blob: 8a908a1a5ae0b700f758109a7b6461c2afd25480 [file] [log] [blame]
/* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstelement
* @title: 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.
*
* Elements can 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().
*
* An existing pad of an element can be retrieved by name with
* gst_element_get_static_pad(). A new dynamic pad can be created using
* gst_element_request_pad() with a #GstPadTemplate.
* 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
* the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. 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 the
* #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
* element with gst_element_set_clock().
*
* Note that clock selection and distribution is normally handled by the
* toplevel #GstPipeline so the clock functions are only to be used in very
* specific situations.
*/
#include "gst_private.h"
#include <glib.h>
#include <stdarg.h>
#include <gobject/gvaluecollector.h>
#include "gstelement.h"
#include "gstelementmetadata.h"
#include "gstenumtypes.h"
#include "gstbus.h"
#include "gsterror.h"
#include "gstevent.h"
#include "gstutils.h"
#include "gstinfo.h"
#include "gstquark.h"
#include "gsttracerutils.h"
#include "gstvalue.h"
#include "gst-i18n-lib.h"
#include "glib-compat-private.h"
#ifndef GST_DISABLE_GST_DEBUG
#include "printf/printf.h"
#endif
/* Element signals and args */
enum
{
PAD_ADDED,
PAD_REMOVED,
NO_MORE_PADS,
/* add more above */
LAST_SIGNAL
};
enum
{
ARG_0
/* FILL ME */
};
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_constructed (GObject * object);
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 gboolean gst_element_set_clock_func (GstElement * element,
GstClock * clock);
static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
static gboolean gst_element_post_message_default (GstElement * element,
GstMessage * message);
static void gst_element_set_context_default (GstElement * element,
GstContext * context);
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);
static void gst_element_call_async_func (gpointer data, gpointer user_data);
static GstObjectClass *parent_class = NULL;
static guint gst_element_signals[LAST_SIGNAL] = { 0 };
static GThreadPool *gst_element_pool = NULL;
/* 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,
NULL, /* 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_setup_thread_pool (void)
{
GError *err = NULL;
GST_DEBUG ("creating element thread pool");
gst_element_pool =
g_thread_pool_new ((GFunc) gst_element_call_async_func, NULL, -1, FALSE,
&err);
if (err != NULL) {
g_critical ("could not alloc threadpool %s", err->message);
g_clear_error (&err);
}
}
static void
gst_element_class_init (GstElementClass * klass)
{
GObjectClass *gobject_class;
gobject_class = (GObjectClass *) 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. Note that this signal will
* usually be emitted from the context of the streaming thread. Also keep in
* mind that if you add new elements to the pipeline in the signal handler
* you will need to set them to the desired target state with
* gst_element_set_state() or gst_element_sync_state_with_parent().
*/
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,
g_cclosure_marshal_generic, 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,
g_cclosure_marshal_generic, 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.
* Note that this signal will usually be emitted from the context of
* the streaming thread.
*/
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, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
gobject_class->dispose = gst_element_dispose;
gobject_class->finalize = gst_element_finalize;
gobject_class->constructed = gst_element_constructed;
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_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_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->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_default);
klass->elementfactory = NULL;
gst_element_setup_thread_pool ();
}
static void
gst_element_base_class_init (gpointer g_class)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
GList *node, *padtemplates;
/* Copy the element details here so elements can inherit the
* details from their base class and classes only need to set
* the details in class_init instead of base_init */
element_class->metadata =
element_class->metadata ? gst_structure_copy (element_class->metadata) :
gst_structure_new_empty ("metadata");
/* Copy the pad templates so elements inherit them
* from their base class but elements can add pad templates in class_init
* instead of base_init.
*/
padtemplates = g_list_copy (element_class->padtemplates);
for (node = padtemplates; node != NULL; node = node->next) {
GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
gst_object_ref (tmpl);
}
element_class->padtemplates = padtemplates;
/* set the factory, see gst_element_register() */
element_class->elementfactory =
g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
__gst_elementclass_factory);
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
}
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;
g_rec_mutex_init (&element->state_lock);
g_cond_init (&element->state_cond);
}
static void
gst_element_constructed (GObject * object)
{
GST_TRACER_ELEMENT_NEW (GST_ELEMENT_CAST (object));
G_OBJECT_CLASS (parent_class)->constructed (object);
}
/**
* 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_request_pad().
