org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV2Parser.java - jgit - Git at Google

 /*
  * Copyright (C) 2018, Google LLC.
  * 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 static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_DEEPEN_RELATIVE;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_FILTER;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_AGENT;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_INCLUDE_TAG;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_NO_PROGRESS;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_OFS_DELTA;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SERVER_OPTION;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDE_BAND_64K;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_THIN_PACK;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_WANT_REF;

 import java.io.IOException;
 import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Consumer;

 import org.eclipse.jgit.errors.PackProtocolException;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.ObjectId;

 /**
  * Parse the incoming git protocol lines from the wire and translate them into a
  * Request object.
  *
  * It requires a transferConfig object to know what the server supports (e.g.
  * ref-in-want and/or filters).
  */
 final class ProtocolV2Parser {

 	private final TransferConfig transferConfig;

 	ProtocolV2Parser(TransferConfig transferConfig) {
 		this.transferConfig = transferConfig;
 	}

 	/*
 	 * Read lines until DELIM or END, calling the appropiate consumer.
 	 *
 	 * Returns the last read line (so caller can check if there is more to read
 	 * in the line).
 	 */
 	private static String consumeCapabilities(PacketLineIn pckIn,
 			Consumer<String> serverOptionConsumer,
 			Consumer<String> agentConsumer) throws IOException {

 		String serverOptionPrefix = OPTION_SERVER_OPTION + '=';
 		String agentPrefix = OPTION_AGENT + '=';

 		String line = pckIn.readString();
 		while (line != PacketLineIn.DELIM && line != PacketLineIn.END) {
 			if (line.startsWith(serverOptionPrefix)) {
 				serverOptionConsumer
 						.accept(line.substring(serverOptionPrefix.length()));
 			} else if (line.startsWith(agentPrefix)) {
 				agentConsumer.accept(line.substring(agentPrefix.length()));
 			} else {
 				// Unrecognized capability. Ignore it.
 			}
 			line = pckIn.readString();
 		}

 		return line;
 	}

 	/**
 	 * Parse the incoming fetch request arguments from the wire. The caller must
 	 * be sure that what is comings is a fetch request before coming here.
 	 *
 	 * @param pckIn
 	 *            incoming lines
 	 * @return A FetchV2Request populated with information received from the
 	 *         wire.
 	 * @throws PackProtocolException
 	 *             incompatible options, wrong type of arguments or other issues
 	 *             where the request breaks the protocol.
 	 * @throws IOException
 	 *             an IO error prevented reading the incoming message.
 	 */
 	FetchV2Request parseFetchRequest(PacketLineIn pckIn)
 			throws PackProtocolException, IOException {
 		FetchV2Request.Builder reqBuilder = FetchV2Request.builder();

 		// Packs are always sent multiplexed and using full 64K
 		// lengths.
 		reqBuilder.addClientCapability(OPTION_SIDE_BAND_64K);

 		String line = consumeCapabilities(pckIn,
 				serverOption -> reqBuilder.addServerOption(serverOption),
 				agent -> reqBuilder.setAgent(agent));

 		if (line == PacketLineIn.END) {
 			return reqBuilder.build();
 		}

 		if (line != PacketLineIn.DELIM) {
 			throw new PackProtocolException(
 					MessageFormat.format(JGitText.get().unexpectedPacketLine,
 							line));
 		}

