
gst_element_get_request_pad (GstElement * element, const gchar * name)
{
GstPadTemplate *templ = NULL;
GstPad *pad;
const gchar *req_name = NULL;
gboolean templ_found = FALSE;
GList *list;
const gchar *data;
gchar *str, *endptr = NULL;
GstElementClass *class;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
class = GST_ELEMENT_GET_CLASS (element);
/* if the name contains a %, we assume it's the complete template name. Get
* the template and try to get a pad */
if (strstr (name, "%")) {
templ = gst_element_class_get_request_pad_template (class, name);
req_name = NULL;
if (templ)
templ_found = TRUE;
} else {
/* there is no % in the name, try to find a matching template */
list = class->padtemplates;
while (!templ_found && list) {
templ = (GstPadTemplate *) list->data;
if (templ->presence == GST_PAD_REQUEST) {
GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
templ->name_template);
/* see if we find an exact match */
if (strcmp (name, templ->name_template) == 0) {
templ_found = TRUE;
req_name = name;
break;
}
/* Because of sanity checks in gst_pad_template_new(), we know that %s
and %d, occurring at the end of the name_template, are the only
possibilities. */
else if ((str = strchr (templ->name_template, '%'))
&& strncmp (templ->name_template, name,
str - templ->name_template) == 0
&& strlen (name) > str - templ->name_template) {
data = name + (str - templ->name_template);
if (*(str + 1) == 'd') {
gint tmp;
/* it's an int */
tmp = strtol (data, &endptr, 10);
if (endptr && *endptr == '\0') {
templ_found = TRUE;
req_name = name;
break;
}
} else {
/* it's a string */
templ_found = TRUE;
req_name = name;
break;
}
}
}
list = list->next;
}
}
if (!templ_found)
return NULL;
pad = _gst_element_request_pad (element, templ, req_name, NULL);
return pad;
}
/**
* gst_element_request_pad:
* @element: a #GstElement to find a request pad of.
* @templ: a #GstPadTemplate of which we want a pad of.
* @name: (transfer none) (allow-none): the name of the request #GstPad
* to retrieve. Can be %NULL.
* @caps: (transfer none) (allow-none): the caps of the pad we want to
* request. Can be %NULL.
*
* Retrieves a request pad from the element according to the provided template.
*
* If the @caps are specified and the element implements thew new
* request_new_pad_full virtual method, the element will use them to select
* which pad to create.
*
* The pad should be released with gst_element_release_request_pad().
*
* Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
* Release after usage.
*
* Since: 0.10.32
*/
GstPad *
gst_element_request_pad (GstElement * element,
GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (templ != NULL, NULL);
return _gst_element_request_pad (element, templ, name, caps);
}
/**
* gst_element_get_pad:
* @element: a #GstElement.
* @name: the name of the pad to retrieve.
*
* Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
* first, then gst_element_get_request_pad().
*
* Deprecated: This function is deprecated as it's unclear if the reference
* to the result pad should be released with gst_object_unref() in case of a static pad
* or gst_element_release_request_pad() in case of a request pad.
* Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
*
* Returns: (transfer full): the #GstPad if found, otherwise %NULL. Unref or Release after usage,
* depending on the type of the pad.
*/
#ifndef GST_REMOVE_DEPRECATED
#ifdef GST_DISABLE_DEPRECATED
GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
#endif
GstPad *
gst_element_get_pad (GstElement * element, const gchar * name)
{
GstPad *pad;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
pad = gst_element_get_static_pad (element, name);
if (!pad)
pad = gst_element_get_request_pad (element, name);
return pad;
}
#endif /* GST_REMOVE_DEPRECATED */
static GstIteratorItem
iterate_pad (GstIterator * it, GstPad * pad)
{
gst_object_ref (pad);
return GST_ITERATOR_ITEM_PASS;
}
static GstIterator *
gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
{
GstIterator *result;
GST_OBJECT_LOCK (element);
gst_object_ref (element);
result = gst_iterator_new_list (GST_TYPE_PAD,
GST_OBJECT_GET_LOCK (element),
&element->pads_cookie,
padlist,
element,
(GstIteratorItemFunction) iterate_pad,
(GstIteratorDisposeFunction) gst_object_unref);
GST_OBJECT_UNLOCK (element);
return result;
}
/**
* gst_element_iterate_pads:
* @element: a #GstElement to iterate pads of.
*
* Retrieves an iterattor of @element's pads. The iterator should
* be freed after usage.
*
* Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
* after use.
*
* MT safe.
*/
GstIterator *
gst_element_iterate_pads (GstElement * element)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return gst_element_iterate_pad_list (element, &element->pads);
}
/**
* gst_element_iterate_src_pads:
* @element: a #GstElement.
*
* Retrieves an iterator of @element's source pads.
*
* Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
* after use.
*
* MT safe.
*/
GstIterator *
gst_element_iterate_src_pads (GstElement * element)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return gst_element_iterate_pad_list (element, &element->srcpads);
}
/**
* gst_element_iterate_sink_pads:
* @element: a #GstElement.
*
* Retrieves an iterator of @element's sink pads.
*
* Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
* after use.
*
* MT safe.
*/
GstIterator *
gst_element_iterate_sink_pads (GstElement * element)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return gst_element_iterate_pad_list (element, &element->sinkpads);
}
/**
* gst_element_class_add_pad_template:
* @klass: the #GstElementClass to add the pad template to.
* @templ: (transfer none): a #GstPadTemplate to add to the element class.
*
* Adds a padtemplate to an element class. This is mainly used in the _base_init
* functions of classes.
*/
void
gst_element_class_add_pad_template (GstElementClass * klass,
GstPadTemplate * templ)
{
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
/* FIXME 0.11: allow replacing the pad templates by
* calling this with the same name as an already existing pad
* template. For this we _must_ _not_ ref the added pad template
* a second time and _must_ document that this function takes
* ownership of the pad template. Otherwise we will leak pad templates
* or the caller unref's the pad template and it disappears */
/* avoid registering pad templates with the same name */
g_return_if_fail (gst_element_class_get_pad_template (klass,
templ->name_template) == NULL);
klass->padtemplates = g_list_append (klass->padtemplates,
gst_object_ref (templ));
klass->numpadtemplates++;
}
static void
gst_element_class_add_meta_data (GstElementClass * klass,
const gchar * key, const gchar * value)
{
if (!klass->meta_data) {
/* FIXME: use a quark for "metadata" */
klass->meta_data = gst_structure_empty_new ("metadata");
}
gst_structure_set ((GstStructure *) klass->meta_data,
key, G_TYPE_STRING, value, NULL);
}
/**
* gst_element_class_set_documentation_uri:
* @klass: class to set details for
* @uri: uri of element documentation
*
* Set uri pointing to user documentation. Applications can use this to show
* help for e.g. effects to users.
