content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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 org.apache.kafka.streams.processor.internals;
  
  import org.apache.kafka.clients.consumer.ConsumerRecord;
  import org.apache.kafka.common.header.Header;
  import org.apache.kafka.common.header.internals.RecordHeader;
  import org.apache.kafka.streams.errors.StreamsException;
  import org.apache.kafka.streams.query.Position;
  import org.apache.kafka.streams.state.internals.PositionSerde;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.nio.ByteBuffer;
  
  /**
   * Changelog records without any headers are considered old format.
   * New format changelog records will have a version in their headers.
   * Version 0: This indicates that the changelog records have consistency information.
   */
  public class ChangelogRecordDeserializationHelper {
      public static final Logger log = LoggerFactory.getLogger(ChangelogRecordDeserializationHelper.class);
      private static final byte[] V_0_CHANGELOG_VERSION_HEADER_VALUE = {(byte) 0};
      public static final String CHANGELOG_VERSION_HEADER_KEY = "v";
      public static final String CHANGELOG_POSITION_HEADER_KEY = "c";
      public static final RecordHeader CHANGELOG_VERSION_HEADER_RECORD_CONSISTENCY = new RecordHeader(
              CHANGELOG_VERSION_HEADER_KEY, V_0_CHANGELOG_VERSION_HEADER_VALUE);
  
      public static void applyChecksAndUpdatePosition(
              final ConsumerRecord<byte[], byte[]> record,
              final boolean consistencyEnabled,
              final Position position
      ) {
          if (!consistencyEnabled) {
              return;
          }
          final Header versionHeader = record.headers().lastHeader(
                  ChangelogRecordDeserializationHelper.CHANGELOG_VERSION_HEADER_KEY);
          if (versionHeader == null) {
              return;
          } else {
              switch (versionHeader.value()[0]) {
                  case 0:
                      final Header vectorHeader = record.headers().lastHeader(CHANGELOG_POSITION_HEADER_KEY);
                      if (vectorHeader == null) {
                          throw new StreamsException("This should not happen. Consistency is enabled but the changelog "
                                  + "contains records without consistency information.");
                      }
                      position.merge(PositionSerde.deserialize(ByteBuffer.wrap(vectorHeader.value())));
                      break;
                  default:
                      log.warn("Changelog records have been encoded using a larger version than this server understands." +
                              "Please upgrade your server.");
              }
          }
      }
  
  
  }
  