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gstreamer/gst/gstbin.c
Wim Taymans 75b997ad55 docs/design/part-synchronisation.txt: Small addition. 
Original commit message from CVS:
* docs/design/part-synchronisation.txt:
Small addition.
* gst/gstbin.c: (gst_bin_query):
* plugins/elements/gstqueue.c: (apply_segment):
Improve debugging.
* gst/gstmessage.h:
Improve docs.
2007-05-21 12:05:14 +00:00

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/* 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.
*/
/**
* SECTION:gstbin
* @short_description: Base class and element that can contain other elements
*
* #GstBin is an element that can contain other #GstElement, allowing them to be
* managed as a group.
* Pads from the child elements can be ghosted to the bin, see #GstGhostPad.
* This makes the bin look like any other elements and enables creation of
* higher-level abstraction elements.
*
* A new #GstBin is created with gst_bin_new(). Use a #GstPipeline instead if you
* want to create a toplevel bin because a normal bin doesn't have a bus or
* handle clock distribution of its own.
*
* After the bin has been created you will typically add elements to it with
* gst_bin_add(). You can remove elements with gst_bin_remove().
*
* An element can be retrieved from a bin with gst_bin_get_by_name(), using the
* elements name. gst_bin_get_by_name_recurse_up() is mainly used for internal
* purposes and will query the parent bins when the element is not found in the
* current bin.
*
* An iterator of elements in a bin can be retrieved with
* gst_bin_iterate_elements(). Various other iterators exist to retrieve the
* elements in a bin.
*
* gst_object_unref() is used to drop your reference to the bin.
*
* The <link linkend="GstBin-element-added">element-added</link> signal is
* fired whenever a new element is added to the bin. Likewise the <link
* linkend="GstBin-element-removed">element-removed</link> signal is fired
* whenever an element is removed from the bin.
*
* <refsect2><title>Notes</title>
* <para>
* A #GstBin internally intercepts every #GstMessage posted by its children and
* implements the following default behaviour for each of them:
* <variablelist>
* <varlistentry>
* <term>GST_MESSAGE_EOS</term>
* <listitem><para>This message is only posted by sinks in the PLAYING
* state. If all sinks posted the EOS message, this bin will post and EOS
* message upwards.</para></listitem>
* </varlistentry>
* <varlistentry>
* <term>GST_MESSAGE_SEGMENT_START</term>
* <listitem><para>just collected and never forwarded upwards.
* The messages are used to decide when all elements have completed playback
* of their segment.</para></listitem>
* </varlistentry>
* <varlistentry>
* <term>GST_MESSAGE_SEGMENT_DONE</term>
* <listitem><para> Is posted by #GstBin when all elements that posted
* a SEGMENT_START have posted a SEGMENT_DONE.</para></listitem>
* </varlistentry>
* <varlistentry>
* <term>GST_MESSAGE_DURATION</term>
* <listitem><para> Is posted by an element that detected a change
* in the stream duration. The default bin behaviour is to clear any
* cached duration values so that the next duration query will perform
* a full duration recalculation. The duration change is posted to the
* application so that it can refetch the new duration with a duration
* query.
* </para></listitem>
* </varlistentry>
* <varlistentry>
* <term>GST_MESSAGE_CLOCK_LOST</term>
* <listitem><para> This message is posted by an element when it
* can no longer provide a clock. The default bin behaviour is to
* check if the lost clock was the one provided by the bin. If so and
* the bin is currently in the PLAYING state, the message is forwarded to
* the bin parent.
* This message is also generated when a clock provider is removed from
* the bin. If this message is received by the application, it should
* PAUSE the pipeline and set it back to PLAYING to force a new clock
* distribution.
* </para></listitem>
* </varlistentry>
* <varlistentry>
* <term>GST_MESSAGE_CLOCK_PROVIDE</term>
* <listitem><para> This message is generated when an element
* can provide a clock. This mostly happens when a new clock
* provider is added to the bin. The default behaviour of the bin is to
* mark the currently selected clock as dirty, which will perform a clock
* recalculation the next time the bin is asked to provide a clock.
* This message is never sent tot the application but is forwarded to
* the parent of the bin.
* </para></listitem>
* </varlistentry>
* <varlistentry>
* <term>OTHERS</term>
* <listitem><para> posted upwards.</para></listitem>
* </varlistentry>
* </variablelist>
*
*
* A #GstBin implements the following default behaviour for answering to a
* #GstQuery:
* <variablelist>
* <varlistentry>
* <term>GST_QUERY_DURATION</term>
* <listitem><para>If the query has been asked before with the same format
* and the bin is a toplevel bin (ie. has no parent),
* use the cached previous value. If no previous value was cached, the
* query is sent to all sink elements in the bin and the MAXIMUM of all
* values is returned. If the bin is a toplevel bin the value is cached.
* If no sinks are available in the bin, the query fails.
* </para></listitem>
* </varlistentry>
* <varlistentry>
* <term>GST_QUERY_POSITION</term>
* <listitem><para>The query is sent to all sink elements in the bin and the
* MAXIMUM of all values is returned. If no sinks are available in the bin,
* the query fails.
* </para></listitem>
* </varlistentry>
* <varlistentry>
* <term>OTHERS</term>
* <listitem><para>the query is forwarded to all sink elements, the result
* of the first sink that answers the query successfully is returned. If no
* sink is in the bin, the query fails.</para></listitem>
* </varlistentry>
* </variablelist>
*
* A #GstBin will by default forward any event sent to it to all sink elements.
* If all the sinks return TRUE, the bin will also return TRUE, else FALSE is
* returned. If no sinks are in the bin, the event handler will return TRUE.
*
* </para>
* </refsect2>
*
* Last reviewed on 2006-04-28 (0.10.6)
*/
#include "gst_private.h"
#include "gstevent.h"
#include "gstbin.h"
#include "gstmarshal.h"
#include "gstxml.h"
#include "gstinfo.h"
#include "gsterror.h"
#include "gstindex.h"
#include "gstindexfactory.h"
#include "gstutils.h"
#include "gstchildproxy.h"
/* enable for DURATION caching.
* FIXME currently too many elements don't update
* their duration when it changes so we return inaccurate values. */
#undef DURATION_CACHING
/* latency is by default disabled for non CVS for now.
* live-preroll and no-live-preroll in the environment var GST_COMPAT
* to enables or disable it respectively.
*/
#if GST_VERSION_NANO == 1
static gboolean enable_latency = TRUE;
#else
static gboolean enable_latency = FALSE;
#endif
GST_DEBUG_CATEGORY_STATIC (bin_debug);
#define GST_CAT_DEFAULT bin_debug
static const 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>");
static void gst_bin_dispose (GObject * object);
static GstStateChangeReturn gst_bin_change_state_func (GstElement * element,
GstStateChange transition);
static GstStateChangeReturn gst_bin_get_state_func (GstElement * element,
GstState * state, GstState * pending, GstClockTime timeout);
static void bin_handle_async_done (GstBin * bin, GstMessage ** message);
static void bin_push_state_continue (GstBin * bin);
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_provide_clock_func (GstElement * element);
static gboolean gst_bin_set_clock_func (GstElement * element, GstClock * clock);
static void gst_bin_handle_message_func (GstBin * bin, GstMessage * message);
static gboolean gst_bin_send_event (GstElement * element, GstEvent * event);
static GstBusSyncReply bin_bus_handler (GstBus * bus,
GstMessage * message, GstBin * bin);
static gboolean gst_bin_query (GstElement * element, GstQuery * query);
#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
static void bin_remove_messages (GstBin * bin, GstObject * src,
GstMessageType types);
static void gst_bin_continue_func (GstBin * child, gpointer data);
static gint bin_element_is_sink (GstElement * child, GstBin * bin);
static gint bin_element_is_src (GstElement * child, GstBin * bin);
static GstIterator *gst_bin_sort_iterator_new (GstBin * bin);
/* Bin signals and properties */
enum
{
ELEMENT_ADDED,
ELEMENT_REMOVED,
LAST_SIGNAL
};
enum
{
PROP_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 void gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data);
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)
{
static GType gst_bin_type = 0;
const gchar *compat;
if (G_UNLIKELY (gst_bin_type == 0)) {
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
};
static const GInterfaceInfo child_proxy_info = {
gst_bin_child_proxy_init,
NULL,
NULL
};
gst_bin_type =
g_type_register_static (GST_TYPE_ELEMENT, "GstBin", &bin_info, 0);
g_type_add_interface_static (gst_bin_type, GST_TYPE_CHILD_PROXY,
&child_proxy_info);
GST_DEBUG_CATEGORY_INIT (bin_debug, "bin", GST_DEBUG_BOLD,
"debugging info for the 'bin' container element");
/* compatibility stuff */
compat = g_getenv ("GST_COMPAT");
if (compat != NULL) {
if (strstr (compat, "no-live-preroll"))
enable_latency = FALSE;
else if (strstr (compat, "live-preroll"))
enable_latency = TRUE;
}
}
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 GstObject *
gst_bin_child_proxy_get_child_by_index (GstChildProxy * child_proxy,
guint index)
{
GstObject *res;
GstBin *bin;
bin = GST_BIN_CAST (child_proxy);
GST_OBJECT_LOCK (bin);
if ((res = g_list_nth_data (bin->children, index)))
gst_object_ref (res);
GST_OBJECT_UNLOCK (bin);
return res;
}
guint
gst_bin_child_proxy_get_children_count (GstChildProxy * child_proxy)
{
guint num;
GstBin *bin;
bin = GST_BIN_CAST (child_proxy);
GST_OBJECT_LOCK (bin);
num = bin->numchildren;
GST_OBJECT_UNLOCK (bin);
return num;
}
static void
gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data)
{
GstChildProxyInterface *iface = g_iface;
iface->get_children_count = gst_bin_child_proxy_get_children_count;
iface->get_child_by_index = gst_bin_child_proxy_get_child_by_index;
}
static void
gst_bin_class_init (GstBinClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstElementClass *gstelement_class;
GError *err;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
parent_class = g_type_class_peek_parent (klass);
/**
* GstBin::element-added:
* @bin: the #GstBin
* @element: the #GstElement that was added to the bin
*
* Will be emitted after the element was added to the bin.
