org.eclipse.jgit/src/org/eclipse/jgit/transport/PacketLineIn.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2008-2010, Google Inc.
  * Copyright (C) 2008-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
  * 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.InputStream;
 import java.text.MessageFormat;

 import org.eclipse.jgit.errors.PackProtocolException;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.MutableObjectId;
 import org.eclipse.jgit.util.IO;
 import org.eclipse.jgit.util.RawParseUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 /**
  * Read Git style pkt-line formatting from an input stream.
  * <p>
  * This class is not thread safe and may issue multiple reads to the underlying
  * stream for each method call made.
  * <p>
  * This class performs no buffering on its own. This makes it suitable to
  * interleave reads performed by this class with reads performed directly
  * against the underlying InputStream.
  */
 public class PacketLineIn {
 	private static final Logger log = LoggerFactory.getLogger(PacketLineIn.class);

 	/** Magic return from {@link #readString()} when a flush packet is found. */
 	public static final String END = new StringBuilder(0).toString(); 	/* must not string pool */

 	static enum AckNackResult {
 		/** NAK */
 		NAK,
 		/** ACK */
 		ACK,
 		/** ACK + continue */
 		ACK_CONTINUE,
 		/** ACK + common */
 		ACK_COMMON,
 		/** ACK + ready */
 		ACK_READY;
 	}

 	private final byte[] lineBuffer = new byte[SideBandOutputStream.SMALL_BUF];
 	private final InputStream in;
 	private long limit;

 	/**
 	 * Create a new packet line reader.
 	 *
 	 * @param in
 	 *            the input stream to consume.
 	 */
 	public PacketLineIn(InputStream in) {
 		this(in, 0);
 	}

 	/**
 	 * Create a new packet line reader.
 	 *
 	 * @param in
 	 *            the input stream to consume.
 	 * @param limit
 	 *            bytes to read from the input; unlimited if set to 0.
 	 * @since 4.7
 	 */
 	public PacketLineIn(InputStream in, long limit) {
 		this.in = in;
 		this.limit = limit;
 	}

 	AckNackResult readACK(final MutableObjectId returnedId) throws IOException {
 		final String line = readString();
 		if (line.length() == 0)
 			throw new PackProtocolException(JGitText.get().expectedACKNAKFoundEOF);
 		if ("NAK".equals(line)) //$NON-NLS-1$
 			return AckNackResult.NAK;
 		if (line.startsWith("ACK ")) { //$NON-NLS-1$
 			returnedId.fromString(line.substring(4, 44));
 			if (line.length() == 44)
 				return AckNackResult.ACK;

 			final String arg = line.substring(44);
 			if (arg.equals(" continue")) //$NON-NLS-1$
 				return AckNackResult.ACK_CONTINUE;
 			else if (arg.equals(" common")) //$NON-NLS-1$
 				return AckNackResult.ACK_COMMON;
 			else if (arg.equals(" ready")) //$NON-NLS-1$
 				return AckNackResult.ACK_READY;
 		}
 		if (line.startsWith("ERR ")) //$NON-NLS-1$
 			throw new PackProtocolException(line.substring(4));
 		throw new PackProtocolException(MessageFormat.format(JGitText.get().expectedACKNAKGot, line));
 	}

 	/**
 	 * Read a single UTF-8 encoded string packet from the input stream.
 	 * <p>
 	 * If the string ends with an LF, it will be removed before returning the
 	 * value to the caller. If this automatic trimming behavior is not desired,
 	 * use {@link #readStringRaw()} instead.
 	 *
 	 * @return the string. {@link #END} if the string was the magic flush
 	 *         packet.
 	 * @throws IOException
 	 *             the stream cannot be read.
 	 */
 	public String readString() throws IOException {
 		int len = readLength();
 		if (len == 0) {
 			log.debug("git< 0000"); //$NON-NLS-1$
 			return END;
 		}

 		len -= 4; // length header (4 bytes)
 		if (len == 0) {
 			log.debug("git< "); //$NON-NLS-1$
 			return ""; //$NON-NLS-1$
 		}

 		byte[] raw;
 		if (len <= lineBuffer.length)
 			raw = lineBuffer;
 		else
 			raw = new byte[len];

 		IO.readFully(in, raw, 0, len);
 		if (raw[len - 1] == '\n')
 			len--;

 		String s = RawParseUtils.decode(Constants.CHARSET, raw, 0, len);
 		log.debug("git< " + s); //$NON-NLS-1$
 		return s;
 	}