 		boolean filterReceived = false;
 		while ((line = pckIn.readString()) != PacketLineIn.END) {
 			if (line.startsWith("want ")) { //$NON-NLS-1$
 				reqBuilder.addWantId(ObjectId.fromString(line.substring(5)));
 			} else if (transferConfig.isAllowRefInWant()
 					&& line.startsWith(OPTION_WANT_REF + " ")) { //$NON-NLS-1$
 				reqBuilder.addWantedRef(line.substring(OPTION_WANT_REF.length() + 1));
 			} else if (line.startsWith("have ")) { //$NON-NLS-1$
 				reqBuilder.addPeerHas(ObjectId.fromString(line.substring(5)));
 			} else if (line.equals("done")) { //$NON-NLS-1$
 				reqBuilder.setDoneReceived();
 			} else if (line.equals(OPTION_THIN_PACK)) {
 				reqBuilder.addClientCapability(OPTION_THIN_PACK);
 			} else if (line.equals(OPTION_NO_PROGRESS)) {
 				reqBuilder.addClientCapability(OPTION_NO_PROGRESS);
 			} else if (line.equals(OPTION_INCLUDE_TAG)) {
 				reqBuilder.addClientCapability(OPTION_INCLUDE_TAG);
 			} else if (line.equals(OPTION_OFS_DELTA)) {
 				reqBuilder.addClientCapability(OPTION_OFS_DELTA);
 			} else if (line.startsWith("shallow ")) { //$NON-NLS-1$
 				reqBuilder.addClientShallowCommit(
 						ObjectId.fromString(line.substring(8)));
 			} else if (line.startsWith("deepen ")) { //$NON-NLS-1$
 				int parsedDepth = Integer.parseInt(line.substring(7));
 				if (parsedDepth <= 0) {
 					throw new PackProtocolException(
 							MessageFormat.format(JGitText.get().invalidDepth,
 									Integer.valueOf(parsedDepth)));
 				}
 				if (reqBuilder.getDeepenSince() != 0) {
 					throw new PackProtocolException(
 							JGitText.get().deepenSinceWithDeepen);
 				}
 				if (reqBuilder.hasDeepenNotRefs()) {
 					throw new PackProtocolException(
 							JGitText.get().deepenNotWithDeepen);
 				}
 				reqBuilder.setDepth(parsedDepth);
 			} else if (line.startsWith("deepen-not ")) { //$NON-NLS-1$
 				reqBuilder.addDeepenNotRef(line.substring(11));
 				if (reqBuilder.getDepth() != 0) {
 					throw new PackProtocolException(
 							JGitText.get().deepenNotWithDeepen);
 				}
 			} else if (line.equals(OPTION_DEEPEN_RELATIVE)) {
 				reqBuilder.addClientCapability(OPTION_DEEPEN_RELATIVE);
 			} else if (line.startsWith("deepen-since ")) { //$NON-NLS-1$
 				int ts = Integer.parseInt(line.substring(13));
 				if (ts <= 0) {
 					throw new PackProtocolException(MessageFormat
 							.format(JGitText.get().invalidTimestamp, line));
 				}
 				if (reqBuilder.getDepth() != 0) {
 					throw new PackProtocolException(
 							JGitText.get().deepenSinceWithDeepen);
 				}
 				reqBuilder.setDeepenSince(ts);
 			} else if (transferConfig.isAllowFilter()
 					&& line.startsWith(OPTION_FILTER + ' ')) {
 				if (filterReceived) {
 					throw new PackProtocolException(
 							JGitText.get().tooManyFilters);
 				}
 				filterReceived = true;
 				reqBuilder.setFilterBlobLimit(filterLine(
 						line.substring(OPTION_FILTER.length() + 1)));
 			} else {
 				throw new PackProtocolException(MessageFormat
 						.format(JGitText.get().unexpectedPacketLine, line));
 			}
 		}

 		return reqBuilder.build();
 	}

 	/**
 	 * Parse the incoming ls-refs request arguments from the wire. This is meant
 	 * for calling immediately after the caller has consumed a "command=ls-refs"
 	 * line indicating the beginning of a ls-refs request.
 	 *
 	 * The incoming PacketLineIn is consumed until an END line, but the caller
 	 * is responsible for closing it (if needed)
 	 *
 	 * @param pckIn
 	 *            incoming lines. This method will read until an END line.
 	 * @return a LsRefsV2Request object with the data received in the wire.
 	 * @throws PackProtocolException
 	 *             for inconsistencies in the protocol (e.g. unexpected lines)
 	 * @throws IOException
 	 *             reporting problems reading the incoming messages from the
 	 *             wire
 	 */
 	LsRefsV2Request parseLsRefsRequest(PacketLineIn pckIn)
 			throws PackProtocolException, IOException {
 		LsRefsV2Request.Builder builder = LsRefsV2Request.builder();
 		List<String> prefixes = new ArrayList<>();