*/
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);
/**
* GstBin::element-removed:
* @bin: the #GstBin
* @element: the #GstElement that was removed from the bin
*
* Will be emitted after the element was removed from the bin.
*/
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_func);
gstelement_class->get_state = GST_DEBUG_FUNCPTR (gst_bin_get_state_func);
#ifndef GST_DISABLE_INDEX
gstelement_class->set_index = GST_DEBUG_FUNCPTR (gst_bin_set_index_func);
#endif
gstelement_class->provide_clock =
GST_DEBUG_FUNCPTR (gst_bin_provide_clock_func);
gstelement_class->set_clock = GST_DEBUG_FUNCPTR (gst_bin_set_clock_func);
gstelement_class->send_event = GST_DEBUG_FUNCPTR (gst_bin_send_event);
gstelement_class->query = GST_DEBUG_FUNCPTR (gst_bin_query);
klass->add_element = GST_DEBUG_FUNCPTR (gst_bin_add_func);
klass->remove_element = GST_DEBUG_FUNCPTR (gst_bin_remove_func);
klass->handle_message = GST_DEBUG_FUNCPTR (gst_bin_handle_message_func);
GST_DEBUG ("creating bin thread pool");
err = NULL;
klass->pool =
g_thread_pool_new ((GFunc) gst_bin_continue_func, NULL, -1, FALSE, &err);
if (err != NULL) {
g_critical ("could alloc threadpool %s", err->message);
}
}
static void
gst_bin_init (GstBin * bin)
{
GstBus *bus;
bin->numchildren = 0;
bin->children = NULL;
bin->children_cookie = 0;
bin->messages = NULL;
bin->provided_clock = NULL;
bin->state_dirty = FALSE;
bin->clock_dirty = FALSE;
/* Set up a bus for listening to child elements */
bus = gst_bus_new ();
bin->child_bus = bus;
GST_DEBUG_OBJECT (bin, "using bus %" GST_PTR_FORMAT " to listen to children",
bus);
gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bin_bus_handler, bin);
}
static void
gst_bin_dispose (GObject * object)
{
GstBin *bin = GST_BIN (object);
GstBus **child_bus_p = &bin->child_bus;
GstClock **provided_clock_p = &bin->provided_clock;
GstElement **clock_provider_p = &bin->clock_provider;
GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
gst_object_replace ((GstObject **) child_bus_p, NULL);
gst_object_replace ((GstObject **) provided_clock_p, NULL);
gst_object_replace ((GstObject **) clock_provider_p, NULL);
while (bin->children) {
gst_bin_remove (bin, GST_ELEMENT_CAST (bin->children->data));
}
if (G_UNLIKELY (bin->children != NULL)) {
g_critical ("could not remove elements from bin %s",
GST_STR_NULL (GST_OBJECT_NAME (object)));
}
G_OBJECT_CLASS (parent_class)->dispose (object);
}
/**
* gst_bin_new:
* @name: the name of the new bin
*
* Creates a new bin with the given name.
*
* Returns: a new #GstBin
*/
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_OBJECT_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_OBJECT_UNLOCK (bin);
}
#endif
/* set the clock on all elements in this bin
*
* MT safe
*/
static gboolean
gst_bin_set_clock_func (GstElement * element, GstClock * clock)
{
GList *children;
GstBin *bin;
gboolean res = TRUE;
bin = GST_BIN (element);
GST_OBJECT_LOCK (bin);
if (element->clock != clock) {
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
res &= gst_element_set_clock (child, clock);
}
}
GST_OBJECT_UNLOCK (bin);
return res;
}
/* get the clock for this bin by asking all of the children in this bin
*
* The ref of the returned clock in increased so unref after usage.
*
* We loop the elements in state order and pick the last clock we can
* get. This makes sure we get a clock from the source.
*
* MT safe
*/
static GstClock *
gst_bin_provide_clock_func (GstElement * element)
{
GstClock *result = NULL;
GstElement *provider = NULL;
GstBin *bin;
GstIterator *it;
gpointer val;
GstClock **provided_clock_p;
GstElement **clock_provider_p;
bin = GST_BIN (element);
GST_OBJECT_LOCK (bin);
if (!bin->clock_dirty)
goto not_dirty;
GST_DEBUG_OBJECT (bin, "finding new clock");
it = gst_bin_sort_iterator_new (bin);
while (it->next (it, &val) == GST_ITERATOR_OK) {
GstElement *child = GST_ELEMENT_CAST (val);
GstClock *clock;
clock = gst_element_provide_clock (child);
if (clock) {
GST_DEBUG_OBJECT (bin, "found candidate clock %p by element %s",
clock, GST_ELEMENT_NAME (child));
if (result) {
gst_object_unref (result);
gst_object_unref (provider);
}
result = clock;
provider = child;
} else {
gst_object_unref (child);
}
}
provided_clock_p = &bin->provided_clock;
clock_provider_p = &bin->clock_provider;
gst_object_replace ((GstObject **) provided_clock_p, (GstObject *) result);
gst_object_replace ((GstObject **) clock_provider_p, (GstObject *) provider);
bin->clock_dirty = FALSE;
GST_DEBUG_OBJECT (bin,
"provided new clock %" GST_PTR_FORMAT " by provider %" GST_PTR_FORMAT,
result, provider);
/* Provider is not being returned to caller, just the result */
if (provider)
gst_object_unref (provider);
GST_OBJECT_UNLOCK (bin);
gst_iterator_free (it);
return result;
not_dirty:
{
if ((result = bin->provided_clock))
gst_object_ref (result);
GST_DEBUG_OBJECT (bin, "returning old clock %p", result);
GST_OBJECT_UNLOCK (bin);
return result;
}
}
/*
* functions for manipulating cached messages
*/
typedef struct
{
GstObject *src;
GstMessageType types;
} MessageFind;
/* check if a message is of given src and type */
static gint
message_check (GstMessage * message, MessageFind * target)
{
gboolean eq = TRUE;
if (target->src)
eq &= GST_MESSAGE_SRC (message) == target->src;
if (target->types)
eq &= (GST_MESSAGE_TYPE (message) & target->types) != 0;
return (eq ? 0 : 1);
}
/* with LOCK, returns TRUE if message had a valid SRC, takes ref on
* the message.
*
* A message that is cached and has the same SRC and type is replaced
* by the given message.
*/
static gboolean
bin_replace_message (GstBin * bin, GstMessage * message, GstMessageType types)
{
GList *previous;
GstObject *src;
gboolean res = TRUE;
const gchar *name;
name = GST_MESSAGE_TYPE_NAME (message);
if ((src = GST_MESSAGE_SRC (message))) {
MessageFind find;
find.src = src;
find.types = types;
/* first find the previous message posted by this element */
previous = g_list_find_custom (bin->messages, &find,
(GCompareFunc) message_check);
if (previous) {
/* if we found a previous message, replace it */
gst_message_unref (previous->data);
previous->data = message;
GST_DEBUG_OBJECT (bin, "replace old message %s from %s",
name, GST_ELEMENT_NAME (src));
} else {
/* keep new message */
bin->messages = g_list_prepend (bin->messages, message);
GST_DEBUG_OBJECT (bin, "got new message %p, %s from %s",
message, name, GST_ELEMENT_NAME (src));
}
} else {
GST_DEBUG_OBJECT (bin, "got message %s from (NULL), not processing", name);
res = FALSE;
gst_message_unref (message);
}
return res;
}
/* with LOCK. Remove all messages of given types */
static void
bin_remove_messages (GstBin * bin, GstObject * src, GstMessageType types)
{
MessageFind find;
GList *walk, *next;
find.src = src;
find.types = types;
for (walk = bin->messages; walk; walk = next) {
GstMessage *message = (GstMessage *) walk->data;
next = g_list_next (walk);
if (message_check (message, &find) == 0) {
GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
"deleting message %p of types 0x%08x", message, types);
bin->messages = g_list_delete_link (bin->messages, walk);
gst_message_unref (message);
} else {
GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
"not deleting message %p of type 0x%08x", message,
GST_MESSAGE_TYPE (message));
}
}
}
/* Check if the bin is EOS. We do this by scanning all sinks and
* checking if they posted an EOS message.
*
* call with bin LOCK */
static gboolean
is_eos (GstBin * bin)
{
gboolean result;
GList *walk;
result = TRUE;
for (walk = bin->children; walk; walk = g_list_next (walk)) {
GstElement *element;
element = GST_ELEMENT_CAST (walk->data);
if (bin_element_is_sink (element, bin) == 0) {
MessageFind find;
/* check if element posted EOS */
find.src = GST_OBJECT_CAST (element);
find.types = GST_MESSAGE_EOS;
if (g_list_find_custom (bin->messages, &find,
(GCompareFunc) message_check)) {
GST_DEBUG ("element posted EOS");
} else {
GST_DEBUG ("element did not post EOS yet");
result = FALSE;
break;
}
}
}
return result;
}
static void
unlink_pads (GstPad * pad)
{
GstPad *peer;
if ((peer = gst_pad_get_peer (pad))) {
if (gst_pad_get_direction (pad) == GST_PAD_SRC)
gst_pad_unlink (pad, peer);
else
gst_pad_unlink (peer, pad);
gst_object_unref (peer);
}
gst_object_unref (pad);
}
/* vmethod that adds an element to a bin
*
* MT safe
*/
static gboolean
gst_bin_add_func (GstBin * bin, GstElement * element)
{
gchar *elem_name;
GstIterator *it;
gboolean is_sink;
GstMessage *clock_message = NULL;
/* 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. */
GST_OBJECT_LOCK (element);
elem_name = g_strdup (GST_ELEMENT_NAME (element));
is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
GST_OBJECT_UNLOCK (element);
GST_OBJECT_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 this check and before setting
* the object parent. The window is very small though... */
if (G_UNLIKELY (!gst_object_check_uniqueness (bin->children, elem_name)))
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;
/* if we add a sink we become a sink */
if (is_sink) {
GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was sink",
elem_name);
GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_IS_SINK);
}
if (gst_element_provides_clock (element)) {
GST_DEBUG_OBJECT (bin, "element \"%s\" can provide a clock", elem_name);
bin->clock_dirty = TRUE;
clock_message =
gst_message_new_clock_provide (GST_OBJECT_CAST (bin), NULL, TRUE);
}
bin->children = g_list_prepend (bin->children, element);
bin->numchildren++;
bin->children_cookie++;
/* distribute the bus */
gst_element_set_bus (element, bin->child_bus);
/* propagate the current base_time and clock */
gst_element_set_base_time (element, GST_ELEMENT (bin)->base_time);
/* it's possible that the element did not accept the clock but
* that is not important right now. When the pipeline goes to PLAYING,
* a new clock will be selected */
gst_element_set_clock (element, GST_ELEMENT_CLOCK (bin));
GST_DEBUG_OBJECT (bin, "marking state dirty");
bin->state_dirty = TRUE;
GST_OBJECT_UNLOCK (bin);
if (clock_message) {
gst_element_post_message (GST_ELEMENT_CAST (bin), clock_message);
}
/* unlink all linked pads */
it = gst_element_iterate_pads (element);
gst_iterator_foreach (it, (GFunc) unlink_pads, element);
gst_iterator_free (it);
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_OBJECT_LOCK (bin);
g_warning ("Cannot add bin %s to itself", GST_ELEMENT_NAME (bin));
GST_OBJECT_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_OBJECT_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
had_parent:
{
g_warning ("Element %s already has parent", elem_name);
GST_OBJECT_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
}
/**
* gst_bin_add:
* @bin: a #GstBin
* @element: the #GstElement to add
*
* 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.