*
* Since: 0.10.31
*/
void
gst_element_class_set_documentation_uri (GstElementClass * klass,
const gchar * uri)
{
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
gst_element_class_add_meta_data (klass, "doc-uri", uri);
}
/**
* gst_element_class_set_icon_name:
* @klass: class to set details for
* @name: name of an icon
*
* Elements that bridge to certain other products can include an icon of that
* used product. Application can show the icon in menus/selectors to help
* identifying specific elements.
*
* Since: 0.10.31
*/
void
gst_element_class_set_icon_name (GstElementClass * klass, const gchar * name)
{
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
gst_element_class_add_meta_data (klass, "icon-name", name);
}
/* FIXME-0.11: deprecate and remove gst_element_class_set_details*() */
/**
* gst_element_class_set_details:
* @klass: class to set details for
* @details: details to set
*
* Sets the detailed information for a #GstElementClass.
* <note>This function is for use in _base_init functions only.</note>
*
* The @details are copied.
*
* Deprecated: Use gst_element_class_set_details_simple() instead.
*/
#ifndef GST_REMOVE_DEPRECATED
#ifdef GST_DISABLE_DEPRECATED
void
gst_element_class_set_details (GstElementClass * klass,
const GstElementDetails * details);
#endif
void
gst_element_class_set_details (GstElementClass * klass,
const GstElementDetails * details)
{
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
__gst_element_details_copy (&klass->details, details);
}
#endif
/**
* gst_element_class_set_details_simple:
* @klass: class to set details for
* @longname: The long English name of the element. E.g. "File Sink"
* @classification: String describing the type of element, as an unordered list
* separated with slashes ('/'). See draft-klass.txt of the design docs
* for more details and common types. E.g: "Sink/File"
* @description: Sentence describing the purpose of the element.
* E.g: "Write stream to a file"
* @author: Name and contact details of the author(s). Use \n to separate
* multiple author details. E.g: "Joe Bloggs &lt;joe.blogs at foo.com&gt;"
*
* Sets the detailed information for a #GstElementClass. Simpler version of
* gst_element_class_set_details() that generates less linker overhead.
* <note>This function is for use in _base_init functions only.</note>
*
* The detail parameter strings are copied into the #GstElementDetails for
* the element class.
*
* Since: 0.10.14
*/
void
gst_element_class_set_details_simple (GstElementClass * klass,
const gchar * longname, const gchar * classification,
const gchar * description, const gchar * author)
{
const GstElementDetails details =
GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
(gchar *) description, (gchar *) author);
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
__gst_element_details_copy (&klass->details, &details);
}
/**
* gst_element_class_get_pad_template_list:
* @element_class: a #GstElementClass to get pad templates of.
*
* Retrieves a list of the pad templates associated with @element_class. The
* list must not be modified by the calling code.
* <note>If you use this function in the #GInstanceInitFunc of an object class
* that has subclasses, make sure to pass the g_class parameter of the
* #GInstanceInitFunc here.</note>
*
* Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
* pad templates.
*/
GList *
gst_element_class_get_pad_template_list (GstElementClass * element_class)
{
g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
return element_class->padtemplates;
}
/**
* gst_element_class_get_pad_template:
* @element_class: a #GstElementClass to get the pad template of.
* @name: the name of the #GstPadTemplate to get.
*
* Retrieves a padtemplate from @element_class with the given name.
* <note>If you use this function in the #GInstanceInitFunc of an object class
* that has subclasses, make sure to pass the g_class parameter of the
* #GInstanceInitFunc here.</note>
*
* Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
* if none was found. No unreferencing is necessary.
*/
GstPadTemplate *
gst_element_class_get_pad_template (GstElementClass * element_class,
const gchar * name)
{
GList *padlist;
g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
g_return_val_if_fail (name != NULL, NULL);
padlist = element_class->padtemplates;
while (padlist) {
GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
if (strcmp (padtempl->name_template, name) == 0)
return padtempl;
padlist = g_list_next (padlist);
}
return NULL;
}
static GstPadTemplate *
gst_element_class_get_request_pad_template (GstElementClass * element_class,
const gchar * name)
{
GstPadTemplate *tmpl;
tmpl = gst_element_class_get_pad_template (element_class, name);
if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
return tmpl;
return NULL;
}
/* get a random pad on element of the given direction.
* The pad is random in a sense that it is the first pad that is (optionaly) linked.
*/
static GstPad *
gst_element_get_random_pad (GstElement * element, gboolean need_linked,
GstPadDirection dir)
{
GstPad *result = NULL;
GList *pads;
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
switch (dir) {
case GST_PAD_SRC:
GST_OBJECT_LOCK (element);
pads = element->srcpads;
break;
case GST_PAD_SINK:
GST_OBJECT_LOCK (element);
pads = element->sinkpads;
break;
default:
goto wrong_direction;
}
for (; pads; pads = g_list_next (pads)) {
GstPad *pad = GST_PAD_CAST (pads->data);
GST_OBJECT_LOCK (pad);
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
GST_DEBUG_PAD_NAME (pad));
if (need_linked && !GST_PAD_IS_LINKED (pad)) {
/* if we require a linked pad, and it is not linked, continue the
* search */
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
GST_DEBUG_PAD_NAME (pad));
GST_OBJECT_UNLOCK (pad);
continue;
} else {
/* found a pad, stop search */
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
GST_DEBUG_PAD_NAME (pad));
GST_OBJECT_UNLOCK (pad);
result = pad;
break;
}
}
if (result)
gst_object_ref (result);
GST_OBJECT_UNLOCK (element);
return result;
/* ERROR handling */
wrong_direction:
{
g_warning ("unknown pad direction %d", dir);
return NULL;
}
}
static gboolean
gst_element_default_send_event (GstElement * element, GstEvent * event)
{
gboolean result = FALSE;
GstPad *pad;
pad = GST_EVENT_IS_DOWNSTREAM (event) ?
gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
if (pad) {
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
"pushing %s event to random %s pad %s:%s",
GST_EVENT_TYPE_NAME (event),
(GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
GST_DEBUG_PAD_NAME (pad));
result = gst_pad_push_event (pad, event);
gst_object_unref (pad);
} else {
GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
}
return result;
}
/**
* gst_element_send_event:
* @element: a #GstElement to send the event to.
