/*
 * Copyright (C) 2018, Google LLC. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package org.eclipse.jgit.transport;

import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_FILTER;

import java.io.EOFException;
import java.io.IOException;
import java.text.MessageFormat;

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

Parser for git protocol versions 0 and 1. It reads the lines coming through the PacketLineIn and builds a FetchV0Request object. It requires a transferConfig object to know if the server supports filters. /**
 * Parser for git protocol versions 0 and 1.
 *
 * It reads the lines coming through the {@link PacketLineIn} and builds a
 * {@link FetchV0Request} object.
 *
 * It requires a transferConfig object to know if the server supports filters.
 */
final class ProtocolV0Parser {

	private final TransferConfig transferConfig;

	ProtocolV0Parser(TransferConfig transferConfig) {
		this.transferConfig = transferConfig;
	}

	
Parse an incoming protocol v1 upload request arguments from the wire.
The incoming PacketLineIn is consumed until an END line, but the caller
is responsible for closing it (if needed).
Params:
pckIn – 
           incoming lines. This method will read until an END line.
Throws:
PackProtocolException – 
IOException – 
Returns:
a FetchV0Request with the data received in the wire./**
	 * Parse an incoming protocol v1 upload request arguments from the wire.
	 *
	 * 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 FetchV0Request with the data received in the wire.
	 * @throws PackProtocolException
	 * @throws IOException
	 */
	FetchV0Request recvWants(PacketLineIn pckIn)
			throws PackProtocolException, IOException {
		FetchV0Request.Builder reqBuilder = new FetchV0Request.Builder();

		boolean isFirst = true;
		boolean filterReceived = false;

		for (;;) {
			String line;
			try {
				line = pckIn.readString();
			} catch (EOFException eof) {
				if (isFirst) {
					break;
				}
				throw eof;
			}

			if (PacketLineIn.isEnd(line)) {
				break;
			}

			if (line.startsWith("deepen ")) { //$NON-NLS-1$
				int depth = Integer.parseInt(line.substring(7));
				if (depth <= 0) {
					throw new PackProtocolException(
							MessageFormat.format(JGitText.get().invalidDepth,
									Integer.valueOf(depth)));
				}
				reqBuilder.setDepth(depth);
				continue;
			}

			if (line.startsWith("shallow ")) { //$NON-NLS-1$
				reqBuilder.addClientShallowCommit(
						ObjectId.fromString(line.substring(8)));
				continue;
			}

			if (transferConfig.isAllowFilter()
					&& line.startsWith(OPTION_FILTER + " ")) { //$NON-NLS-1$
				String arg = line.substring(OPTION_FILTER.length() + 1);

				if (filterReceived) {
					throw new PackProtocolException(
							JGitText.get().tooManyFilters);
				}
				filterReceived = true;

				reqBuilder.setFilterSpec(FilterSpec.fromFilterLine(arg));
				continue;
			}

			if (!line.startsWith("want ") || line.length() < 45) { //$NON-NLS-1$
				throw new PackProtocolException(MessageFormat
						.format(JGitText.get().expectedGot, "want", line)); //$NON-NLS-1$
			}

			if (isFirst) {
				if (line.length() > 45) {
					FirstWant firstLine = FirstWant.fromLine(line);
					reqBuilder.addClientCapabilities(firstLine.getCapabilities());
					reqBuilder.setAgent(firstLine.getAgent());
					line = firstLine.getLine();
				}
			}

			reqBuilder.addWantId(ObjectId.fromString(line.substring(5)));
			isFirst = false;
		}

		return reqBuilder.build();
	}

}