/* GStreamer
* Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
*
* gstbus.c: GstBus subsystem
*
* 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.
*/
/**
* SECTION:gstbus
* @short_description: Asynchronous message bus subsystem
* @see_also: #GstMessage, #GstElement
*
* The #GstBus is an object responsible for delivering #GstMessages in
* a first-in first-out way from the streaming threads to the application.
*
* Since the application typically only wants to deal with delivery of these
* messages from one thread, the GstBus will marshall the messages between
* different threads. This is important since the actual streaming of media
* is done in another thread than the application.
*
* The GstBus provides support for #GSource based notifications. This makes it
* possible to handle the delivery in the glib mainloop.
*
* The #GSource callback function gst_bus_async_signal_func() can be used to
* convert all bus messages into signal emissions.
*
* A message is posted on the bus with the gst_bus_post() method. With the
* gst_bus_peek() and gst_bus_pop() methods one can look at or retrieve a
* previously posted message.
*
* The bus can be polled with the gst_bus_poll() method. This methods blocks
* up to the specified timeout value until one of the specified messages types
* is posted on the bus. The application can then _pop() the messages from the
* bus to handle them.
* Alternatively the application can register an asynchronous bus function
* using gst_bus_add_watch_full() or gst_bus_add_watch(). This function will
* install a #GSource in the default glib main loop and will deliver messages
* a short while after they have been posted. Note that the main loop should
* be running for the asynchronous callbacks.
*
* It is also possible to get messages from the bus without any thread
* marshalling with the gst_bus_set_sync_handler() method. This makes it
* possible to react to a message in the same thread that posted the
* message on the bus. This should only be used if the application is able
* to deal with messages from different threads.
*
* Every #GstPipeline has one bus.
*
* Note that a #GstPipeline will set its bus into flushing state when changing
* from READY to NULL state.
*
* Last reviewed on 2006-03-12 (0.10.5)
*/
#include "gst_private.h"
#include <errno.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <sys/types.h>
#include "gstinfo.h"
#include "gstbus.h"
#ifdef __SYMBIAN32__
#include <glib_global.h>
#endif
#define GST_CAT_DEFAULT GST_CAT_BUS
/* bus signals */
enum
{
SYNC_MESSAGE,
ASYNC_MESSAGE,
/* add more above */
LAST_SIGNAL
};
static void gst_bus_class_init (GstBusClass * klass);
static void gst_bus_init (GstBus * bus);
static void gst_bus_dispose (GObject * object);
static void gst_bus_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_bus_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static GstObjectClass *parent_class = NULL;
static guint gst_bus_signals[LAST_SIGNAL] = { 0 };
/* the context we wakeup when we posted a message on the bus */
static GMainContext *main_context;
struct _GstBusPrivate
{
guint num_sync_message_emitters;
GCond *queue_cond;
};
#ifdef __SYMBIAN32__
EXPORT_C
#endif
GType
gst_bus_get_type (void)
{
static GType bus_type = 0;
if (G_UNLIKELY (bus_type == 0)) {
static const GTypeInfo bus_info = {
sizeof (GstBusClass),
NULL,
NULL,
(GClassInitFunc) gst_bus_class_init,
NULL,
NULL,
sizeof (GstBus),
0,
(GInstanceInitFunc) gst_bus_init,
NULL
};
bus_type = g_type_register_static (GST_TYPE_OBJECT, "GstBus", &bus_info, 0);
}
return bus_type;
}
/* fixme: do something about this */
static void
marshal_VOID__MINIOBJECT (GClosure * closure, GValue * return_value,
guint n_param_values, const GValue * param_values, gpointer invocation_hint,
gpointer marshal_data)
{
typedef void (*marshalfunc_VOID__MINIOBJECT) (gpointer obj, gpointer arg1,
gpointer data2);
register marshalfunc_VOID__MINIOBJECT callback;
register GCClosure *cc = (GCClosure *) closure;
register gpointer data1, data2;
g_return_if_fail (n_param_values == 2);
if (G_CCLOSURE_SWAP_DATA (closure)) {
data1 = closure->data;
data2 = g_value_peek_pointer (param_values + 0);
} else {
data1 = g_value_peek_pointer (param_values + 0);
data2 = closure->data;
}
callback =
(marshalfunc_VOID__MINIOBJECT) (marshal_data ? marshal_data : cc->
callback);
callback (data1, gst_value_get_mini_object (param_values + 1), data2);
}
static void
gst_bus_class_init (GstBusClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
parent_class = g_type_class_peek_parent (klass);
if (!g_thread_supported ())
g_thread_init (NULL);
gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_bus_dispose);
gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_bus_set_property);
gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_bus_get_property);
/**
* GstBus::sync-message:
* @bus: the object which received the signal
* @message: the message that has been posted synchronously
*
* A message has been posted on the bus. This signal is emitted from the
* thread that posted the message so one has to be careful with locking.