* @event: (transfer full): the #GstEvent to send to the element.
*
* Sends an event to an element. If the element doesn't implement an
* event handler, the event will be pushed on a random linked sink pad for
* upstream events or a random linked source pad for downstream events.
*
* This function takes owership of the provided event so you should
* gst_event_ref() it if you want to reuse the event after this call.
*
* Returns: %TRUE if the event was handled.
*
* MT safe.
*/
gboolean
gst_element_send_event (GstElement * element, GstEvent * event)
{
GstElementClass *oclass;
gboolean result = FALSE;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (event != NULL, FALSE);
oclass = GST_ELEMENT_GET_CLASS (element);
GST_STATE_LOCK (element);
if (oclass->send_event) {
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
result = oclass->send_event (element, event);
} else {
result = gst_element_default_send_event (element, event);
}
GST_STATE_UNLOCK (element);
return result;
}
/**
* gst_element_seek:
* @element: a #GstElement to send the event to.
* @rate: The new playback rate
* @format: The format of the seek values
* @flags: The optional seek flags.
* @cur_type: The type and flags for the new current position
* @cur: The value of the new current position
* @stop_type: The type and flags for the new stop position
* @stop: The value of the new stop position
*
* Sends a seek event to an element. See gst_event_new_seek() for the details of
* the parameters. The seek event is sent to the element using
* gst_element_send_event().
*
* Returns: %TRUE if the event was handled.
*
* MT safe.
*/
gboolean
gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
GstSeekType stop_type, gint64 stop)
{
GstEvent *event;
gboolean result;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
event =
gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
result = gst_element_send_event (element, event);
return result;
}
/**
* gst_element_get_query_types:
* @element: a #GstElement to query
*
* Get an array of query types from the element.
* If the element doesn't implement a query types function,
* the query will be forwarded to the peer of a random linked sink pad.
*
* Returns: An array of #GstQueryType elements that should not
* be freed or modified.
*
* MT safe.
*/
const GstQueryType *
gst_element_get_query_types (GstElement * element)
{
GstElementClass *oclass;
const GstQueryType *result = NULL;
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->get_query_types) {
result = oclass->get_query_types (element);
} else {
GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
if (pad) {
GstPad *peer = gst_pad_get_peer (pad);
if (peer) {
result = gst_pad_get_query_types (peer);
gst_object_unref (peer);
}
gst_object_unref (pad);
}
}
return result;
}
static gboolean
gst_element_default_query (GstElement * element, GstQuery * query)
{
gboolean result = FALSE;
GstPad *pad;
pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
if (pad) {
result = gst_pad_query (pad, query);
gst_object_unref (pad);
} else {
pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
if (pad) {
GstPad *peer = gst_pad_get_peer (pad);
if (peer) {
result = gst_pad_query (peer, query);
gst_object_unref (peer);
}
gst_object_unref (pad);
}
}
return result;
}
/**
* gst_element_query:
* @element: a #GstElement to perform the query on.
* @query: (transfer none): the #GstQuery.
*
* Performs a query on the given element.
*
* For elements that don't implement a query handler, this function
* forwards the query to a random srcpad or to the peer of a
* random linked sinkpad of this element.
*
* Please note that some queries might need a running pipeline to work.
*
* Returns: TRUE if the query could be performed.
*
* MT safe.
*/
gboolean
gst_element_query (GstElement * element, GstQuery * query)
{
GstElementClass *oclass;
gboolean result = FALSE;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (query != NULL, FALSE);
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->query) {
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
GST_ELEMENT_NAME (element));
result = oclass->query (element, query);
} else {
result = gst_element_default_query (element, query);
}
return result;
}
/**
* gst_element_post_message:
* @element: a #GstElement posting the message
* @message: (transfer full): a #GstMessage to post
*
* Post a message on the element's #GstBus. This function takes ownership of the
* message; if you want to access the message after this call, you should add an
* additional reference before calling.
*
* Returns: %TRUE if the message was successfully posted. The function returns
* %FALSE if the element did not have a bus.
*
* MT safe.
*/
gboolean
gst_element_post_message (GstElement * element, GstMessage * message)
{
GstBus *bus;
gboolean result = FALSE;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (message != NULL, FALSE);
GST_OBJECT_LOCK (element);
bus = element->bus;
if (G_UNLIKELY (bus == NULL))
goto no_bus;
gst_object_ref (bus);
GST_OBJECT_UNLOCK (element);
/* we release the element lock when posting the message so that any
* (synchronous) message handlers can operate on the element */
result = gst_bus_post (bus, message);
gst_object_unref (bus);
return result;
/* ERRORS */
no_bus:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
"not posting message %p: no bus", message);
GST_OBJECT_UNLOCK (element);
gst_message_unref (message);
return FALSE;
}
}
/**
* _gst_element_error_printf:
* @format: the printf-like format to use, or %NULL
*
* This function is only used internally by the gst_element_error() macro.
*
* Returns: (transfer full): a newly allocated string, or %NULL if the format
* was %NULL or ""
*
* MT safe.
*/
gchar *
_gst_element_error_printf (const gchar * format, ...)
{
va_list args;
gchar *buffer;
if (format == NULL)
return NULL;
if (format[0] == 0)
return NULL;
va_start (args, format);
buffer = g_strdup_vprintf (format, args);
va_end (args);
return buffer;
}
/**
* gst_element_message_full:
* @element: a #GstElement to send message from
* @type: the #GstMessageType
* @domain: the GStreamer GError domain this message belongs to
* @code: the GError code belonging to the domain
* @text: (allow-none) (transfer full): an allocated text string to be used
* as a replacement for the default message connected to code,
* or %NULL
* @debug: (allow-none) (transfer full): an allocated debug message to be
* used as a replacement for the default debugging information,
* or %NULL
* @file: the source code file where the error was generated
* @function: the source code function where the error was generated
* @line: the source code line where the error was generated
*
* Post an error, warning or info message on the bus from inside an element.
*
* @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
* #GST_MESSAGE_INFO.
*
* MT safe.