 		String line = consumeCapabilities(pckIn,
 				serverOption -> builder.addServerOption(serverOption),
 				agent -> builder.setAgent(agent));

 		if (line == PacketLineIn.END) {
 			return builder.build();
 		}

 		if (line != PacketLineIn.DELIM) {
 			throw new PackProtocolException(MessageFormat
 					.format(JGitText.get().unexpectedPacketLine, line));
 		}

 		while ((line = pckIn.readString()) != PacketLineIn.END) {
 			if (line.equals("peel")) { //$NON-NLS-1$
 				builder.setPeel(true);
 			} else if (line.equals("symrefs")) { //$NON-NLS-1$
 				builder.setSymrefs(true);
 			} else if (line.startsWith("ref-prefix ")) { //$NON-NLS-1$
 				prefixes.add(line.substring("ref-prefix ".length())); //$NON-NLS-1$
 			} else {
 				throw new PackProtocolException(MessageFormat
 						.format(JGitText.get().unexpectedPacketLine, line));
 			}
 		}

 		return builder.setRefPrefixes(prefixes).build();
 	}

 	/*
 	 * Process the content of "filter" line from the protocol. It has a shape
 	 * like "blob:none" or "blob:limit=N", with limit a positive number.
 	 *
 	 * @param blobLine
 	 *            the content of the "filter" line in the protocol
 	 * @return N, the limit, defaulting to 0 if "none"
 	 * @throws PackProtocolException
 	 *             invalid filter because due to unrecognized format or
 	 *             negative/non-numeric filter.
 	 */
 	static long filterLine(String blobLine) throws PackProtocolException {
 		long blobLimit = -1;

 		if (blobLine.equals("blob:none")) { //$NON-NLS-1$
 			blobLimit = 0;
 		} else if (blobLine.startsWith("blob:limit=")) { //$NON-NLS-1$
 			try {
 				blobLimit = Long
 						.parseLong(blobLine.substring("blob:limit=".length())); //$NON-NLS-1$
 			} catch (NumberFormatException e) {
 				throw new PackProtocolException(MessageFormat
 						.format(JGitText.get().invalidFilter, blobLine));
 			}
 		}
 		/*
 		 * We must have (1) either "blob:none" or "blob:limit=" set (because we
 		 * only support blob size limits for now), and (2) if the latter, then
 		 * it must be nonnegative. Throw if (1) or (2) is not met.
 		 */
 		if (blobLimit < 0) {
 			throw new PackProtocolException(
 					MessageFormat.format(JGitText.get().invalidFilter, blobLine));
 		}

 		return blobLimit;
 	}

 }
	/*
	* Copyright (C) 2018, Google LLC.
	* 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 static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_DEEPEN_RELATIVE;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_FILTER;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_AGENT;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_INCLUDE_TAG;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_NO_PROGRESS;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_OFS_DELTA;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SERVER_OPTION;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDE_BAND_64K;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_THIN_PACK;
	import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_WANT_REF;

	import java.io.IOException;
	import java.text.MessageFormat;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.function.Consumer;

	import org.eclipse.jgit.errors.PackProtocolException;
	import org.eclipse.jgit.internal.JGitText;
	import org.eclipse.jgit.lib.ObjectId;

	/**
	* Parse the incoming git protocol lines from the wire and translate them into a
	* Request object.
	*
	* It requires a transferConfig object to know what the server supports (e.g.
	* ref-in-want and/or filters).
	*/
	final class ProtocolV2Parser {

	private final TransferConfig transferConfig;

	ProtocolV2Parser(TransferConfig transferConfig) {
	this.transferConfig = transferConfig;
	}

	/*
	* Read lines until DELIM or END, calling the appropiate consumer.
	*
	* Returns the last read line (so caller can check if there is more to read
	* in the line).
	*/
	private static String consumeCapabilities(PacketLineIn pckIn,
	Consumer<String> serverOptionConsumer,
	Consumer<String> agentConsumer) throws IOException {

	String serverOptionPrefix = OPTION_SERVER_OPTION + '=';
	String agentPrefix = OPTION_AGENT + '=';