*
* This signal will not be emitted by default, you have to set up
* gst_bus_sync_signal_handler() as a sync handler if you want this
* signal to be emitted when a message is posted on the bus, like this:
* <programlisting>
* gst_bus_set_sync_handler (bus, gst_bus_sync_signal_handler, yourdata);
* </programlisting>
*/
gst_bus_signals[SYNC_MESSAGE] =
g_signal_new ("sync-message", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
G_STRUCT_OFFSET (GstBusClass, sync_message), NULL, NULL,
marshal_VOID__MINIOBJECT, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
/**
* GstBus::message:
* @bus: the object which received the signal
* @message: the message that has been posted asynchronously
*
* A message has been posted on the bus. This signal is emitted from a
* GSource added to the mainloop. this signal will only be emitted when
* there is a mainloop running.
*/
gst_bus_signals[ASYNC_MESSAGE] =
g_signal_new ("message", G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
G_STRUCT_OFFSET (GstBusClass, message), NULL, NULL,
marshal_VOID__MINIOBJECT, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
main_context = g_main_context_default ();
g_type_class_add_private (klass, sizeof (GstBusPrivate));
}
static void
gst_bus_init (GstBus * bus)
{
bus->queue = g_queue_new ();
bus->queue_lock = g_mutex_new ();
bus->priv = G_TYPE_INSTANCE_GET_PRIVATE (bus, GST_TYPE_BUS, GstBusPrivate);
bus->priv->queue_cond = g_cond_new ();
GST_DEBUG_OBJECT (bus, "created");
}
static void
gst_bus_dispose (GObject * object)
{
GstBus *bus;
bus = GST_BUS (object);
if (bus->queue) {
GstMessage *message;
g_mutex_lock (bus->queue_lock);
do {
message = g_queue_pop_head (bus->queue);
if (message)
gst_message_unref (message);
} while (message != NULL);
g_queue_free (bus->queue);
bus->queue = NULL;
g_mutex_unlock (bus->queue_lock);
g_mutex_free (bus->queue_lock);
bus->queue_lock = NULL;
g_cond_free (bus->priv->queue_cond);
bus->priv->queue_cond = NULL;
}
G_OBJECT_CLASS (parent_class)->dispose (object);
}
static void
gst_bus_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstBus *bus;
bus = GST_BUS (object);
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_bus_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstBus *bus;
bus = GST_BUS (object);
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
/**
* gst_bus_new:
*
* Creates a new #GstBus instance.
*
* Returns: a new #GstBus instance
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
GstBus *
gst_bus_new (void)
{
GstBus *result;
result = g_object_new (gst_bus_get_type (), NULL);
GST_DEBUG_OBJECT (result, "created new bus");
return result;
}
/**
* gst_bus_post:
* @bus: a #GstBus to post on
* @message: The #GstMessage to post
*
* Post a message on the given bus. Ownership of the message
* is taken by the bus.
