/* GStreamer * * Copyright (C) 1999,2000 Erik Walthinsen * 2004 Wim Taymans * * 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 element-added signal is * fired whenever a new element is added to the bin. Likewise the element-removed signal is fired * whenever an element is removed from the bin. * * Notes * * A #GstBin internally intercepts every #GstMessage posted by its children and * implements the following default behaviour for each of them: * * * GST_MESSAGE_EOS * 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. * * * GST_MESSAGE_SEGMENT_START * just collected and never forwarded upwards. * The messages are used to decide when all elements have completed playback * of their segment. * * * GST_MESSAGE_SEGMENT_DONE * Is posted by #GstBin when all elements that posted * a SEGMENT_START have posted a SEGMENT_DONE. * * * GST_MESSAGE_DURATION * 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. * * * * 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 * 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. * * * * GST_MESSAGE_CLOCK_PROVIDE * 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. * * * * OTHERS * posted upwards. * * * * * A #GstBin implements the following default behaviour for answering to a * #GstQuery: * * * GST_QUERY_DURATION * 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. * * * * OTHERS * 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. * * * * 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. * * * * * 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. * #define DURATION_CACHING */ 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 ," "Wim Taymans "); 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 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_recalc_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; 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"); } 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_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 = 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 %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 type %d", 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)); 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_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; GstMessage *clock_message = NULL; 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); } bin->state_dirty = TRUE; GST_OBJECT_UNLOCK (bin); if (clock_message) { gst_element_post_message (GST_ELEMENT_CAST (bin), clock_message); } 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; } /* * 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_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_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 %d", 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; } } /*********************************************** * 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, GstState pending) { GstStateChangeReturn ret; gboolean locked; /* 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)) { GST_DEBUG_OBJECT (element, "element is locked, pretending state change succeeded"); ret = GST_STATE_CHANGE_SUCCESS; goto done; } /* change state */ ret = gst_element_set_state (element, pending); done: return ret; } /* gst_iterator_fold functions for pads_activate * Note how we don't stop the iterator when we fail an activation. This is * probably a FIXME since when one pad activation fails, we don't want to * continue our state change. */ static gboolean activate_pads (GstPad * pad, GValue * ret, gboolean * active) { if (!gst_pad_set_active (pad, *active)) g_value_set_boolean (ret, FALSE); 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 = 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); 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 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; 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_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); } 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; } /* 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 * 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. * * OTHER: post upwards. */ static void gst_bin_handle_message_func (GstBin * bin, GstMessage * message) { GST_DEBUG_OBJECT (bin, "[msg %p] handling child message of type %s", message, GST_MESSAGE_TYPE_NAME (message)); switch (GST_MESSAGE_TYPE (message)) { 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: { 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_OBJECT_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); if (!bin->polling) { GST_DEBUG_OBJECT (bin, "pushing recalc on thread pool"); gst_object_ref (bin); g_thread_pool_push (klass->pool, bin, NULL); } else { GST_DEBUG_OBJECT (bin, "state recalc already in progress, not pushing new recalc"); } GST_OBJECT_UNLOCK (bin); break; /* non toplevel bins just forward the message and don't start * a recalc themselves */ not_toplevel: { GST_OBJECT_UNLOCK (bin); GST_DEBUG_OBJECT (bin, "not toplevel, forwarding"); goto forward; } } 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; } 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 max; } 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_max_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; } 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); } /* 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_max_init; fold_done = bin_query_duration_done; break; } case GST_QUERY_POSITION: { fold_func = (GstIteratorFoldFunction) bin_query_position_fold; fold_init = bin_query_max_init; fold_done = bin_query_position_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_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 * @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; gpointer result; g_return_val_if_fail (GST_IS_BIN (bin), NULL); g_return_val_if_fail (G_TYPE_IS_INTERFACE (interface), NULL); children = gst_bin_iterate_recurse (bin); result = gst_iterator_find_custom (children, (GCompareFunc) compare_interface, (gpointer) 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); g_return_val_if_fail (G_TYPE_IS_INTERFACE (interface), NULL); children = gst_bin_iterate_recurse (bin); result = gst_iterator_filter (children, (GCompareFunc) compare_interface, (gpointer) 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")) { /* 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 */