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2108c6228a
Between getting the GSource with the mutex and destroying it, something else might've destroyed it already and we would have a dangling pointer. Keep an additional reference just in case.
1486 lines
42 KiB
C
1486 lines
42 KiB
C
/* GStreamer
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* Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
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*
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* gstbus.c: GstBus subsystem
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/**
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* SECTION:gstbus
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* @title: GstBus
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* @short_description: Asynchronous message bus subsystem
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* @see_also: #GstMessage, #GstElement
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*
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* The #GstBus is an object responsible for delivering #GstMessage packets in
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* a first-in first-out way from the streaming threads (see #GstTask) to the
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* application.
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*
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* Since the application typically only wants to deal with delivery of these
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* messages from one thread, the GstBus will marshall the messages between
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* different threads. This is important since the actual streaming of media
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* is done in another thread than the application.
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*
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* The GstBus provides support for #GSource based notifications. This makes it
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* possible to handle the delivery in the glib mainloop.
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*
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* The #GSource callback function gst_bus_async_signal_func() can be used to
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* convert all bus messages into signal emissions.
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*
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* A message is posted on the bus with the gst_bus_post() method. With the
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* gst_bus_peek() and gst_bus_pop() methods one can look at or retrieve a
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* previously posted message.
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*
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* The bus can be polled with the gst_bus_poll() method. This methods blocks
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* up to the specified timeout value until one of the specified messages types
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* is posted on the bus. The application can then gst_bus_pop() the messages
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* from the bus to handle them.
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* Alternatively the application can register an asynchronous bus function
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* using gst_bus_add_watch_full() or gst_bus_add_watch(). This function will
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* install a #GSource in the default glib main loop and will deliver messages
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* a short while after they have been posted. Note that the main loop should
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* be running for the asynchronous callbacks.
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*
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* It is also possible to get messages from the bus without any thread
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* marshalling with the gst_bus_set_sync_handler() method. This makes it
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* possible to react to a message in the same thread that posted the
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* message on the bus. This should only be used if the application is able
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* to deal with messages from different threads.
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*
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* Every #GstPipeline has one bus.
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*
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* Note that a #GstPipeline will set its bus into flushing state when changing
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* from READY to NULL state.
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*/
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#include "gst_private.h"
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#include <errno.h>
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif
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#include <sys/types.h>
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#include "gstatomicqueue.h"
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#include "gstinfo.h"
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#include "gstpoll.h"
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#include "gstbus.h"
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#include "glib-compat-private.h"
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#ifdef G_OS_WIN32
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# ifndef EWOULDBLOCK
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# define EWOULDBLOCK EAGAIN /* This is just to placate gcc */
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# endif
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#endif /* G_OS_WIN32 */
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#define GST_CAT_DEFAULT GST_CAT_BUS
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/* bus signals */
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enum
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{
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SYNC_MESSAGE,
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ASYNC_MESSAGE,
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/* add more above */
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LAST_SIGNAL
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};
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#define DEFAULT_ENABLE_ASYNC (TRUE)
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enum
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{
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PROP_0,
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PROP_ENABLE_ASYNC
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};
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static void gst_bus_dispose (GObject * object);
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static void gst_bus_finalize (GObject * object);
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static guint gst_bus_signals[LAST_SIGNAL] = { 0 };
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struct _GstBusPrivate
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{
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GstAtomicQueue *queue;
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GMutex queue_lock;
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GstBusSyncHandler sync_handler;
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gpointer sync_handler_data;
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GDestroyNotify sync_handler_notify;
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guint num_signal_watchers;
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guint num_sync_message_emitters;
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GSource *signal_watch;
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gboolean enable_async;
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GstPoll *poll;
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GPollFD pollfd;
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};
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#define gst_bus_parent_class parent_class
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G_DEFINE_TYPE_WITH_PRIVATE (GstBus, gst_bus, GST_TYPE_OBJECT);
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static void
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gst_bus_set_property (GObject * object,
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guint prop_id, const GValue * value, GParamSpec * pspec)
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{
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GstBus *bus = GST_BUS_CAST (object);
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switch (prop_id) {
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case PROP_ENABLE_ASYNC:
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bus->priv->enable_async = g_value_get_boolean (value);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static void
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gst_bus_constructed (GObject * object)
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{
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GstBus *bus = GST_BUS_CAST (object);
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if (bus->priv->enable_async) {
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bus->priv->poll = gst_poll_new_timer ();
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gst_poll_get_read_gpollfd (bus->priv->poll, &bus->priv->pollfd);
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}
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G_OBJECT_CLASS (gst_bus_parent_class)->constructed (object);
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}
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static void
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gst_bus_class_init (GstBusClass * klass)
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{
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GObjectClass *gobject_class = (GObjectClass *) klass;
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gobject_class->dispose = gst_bus_dispose;
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gobject_class->finalize = gst_bus_finalize;
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gobject_class->set_property = gst_bus_set_property;
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gobject_class->constructed = gst_bus_constructed;
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/**
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* GstBus::enable-async:
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*
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* Enable async message delivery support for bus watches,
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* gst_bus_pop() and similar API. Without this only the
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* synchronous message handlers are called.
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*
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* This property is used to create the child element buses
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* in #GstBin.
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*/
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g_object_class_install_property (gobject_class, PROP_ENABLE_ASYNC,
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g_param_spec_boolean ("enable-async", "Enable Async",
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"Enable async message delivery for bus watches and gst_bus_pop()",
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DEFAULT_ENABLE_ASYNC,
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G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
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/**
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* GstBus::sync-message:
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* @bus: the object which received the signal
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* @message: the message that has been posted synchronously
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*
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* A message has been posted on the bus. This signal is emitted from the
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* thread that posted the message so one has to be careful with locking.
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*
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* This signal will not be emitted by default, you have to call
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* gst_bus_enable_sync_message_emission() before.
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*/
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gst_bus_signals[SYNC_MESSAGE] =
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g_signal_new ("sync-message", G_TYPE_FROM_CLASS (klass),
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G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
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G_STRUCT_OFFSET (GstBusClass, sync_message), NULL, NULL,
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g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
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/**
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* GstBus::message:
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* @bus: the object which received the signal
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* @message: the message that has been posted asynchronously
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*
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* A message has been posted on the bus. This signal is emitted from a
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* GSource added to the mainloop. this signal will only be emitted when
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* there is a mainloop running.
