gstreamer/gst/gstbin.c
Wim Taymans 326d36b8d8 Added state change code.
Original commit message from CVS:
Added state change code.
Added/updated docs.
Added sink base class, make fakesink extend the base class.
Small cleanups in GstPipeline.
2005-03-28 14:54:33 +00:00

1319 lines
36 KiB
C

/* GStreamer
*
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2004 Wim Taymans <wim@fluendo.com>
*
* gstbin.c: GstBin container object and support code
*
* 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.
*
* MT safe.
*/
#include "gst_private.h"
#include "gstevent.h"
#include "gstbin.h"
#include "gstmarshal.h"
#include "gstxml.h"
#include "gstinfo.h"
#include "gsterror.h"
#include "gstscheduler.h"
#include "gstindex.h"
#include "gstutils.h"
GST_DEBUG_CATEGORY_STATIC (bin_debug);
#define GST_CAT_DEFAULT bin_debug
#define GST_LOG_BIN_CONTENTS(bin, text) GST_LOG_OBJECT ((bin), \
text ": %d elements: %u PLAYING, %u PAUSED, %u READY, %u NULL, own state: %s", \
(bin)->numchildren, (guint) (bin)->child_states[3], \
(guint) (bin)->child_states[2], (bin)->child_states[1], \
(bin)->child_states[0], gst_element_state_get_name (GST_STATE (bin)))
static GstElementDetails gst_bin_details = GST_ELEMENT_DETAILS ("Generic bin",
"Generic/Bin",
"Simple container object",
"Erik Walthinsen <omega@cse.ogi.edu>," "Wim Taymans <wim@fluendo.com>");
GType _gst_bin_type = 0;
static void gst_bin_dispose (GObject * object);
static GstElementStateReturn gst_bin_change_state (GstElement * element);
static GstElementStateReturn gst_bin_get_state (GstElement * element,
GstElementState * state, GstElementState * pending, GTimeVal * timeout);
static gboolean gst_bin_add_func (GstBin * bin, GstElement * element);
static gboolean gst_bin_remove_func (GstBin * bin, GstElement * element);
#ifndef GST_DISABLE_INDEX
static void gst_bin_set_index_func (GstElement * element, GstIndex * index);
#endif
static GstClock *gst_bin_get_clock_func (GstElement * element);
static void gst_bin_set_clock_func (GstElement * element, GstClock * clock);
static void gst_bin_set_manager (GstElement * element, GstPipeline * manager);
static void gst_bin_set_bus (GstElement * element, GstBus * bus);
static void gst_bin_set_scheduler (GstElement * element, GstScheduler * sched);
static gboolean gst_bin_send_event (GstElement * element, GstEvent * event);
#ifndef GST_DISABLE_LOADSAVE
static xmlNodePtr gst_bin_save_thyself (GstObject * object, xmlNodePtr parent);
static void gst_bin_restore_thyself (GstObject * object, xmlNodePtr self);
#endif
/* Bin signals and args */
enum
{
ELEMENT_ADDED,
ELEMENT_REMOVED,
LAST_SIGNAL
};
enum
{
ARG_0
/* FILL ME */
};
static void gst_bin_base_init (gpointer g_class);
static void gst_bin_class_init (GstBinClass * klass);
static void gst_bin_init (GstBin * bin);
static GstElementClass *parent_class = NULL;
static guint gst_bin_signals[LAST_SIGNAL] = { 0 };
/**
* gst_bin_get_type:
*
* Returns: the type of #GstBin
*/
GType
gst_bin_get_type (void)
{
if (!_gst_bin_type) {
static const GTypeInfo bin_info = {
sizeof (GstBinClass),
gst_bin_base_init,
NULL,
(GClassInitFunc) gst_bin_class_init,
NULL,
NULL,
sizeof (GstBin),
0,
(GInstanceInitFunc) gst_bin_init,
NULL
};
_gst_bin_type =
g_type_register_static (GST_TYPE_ELEMENT, "GstBin", &bin_info, 0);
GST_DEBUG_CATEGORY_INIT (bin_debug, "bin", GST_DEBUG_BOLD,
"debugging info for the 'bin' container element");
}
return _gst_bin_type;
}
static void
gst_bin_base_init (gpointer g_class)
{
GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
gst_element_class_set_details (gstelement_class, &gst_bin_details);
}
static void
gst_bin_class_init (GstBinClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
gst_bin_signals[ELEMENT_ADDED] =
g_signal_new ("element-added", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_added), NULL,
NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
gst_bin_signals[ELEMENT_REMOVED] =
g_signal_new ("element-removed", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_removed), NULL,
NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_bin_dispose);
