ProtocolV0Parser.java

/*
 * 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 {@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).
     *
     * @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();
    }

}