 	/**
 	 * Read a single UTF-8 encoded string packet from the input stream.
 	 * <p>
 	 * Unlike {@link #readString()} a trailing LF will be retained.
 	 *
 	 * @return the string. {@link #END} if the string was the magic flush
 	 *         packet.
 	 * @throws IOException
 	 *             the stream cannot be read.
 	 */
 	public String readStringRaw() throws IOException {
 		int len = readLength();
 		if (len == 0) {
 			log.debug("git< 0000"); //$NON-NLS-1$
 			return END;
 		}

 		len -= 4; // length header (4 bytes)

 		byte[] raw;
 		if (len <= lineBuffer.length)
 			raw = lineBuffer;
 		else
 			raw = new byte[len];

 		IO.readFully(in, raw, 0, len);

 		String s = RawParseUtils.decode(Constants.CHARSET, raw, 0, len);
 		log.debug("git< " + s); //$NON-NLS-1$
 		return s;
 	}

 	void discardUntilEnd() throws IOException {
 		for (;;) {
 			int n = readLength();
 			if (n == 0) {
 				break;
 			}
 			IO.skipFully(in, n - 4);
 		}
 	}

 	int readLength() throws IOException {
 		IO.readFully(in, lineBuffer, 0, 4);
 		int len;
 		try {
 			len = RawParseUtils.parseHexInt16(lineBuffer, 0);
 		} catch (ArrayIndexOutOfBoundsException err) {
 			throw invalidHeader();
 		}

 		if (len == 0) {
 			return 0;
 		} else if (len < 4) {
 			throw invalidHeader();
 		}

 		if (limit != 0) {
 			int n = len - 4;
 			if (limit < n) {
 				limit = -1;
 				try {
 					IO.skipFully(in, n);
 				} catch (IOException e) {
 					// Ignore failure discarding packet over limit.
 				}
 				throw new InputOverLimitIOException();
 			}
 			// if set limit must not be 0 (means unlimited).
 			limit = n < limit ? limit - n : -1;
 		}
 		return len;
 	}

 	private IOException invalidHeader() {
 		return new IOException(MessageFormat.format(JGitText.get().invalidPacketLineHeader,
 				"" + (char) lineBuffer[0] + (char) lineBuffer[1] //$NON-NLS-1$
 				+ (char) lineBuffer[2] + (char) lineBuffer[3]));
 	}

 	/**
 	 * IOException thrown by read when the configured input limit is exceeded.
 	 *
 	 * @since 4.7
 	 */
 	public static class InputOverLimitIOException extends IOException {
 		private static final long serialVersionUID = 1L;
 	}
 }
	/*
	* Copyright (C) 2008-2010, Google Inc.
	* Copyright (C) 2008-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
	* Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
	* 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.InputStream;
	import java.text.MessageFormat;

	import org.eclipse.jgit.errors.PackProtocolException;
	import org.eclipse.jgit.internal.JGitText;
	import org.eclipse.jgit.lib.Constants;
	import org.eclipse.jgit.lib.MutableObjectId;
	import org.eclipse.jgit.util.IO;
	import org.eclipse.jgit.util.RawParseUtils;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	/**
	* Read Git style pkt-line formatting from an input stream.
	* <p>
	* This class is not thread safe and may issue multiple reads to the underlying
	* stream for each method call made.
	* <p>
	* This class performs no buffering on its own. This makes it suitable to
	* interleave reads performed by this class with reads performed directly
	* against the underlying InputStream.
	*/
	public class PacketLineIn {
	private static final Logger log = LoggerFactory.getLogger(PacketLineIn.class);

	/** Magic return from {@link #readString()} when a flush packet is found. */
	public static final String END = new StringBuilder(0).toString(); /* must not string pool */

	static enum AckNackResult {
	/** NAK */
	NAK,
	/** ACK */
	ACK,
	/** ACK + continue */
	ACK_CONTINUE,
	/** ACK + common */
	ACK_COMMON,
	/** ACK + ready */
	ACK_READY;
	}

	private final byte[] lineBuffer = new byte[SideBandOutputStream.SMALL_BUF];
	private final InputStream in;
	private long limit;

	/**
	* Create a new packet line reader.
	*
	* @param in
	* the input stream to consume.
	*/
	public PacketLineIn(InputStream in) {
	this(in, 0);
	}

	/**
	* Create a new packet line reader.
	*
	* @param in
	* the input stream to consume.
	* @param limit
	* bytes to read from the input; unlimited if set to 0.
	* @since 4.7
	*/
	public PacketLineIn(InputStream in, long limit) {
	this.in = in;
	this.limit = limit;
	}