*
* This does not unref the pad. If the pad was created by using
* gst_element_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));
g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
GST_PAD_REQUEST);
g_return_if_fail (GST_PAD_PARENT (pad) == element);
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_provide_clock:
* @element: a #GstElement to query
*
* Get the clock provided by the given element.
* > An element is only required to provide a clock in the PAUSED
* > state. Some elements can provide a clock in other states.
*
* Returns: (transfer full) (nullable): 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;
}
static gboolean
gst_element_set_clock_func (GstElement * element, GstClock * clock)
{
GstClock **clock_p;
GST_OBJECT_LOCK (element);
clock_p = &element->clock;
gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
GST_OBJECT_UNLOCK (element);
return TRUE;
}
/**
* gst_element_set_clock:
* @element: a #GstElement to set the clock for.
* @clock: (transfer none) (allow-none): 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 = FALSE;
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);
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().
*
* Elements in a pipeline will only have their clock set when the
* pipeline is in the PLAYING state.
*
* Returns: (transfer full) (nullable): 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.
*/
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.
*/
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;
}
#if 0
/**
* 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) (nullable): 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;
}
#endif
/**
* gst_element_add_pad:
* @element: a #GstElement to add the pad to.
* @pad: (transfer floating): 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 active;
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));
active = GST_PAD_IS_ACTIVE (pad);
GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
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 active pads */
if (!active && (GST_STATE (element) > GST_STATE_READY ||
GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
g_warning ("adding inactive 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));
gst_pad_set_active (pad, TRUE);
}
g_free (pad_name);
/* add it to the list */
switch (gst_pad_get_direction (pad)) {
case GST_PAD_SRC:
element->srcpads = g_list_append (element->srcpads, pad);
element->numsrcpads++;
break;
case GST_PAD_SINK:
element->sinkpads = g_list_append (element->sinkpads, pad);
element->numsinkpads++;
break;
default:
goto no_direction;
}
element->pads = g_list_append (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);
GST_TRACER_ELEMENT_ADD_PAD (element, 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);
gst_object_ref_sink (pad);
gst_object_unref (pad);
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_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_TRACER_ELEMENT_REMOVE_PAD (element, pad);
gst_object_unparent (GST_OBJECT_CAST (pad));
return TRUE;
/* ERRORS */
not_our_pad:
{
/* locking order is element > pad */
GST_OBJECT_UNLOCK (pad);
GST_OBJECT_LOCK (element);
GST_OBJECT_LOCK (pad);
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 (pad);
GST_OBJECT_UNLOCK (element);
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) (nullable): 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 gboolean
gst_element_is_valid_request_template_name (const gchar * templ_name,
const gchar * name)
{
gchar *endptr;
const gchar *templ_name_ptr, *name_ptr;
gboolean next_specifier;
guint templ_postfix_len = 0, name_postfix_len = 0;
g_return_val_if_fail (templ_name != NULL, FALSE);
g_return_val_if_fail (name != NULL, FALSE);
/* Is this the template name? */
if (strcmp (templ_name, name) == 0)
return TRUE;
/* otherwise check all the specifiers */
do {
/* Because of sanity checks in gst_pad_template_new(), we know that %s
* and %d and %u, occurring at the template_name */
templ_name_ptr = strchr (templ_name, '%');
/* check characters ahead of the specifier */
if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
|| strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
return FALSE;
}
/* %s is not allowed for multiple specifiers, just a single specifier can be
* accepted in gst_pad_template_new() and can not be mixed with other
* specifier '%u' and '%d' */
if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
return TRUE;
}
name_ptr = name + (templ_name_ptr - templ_name);
/* search next specifier, each of specifier should be separated by '_' */
templ_name = strchr (templ_name_ptr, '_');
name = strchr (name_ptr, '_');
/* don't match the number of specifiers */