*
* If the element's pads are linked to other pads, the pads will be unlinked
* before the element is added to the bin.
*
* MT safe.
*
* Returns: TRUE if the element could be added, FALSE if
* the bin does not want to accept the element.
*/
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_STR_NULL (GST_ELEMENT_NAME (element)),
GST_STR_NULL (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;
GstIterator *it;
gboolean is_sink;
GstMessage *clock_message = NULL, *async_message = NULL, *smessage = NULL;
GList *walk, *next;
gboolean other_async = FALSE, this_async = FALSE, cont = FALSE;
GST_OBJECT_LOCK (element);
/* Check if the element is already being removed and immediately
* return */
if (G_UNLIKELY (GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_UNPARENTING)))
goto already_removing;
GST_OBJECT_FLAG_SET (element, GST_ELEMENT_UNPARENTING);
/* grab element name so we can print it */
elem_name = g_strdup (GST_ELEMENT_NAME (element));
is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
GST_OBJECT_UNLOCK (element);
/* unlink all linked pads */
it = gst_element_iterate_pads (element);
gst_iterator_foreach (it, (GFunc) unlink_pads, element);
gst_iterator_free (it);
GST_OBJECT_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++;
/* check if we removed a sink */
if (is_sink) {
GList *other_sink;
/* check if we removed the last sink */
other_sink = g_list_find_custom (bin->children,
bin, (GCompareFunc) bin_element_is_sink);
if (!other_sink) {
/* yups, we're not a sink anymore */
GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_IS_SINK);
}
}
/* if the clock provider for this element is removed, we lost
* the clock as well, we need to inform the parent of this
* so that it can select a new clock */
if (bin->clock_provider == element) {
GST_DEBUG_OBJECT (bin, "element \"%s\" provided the clock", elem_name);
bin->clock_dirty = TRUE;
clock_message =
gst_message_new_clock_lost (GST_OBJECT_CAST (bin), bin->provided_clock);
}
/* remove messages for the element, if there was a pending ASYNC_START
* message we must see if removing the element caused the bin to lose its
* async state. */
for (walk = bin->messages; walk; walk = next) {
GstMessage *message = (GstMessage *) walk->data;
GstElement *src = GST_ELEMENT_CAST (GST_MESSAGE_SRC (message));
next = g_list_next (walk);
if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ASYNC_START) {
if (src == element)
this_async = TRUE;
else
other_async = TRUE;
GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
"looking at message %p", message);
}
if (src == element) {
/* delete all message types */
GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
"deleting message %p of element \"%s\"", message, elem_name);
bin->messages = g_list_delete_link (bin->messages, walk);
gst_message_unref (message);
}
}
/* all other elements were not async and we removed the async one,
* post a ASYNC_DONE message because we are not async anymore now. */
if (!other_async && this_async) {
GST_DEBUG_OBJECT (bin, "we removed the last async element");
cont = GST_OBJECT_PARENT (bin) == NULL;
if (!cont) {
bin_handle_async_done (bin, &smessage);
async_message = gst_message_new_async_done (GST_OBJECT_CAST (bin));
}
}
GST_DEBUG_OBJECT (bin, "marking state dirty");
bin->state_dirty = TRUE;
GST_OBJECT_UNLOCK (bin);
if (clock_message)
gst_element_post_message (GST_ELEMENT_CAST (bin), clock_message);
if (smessage)
gst_element_post_message (GST_ELEMENT_CAST (bin), smessage);
if (async_message)
gst_element_post_message (GST_ELEMENT_CAST (bin), async_message);
if (cont)
bin_push_state_continue (bin);
GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
elem_name);
g_free (elem_name);
gst_element_set_bus (element, NULL);
/* Clear the clock we provided to the element */
gst_element_set_clock (element, NULL);
/* we ref here because after the _unparent() the element can be disposed
* and we still need it to reset the UNPARENTING flag and fire a signal. */
gst_object_ref (element);
gst_object_unparent (GST_OBJECT_CAST (element));
GST_OBJECT_LOCK (element);
GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_UNPARENTING);
GST_OBJECT_UNLOCK (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 (element);
return TRUE;
/* ERROR handling */
not_in_bin:
{
g_warning ("Element %s is not in bin %s", elem_name,
GST_ELEMENT_NAME (bin));
GST_OBJECT_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
already_removing:
{
GST_OBJECT_UNLOCK (element);
return FALSE;
}
}
/**
* gst_bin_remove:
* @bin: a #GstBin
* @element: the #GstElement to remove
*
* Removes the element from the 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.
*
* If the element's pads are linked to other pads, the pads will be unlinked
* before the element is removed from the bin.
*
* MT safe.
*
* Returns: TRUE if the element could be removed, FALSE if
* the bin does not want to remove the element.
*/
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 (child);
return GST_ITERATOR_ITEM_PASS;
}
/**
* gst_bin_iterate_elements:
* @bin: a #GstBin
*
* Gets an iterator for the elements in this bin.
*
* Each element yielded by the iterator will have its refcount increased, so
* unref after use.
*
* MT safe. Caller owns returned value.
*
* Returns: a #GstIterator of #GstElement, or NULL
*/
GstIterator *
gst_bin_iterate_elements (GstBin * bin)
{
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
GST_OBJECT_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 (bin);
result = gst_iterator_new_list (GST_TYPE_ELEMENT,
GST_OBJECT_GET_LOCK (bin),
&bin->children_cookie,
&bin->children,
bin,
(GstIteratorItemFunction) iterate_child,
(GstIteratorDisposeFunction) gst_object_unref);
GST_OBJECT_UNLOCK (bin);
return result;
}
static GstIteratorItem
iterate_child_recurse (GstIterator * it, GstElement * child)
{
gst_object_ref (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: a #GstBin
*
* Gets an iterator for the elements in this bin.
* This iterator recurses into GstBin children.
*
* Each element yielded by the iterator will have its refcount increased, so
* unref after use.
*
* MT safe. Caller owns returned value.
*
* Returns: a #GstIterator of #GstElement, or NULL
*/
GstIterator *
gst_bin_iterate_recurse (GstBin * bin)
{
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
GST_OBJECT_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 (bin);
result = gst_iterator_new_list (GST_TYPE_ELEMENT,
GST_OBJECT_GET_LOCK (bin),
&bin->children_cookie,
&bin->children,
bin,
(GstIteratorItemFunction) iterate_child_recurse,
(GstIteratorDisposeFunction) gst_object_unref);
GST_OBJECT_UNLOCK (bin);
return result;
}
/* returns 0 when TRUE because this is a GCompareFunc */
/* MT safe */
static gint
bin_element_is_sink (GstElement * child, GstBin * bin)
{
gboolean is_sink;
/* we lock the child here for the remainder of the function to
* get its name and flag safely. */
GST_OBJECT_LOCK (child);
is_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_IS_SINK);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
"child %s %s sink", GST_OBJECT_NAME (child), is_sink ? "is" : "is not");
GST_OBJECT_UNLOCK (child);
return is_sink ? 0 : 1;
}
static gint
sink_iterator_filter (GstElement * child, GstBin * bin)
{
if (bin_element_is_sink (child, bin) == 0) {
/* returns 0 because this is a GCompareFunc */
return 0;
} else {
/* child carries a ref from gst_bin_iterate_elements -- drop if not passing
through */
gst_object_unref (child);
return 1;
}
}
/**
* gst_bin_iterate_sinks:
* @bin: a #GstBin
*
* Gets an iterator for all elements in the bin that have the
* #GST_ELEMENT_IS_SINK flag set.
*
* Each element yielded by the iterator will have its refcount increased, so
* unref after use.
*
* MT safe. Caller owns returned value.
*
* Returns: a #GstIterator of #GstElement, or NULL
*/
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) sink_iterator_filter, bin);
return result;
}
/* returns 0 when TRUE because this is a GCompareFunc */
/* MT safe */
static gint
bin_element_is_src (GstElement * child, GstBin * bin)
{
gboolean is_src = FALSE;
/* we lock the child here for the remainder of the function to
* get its name and flag safely. */
GST_OBJECT_LOCK (child);
if (!GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_IS_SINK) &&
!child->numsinkpads) {
is_src = TRUE;
}
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
"child %s %s src", GST_OBJECT_NAME (child), is_src ? "is" : "is not");
GST_OBJECT_UNLOCK (child);
return is_src ? 0 : 1;
}
static gint
src_iterator_filter (GstElement * child, GstBin * bin)
{
if (bin_element_is_src (child, bin) == 0) {
/* returns 0 because this is a GCompareFunc */
return 0;
} else {
/* child carries a ref from gst_bin_iterate_elements -- drop if not passing
through */
gst_object_unref (child);
return 1;
}
}
/**
* gst_bin_iterate_sources:
* @bin: a #GstBin
*
* Gets an iterator for all elements in the bin that have no sinkpads and have
* the #GST_ELEMENT_IS_SINK flag unset.
