package com.limegroup.gnutella.io;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
/**
* Manages writing data to the network from a piped blocking OutputStream.
*
* This uses a BufferOutputStream that waits on a lock when no data is available.
* The stream exposes a BufferLock that should be notified when data is available
* to be written.
*/
class NIOOutputStream implements WriteObserver {
private final NIOSocket handler;
private final SocketChannel channel;
private BufferOutputStream sink;
private Object bufferLock;
private ByteBuffer buffer;
private boolean shutdown;
/**
* Constructs a new pipe to allow SocketChannel's reading to funnel
* to a blocking InputStream.
*/
NIOOutputStream(NIOSocket handler, SocketChannel channel) {
this.handler = handler;
this.channel = channel;
}
/**
* Creates the pipes, buffer & registers channels for interest.
*/
private synchronized NIOOutputStream init() throws IOException {
if(buffer != null)
throw new IllegalStateException("already init'd!");
if(shutdown)
throw new IOException("already closed!");
this.buffer = NIODispatcher.instance().getBufferCache().getHeap();
sink = new BufferOutputStream(buffer, handler, channel);
bufferLock = sink.getBufferLock();
return this;
}
/**
* Retrieves the OutputStream to write to.
*/
synchronized OutputStream getOutputStream() throws IOException {
if(buffer == null)
init();
return sink;
}
/**
* Notification that a write can happen on the SocketChannel.
*/
public boolean handleWrite() throws IOException {// write everything we can.
if(buffer == null)
return false;
synchronized(bufferLock) {
buffer.flip();
while(buffer.hasRemaining() && channel.write(buffer) > 0);
if (buffer.position() > 0) {
if (buffer.hasRemaining())
buffer.compact();
else
buffer.clear();
} else
buffer.position(buffer.limit()).limit(buffer.capacity());
// If there's room in the buffer, we're interested in reading.
if(buffer.hasRemaining())
bufferLock.notify();
// if we were able to write everything, we're not interested in more writing.
// otherwise, we are interested.
if(buffer.position() == 0) {
NIODispatcher.instance().interestWrite(channel, false);
return false;
} else {
return true;
}
}
}
/**
* Shuts down all internal channels.
* The SocketChannel should be shut by NIOSocket.
*/
public synchronized void shutdown() {
if(shutdown)
return;
if(buffer != null)
NIODispatcher.instance().getBufferCache().release(buffer);
if(sink != null)
sink.shutdown();
shutdown = true;
}
/** Unused */
public void handleIOException(IOException iox) {
throw new RuntimeException("unsupported operation", iox);
}
}