if ((templ_name && !name) || (!templ_name && name))
return FALSE;
if (templ_name && name)
next_specifier = TRUE;
else
next_specifier = FALSE;
/* check characters followed by the specifier */
if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
if (next_specifier) {
templ_postfix_len = templ_name - (templ_name_ptr + 2);
name_postfix_len = name - name_ptr;
} else {
templ_postfix_len = strlen (templ_name_ptr + 2);
name_postfix_len = strlen (name_ptr);
}
if (strncmp (templ_name_ptr + 2,
name_ptr + name_postfix_len - templ_postfix_len,
templ_postfix_len) != 0) {
return FALSE;
}
}
/* verify the specifier */
if (*(name_ptr) == '%') {
guint len;
len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
if (strncmp (name_ptr, templ_name_ptr, len) != 0)
return FALSE;
} else {
const gchar *specifier;
gchar *target = NULL;
/* extract specifier when it has postfix characters */
if (name_postfix_len > templ_postfix_len) {
target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
}
specifier = target ? target : name_ptr;
if (*(templ_name_ptr + 1) == 'd') {
gint64 tmp;
/* it's an int */
tmp = g_ascii_strtoll (specifier, &endptr, 10);
if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
&& *endptr != '_'))
return FALSE;
} else if (*(templ_name_ptr + 1) == 'u') {
guint64 tmp;
/* it's an int */
tmp = g_ascii_strtoull (specifier, &endptr, 10);
if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
return FALSE;
}
g_free (target);
}
/* otherwise we increment these from NULL to 1 */
if (next_specifier) {
templ_name++;
name++;
}
} while (next_specifier);
return TRUE;
}
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);
#ifndef G_DISABLE_CHECKS
/* Some sanity checking here */
if (name) {
GstPad *pad;
g_return_val_if_fail (gst_element_is_valid_request_template_name
(templ->name_template, name), NULL);
pad = gst_element_get_static_pad (element, name);
if (pad) {
gst_object_unref (pad);
/* FIXME 2.0: Change this to g_return_val_if_fail() */
g_critical ("Element %s already has a pad named %s, the behaviour of "
" gst_element_get_request_pad() for existing pads is undefined!",
GST_ELEMENT_NAME (element), name);
}
}
#endif
if (oclass->request_new_pad)
newpad = (oclass->request_new_pad) (element, templ, name, caps);
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 (e.g. "src_\%d"). This version only
* retrieves request pads. The pad should be released with
* gst_element_release_request_pad().
*
* This method is slower than manually getting the pad template and calling
* gst_element_request_pad() if the pads should have a specific name (e.g.
* @name is "src_1" instead of "src_\%u").
*
* Returns: (transfer full) (nullable): 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;
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);
templ = gst_element_class_get_request_pad_template (class, name);
if (templ) {
req_name = strstr (name, "%") ? NULL : name;
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);
if (gst_element_is_valid_request_template_name (templ->name_template,
name)) {
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: (virtual request_new_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.
* Pad templates can be looked up using
* gst_element_factory_get_static_pad_templates().
*
* The pad should be released with gst_element_release_request_pad().
*
* Returns: (transfer full) (nullable): requested #GstPad if found,
* otherwise %NULL. Release after usage.
*/
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);
g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
return _gst_element_request_pad (element, templ, name, caps);
}
static GstIterator *
gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
{
GstIterator *result;
GST_OBJECT_LOCK (element);
result = gst_iterator_new_list (GST_TYPE_PAD,
GST_OBJECT_GET_LOCK (element),
&element->pads_cookie, padlist, (GObject *) element, NULL);
GST_OBJECT_UNLOCK (element);
return result;
}
/**
* gst_element_iterate_pads:
* @element: a #GstElement to iterate pads of.
*
* Retrieves an iterator of @element's pads. The iterator should
* be freed after usage. Also more specialized iterators exists such as
* gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
*
* The order of pads returned by the iterator will be the order in which
* the pads were added to the element.
*
* Returns: (transfer full): the #GstIterator of #GstPad.
*
* 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.
*
* The order of pads returned by the iterator will be the order in which
* the pads were added to the element.
*
* Returns: (transfer full): the #GstIterator of #GstPad.
*
* 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.