*
* Each element yielded by the iterator will have its refcount increased, so
* unref after use.
*
* MT safe. Caller owns returned value.
*
* Returns: a #GstIterator of #GstElement, or NULL
*/
GstIterator *
gst_bin_iterate_sources (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) src_iterator_filter, bin);
return result;
}
static void
gst_bin_recalc_state (GstBin * bin, gboolean force)
{
GstStateChangeReturn ret;
GList *children;
guint32 children_cookie;
guint32 state_cookie;
gboolean have_no_preroll;
gboolean have_async;
ret = GST_STATE_CHANGE_SUCCESS;
/* lock bin, no element can be added or removed while we have this lock */
GST_OBJECT_LOCK (bin);
/* forced recalc, make state dirty again */
if (force)
bin->state_dirty = TRUE;
/* no point in scanning if nothing changed and it's no forced recalc */
if (!bin->state_dirty)
goto not_dirty;
/* no point in having two scans run concurrently */
if (bin->polling)
goto was_polling;
bin->polling = TRUE;
state_cookie = GST_ELEMENT_CAST (bin)->state_cookie;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "recalc state");
restart:
/* when we leave this function, the state must not be dirty, whenever
* we are scanning and the state becomes dirty again, we restart. */
bin->state_dirty = FALSE;
have_no_preroll = FALSE;
have_async = FALSE;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "checking element states");
/* scan all element states with a zero timeout so we don't block on
* anything */
children = bin->children;
children_cookie = bin->children_cookie;
while (children) {
GstElement *child = GST_ELEMENT_CAST (children->data);
gst_object_ref (child);
/* now we release the lock to enter a non blocking wait. We
* release the lock anyway since we can. */
GST_OBJECT_UNLOCK (bin);
ret = gst_element_get_state (child, NULL, NULL, 0);
gst_object_unref (child);
/* now grab the lock to iterate to the next child */
GST_OBJECT_LOCK (bin);
if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
/* child added/removed during state change, restart. We need
* to restart with the quick check as a no-preroll element could
* have been added here and we don't want to block on sinks then.*/
GST_DEBUG_OBJECT (bin, "children added or removed, restarting recalc");
goto restart;
}
if (state_cookie != GST_ELEMENT_CAST (bin)->state_cookie) {
GST_DEBUG_OBJECT (bin, "concurrent state change");
goto concurrent_state;
}
if (bin->state_dirty) {
GST_DEBUG_OBJECT (bin, "state dirty again, restarting recalc");
goto restart;
}
switch (ret) {
case GST_STATE_CHANGE_FAILURE:
/* report FAILURE immediatly */
goto done;
case GST_STATE_CHANGE_NO_PREROLL:
/* we have to continue scanning as there might be
* ERRORS too */
have_no_preroll = TRUE;
break;
case GST_STATE_CHANGE_ASYNC:
/* we have to continue scanning as there might be
* ERRORS too */
have_async = TRUE;
break;
default:
break;
}
children = g_list_next (children);
}
/* if we get here, we have no FAILURES */
/* if we have NO_PREROLL, return that */
if (have_no_preroll) {
ret = GST_STATE_CHANGE_NO_PREROLL;
}
/* else return ASYNC if async elements where found. */
else if (have_async) {
ret = GST_STATE_CHANGE_ASYNC;
}
done:
bin->polling = FALSE;
GST_STATE_RETURN (bin) = ret;
GST_OBJECT_UNLOCK (bin);
/* now we can take the state lock, it is possible that new elements
* are added now and we still report the old state. No problem though as
* the return is still consistent, the effect is as if the element was
* added after this function completed. */
switch (ret) {
case GST_STATE_CHANGE_SUCCESS:
case GST_STATE_CHANGE_NO_PREROLL:
ret = gst_element_continue_state (GST_ELEMENT_CAST (bin), ret);
break;
case GST_STATE_CHANGE_ASYNC:
gst_element_lost_state (GST_ELEMENT_CAST (bin));
break;
case GST_STATE_CHANGE_FAILURE:
gst_element_abort_state (GST_ELEMENT_CAST (bin));
break;
default:
goto unknown_state;
}
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "bin RETURN is now %s",
gst_element_state_change_return_get_name (ret));
return;
not_dirty:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "not dirty");
GST_OBJECT_UNLOCK (bin);
return;
}
was_polling:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "was polling");
GST_OBJECT_UNLOCK (bin);
return;
}
concurrent_state:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "concurrent_state");
bin->polling = FALSE;
GST_OBJECT_UNLOCK (bin);
return;
}
unknown_state:
{
/* somebody added a GST_STATE_ and forgot to do stuff here ! */
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
"unknown return value %d from a state change function", ret);
g_critical ("unknown return value %d from a state change function", ret);
GST_STATE_RETURN (bin) = GST_STATE_CHANGE_FAILURE;
GST_STATE_UNLOCK (bin);
return;
}
}
/*
* MT safe
*/
static GstStateChangeReturn
gst_bin_get_state_func (GstElement * element, GstState * state,
GstState * pending, GstClockTime timeout)
{
GstBin *bin = GST_BIN (element);
GstStateChangeReturn ret;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "getting state");
/* do a non forced recalculation of the state */
gst_bin_recalc_state (bin, FALSE);
ret = parent_class->get_state (element, state, pending, timeout);
return ret;
}
/***********************************************
* Topologically sorted iterator
* see http://en.wikipedia.org/wiki/Topological_sorting
*
* For each element in the graph, an entry is kept in a HashTable
* with its number of srcpad connections (degree).
* We then change state of all elements without dependencies
* (degree 0) and decrement the degree of all elements connected
* on the sinkpads. When an element reaches degree 0, its state is
* changed next.
* When all elements are handled the algorithm stops.
*/
typedef struct _GstBinSortIterator
{
GstIterator it;
GQueue *queue; /* elements queued for state change */
GstBin *bin; /* bin we iterate */
gint mode; /* adding or removing dependency */
GstElement *best; /* next element with least dependencies */
gint best_deg; /* best degree */
GHashTable *hash; /* hashtable with element dependencies */
} GstBinSortIterator;
/* we add and subtract 1 to make sure we don't confuse NULL and 0 */
#define HASH_SET_DEGREE(bit, elem, deg) \
g_hash_table_replace (bit->hash, elem, GINT_TO_POINTER(deg+1))
#define HASH_GET_DEGREE(bit, elem) \
(GPOINTER_TO_INT(g_hash_table_lookup (bit->hash, elem))-1)
/* add element to queue of next elements in the iterator.
* We push at the tail to give higher priority elements a
* chance first */
static void
add_to_queue (GstBinSortIterator * bit, GstElement * element)
{
GST_DEBUG_OBJECT (bit->bin, "%s add to queue", GST_ELEMENT_NAME (element));
gst_object_ref (element);
g_queue_push_tail (bit->queue, element);
HASH_SET_DEGREE (bit, element, -1);
}
/* clear the queue, unref all objects as we took a ref when
* we added them to the queue */
static void
clear_queue (GQueue * queue)
{
gpointer p;
while ((p = g_queue_pop_head (queue)))
gst_object_unref (p);
}
/* set all degrees to 0. Elements marked as a sink are
* added to the queue immediatly. */
static void
reset_degree (GstElement * element, GstBinSortIterator * bit)
{
gboolean is_sink;
/* sinks are added right away */
GST_OBJECT_LOCK (element);
is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
GST_OBJECT_UNLOCK (element);
if (is_sink) {
add_to_queue (bit, element);
} else {
/* others are marked with 0 and handled when sinks are done */
HASH_SET_DEGREE (bit, element, 0);
}
}
/* adjust the degree of all elements connected to the given
* element. If an degree of an element drops to 0, it is
* added to the queue of elements to schedule next.
*
* We have to make sure not to cross the bin boundary this element
* belongs to.