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*/
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gst_bus_signals[ASYNC_MESSAGE] =
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g_signal_new ("message", G_TYPE_FROM_CLASS (klass),
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G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
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G_STRUCT_OFFSET (GstBusClass, message), NULL, NULL,
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g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
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}
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static void
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gst_bus_init (GstBus * bus)
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{
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bus->priv = gst_bus_get_instance_private (bus);
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bus->priv->enable_async = DEFAULT_ENABLE_ASYNC;
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g_mutex_init (&bus->priv->queue_lock);
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bus->priv->queue = gst_atomic_queue_new (32);
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GST_DEBUG_OBJECT (bus, "created");
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}
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static void
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gst_bus_dispose (GObject * object)
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{
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GstBus *bus = GST_BUS (object);
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if (bus->priv->queue) {
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GstMessage *message;
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g_mutex_lock (&bus->priv->queue_lock);
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do {
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message = gst_atomic_queue_pop (bus->priv->queue);
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if (message)
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gst_message_unref (message);
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} while (message != NULL);
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gst_atomic_queue_unref (bus->priv->queue);
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bus->priv->queue = NULL;
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g_mutex_unlock (&bus->priv->queue_lock);
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g_mutex_clear (&bus->priv->queue_lock);
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if (bus->priv->poll)
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gst_poll_free (bus->priv->poll);
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bus->priv->poll = NULL;
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}
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G_OBJECT_CLASS (parent_class)->dispose (object);
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}
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static void
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gst_bus_finalize (GObject * object)
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{
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GstBus *bus = GST_BUS (object);
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if (bus->priv->sync_handler_notify)
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bus->priv->sync_handler_notify (bus->priv->sync_handler_data);
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G_OBJECT_CLASS (parent_class)->finalize (object);
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}
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/**
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* gst_bus_new:
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*
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* Creates a new #GstBus instance.
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*
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* Returns: (transfer full): a new #GstBus instance
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*/
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GstBus *
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gst_bus_new (void)
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{
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GstBus *result;
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result = g_object_new (gst_bus_get_type (), NULL);
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GST_DEBUG_OBJECT (result, "created new bus");
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/* clear floating flag */
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gst_object_ref_sink (result);
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return result;
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}
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/**
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* gst_bus_post:
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* @bus: a #GstBus to post on
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* @message: (transfer full): the #GstMessage to post
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*
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* Post a message on the given bus. Ownership of the message
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* is taken by the bus.
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*
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* Returns: %TRUE if the message could be posted, %FALSE if the bus is flushing.
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*
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* MT safe.
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*/
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gboolean
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gst_bus_post (GstBus * bus, GstMessage * message)
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{
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GstBusSyncReply reply = GST_BUS_PASS;
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GstBusSyncHandler handler;
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gboolean emit_sync_message;
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gpointer handler_data;
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g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
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g_return_val_if_fail (GST_IS_MESSAGE (message), FALSE);
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GST_DEBUG_OBJECT (bus, "[msg %p] posting on bus %" GST_PTR_FORMAT, message,
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message);
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/* check we didn't accidentally add a public flag that maps to same value */
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g_assert (!GST_MINI_OBJECT_FLAG_IS_SET (message,
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GST_MESSAGE_FLAG_ASYNC_DELIVERY));
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GST_OBJECT_LOCK (bus);
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/* check if the bus is flushing */
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if (GST_OBJECT_FLAG_IS_SET (bus, GST_BUS_FLUSHING))
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goto is_flushing;
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handler = bus->priv->sync_handler;
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handler_data = bus->priv->sync_handler_data;
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emit_sync_message = bus->priv->num_sync_message_emitters > 0;
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GST_OBJECT_UNLOCK (bus);
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/* first call the sync handler if it is installed */
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if (handler)
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reply = handler (bus, message, handler_data);
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/* emit sync-message if requested to do so via
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gst_bus_enable_sync_message_emission. terrible but effective */
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if (emit_sync_message && reply != GST_BUS_DROP
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&& handler != gst_bus_sync_signal_handler)
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gst_bus_sync_signal_handler (bus, message, NULL);
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/* If this is a bus without async message delivery
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* always drop the message */
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if (!bus->priv->poll)
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reply = GST_BUS_DROP;
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/* now see what we should do with the message */
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switch (reply) {
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case GST_BUS_DROP:
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/* drop the message */
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GST_DEBUG_OBJECT (bus, "[msg %p] dropped", message);
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break;
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case GST_BUS_PASS:
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/* pass the message to the async queue, refcount passed in the queue */
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GST_DEBUG_OBJECT (bus, "[msg %p] pushing on async queue", message);
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gst_atomic_queue_push (bus->priv->queue, message);
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gst_poll_write_control (bus->priv->poll);
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GST_DEBUG_OBJECT (bus, "[msg %p] pushed on async queue", message);
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break;
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case GST_BUS_ASYNC:
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{
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/* async delivery, we need a mutex and a cond to block
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* on */
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GCond *cond = GST_MESSAGE_GET_COND (message);
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GMutex *lock = GST_MESSAGE_GET_LOCK (message);
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g_cond_init (cond);
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g_mutex_init (lock);
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GST_MINI_OBJECT_FLAG_SET (message, GST_MESSAGE_FLAG_ASYNC_DELIVERY);
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GST_DEBUG_OBJECT (bus, "[msg %p] waiting for async delivery", message);
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/* now we lock the message mutex, send the message to the async
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* queue. When the message is handled by the app and destroyed,
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* the cond will be signalled and we can continue */
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g_mutex_lock (lock);
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gst_atomic_queue_push (bus->priv->queue, message);
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gst_poll_write_control (bus->priv->poll);
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/* now block till the message is freed */
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g_cond_wait (cond, lock);
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/* we acquired a new ref from gst_message_dispose() so we can clean up */
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g_mutex_unlock (lock);
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GST_DEBUG_OBJECT (bus, "[msg %p] delivered asynchronously", message);
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GST_MINI_OBJECT_FLAG_UNSET (message, GST_MESSAGE_FLAG_ASYNC_DELIVERY);
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g_mutex_clear (lock);
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g_cond_clear (cond);
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gst_message_unref (message);
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break;
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}
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default:
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g_warning ("invalid return from bus sync handler");
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break;
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}
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return TRUE;
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/* ERRORS */
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is_flushing:
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{
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GST_DEBUG_OBJECT (bus, "bus is flushing");
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GST_OBJECT_UNLOCK (bus);
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gst_message_unref (message);
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return FALSE;
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}
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}
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/**
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* gst_bus_have_pending:
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* @bus: a #GstBus to check
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*
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* Check if there are pending messages on the bus that
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* should be handled.