	String line = pckIn.readString();
	while (line != PacketLineIn.DELIM && line != PacketLineIn.END) {
	if (line.startsWith(serverOptionPrefix)) {
	serverOptionConsumer
	.accept(line.substring(serverOptionPrefix.length()));
	} else if (line.startsWith(agentPrefix)) {
	agentConsumer.accept(line.substring(agentPrefix.length()));
	} else {
	// Unrecognized capability. Ignore it.
	}
	line = pckIn.readString();
	}

	return line;
	}

	/**
	* Parse the incoming fetch request arguments from the wire. The caller must
	* be sure that what is comings is a fetch request before coming here.
	*
	* @param pckIn
	* incoming lines
	* @return A FetchV2Request populated with information received from the
	* wire.
	* @throws PackProtocolException
	* incompatible options, wrong type of arguments or other issues
	* where the request breaks the protocol.
	* @throws IOException
	* an IO error prevented reading the incoming message.
	*/
	FetchV2Request parseFetchRequest(PacketLineIn pckIn)
	throws PackProtocolException, IOException {
	FetchV2Request.Builder reqBuilder = FetchV2Request.builder();

	// Packs are always sent multiplexed and using full 64K
	// lengths.
	reqBuilder.addClientCapability(OPTION_SIDE_BAND_64K);

	String line = consumeCapabilities(pckIn,
	serverOption -> reqBuilder.addServerOption(serverOption),
	agent -> reqBuilder.setAgent(agent));

	if (line == PacketLineIn.END) {
	return reqBuilder.build();
	}

	if (line != PacketLineIn.DELIM) {
	throw new PackProtocolException(
	MessageFormat.format(JGitText.get().unexpectedPacketLine,
	line));
	}

	boolean filterReceived = false;
	while ((line = pckIn.readString()) != PacketLineIn.END) {
	if (line.startsWith("want ")) { //$NON-NLS-1$
	reqBuilder.addWantId(ObjectId.fromString(line.substring(5)));
	} else if (transferConfig.isAllowRefInWant()
	&& line.startsWith(OPTION_WANT_REF + " ")) { //$NON-NLS-1$
	reqBuilder.addWantedRef(line.substring(OPTION_WANT_REF.length() + 1));
	} else if (line.startsWith("have ")) { //$NON-NLS-1$
	reqBuilder.addPeerHas(ObjectId.fromString(line.substring(5)));
	} else if (line.equals("done")) { //$NON-NLS-1$
	reqBuilder.setDoneReceived();
	} else if (line.equals(OPTION_THIN_PACK)) {
	reqBuilder.addClientCapability(OPTION_THIN_PACK);
	} else if (line.equals(OPTION_NO_PROGRESS)) {
	reqBuilder.addClientCapability(OPTION_NO_PROGRESS);
	} else if (line.equals(OPTION_INCLUDE_TAG)) {
	reqBuilder.addClientCapability(OPTION_INCLUDE_TAG);
	} else if (line.equals(OPTION_OFS_DELTA)) {
	reqBuilder.addClientCapability(OPTION_OFS_DELTA);
	} else if (line.startsWith("shallow ")) { //$NON-NLS-1$
	reqBuilder.addClientShallowCommit(
	ObjectId.fromString(line.substring(8)));
	} else if (line.startsWith("deepen ")) { //$NON-NLS-1$
	int parsedDepth = Integer.parseInt(line.substring(7));
	if (parsedDepth <= 0) {
	throw new PackProtocolException(
	MessageFormat.format(JGitText.get().invalidDepth,
	Integer.valueOf(parsedDepth)));
	}
	if (reqBuilder.getDeepenSince() != 0) {
	throw new PackProtocolException(
	JGitText.get().deepenSinceWithDeepen);
	}
	if (reqBuilder.hasDeepenNotRefs()) {
	throw new PackProtocolException(
	JGitText.get().deepenNotWithDeepen);
	}
	reqBuilder.setDepth(parsedDepth);
	} else if (line.startsWith("deepen-not ")) { //$NON-NLS-1$
	reqBuilder.addDeepenNotRef(line.substring(11));
	if (reqBuilder.getDepth() != 0) {
	throw new PackProtocolException(
	JGitText.get().deepenNotWithDeepen);
	}
	} else if (line.equals(OPTION_DEEPEN_RELATIVE)) {
	reqBuilder.addClientCapability(OPTION_DEEPEN_RELATIVE);
	} else if (line.startsWith("deepen-since ")) { //$NON-NLS-1$
	int ts = Integer.parseInt(line.substring(13));
	if (ts <= 0) {
	throw new PackProtocolException(MessageFormat
	.format(JGitText.get().invalidTimestamp, line));
	}
	if (reqBuilder.getDepth() != 0) {
	throw new PackProtocolException(
	JGitText.get().deepenSinceWithDeepen);
	}
	reqBuilder.setDeepenSince(ts);
	} else if (transferConfig.isAllowFilter()
	&& line.startsWith(OPTION_FILTER + ' ')) {
	if (filterReceived) {
	throw new PackProtocolException(
	JGitText.get().tooManyFilters);
	}
	filterReceived = true;
	reqBuilder.setFilterBlobLimit(filterLine(
	line.substring(OPTION_FILTER.length() + 1)));
	} else {
	throw new PackProtocolException(MessageFormat
	.format(JGitText.get().unexpectedPacketLine, line));
	}
	}

