/*
* Copyright (C) 2014 Tom Greenwood <tgreenwood@cafex.com>
* Copyright (C) 2007 Wayne Meissner
* Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
*
* This file is part of gstreamer-java.
*
* This code is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License version 3 only, as
* published by the Free Software Foundation.
*
* This code 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 Lesser General Public License
* version 3 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with this work. If not, see <http://www.gnu.org/licenses/>.
*/
package org.gstreamer;
import static org.gstreamer.lowlevel.GlibAPI.GLIB_API;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.gstreamer.event.BusSyncHandler;
import org.gstreamer.lowlevel.GstAPI.GErrorStruct;
import org.gstreamer.lowlevel.GstBusAPI;
import org.gstreamer.lowlevel.GstBusAPI.BusCallback;
import org.gstreamer.lowlevel.GstMessageAPI;
import org.gstreamer.lowlevel.GstMiniObjectAPI;
import org.gstreamer.lowlevel.GstNative;
import com.sun.jna.Callback;
import com.sun.jna.Pointer;
import com.sun.jna.ptr.PointerByReference;
/**
* The {@link Bus} is an object responsible for delivering {@link Message}s in
* a first-in first-out way from the streaming threads to the application.
* <p>
* Since the application typically only wants to deal with delivery of these
* messages from one thread, the Bus will marshall the messages between
* different threads. This is important since the actual streaming of media
* is done in another thread than the application.
* <p>
* 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.
* <p>
* 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.
* <p>
* It is also possible to get messages from the bus without any thread
* marshalling with the {@link #setSyncHandler} 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.
* <p>
* Every {@link Pipeline} has one bus.
* <p>
* Note that a Pipeline will set its bus into flushing state when changing
* from READY to NULL state.
*/
public class Bus extends GstObject {
static final Logger log = Logger.getLogger(Bus.class.getName());
static final Level LOG_DEBUG = Level.FINE;
public static final String GTYPE_NAME = "GstBus";
// Create an API with just the subset needed.
private static interface API extends GstBusAPI, GstMessageAPI, GstMiniObjectAPI {}
private static final API gst = GstNative.load(API.class);
private final Object lock = new Object();
private boolean watchAdded = false;
/**
* This constructor is used internally by gstreamer-java
*
* @param init internal initialization data
*/
public Bus(Initializer init) {
super(init);
gst.gst_bus_set_sync_handler(this, null, null, null);
gst.gst_bus_set_sync_handler(this, syncCallback, null, null);
}
/**
* Instructs the bus to flush out any queued messages.
*
* If flushing, flush out any messages queued in the bus. Will flush future
* messages until {@link #setFlushing} is called with false.
*
* @param flushing true if flushing is desired.
*/
public void setFlushing(boolean flushing) {
gst.gst_bus_set_flushing(this, flushing ? 1 : 0);
}
/**
* Signal emitted when end-of-stream is reached in a pipeline.
*
* The application will only receive this message in the PLAYING state and
* every time it sets a pipeline to PLAYING that is in the EOS state.
* The application can perform a flushing seek in the pipeline, which will
* undo the EOS state again.
*
* @see #connect(EOS)
* @see #disconnect(EOS)
*/
public static interface EOS {
/**
* Called when a {@link Pipeline} element posts a end-of-stream message.
*
* @param source the element which posted the message.
*/
public void endOfStream(GstObject source);
}
/**
* Signal emitted when an error occurs.
* <p>
* When the application receives an error message it should stop playback
* of the pipeline and not assume that more data will be played.
*
* @see #connect(ERROR)
* @see #disconnect(ERROR)
*/
public static interface ERROR {
/**
* Called when a {@link Pipeline} element posts an error message.
*
* @param source the element which posted the message.
* @param code a numeric code representing the error.
* @param message a string representation of the error.
*/
public void errorMessage(GstObject source, int code, String message);
}
/**
* Signal emitted when a warning message is delivered.
*
* @see #connect(WARNING)
* @see #disconnect(WARNING)
*/
public static interface WARNING {
/**
* Called when a {@link Pipeline} element posts an warning message.
*
* @param source the element which posted the message.
* @param code a numeric code representing the warning.
* @param message a string representation of the warning.
*/
public void warningMessage(GstObject source, int code, String message);
}
/**
* Signal emitted when an informational message is delivered.
*
* @see #connect(INFO)
* @see #disconnect(INFO)
*/
public static interface INFO {
/**
* Called when a {@link Pipeline} element posts an informational message.