#ifndef GST_DISABLE_LOADSAVE
gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_bin_save_thyself);
gstobject_class->restore_thyself =
GST_DEBUG_FUNCPTR (gst_bin_restore_thyself);
#endif
gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_bin_change_state);
gstelement_class->get_state = GST_DEBUG_FUNCPTR (gst_bin_get_state);
#ifndef GST_DISABLE_INDEX
gstelement_class->set_index = GST_DEBUG_FUNCPTR (gst_bin_set_index_func);
#endif
gstelement_class->get_clock = GST_DEBUG_FUNCPTR (gst_bin_get_clock_func);
gstelement_class->set_clock = GST_DEBUG_FUNCPTR (gst_bin_set_clock_func);
gstelement_class->set_manager = GST_DEBUG_FUNCPTR (gst_bin_set_manager);
gstelement_class->set_bus = GST_DEBUG_FUNCPTR (gst_bin_set_bus);
gstelement_class->set_scheduler = GST_DEBUG_FUNCPTR (gst_bin_set_scheduler);
gstelement_class->send_event = GST_DEBUG_FUNCPTR (gst_bin_send_event);
klass->add_element = GST_DEBUG_FUNCPTR (gst_bin_add_func);
klass->remove_element = GST_DEBUG_FUNCPTR (gst_bin_remove_func);
}
static void
gst_bin_init (GstBin * bin)
{
bin->numchildren = 0;
bin->children = NULL;
bin->children_cookie = 0;
}
/**
* gst_bin_new:
* @name: name of new bin
*
* Create a new bin with given name.
*
* Returns: new bin
*/
GstElement *
gst_bin_new (const gchar * name)
{
return gst_element_factory_make ("bin", name);
}
/* set the index on all elements in this bin
*
* MT safe
*/
#ifndef GST_DISABLE_INDEX
static void
gst_bin_set_index_func (GstElement * element, GstIndex * index)
{
GstBin *bin;
GList *children;
bin = GST_BIN (element);
GST_LOCK (bin);
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
gst_element_set_index (child, index);
}
GST_UNLOCK (bin);
}
#endif
/* set the clock on all elements in this bin
*
* MT safe
*/
static void
gst_bin_set_clock_func (GstElement * element, GstClock * clock)
{
GList *children;
GstBin *bin;
bin = GST_BIN (element);
GST_LOCK (bin);
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
gst_element_set_clock (child, clock);
}
GST_UNLOCK (bin);
}
/* get the clock for this bin by asking all of the children in this bin
*
* MT safe
*/
static GstClock *
gst_bin_get_clock_func (GstElement * element)
{
GstClock *result = NULL;
GstBin *bin;
GList *children;
bin = GST_BIN (element);
GST_LOCK (bin);
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
result = gst_element_get_clock (child);
if (result)
break;
}
GST_UNLOCK (bin);
return result;
}
/* set the bus on all of the children in this bin
*
* MT safe
*/
static void
gst_bin_set_bus (GstElement * element, GstBus * bus)
{
GList *children;
GstBin *bin;
bin = GST_BIN (element);
parent_class->set_bus (element, bus);
GST_LOCK (bin);
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
gst_element_set_bus (child, bus);
}
GST_UNLOCK (bin);
}
/* set the scheduler on all of the children in this bin
*
* MT safe
*/
static void
gst_bin_set_scheduler (GstElement * element, GstScheduler * sched)
{
GList *children;
GstBin *bin;
bin = GST_BIN (element);
parent_class->set_scheduler (element, sched);
GST_LOCK (bin);
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
gst_element_set_scheduler (child, sched);
}
GST_UNLOCK (bin);
}
/* set the manager on all of the children in this bin
*
* MT safe
*/
static void
gst_bin_set_manager (GstElement * element, GstPipeline * manager)
{
GstBin *bin = GST_BIN (element);
GList *kids;
GstElement *kid;
GST_ELEMENT_CLASS (parent_class)->set_manager (element, manager);
GST_LOCK (element);
for (kids = bin->children; kids != NULL; kids = kids->next) {
kid = GST_ELEMENT (kids->data);
gst_element_set_manager (kid, manager);
}
GST_UNLOCK (element);
}
/* add an element to this bin
*
* MT safe
*/
static gboolean
gst_bin_add_func (GstBin * bin, GstElement * element)
{
gchar *elem_name;
/* we obviously can't add ourself to ourself */
if (G_UNLIKELY (GST_ELEMENT_CAST (element) == GST_ELEMENT_CAST (bin)))
goto adding_itself;
/* get the element name to make sure it is unique in this bin, FIXME, another
* thread can change the name after the unlock. */
GST_LOCK (element);