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*
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* Returns: %TRUE if there are messages on the bus to be handled, %FALSE
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* otherwise.
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*
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* MT safe.
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*/
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gboolean
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gst_bus_have_pending (GstBus * bus)
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{
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gboolean result;
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g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
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/* see if there is a message on the bus */
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result = gst_atomic_queue_length (bus->priv->queue) != 0;
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return result;
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}
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/**
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* gst_bus_set_flushing:
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* @bus: a #GstBus
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* @flushing: whether or not to flush the bus
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*
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* If @flushing, flush out and unref any messages queued in the bus. Releases
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* references to the message origin objects. Will flush future messages until
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* gst_bus_set_flushing() sets @flushing to %FALSE.
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*
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* MT safe.
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*/
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void
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gst_bus_set_flushing (GstBus * bus, gboolean flushing)
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{
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GstMessage *message;
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GList *message_list = NULL;
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g_return_if_fail (GST_IS_BUS (bus));
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GST_OBJECT_LOCK (bus);
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if (flushing) {
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GST_OBJECT_FLAG_SET (bus, GST_BUS_FLUSHING);
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GST_DEBUG_OBJECT (bus, "set bus flushing");
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while ((message = gst_bus_pop (bus)))
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message_list = g_list_prepend (message_list, message);
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} else {
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GST_DEBUG_OBJECT (bus, "unset bus flushing");
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GST_OBJECT_FLAG_UNSET (bus, GST_BUS_FLUSHING);
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}
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GST_OBJECT_UNLOCK (bus);
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g_list_free_full (message_list, (GDestroyNotify) gst_message_unref);
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}
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/**
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* gst_bus_timed_pop_filtered:
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* @bus: a #GstBus to pop from
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* @timeout: a timeout in nanoseconds, or GST_CLOCK_TIME_NONE to wait forever
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* @types: message types to take into account, GST_MESSAGE_ANY for any type
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*
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* Get a message from the bus whose type matches the message type mask @types,
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* waiting up to the specified timeout (and discarding any messages that do not
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* match the mask provided).
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*
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* If @timeout is 0, this function behaves like gst_bus_pop_filtered(). If
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* @timeout is #GST_CLOCK_TIME_NONE, this function will block forever until a
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* matching message was posted on the bus.
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*
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* Returns: (transfer full) (nullable): a #GstMessage matching the
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* filter in @types, or %NULL if no matching message was found on
|
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* the bus until the timeout expired. The message is taken from
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* the bus and needs to be unreffed with gst_message_unref() after
|
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* usage.
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*
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* MT safe.
|
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*/
|
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GstMessage *
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gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout,
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GstMessageType types)
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|
{
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GstMessage *message;
|
|
GTimeVal now, then;
|
|
gboolean first_round = TRUE;
|
|
GstClockTime elapsed = 0;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
g_return_val_if_fail (types != 0, NULL);
|
|
g_return_val_if_fail (timeout == 0 || bus->priv->poll != NULL, NULL);
|
|
|
|
g_mutex_lock (&bus->priv->queue_lock);
|
|
|
|
while (TRUE) {
|
|
gint ret;
|
|
|
|
GST_LOG_OBJECT (bus, "have %d messages",
|
|
gst_atomic_queue_length (bus->priv->queue));
|
|
|
|
while ((message = gst_atomic_queue_pop (bus->priv->queue))) {
|
|
if (bus->priv->poll) {
|
|
while (!gst_poll_read_control (bus->priv->poll)) {
|
|
if (errno == EWOULDBLOCK) {
|
|
/* Retry, this can happen if pushing to the queue has finished,
|
|
* popping here succeeded but writing control did not finish
|
|
* before we got to this line. */
|
|
/* Give other threads the chance to do something */
|
|
g_thread_yield ();
|
|
continue;
|
|
} else {
|
|
/* This is a real error and means that either the bus is in an
|
|
* inconsistent state, or the GstPoll is invalid. GstPoll already
|
|
* prints a critical warning about this, no need to do that again
|
|
* ourselves */
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
GST_DEBUG_OBJECT (bus, "got message %p, %s from %s, type mask is %u",
|
|
message, GST_MESSAGE_TYPE_NAME (message),
|
|
GST_MESSAGE_SRC_NAME (message), (guint) types);
|
|
if ((GST_MESSAGE_TYPE (message) & types) != 0) {
|
|
/* Extra check to ensure extended types don't get matched unless
|
|
* asked for */
|
|
if ((!GST_MESSAGE_TYPE_IS_EXTENDED (message))
|
|
|| (types & GST_MESSAGE_EXTENDED)) {
|
|
/* exit the loop, we have a message */
|
|
goto beach;
|
|
}
|
|
}
|
|
|
|
GST_DEBUG_OBJECT (bus, "discarding message, does not match mask");
|
|
gst_message_unref (message);
|
|
message = NULL;
|
|
}
|
|
|
|
/* no need to wait, exit loop */
|
|
if (timeout == 0)
|
|
break;
|
|
|
|
else if (timeout != GST_CLOCK_TIME_NONE) {
|
|
if (first_round) {
|
|
g_get_current_time (&then);
|
|
first_round = FALSE;
|
|
} else {
|
|
g_get_current_time (&now);
|
|
|
|
elapsed = GST_TIMEVAL_TO_TIME (now) - GST_TIMEVAL_TO_TIME (then);
|
|
|
|
if (elapsed > timeout)
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* only here in timeout case */
|
|
g_assert (bus->priv->poll);
|
|
g_mutex_unlock (&bus->priv->queue_lock);
|
|
ret = gst_poll_wait (bus->priv->poll, timeout - elapsed);
|
|
g_mutex_lock (&bus->priv->queue_lock);
|
|
|
|
if (ret == 0) {
|
|
GST_INFO_OBJECT (bus, "timed out, breaking loop");
|
|
break;
|
|
} else {
|
|
GST_INFO_OBJECT (bus, "we got woken up, recheck for message");
|
|
}
|
|
}
|
|
|
|
beach:
|
|
|
|
g_mutex_unlock (&bus->priv->queue_lock);
|
|
|
|
return message;
|
|
}
|
|
|
|
|
|
/**
|
|
* gst_bus_timed_pop:
|
|
* @bus: a #GstBus to pop
|
|
* @timeout: a timeout
|
|
*
|
|
* Get a message from the bus, waiting up to the specified timeout.