*
* The order of pads returned by the iterator will be the order in which
* the pads were added to the element.
*
* Returns: (transfer full): the #GstIterator of #GstPad.
*
* 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);
}
static gboolean
gst_element_do_foreach_pad (GstElement * element,
GstElementForeachPadFunc func, gpointer user_data,
GList ** p_pads, guint16 * p_npads)
{
gboolean ret = TRUE;
GstPad **pads;
guint n_pads, i;
GList *l;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (func != NULL, FALSE);
GST_OBJECT_LOCK (element);
n_pads = *p_npads;
pads = g_newa (GstPad *, n_pads + 1);
for (l = *p_pads, i = 0; l != NULL; l = l->next) {
g_assert (i < n_pads);
pads[i++] = gst_object_ref (l->data);
}
GST_OBJECT_UNLOCK (element);
if (n_pads == 0)
return FALSE;
for (i = 0; i < n_pads; ++i) {
ret = func (element, pads[i], user_data);
if (!ret)
break;
}
for (i = 0; i < n_pads; ++i)
gst_object_unref (pads[i]);
return ret;
}
/**
* gst_element_foreach_sink_pad:
* @element: a #GstElement to iterate sink pads of
* @func: (scope call): function to call for each sink pad
* @user_data: (closure): user data passed to @func
*
* Call @func with @user_data for each of @element's sink pads. @func will be
* called exactly once for each sink pad that exists at the time of this call,
* unless one of the calls to @func returns %FALSE in which case we will stop
* iterating pads and return early. If new sink pads are added or sink pads
* are removed while the sink pads are being iterated, this will not be taken
* into account until next time this function is used.
*
* Returns: %FALSE if @element had no sink pads or if one of the calls to @func
* returned %FALSE.
*
* Since: 1.14
*/
gboolean
gst_element_foreach_sink_pad (GstElement * element,
GstElementForeachPadFunc func, gpointer user_data)
{
return gst_element_do_foreach_pad (element, func, user_data,
&element->sinkpads, &element->numsinkpads);
}
/**
* gst_element_foreach_src_pad:
* @element: a #GstElement to iterate source pads of
* @func: (scope call): function to call for each source pad
* @user_data: (closure): user data passed to @func
*
* Call @func with @user_data for each of @element's source pads. @func will be
* called exactly once for each source pad that exists at the time of this call,
* unless one of the calls to @func returns %FALSE in which case we will stop
* iterating pads and return early. If new source pads are added or source pads
* are removed while the source pads are being iterated, this will not be taken
* into account until next time this function is used.
*
* Returns: %FALSE if @element had no source pads or if one of the calls
* to @func returned %FALSE.
*
* Since: 1.14
*/
gboolean
gst_element_foreach_src_pad (GstElement * element,
GstElementForeachPadFunc func, gpointer user_data)
{
return gst_element_do_foreach_pad (element, func, user_data,
&element->srcpads, &element->numsrcpads);
}
/**
* gst_element_foreach_pad:
* @element: a #GstElement to iterate pads of
* @func: (scope call): function to call for each pad
* @user_data: (closure): user data passed to @func
*
* Call @func with @user_data for each of @element's pads. @func will be called
* exactly once for each pad that exists at the time of this call, unless
* one of the calls to @func returns %FALSE in which case we will stop
* iterating pads and return early. If new pads are added or pads are removed
* while pads are being iterated, this will not be taken into account until
* next time this function is used.
*
* Returns: %FALSE if @element had no pads or if one of the calls to @func
* returned %FALSE.
*
* Since: 1.14
*/
gboolean
gst_element_foreach_pad (GstElement * element, GstElementForeachPadFunc func,
gpointer user_data)
{
return gst_element_do_foreach_pad (element, func, user_data,
&element->pads, &element->numpads);
}
/**
* gst_element_class_add_pad_template:
* @klass: the #GstElementClass to add the pad template to.
* @templ: (transfer floating): a #GstPadTemplate to add to the element class.
*
* Adds a padtemplate to an element class. This is mainly used in the _class_init
* functions of classes. If a pad template with the same name as an already
* existing one is added the old one is replaced by the new one.
