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gstreamer/gst/gstbin.c
Thomas Vander Stichele d581d5c976 doc updates 
Original commit message from CVS:

* docs/README:
* docs/gst/gstreamer-sections.txt:
* gst/gstbin.c:
doc updates
* gst/gstregistry.c: (gst_registry_scan_path_level):
fix for a nasty little missed situation where an installed plug-in
which was in the cache did not get overridden by an uninstalled one
which was earlier in the plugin path because the newly created plugin
for the uninstalled one (not in the registry) didn't get its
->registered set to TRUE
2005-11-02 15:34:23 +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 elements, allowing them to be
* managed as a group.
* Pads from the child elements can be ghosted to the bin.
* 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>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,
* 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 and cached. 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>
* </para>
* </refsect2>
*
* Last reviewed on 2005-10-28 (0.9.4)
*/
#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"
GST_DEBUG_CATEGORY_STATIC (bin_debug);
#define GST_CAT_DEFAULT bin_debug
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>");
static void gst_bin_dispose (GObject * object);
static void gst_bin_recalc_state (GstBin * bin, gboolean force);
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 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 void gst_bin_set_clock_func (GstElement * element, GstClock * clock);
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 gst_bin_recalc_func (GstBin * child, gpointer data);
static gint bin_element_is_sink (GstElement * child, 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;
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
};
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");
}
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_LOCK (bin);
if ((res = g_list_nth_data (bin->children, index)))
gst_object_ref (res);
GST_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_LOCK (bin);
num = bin->numchildren;
GST_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);
GST_DEBUG ("creating bin thread pool");
err = NULL;
klass->pool =
g_thread_pool_new ((GFunc) gst_bin_recalc_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->polling = FALSE;
bin->state_dirty = FALSE;
bin->provided_clock = NULL;
bin->clock_dirty = FALSE;
/* Set up a bus for listening to child elements */
bus = g_object_new (gst_bus_get_type (), NULL);
bin->child_bus = bus;
gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bin_bus_handler, bin);
}
/**
* 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_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);
if (element->clock != clock) {
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
*
* The ref of the returned clock in increased so unref after usage.
*
* MT safe
*/
/*
* FIXME, clock selection is not correct here. We should loop the
* elements in state order and pick the last clock we can get. This
* makes sure we get a clock from the source.
*/
static GstClock *
gst_bin_provide_clock_func (GstElement * element)
{
GstClock *result = NULL;
GstBin *bin;
GList *children;
bin = GST_BIN (element);
GST_LOCK (bin);
if (!bin->clock_dirty)
goto not_dirty;
for (children = bin->children; children; children = g_list_next (children)) {
GstElement *child = GST_ELEMENT (children->data);
if ((result = gst_element_provide_clock (child)))
break;
}
gst_object_replace ((GstObject **) & bin->provided_clock,
(GstObject *) result);
bin->clock_dirty = FALSE;
GST_DEBUG_OBJECT (bin, "provided new clock %p", result);
GST_UNLOCK (bin);
return result;
not_dirty:
{
if ((result = bin->provided_clock))
gst_object_ref (result);
GST_DEBUG_OBJECT (bin, "returning old clock %p", result);
GST_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_get_name (GST_MESSAGE_TYPE (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 %s from %s",
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 of types %d", 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 of types %d", types);
}
}
}
/* 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;
/* 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_LOCK (element);
elem_name = g_strdup (GST_ELEMENT_NAME (element));
is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
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 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;
}
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);
gst_element_set_clock (element, GST_ELEMENT_CLOCK (bin));
bin->state_dirty = TRUE;
GST_UNLOCK (bin);
/* 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_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: 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_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;
GstIterator *it;
gboolean is_sink;
GST_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_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_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 (gst_element_provides_clock (element)) {
GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin,
"element \"%s\" could provide a clock", elem_name);
bin->clock_dirty = TRUE;
}
bin->state_dirty = TRUE;
GST_UNLOCK (bin);
GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
elem_name);
g_free (elem_name);
gst_element_set_bus (element, NULL);
/* unlock any waiters for the state change. It is possible that