elem_name = g_strdup (GST_ELEMENT_NAME (element));
GST_UNLOCK (element);
GST_LOCK (bin);
/* then check to see if the element's name is already taken in the bin,
* we can safely take the lock here. This check is probably bogus because
* you can safely change the element name after adding it to the bin. */
if (G_UNLIKELY (gst_object_check_uniqueness (bin->children,
elem_name) == FALSE))
goto duplicate_name;
/* set the element's parent and add the element to the bin's list of children */
if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (element),
GST_OBJECT_CAST (bin))))
goto had_parent;
bin->children = g_list_prepend (bin->children, element);
bin->numchildren++;
bin->children_cookie++;
gst_element_set_manager (element, GST_ELEMENT (bin)->manager);
gst_element_set_bus (element, GST_ELEMENT (bin)->bus);
gst_element_set_scheduler (element, GST_ELEMENT_SCHEDULER (bin));
GST_UNLOCK (bin);
GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "added element \"%s\"",
elem_name);
g_free (elem_name);
g_signal_emit (G_OBJECT (bin), gst_bin_signals[ELEMENT_ADDED], 0, element);
return TRUE;
/* ERROR handling here */
adding_itself:
{
GST_LOCK (bin);
g_warning ("Cannot add bin %s to itself", GST_ELEMENT_NAME (bin));
GST_UNLOCK (bin);
return FALSE;
}
duplicate_name:
{
g_warning ("Name %s is not unique in bin %s, not adding",
elem_name, GST_ELEMENT_NAME (bin));
GST_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
had_parent:
{
g_warning ("Element %s already has parent", elem_name);
GST_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
}
/**
* gst_bin_add:
* @bin: #GstBin to add element to
* @element: #GstElement to add to bin
*
* Adds the given element to the bin. Sets the element's parent, and thus
* takes ownership of the element. An element can only be added to one bin.
*
* Returns: TRUE if the element could be added, FALSE on wrong parameters or
* the bin does not want to accept the element.
*
* MT safe.
*/
gboolean
gst_bin_add (GstBin * bin, GstElement * element)
{
GstBinClass *bclass;
gboolean result;
g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
bclass = GST_BIN_GET_CLASS (bin);
if (G_UNLIKELY (bclass->add_element == NULL))
goto no_function;
GST_CAT_DEBUG (GST_CAT_PARENTAGE, "adding element %s to bin %s",
GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
result = bclass->add_element (bin, element);
return result;
/* ERROR handling */
no_function:
{
g_warning ("adding elements to bin %s is not supported",
GST_ELEMENT_NAME (bin));
return FALSE;
}
}
/* remove an element from the bin
*
* MT safe
*/
static gboolean
gst_bin_remove_func (GstBin * bin, GstElement * element)
{
gchar *elem_name;
/* grab element name so we can print it */
GST_LOCK (element);
elem_name = g_strdup (GST_ELEMENT_NAME (element));
GST_UNLOCK (element);
GST_LOCK (bin);
/* the element must be in the bin's list of children */
if (G_UNLIKELY (g_list_find (bin->children, element) == NULL))
goto not_in_bin;
/* now remove the element from the list of elements */
bin->children = g_list_remove (bin->children, element);
bin->numchildren--;
bin->children_cookie++;
GST_UNLOCK (bin);
GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
elem_name);
g_free (elem_name);
gst_element_set_manager (element, NULL);
gst_element_set_bus (element, NULL);
gst_element_set_scheduler (element, NULL);
/* we ref here because after the _unparent() the element can be disposed
* and we still need it to fire a signal. */
gst_object_ref (GST_OBJECT_CAST (element));
gst_object_unparent (GST_OBJECT_CAST (element));
g_signal_emit (G_OBJECT (bin), gst_bin_signals[ELEMENT_REMOVED], 0, element);
/* element is really out of our control now */
gst_object_unref (GST_OBJECT_CAST (element));
return TRUE;
/* ERROR handling */
not_in_bin:
{
g_warning ("Element %s is not in bin %s", elem_name,
GST_ELEMENT_NAME (bin));
GST_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
}
/**
* gst_bin_remove:
* @bin: #GstBin to remove element from
* @element: #GstElement to remove
*
* Remove the element from its associated bin, unparenting it as well.
