| /* GstPipeline.java -- Represents a Gstreamer Pipeline. |
| Copyright (C) 2007 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.javax.sound.sampled.gstreamer.lines; |
| |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| import java.util.prefs.Preferences; |
| |
| import javax.sound.sampled.LineUnavailableException; |
| |
| import gnu.classpath.Pointer; |
| |
| /** |
| * This class represent a GStreamer pipeline and is resposible to handle the |
| * flow of data to and from the GStreamer native backend. |
| * |
| * @author Mario Torre <neugens@limasoftware.net> |
| */ |
| public class GstPipeline |
| { |
| /* |
| * Implementation note: |
| * This class is at first a bit confusing as it serves as a gateway |
| * to a real filesystem named pipe. |
| * The pipelines is shared by the gstreamer backend and by the java code. |
| * If the operation we are performing is to play a given stream of bytes, |
| * we need to open the java side of the pipeline for writing, which is done |
| * in the prepareWrite method. At the same time, the native side of the code |
| * need to open the pipeline in read mode, to get access to the data, |
| * and hence, act as a source element. This is why you will see terms |
| * like "read" or "source" in methods that are used to write in the pipeline, |
| * in other words, each the native operation is the opposite of the java |
| * side operation. |
| * Opening the pipe to record audio data from the sound card works the same |
| * except that all the operation are inverted. |
| */ |
| |
| // These enums are used in the native code also, changes here must reflect |
| // changes in the native code. |
| public static enum State |
| { |
| PLAY, PAUSE, STOP, CLOSE |
| } |
| |
| private static final int READ = 0; |
| private static final int WRITE = 1; |
| private static final int QUEUED = 1; |
| |
| private static final String CAPACITY_KEY = "Capacity"; |
| |
| private static final Object [] lock = new Object[0]; |
| |
| /* |
| * Preference subsystem. We use this to store some system specific settings. |
| */ |
| protected Preferences prefs = |
| Preferences.userNodeForPackage(GstPipeline.class).node("GStreamer"); |
| |
| // used by the native code, stores the size of the named pipeline |
| // created by the operating system. |
| private long capacity = -1; |
| |
| /** Represents the playing state of this Line. */ |
| private State state = State.STOP; |
| |
| /** The name of the named pipe. */ |
| // Will be setup and filled in the native code. See the native library |
| // for details. |
| private String name = null; |
| |
| /** This is the named pipe that will be read by the gstreamer backend. */ |
| private FileOutputStream output = null; |
| |
| /** |
| * Defines if we are getting data from a sink pipe |
| * or writing to a source pipe. |
| */ |
| private boolean source = true; |
| |
| /** Indicate that we are ready to process audio data to/from the pipe. */ |
| private boolean ready = false; |
| |
| /** |
| * This is the native GStreamer Pipeline. |
| */ |
| // This field is used by the native code, so any change to it must be |
| // followed by similar changes in the native peer. |
| private Pointer pipeline = null; |
| |
| /** |
| * Creates a new GstPipeline with a capacity of |
| * {@link GstDataLine#DEFAULT_BUFFER_SIZE}. |
| * |
| * @see GstDataLine#DEFAULT_BUFFER_SIZE |
| */ |
| public GstPipeline() |
| { |
| this(GstDataLine.DEFAULT_BUFFER_SIZE); |
| } |
| |
| /** |
| * Creates a new GstPipeline with a capacity of bufferSize. |
| * @see GstDataLine#DEFAULT_BUFFER_SIZE |
| */ |
| public GstPipeline(int bufferSize) |
| { |
| // see if we need to detect the size of the named pipe or we can use |
| // an already computet default for this system. |
| // Note that this is very different from the bufferSize parameter, |
| // see below. |
| capacity = prefs.getLong(CAPACITY_KEY, -1); |
| if (capacity == -1) |
| { |
| synchronized (lock) |
| { |
| capacity = detect_pipe_size(); |
| } |
| |
| prefs.putLong(CAPACITY_KEY, capacity); |
| } |
| |
| // FIXME: bufferSize actually not used nor needed by the backend. |
| // Applications that expects a buffer of different size will be a |
| // bit disappointed by that.. |
| init_instance(); |
| |
| // need to remove the named pipe in case of abnormal termination |
| Runtime.getRuntime().addShutdownHook(new CleanPipeline()); |
| } |
| |
| /** |
| * Creates a source pipeline. A source pipeline is a pipe you send data for |
| * processing using the write method. |
| */ |
| public void createForWrite() throws LineUnavailableException |
| { |
| // create the named pipe |
| if (!create_named_pipe(this.pipeline)) |
| throw new LineUnavailableException("Unable to create filesystem pipe"); |
| |
| open_native_pipe(this.pipeline, READ); |
| prepareWrite(); |
| |
| this.source = true; |
| } |
| |
| /** |
| * @return the state |