* we are waiting for an ASYNC state change on this element. The
* element cannot be added to another bin yet as it is not yet
* unparented. */
GST_LOCK (element);
GST_STATE_BROADCAST (element);
GST_UNLOCK (element);
/* 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_LOCK (element);
GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_UNPARENTING);
GST_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_UNLOCK (bin);
g_free (elem_name);
return FALSE;
}
already_removing:
{
GST_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_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_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 (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_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_GET_LOCK (bin),
&bin->children_cookie,
&bin->children,
bin,
(GstIteratorItemFunction) iterate_child_recurse,
(GstIteratorDisposeFunction) gst_object_unref);
GST_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_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_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;
}
/*
* 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;
}
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_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 bemoces 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_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_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_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:
gst_element_commit_state (GST_ELEMENT_CAST (bin));
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, "return now %d",
GST_STATE_RETURN (bin));
return;
not_dirty:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "not dirty");
GST_UNLOCK (bin);
return;
}
was_polling:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "was polling");
GST_UNLOCK (bin);
return;
}
concurrent_state:
{
GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "concurrent_state");
bin->polling = FALSE;
GST_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;
}
}
/***********************************************
* 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; /* has table 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_LOCK (element);
is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK);
GST_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_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_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_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_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);
}
/**
* 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)
{
GstBinSortIterator *result;
g_return_val_if_fail (GST_IS_BIN (bin), NULL);
GST_LOCK (bin);
gst_object_ref (bin);
/* we don't need a NextFunction because we ref the items in the _next
* method already */
result = (GstBinSortIterator *)
gst_iterator_new (sizeof (GstBinSortIterator),
GST_TYPE_ELEMENT,
GST_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);
result->bin = bin;
gst_bin_sort_iterator_resync (result);
GST_UNLOCK (bin);
return (GstIterator *) result;
}
static GstStateChangeReturn
gst_bin_element_set_state (GstBin * bin, GstElement * element, GstState pending)
{
GstStateChangeReturn ret;
gboolean locked;
/* peel off the locked flag */
GST_LOCK (element);
locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
GST_UNLOCK (element);
/* skip locked elements */
if (G_UNLIKELY (locked)) {
ret = GST_STATE_CHANGE_SUCCESS;
goto done;
}
/* change state */
ret = gst_element_set_state (element, pending);
done:
return ret;
}
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 = GST_STATE_TRANSITION_CURRENT (transition);
next = 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);
/* Clear message list on next PAUSED */
if (next == GST_STATE_PAUSED) {
GST_LOCK (bin);
GST_DEBUG_OBJECT (element, "clearing EOS elements");
bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
GST_UNLOCK (bin);
}
/* 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 base time on child */
gst_element_set_base_time (child, base_time);
/* set state now */
ret = gst_bin_element_set_state (bin, child, 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",
GST_ELEMENT_NAME (child));
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;
break;
default:
case GST_ITERATOR_DONE:
GST_CAT_DEBUG (GST_CAT_STATES, "iterator done");
done = TRUE;
break;
}
}
ret = parent_class->change_state (element, transition);
if (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 %d",
gst_element_state_get_name (current),
gst_element_state_get_name (next),
gst_element_state_get_name (GST_STATE (element)), ret);
return ret;
}
static void
gst_bin_dispose (GObject * object)
{
GstBin *bin = GST_BIN (object);
GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
gst_object_unref (bin->child_bus);
bin->child_bus = NULL;
gst_object_replace ((GstObject **) & bin->provided_clock, 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);
}
/*
* 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 (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 void
gst_bin_recalc_func (GstBin * bin, gpointer data)
{
GST_DEBUG_OBJECT (bin, "doing state recalc");
GST_STATE_LOCK (bin);
gst_bin_recalc_state (bin, FALSE);
GST_STATE_UNLOCK (bin);
GST_DEBUG_OBJECT (bin, "state recalc done");
gst_object_unref (bin);
}
/* handle child messages:
*
* 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.