*/
static void
update_degree (GstElement * element, GstBinSortIterator * bit)
{
gboolean linked = FALSE;
GST_OBJECT_LOCK (element);
/* don't touch degree if element has no sourcepads */
if (element->numsinkpads != 0) {
/* loop over all sinkpads, decrement degree for all connected
* elements in this bin */
GList *pads;
for (pads = element->sinkpads; pads; pads = g_list_next (pads)) {
GstPad *peer;
if ((peer = gst_pad_get_peer (GST_PAD_CAST (pads->data)))) {
GstElement *peer_element;
if ((peer_element = gst_pad_get_parent_element (peer))) {
GST_OBJECT_LOCK (peer_element);
/* check that we don't go outside of this bin */
if (GST_OBJECT_CAST (peer_element)->parent ==
GST_OBJECT_CAST (bit->bin)) {
gint old_deg, new_deg;
old_deg = HASH_GET_DEGREE (bit, peer_element);
new_deg = old_deg + bit->mode;
GST_DEBUG_OBJECT (bit->bin,
"change element %s, degree %d->%d, linked to %s",
GST_ELEMENT_NAME (peer_element), old_deg, new_deg,
GST_ELEMENT_NAME (element));
/* update degree */
if (new_deg == 0) {
/* degree hit 0, add to queue */
add_to_queue (bit, peer_element);
} else {
HASH_SET_DEGREE (bit, peer_element, new_deg);
}
linked = TRUE;
}
GST_OBJECT_UNLOCK (peer_element);
gst_object_unref (peer_element);
}
gst_object_unref (peer);
}
}
}
if (!linked) {
GST_DEBUG_OBJECT (bit->bin, "element %s not linked on any sinkpads",
GST_ELEMENT_NAME (element));
}
GST_OBJECT_UNLOCK (element);
}
/* find the next best element not handled yet. This is the one
* with the lowest non-negative degree */
static void
find_element (GstElement * element, GstBinSortIterator * bit)
{
gint degree;
/* element is already handled */
if ((degree = HASH_GET_DEGREE (bit, element)) < 0)
return;
/* first element or element with smaller degree */
if (bit->best == NULL || bit->best_deg > degree) {
bit->best = element;
bit->best_deg = degree;
}
}
/* get next element in iterator. the returned element has the
* refcount increased */
static GstIteratorResult
gst_bin_sort_iterator_next (GstBinSortIterator * bit, gpointer * result)
{
GstBin *bin = bit->bin;
/* empty queue, we have to find a next best element */
if (g_queue_is_empty (bit->queue)) {
GstElement *best;
bit->best = NULL;
bit->best_deg = G_MAXINT;
g_list_foreach (bin->children, (GFunc) find_element, bit);
if ((best = bit->best)) {
if (bit->best_deg != 0) {
/* we don't fail on this one yet */
g_warning ("loop detected in the graph !!");
}
/* best unhandled element, schedule as next element */
GST_DEBUG_OBJECT (bin, "queue empty, next best: %s",
GST_ELEMENT_NAME (best));
gst_object_ref (best);
HASH_SET_DEGREE (bit, best, -1);
*result = best;
} else {
GST_DEBUG_OBJECT (bin, "queue empty, elements exhausted");
/* no more unhandled elements, we are done */
return GST_ITERATOR_DONE;
}
} else {
/* everything added to the queue got reffed */
*result = g_queue_pop_head (bit->queue);
}
GST_DEBUG_OBJECT (bin, "queue head gives %s", GST_ELEMENT_NAME (*result));
/* update degrees of linked elements */
update_degree (GST_ELEMENT_CAST (*result), bit);
return GST_ITERATOR_OK;
}
/* clear queues, recalculate the degrees and restart. */
static void
gst_bin_sort_iterator_resync (GstBinSortIterator * bit)
{
GstBin *bin = bit->bin;
GST_DEBUG_OBJECT (bin, "resync");
clear_queue (bit->queue);
/* reset degrees */
g_list_foreach (bin->children, (GFunc) reset_degree, bit);
/* calc degrees, incrementing */
bit->mode = 1;
g_list_foreach (bin->children, (GFunc) update_degree, bit);
/* for the rest of the function we decrement the degrees */
bit->mode = -1;
}
/* clear queues, unref bin and free iterator. */
static void
gst_bin_sort_iterator_free (GstBinSortIterator * bit)
{
GstBin *bin = bit->bin;
GST_DEBUG_OBJECT (bin, "free");
clear_queue (bit->queue);
g_queue_free (bit->queue);
g_hash_table_destroy (bit->hash);
gst_object_unref (bin);
g_free (bit);
}
/* should be called with the bin LOCK held */
static GstIterator *
gst_bin_sort_iterator_new (GstBin * bin)
{
GstBinSortIterator *result;
/* we don't need an ItemFunction because we ref the items in the _next
* method already */
result = (GstBinSortIterator *)
gst_iterator_new (sizeof (GstBinSortIterator),
GST_TYPE_ELEMENT,
GST_OBJECT_GET_LOCK (bin),
&bin->children_cookie,
(GstIteratorNextFunction) gst_bin_sort_iterator_next,
(GstIteratorItemFunction) NULL,
(GstIteratorResyncFunction) gst_bin_sort_iterator_resync,
(GstIteratorFreeFunction) gst_bin_sort_iterator_free);
result->queue = g_queue_new ();
result->hash = g_hash_table_new (NULL, NULL);
gst_object_ref (bin);
result->bin = bin;
gst_bin_sort_iterator_resync (result);
return (GstIterator *) result;
}
/**
* gst_bin_iterate_sorted:
* @bin: a #GstBin
*
* Gets an iterator for the elements in this bin in topologically
* sorted order. This means that the elements are returned from
* the most downstream elements (sinks) to the sources.
*
* This function is used internally to perform the state changes
* of the bin elements.
*
* Each element yielded by the iterator will have its refcount increased, so
* unref after use.
*
* MT safe. Caller owns returned value.
*
* Returns: a #GstIterator of #GstElement, or NULL
*/
GstIterator *
gst_bin_iterate_sorted (GstBin * bin)
{
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
GST_OBJECT_LOCK (bin);
result = gst_bin_sort_iterator_new (bin);
GST_OBJECT_UNLOCK (bin);
return result;
}
static GstStateChangeReturn
gst_bin_element_set_state (GstBin * bin, GstElement * element,
GstClockTime base_time, GstState current, GstState next)
{
GstStateChangeReturn ret;
gboolean locked;
GList *found;
MessageFind find;
/* peel off the locked flag */
GST_OBJECT_LOCK (element);
locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
GST_OBJECT_UNLOCK (element);
/* skip locked elements */
if (G_UNLIKELY (locked))
goto locked;
/* the element was busy with an upwards async state change, we must wait for
* an ASYNC_DONE message before we attemp to change the state. */
find.src = GST_OBJECT_CAST (element);
find.types = GST_MESSAGE_ASYNC_START;
GST_OBJECT_LOCK (bin);
if ((found = g_list_find_custom (bin->messages, &find,
(GCompareFunc) message_check))) {
#ifndef GST_DISABLE_GST_DEBUG
GstMessage *message = GST_MESSAGE_CAST (found->data);
#endif
GST_DEBUG_OBJECT (element, "element message %p, %s async busy",
message, GST_ELEMENT_NAME (GST_MESSAGE_SRC (message)));
/* only wait for upward state changes */
if (next > current) {
/* We found an async element check if we can force its state to change or
* if we have to wait for it to preroll. */
if (G_UNLIKELY (!enable_latency)) {
g_warning ("Future versions of GStreamer will wait for element \"%s\"\n"
"\tto preroll in order to perform correct latency calculations.\n"
"\tPlease verify that the application continues to work correctly by\n"
"\tsetting the environment variable GST_COMPAT to a value containing\n"
"\tthe string 'live-preroll'.", GST_ELEMENT_NAME (element));
goto no_latency;
}
goto was_busy;
}
}
no_latency:
GST_OBJECT_UNLOCK (bin);
GST_DEBUG_OBJECT (bin,
"setting element %s to %s, base_time %" GST_TIME_FORMAT,
GST_ELEMENT_NAME (element), gst_element_state_get_name (next),
GST_TIME_ARGS (base_time));
/* set base_time on child */
gst_element_set_base_time (element, base_time);
/* change state */
ret = gst_element_set_state (element, next);
return ret;
locked:
{
GST_DEBUG_OBJECT (element,
"element is locked, pretending state change succeeded");
return GST_STATE_CHANGE_SUCCESS;
}
was_busy:
{
GST_DEBUG_OBJECT (element, "element is was busy delaying state change");
GST_OBJECT_UNLOCK (bin);
return GST_STATE_CHANGE_ASYNC;
}
}
/* gst_iterator_fold functions for pads_activate
* Note how we don't stop the iterator when we fail an activation. This is
* probably a FIXME since when one pad activation fails, we don't want to
* continue our state change. */
static gboolean
activate_pads (GstPad * pad, GValue * ret, gboolean * active)
{
if (!gst_pad_set_active (pad, *active))
g_value_set_boolean (ret, FALSE);
else if (!*active)
gst_pad_set_caps (pad, NULL);
/* unref the object that was reffed for us by _fold */
gst_object_unref (pad);
return TRUE;
}
/* returns false on error or early cutout (will never happen because the fold
* function always returns TRUE, see FIXME above) of the fold, true if all
* pads in @iter were (de)activated successfully. */
static gboolean
iterator_activate_fold_with_resync (GstIterator * iter, 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, (GstIteratorFoldFunction) activate_pads,
&ret, user_data);
switch (ires) {
case GST_ITERATOR_RESYNC:
/* need to reset the result again */
g_value_set_boolean (&ret, TRUE);
gst_iterator_resync (iter);
break;
case GST_ITERATOR_DONE:
/* all pads iterated, return collected value */
goto done;
default:
/* iterator returned _ERROR or premature end with _OK,
* mark an error and exit */
g_value_set_boolean (&ret, FALSE);
goto done;
}
}
done:
/* return collected value */
return g_value_get_boolean (&ret);
}
/* is called with STATE_LOCK
*/
static gboolean
gst_bin_src_pads_activate (GstBin * bin, gboolean active)
{
GstIterator *iter;
gboolean fold_ok;
GST_DEBUG_OBJECT (bin, "src_pads_activate with active %d", active);
iter = gst_element_iterate_src_pads ((GstElement *) bin);
fold_ok = iterator_activate_fold_with_resync (iter, &active);
gst_iterator_free (iter);
if (G_UNLIKELY (!fold_ok))
goto failed;
GST_DEBUG_OBJECT (bin, "pads_activate successful");
return TRUE;
/* ERRORS */
failed:
{
GST_DEBUG_OBJECT (bin, "source pads_activate failed");
return FALSE;
}
}
static GstStateChangeReturn
gst_bin_change_state_func (GstElement * element, GstStateChange transition)
{
GstBin *bin;
GstStateChangeReturn ret;
GstState current, next;
gboolean have_async;
gboolean have_no_preroll;
GstClockTime base_time;
GstIterator *it;
gboolean done;
/* we don't need to take the STATE_LOCK, it is already taken */
current = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
next = (GstState) GST_STATE_TRANSITION_NEXT (transition);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"changing state of children from %s to %s",
gst_element_state_get_name (current), gst_element_state_get_name (next));
bin = GST_BIN_CAST (element);
switch (next) {
case GST_STATE_PAUSED:
/* Clear EOS list on next PAUSED */
GST_OBJECT_LOCK (bin);
GST_DEBUG_OBJECT (element, "clearing EOS elements");
bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
GST_OBJECT_UNLOCK (bin);
if (current == GST_STATE_READY)
if (!(gst_bin_src_pads_activate (bin, TRUE)))
goto activate_failure;
break;
case GST_STATE_READY:
/* Clear message list on next READY */
GST_OBJECT_LOCK (bin);
GST_DEBUG_OBJECT (element, "clearing all cached messages");
bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
GST_OBJECT_UNLOCK (bin);
if (current == GST_STATE_PAUSED)
if (!(gst_bin_src_pads_activate (bin, FALSE)))
goto activate_failure;
break;
case GST_STATE_NULL:
if (current == GST_STATE_READY)
if (!(gst_bin_src_pads_activate (bin, FALSE)))
goto activate_failure;
break;
default:
break;
}
/* iterate in state change order */
it = gst_bin_iterate_sorted (bin);
restart:
/* take base_time */
base_time = gst_element_get_base_time (element);
have_async = FALSE;
have_no_preroll = FALSE;
done = FALSE;
while (!done) {
gpointer data;
switch (gst_iterator_next (it, &data)) {
case GST_ITERATOR_OK:
{
GstElement *child;
child = GST_ELEMENT_CAST (data);
/* set state and base_time now */
ret = gst_bin_element_set_state (bin, child, base_time, current, next);
switch (ret) {
case GST_STATE_CHANGE_SUCCESS:
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"child '%s' changed state to %d(%s) successfully",
GST_ELEMENT_NAME (child), next,
gst_element_state_get_name (next));
break;
case GST_STATE_CHANGE_ASYNC:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"child '%s' is changing state asynchronously to %s",
GST_ELEMENT_NAME (child), gst_element_state_get_name (next));
have_async = TRUE;
break;
}
case GST_STATE_CHANGE_FAILURE:
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"child '%s' failed to go to state %d(%s)",
GST_ELEMENT_NAME (child),
next, gst_element_state_get_name (next));
gst_object_unref (child);
goto done;
case GST_STATE_CHANGE_NO_PREROLL:
GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
"child '%s' changed state to %d(%s) successfully without preroll",
GST_ELEMENT_NAME (child), next,
gst_element_state_get_name (next));
have_no_preroll = TRUE;
break;
default:
g_assert_not_reached ();
break;
}
gst_object_unref (child);
break;
}
case GST_ITERATOR_RESYNC:
GST_CAT_DEBUG (GST_CAT_STATES, "iterator doing resync");
gst_iterator_resync (it);
goto restart;
default:
case GST_ITERATOR_DONE:
GST_CAT_DEBUG (GST_CAT_STATES, "iterator done");
done = TRUE;
break;
}
}
ret = parent_class->change_state (element, transition);
if (G_UNLIKELY (ret == GST_STATE_CHANGE_FAILURE))
goto done;
if (have_no_preroll) {
ret = GST_STATE_CHANGE_NO_PREROLL;
} else if (have_async) {
ret = GST_STATE_CHANGE_ASYNC;
}
done:
gst_iterator_free (it);
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"done changing bin's state from %s to %s, now in %s, ret %s",
gst_element_state_get_name (current),
gst_element_state_get_name (next),
gst_element_state_get_name (GST_STATE (element)),
gst_element_state_change_return_get_name (ret));
return ret;
/* ERRORS */
activate_failure:
{
GST_CAT_WARNING_OBJECT (GST_CAT_STATES, element,
"failure (de)activating src pads");
return GST_STATE_CHANGE_FAILURE;
}
}
/*
* This function is a utility event handler for seek events.