*/
void gst_element_message_full
(GstElement * element, GstMessageType type,
GQuark domain, gint code, gchar * text,
gchar * debug, const gchar * file, const gchar * function, gint line)
{
GError *gerror = NULL;
gchar *name;
gchar *sent_text;
gchar *sent_debug;
gboolean has_debug = TRUE;
GstMessage *message = NULL;
/* checks */
GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
(type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
/* check if we send the given text or the default error text */
if ((text == NULL) || (text[0] == 0)) {
/* text could have come from g_strdup_printf (""); */
g_free (text);
sent_text = gst_error_get_message (domain, code);
} else
sent_text = text;
/* construct a sent_debug with extra information from source */
if ((debug == NULL) || (debug[0] == 0)) {
/* debug could have come from g_strdup_printf (""); */
has_debug = FALSE;
}
name = gst_object_get_path_string (GST_OBJECT_CAST (element));
if (has_debug)
sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
file, line, function, name, debug);
else
sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
file, line, function, name);
g_free (name);
g_free (debug);
/* create gerror and post message */
GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
sent_text);
gerror = g_error_new_literal (domain, code, sent_text);
switch (type) {
case GST_MESSAGE_ERROR:
message =
gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
break;
case GST_MESSAGE_WARNING:
message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
sent_debug);
break;
case GST_MESSAGE_INFO:
message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
sent_debug);
break;
default:
g_assert_not_reached ();
break;
}
gst_element_post_message (element, message);
GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
(type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
/* cleanup */
g_error_free (gerror);
g_free (sent_debug);
g_free (sent_text);
}
/**
* gst_element_is_locked_state:
* @element: a #GstElement.
*
* Checks if the state of an element is locked.
* If the state of an element is locked, state changes of the parent don't
* affect the element.
* This way you can leave currently unused elements inside bins. Just lock their
* state before changing the state from #GST_STATE_NULL.
*
* MT safe.
*
* Returns: TRUE, if the element's state is locked.
*/
gboolean
gst_element_is_locked_state (GstElement * element)
{
gboolean result;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
GST_OBJECT_LOCK (element);
result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
GST_OBJECT_UNLOCK (element);
return result;
}
/**
* gst_element_set_locked_state:
* @element: a #GstElement
* @locked_state: TRUE to lock the element's state
*
* Locks the state of an element, so state changes of the parent don't affect
* this element anymore.
*
* MT safe.
*
* Returns: TRUE if the state was changed, FALSE if bad parameters were given
* or the elements state-locking needed no change.
*/
gboolean
gst_element_set_locked_state (GstElement * element, gboolean locked_state)
{
gboolean old;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
GST_OBJECT_LOCK (element);
old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
if (G_UNLIKELY (old == locked_state))
goto was_ok;
if (locked_state) {
GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
GST_ELEMENT_NAME (element));
GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
} else {
GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
GST_ELEMENT_NAME (element));
GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
}
GST_OBJECT_UNLOCK (element);
return TRUE;
was_ok:
{
GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
GST_ELEMENT_NAME (element), old);
GST_OBJECT_UNLOCK (element);
return FALSE;
}
}
/**
* gst_element_sync_state_with_parent:
* @element: a #GstElement.
*
* Tries to change the state of the element to the same as its parent.
* If this function returns FALSE, the state of element is undefined.
*
* Returns: TRUE, if the element's state could be synced to the parent's state.
*
* MT safe.
*/
gboolean
gst_element_sync_state_with_parent (GstElement * element)
{
GstElement *parent;
GstState target;
GstStateChangeReturn ret;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
GstState parent_current, parent_pending;
GST_OBJECT_LOCK (parent);
parent_current = GST_STATE (parent);
parent_pending = GST_STATE_PENDING (parent);
GST_OBJECT_UNLOCK (parent);
/* set to pending if there is one, else we set it to the current state of
* the parent */
if (parent_pending != GST_STATE_VOID_PENDING)
target = parent_pending;
else
target = parent_current;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"syncing state (%s) to parent %s %s (%s, %s)",
gst_element_state_get_name (GST_STATE (element)),
GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
gst_element_state_get_name (parent_current),
gst_element_state_get_name (parent_pending));
ret = gst_element_set_state (element, target);
if (ret == GST_STATE_CHANGE_FAILURE)
goto failed;
gst_object_unref (parent);
return TRUE;
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
}
return FALSE;
/* ERROR */
failed:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"syncing state failed (%s)",
gst_element_state_change_return_get_name (ret));
gst_object_unref (parent);
return FALSE;
}
}
/* MT safe */
static GstStateChangeReturn
gst_element_get_state_func (GstElement * element,
GstState * state, GstState * pending, GstClockTime timeout)
{
GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
GstState old_pending;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
GST_OBJECT_LOCK (element);
ret = GST_STATE_RETURN (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
gst_element_state_change_return_get_name (ret));
/* we got an error, report immediately */
if (ret == GST_STATE_CHANGE_FAILURE)
goto done;
/* we got no_preroll, report immediatly */
if (ret == GST_STATE_CHANGE_NO_PREROLL)
goto done;
/* no need to wait async if we are not async */
if (ret != GST_STATE_CHANGE_ASYNC)
goto done;
old_pending = GST_STATE_PENDING (element);
if (old_pending != GST_STATE_VOID_PENDING) {
GTimeVal *timeval, abstimeout;
guint32 cookie;
if (timeout != GST_CLOCK_TIME_NONE) {
glong add = timeout / 1000;
if (add == 0)
goto done;
/* make timeout absolute */
g_get_current_time (&abstimeout);
g_time_val_add (&abstimeout, add);
timeval = &abstimeout;
} else {
timeval = NULL;
}
/* get cookie to detect state changes during waiting */
cookie = element->state_cookie;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"waiting for element to commit state");
/* we have a pending state change, wait for it to complete */
if (!GST_STATE_TIMED_WAIT (element, timeval)) {
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
/* timeout triggered */
ret = GST_STATE_CHANGE_ASYNC;
} else {
if (cookie != element->state_cookie)
goto interrupted;
/* could be success or failure */
if (old_pending == GST_STATE (element)) {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
ret = GST_STATE_CHANGE_SUCCESS;
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
ret = GST_STATE_CHANGE_FAILURE;
}
}
/* if nothing is pending anymore we can return SUCCESS */
if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
ret = GST_STATE_CHANGE_SUCCESS;
}
}
done:
if (state)
*state = GST_STATE (element);
if (pending)
*pending = GST_STATE_PENDING (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"state current: %s, pending: %s, result: %s",
gst_element_state_get_name (GST_STATE (element)),
gst_element_state_get_name (GST_STATE_PENDING (element)),
gst_element_state_change_return_get_name (ret));
GST_OBJECT_UNLOCK (element);
return ret;
interrupted:
{
if (state)
*state = GST_STATE_VOID_PENDING;
if (pending)
*pending = GST_STATE_VOID_PENDING;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
GST_OBJECT_UNLOCK (element);
return GST_STATE_CHANGE_FAILURE;
}
}
/**
* gst_element_get_state:
* @element: a #GstElement to get the state of.