|
|
*
|
|
* If @timeout is 0, this function behaves like gst_bus_pop(). If @timeout is
|
|
* #GST_CLOCK_TIME_NONE, this function will block forever until a message was
|
|
* posted on the bus.
|
|
*
|
|
* Returns: (transfer full) (nullable): the #GstMessage that is on the
|
|
* bus after the specified timeout or %NULL if the bus is empty
|
|
* after the timeout expired. The message is taken from the bus
|
|
* and needs to be unreffed with gst_message_unref() after usage.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
GstMessage *
|
|
gst_bus_timed_pop (GstBus * bus, GstClockTime timeout)
|
|
{
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
|
|
return gst_bus_timed_pop_filtered (bus, timeout, GST_MESSAGE_ANY);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_pop_filtered:
|
|
* @bus: a #GstBus to pop
|
|
* @types: message types to take into account
|
|
*
|
|
* Get a message matching @type from the bus. Will discard all messages on
|
|
* the bus that do not match @type and that have been posted before the first
|
|
* message that does match @type. If there is no message matching @type on
|
|
* the bus, all messages will be discarded. It is not possible to use message
|
|
* enums beyond #GST_MESSAGE_EXTENDED in the @events mask.
|
|
*
|
|
* Returns: (transfer full) (nullable): the next #GstMessage matching
|
|
* @type that is on the bus, or %NULL if the bus is empty or there
|
|
* is no message matching @type. The message is taken from the bus
|
|
* and needs to be unreffed with gst_message_unref() after usage.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
GstMessage *
|
|
gst_bus_pop_filtered (GstBus * bus, GstMessageType types)
|
|
{
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
g_return_val_if_fail (types != 0, NULL);
|
|
|
|
return gst_bus_timed_pop_filtered (bus, 0, types);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_pop:
|
|
* @bus: a #GstBus to pop
|
|
*
|
|
* Get a message from the bus.
|
|
*
|
|
* Returns: (transfer full) (nullable): the #GstMessage that is on the
|
|
* bus, or %NULL if the bus is empty. The message is taken from
|
|
* the bus and needs to be unreffed with gst_message_unref() after
|
|
* usage.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
GstMessage *
|
|
gst_bus_pop (GstBus * bus)
|
|
{
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
|
|
return gst_bus_timed_pop_filtered (bus, 0, GST_MESSAGE_ANY);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_peek:
|
|
* @bus: a #GstBus
|
|
*
|
|
* Peek the message on the top of the bus' queue. The message will remain
|
|
* on the bus' message queue. A reference is returned, and needs to be unreffed
|
|
* by the caller.
|
|
*
|
|
* Returns: (transfer full) (nullable): the #GstMessage that is on the
|
|
* bus, or %NULL if the bus is empty.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
GstMessage *
|
|
gst_bus_peek (GstBus * bus)
|
|
{
|
|
GstMessage *message;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
|
|
g_mutex_lock (&bus->priv->queue_lock);
|
|
message = gst_atomic_queue_peek (bus->priv->queue);
|
|
if (message)
|
|
gst_message_ref (message);
|
|
g_mutex_unlock (&bus->priv->queue_lock);
|
|
|
|
GST_DEBUG_OBJECT (bus, "peek on bus, got message %p", message);
|
|
|
|
return message;
|
|
}
|
|
|
|
/**
|
|
* gst_bus_set_sync_handler:
|
|
* @bus: a #GstBus to install the handler on
|
|
* @func: (allow-none): The handler function to install
|
|
* @user_data: User data that will be sent to the handler function.
|
|
* @notify: called when @user_data becomes unused
|
|
*
|
|
* Sets the synchronous handler on the bus. The function will be called
|
|
* every time a new message is posted on the bus. Note that the function
|
|
* will be called in the same thread context as the posting object. This
|
|
* function is usually only called by the creator of the bus. Applications
|
|
* should handle messages asynchronously using the gst_bus watch and poll
|
|
* functions.
|
|
*
|
|
* You cannot replace an existing sync_handler. You can pass %NULL to this
|
|
* function, which will clear the existing handler.
|
|
*/
|
|
void
|
|
gst_bus_set_sync_handler (GstBus * bus, GstBusSyncHandler func,
|
|
gpointer user_data, GDestroyNotify notify)
|
|
{
|
|
GDestroyNotify old_notify;
|
|
|
|
g_return_if_fail (GST_IS_BUS (bus));
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
/* Assert if the user attempts to replace an existing sync_handler,
|
|
* other than to clear it */
|
|
if (func != NULL && bus->priv->sync_handler != NULL)
|
|
goto no_replace;
|
|
|
|
if ((old_notify = bus->priv->sync_handler_notify)) {
|
|
gpointer old_data = bus->priv->sync_handler_data;
|
|
|
|
bus->priv->sync_handler_data = NULL;
|
|
bus->priv->sync_handler_notify = NULL;
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
old_notify (old_data);
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
}
|
|
bus->priv->sync_handler = func;
|
|
bus->priv->sync_handler_data = user_data;
|
|
bus->priv->sync_handler_notify = notify;
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
return;
|
|
|
|
no_replace:
|
|
{
|
|
GST_OBJECT_UNLOCK (bus);
|
|
g_warning ("cannot replace existing sync handler");
|
|
return;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* gst_bus_get_pollfd:
|
|
* @bus: A #GstBus
|
|
* @fd: (out): A GPollFD to fill
|
|
*
|
|
* Gets the file descriptor from the bus which can be used to get notified about
|
|
* messages being available with functions like g_poll(), and allows integration
|
|
* into other event loops based on file descriptors.
|
|
* Whenever a message is available, the POLLIN / %G_IO_IN event is set.
|
|
*
|
|
* Warning: NEVER read or write anything to the returned fd but only use it
|
|
* for getting notifications via g_poll() or similar and then use the normal
|
|
* GstBus API, e.g. gst_bus_pop().