*
* @templ's reference count will be incremented, and any floating
* reference will be removed (see gst_object_ref_sink())
*
*/
void
gst_element_class_add_pad_template (GstElementClass * klass,
GstPadTemplate * templ)
{
GList *template_list = klass->padtemplates;
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
/* If we already have a pad template with the same name replace the
* old one. */
while (template_list) {
GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
/* Found pad with the same name, replace and return */
if (strcmp (templ->name_template, padtempl->name_template) == 0) {
gst_object_ref_sink (padtempl);
gst_object_unref (padtempl);
template_list->data = templ;
return;
}
template_list = g_list_next (template_list);
}
/* Take ownership of the floating ref */
gst_object_ref_sink (templ);
klass->padtemplates = g_list_append (klass->padtemplates, templ);
klass->numpadtemplates++;
}
/**
* gst_element_class_add_static_pad_template:
* @klass: the #GstElementClass to add the pad template to.
* @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
*
* Adds a pad template to an element class based on the static pad template
* @templ. This is mainly used in the _class_init functions of element
* implementations. If a pad template with the same name already exists,
* the old one is replaced by the new one.
*
* Since: 1.8
*/
void
gst_element_class_add_static_pad_template (GstElementClass * klass,
GstStaticPadTemplate * static_templ)
{
gst_element_class_add_pad_template (klass,
gst_static_pad_template_get (static_templ));
}
/**
* gst_element_class_add_static_pad_template_with_gtype:
* @klass: the #GstElementClass to add the pad template to.
* @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
* @pad_type: The #GType of the pad to create
*
* Adds a pad template to an element class based on the static pad template
* @templ. This is mainly used in the _class_init functions of element
* implementations. If a pad template with the same name already exists,
* the old one is replaced by the new one.
*
* Since: 1.14
*/
void
gst_element_class_add_static_pad_template_with_gtype (GstElementClass * klass,
GstStaticPadTemplate * static_templ, GType pad_type)
{
gst_element_class_add_pad_template (klass,
gst_pad_template_new_from_static_pad_template_with_gtype (static_templ,
pad_type));
}
/**
* gst_element_class_add_metadata:
* @klass: class to set metadata for
* @key: the key to set
* @value: the value to set
*
* Set @key with @value as metadata in @klass.
*/
void
gst_element_class_add_metadata (GstElementClass * klass,
const gchar * key, const gchar * value)
{
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (key != NULL);
g_return_if_fail (value != NULL);
gst_structure_set ((GstStructure *) klass->metadata,
key, G_TYPE_STRING, value, NULL);
}
/**
* gst_element_class_add_static_metadata:
* @klass: class to set metadata for
* @key: the key to set
* @value: the value to set
*
* Set @key with @value as metadata in @klass.
*
* Same as gst_element_class_add_metadata(), but @value must be a static string
* or an inlined string, as it will not be copied. (GStreamer plugins will
* be made resident once loaded, so this function can be used even from
* dynamically loaded plugins.)
*/
void
gst_element_class_add_static_metadata (GstElementClass * klass,
const gchar * key, const gchar * value)
{
GValue val = G_VALUE_INIT;
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (key != NULL);
g_return_if_fail (value != NULL);
g_value_init (&val, G_TYPE_STRING);
g_value_set_static_string (&val, value);
gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
}
/**
* gst_element_class_set_metadata:
* @klass: class to set metadata 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 metadata. E.g: "Joe Bloggs &lt;joe.blogs at foo.com&gt;"
*
* Sets the detailed information for a #GstElementClass.
* > This function is for use in _class_init functions only.
*/
void
gst_element_class_set_metadata (GstElementClass * klass,
const gchar * longname, const gchar * classification,
const gchar * description, const gchar * author)
{
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (longname != NULL && *longname != '\0');
g_return_if_fail (classification != NULL && *classification != '\0');
g_return_if_fail (description != NULL && *description != '\0');
g_return_if_fail (author != NULL && *author != '\0');
gst_structure_id_set ((GstStructure *) klass->metadata,
GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
}
/**
* gst_element_class_set_static_metadata:
* @klass: class to set metadata 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 metadata. E.g: "Joe Bloggs &lt;joe.blogs at foo.com&gt;"
*
* Sets the detailed information for a #GstElementClass.