* Unparenting the element means that the element will be dereferenced,
* so if the bin holds the only reference to the element, the element
* will be freed in the process of removing it from the bin. If you
* want the element to still exist after removing, you need to call
* #gst_object_ref before removing it from the bin.
*
* Returns: TRUE if the element could be removed, FALSE on wrong parameters or
* the bin does not want to remove the element.
*
* MT safe.
*/
gboolean
gst_bin_remove (GstBin * bin, GstElement * element)
{
GstBinClass *bclass;
gboolean result;
g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
bclass = GST_BIN_GET_CLASS (bin);
if (G_UNLIKELY (bclass->remove_element == NULL))
goto no_function;
GST_CAT_DEBUG (GST_CAT_PARENTAGE, "removing element %s from bin %s",
GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
result = bclass->remove_element (bin, element);
return result;
/* ERROR handling */
no_function:
{
g_warning ("removing elements from bin %s is not supported",
GST_ELEMENT_NAME (bin));
return FALSE;
}
}
static GstIteratorItem
iterate_child (GstIterator * it, GstElement * child)
{
gst_object_ref (GST_OBJECT (child));
return GST_ITERATOR_ITEM_PASS;
}
/**
* gst_bin_iterate_elements:
* @bin: #Gstbin to iterate the elements of
*
* Get an iterator for the elements in this bin.
* Each element will have its refcount increased, so unref
* after usage.
*
* Returns: a #GstIterator of #GstElements. gst_iterator_free after
* use. returns NULL when passing bad parameters.
*
* MT safe.
*/
GstIterator *
gst_bin_iterate_elements (GstBin * bin)
{
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
GST_LOCK (bin);
/* add ref because the iterator refs the bin. When the iterator
* is freed it will unref the bin again using the provided dispose
* function. */
gst_object_ref (GST_OBJECT (bin));
result = gst_iterator_new_list (GST_GET_LOCK (bin),
&bin->children_cookie,
&bin->children,
bin,
(GstIteratorItemFunction) iterate_child,
(GstIteratorDisposeFunction) gst_object_unref);
GST_UNLOCK (bin);
return result;
}
static GstIteratorItem
iterate_child_recurse (GstIterator * it, GstElement * child)
{
gst_object_ref (GST_OBJECT (child));
if (GST_IS_BIN (child)) {
GstIterator *other = gst_bin_iterate_recurse (GST_BIN (child));
gst_iterator_push (it, other);
}
return GST_ITERATOR_ITEM_PASS;
}
/**
* gst_bin_iterate_recurse:
* @bin: #Gstbin to iterate the elements of
*
* Get an iterator for the elements in this bin.
* Each element will have its refcount increased, so unref
* after usage. This iterator recurses into GstBin children.
*
* Returns: a #GstIterator of #GstElements. gst_iterator_free after
* use. returns NULL when passing bad parameters.
*
* MT safe.