	AckNackResult readACK(final MutableObjectId returnedId) throws IOException {
	final String line = readString();
	if (line.length() == 0)
	throw new PackProtocolException(JGitText.get().expectedACKNAKFoundEOF);
	if ("NAK".equals(line)) //$NON-NLS-1$
	return AckNackResult.NAK;
	if (line.startsWith("ACK ")) { //$NON-NLS-1$
	returnedId.fromString(line.substring(4, 44));
	if (line.length() == 44)
	return AckNackResult.ACK;

	final String arg = line.substring(44);
	if (arg.equals(" continue")) //$NON-NLS-1$
	return AckNackResult.ACK_CONTINUE;
	else if (arg.equals(" common")) //$NON-NLS-1$
	return AckNackResult.ACK_COMMON;
	else if (arg.equals(" ready")) //$NON-NLS-1$
	return AckNackResult.ACK_READY;
	}
	if (line.startsWith("ERR ")) //$NON-NLS-1$
	throw new PackProtocolException(line.substring(4));
	throw new PackProtocolException(MessageFormat.format(JGitText.get().expectedACKNAKGot, line));
	}

	/**
	* Read a single UTF-8 encoded string packet from the input stream.
	* <p>
	* If the string ends with an LF, it will be removed before returning the
	* value to the caller. If this automatic trimming behavior is not desired,
	* use {@link #readStringRaw()} instead.
	*
	* @return the string. {@link #END} if the string was the magic flush
	* packet.
	* @throws IOException
	* the stream cannot be read.
	*/
	public String readString() throws IOException {
	int len = readLength();
	if (len == 0) {
	log.debug("git< 0000"); //$NON-NLS-1$
	return END;
	}

	len -= 4; // length header (4 bytes)
	if (len == 0) {
	log.debug("git< "); //$NON-NLS-1$
	return ""; //$NON-NLS-1$
	}

	byte[] raw;
	if (len <= lineBuffer.length)
	raw = lineBuffer;
	else
	raw = new byte[len];

	IO.readFully(in, raw, 0, len);
	if (raw[len - 1] == '\n')
	len--;

	String s = RawParseUtils.decode(Constants.CHARSET, raw, 0, len);
	log.debug("git< " + s); //$NON-NLS-1$
	return s;
	}

	/**
	* Read a single UTF-8 encoded string packet from the input stream.
	* <p>
	* Unlike {@link #readString()} a trailing LF will be retained.
	*
	* @return the string. {@link #END} if the string was the magic flush
	* packet.
	* @throws IOException
	* the stream cannot be read.
	*/
	public String readStringRaw() throws IOException {
	int len = readLength();
	if (len == 0) {
	log.debug("git< 0000"); //$NON-NLS-1$
	return END;
	}

	len -= 4; // length header (4 bytes)

	byte[] raw;
	if (len <= lineBuffer.length)
	raw = lineBuffer;
	else
	raw = new byte[len];

	IO.readFully(in, raw, 0, len);

	String s = RawParseUtils.decode(Constants.CHARSET, raw, 0, len);
	log.debug("git< " + s); //$NON-NLS-1$
	return s;
	}

	void discardUntilEnd() throws IOException {
	for (;;) {
	int n = readLength();
	if (n == 0) {
	break;
	}
	IO.skipFully(in, n - 4);
	}
	}

	int readLength() throws IOException {
	IO.readFully(in, lineBuffer, 0, 4);
	int len;
	try {
	len = RawParseUtils.parseHexInt16(lineBuffer, 0);
	} catch (ArrayIndexOutOfBoundsException err) {
	throw invalidHeader();
	}

	if (len == 0) {
	return 0;
	} else if (len < 4) {
	throw invalidHeader();
	}

	if (limit != 0) {
	int n = len - 4;
	if (limit < n) {
	limit = -1;
	try {
	IO.skipFully(in, n);
	} catch (IOException e) {
	// Ignore failure discarding packet over limit.
	}
	throw new InputOverLimitIOException();
	}
	// if set limit must not be 0 (means unlimited).
	limit = n < limit ? limit - n : -1;
	}
	return len;
	}

	private IOException invalidHeader() {
	return new IOException(MessageFormat.format(JGitText.get().invalidPacketLineHeader,
	"" + (char) lineBuffer[0] + (char) lineBuffer[1] //$NON-NLS-1$
	+ (char) lineBuffer[2] + (char) lineBuffer[3]));
	}

	/**
	* IOException thrown by read when the configured input limit is exceeded.
	*
	* @since 4.7
	*/
	public static class InputOverLimitIOException extends IOException {
	private static final long serialVersionUID = 1L;
	}
	}