*
* Returns: TRUE if the message could be posted, FALSE if the bus is flushing.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
gboolean
gst_bus_post (GstBus * bus, GstMessage * message)
{
GstBusSyncReply reply = GST_BUS_PASS;
GstBusSyncHandler handler;
gboolean emit_sync_message;
gpointer handler_data;
g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
g_return_val_if_fail (GST_IS_MESSAGE (message), FALSE);
GST_DEBUG_OBJECT (bus, "[msg %p] posting on bus, type %s, %" GST_PTR_FORMAT
" from source %" GST_PTR_FORMAT,
message, GST_MESSAGE_TYPE_NAME (message), message->structure,
message->src);
GST_OBJECT_LOCK (bus);
/* check if the bus is flushing */
if (GST_OBJECT_FLAG_IS_SET (bus, GST_BUS_FLUSHING))
goto is_flushing;
handler = bus->sync_handler;
handler_data = bus->sync_handler_data;
emit_sync_message = bus->priv->num_sync_message_emitters > 0;
GST_OBJECT_UNLOCK (bus);
/* first call the sync handler if it is installed */
if (handler)
reply = handler (bus, message, handler_data);
/* emit sync-message if requested to do so via
gst_bus_enable_sync_message_emission. terrible but effective */
if (emit_sync_message && reply != GST_BUS_DROP
&& handler != gst_bus_sync_signal_handler)
gst_bus_sync_signal_handler (bus, message, NULL);
/* now see what we should do with the message */
switch (reply) {
case GST_BUS_DROP:
/* drop the message */
GST_DEBUG_OBJECT (bus, "[msg %p] dropped", message);
break;
case GST_BUS_PASS:
/* pass the message to the async queue, refcount passed in the queue */
GST_DEBUG_OBJECT (bus, "[msg %p] pushing on async queue", message);
g_mutex_lock (bus->queue_lock);
g_queue_push_tail (bus->queue, message);
g_cond_broadcast (bus->priv->queue_cond);
g_mutex_unlock (bus->queue_lock);
GST_DEBUG_OBJECT (bus, "[msg %p] pushed on async queue", message);
/* FIXME cannot assume sources are only in the default context */
g_main_context_wakeup (main_context);
break;
case GST_BUS_ASYNC:
{
/* async delivery, we need a mutex and a cond to block
* on */
GMutex *lock = g_mutex_new ();
GCond *cond = g_cond_new ();
GST_MESSAGE_COND (message) = cond;
GST_MESSAGE_GET_LOCK (message) = lock;
GST_DEBUG_OBJECT (bus, "[msg %p] waiting for async delivery", message);
/* now we lock the message mutex, send the message to the async
* queue. When the message is handled by the app and destroyed,
* the cond will be signalled and we can continue */
g_mutex_lock (lock);
g_mutex_lock (bus->queue_lock);
g_queue_push_tail (bus->queue, message);
g_cond_broadcast (bus->priv->queue_cond);
g_mutex_unlock (bus->queue_lock);
/* FIXME cannot assume sources are only in the default context */
g_main_context_wakeup (main_context);
/* now block till the message is freed */
g_cond_wait (cond, lock);
g_mutex_unlock (lock);
GST_DEBUG_OBJECT (bus, "[msg %p] delivered asynchronously", message);
g_mutex_free (lock);
g_cond_free (cond);
break;
}
default:
g_warning ("invalid return from bus sync handler");
break;
}
return TRUE;
/* ERRORS */
is_flushing:
{
GST_DEBUG_OBJECT (bus, "bus is flushing");
gst_message_unref (message);
GST_OBJECT_UNLOCK (bus);
return FALSE;
}
}
/**
* gst_bus_have_pending:
* @bus: a #GstBus to check
*
* Check if there are pending messages on the bus that
* should be handled.