|
|
*
|
|
* Since: 1.14
|
|
*/
|
|
void
|
|
gst_bus_get_pollfd (GstBus * bus, GPollFD * fd)
|
|
{
|
|
g_return_if_fail (GST_IS_BUS (bus));
|
|
g_return_if_fail (bus->priv->poll != NULL);
|
|
|
|
*fd = bus->priv->pollfd;
|
|
}
|
|
|
|
/* GSource for the bus
|
|
*/
|
|
typedef struct
|
|
{
|
|
GSource source;
|
|
GstBus *bus;
|
|
} GstBusSource;
|
|
|
|
static gboolean
|
|
gst_bus_source_prepare (GSource * source, gint * timeout)
|
|
{
|
|
*timeout = -1;
|
|
return FALSE;
|
|
}
|
|
|
|
static gboolean
|
|
gst_bus_source_check (GSource * source)
|
|
{
|
|
GstBusSource *bsrc = (GstBusSource *) source;
|
|
|
|
return bsrc->bus->priv->pollfd.revents & (G_IO_IN | G_IO_HUP | G_IO_ERR);
|
|
}
|
|
|
|
static gboolean
|
|
gst_bus_source_dispatch (GSource * source, GSourceFunc callback,
|
|
gpointer user_data)
|
|
{
|
|
GstBusFunc handler = (GstBusFunc) callback;
|
|
GstBusSource *bsource = (GstBusSource *) source;
|
|
GstMessage *message;
|
|
gboolean keep;
|
|
GstBus *bus;
|
|
|
|
g_return_val_if_fail (bsource != NULL, FALSE);
|
|
|
|
bus = bsource->bus;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
|
|
|
|
message = gst_bus_pop (bus);
|
|
|
|
/* The message queue might be empty if some other thread or callback set
|
|
* the bus to flushing between check/prepare and dispatch */
|
|
if (G_UNLIKELY (message == NULL))
|
|
return TRUE;
|
|
|
|
if (!handler)
|
|
goto no_handler;
|
|
|
|
GST_DEBUG_OBJECT (bus, "source %p calling dispatch with %" GST_PTR_FORMAT,
|
|
source, message);
|
|
|
|
keep = handler (bus, message, user_data);
|
|
gst_message_unref (message);
|
|
|
|
GST_DEBUG_OBJECT (bus, "source %p handler returns %d", source, keep);
|
|
|
|
return keep;
|
|
|
|
no_handler:
|
|
{
|
|
g_warning ("GstBus watch dispatched without callback\n"
|
|
"You must call g_source_set_callback().");
|
|
gst_message_unref (message);
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
static void
|
|
gst_bus_source_finalize (GSource * source)
|
|
{
|
|
GstBusSource *bsource = (GstBusSource *) source;
|
|
GstBus *bus;
|
|
|
|
bus = bsource->bus;
|
|
|
|
GST_DEBUG_OBJECT (bus, "finalize source %p", source);
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
if (bus->priv->signal_watch == source)
|
|
bus->priv->signal_watch = NULL;
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
gst_object_unref (bsource->bus);
|
|
bsource->bus = NULL;
|
|
}
|
|
|
|
static GSourceFuncs gst_bus_source_funcs = {
|
|
gst_bus_source_prepare,
|
|
gst_bus_source_check,
|
|
gst_bus_source_dispatch,
|
|
gst_bus_source_finalize
|
|
};
|
|
|
|
/**
|
|
* gst_bus_create_watch:
|
|
* @bus: a #GstBus to create the watch for
|
|
*
|
|
* Create watch for this bus. The GSource will be dispatched whenever
|
|
* a message is on the bus. After the GSource is dispatched, the
|
|
* message is popped off the bus and unreffed.
|
|
*
|
|
* Returns: (transfer full) (nullable): a #GSource that can be added to a mainloop.
|
|
*/
|
|
GSource *
|
|
gst_bus_create_watch (GstBus * bus)
|
|
{
|
|
GstBusSource *source;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
g_return_val_if_fail (bus->priv->poll != NULL, NULL);
|
|
|
|
source = (GstBusSource *) g_source_new (&gst_bus_source_funcs,
|
|
sizeof (GstBusSource));
|
|
|
|
g_source_set_name ((GSource *) source, "GStreamer message bus watch");
|
|
|
|
source->bus = gst_object_ref (bus);
|
|
g_source_add_poll ((GSource *) source, &bus->priv->pollfd);
|
|
|
|
return (GSource *) source;
|
|
}
|
|
|
|
/* must be called with the bus OBJECT LOCK */
|
|
static guint
|
|
gst_bus_add_watch_full_unlocked (GstBus * bus, gint priority,
|
|
GstBusFunc func, gpointer user_data, GDestroyNotify notify)
|
|
{
|
|
GMainContext *ctx;
|
|
guint id;
|
|
GSource *source;
|
|
|
|
if (bus->priv->signal_watch) {
|
|
GST_ERROR_OBJECT (bus,
|
|
"Tried to add new watch while one was already there");
|
|
return 0;
|
|
}
|
|
|
|
source = gst_bus_create_watch (bus);
|
|
if (!source) {
|
|
g_critical ("Creating bus watch failed");
|
|
return 0;
|
|
}
|
|
|
|
if (priority != G_PRIORITY_DEFAULT)
|
|
g_source_set_priority (source, priority);
|
|
|
|
g_source_set_callback (source, (GSourceFunc) func, user_data, notify);
|
|
|
|
ctx = g_main_context_get_thread_default ();
|
|
id = g_source_attach (source, ctx);
|
|
g_source_unref (source);
|
|
|
|
if (id) {
|
|
bus->priv->signal_watch = source;
|
|
}
|
|
|
|
GST_DEBUG_OBJECT (bus, "New source %p with id %u", source, id);
|
|
return id;
|
|
}
|
|
|
|
/**
|
|
* gst_bus_add_watch_full: (rename-to gst_bus_add_watch)
|
|
* @bus: a #GstBus to create the watch for.
|
|
* @priority: The priority of the watch.
|
|
* @func: A function to call when a message is received.
|
|
* @user_data: user data passed to @func.
|
|
* @notify: the function to call when the source is removed.
|
|
*
|
|
* Adds a bus watch to the default main context with the given @priority (e.g.
|
|
* %G_PRIORITY_DEFAULT). It is also possible to use a non-default main
|
|
* context set up using g_main_context_push_thread_default() (before
|
|
* one had to create a bus watch source and attach it to the desired main
|
|
* context 'manually').
|
|
*
|
|
* This function is used to receive asynchronous messages in the main loop.
|
|
* There can only be a single bus watch per bus, you must remove it before you
|
|
* can set a new one.
|
|
*
|
|
* The bus watch will only work if a GLib main loop is being run.
|
|
*
|
|
* When @func is called, the message belongs to the caller; if you want to
|
|
* keep a copy of it, call gst_message_ref() before leaving @func.
|
|
*
|
|
* The watch can be removed using gst_bus_remove_watch() or by returning %FALSE
|
|
* from @func. If the watch was added to the default main context it is also
|
|
* possible to remove the watch using g_source_remove().