*
* > This function is for use in _class_init functions only.
*
* Same as gst_element_class_set_metadata(), but @longname, @classification,
* @description, and @author must be static strings or inlined strings, as
* they will not be copied. (GStreamer plugins will be made resident once
* loaded, so this function can be used even from dynamically loaded plugins.)
*/
void
gst_element_class_set_static_metadata (GstElementClass * klass,
const gchar * longname, const gchar * classification,
const gchar * description, const gchar * author)
{
GstStructure *s = (GstStructure *) klass->metadata;
GValue val = G_VALUE_INIT;
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (longname != NULL && *longname != '\0');
g_return_if_fail (classification != NULL && *classification != '\0');
g_return_if_fail (description != NULL && *description != '\0');
g_return_if_fail (author != NULL && *author != '\0');
g_value_init (&val, G_TYPE_STRING);
g_value_set_static_string (&val, longname);
gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
g_value_set_static_string (&val, classification);
gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
g_value_set_static_string (&val, description);
gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
&val);
g_value_set_static_string (&val, author);
gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
}
/**
* gst_element_class_get_metadata:
* @klass: class to get metadata for
* @key: the key to get
*
* Get metadata with @key in @klass.
*
* Returns: the metadata for @key.
*/
const gchar *
gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
{
g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
g_return_val_if_fail (key != NULL, NULL);
return gst_structure_get_string ((GstStructure *) klass->metadata, key);
}
/**
* gst_element_get_metadata:
* @element: class to get metadata for
* @key: the key to get
*
* Get metadata with @key in @klass.
*
* Returns: the metadata for @key.
*
* Since: 1.14
*/
const gchar *
gst_element_get_metadata (GstElement * element, const gchar * key)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (key != NULL, NULL);
return gst_element_class_get_metadata (GST_ELEMENT_GET_CLASS (element), key);
}
/**
* 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.
* > 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.
*
* 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_get_pad_template_list:
* @element: a #GstElement to get pad templates of.
*
* Retrieves a list of the pad templates associated with @element. The
* list must not be modified by the calling code.
*
* Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
* pad templates.
*
* Since: 1.14
*/
GList *
gst_element_get_pad_template_list (GstElement * element)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return
gst_element_class_get_pad_template_list (GST_ELEMENT_GET_CLASS (element));
}
/**
* 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.
* > 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.
*
* Returns: (transfer none) (nullable): 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;
}
/**
* gst_element_get_pad_template:
* @element: a #GstElement to get the pad template of.
* @name: the name of the #GstPadTemplate to get.
*
* Retrieves a padtemplate from @element with the given name.
*
* Returns: (transfer none) (nullable): the #GstPadTemplate with the
* given name, or %NULL if none was found. No unreferencing is
* necessary.
*
* Since: 1.14
*/
GstPadTemplate *
gst_element_get_pad_template (GstElement * element, const gchar * name)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
return gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (element),
name);
}
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_SINK) :
gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
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_send_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));
gst_event_unref (event);
}
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
* downstream events or a random linked source pad for upstream events.
*
* This function takes ownership of the provided event so you should
* gst_event_ref() it if you want to reuse the event after this call.
*
* MT safe.
*
* Returns: %TRUE if the event was handled. Events that trigger a preroll (such
* as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
*/
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 {
gst_event_unref (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.
* @start_type: The type and flags for the new start position
* @start: The value of the new start 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().
*
* MT safe.
*
* Returns: %TRUE if the event was handled. Flushing seeks will trigger a
* preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
*/
gboolean
gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
GstSeekFlags flags, GstSeekType start_type, gint64 start,
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, start_type, start, stop_type,
stop);
result = gst_element_send_event (element, event);
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 *klass;
gboolean res = FALSE;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (query != NULL, FALSE);
GST_TRACER_ELEMENT_QUERY_PRE (element, query);
klass = GST_ELEMENT_GET_CLASS (element);
if (klass->query) {
GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
GST_ELEMENT_NAME (element));
res = klass->query (element, query);
}
GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
return res;
}
static gboolean
gst_element_post_message_default (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_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)
{
GstElementClass *klass;
gboolean res = FALSE;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (message != NULL, FALSE);
GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
klass = GST_ELEMENT_GET_CLASS (element);
if (klass->post_message)
res = klass->post_message (element, message);
else
gst_message_unref (message);
GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
return res;
}
/**
* _gst_element_error_printf:
* @format: (allow-none): the printf-like format to use, or %NULL
*
* This function is only used internally by the gst_element_error() macro.
