org.eclipse.jetty.websocket.WebSocketGeneratorRFC6455 Maven / Gradle / Ivy
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//
// ========================================================================
// Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.websocket;
import java.io.IOException;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.eclipse.jetty.io.Buffer;
import org.eclipse.jetty.io.EndPoint;
import org.eclipse.jetty.io.EofException;
/**
* WebSocketGenerator.
* This class generates websocket packets.
* It is fully synchronized because it is likely that async
* threads will call the addMessage methods while other
* threads are flushing the generator.
*/
public class WebSocketGeneratorRFC6455 implements WebSocketGenerator
{
private final Lock _lock = new ReentrantLock();
private final WebSocketBuffers _buffers;
private final EndPoint _endp;
private final byte[] _mask = new byte[4];
private final MaskGen _maskGen;
private Buffer _buffer;
private int _m;
private boolean _opsent;
private boolean _closed;
public WebSocketGeneratorRFC6455(WebSocketBuffers buffers, EndPoint endp)
{
this(buffers, endp, null);
}
public WebSocketGeneratorRFC6455(WebSocketBuffers buffers, EndPoint endp, MaskGen maskGen)
{
_buffers = buffers;
_endp = endp;
_maskGen = maskGen;
}
public Buffer getBuffer()
{
_lock.lock();
try
{
return _buffer;
}
finally
{
_lock.unlock();
}
}
public void addFrame(byte flags, byte opcode, byte[] content, int offset, int length) throws IOException
{
_lock.lock();
try
{
if (_closed)
throw new EofException("Closed");
if (opcode == WebSocketConnectionRFC6455.OP_CLOSE)
_closed = true;
boolean mask = _maskGen != null;
if (_buffer == null)
_buffer = mask ? _buffers.getBuffer() : _buffers.getDirectBuffer();
boolean last = WebSocketConnectionRFC6455.isLastFrame(flags);
int space = mask ? 14 : 10;
do
{
opcode = _opsent ? WebSocketConnectionRFC6455.OP_CONTINUATION : opcode;
opcode = (byte)(((0xf & flags) << 4) + (0xf & opcode));
_opsent = true;
int payload = length;
if (payload + space > _buffer.capacity())
{
// We must fragement, so clear FIN bit
opcode = (byte)(opcode & 0x7F); // Clear the FIN bit
payload = _buffer.capacity() - space;
}
else if (last)
opcode = (byte)(opcode | 0x80); // Set the FIN bit
// ensure there is space for header
if (_buffer.space() <= space)
{
flushBuffer();
if (_buffer.space() <= space)
flush();
}
// write the opcode and length
if (payload > 0xffff)
{
_buffer.put(new byte[]{
opcode,
mask ? (byte)0xff : (byte)0x7f,
(byte)0,
(byte)0,
(byte)0,
(byte)0,
(byte)((payload >> 24) & 0xff),
(byte)((payload >> 16) & 0xff),
(byte)((payload >> 8) & 0xff),
(byte)(payload & 0xff)});
}
else if (payload >= 0x7e)
{
_buffer.put(new byte[]{
opcode,
mask ? (byte)0xfe : (byte)0x7e,
(byte)(payload >> 8),
(byte)(payload & 0xff)});
}
else
{
_buffer.put(new byte[]{
opcode,
(byte)(mask ? (0x80 | payload) : payload)});
}
// write mask
if (mask)
{
_maskGen.genMask(_mask);
_m = 0;
_buffer.put(_mask);
}
// write payload
int remaining = payload;
while (remaining > 0)
{
_buffer.compact();
int chunk = remaining < _buffer.space() ? remaining : _buffer.space();
if (mask)
{
for (int i = 0; i < chunk; i++)
_buffer.put((byte)(content[offset + (payload - remaining) + i] ^ _mask[+_m++ % 4]));
}
else
_buffer.put(content, offset + (payload - remaining), chunk);
remaining -= chunk;
if (_buffer.space() > 0)
{
// Gently flush the data, issuing a non-blocking write
flushBuffer();
}
else
{
// Forcibly flush the data, issuing a blocking write
flush();
if (remaining == 0)
{
// Gently flush the data, issuing a non-blocking write
flushBuffer();
}
}
}
offset += payload;
length -= payload;
}
while (length > 0);
_opsent = !last;
if (_buffer != null && _buffer.length() == 0)
{
_buffers.returnBuffer(_buffer);
_buffer = null;
}
}
finally
{
_lock.unlock();
}
}
public int flushBuffer() throws IOException
{
if (!_lock.tryLock())
return 0;
try
{
if (!_endp.isOpen())
throw new EofException();
if (_buffer != null)
{
int flushed = _buffer.hasContent() ? _endp.flush(_buffer) : 0;
if (_closed && _buffer.length() == 0)
_endp.shutdownOutput();
return flushed;
}
return 0;
}
finally
{
_lock.unlock();
}
}
public int flush() throws IOException
{
if (!_lock.tryLock())
return 0;
try
{
if (_buffer == null)
return 0;
int result = flushBuffer();
if (!_endp.isBlocking())
{
long now = System.currentTimeMillis();
long end = now + _endp.getMaxIdleTime();
while (_buffer.length() > 0)
{
boolean ready = _endp.blockWritable(end - now);
if (!ready)
{
now = System.currentTimeMillis();
if (now < end)
continue;
throw new IOException("Write timeout");
}
result += flushBuffer();
}
}
_buffer.compact();
return result;
}
finally
{
_lock.unlock();
}
}
public boolean isBufferEmpty()
{
_lock.lock();
try
{
return _buffer == null || _buffer.length() == 0;
}
finally
{
_lock.unlock();
}
}
public void returnBuffer()
{
_lock.lock();
try
{
if (_buffer != null && _buffer.length() == 0)
{
_buffers.returnBuffer(_buffer);
_buffer = null;
}
}
finally
{
_lock.unlock();
}
}
@Override
public String toString()
{
// Do NOT use synchronized (this)
// because it's very easy to deadlock when debugging is enabled.
// We do a best effort to print the right toString() and that's it.
Buffer buffer = _buffer;
return String.format("%s@%x closed=%b buffer=%d",
getClass().getSimpleName(),
hashCode(),
_closed,
buffer == null ? -1 : buffer.length());
}
}