org.eclipse.jgit.transport.PacketLineOut Maven / Gradle / Ivy
/*
* Copyright (C) 2008-2010, Google Inc.
* Copyright (C) 2008-2009, Robin Rosenberg
* Copyright (C) 2008, Shawn O. Pearce
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.transport;
import java.io.IOException;
import java.io.OutputStream;
import org.eclipse.jgit.lib.Constants;
/**
* Write Git style pkt-line formatting to an output stream.
*
* This class is not thread safe and may issue multiple writes to the underlying
* stream for each method call made.
*
* This class performs no buffering on its own. This makes it suitable to
* interleave writes performed by this class with writes performed directly
* against the underlying OutputStream.
*/
public class PacketLineOut {
private final OutputStream out;
private final byte[] lenbuffer;
private boolean flushOnEnd;
/**
* Create a new packet line writer.
*
* @param outputStream
* stream.
*/
public PacketLineOut(final OutputStream outputStream) {
out = outputStream;
lenbuffer = new byte[5];
flushOnEnd = true;
}
/**
* Set the flush behavior during {@link #end()}.
*
* @param flushOnEnd
* if true, a flush-pkt written during {@link #end()} also
* flushes the underlying stream.
*/
public void setFlushOnEnd(boolean flushOnEnd) {
this.flushOnEnd = flushOnEnd;
}
/**
* Write a UTF-8 encoded string as a single length-delimited packet.
*
* @param s
* string to write.
* @throws IOException
* the packet could not be written, the stream is corrupted as
* the packet may have been only partially written.
*/
public void writeString(final String s) throws IOException {
writePacket(Constants.encode(s));
}
/**
* Write a binary packet to the stream.
*
* @param packet
* the packet to write; the length of the packet is equal to the
* size of the byte array.
* @throws IOException
* the packet could not be written, the stream is corrupted as
* the packet may have been only partially written.
*/
public void writePacket(final byte[] packet) throws IOException {
formatLength(packet.length + 4);
out.write(lenbuffer, 0, 4);
out.write(packet);
}
/**
* Write a packet end marker, sometimes referred to as a flush command.
*
* Technically this is a magical packet type which can be detected
* separately from an empty string or an empty packet.
*
* Implicitly performs a flush on the underlying OutputStream to ensure the
* peer will receive all data written thus far.
*
* @throws IOException
* the end marker could not be written, the stream is corrupted
* as the end marker may have been only partially written.
*/
public void end() throws IOException {
formatLength(0);
out.write(lenbuffer, 0, 4);
if (flushOnEnd)
flush();
}
/**
* Flush the underlying OutputStream.
*
* Performs a flush on the underlying OutputStream to ensure the peer will
* receive all data written thus far.
*
* @throws IOException
* the underlying stream failed to flush.
*/
public void flush() throws IOException {
out.flush();
}
private static final byte[] hexchar = { '0', '1', '2', '3', '4', '5', '6',
'7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
private void formatLength(int w) {
formatLength(lenbuffer, w);
}
static void formatLength(byte[] lenbuffer, int w) {
int o = 3;
while (o >= 0 && w != 0) {
lenbuffer[o--] = hexchar[w & 0xf];
w >>>= 4;
}
while (o >= 0)
lenbuffer[o--] = '0';
}
}