* @state: (out) (allow-none): a pointer to #GstState to hold the state.
* Can be %NULL.
* @pending: (out) (allow-none): a pointer to #GstState to hold the pending
* state. Can be %NULL.
* @timeout: a #GstClockTime to specify the timeout for an async
* state change or %GST_CLOCK_TIME_NONE for infinite timeout.
*
* Gets the state of the element.
*
* For elements that performed an ASYNC state change, as reported by
* gst_element_set_state(), this function will block up to the
* specified timeout value for the state change to complete.
* If the element completes the state change or goes into
* an error, this function returns immediately with a return value of
* %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
*
* For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
* returns the current and pending state immediately.
*
* This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
* successfully changed its state but is not able to provide data yet.
* This mostly happens for live sources that only produce data in
* %GST_STATE_PLAYING. While the state change return is equivalent to
* %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
* some sink elements might not be able to complete their state change because
* an element is not producing data to complete the preroll. When setting the
* element to playing, the preroll will complete and playback will start.
*
* Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
* and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
* element is still performing a state change or
* %GST_STATE_CHANGE_FAILURE if the last state change failed.
*
* MT safe.
*/
GstStateChangeReturn
gst_element_get_state (GstElement * element,
GstState * state, GstState * pending, GstClockTime timeout)
{
GstElementClass *oclass;
GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->get_state)
result = (oclass->get_state) (element, state, pending, timeout);
return result;
}
/**
* gst_element_abort_state:
* @element: a #GstElement to abort the state of.
*
* Abort the state change of the element. This function is used
* by elements that do asynchronous state changes and find out
* something is wrong.
*
* This function should be called with the STATE_LOCK held.
*
* MT safe.
*/
void
gst_element_abort_state (GstElement * element)
{
GstState pending;
#ifndef GST_DISABLE_GST_DEBUG
GstState old_state;
#endif
g_return_if_fail (GST_IS_ELEMENT (element));
GST_OBJECT_LOCK (element);
pending = GST_STATE_PENDING (element);
if (pending == GST_STATE_VOID_PENDING ||
GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
goto nothing_aborted;
#ifndef GST_DISABLE_GST_DEBUG
old_state = GST_STATE (element);
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"aborting state from %s to %s", gst_element_state_get_name (old_state),
gst_element_state_get_name (pending));
#endif
/* flag error */
GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
GST_STATE_BROADCAST (element);
GST_OBJECT_UNLOCK (element);
return;
nothing_aborted:
{
GST_OBJECT_UNLOCK (element);
return;
}
}
/**
* gst_element_continue_state:
* @element: a #GstElement to continue the state change of.
* @ret: The previous state return value
*
* Commit the state change of the element and proceed to the next
* pending state if any. This function is used
* by elements that do asynchronous state changes.
* The core will normally call this method automatically when an
* element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
*
* If after calling this method the element still has not reached
* the pending state, the next state change is performed.
*
* This method is used internally and should normally not be called by plugins
* or applications.
*
* Returns: The result of the commit state change.
*
* MT safe.
*/
GstStateChangeReturn
gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
{
GstStateChangeReturn old_ret;
GstState old_state, old_next;
GstState current, next, pending;
GstMessage *message;
GstStateChange transition;
GST_OBJECT_LOCK (element);
old_ret = GST_STATE_RETURN (element);
GST_STATE_RETURN (element) = ret;
pending = GST_STATE_PENDING (element);
/* check if there is something to commit */
if (pending == GST_STATE_VOID_PENDING)
goto nothing_pending;
old_state = GST_STATE (element);
/* this is the state we should go to next */
old_next = GST_STATE_NEXT (element);
/* update current state */
current = GST_STATE (element) = old_next;
/* see if we reached the final state */
if (pending == current)
goto complete;
next = GST_STATE_GET_NEXT (current, pending);
transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
GST_STATE_NEXT (element) = next;
/* mark busy */
GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
GST_OBJECT_UNLOCK (element);
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"committing state from %s to %s, pending %s, next %s",
gst_element_state_get_name (old_state),
gst_element_state_get_name (old_next),
gst_element_state_get_name (pending), gst_element_state_get_name (next));
message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
old_state, old_next, pending);
gst_element_post_message (element, message);
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"continue state change %s to %s, final %s",
gst_element_state_get_name (current),
gst_element_state_get_name (next), gst_element_state_get_name (pending));
ret = gst_element_change_state (element, transition);
return ret;
nothing_pending:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
GST_OBJECT_UNLOCK (element);
return ret;
}
complete:
{
GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"completed state change to %s", gst_element_state_get_name (pending));
GST_OBJECT_UNLOCK (element);
/* don't post silly messages with the same state. This can happen
* when an element state is changed to what it already was. For bins
* this can be the result of a lost state, which we check with the
* previous return value.
* We do signal the cond though as a _get_state() might be blocking
* on it. */
if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"posting state-changed %s to %s",
gst_element_state_get_name (old_state),
gst_element_state_get_name (old_next));
message =
gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
old_next, GST_STATE_VOID_PENDING);
gst_element_post_message (element, message);
}
GST_STATE_BROADCAST (element);
return ret;
}
}
/**
* gst_element_lost_state_full:
* @element: a #GstElement the state is lost of
* @new_base_time: if a new base time should be distributed
*
* Brings the element to the lost state. The current state of the
* element is copied to the pending state so that any call to
* gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
*
* An ASYNC_START message is posted with indication to distribute a new
* base_time to the element when @new_base_time is %TRUE.
* If the element was PLAYING, it will go to PAUSED. The element
* will be restored to its PLAYING state by the parent pipeline when it
* prerolls again.
*
* This is mostly used for elements that lost their preroll buffer
* in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
* they will go to their pending state again when a new preroll buffer is
* queued. This function can only be called when the element is currently
* not in error or an async state change.
*
* This function is used internally and should normally not be called from
* plugins or applications.
*
* MT safe.