* It will send the event to all sinks or sources depending on the
* event-direction.
*
* 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;
if (GST_EVENT_IS_DOWNSTREAM (event)) {
iter = gst_bin_iterate_sources (bin);
GST_DEBUG_OBJECT (bin, "Sending %s event to src children",
GST_EVENT_TYPE_NAME (event));
} else {
iter = gst_bin_iterate_sinks (bin);
GST_DEBUG_OBJECT (bin, "Sending %s event to sink children",
GST_EVENT_TYPE_NAME (event));
}
while (!done) {
gpointer data;
switch (gst_iterator_next (iter, &data)) {
case GST_ITERATOR_OK:
{
GstElement *child;
gst_event_ref (event);
child = GST_ELEMENT_CAST (data);
res &= gst_element_send_event (child, event);
gst_object_unref (child);
break;
}
case GST_ITERATOR_RESYNC:
gst_iterator_resync (iter);
res = TRUE;
break;
case GST_ITERATOR_DONE:
done = TRUE;
break;
case GST_ITERATOR_ERROR:
g_assert_not_reached ();
break;
}
}
gst_iterator_free (iter);
gst_event_unref (event);
return res;
}
static void
gst_bin_continue_func (GstBin * bin, gpointer data)
{
GstState current, next, pending, target, old_state, old_next;
GstStateChangeReturn old_ret, ret;
GstStateChange transition;
gboolean busy, post;
GST_DEBUG_OBJECT (bin, "waiting for state lock");
GST_STATE_LOCK (bin);
GST_DEBUG_OBJECT (bin, "doing state continue");
GST_OBJECT_LOCK (bin);
old_ret = GST_STATE_RETURN (bin);
GST_STATE_RETURN (bin) = GST_STATE_CHANGE_SUCCESS;
busy = (old_ret == GST_STATE_CHANGE_ASYNC);
target = GST_STATE_TARGET (bin);
pending = GST_STATE_PENDING (bin);
/* check if there is something to commit */
if (pending == GST_STATE_VOID_PENDING)
goto nothing_pending;
old_state = GST_STATE (bin);
/* this is the state we should go to next */
old_next = GST_STATE_NEXT (bin);
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "busy %d, target %s",
busy, gst_element_state_get_name (target));
if (old_next == GST_STATE_PLAYING) {
post = FALSE;
} else {
post = TRUE;
}
/* we're going to PLAYING, always do the PAUSED->PLAYING state change */
if (target == GST_STATE_PLAYING) {
next = GST_STATE_PAUSED;
GST_STATE_PENDING (bin) = pending = target;
} else {
next = old_next;
}
/* update current state */
current = GST_STATE (bin) = 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 (bin) = next;
/* mark busy */
GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
GST_OBJECT_UNLOCK (bin);
if (post) {
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
"committing state from %s to %s, pending %s",
gst_element_state_get_name (old_state),
gst_element_state_get_name (old_next),
gst_element_state_get_name (pending));
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_state_changed (GST_OBJECT_CAST (bin),
old_state, old_next, pending));
}
if (busy) {
GST_DEBUG_OBJECT (bin, "posting ASYNC_DONE");
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_async_done (GST_OBJECT_CAST (bin)));
}
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
"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 (GST_ELEMENT_CAST (bin), transition);
done:
GST_STATE_UNLOCK (bin);
GST_DEBUG_OBJECT (bin, "state continue done");
gst_object_unref (bin);
return;
nothing_pending:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "nothing pending");
GST_OBJECT_UNLOCK (bin);
goto done;
}
complete:
{
GST_STATE_PENDING (bin) = GST_STATE_VOID_PENDING;
GST_STATE_NEXT (bin) = GST_STATE_VOID_PENDING;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "completed state change to %s",
gst_element_state_get_name (pending));
GST_OBJECT_UNLOCK (bin);
/* don't post silly messages with the same state. This can happen
* when an element state is changed to what it already was. For bins
* this can be the result of a lost state, which we check with the
* previous return value.
* We do signal the cond though as a _get_state() might be blocking
* on it. */
if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_state_changed (GST_OBJECT_CAST (bin),
old_state, old_next, GST_STATE_VOID_PENDING));
}
GST_DEBUG_OBJECT (bin, "posting ASYNC_DONE");
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_async_done (GST_OBJECT_CAST (bin)));
GST_STATE_BROADCAST (bin);
goto done;
}
}
static GstBusSyncReply
bin_bus_handler (GstBus * bus, GstMessage * message, GstBin * bin)
{
GstBinClass *bclass;
bclass = GST_BIN_GET_CLASS (bin);
if (bclass->handle_message)
bclass->handle_message (bin, message);
else
gst_message_unref (message);
return GST_BUS_DROP;
}
static void
bin_push_state_continue (GstBin * bin)
{
GstBinClass *klass;
/* mark the bin dirty */
GST_OBJECT_LOCK (bin);
klass = GST_BIN_GET_CLASS (bin);
GST_DEBUG_OBJECT (bin, "pushing continue on thread pool");
gst_object_ref (bin);
g_thread_pool_push (klass->pool, bin, NULL);
GST_OBJECT_UNLOCK (bin);
}
/* an element started an async state change, if we were not busy with a state
* change, we perform a lost state.
*/
static void
bin_handle_async_start (GstBin * bin, GstMessage ** message)
{
GstState old_state, new_state;
if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
goto had_error;
if (GST_STATE_PENDING (bin) != GST_STATE_VOID_PENDING)
goto was_busy;
old_state = GST_STATE (bin);
if (old_state > GST_STATE_PAUSED)
new_state = GST_STATE_PAUSED;
else
new_state = old_state;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
"lost state of %s, new %s", gst_element_state_get_name (old_state),
gst_element_state_get_name (new_state));
GST_STATE (bin) = new_state;
GST_STATE_NEXT (bin) = new_state;
GST_STATE_PENDING (bin) = new_state;
GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
*message = gst_message_new_state_changed (GST_OBJECT_CAST (bin),
new_state, new_state, new_state);
return;
had_error:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
return;
}
was_busy:
{
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
return;
}
}
static void
bin_handle_async_done (GstBin * bin, GstMessage ** message)
{
GstState pending;
GstStateChangeReturn old_ret;
GstState old_state, old_next;
GstState current, next;
old_ret = GST_STATE_RETURN (bin);
GST_STATE_RETURN (bin) = GST_STATE_CHANGE_SUCCESS;
pending = GST_STATE_PENDING (bin);
/* check if there is something to commit */
if (pending == GST_STATE_VOID_PENDING)
goto nothing_pending;
old_state = GST_STATE (bin);
/* this is the state we should go to next */
old_next = GST_STATE_NEXT (bin);
/* update current state */
current = GST_STATE (bin) = old_next;
/* see if we reached the final state */
if (pending == current)
goto complete;
next = GST_STATE_GET_NEXT (current, pending);
GST_STATE_NEXT (bin) = next;
/* mark busy */
GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
"committing state from %s to %s, pending %s",
gst_element_state_get_name (old_state),
gst_element_state_get_name (old_next),
gst_element_state_get_name (pending));
*message = gst_message_new_state_changed (GST_OBJECT_CAST (bin),
old_state, old_next, pending);
return;
nothing_pending:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "nothing pending");
return;
}
complete:
{
GST_STATE_PENDING (bin) = GST_STATE_VOID_PENDING;
GST_STATE_NEXT (bin) = GST_STATE_VOID_PENDING;
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "completed state change");
/* 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) {
*message = gst_message_new_state_changed (GST_OBJECT_CAST (bin),
old_state, old_next, GST_STATE_VOID_PENDING);
}
GST_STATE_BROADCAST (bin);
return;
}
}
/* handle child messages:
*
* This method is called synchronously when a child posts a message on
* the internal bus.