*
* @param source the element which posted the message.
* @param code a numeric code representing the informational message.
* @param message a string representation of the informational message.
*/
public void infoMessage(GstObject source, int code, String message);
}
/**
* Signal emitted when a new tag is identified on the stream.
*
* @see #connect(TAG)
* @see #disconnect(TAG)
*/
public static interface TAG {
/**
* Called when a {@link Pipeline} element finds media meta-data.
*
* @param source the element which posted the message.
* @param tagList a list of media meta-data.
*/
public void tagsFound(GstObject source, TagList tagList);
}
/**
* Signal emitted when a state change happens.
*
* @see #connect(STATE_CHANGED)
* @see #disconnect(STATE_CHANGED)
*/
public static interface STATE_CHANGED {
/**
* Called when a {@link Pipeline} element executes a {@link State} change.
*
* @param source the element which posted the message.
* @param old the old state that the element is changing from.
* @param current the new (current) state the element is changing to.
* @param pending the pending (target) state.
*/
public void stateChanged(GstObject source, State old, State current, State pending);
}
/**
* Signal emitted when the pipeline is buffering data.
*
* @see #connect(BUFFERING)
* @see #disconnect(BUFFERING)
*/
public static interface BUFFERING {
/**
* Called when a {@link Pipeline} element needs to buffer data before
* it can continue processing.
* <p>
* {@code percent} is a value between 0 and 100. A value of 100 means that
* the buffering completed.
* <p>
* When {@code percent} is < 100 the application should PAUSE a PLAYING pipeline.
* When {@code percent} is 100, the application can set the pipeline (back) to PLAYING.
* <p>
* The application must be prepared to receive BUFFERING messages in the
* PREROLLING state and may only set the pipeline to PLAYING after receiving a
* message with {@code percent} set to 100, which can happen after the pipeline
* completed prerolling.
*
* @param source the element which posted the message.
* @param percent the percentage of buffering that has completed.
*/
public void bufferingData(GstObject source, int percent);
}
/**
* Signal sent when a new duration message is posted by an element that
* know the duration of a stream in a specific format.
* <p>
* This message is received by bins and is used to calculate the total
* duration of a pipeline.
* <p>
* Elements may post a duration message with a duration of
* {@link ClockTime#NONE} to indicate that the duration has changed and the
* cached duration should be discarded. The new duration can then be
* retrieved via a query.
* The application can get the new duration with a duration query.
*
* @see #connect(DURATION)
* @see #disconnect(DURATION)
*/
public static interface DURATION {
/**
* Called when a new duration message is posted on the Bus.
*
* @param source the element which posted the message.
* @param format the format of the duration
* @param duration the new duration.
*/
public void durationChanged(GstObject source, Format format, long duration);
}
/**
* This message is posted by elements that start playback of a segment as a
* result of a segment seek.
* <p>
* This message is not received by the application
* but is used for maintenance reasons in container elements.
*/
public static interface SEGMENT_START {
public void segmentStart(GstObject source, Format format, long position);
}
/**
* Signal emitted when the pipeline has completed playback of a segment.
* <p>
* This message is posted by elements that finish playback of a segment as a
* result of a segment seek. This message is received by the application
* after all elements that posted a {@link SEGMENT_START} have posted segment-done.
*
* @see #connect(SEGMENT_DONE)
* @see #disconnect(SEGMENT_DONE)
*/
public static interface SEGMENT_DONE {
/**
* Called when a segment-done message has been posted.
*
* @param source the element which posted the message.
* @param format the format of the position being done.
* @param position the position of the segment being done.
*/
public void segmentDone(GstObject source, Format format, long position);
}
/**
* Signal emitted by elements when they complete an ASYNC state change.
* <p>
* Applications will only receive this message from the top level pipeline.
* </p>
*
* @see #connect(ASYNC_DONE)
* @see #disconnect(ASYNC_DONE)
*/
public static interface ASYNC_DONE {
/**
* Called when a segment-done message has been posted.
*
* @param source the element which posted the message.
*/
public void asyncDone(GstObject source);
}
/**
* Catch all signals emitted on the Bus.
* <p>
* The signal handler will be called asynchronously from the thread that posted
* the message on the Bus.
*
* @see #connect(MESSAGE)
* @see #disconnect(MESSAGE)
*/
public static interface MESSAGE {
/**
* Called when a {@link Element} posts a {@link Message} on the Bus.