*/
GstIterator *
gst_bin_iterate_recurse (GstBin * bin)
{
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
GST_LOCK (bin);
/* add ref because the iterator refs the bin. When the iterator
* is freed it will unref the bin again using the provided dispose
* function. */
gst_object_ref (GST_OBJECT (bin));
result = gst_iterator_new_list (GST_GET_LOCK (bin),
&bin->children_cookie,
&bin->children,
bin,
(GstIteratorItemFunction) iterate_child_recurse,
(GstIteratorDisposeFunction) gst_object_unref);
GST_UNLOCK (bin);
return result;
}
/* returns 0 if the element is a sink, this is made so that
* we can use this function as a filter
*
* MT safe
*/
static gint
bin_element_is_sink (GstElement * child, GstBin * bin)
{
gint ret = 1;
/* we lock the child here for the remainder of the function to
* get its pads and name safely. */
GST_LOCK (child);
/* check if this is a sink element, these are the elements
* without (linked) source pads. */
if (child->numsrcpads == 0) {
/* shortcut */
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
"adding child %s as sink", GST_OBJECT_NAME (child));
ret = 0;
} else {
/* loop over all pads, try to figure out if this element
* is a sink because it has no linked source pads */
GList *pads;
gboolean connected_src = FALSE;
for (pads = child->srcpads; pads; pads = g_list_next (pads)) {
GstPad *peer;
peer = gst_pad_get_peer (GST_PAD_CAST (pads->data));
if (peer) {
GstElement *parent;
parent = gst_pad_get_parent (peer);
if (parent) {
GstObject *grandparent;
grandparent = gst_object_get_parent (GST_OBJECT_CAST (parent));
if (grandparent == GST_OBJECT_CAST (bin)) {
connected_src = TRUE;
}
if (grandparent) {
gst_object_unref (GST_OBJECT_CAST (grandparent));
}
gst_object_unref (GST_OBJECT_CAST (parent));
}
gst_object_unref (GST_OBJECT_CAST (peer));
if (connected_src) {
break;
}
}
}
if (connected_src) {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
"not adding child %s as sink: linked source pads",
GST_OBJECT_NAME (child));
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
"adding child %s as sink since it has unlinked source pads in this bin",
GST_OBJECT_NAME (child));
ret = 0;
}
}
GST_UNLOCK (child);
/* we did not find the element, need to release the ref
* added by the iterator */
if (ret == 1)
gst_object_unref (GST_OBJECT (child));
return ret;
}
/**
* gst_bin_iterate_sinks:
* @bin: #Gstbin to iterate on
*
* Get an iterator for the sink elements in this bin.
* Each element will have its refcount increased, so unref
* after usage.
*
* The sink elements are those without any linked srcpads.
*
* Returns: a #GstIterator of #GstElements. gst_iterator_free after use.
*
* MT safe.
*/
GstIterator *
gst_bin_iterate_sinks (GstBin * bin)
{
GstIterator *children;
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
children = gst_bin_iterate_elements (bin);
result = gst_iterator_filter (children,
(GCompareFunc) bin_element_is_sink, bin);
return result;
}
/* this functions loops over all children, as soon as one does
* not return SUCCESS, we return that value.
*
* MT safe
*/
static GstElementStateReturn
gst_bin_get_state (GstElement * element, GstElementState * state,
GstElementState * pending, GTimeVal * timeout)
{
GstBin *bin = GST_BIN (element);
GstElementStateReturn ret;
GList *children;
guint32 children_cookie;
/* we cannot take the state lock yet as we might block when querying
* the children, holding the lock too long for no reason. */
/* next we poll all children for their state to see if one of them
* is still busy with its state change. */
GST_LOCK (bin);
restart:
ret = GST_STATE_SUCCESS;
children = bin->children;
children_cookie = bin->children_cookie;
while (children) {
GstElement *child = GST_ELEMENT_CAST (children->data);
gst_object_ref (GST_OBJECT_CAST (child));
GST_UNLOCK (bin);
/* ret is ASYNC if some child is still performing the state change */
ret = gst_element_get_state (child, NULL, NULL, timeout);
gst_object_unref (GST_OBJECT_CAST (child));
if (ret != GST_STATE_SUCCESS) {
/* some child is still busy or in error, we can report that
* right away. */
goto done;
}
/* now grab the lock to iterate to the next child */
GST_LOCK (bin);
if (G_UNLIKELY (children_cookie != bin->children_cookie))
/* child added/removed during state change, restart */
goto restart;
children = g_list_next (children);
}
GST_UNLOCK (bin);
done:
/* now we can take the state lock */
GST_STATE_LOCK (bin);
switch (ret) {
case GST_STATE_SUCCESS:
/* we can commit the state */
gst_element_commit_state (element);
break;
case GST_STATE_FAILURE:
/* some element failed, abort the state change */
gst_element_abort_state (element);
break;
default:
/* other cases are just passed along */
break;
}
/* and report the state if needed */
if (state)
*state = GST_STATE (element);
if (pending)
*pending = GST_STATE_PENDING (element);
GST_STATE_UNLOCK (bin);
return ret;
}
/* this function is called with the STATE_LOCK held. It works
* as follows:
*
* 1) put all sink elements on the queue.