|
|
*
|
|
* The bus watch will take its own reference to the @bus, so it is safe to unref
|
|
* @bus using gst_object_unref() after setting the bus watch.
|
|
*
|
|
* MT safe.
|
|
*
|
|
* Returns: The event source id or 0 if @bus already got an event source.
|
|
*/
|
|
guint
|
|
gst_bus_add_watch_full (GstBus * bus, gint priority,
|
|
GstBusFunc func, gpointer user_data, GDestroyNotify notify)
|
|
{
|
|
guint id;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), 0);
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
id = gst_bus_add_watch_full_unlocked (bus, priority, func, user_data, notify);
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
return id;
|
|
}
|
|
|
|
/**
|
|
* gst_bus_add_watch: (skip)
|
|
* @bus: a #GstBus to create the watch for
|
|
* @func: A function to call when a message is received.
|
|
* @user_data: user data passed to @func.
|
|
*
|
|
* Adds a bus watch to the default main context with the default priority
|
|
* (%G_PRIORITY_DEFAULT). It is also possible to use a non-default main
|
|
* context set up using g_main_context_push_thread_default() (before
|
|
* one had to create a bus watch source and attach it to the desired main
|
|
* context 'manually').
|
|
*
|
|
* This function is used to receive asynchronous messages in the main loop.
|
|
* There can only be a single bus watch per bus, you must remove it before you
|
|
* can set a new one.
|
|
*
|
|
* The bus watch will only work if a GLib main loop is being run.
|
|
*
|
|
* The watch can be removed using gst_bus_remove_watch() or by returning %FALSE
|
|
* from @func. If the watch was added to the default main context it is also
|
|
* possible to remove the watch using g_source_remove().
|
|
*
|
|
* The bus watch will take its own reference to the @bus, so it is safe to unref
|
|
* @bus using gst_object_unref() after setting the bus watch.
|
|
*
|
|
* MT safe.
|
|
*
|
|
* Returns: The event source id or 0 if @bus already got an event source.
|
|
*/
|
|
guint
|
|
gst_bus_add_watch (GstBus * bus, GstBusFunc func, gpointer user_data)
|
|
{
|
|
return gst_bus_add_watch_full (bus, G_PRIORITY_DEFAULT, func,
|
|
user_data, NULL);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_remove_watch:
|
|
* @bus: a #GstBus to remove the watch from.
|
|
*
|
|
* Removes an installed bus watch from @bus.
|
|
*
|
|
* Returns: %TRUE on success or %FALSE if @bus has no event source.
|
|
*
|
|
* Since: 1.6
|
|
*
|
|
*/
|
|
gboolean
|
|
gst_bus_remove_watch (GstBus * bus)
|
|
{
|
|
GSource *source;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
|
|
if (bus->priv->signal_watch == NULL) {
|
|
GST_ERROR_OBJECT (bus, "no bus watch was present");
|
|
goto error;
|
|
}
|
|
|
|
if (bus->priv->num_signal_watchers > 0) {
|
|
GST_ERROR_OBJECT (bus,
|
|
"trying to remove signal watch with gst_bus_remove_watch()");
|
|
goto error;
|
|
}
|
|
|
|
source =
|
|
bus->priv->signal_watch ? g_source_ref (bus->priv->signal_watch) : NULL;
|
|
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
if (source) {
|
|
g_source_destroy (source);
|
|
g_source_unref (source);
|
|
}
|
|
|
|
return TRUE;
|
|
|
|
error:
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
typedef struct
|
|
{
|
|
GMainLoop *loop;
|
|
guint timeout_id;
|
|
gboolean source_running;
|
|
GstMessageType events;
|
|
GstMessage *message;
|
|
} GstBusPollData;
|
|
|
|
static void
|
|
poll_func (GstBus * bus, GstMessage * message, GstBusPollData * poll_data)
|
|
{
|
|
GstMessageType type;
|
|
|
|
if (!g_main_loop_is_running (poll_data->loop)) {
|
|
GST_DEBUG ("mainloop %p not running", poll_data->loop);
|
|
return;
|
|
}
|
|
|
|
type = GST_MESSAGE_TYPE (message);
|
|
|
|
if (type & poll_data->events) {
|
|
g_assert (poll_data->message == NULL);
|
|
/* keep ref to message */
|
|
poll_data->message = gst_message_ref (message);
|
|
GST_DEBUG ("mainloop %p quit", poll_data->loop);
|
|
g_main_loop_quit (poll_data->loop);
|
|
} else {
|
|
GST_DEBUG ("type %08x does not match %08x", type, poll_data->events);
|
|
}
|
|
}
|
|
|
|
static gboolean
|
|
poll_timeout (GstBusPollData * poll_data)
|
|
{
|
|
GST_DEBUG ("mainloop %p quit", poll_data->loop);
|
|
g_main_loop_quit (poll_data->loop);
|
|
|
|
/* we don't remove the GSource as this would free our poll_data,
|
|
* which we still need */
|
|
return TRUE;
|
|
}
|
|
|
|
static void
|
|
poll_destroy (GstBusPollData * poll_data, gpointer unused)
|
|
{
|
|
poll_data->source_running = FALSE;
|
|
if (!poll_data->timeout_id) {
|
|
g_main_loop_unref (poll_data->loop);
|
|
g_slice_free (GstBusPollData, poll_data);
|
|
}
|
|
}
|
|
|
|
static void
|
|
poll_destroy_timeout (GstBusPollData * poll_data)
|
|
{
|
|
poll_data->timeout_id = 0;
|
|
if (!poll_data->source_running) {
|
|
g_main_loop_unref (poll_data->loop);
|
|
g_slice_free (GstBusPollData, poll_data);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* gst_bus_poll:
|
|
* @bus: a #GstBus
|
|
* @events: a mask of #GstMessageType, representing the set of message types to
|
|
* poll for (note special handling of extended message types below)
|
|
* @timeout: the poll timeout, as a #GstClockTime, or #GST_CLOCK_TIME_NONE to poll
|
|
* indefinitely.
|
|
*
|
|
* Poll the bus for messages. Will block while waiting for messages to come.
|
|
* You can specify a maximum time to poll with the @timeout parameter. If
|
|
* @timeout is negative, this function will block indefinitely.
|
|
*
|
|
* All messages not in @events will be popped off the bus and will be ignored.