*
* @param bus the Bus the message was posted on.
* @param message the message that was posted.
*/
public void busMessage(Bus bus, Message message);
}
/**
* Add a listener for end-of-stream messages.
*
* @param listener The listener to be called when end-of-stream is encountered.
*/
public void connect(final EOS listener) {
connect(EOS.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
listener.endOfStream(msg.getSource());
return true;
}
});
}
/**
* Disconnect the listener for end-of-stream messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(EOS listener) {
disconnect(EOS.class, listener);
}
/**
* Add a listener for error messages.
*
* @param listener The listener to be called when an error in the stream is encountered.
*/
public void connect(final ERROR listener) {
connect(ERROR.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
PointerByReference err = new PointerByReference();
gst.gst_message_parse_error(msg, err, null);
GErrorStruct error = new GErrorStruct(err.getValue());
listener.errorMessage(msg.getSource(), error.getCode(), error.getMessage());
GLIB_API.g_error_free(err.getValue());
return true;
}
});
}
/**
* Disconnect the listener for error messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(ERROR listener) {
disconnect(ERROR.class, listener);
}
/**
* Add a listener for warning messages.
*
* @param listener The listener to be called when an {@link Element} emits a warning.
*/
public void connect(final WARNING listener) {
connect(WARNING.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
PointerByReference err = new PointerByReference();
gst.gst_message_parse_warning(msg, err, null);
GErrorStruct error = new GErrorStruct(err.getValue());
listener.warningMessage(msg.getSource(), error.getCode(), error.getMessage());
GLIB_API.g_error_free(err.getValue());
return true;
}
});
}
/**
* Disconnect the listener for warning messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(WARNING listener) {
disconnect(WARNING.class, listener);
}
/**
* Add a listener for informational messages.
*
* @param listener The listener to be called when an {@link Element} emits a an informational message.
*/
public void connect(final INFO listener) {
connect(INFO.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
PointerByReference err = new PointerByReference();
gst.gst_message_parse_info(msg, err, null);
GErrorStruct error = new GErrorStruct(err.getValue());
listener.infoMessage(msg.getSource(), error.getCode(), error.getMessage());
GLIB_API.g_error_free(err.getValue());
return true;
}
});
}
/**
* Disconnect the listener for informational messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(INFO listener) {
disconnect(INFO.class, listener);
}
/**
* Add a listener for {@link State} changes in the Pipeline.
*
* @param listener The listener to be called when the Pipeline changes state.
*/
public void connect(final STATE_CHANGED listener) {
connect(STATE_CHANGED.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
State[] o = new State[1];
State[] n = new State[1];
State[] p = new State[1];
gst.gst_message_parse_state_changed(msg, o, n, p);
listener.stateChanged(msg.getSource(), o[0], n[0], p[0]);
return true;
}
});
}
/**
* Disconnect the listener for {@link State} change messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(STATE_CHANGED listener) {
disconnect(STATE_CHANGED.class, listener);
}
/**
* Add a listener for new media tags.
*
* @param listener The listener to be called when new media tags are found.
*/
public void connect(final TAG listener) {
connect(TAG.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
PointerByReference list = new PointerByReference();
gst.gst_message_parse_tag(msg, list);
TagList tl = new TagList(TagList.initializer(list.getValue()));
listener.tagsFound(msg.getSource(), tl);
return true;
}
});
}
/**
* Disconnect the listener for tag messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(TAG listener) {
disconnect(TAG.class, listener);
}
/**
* Add a listener for {@link BUFFERING} messages in the Pipeline.
*
* @param listener The listener to be called when the Pipeline buffers data.
*/
public void connect(final BUFFERING listener) {
connect(BUFFERING.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
int[] percent = { 0 };
gst.gst_message_parse_buffering(msg, percent);
listener.bufferingData(msg.getSource(), percent[0]);
return true;
}
});
}
/**
* Disconnect the listener for buffering messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(BUFFERING listener) {
disconnect(BUFFERING.class, listener);
}
/**
* Add a listener for duration changes.
*
* @param listener The listener to be called when the duration changes.