*
* Returns: TRUE if there are messages on the bus to be handled, FALSE
* otherwise.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
gboolean
gst_bus_have_pending (GstBus * bus)
{
gboolean result;
g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
g_mutex_lock (bus->queue_lock);
/* see if there is a message on the bus */
result = !g_queue_is_empty (bus->queue);
g_mutex_unlock (bus->queue_lock);
return result;
}
/**
* gst_bus_set_flushing:
* @bus: a #GstBus
* @flushing: whether or not to flush the bus
*
* If @flushing, flush out and unref any messages queued in the bus. Releases
* references to the message origin objects. Will flush future messages until
* gst_bus_set_flushing() sets @flushing to #FALSE.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
void
gst_bus_set_flushing (GstBus * bus, gboolean flushing)
{
GstMessage *message;
GST_OBJECT_LOCK (bus);
if (flushing) {
GST_OBJECT_FLAG_SET (bus, GST_BUS_FLUSHING);
GST_DEBUG_OBJECT (bus, "set bus flushing");
while ((message = gst_bus_pop (bus)))
gst_message_unref (message);
} else {
GST_DEBUG_OBJECT (bus, "unset bus flushing");
GST_OBJECT_FLAG_UNSET (bus, GST_BUS_FLUSHING);
}
GST_OBJECT_UNLOCK (bus);
}
/**
* gst_bus_timed_pop_filtered:
* @bus: a #GstBus to pop from
* @timeout: a timeout in nanoseconds, or GST_CLOCK_TIME_NONE to wait forever
* @types: message types to take into account, GST_MESSAGE_ANY for any type
*
* Get a message from the bus whose type matches the message type mask @types,
* waiting up to the specified timeout (and discarding any messages that do not
* match the mask provided).
*
* If @timeout is 0, this function behaves like gst_bus_pop_filtered(). If
* @timeout is #GST_CLOCK_TIME_NONE, this function will block forever until a
* matching message was posted on the bus.
*
* Returns: a #GstMessage matching the filter in @types, or NULL if no matching
* message was found on the bus until the timeout expired.
* The message is taken from the bus and needs to be unreffed with
* gst_message_unref() after usage.
*
* MT safe.
*
* Since: 0.10.15
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
GstMessage *
gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout,
GstMessageType types)
{
GstMessage *message;
GTimeVal *timeval, abstimeout;
gboolean first_round = TRUE;
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
g_return_val_if_fail (types != 0, NULL);
g_mutex_lock (bus->queue_lock);
while (TRUE) {
GST_LOG_OBJECT (bus, "have %d messages", g_queue_get_length (bus->queue));
while ((message = g_queue_pop_head (bus->queue))) {
GST_DEBUG_OBJECT (bus, "got message %p, %s, type mask is %u",
message, GST_MESSAGE_TYPE_NAME (message), (guint) types);
if ((GST_MESSAGE_TYPE (message) & types) != 0) {
/* exit the loop, we have a message */
goto beach;
} else {
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;
if (timeout == GST_CLOCK_TIME_NONE) {
/* wait forever */
timeval = NULL;
} else if (first_round) {
glong add = timeout / 1000;
if (add == 0)
/* no need to wait */
break;
/* make timeout absolute */
g_get_current_time (&abstimeout);
g_time_val_add (&abstimeout, add);
timeval = &abstimeout;
first_round = FALSE;
GST_DEBUG_OBJECT (bus, "blocking for message, timeout %ld", add);
} else {
/* calculated the absolute end time already, no need to do it again */
GST_DEBUG_OBJECT (bus, "blocking for message, again");
timeval = &abstimeout; /* fool compiler */
}
if (!g_cond_timed_wait (bus->priv->queue_cond, bus->queue_lock, timeval)) {
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->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: 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.
*
* Since: 0.10.12
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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.
*
* Returns: 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.
*
* Since: 0.10.15
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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: 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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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: The #GstMessage that is on the bus, or NULL if the bus is empty.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
GstMessage *
gst_bus_peek (GstBus * bus)
{
GstMessage *message;
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
g_mutex_lock (bus->queue_lock);
message = g_queue_peek_head (bus->queue);
if (message)
gst_message_ref (message);
g_mutex_unlock (bus->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: The handler function to install
* @data: User data that will be sent to the handler function.