|
|
* It is not possible to use message enums beyond #GST_MESSAGE_EXTENDED in the
|
|
* @events mask
|
|
*
|
|
* Because poll is implemented using the "message" signal enabled by
|
|
* gst_bus_add_signal_watch(), calling gst_bus_poll() will cause the "message"
|
|
* signal to be emitted for every message that poll sees. Thus a "message"
|
|
* signal handler will see the same messages that this function sees -- neither
|
|
* will steal messages from the other.
|
|
*
|
|
* This function will run a main loop from the default main context when
|
|
* polling.
|
|
*
|
|
* You should never use this function, since it is pure evil. This is
|
|
* especially true for GUI applications based on Gtk+ or Qt, but also for any
|
|
* other non-trivial application that uses the GLib main loop. As this function
|
|
* runs a GLib main loop, any callback attached to the default GLib main
|
|
* context may be invoked. This could be timeouts, GUI events, I/O events etc.;
|
|
* even if gst_bus_poll() is called with a 0 timeout. Any of these callbacks
|
|
* may do things you do not expect, e.g. destroy the main application window or
|
|
* some other resource; change other application state; display a dialog and
|
|
* run another main loop until the user clicks it away. In short, using this
|
|
* function may add a lot of complexity to your code through unexpected
|
|
* re-entrancy and unexpected changes to your application's state.
|
|
*
|
|
* For 0 timeouts use gst_bus_pop_filtered() instead of this function; for
|
|
* other short timeouts use gst_bus_timed_pop_filtered(); everything else is
|
|
* better handled by setting up an asynchronous bus watch and doing things
|
|
* from there.
|
|
*
|
|
* Returns: (transfer full) (nullable): the message that was received,
|
|
* or %NULL if the poll timed out. The message is taken from the
|
|
* bus and needs to be unreffed with gst_message_unref() after
|
|
* usage.
|
|
*/
|
|
GstMessage *
|
|
gst_bus_poll (GstBus * bus, GstMessageType events, GstClockTime timeout)
|
|
{
|
|
GstBusPollData *poll_data;
|
|
GstMessage *ret;
|
|
gulong id;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
|
|
|
|
poll_data = g_slice_new (GstBusPollData);
|
|
poll_data->source_running = TRUE;
|
|
poll_data->loop = g_main_loop_new (NULL, FALSE);
|
|
poll_data->events = events;
|
|
poll_data->message = NULL;
|
|
|
|
if (timeout != GST_CLOCK_TIME_NONE)
|
|
poll_data->timeout_id = g_timeout_add_full (G_PRIORITY_DEFAULT_IDLE,
|
|
timeout / GST_MSECOND, (GSourceFunc) poll_timeout, poll_data,
|
|
(GDestroyNotify) poll_destroy_timeout);
|
|
else
|
|
poll_data->timeout_id = 0;
|
|
|
|
id = g_signal_connect_data (bus, "message", G_CALLBACK (poll_func), poll_data,
|
|
(GClosureNotify) poll_destroy, 0);
|
|
|
|
/* these can be nested, so it's ok */
|
|
gst_bus_add_signal_watch (bus);
|
|
|
|
GST_DEBUG ("running mainloop %p", poll_data->loop);
|
|
g_main_loop_run (poll_data->loop);
|
|
GST_DEBUG ("mainloop stopped %p", poll_data->loop);
|
|
|
|
gst_bus_remove_signal_watch (bus);
|
|
|
|
/* holds a ref */
|
|
ret = poll_data->message;
|
|
|
|
if (poll_data->timeout_id)
|
|
g_source_remove (poll_data->timeout_id);
|
|
|
|
/* poll_data will be freed now */
|
|
g_signal_handler_disconnect (bus, id);
|
|
|
|
GST_DEBUG_OBJECT (bus, "finished poll with message %p", ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* gst_bus_async_signal_func:
|
|
* @bus: a #GstBus
|
|
* @message: the #GstMessage received
|
|
* @data: user data
|
|
*
|
|
* A helper #GstBusFunc that can be used to convert all asynchronous messages
|
|
* into signals.
|
|
*
|
|
* Returns: %TRUE
|
|
*/
|
|
gboolean
|
|
gst_bus_async_signal_func (GstBus * bus, GstMessage * message, gpointer data)
|
|
{
|
|
GQuark detail = 0;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), TRUE);
|
|
g_return_val_if_fail (message != NULL, TRUE);
|
|
|
|
detail = gst_message_type_to_quark (GST_MESSAGE_TYPE (message));
|
|
|
|
g_signal_emit (bus, gst_bus_signals[ASYNC_MESSAGE], detail, message);
|
|
|
|
/* we never remove this source based on signal emission return values */
|
|
return TRUE;
|
|
}
|
|
|
|
/**
|
|
* gst_bus_sync_signal_handler:
|
|
* @bus: a #GstBus
|
|
* @message: the #GstMessage received
|
|
* @data: user data
|
|
*
|
|
* A helper GstBusSyncHandler that can be used to convert all synchronous
|
|
* messages into signals.
|
|
*
|
|
* Returns: GST_BUS_PASS
|
|
*/
|
|
GstBusSyncReply
|
|
gst_bus_sync_signal_handler (GstBus * bus, GstMessage * message, gpointer data)
|
|
{
|
|
GQuark detail = 0;
|
|
|
|
g_return_val_if_fail (GST_IS_BUS (bus), GST_BUS_DROP);
|
|
g_return_val_if_fail (message != NULL, GST_BUS_DROP);
|
|
|
|
detail = gst_message_type_to_quark (GST_MESSAGE_TYPE (message));
|
|
|
|
g_signal_emit (bus, gst_bus_signals[SYNC_MESSAGE], detail, message);
|
|
|
|
return GST_BUS_PASS;
|
|
}
|
|
|
|
/**
|
|
* gst_bus_enable_sync_message_emission:
|
|
* @bus: a #GstBus on which you want to receive the "sync-message" signal
|
|
*
|
|
* Instructs GStreamer to emit the "sync-message" signal after running the bus's
|
|
* sync handler. This function is here so that code can ensure that they can
|
|
* synchronously receive messages without having to affect what the bin's sync
|
|
* handler is.
|
|
*
|
|
* This function may be called multiple times. To clean up, the caller is
|
|
* responsible for calling gst_bus_disable_sync_message_emission() as many times
|
|
* as this function is called.