*/
public void connect(final DURATION listener) {
connect(DURATION.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
System.out.println("duration update");
Format[] format = new Format[1];
long[] duration = { 0 };
gst.gst_message_parse_duration(msg, format, duration);
listener.durationChanged(msg.getSource(), format[0], duration[0]);
return true;
}
});
}
/**
* Disconnect the listener for duration change messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(DURATION listener) {
disconnect(DURATION.class, listener);
}
/**
* Add a listener for {@link SEGMENT_START} messages in the Pipeline.
*
* @param listener The listener to be called when the Pipeline has started a segment.
*/
public void connect(final SEGMENT_START listener) {
connect(SEGMENT_START.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
Format[] format = new Format[1];
long[] position = { 0 };
gst.gst_message_parse_segment_start(msg, format, position);
listener.segmentStart(msg.getSource(), format[0], position[0]);
return true;
}
});
}
/**
* Disconnect the listener for segment-start messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(SEGMENT_START listener) {
disconnect(SEGMENT_START.class, listener);
}
/**
* Add a listener for {@link SEGMENT_DONE} messages in the Pipeline.
*
* @param listener The listener to be called when the Pipeline has finished a segment.
*/
public void connect(final SEGMENT_DONE listener) {
connect(SEGMENT_DONE.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
Format[] format = new Format[1];
long[] position = { 0 };
gst.gst_message_parse_segment_done(msg, format, position);
listener.segmentDone(msg.getSource(), format[0], position[0]);
return true;
}
});
}
/**
* Disconnect the listener for segment-done messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(SEGMENT_DONE listener) {
disconnect(SEGMENT_DONE.class, listener);
}
/**
* Add a listener for {@link ASYNC_DONE} messages in the Pipeline.
*
* @param listener The listener to be called when the an element has finished
* an async state change.
*/
public void connect(final ASYNC_DONE listener) {
connect(ASYNC_DONE.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
listener.asyncDone(msg.getSource());
return true;
}
});
}
/**
* Disconnect the listener for async-done messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(ASYNC_DONE listener) {
disconnect(ASYNC_DONE.class, listener);
}
/**
* Add a listener for all messages posted on the Bus.
*
* @param listener The listener to be called when a {@link Message} is posted.
*/
public void connect(final MESSAGE listener) {
connect(MESSAGE.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
listener.busMessage(bus, msg);
return true;
}
});
}
/**
* Add a listener for messages of type {@code signal} posted on the Bus.
*
* @param signal the signal to connect to.
* @param listener The listener to be called when a {@link Message} is posted.
*/
public void connect(String signal, final MESSAGE listener) {
//
// Deal with being called as e.g. "message::eos"
//
if (signal.contains("::")) {
signal = signal.substring(signal.lastIndexOf("::") + 2);
}
connect(signal, MESSAGE.class, listener, new BusCallback() {
public boolean callback(Bus bus, Message msg, Pointer user_data) {
listener.busMessage(bus, msg);
return true;
}
});
}
/**
* Disconnect the listener for segment-done messages.
*
* @param listener The listener that was registered to receive the message.
*/
public void disconnect(MESSAGE listener) {
disconnect(MESSAGE.class, listener);
}
/**
* Posts a {@link Message} on this Bus.
*
* @param message the message to post.
* @return <tt>true</tt> if the message could be posted, <tt>false</tt> if
* the bus is flushing.
*/
public boolean post(Message message) {
return gst.gst_bus_post(this, message);
}
private BusSyncHandler syncHandler = new BusSyncHandler() {
public BusSyncReply syncMessage(Message msg) {
return BusSyncReply.PASS;
}
};
public BusSyncHandler getSyncHandler() {
return syncHandler;
}
public void setSyncHandler(BusSyncHandler handler) {
syncHandler = handler;
}
private static org.gstreamer.lowlevel.GstBusAPI.BusSyncHandler syncCallback = new GstBusAPI.BusSyncHandler() {
public BusSyncReply callback(final Bus bus, final Message msg, Pointer userData) {
if (bus.syncHandler != null) {
BusSyncReply reply = bus.syncHandler.syncMessage(msg);
if (reply != BusSyncReply.DROP) {
Gst.getExecutor().execute(new Runnable() {
public void run() {
bus.dispatchMessage(msg);
}
});
}
}
//
// Unref the message, since we are dropping it.
// (the normal GC will drop other refs to it)
//
gst.gst_mini_object_unref(msg);
return BusSyncReply.DROP;
}
};
/**
* Connects to a signal.
*
* The signal name is deduced from the listenerClass name.
*
* @param listenerClass the class of the listener.