*
* GST_MESSAGE_EOS: This message is only posted by sinks
* in the PLAYING state. If all sinks posted the EOS message, post
* one upwards.
*
* GST_MESSAGE_STATE_DIRTY: if we are the toplevel bin we do a state
* recalc. If we are not toplevel (we have a parent) we just post
* the message upwards. This makes sure only the toplevel bin will
* run over all its children to check if a state change happened.
*
* GST_MESSAGE_SEGMENT_START: just collect, never forward upwards. If an
* element posts segment_start twice, only the last message is kept.
*
* GST_MESSAGE_SEGMENT_DONE: replace SEGMENT_START message from same poster
* with the segment_done message. If there are no more segment_start
* messages, post segment_done message upwards.
*
* GST_MESSAGE_DURATION: remove all previously cached duration messages.
* Whenever someone performs a duration query on the bin, we store the
* result so we can answer it quicker the next time. Any element that
* changes its duration marks our cached values invalid.
* This message is also posted upwards. This is currently disabled
* because too many elements don't post DURATION messages when the
* duration changes.
*
* GST_MESSAGE_CLOCK_LOST: This message is posted by an element when it
* can no longer provide a clock. The default bin behaviour is to
* check if the lost clock was the one provided by the bin. If so and
* we are currently in the PLAYING state, we forward the message to
* our parent.
* This message is also generated when we remove a clock provider from
* a bin. If this message is received by the application, it should
* PAUSE the pipeline and set it back to PLAYING to force a new clock
* and a new base_time distribution.
*
* GST_MESSAGE_CLOCK_PROVIDE: This message is generated when an element
* can provide a clock. This mostly happens when we add a new clock
* provider to the bin. The default behaviour of the bin is to mark the
* currently selected clock as dirty, which will perform a clock
* recalculation the next time we are asked to provide a clock.
* This message is never sent to the application but is forwarded to
* the parent.
*
* GST_MESSAGE_ASYNC_START: Create an internal ELEMENT message that stores
* the state of the element and the fact that the element will need a
* new base_time.
*
* GST_MESSAGE_ASYNC_DONE: Find the internal ELEMENT message we kept for the
* element when it posted ASYNC_START. If all elements are done, post a
* ASYNC_DONE message to the parent.
*
* OTHER: post upwards.
*/
static void
gst_bin_handle_message_func (GstBin * bin, GstMessage * message)
{
GstObject *src;
GstMessageType type;
src = GST_MESSAGE_SRC (message);
type = GST_MESSAGE_TYPE (message);
GST_DEBUG_OBJECT (bin, "[msg %p] handling child %s message of type %s",
message, GST_ELEMENT_NAME (src), GST_MESSAGE_TYPE_NAME (message));
switch (type) {
case GST_MESSAGE_EOS:
{
gboolean eos;
/* collect all eos messages from the children */
GST_OBJECT_LOCK (bin);
bin_replace_message (bin, message, GST_MESSAGE_EOS);
eos = is_eos (bin);
GST_OBJECT_UNLOCK (bin);
/* if we are completely EOS, we forward an EOS message */
if (eos) {
GST_DEBUG_OBJECT (bin, "all sinks posted EOS");
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_eos (GST_OBJECT_CAST (bin)));
}
break;
}
case GST_MESSAGE_STATE_DIRTY:
{
GST_WARNING_OBJECT (bin, "received deprecated STATE_DIRTY message");
/* free message */
gst_message_unref (message);
break;
}
case GST_MESSAGE_SEGMENT_START:
GST_OBJECT_LOCK (bin);
/* replace any previous segment_start message from this source
* with the new segment start message */
bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
GST_OBJECT_UNLOCK (bin);
break;
case GST_MESSAGE_SEGMENT_DONE:
{
MessageFind find;
gboolean post = FALSE;
GstFormat format;
gint64 position;
gst_message_parse_segment_done (message, &format, &position);
GST_OBJECT_LOCK (bin);
bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
/* if there are no more segment_start messages, everybody posted
* a segment_done and we can post one on the bus. */
/* we don't care who still has a pending segment start */
find.src = NULL;
find.types = GST_MESSAGE_SEGMENT_START;
if (!g_list_find_custom (bin->messages, &find,
(GCompareFunc) message_check)) {
/* nothing found */
post = TRUE;
/* remove all old segment_done messages */
bin_remove_messages (bin, NULL, GST_MESSAGE_SEGMENT_DONE);
}
GST_OBJECT_UNLOCK (bin);
if (post) {
/* post segment done with latest format and position. */
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_segment_done (GST_OBJECT_CAST (bin),
format, position));
}
break;
}
case GST_MESSAGE_DURATION:
{
/* remove all cached duration messages, next time somebody asks
* for duration, we will recalculate. */
GST_OBJECT_LOCK (bin);
bin_remove_messages (bin, NULL, GST_MESSAGE_DURATION);
GST_OBJECT_UNLOCK (bin);
goto forward;
}
case GST_MESSAGE_CLOCK_LOST:
{
GstClock **provided_clock_p;
GstElement **clock_provider_p;
gboolean playing, provided, forward;
GstClock *clock;
gst_message_parse_clock_lost (message, &clock);
GST_OBJECT_LOCK (bin);
bin->clock_dirty = TRUE;
/* if we lost the clock that we provided, post to parent but
* only if we are PLAYING. */
provided = (clock == bin->provided_clock);
playing = (GST_STATE (bin) == GST_STATE_PLAYING);
forward = playing & provided;
if (provided) {
GST_DEBUG_OBJECT (bin,
"Lost clock %" GST_PTR_FORMAT " provided by %" GST_PTR_FORMAT,
bin->provided_clock, bin->clock_provider);
provided_clock_p = &bin->provided_clock;
clock_provider_p = &bin->clock_provider;
gst_object_replace ((GstObject **) provided_clock_p, NULL);
gst_object_replace ((GstObject **) clock_provider_p, NULL);
}
GST_DEBUG_OBJECT (bin, "provided %d, playing %d, forward %d",
provided, playing, forward);
GST_OBJECT_UNLOCK (bin);
if (forward)
goto forward;
/* free message */
gst_message_unref (message);
break;
}
case GST_MESSAGE_CLOCK_PROVIDE:
{
gboolean forward;
GST_OBJECT_LOCK (bin);
bin->clock_dirty = TRUE;
/* a new clock is available, post to parent but not
* to the application */
forward = GST_OBJECT_PARENT (bin) != NULL;
GST_OBJECT_UNLOCK (bin);
if (forward)
goto forward;
/* free message */
gst_message_unref (message);
break;
}
case GST_MESSAGE_ASYNC_START:
{
gboolean forward = FALSE, new_base_time;
GstState target;
GstMessage *smessage = NULL;
GST_DEBUG_OBJECT (bin, "ASYNC_START message %p, %s", message,
GST_OBJECT_NAME (src));
gst_message_parse_async_start (message, &new_base_time);
GST_OBJECT_LOCK (bin);
/* we ignore the message if we are going to <= READY */
target = GST_STATE_TARGET (bin);
if (target <= GST_STATE_READY)
goto ignore_start_message;
bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
bin_handle_async_start (bin, &smessage);
/* prepare an ASYNC_START message */
if (GST_OBJECT_PARENT (bin)) {
forward = TRUE;
message =
gst_message_new_async_start (GST_OBJECT_CAST (bin), new_base_time);
} else {
message = NULL;
}
GST_OBJECT_UNLOCK (bin);
if (smessage)
gst_element_post_message (GST_ELEMENT_CAST (bin), smessage);
if (forward)
goto forward;
else
break;
ignore_start_message:
{
GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
gst_element_state_get_name (target));
GST_OBJECT_UNLOCK (bin);
gst_message_unref (message);
break;
}
}
case GST_MESSAGE_ASYNC_DONE:
{
gboolean done = FALSE, toplevel = FALSE;
GstState target;
MessageFind find;
GstMessage *smessage = NULL;
GST_DEBUG_OBJECT (bin, "ASYNC_DONE message %p, %s", message,
GST_OBJECT_NAME (src));
GST_OBJECT_LOCK (bin);
target = GST_STATE_TARGET (bin);
/* ignore messages if we are shutting down */
if (target <= GST_STATE_READY)
goto ignore_done_message;
bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
/* if there are no more ASYNC_START messages, everybody posted
* a ASYNC_DONE and we can post one on the bus. */
/* we don't care who still has a pending ASYNC_START */
find.src = NULL;
find.types = GST_MESSAGE_ASYNC_START;
if (!g_list_find_custom (bin->messages, &find,
(GCompareFunc) message_check)) {
/* nothing found, remove all old ASYNC_DONE messages */
bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
done = TRUE;
toplevel = GST_OBJECT_PARENT (bin) == NULL;
if (!toplevel)
bin_handle_async_done (bin, &smessage);
}
GST_OBJECT_UNLOCK (bin);
if (smessage) {
GST_DEBUG_OBJECT (bin, "posting state change message");
gst_element_post_message (GST_ELEMENT_CAST (bin), smessage);
}
if (done) {
if (!toplevel) {
GST_DEBUG_OBJECT (bin,
"all async-done, posting ASYNC_DONE to parent");
/* post our combined ASYNC_DONE when all is ASYNC_DONE. */
gst_element_post_message (GST_ELEMENT_CAST (bin),
gst_message_new_async_done (GST_OBJECT_CAST (bin)));
} else {
/* toplevel, start continue state */
GST_DEBUG_OBJECT (bin, "all async-done, starting state continue");
bin_push_state_continue (bin);
}
}
break;
ignore_done_message:
{
GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
gst_element_state_get_name (target));
GST_OBJECT_UNLOCK (bin);
gst_message_unref (message);
break;
}
}
default:
goto forward;
}
return;
forward:
{
/* Send all other messages upward */
GST_DEBUG_OBJECT (bin, "posting message upward");
gst_element_post_message (GST_ELEMENT_CAST (bin), message);
return;
}
}
/* generic struct passed to all query fold methods */
typedef struct
{
GstQuery *query;
gint64 min;
gint64 max;
gboolean live;
} QueryFold;
typedef void (*QueryInitFunction) (GstBin * bin, QueryFold * fold);
typedef void (*QueryDoneFunction) (GstBin * bin, QueryFold * fold);
/* for duration/position we collect all durations/positions and take
* the MAX of all valid results */