| */ |
| public State getState() |
| { |
| return this.state; |
| } |
| |
| /** |
| * Closes this pipeline. |
| * Short hand for #setState(State.STOP). |
| */ |
| public void close() |
| { |
| setState(State.STOP); |
| } |
| |
| /** |
| * @param state the state to set |
| */ |
| public void setState(final State state) |
| { |
| int _state = -1; |
| switch (state) |
| { |
| case PLAY: |
| _state = 0; |
| break; |
| |
| case PAUSE: |
| _state = 1; |
| break; |
| |
| case STOP: case CLOSE: |
| _state = 2; |
| closePipe(); |
| break; |
| } |
| |
| if (set_state(pipeline, _state)) |
| GstPipeline.this.state = state; |
| } |
| |
| /** |
| * Return a reference to the GstPipeline native class as a Pointer object. |
| * This method is intended as an helper accessor and the returned pointer |
| * needs to be casted and used in the native code only. |
| * |
| * @return Pointer to the native GstPipeline class. |
| */ |
| public Pointer getNativeClass() |
| { |
| return this.pipeline; |
| } |
| |
| /** |
| * Write length bytes from the given buffer into this pipeline, |
| * starting at offset. |
| * This method block if the pipeline can't accept more data. |
| * |
| * @param buffer |
| * @param offset |
| * @param length |
| * @return |
| */ |
| public int write(byte[] buffer, int offset, int length) |
| { |
| if (this.state == State.STOP) |
| return -1; |
| else if (this.state == State.PAUSE) |
| return 0; |
| else if (!ready) |
| return -1; |
| |
| try |
| { |
| if (output != null) |
| { |
| output.write(buffer, offset, length); |
| return length; |
| } |
| return 0; |
| } |
| catch (Exception e) |
| { |
| /* nothing to do */ |
| } |
| |
| return -1; |
| } |
| |
| public int read(byte[] buffer, int offset, int length) |
| { |
| return 0; |
| } |
| |
| public int available() |
| { |
| if (this.source) |
| return available(this.pipeline, READ); |
| else |
| return available(this.pipeline, WRITE); |
| } |
| |
| /** |
| * Wait for remaining data to be enqueued in the pipeline. |
| */ |
| public void drain() |
| { |
| if (this.state == State.STOP) |
| return; |
| |
| try |
| { |
| // wait untill there is anymore data in the pipe |
| while (available(this.pipeline, QUEUED) > 0) |
| Thread.sleep(3000); |
| |
| // plus a bit to allow data to be processed |
| Thread.sleep(1000); |
| } |
| catch (InterruptedException e) |
| { |
| /* nothing to do*/ |
| } |
| } |
| |
| /** |
| * Flush all the data currently waiting to be processed. |
| */ |
| public void flush() |
| { |
| try |
| { |
| if (source) |
| this.output.flush(); |
| } |
| catch (IOException e) |
| { |
| /* nothing */ |
| } |
| } |
| |
| private void closePipe() |
| { |
| try |
| { |
| GstPipeline.this.flush(); |
| if (source) |
| GstPipeline.this.output.close(); |
| } |
| catch (IOException e) |
| { |
| /* nothing to do */ |
| } |
| } |
| |
| private void prepareWrite() |
| { |
| try |
| { |
| // if this is not completed for some reason, we will catch |
| // in the write method. As this call can block, we assume we will |
| // succeed and that the dataline can get data. |
| GstPipeline.this.ready = true; |
| GstPipeline.this.output = new FileOutputStream(name); |
| } |
| catch (Exception e) |
| { |
| GstPipeline.this.ready = false; |
| } |
| } |
| |
| /* ***** native ***** */ |
| |
| /** |
| * Initialize the native peer and enables the object cache. |
| * It is meant to be used by the static initializer. |
| */ |
| native private static final void init_id_cache(); |
| |
| /** |
| * Set the playing state of this pipeline. |
| */ |
| native private static final boolean set_state(Pointer pipeline, int state); |
| |
| /** |
| * Get the number of bytes currently available for reading or writing |
| * from the pipeline. |
| */ |
| native private static final int available(Pointer pipeline, int mode); |
| |
| /** |
| * Open the native pipeline with the given mode. |
| */ |
| native private static final void open_native_pipe(Pointer jpipeline, |
| int mode); |
| |
| /** |
| * Close the native pipeline. |
| */ |
| native private static final void close_native_pipe(Pointer jpipeline); |
| |
| /** |
| * Initialize the native peer and enables the object cache. |
| * It is meant to be used by the class constructor. |
| */ |
| native private final void init_instance(); |
| |
| /** |
| * Crates the named pipe used to pass data between the application code |
| * and gstreamer. |
| */ |
| native private final boolean create_named_pipe(Pointer jpipeline); |
| |
| /** |
| * Detect and return the size of the filesystem named pipe. |
| */ |
| native private final long detect_pipe_size(); |
| |
| private class CleanPipeline extends Thread |
| { |
| public void run() |
| { |
| GstPipeline.close_native_pipe(GstPipeline.this.pipeline); |
| } |
| } |
| |
| static |
| { |
| System.loadLibrary("gstreamerpeer"); //$NON-NLS-1$ |
| init_id_cache(); |
| } |
| } |