* @param listener the listener to associate with the {@code callback}
* @param callback The callback to call when the signal is emitted.
*/
private <T> void connect(Class<T> listenerClass, T listener, BusCallback callback) {
final String signal = listenerClass.getSimpleName().toLowerCase().replaceAll("_", "-");
connect(signal, listenerClass, listener, callback);
}
/**
* Connects a callback to a signal.
* <p>
* This differs to {@link GObject#connect} in that it hooks up Bus signals
* to the sync callback, not the generic GObject signal mechanism.
*
* @param signal the name of the signal to connect to.
* @param listenerClass the class of the {@code listener}
* @param listener the listener to associate with the {@code callback}
* @param callback the callback to call when the signal is emitted.
*/
@Override
public synchronized <T> void connect(String signal, Class<T> listenerClass, T listener,
final Callback callback) {
if (listenerClass.getEnclosingClass() != Bus.class) {
super.connect(signal, listenerClass, listener, callback);
return;
}
MessageType type = MessageType.forName(signal);
if (type == MessageType.UNKNOWN && "message".equals(signal)) {
type = MessageType.ANY;
}
if (type == MessageType.UNKNOWN) {
throw new IllegalArgumentException("Illegal signal: " + signal);
}
final Map<Class<?>, Map<Object, MessageProxy>> signals = getListenerMap();
Map<Object, MessageProxy> m = signals.get(type);
if (m == null) {
m = new HashMap<Object, MessageProxy>();
signals.put(listenerClass, m);
}
MessageProxy proxy = new MessageProxy(type, (BusCallback) callback);
m.put(listener, proxy);
messageProxies.add(proxy);
addWatch();
}
@Override
public synchronized <T> void disconnect(Class<T> listenerClass, T listener) {
if (listenerClass.getEnclosingClass() != Bus.class) {
super.disconnect(listenerClass, listener);
return;
}
final Map<Class<?>, Map<Object, MessageProxy>> signals = getListenerMap();
Map<Object, MessageProxy> m = signals.get(listenerClass);
if (m != null) {
MessageProxy proxy = m.remove(listener);
if (proxy != null) {
messageProxies.remove(proxy);
}
if (m.isEmpty()) {
removeWatch();
signals.remove(listenerClass);
}
}
}
/**
* Dispatches a message to all interested listeners.
*
* <p>
* We do this here from a sync callback, because the default gstbus dispatch
* uses the default main context to signal that there are messages waiting on
* the bus. Since that is used by the GTK L&F under swing, we never get those
* notifications, and the messages just queue up.
* @param message
*/
private void dispatchMessage(Message msg) {
// Dispatch to listeners
for (Object listener : messageProxies) {
((MessageProxy) listener).busMessage(this, msg);
}
}
private static class MessageProxy implements MESSAGE {
private final MessageType type;
private final BusCallback callback;
public MessageProxy(MessageType type, BusCallback callback) {
this.type = type;
this.callback = callback;
}
public void busMessage(final Bus bus, final Message msg) {
final MessageType messageType;
try {
messageType = msg.getType();
if ((type.intValue() & msg.getType().intValue()) != 0) {
callback.callback(bus, msg, null);
}
} catch (Throwable e) {
e.printStackTrace();
System.out.println("ERROR getting type from message");
System.exit(1);
}
}
}
private final Map<Class<?>, Map<Object, MessageProxy>> getListenerMap() {
if (signalListeners == null) {
signalListeners = new ConcurrentHashMap<Class<?>, Map<Object, MessageProxy>>();
}
return signalListeners;
}
@Override
public void dispose() {
removeWatch();
super.dispose();
}
/**
* Adds the bus signal watch.
* This will reference the bus until the signal watch is removed
* and so will stop the Bus being GC'd and disposed.
*/
private void addWatch()
{
synchronized (lock)
{
if (!watchAdded)
{
log.fine("Add watch");
gst.gst_bus_add_signal_watch(this);
watchAdded = true;
}
}
}
/**
* Removes the bus signal watch (which will remove the bus reference
* held by the signal watch).
*/
private void removeWatch()
{
synchronized (lock)
{
if (watchAdded)
{
log.fine("Remove watch");
gst.gst_bus_remove_signal_watch(this);
watchAdded = false;
}
}
}
private Map<Class<?>, Map<Object, MessageProxy>> signalListeners;
private List<MessageProxy> messageProxies = new CopyOnWriteArrayList<MessageProxy>();
}