static void
bin_query_min_max_init (GstBin * bin, QueryFold * fold)
{
fold->min = 0;
fold->max = -1;
fold->live = FALSE;
}
static gboolean
bin_query_duration_fold (GstElement * item, GValue * ret, QueryFold * fold)
{
if (gst_element_query (item, fold->query)) {
gint64 duration;
g_value_set_boolean (ret, TRUE);
gst_query_parse_duration (fold->query, NULL, &duration);
GST_DEBUG_OBJECT (item, "got duration %" G_GINT64_FORMAT, duration);
if (duration > fold->max)
fold->max = duration;
}
gst_object_unref (item);
return TRUE;
}
static void
bin_query_duration_done (GstBin * bin, QueryFold * fold)
{
GstFormat format;
gst_query_parse_duration (fold->query, &format, NULL);
/* store max in query result */
gst_query_set_duration (fold->query, format, fold->max);
GST_DEBUG_OBJECT (bin, "max duration %" G_GINT64_FORMAT, fold->max);
#ifdef DURATION_CACHING
/* and cache now */
GST_OBJECT_LOCK (bin);
bin->messages = g_list_prepend (bin->messages,
gst_message_new_duration (GST_OBJECT_CAST (bin), format, fold->max));
GST_OBJECT_UNLOCK (bin);
#endif
}
static gboolean
bin_query_position_fold (GstElement * item, GValue * ret, QueryFold * fold)
{
if (gst_element_query (item, fold->query)) {
gint64 position;
g_value_set_boolean (ret, TRUE);
gst_query_parse_position (fold->query, NULL, &position);
GST_DEBUG_OBJECT (item, "got position %" G_GINT64_FORMAT, position);
if (position > fold->max)
fold->max = position;
}
gst_object_unref (item);
return TRUE;
}
static void
bin_query_position_done (GstBin * bin, QueryFold * fold)
{
GstFormat format;
gst_query_parse_position (fold->query, &format, NULL);
/* store max in query result */
gst_query_set_position (fold->query, format, fold->max);
GST_DEBUG_OBJECT (bin, "max position %" G_GINT64_FORMAT, fold->max);
}
static gboolean
bin_query_latency_fold (GstElement * item, GValue * ret, QueryFold * fold)
{
if (gst_element_query (item, fold->query)) {
GstClockTime min, max;
gboolean live;
g_value_set_boolean (ret, TRUE);
gst_query_parse_latency (fold->query, &live, &min, &max);
GST_DEBUG_OBJECT (item,
"got latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
", live %d", GST_TIME_ARGS (min), GST_TIME_ARGS (max), live);
/* for the combined latency we collect the MAX of all min latencies and
* the MIN of all max latencies */
if (min > fold->min)
fold->min = min;
if (fold->max == -1)
fold->max = max;
else if (max < fold->max)
fold->max = max;
if (fold->live == FALSE)
fold->live = live;
}
gst_object_unref (item);
return TRUE;
}
static void
bin_query_latency_done (GstBin * bin, QueryFold * fold)
{
/* store max in query result */
gst_query_set_latency (fold->query, fold->live, fold->min, fold->max);
GST_DEBUG_OBJECT (bin,
"latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
", live %d", GST_TIME_ARGS (fold->min), GST_TIME_ARGS (fold->max),
fold->live);
}
/* generic fold, return first valid result */
static gboolean
bin_query_generic_fold (GstElement * item, GValue * ret, QueryFold * fold)
{
gboolean res;
if ((res = gst_element_query (item, fold->query))) {
g_value_set_boolean (ret, TRUE);
GST_DEBUG_OBJECT (item, "answered query %p", fold->query);
}
gst_object_unref (item);
/* and stop as soon as we have a valid result */
return !res;
}
static gboolean
gst_bin_query (GstElement * element, GstQuery * query)
{
GstBin *bin = GST_BIN (element);
GstIterator *iter;
gboolean res = FALSE;
GstIteratorFoldFunction fold_func;
QueryInitFunction fold_init = NULL;
QueryDoneFunction fold_done = NULL;
QueryFold fold_data;
GValue ret = { 0 };
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_DURATION:
{
#ifdef DURATION_CACHING
GList *cached;
GstFormat qformat;
gst_query_parse_duration (query, &qformat, NULL);
/* find cached duration query */
GST_OBJECT_LOCK (bin);
for (cached = bin->messages; cached; cached = g_list_next (cached)) {
GstMessage *message = (GstMessage *) cached->data;
if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_DURATION &&
GST_MESSAGE_SRC (message) == GST_OBJECT_CAST (bin)) {
GstFormat format;
gint64 duration;
gst_message_parse_duration (message, &format, &duration);
/* if cached same format, copy duration in query result */
if (format == qformat) {
GST_DEBUG_OBJECT (bin, "return cached duration %" G_GINT64_FORMAT,
duration);
GST_OBJECT_UNLOCK (bin);
gst_query_set_duration (query, qformat, duration);
res = TRUE;
goto exit;
}
}
}
GST_OBJECT_UNLOCK (bin);
#endif
/* no cached value found, iterate and collect durations */
fold_func = (GstIteratorFoldFunction) bin_query_duration_fold;
fold_init = bin_query_min_max_init;
fold_done = bin_query_duration_done;
break;
}
case GST_QUERY_POSITION:
{
fold_func = (GstIteratorFoldFunction) bin_query_position_fold;
fold_init = bin_query_min_max_init;
fold_done = bin_query_position_done;
break;
}
case GST_QUERY_LATENCY:
{
fold_func = (GstIteratorFoldFunction) bin_query_latency_fold;
fold_init = bin_query_min_max_init;
fold_done = bin_query_latency_done;
break;
}
default:
fold_func = (GstIteratorFoldFunction) bin_query_generic_fold;
break;
}
fold_data.query = query;
g_value_init (&ret, G_TYPE_BOOLEAN);
g_value_set_boolean (&ret, FALSE);
iter = gst_bin_iterate_sinks (bin);
GST_DEBUG_OBJECT (bin, "Sending query %p (type %s) to sink children",
query, GST_QUERY_TYPE_NAME (query));
if (fold_init)
fold_init (bin, &fold_data);
while (TRUE) {
GstIteratorResult ires;
ires = gst_iterator_fold (iter, fold_func, &ret, &fold_data);
switch (ires) {
case GST_ITERATOR_RESYNC:
gst_iterator_resync (iter);
if (fold_init)
fold_init (bin, &fold_data);
g_value_set_boolean (&ret, FALSE);
break;
case GST_ITERATOR_OK:
case GST_ITERATOR_DONE:
res = g_value_get_boolean (&ret);
if (fold_done != NULL && res)
fold_done (bin, &fold_data);
goto done;
default:
res = FALSE;
goto done;
}
}
done:
gst_iterator_free (iter);
#ifdef DURATION_CACHING
exit:
#endif
GST_DEBUG_OBJECT (bin, "query %p result %d", query, res);
return res;
}
static gint
compare_name (GstElement * element, const gchar * name)
{
gint eq;
GST_OBJECT_LOCK (element);
eq = strcmp (GST_ELEMENT_NAME (element), name);
GST_OBJECT_UNLOCK (element);
if (eq != 0) {
gst_object_unref (element);
}
return eq;
}
/**
* gst_bin_get_by_name:
* @bin: a #GstBin
* @name: the element name to search for
*
* Gets the element with the given name from a bin. This
* function recurses into child bins.
*
* Returns NULL if no element with the given name is found in the bin.
*
* MT safe. Caller owns returned reference.
*
* Returns: the #GstElement with the given name, or NULL
*/
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);
GST_CAT_INFO (GST_CAT_PARENTAGE, "[%s]: looking up child element %s",
GST_ELEMENT_NAME (bin), name);
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: a #GstBin
* @name: the element name to search for
*
* Gets the element with the given name from this bin. If the
* element is not found, a recursion is performed on the parent bin.
*
* Returns NULL if:
* - no element with the given name is found in the bin
*
* MT safe. Caller owns returned reference.
*
* Returns: the #GstElement with the given name, or NULL
*/
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)
{
GType interface_type = (GType) interface;
gint ret;
if (G_TYPE_CHECK_INSTANCE_TYPE (element, interface_type)) {
ret = 0;
} else {
/* we did not find the element, need to release the ref
* added by the iterator */
gst_object_unref (element);
ret = 1;
}
return ret;
}
/**
* gst_bin_get_by_interface:
* @bin: a #GstBin
* @iface: the #GType of an interface
*
* Looks for an 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(). This function recurses into child bins.
*
* MT safe. Caller owns returned reference.
*
* Returns: A #GstElement inside the bin implementing the interface
*/
GstElement *
gst_bin_get_by_interface (GstBin * bin, GType iface)
{
GstIterator *children;
gpointer result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
children = gst_bin_iterate_recurse (bin);
result = gst_iterator_find_custom (children, (GCompareFunc) compare_interface,
(gpointer) iface);
gst_iterator_free (children);
return GST_ELEMENT_CAST (result);
}
/**
* gst_bin_iterate_all_by_interface:
* @bin: a #GstBin
* @iface: the #GType of an 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 inside child bins. The iterator will yield a series
* of #GstElement that should be unreffed after use.
*
* Each element yielded by the iterator will have its refcount increased, so
* unref after use.
*
* MT safe. Caller owns returned value.
*
* Returns: a #GstIterator of #GstElement for all elements in the bin
* implementing the given interface, or NULL
*/
GstIterator *
gst_bin_iterate_all_by_interface (GstBin * bin, GType iface)
{
GstIterator *children;
GstIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
children = gst_bin_iterate_recurse (bin);
result = gst_iterator_filter (children, (GCompareFunc) compare_interface,
(gpointer) iface);
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, (xmlChar *) "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, (xmlChar *) "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 ((char *) field->name, "children")) {
GST_CAT_INFO (GST_CAT_XML, "[%s]: loading children",
GST_ELEMENT_NAME (object));
childlist = field->xmlChildrenNode;
while (childlist) {
if (!strcmp ((char *) childlist->name, "element")) {
/* gst_xml_make_element will gst_bin_add() the element to ourself */
gst_xml_make_element (childlist, GST_OBJECT (bin));
}
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 */
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