*
* 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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
void
gst_bus_set_sync_handler (GstBus * bus, GstBusSyncHandler func, gpointer data)
{
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->sync_handler != NULL)
goto no_replace;
bus->sync_handler = func;
bus->sync_handler_data = data;
GST_OBJECT_UNLOCK (bus);
return;
no_replace:
{
GST_OBJECT_UNLOCK (bus);
g_warning ("cannot replace existing sync handler");
return;
}
}
/* GSource for the bus
*/
typedef struct
{
GSource source;
GstBus *bus;
} GstBusSource;
static gboolean
gst_bus_source_prepare (GSource * source, gint * timeout)
{
GstBusSource *bsrc = (GstBusSource *) source;
*timeout = -1;
return gst_bus_have_pending (bsrc->bus);
}
static gboolean
gst_bus_source_check (GSource * source)
{
GstBusSource *bsrc = (GstBusSource *) source;
return gst_bus_have_pending (bsrc->bus);
}
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);
g_return_val_if_fail (message != NULL, FALSE);
if (!handler)
goto no_handler;
GST_DEBUG_OBJECT (bus, "source %p calling dispatch with %p", 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;
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: A #GSource that can be added to a mainloop.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
GSource *
gst_bus_create_watch (GstBus * bus)
{
GstBusSource *source;
g_return_val_if_fail (GST_IS_BUS (bus), NULL);
source = (GstBusSource *) g_source_new (&gst_bus_source_funcs,
sizeof (GstBusSource));
gst_object_ref (bus);
source->bus = bus;
return (GSource *) source;
}
/**
* gst_bus_add_watch_full:
* @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.
* This function is used to receive asynchronous messages in the main loop.
*
* 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 g_source_remove() or by returning FALSE
* from @func.
*
* Returns: The event source id.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
guint
gst_bus_add_watch_full (GstBus * bus, gint priority,
GstBusFunc func, gpointer user_data, GDestroyNotify notify)
{
guint id;
GSource *source;
g_return_val_if_fail (GST_IS_BUS (bus), 0);
source = gst_bus_create_watch (bus);
if (priority != G_PRIORITY_DEFAULT)
g_source_set_priority (source, priority);
g_source_set_callback (source, (GSourceFunc) func, user_data, notify);
id = g_source_attach (source, NULL);
g_source_unref (source);
GST_DEBUG_OBJECT (bus, "New source %p", source);
return id;
}
/**
* gst_bus_add_watch:
* @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.
* This function is used to receive asynchronous messages in the main loop.
*
* The watch can be removed using g_source_remove() or by returning FALSE
* from @func.
*
* Returns: The event source id.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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);
}
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_return_if_fail (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_free (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_free (poll_data);
}
}
/**
* gst_bus_poll:
* @bus: a #GstBus
* @events: a mask of #GstMessageType, representing the set of message types to
* poll for.
* @timeout: the poll timeout, as a #GstClockTimeDiff, or -1 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.
*
* 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.
*
* Returns: 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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
GstMessage *
gst_bus_poll (GstBus * bus, GstMessageType events, GstClockTimeDiff timeout)
{
GstBusPollData *poll_data;
GstMessage *ret;
gulong id;
poll_data = g_new0 (GstBusPollData, 1);
poll_data->source_running = TRUE;
poll_data->loop = g_main_loop_new (NULL, FALSE);
poll_data->events = events;
poll_data->message = NULL;
if (timeout >= 0)
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
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
void
gst_bus_disable_sync_message_emission (GstBus * bus)
{
g_return_if_fail (GST_IS_BUS (bus));
g_return_if_fail (bus->num_signal_watchers == 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.
* 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.
*
* MT safe.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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->num_signal_watchers > 0)
goto done;
g_assert (bus->signal_watch_id == 0);
bus->signal_watch_id =
gst_bus_add_watch_full (bus, priority, gst_bus_async_signal_func, NULL,
NULL);
done:
bus->num_signal_watchers++;
GST_OBJECT_UNLOCK (bus);
}
/**
* 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.
* 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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
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.
*/
#ifdef __SYMBIAN32__
EXPORT_C
#endif
void
gst_bus_remove_signal_watch (GstBus * bus)
{
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->num_signal_watchers == 0)
goto error;
bus->num_signal_watchers--;
if (bus->num_signal_watchers > 0)
goto done;
g_source_remove (bus->signal_watch_id);
bus->signal_watch_id = 0;
done:
GST_OBJECT_UNLOCK (bus);
return;
error:
{
g_critical ("Bus %s has no signal watches attached", GST_OBJECT_NAME (bus));
GST_OBJECT_UNLOCK (bus);
return;
}
}