*
* Since: 0.10.24
*/
void
gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
{
GstState old_state, new_state;
GstMessage *message;
g_return_if_fail (GST_IS_ELEMENT (element));
GST_OBJECT_LOCK (element);
if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
goto nothing_lost;
if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
goto only_async_start;
old_state = GST_STATE (element);
/* when we were PLAYING, the new state is PAUSED. We will also not
* automatically go to PLAYING but let the parent bin(s) set us to PLAYING
* when we preroll. */
if (old_state > GST_STATE_PAUSED)
new_state = GST_STATE_PAUSED;
else
new_state = old_state;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"lost state of %s to %s", gst_element_state_get_name (old_state),
gst_element_state_get_name (new_state));
GST_STATE (element) = new_state;
GST_STATE_NEXT (element) = new_state;
GST_STATE_PENDING (element) = new_state;
GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
if (new_base_time)
GST_ELEMENT_START_TIME (element) = 0;
GST_OBJECT_UNLOCK (element);
message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
new_state, new_state, new_state);
gst_element_post_message (element, message);
message =
gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
gst_element_post_message (element, message);
return;
nothing_lost:
{
GST_OBJECT_UNLOCK (element);
return;
}
only_async_start:
{
GST_OBJECT_UNLOCK (element);
message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
gst_element_post_message (element, message);
return;
}
}
/**
* gst_element_lost_state:
* @element: a #GstElement the state is lost of
*
* Brings the element to the lost state. This function calls
* gst_element_lost_state_full() with the new_base_time set to %TRUE.
*
* This function is used internally and should normally not be called from
* plugins or applications.
*
* MT safe.
*/
void
gst_element_lost_state (GstElement * element)
{
gst_element_lost_state_full (element, TRUE);
}
/**
* gst_element_set_state:
* @element: a #GstElement to change state of.
* @state: the element's new #GstState.
*
* Sets the state of the element. This function will try to set the
* requested state by going through all the intermediary states and calling
* the class's state change function for each.
*
* This function can return #GST_STATE_CHANGE_ASYNC, in which case the
* element will perform the remainder of the state change asynchronously in
* another thread.
* An application can use gst_element_get_state() to wait for the completion
* of the state change or it can wait for a state change message on the bus.
*
* State changes to %GST_STATE_READY or %GST_STATE_NULL never return
* #GST_STATE_CHANGE_ASYNC.
*
* Returns: Result of the state change using #GstStateChangeReturn.
*
* MT safe.
*/
GstStateChangeReturn
gst_element_set_state (GstElement * element, GstState state)
{
GstElementClass *oclass;
GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->set_state)
result = (oclass->set_state) (element, state);
return result;
}
/*
* default set state function, calculates the next state based
* on current state and calls the change_state function
*/
static GstStateChangeReturn
gst_element_set_state_func (GstElement * element, GstState state)
{
GstState current, next, old_pending;
GstStateChangeReturn ret;
GstStateChange transition;
GstStateChangeReturn old_ret;
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
gst_element_state_get_name (state));
/* state lock is taken to protect the set_state() and get_state()
* procedures, it does not lock any variables. */
GST_STATE_LOCK (element);
/* now calculate how to get to the new state */
GST_OBJECT_LOCK (element);
old_ret = GST_STATE_RETURN (element);
/* previous state change returned an error, remove all pending
* and next states */
if (old_ret == GST_STATE_CHANGE_FAILURE) {
GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
}
current = GST_STATE (element);
next = GST_STATE_NEXT (element);
old_pending = GST_STATE_PENDING (element);
/* this is the (new) state we should go to. TARGET is the last state we set on
* the element. */
if (state != GST_STATE_TARGET (element)) {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"setting target state to %s", gst_element_state_get_name (state));
GST_STATE_TARGET (element) = state;
/* increment state cookie so that we can track each state change. We only do
* this if this is actually a new state change. */
element->state_cookie++;
}
GST_STATE_PENDING (element) = state;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"current %s, old_pending %s, next %s, old return %s",
gst_element_state_get_name (current),
gst_element_state_get_name (old_pending),
gst_element_state_get_name (next),
gst_element_state_change_return_get_name (old_ret));
/* if the element was busy doing a state change, we just update the
* target state, it'll get to it async then. */
if (old_pending != GST_STATE_VOID_PENDING) {
/* upwards state change will happen ASYNC */
if (old_pending <= state)
goto was_busy;
/* element is going to this state already */
else if (next == state)
goto was_busy;
/* element was performing an ASYNC upward state change and
* we request to go downward again. Start from the next pending
* state then. */
else if (next > state
&& GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
current = next;
}
}
next = GST_STATE_GET_NEXT (current, state);
/* now we store the next state */
GST_STATE_NEXT (element) = next;
/* mark busy, we need to check that there is actually a state change
* to be done else we could accidentally override SUCCESS/NO_PREROLL and
* the default element change_state function has no way to know what the
* old value was... could consider this a FIXME...*/
if (current != next)
GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"%s: setting state from %s to %s",
(next != state ? "intermediate" : "final"),
gst_element_state_get_name (current), gst_element_state_get_name (next));
/* now signal any waiters, they will error since the cookie was incremented */
GST_STATE_BROADCAST (element);
GST_OBJECT_UNLOCK (element);
ret = gst_element_change_state (element, transition);
GST_STATE_UNLOCK (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
gst_element_state_change_return_get_name (ret));
return ret;
was_busy:
{
GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"element was busy with async state change");
GST_OBJECT_UNLOCK (element);
GST_STATE_UNLOCK (element);
return GST_STATE_CHANGE_ASYNC;
}
}
/**
* gst_element_change_state:
* @element: a #GstElement
* @transition: the requested transition
*
* Perform @transition on @element.
*
* This function must be called with STATE_LOCK held and is mainly used
* internally.
*
* Returns: the #GstStateChangeReturn of the state transition.