	return reqBuilder.build();
	}

	/**
	* Parse the incoming ls-refs request arguments from the wire. This is meant
	* for calling immediately after the caller has consumed a "command=ls-refs"
	* line indicating the beginning of a ls-refs request.
	*
	* The incoming PacketLineIn is consumed until an END line, but the caller
	* is responsible for closing it (if needed)
	*
	* @param pckIn
	* incoming lines. This method will read until an END line.
	* @return a LsRefsV2Request object with the data received in the wire.
	* @throws PackProtocolException
	* for inconsistencies in the protocol (e.g. unexpected lines)
	* @throws IOException
	* reporting problems reading the incoming messages from the
	* wire
	*/
	LsRefsV2Request parseLsRefsRequest(PacketLineIn pckIn)
	throws PackProtocolException, IOException {
	LsRefsV2Request.Builder builder = LsRefsV2Request.builder();
	List<String> prefixes = new ArrayList<>();

	String line = consumeCapabilities(pckIn,
	serverOption -> builder.addServerOption(serverOption),
	agent -> builder.setAgent(agent));

	if (line == PacketLineIn.END) {
	return builder.build();
	}

	if (line != PacketLineIn.DELIM) {
	throw new PackProtocolException(MessageFormat
	.format(JGitText.get().unexpectedPacketLine, line));
	}

	while ((line = pckIn.readString()) != PacketLineIn.END) {
	if (line.equals("peel")) { //$NON-NLS-1$
	builder.setPeel(true);
	} else if (line.equals("symrefs")) { //$NON-NLS-1$
	builder.setSymrefs(true);
	} else if (line.startsWith("ref-prefix ")) { //$NON-NLS-1$
	prefixes.add(line.substring("ref-prefix ".length())); //$NON-NLS-1$
	} else {
	throw new PackProtocolException(MessageFormat
	.format(JGitText.get().unexpectedPacketLine, line));
	}
	}

	return builder.setRefPrefixes(prefixes).build();
	}

	/*
	* Process the content of "filter" line from the protocol. It has a shape
	* like "blob:none" or "blob:limit=N", with limit a positive number.
	*
	* @param blobLine
	* the content of the "filter" line in the protocol
	* @return N, the limit, defaulting to 0 if "none"
	* @throws PackProtocolException
	* invalid filter because due to unrecognized format or
	* negative/non-numeric filter.
	*/
	static long filterLine(String blobLine) throws PackProtocolException {
	long blobLimit = -1;

	if (blobLine.equals("blob:none")) { //$NON-NLS-1$
	blobLimit = 0;
	} else if (blobLine.startsWith("blob:limit=")) { //$NON-NLS-1$
	try {
	blobLimit = Long
	.parseLong(blobLine.substring("blob:limit=".length())); //$NON-NLS-1$
	} catch (NumberFormatException e) {
	throw new PackProtocolException(MessageFormat
	.format(JGitText.get().invalidFilter, blobLine));
	}
	}
	/*
	* We must have (1) either "blob:none" or "blob:limit=" set (because we
	* only support blob size limits for now), and (2) if the latter, then
	* it must be nonnegative. Throw if (1) or (2) is not met.
	*/
	if (blobLimit < 0) {
	throw new PackProtocolException(
	MessageFormat.format(JGitText.get().invalidFilter, blobLine));
	}

	return blobLimit;
	}

	}