* 2) change state of elements in queue, put linked elements to queue.
* 3) while queue not empty goto 2)
*
* This will effectively change the state of all elements in the bin
* from the sinks to the sources. We have to change the states this
* way so that when a source element pushes data, the downstream element
* is in the right state to receive the data.
*
* MT safe.
*/
static GstElementStateReturn
gst_bin_change_state (GstElement * element)
{
GstBin *bin;
GstElementStateReturn ret;
GstElementState old_state, pending;
gboolean have_async = FALSE;
GList *children;
guint32 children_cookie;
GQueue *elem_queue; /* list of elements waiting for a state change */
bin = GST_BIN (element);
/* we don't need to take the STATE_LOCK, it is already taken */
old_state = GST_STATE (element);
pending = GST_STATE_PENDING (element);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"changing state of children from %s to %s",
gst_element_state_get_name (old_state),
gst_element_state_get_name (pending));
if (pending == GST_STATE_VOID_PENDING)
return GST_STATE_SUCCESS;
/* all elements added to this queue should have their refcount
* incremented */
elem_queue = g_queue_new ();
/* first step, find all sink elements, these are the elements
* without (linked) source pads. */
GST_LOCK (bin);
restart:
children = bin->children;
children_cookie = bin->children_cookie;
while (children) {
GstElement *child = GST_ELEMENT_CAST (children->data);
gst_object_ref (GST_OBJECT_CAST (child));
GST_UNLOCK (bin);
if (bin_element_is_sink (child, bin) == 0) {
/* this also keeps the refcount on the element, note that
* the _is_sink function unrefs the element when it is not
* a sink. */
g_queue_push_tail (elem_queue, child);
}
GST_LOCK (bin);
if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
/* undo what we had */
g_queue_foreach (elem_queue, (GFunc) gst_object_unref, NULL);
while (g_queue_pop_head (elem_queue));
goto restart;
}
children = g_list_next (children);
}
GST_UNLOCK (bin);
/* second step, change state of elements in the queue */
while (!g_queue_is_empty (elem_queue)) {
GstElement *qelement = g_queue_pop_head (elem_queue);
GList *pads;
gboolean locked;
/* queue all elements connected to the sinkpads of this element */
GST_LOCK (qelement);
pads = qelement->sinkpads;
while (pads) {
GstPad *pad = GST_PAD_CAST (pads->data);
GstPad *peer;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"found sinkpad %s:%s", GST_DEBUG_PAD_NAME (pad));
peer = gst_pad_get_peer (pad);
if (peer) {
GstObject *peer_elem;
peer_elem = gst_object_get_parent (GST_OBJECT_CAST (peer));
if (peer_elem) {
GstObject *parent;
/* see if this element is in the bin we are currently handling */
parent = gst_object_get_parent (GST_OBJECT_CAST (peer_elem));
if (parent && parent == GST_OBJECT_CAST (bin)) {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"adding element %s to queue", GST_ELEMENT_NAME (peer_elem));
/* was reffed before pushing on the queue by the
* gst_object_get_parent() call we used to get the element. */
g_queue_push_tail (elem_queue, peer_elem);
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"not adding element %s to queue, it is in another bin",
GST_ELEMENT_NAME (peer_elem));
}
if (parent) {
gst_object_unref (GST_OBJECT_CAST (parent));
}
}
gst_object_unref (GST_OBJECT_CAST (peer));
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"pad %s:%s does not have a peer", GST_DEBUG_PAD_NAME (pad));
}
pads = g_list_next (pads);
}
/* peel off the locked flag and release the element lock */
locked = GST_FLAG_IS_SET (qelement, GST_ELEMENT_LOCKED_STATE);
GST_UNLOCK (qelement);
if (G_UNLIKELY (locked))
goto next_element;
qelement->base_time = element->base_time;
ret = gst_element_set_state (qelement, pending);
switch (ret) {
case GST_STATE_SUCCESS:
GST_CAT_DEBUG (GST_CAT_STATES,
"child '%s' changed state to %d(%s) successfully",
GST_ELEMENT_NAME (qelement), pending,
gst_element_state_get_name (pending));
break;
case GST_STATE_ASYNC:
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"child '%s' is changing state asynchronously",
GST_ELEMENT_NAME (qelement));
have_async = TRUE;
break;
case GST_STATE_FAILURE:
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"child '%s' failed to go to state %d(%s)",
GST_ELEMENT_NAME (qelement),
pending, gst_element_state_get_name (pending));
ret = GST_STATE_FAILURE;
/* release refcount of element we popped off the queue */
gst_object_unref (GST_OBJECT (qelement));
goto exit;
default:
g_assert_not_reached ();
break;
}
next_element:
gst_object_unref (GST_OBJECT (qelement));
}
if (have_async) {
ret = GST_STATE_ASYNC;
} else {
if (parent_class->change_state) {
ret = parent_class->change_state (element);
} else {
ret = GST_STATE_SUCCESS;
}
if (ret == GST_STATE_SUCCESS) {
/* we can commit the state change now */
gst_element_commit_state (element);
}
}
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"done changing bin's state from %s to %s, now in %s",
gst_element_state_get_name (old_state),
gst_element_state_get_name (pending),
gst_element_state_get_name (GST_STATE (element)));
exit:
/* release refcounts in queue, should normally be empty */
g_queue_foreach (elem_queue, (GFunc) gst_object_unref, NULL);
g_queue_free (elem_queue);
return ret;
}
static void
gst_bin_dispose (GObject * object)
{
GstBin *bin = GST_BIN (object);
GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
/* ref to not hit 0 again */
gst_object_ref (GST_OBJECT (object));
while (bin->children) {
gst_bin_remove (bin, GST_ELEMENT (bin->children->data));
}
GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose no children");
g_assert (bin->children == NULL);
g_assert (bin->numchildren == 0);
G_OBJECT_CLASS (parent_class)->dispose (object);
}
/*
* This function is a utility event handler for seek events.
* It will send the event to all sinks.
* Applications are free to override this behaviour and
* implement their own seek handler, but this will work for
* pretty much all cases in practice.
*/
static gboolean
gst_bin_send_event (GstElement * element, GstEvent * event)
{
GstBin *bin = GST_BIN (element);
GstIterator *iter;
gboolean res = TRUE;
gboolean done = FALSE;
iter = gst_bin_iterate_sinks (bin);
GST_DEBUG_OBJECT (bin, "Sending event to sink children");
while (!done) {
gpointer data;
switch (gst_iterator_next (iter, &data)) {
case GST_ITERATOR_OK:
{
GstElement *sink;
gst_event_ref (event);
sink = GST_ELEMENT_CAST (data);
res &= gst_element_send_event (sink, event);
gst_object_unref (GST_OBJECT (sink));
break;
}
case GST_ITERATOR_RESYNC:
gst_iterator_resync (iter);
res = TRUE;
break;
default:
case GST_ITERATOR_DONE:
done = TRUE;
break;
}
}
gst_iterator_free (iter);
gst_event_unref (event);
return res;
}
static gint
compare_name (GstElement * element, const gchar * name)
{
gint eq;
GST_LOCK (element);
eq = strcmp (GST_ELEMENT_NAME (element), name) == 0;
GST_UNLOCK (element);
if (eq != 0) {
gst_object_unref (GST_OBJECT (element));
}
return eq;
}
/**
* gst_bin_get_by_name:
* @bin: #Gstbin to search
* @name: the element name to search for
*
* Get the element with the given name from this bin. This
* function recurses into subbins.
*
* Returns: the element with the given name. Returns NULL if the
* element is not found or when bad parameters were given. Unref after
* usage.
*
* MT safe.
*/
GstElement *
gst_bin_get_by_name (GstBin * bin, const gchar * name)
{
GstIterator *children;
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
children = gst_bin_iterate_recurse (bin);
result = gst_iterator_find_custom (children,
(GCompareFunc) compare_name, (gpointer) name);
gst_iterator_free (children);
return GST_ELEMENT_CAST (result);
}
/**
* gst_bin_get_by_name_recurse_up:
* @bin: #Gstbin to search
* @name: the element name to search for
*
* Get the element with the given name from this bin. If the
* element is not found, a recursion is performed on the parent bin.
*
* Returns: the element with the given name or NULL when the element
* was not found or bad parameters were given. Unref after usage.
*
* MT safe.