*
* 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.
*
* OTHER: post upwards.
*/
static GstBusSyncReply
bin_bus_handler (GstBus * bus, GstMessage * message, GstBin * bin)
{
GST_DEBUG_OBJECT (bin, "[msg %p] handling child message of type %s",
message, gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
switch (GST_MESSAGE_TYPE (message)) {
case GST_MESSAGE_EOS:
{
gboolean eos;
/* collect all eos messages from the children */
GST_LOCK (bin);
bin_replace_message (bin, message, GST_MESSAGE_EOS);
eos = is_eos (bin);
GST_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:
{
GstObject *src;
GstBinClass *klass;
src = GST_MESSAGE_SRC (message);
GST_DEBUG_OBJECT (bin, "%s gave state dirty", GST_ELEMENT_NAME (src));
/* mark the bin dirty */
GST_LOCK (bin);
GST_DEBUG_OBJECT (bin, "marking dirty");
bin->state_dirty = TRUE;
if (GST_OBJECT_PARENT (bin))
goto not_toplevel;
/* free message */
gst_message_unref (message);
klass = GST_BIN_GET_CLASS (bin);
gst_object_ref (bin);
GST_DEBUG_OBJECT (bin, "pushing recalc on thread pool");
g_thread_pool_push (klass->pool, bin, NULL);
GST_UNLOCK (bin);
break;
/* non toplevel bins just forward the message and don't start
* a recalc themselves */
not_toplevel:
{
GST_UNLOCK (bin);
GST_DEBUG_OBJECT (bin, "not toplevel");
/* post message up, mark parent bins dirty */
gst_element_post_message (GST_ELEMENT_CAST (bin), message);
break;
}
}
case GST_MESSAGE_SEGMENT_START:
GST_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_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_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_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_LOCK (bin);
bin_remove_messages (bin, NULL, GST_MESSAGE_DURATION);
GST_UNLOCK (bin);
/* fallthrough */
}
default:
/* Send all other messages upward */
GST_DEBUG_OBJECT (bin, "posting message upward");
gst_element_post_message (GST_ELEMENT_CAST (bin), message);
break;
}
return GST_BUS_DROP;
}
/* generic struct passed to all query fold methods */
typedef struct
{
GstQuery *query;
gint64 max;
} QueryFold;
typedef void (*QueryInitFunction) (GstBin * bin, QueryFold * fold);
typedef void (*QueryDoneFunction) (GstBin * bin, QueryFold * fold);
/* for duration we collect all durations and take the MAX of
* all valid results */
static void
bin_query_duration_init (GstBin * bin, QueryFold * fold)
{
fold->max = -1;
}
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;
}
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);
/* and cache now */
GST_LOCK (bin);
bin->messages = g_list_prepend (bin->messages,
gst_message_new_duration (GST_OBJECT_CAST (bin), format, fold->max));
GST_UNLOCK (bin);
}
/* 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);
}
/* 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:
{
GList *cached;
GstFormat qformat;
gst_query_parse_duration (query, &qformat, NULL);
/* find cached duration query */
GST_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_UNLOCK (bin);
gst_query_set_duration (query, qformat, duration);
res = TRUE;
goto exit;
}
}
}
GST_UNLOCK (bin);
fold_func = (GstIteratorFoldFunction) bin_query_duration_fold;
fold_init = bin_query_duration_init;
fold_done = bin_query_duration_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 %d) to sink children",
query, GST_QUERY_TYPE (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);
exit:
GST_DEBUG_OBJECT (bin, "query %p result %d", query, res);
return res;
}
static gint
compare_name (GstElement * element, const gchar * name)
{
gint eq;
GST_LOCK (element);
eq = strcmp (GST_ELEMENT_NAME (element), name);
GST_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)
{
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 (element);
ret = 1;
}
return ret;
}
/**
* gst_bin_get_by_interface:
* @bin: a #GstBin
* @interface: 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 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_iterate_all_by_interface:
* @bin: a #GstBin
* @interface: 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 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, (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")) {
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 (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 */
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