|
|
*
|
|
* While this function looks similar to gst_bus_add_signal_watch(), it is not
|
|
* exactly the same -- this function enables <emphasis>synchronous</emphasis> emission of
|
|
* signals when messages arrive; gst_bus_add_signal_watch() adds an idle callback
|
|
* to pop messages off the bus <emphasis>asynchronously</emphasis>. The sync-message signal
|
|
* comes from the thread of whatever object posted the message; the "message"
|
|
* signal is marshalled to the main thread via the main loop.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
void
|
|
gst_bus_enable_sync_message_emission (GstBus * bus)
|
|
{
|
|
g_return_if_fail (GST_IS_BUS (bus));
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
bus->priv->num_sync_message_emitters++;
|
|
GST_OBJECT_UNLOCK (bus);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_disable_sync_message_emission:
|
|
* @bus: a #GstBus on which you previously called
|
|
* gst_bus_enable_sync_message_emission()
|
|
*
|
|
* Instructs GStreamer to stop emitting the "sync-message" signal for this bus.
|
|
* See gst_bus_enable_sync_message_emission() for more information.
|
|
*
|
|
* In the event that multiple pieces of code have called
|
|
* gst_bus_enable_sync_message_emission(), the sync-message emissions will only
|
|
* be stopped after all calls to gst_bus_enable_sync_message_emission() were
|
|
* "cancelled" by calling this function. In this way the semantics are exactly
|
|
* the same as gst_object_ref() that which calls enable should also call
|
|
* disable.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
void
|
|
gst_bus_disable_sync_message_emission (GstBus * bus)
|
|
{
|
|
g_return_if_fail (GST_IS_BUS (bus));
|
|
g_return_if_fail (bus->priv->num_sync_message_emitters > 0);
|
|
|
|
GST_OBJECT_LOCK (bus);
|
|
bus->priv->num_sync_message_emitters--;
|
|
GST_OBJECT_UNLOCK (bus);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_add_signal_watch_full:
|
|
* @bus: a #GstBus on which you want to receive the "message" signal
|
|
* @priority: The priority of the watch.
|
|
*
|
|
* Adds a bus signal watch to the default main context with the given @priority
|
|
* (e.g. %G_PRIORITY_DEFAULT). It is also possible to use a non-default main
|
|
* context set up using g_main_context_push_thread_default()
|
|
* (before one had to create a bus watch source and attach it to the desired
|
|
* main context 'manually').
|
|
*
|
|
* After calling this statement, the bus will emit the "message" signal for each
|
|
* message posted on the bus when the main loop is running.
|
|
*
|
|
* This function may be called multiple times. To clean up, the caller is
|
|
* responsible for calling gst_bus_remove_signal_watch() as many times as this
|
|
* function is called.
|
|
*
|
|
* There can only be a single bus watch per bus, you must remove any signal
|
|
* watch before you can set another type of watch.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
void
|
|
gst_bus_add_signal_watch_full (GstBus * bus, gint priority)
|
|
{
|
|
g_return_if_fail (GST_IS_BUS (bus));
|
|
|
|
/* I know the callees don't take this lock, so go ahead and abuse it */
|
|
GST_OBJECT_LOCK (bus);
|
|
|
|
if (bus->priv->num_signal_watchers > 0)
|
|
goto done;
|
|
|
|
/* this should not fail because the counter above takes care of it */
|
|
g_assert (!bus->priv->signal_watch);
|
|
|
|
gst_bus_add_watch_full_unlocked (bus, priority, gst_bus_async_signal_func,
|
|
NULL, NULL);
|
|
|
|
if (G_UNLIKELY (!bus->priv->signal_watch))
|
|
goto add_failed;
|
|
|
|
done:
|
|
|
|
bus->priv->num_signal_watchers++;
|
|
|
|
GST_OBJECT_UNLOCK (bus);
|
|
return;
|
|
|
|
/* ERRORS */
|
|
add_failed:
|
|
{
|
|
g_critical ("Could not add signal watch to bus %s", GST_OBJECT_NAME (bus));
|
|
GST_OBJECT_UNLOCK (bus);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* gst_bus_add_signal_watch:
|
|
* @bus: a #GstBus on which you want to receive the "message" signal
|
|
*
|
|
* Adds a bus signal watch to the default main context with the default priority
|
|
* (%G_PRIORITY_DEFAULT). It is also possible to use a non-default
|
|
* main context set up using g_main_context_push_thread_default() (before
|
|
* one had to create a bus watch source and attach it to the desired main
|
|
* context 'manually').
|
|
*
|
|
* After calling this statement, the bus will emit the "message" signal for each
|
|
* message posted on the bus.
|
|
*
|
|
* This function may be called multiple times. To clean up, the caller is
|
|
* responsible for calling gst_bus_remove_signal_watch() as many times as this
|
|
* function is called.
|
|
*
|
|
* MT safe.
|
|
*/
|
|
void
|
|
gst_bus_add_signal_watch (GstBus * bus)
|
|
{
|
|
gst_bus_add_signal_watch_full (bus, G_PRIORITY_DEFAULT);
|
|
}
|
|
|
|
/**
|
|
* gst_bus_remove_signal_watch:
|
|
* @bus: a #GstBus you previously added a signal watch to
|
|
*
|
|
* Removes a signal watch previously added with gst_bus_add_signal_watch().
|
|
*
|
|
* MT safe.
|
|
*/
|
|
void
|
|
gst_bus_remove_signal_watch (GstBus * bus)
|
|
{
|
|
GSource *source = NULL;
|
|
|
|
g_return_if_fail (GST_IS_BUS (bus));
|
|
|
|
/* I know the callees don't take this lock, so go ahead and abuse it */
|
|
GST_OBJECT_LOCK (bus);
|
|
|
|
if (bus->priv->num_signal_watchers == 0)
|
|
goto error;
|
|
|
|
bus->priv->num_signal_watchers--;
|
|
|
|
if (bus->priv->num_signal_watchers > 0)
|
|
goto done;
|
|
|
|
GST_DEBUG_OBJECT (bus, "removing signal watch %u",
|
|
g_source_get_id (bus->priv->signal_watch));
|
|
|
|
source =
|
|
bus->priv->signal_watch ? g_source_ref (bus->priv->signal_watch) : NULL;
|
|
|
|
done:
|
|
GST_OBJECT_UNLOCK (bus);
|
|
|
|
if (source) {
|
|
g_source_destroy (source);
|
|
g_source_unref (source);
|
|
}
|
|
|
|
return;
|
|
|
|
/* ERRORS */
|
|
error:
|
|
{
|
|
g_critical ("Bus %s has no signal watches attached", GST_OBJECT_NAME (bus));
|
|
GST_OBJECT_UNLOCK (bus);
|
|
return;
|
|
}
|
|
}
|