*/
GstElement *
gst_bin_get_by_name_recurse_up (GstBin * bin, const gchar * name)
{
GstElement *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
g_return_val_if_fail (name != NULL, NULL);
result = gst_bin_get_by_name (bin, name);
if (!result) {
GstObject *parent;
parent = gst_object_get_parent (GST_OBJECT_CAST (bin));
if (parent) {
if (GST_IS_BIN (parent)) {
result = gst_bin_get_by_name_recurse_up (GST_BIN_CAST (parent), name);
}
gst_object_unref (parent);
}
}
return result;
}
static gint
compare_interface (GstElement * element, gpointer interface)
{
gint ret;
if (G_TYPE_CHECK_INSTANCE_TYPE (element, GPOINTER_TO_INT (interface))) {
ret = 0;
} else {
/* we did not find the element, need to release the ref
* added by the iterator */
gst_object_unref (GST_OBJECT (element));
ret = 1;
}
return ret;
}
/**
* gst_bin_get_by_interface:
* @bin: bin to find element in
* @interface: interface to be implemented by interface
*
* Looks for the first element inside the bin that implements the given
* interface. If such an element is found, it returns the element. You can
* cast this element to the given interface afterwards.
* If you want all elements that implement the interface, use
* gst_bin_iterate_all_by_interface(). The function recurses bins inside bins.
*
* Returns: An element inside the bin implementing the interface. Unref after
* usage.
*
* MT safe.
*/
GstElement *
gst_bin_get_by_interface (GstBin * bin, GType interface)
{
GstIterator *children;
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
children = gst_bin_iterate_recurse (bin);
result = gst_iterator_find_custom (children, (GCompareFunc) compare_interface,
GINT_TO_POINTER (interface));
gst_iterator_free (children);
return GST_ELEMENT_CAST (result);
}
/**
* gst_bin_get_all_by_interface:
* @bin: bin to find elements in
* @interface: interface to be implemented by interface
*
* Looks for all elements inside the bin that implements the given
* interface. You can safely cast all returned elements to the given interface.
* The function recurses bins inside bins. The iterator will return a series
* of #GstElement that should be unreffed after usage.
*
* Returns: An iterator for the elements inside the bin implementing the interface.
*
* MT safe.
*/
GstIterator *
gst_bin_iterate_all_by_interface (GstBin * bin, GType interface)
{
GstIterator *children;
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
children = gst_bin_iterate_recurse (bin);
result = gst_iterator_filter (children, (GCompareFunc) compare_interface,
GINT_TO_POINTER (interface));
return result;
}
#ifndef GST_DISABLE_LOADSAVE
static xmlNodePtr
gst_bin_save_thyself (GstObject * object, xmlNodePtr parent)
{
GstBin *bin = GST_BIN (object);
xmlNodePtr childlist, elementnode;
GList *children;
GstElement *child;
if (GST_OBJECT_CLASS (parent_class)->save_thyself)
GST_OBJECT_CLASS (parent_class)->save_thyself (GST_OBJECT (bin), parent);
childlist = xmlNewChild (parent, NULL, "children", NULL);
GST_CAT_INFO (GST_CAT_XML, "[%s]: saving %d children",
GST_ELEMENT_NAME (bin), bin->numchildren);
children = bin->children;
while (children) {
child = GST_ELEMENT (children->data);
elementnode = xmlNewChild (childlist, NULL, "element", NULL);
gst_object_save_thyself (GST_OBJECT (child), elementnode);
children = g_list_next (children);
}
return childlist;
}
static void
gst_bin_restore_thyself (GstObject * object, xmlNodePtr self)
{
GstBin *bin = GST_BIN (object);
xmlNodePtr field = self->xmlChildrenNode;
xmlNodePtr childlist;
while (field) {
if (!strcmp (field->name, "children")) {
GST_CAT_INFO (GST_CAT_XML, "[%s]: loading children",
GST_ELEMENT_NAME (object));
childlist = field->xmlChildrenNode;
while (childlist) {
if (!strcmp (childlist->name, "element")) {
GstElement *element =
gst_xml_make_element (childlist, GST_OBJECT (bin));
/* it had to be parented to find the pads, now we ref and unparent so
* we can add it to the bin */
gst_object_ref (GST_OBJECT (element));
gst_object_unparent (GST_OBJECT (element));
gst_bin_add (bin, element);
}
childlist = childlist->next;
}
}
field = field->next;
}
if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
(GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
}
#endif /* GST_DISABLE_LOADSAVE */