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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2019 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.handler.codec.dns;

import io.netty.buffer.ByteBuf;
import io.netty.handler.codec.CorruptedFrameException;

import java.net.SocketAddress;

import static io.netty.util.internal.ObjectUtil.checkNotNull;

abstract class DnsResponseDecoder {

    private final DnsRecordDecoder recordDecoder;

    /**
     * Creates a new decoder with the specified {@code recordDecoder}.
     */
    DnsResponseDecoder(DnsRecordDecoder recordDecoder) {
        this.recordDecoder = checkNotNull(recordDecoder, "recordDecoder");
    }

    final DnsResponse decode(A sender, A recipient, ByteBuf buffer) throws Exception {
        final int id = buffer.readUnsignedShort();

        final int flags = buffer.readUnsignedShort();
        if (flags >> 15 == 0) {
            throw new CorruptedFrameException("not a response");
        }

        final DnsResponse response = newResponse(
                sender,
                recipient,
                id,
                DnsOpCode.valueOf((byte) (flags >> 11 & 0xf)), DnsResponseCode.valueOf((byte) (flags & 0xf)));

        response.setRecursionDesired((flags >> 8 & 1) == 1);
        response.setAuthoritativeAnswer((flags >> 10 & 1) == 1);
        response.setTruncated((flags >> 9 & 1) == 1);
        response.setRecursionAvailable((flags >> 7 & 1) == 1);
        response.setZ(flags >> 4 & 0x7);

        boolean success = false;
        try {
            final int questionCount = buffer.readUnsignedShort();
            final int answerCount = buffer.readUnsignedShort();
            final int authorityRecordCount = buffer.readUnsignedShort();
            final int additionalRecordCount = buffer.readUnsignedShort();

            decodeQuestions(response, buffer, questionCount);
            if (!decodeRecords(response, DnsSection.ANSWER, buffer, answerCount)) {
                success = true;
                return response;
            }
            if (!decodeRecords(response, DnsSection.AUTHORITY, buffer, authorityRecordCount)) {
                success = true;
                return response;
            }

            decodeRecords(response, DnsSection.ADDITIONAL, buffer, additionalRecordCount);
            success = true;
            return response;
        } finally {
            if (!success) {
                response.release();
            }
        }
    }

    protected abstract DnsResponse newResponse(A sender, A recipient, int id,
                                               DnsOpCode opCode, DnsResponseCode responseCode) throws Exception;

    private void decodeQuestions(DnsResponse response, ByteBuf buf, int questionCount) throws Exception {
        for (int i = questionCount; i > 0; i --) {
            response.addRecord(DnsSection.QUESTION, recordDecoder.decodeQuestion(buf));
        }
    }

    private boolean decodeRecords(
            DnsResponse response, DnsSection section, ByteBuf buf, int count) throws Exception {
        for (int i = count; i > 0; i --) {
            final DnsRecord r = recordDecoder.decodeRecord(buf);
            if (r == null) {
                // Truncated response
                return false;
            }

            response.addRecord(section, r);
        }
        return true;
    }
}