*
* Returns: (transfer full) (nullable): 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;
int len;
if (format == NULL)
return NULL;
if (format[0] == 0)
return NULL;
va_start (args, format);
len = __gst_vasprintf (&buffer, format, args);
va_end (args);
if (len < 0)
buffer = NULL;
return buffer;
}
/**
* gst_element_message_full_with_details:
* @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
* @structure:(transfer full): optional details structure
*
* 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.
*
* Since: 1.10
*/
void gst_element_message_full_with_details
(GstElement * element, GstMessageType type,
GQuark domain, gint code, gchar * text,
gchar * debug, const gchar * file, const gchar * function, gint line,
GstStructure * structure)
{
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_with_details (GST_OBJECT_CAST (element), gerror,
sent_debug, structure);
break;
case GST_MESSAGE_WARNING:
message =
gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
gerror, sent_debug, structure);
break;
case GST_MESSAGE_INFO:
message =
gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
sent_debug, structure);
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_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)
{
gst_element_message_full_with_details (element, type, domain, code, text,
debug, file, function, line, NULL);
}
/**
* 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_ELEMENT_IS_LOCKED_STATE (element);
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_ELEMENT_IS_LOCKED_STATE (element);
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_FLAG_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_FLAG_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 immediately */
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) {
gboolean signaled;
guint32 cookie;
/* 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 (timeout != GST_CLOCK_TIME_NONE) {
gint64 end_time;
/* make timeout absolute */
end_time = g_get_monotonic_time () + (timeout / 1000);
signaled = GST_STATE_WAIT_UNTIL (element, end_time);
} else {
GST_STATE_WAIT (element);
signaled = TRUE;
}
if (!signaled) {
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;
}
}
/* Not static because GstBin has manual state handling too */
void
_priv_gst_element_state_changed (GstElement * element, GstState oldstate,
GstState newstate, GstState pending)
{
GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
GstMessage *message;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"notifying about state-changed %s to %s (%s pending)",
gst_element_state_get_name (oldstate),
gst_element_state_get_name (newstate),
gst_element_state_get_name (pending));
if (klass->state_changed)
klass->state_changed (element, oldstate, newstate, pending);
message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
oldstate, newstate, pending);
gst_element_post_message (element, message);
}
/**
* 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.
*
* This function must be called with STATE_LOCK held.
*
* 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;
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));
_priv_gst_element_state_changed (element, old_state, old_next, pending);
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)
_priv_gst_element_state_changed (element, old_state, old_next,
GST_STATE_VOID_PENDING);
GST_STATE_BROADCAST (element);
return ret;
}
}
/**
* gst_element_lost_state:
* @element: a #GstElement the state is lost of
*
* 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. 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.
*/
void
gst_element_lost_state (GstElement * element)
{
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;
GST_OBJECT_UNLOCK (element);
_priv_gst_element_state_changed (element, new_state, new_state, new_state);
message = gst_message_new_async_start (GST_OBJECT_CAST (element));
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));
gst_element_post_message (element, message);
return;
}
}
/**
* 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 %GST_MESSAGE_ASYNC_DONE or
* %GST_MESSAGE_STATE_CHANGED 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);
GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
/* 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;
GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
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
* Stop the iterator if activating one pad failed, but only if that pad
* has not been removed from the element. */
static gboolean
activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
{
GstPad *pad = g_value_get_object (vpad);
gboolean cont = TRUE;
if (!gst_pad_set_active (pad, *active)) {
if (GST_PAD_PARENT (pad) != NULL) {
cont = FALSE;
g_value_set_boolean (ret, FALSE);
}
}
return cont;
}
/* returns false on error or early cutout 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) {