*/
GstStateChangeReturn
gst_element_change_state (GstElement * element, GstStateChange transition)
{
GstElementClass *oclass;
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
oclass = GST_ELEMENT_GET_CLASS (element);
/* call the state change function so it can set the state */
if (oclass->change_state)
ret = (oclass->change_state) (element, transition);
else
ret = GST_STATE_CHANGE_FAILURE;
switch (ret) {
case GST_STATE_CHANGE_FAILURE:
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"have FAILURE change_state return");
/* state change failure */
gst_element_abort_state (element);
break;
case GST_STATE_CHANGE_ASYNC:
{
GstState target;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"element will change state ASYNC");
target = GST_STATE_TARGET (element);
if (target > GST_STATE_READY)
goto async;
/* else we just continue the state change downwards */
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"forcing commit state %s <= %s",
gst_element_state_get_name (target),
gst_element_state_get_name (GST_STATE_READY));
ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
break;
}
case GST_STATE_CHANGE_SUCCESS:
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"element changed state SUCCESS");
/* we can commit the state now which will proceeed to
* the next state */
ret = gst_element_continue_state (element, ret);
break;
case GST_STATE_CHANGE_NO_PREROLL:
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"element changed state NO_PREROLL");
/* we can commit the state now which will proceeed to
* the next state */
ret = gst_element_continue_state (element, ret);
break;
default:
goto invalid_return;
}
GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
return ret;
async:
GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
ret);
return ret;
/* ERROR */
invalid_return:
{
GST_OBJECT_LOCK (element);
/* somebody added a GST_STATE_ and forgot to do stuff here ! */
g_critical ("%s: unknown return value %d from a state change function",
GST_ELEMENT_NAME (element), ret);
/* we are in error now */
ret = GST_STATE_CHANGE_FAILURE;
GST_STATE_RETURN (element) = ret;
GST_OBJECT_UNLOCK (element);
return ret;
}
}
/* gst_iterator_fold functions for pads_activate
* Note how we don't stop the iterator when we fail an activation. This is
* probably a FIXME since when one pad activation fails, we don't want to
* continue our state change. */
static gboolean
activate_pads (GstPad * pad, GValue * ret, gboolean * active)
{
if (!gst_pad_set_active (pad, *active))
g_value_set_boolean (ret, FALSE);
/* unref the object that was reffed for us by _fold */
gst_object_unref (pad);
return TRUE;
}
/* set the caps on the pad to NULL */
static gboolean
clear_caps (GstPad * pad, GValue * ret, gboolean * active)
{
gst_pad_set_caps (pad, NULL);
gst_object_unref (pad);
return TRUE;
}
/* returns false on error or early cutout (will never happen because the fold
* function always returns TRUE, see FIXME above) of the fold, true if all
* pads in @iter were (de)activated successfully. */
static gboolean
iterator_activate_fold_with_resync (GstIterator * iter,
GstIteratorFoldFunction func, gpointer user_data)
{
GstIteratorResult ires;
GValue ret = { 0 };
/* no need to unset this later, it's just a boolean */
g_value_init (&ret, G_TYPE_BOOLEAN);
g_value_set_boolean (&ret, TRUE);
while (1) {
ires = gst_iterator_fold (iter, func, &ret, user_data);
switch (ires) {
case GST_ITERATOR_RESYNC:
/* need to reset the result again */
g_value_set_boolean (&ret, TRUE);
gst_iterator_resync (iter);
break;
case GST_ITERATOR_DONE:
/* all pads iterated, return collected value */
goto done;
default:
/* iterator returned _ERROR or premature end with _OK,
* mark an error and exit */
g_value_set_boolean (&ret, FALSE);
goto done;
}
}
done:
/* return collected value */
return g_value_get_boolean (&ret);
}
/* is called with STATE_LOCK
*
* Pads are activated from source pads to sinkpads.
*/
static gboolean
gst_element_pads_activate (GstElement * element, gboolean active)
{
GstIterator *iter;
gboolean res;
GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
"pads_activate with active %d", active);
iter = gst_element_iterate_src_pads (element);
res =
iterator_activate_fold_with_resync (iter,
(GstIteratorFoldFunction) activate_pads, &active);
gst_iterator_free (iter);
if (G_UNLIKELY (!res))
goto src_failed;
iter = gst_element_iterate_sink_pads (element);
res =
iterator_activate_fold_with_resync (iter,
(GstIteratorFoldFunction) activate_pads, &active);
gst_iterator_free (iter);
if (G_UNLIKELY (!res))
goto sink_failed;
if (!active) {
/* clear the caps on all pads, this should never fail */
iter = gst_element_iterate_pads (element);
res =
iterator_activate_fold_with_resync (iter,
(GstIteratorFoldFunction) clear_caps, &active);
gst_iterator_free (iter);
if (G_UNLIKELY (!res))
goto caps_failed;
}
GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
"pads_activate successful");
return TRUE;
/* ERRORS */
src_failed:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
"source pads_activate failed");
return FALSE;
}
sink_failed:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
"sink pads_activate failed");
return FALSE;
}
caps_failed:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
"failed to clear caps on pads");
return FALSE;
}
}
/* is called with STATE_LOCK */
static GstStateChangeReturn
gst_element_change_state_func (GstElement * element, GstStateChange transition)
{
GstState state, next;
GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
GstClock **clock_p;
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
next = GST_STATE_TRANSITION_NEXT (transition);
/* if the element already is in the given state, we just return success */
if (next == GST_STATE_VOID_PENDING || state == next)
goto was_ok;
GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
"default handler tries setting state from %s to %s (%04x)",
gst_element_state_get_name (state),
gst_element_state_get_name (next), transition);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
if (!gst_element_pads_activate (element, TRUE)) {
result = GST_STATE_CHANGE_FAILURE;
}
break;
case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
break;
case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
case GST_STATE_CHANGE_READY_TO_NULL:
/* deactivate pads in both cases, since they are activated on
ready->paused but the element might not have made it to paused */
if (!gst_element_pads_activate (element, FALSE)) {
result = GST_STATE_CHANGE_FAILURE;
} else {
gst_element_set_base_time (element, 0);
}
/* In null state release the reference to the clock */
GST_OBJECT_LOCK (element);
clock_p = &element->clock;
gst_object_replace ((GstObject **) clock_p, NULL);
GST_OBJECT_UNLOCK (element);
break;
default:
/* this will catch real but unhandled state changes;
* can only be caused by:
* - a new state was added
* - somehow the element was asked to jump across an intermediate state
*/
g_warning ("Unhandled state change from %s to %s",
gst_element_state_get_name (state),
gst_element_state_get_name (next));
break;
}
return result;
was_ok:
{
GST_OBJECT_LOCK (element);
result = GST_STATE_RETURN (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"element is already in the %s state",
gst_element_state_get_name (state));
GST_OBJECT_UNLOCK (element);
return result;
}
}
/**
* gst_element_get_factory:
* @element: a #GstElement to request the element factory of.
*
* Retrieves the factory that was used to create this element.
*
* Returns: (transfer none): the #GstElementFactory used for creating this
* element. no refcounting is needed.
*/
GstElementFactory *
gst_element_get_factory (GstElement * element)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return GST_ELEMENT_GET_CLASS (element)->elementfactory;
}
static void
gst_element_dispose (GObject * object)
{
GstElement *element = GST_ELEMENT_CAST (object);
GstClock **clock_p;
GstBus **bus_p;
GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
if (GST_STATE (element) != GST_STATE_NULL)
goto not_null;
GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
"removing %d pads", g_list_length (element->pads));
/* first we break all our links with the outside */
while (element->pads && element->pads->data) {
/* don't call _remove_pad with NULL */
gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
}
if (G_UNLIKELY (element->pads != NULL)) {
g_critical ("could not remove pads from element %s",
GST_STR_NULL (GST_OBJECT_NAME (object)));
}
GST_OBJECT_LOCK (element);
clock_p = &element->clock;
bus_p = &element->bus;
gst_object_replace ((GstObject **) clock_p, NULL);
gst_object_replace ((GstObject **) bus_p, NULL);
GST_OBJECT_UNLOCK (element);
GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
G_OBJECT_CLASS (parent_class)->dispose (object);
return;
/* ERRORS */
not_null:
{
gboolean is_locked;
is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
g_critical
("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
" state.\n"
"You need to explicitly set elements to the NULL state before\n"
"dropping the final reference, to allow them to clean up.\n"
"This problem may also be caused by a refcounting bug in the\n"
"application or some element.\n",
GST_OBJECT_NAME (element),
gst_element_state_get_name (GST_STATE (element)),
is_locked ? " (locked)" : "");
return;
}
}
static void
gst_element_finalize (GObject * object)
{
GstElement *element = GST_ELEMENT_CAST (object);
GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
GST_STATE_LOCK (element);
if (element->state_cond)
g_cond_free (element->state_cond);
element->state_cond = NULL;
GST_STATE_UNLOCK (element);
g_static_rec_mutex_free (element->state_lock);
g_slice_free (GStaticRecMutex, element->state_lock);
element->state_lock = NULL;
GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
G_OBJECT_CLASS (parent_class)->finalize (object);
}
#if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
/**
* gst_element_save_thyself:
* @element: a #GstElement to save.
* @parent: the xml parent node.
*
* Saves the element as part of the given XML structure.
*
* Returns: the new #xmlNodePtr.
*/
static xmlNodePtr
gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
{
GList *pads;
GstElementClass *oclass;
GParamSpec **specs, *spec;
guint nspecs;
guint i;
GValue value = { 0, };
GstElement *element;
g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
element = GST_ELEMENT_CAST (object);
oclass = GST_ELEMENT_GET_CLASS (element);
xmlNewChild (parent, NULL, (xmlChar *) "name",
(xmlChar *) GST_ELEMENT_NAME (element));
if (oclass->elementfactory != NULL) {
GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
xmlNewChild (parent, NULL, (xmlChar *) "type",
(xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
}
/* params */
specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
for (i = 0; i < nspecs; i++) {
spec = specs[i];
if (spec->flags & G_PARAM_READABLE) {
xmlNodePtr param;
char *contents;
g_value_init (&value, spec->value_type);
g_object_get_property (G_OBJECT (element), spec->name, &value);
param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
if (G_IS_PARAM_SPEC_STRING (spec))
contents = g_value_dup_string (&value);
else if (G_IS_PARAM_SPEC_ENUM (spec))
contents = g_strdup_printf ("%d", g_value_get_enum (&value));
else if (G_IS_PARAM_SPEC_INT64 (spec))
contents = g_strdup_printf ("%" G_GINT64_FORMAT,
g_value_get_int64 (&value));
else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
if (g_value_get_boxed (&value) != NULL) {
contents = g_strdup_value_contents (&value);
} else {
contents = g_strdup ("NULL");
}
} else
contents = g_strdup_value_contents (&value);
xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
g_free (contents);
g_value_unset (&value);
}
}
g_free (specs);
pads = g_list_last (GST_ELEMENT_PADS (element));
while (pads) {
GstPad *pad = GST_PAD_CAST (pads->data);
/* figure out if it's a direct pad or a ghostpad */
if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
}
pads = g_list_previous (pads);
}
return parent;
}
static void
gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
{
xmlNodePtr children;
GstElement *element;
gchar *name = NULL;
gchar *value = NULL;
element = GST_ELEMENT_CAST (object);
g_return_if_fail (element != NULL);
/* parameters */
children = self->xmlChildrenNode;
while (children) {
if (!strcmp ((char *) children->name, "param")) {
xmlNodePtr child = children->xmlChildrenNode;
while (child) {
if (!strcmp ((char *) child->name, "name")) {
name = (gchar *) xmlNodeGetContent (child);
} else if (!strcmp ((char *) child->name, "value")) {
value = (gchar *) xmlNodeGetContent (child);
}
child = child->next;
}
/* FIXME: can this just be g_object_set ? */
gst_util_set_object_arg (G_OBJECT (element), name, value);
/* g_object_set (G_OBJECT (element), name, value, NULL); */
g_free (name);
g_free (value);
}
children = children->next;
}
/* pads */
children = self->xmlChildrenNode;
while (children) {
if (!strcmp ((char *) children->name, "pad")) {
gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
}
children = children->next;
}
if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
(GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
}
#endif /* GST_DISABLE_LOADSAVE */
static void
gst_element_set_bus_func (GstElement * element, GstBus * bus)
{
GstBus **bus_p;
g_return_if_fail (GST_IS_ELEMENT (element));
GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
GST_OBJECT_LOCK (element);
bus_p = &GST_ELEMENT_BUS (element);
gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
GST_OBJECT_UNLOCK (element);
}
/**
* gst_element_set_bus:
* @element: a #GstElement to set the bus of.
* @bus: (transfer none): the #GstBus to set.
*
* Sets the bus of the element. Increases the refcount on the bus.
* For internal use only, unless you're testing elements.
*
* MT safe.
*/
void
gst_element_set_bus (GstElement * element, GstBus * bus)
{
GstElementClass *oclass;
g_return_if_fail (GST_IS_ELEMENT (element));
oclass = GST_ELEMENT_GET_CLASS (element);
if (oclass->set_bus)
oclass->set_bus (element, bus);
}
/**
* gst_element_get_bus:
* @element: a #GstElement to get the bus of.
*
* Returns the bus of the element. Note that only a #GstPipeline will provide a
* bus for the application.
*
* Returns: (transfer full): the element's #GstBus. unref after usage.
*
* MT safe.
*/
GstBus *
gst_element_get_bus (GstElement * element)
{
GstBus *result = NULL;
g_return_val_if_fail (GST_IS_ELEMENT (element), result);
GST_OBJECT_LOCK (element);
if ((result = GST_ELEMENT_BUS (element)))
gst_object_ref (result);
GST_OBJECT_UNLOCK (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
result);
return result;
}
Reference in a new issue View git blame Copy permalink