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.common.record;
  
  import org.apache.kafka.common.InvalidRecordException;
  import org.apache.kafka.common.protocol.types.Field;
  import org.apache.kafka.common.protocol.types.Schema;
  import org.apache.kafka.common.protocol.types.Struct;
  import org.apache.kafka.common.protocol.types.Type;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.nio.ByteBuffer;
  
  /**
   * Control records specify a schema for the record key which includes a version and type:
   *
   * Key => Version Type
   *   Version => Int16
   *   Type => Int16
   *
   * In the future, the version can be bumped to indicate a new schema, but it must be backwards compatible
   * with the current schema. In general, this means we can add new fields, but we cannot remove old ones.
   *
   * Note that control records are not considered for compaction by the log cleaner.
   *
   * The schema for the value field is left to the control record type to specify.
   */
  public enum ControlRecordType {
      ABORT((short) 0),
      COMMIT((short) 1),
  
      // KRaft quorum related control messages
      LEADER_CHANGE((short) 2),
      SNAPSHOT_HEADER((short) 3),
      SNAPSHOT_FOOTER((short) 4),
  
      // KRaft membership changes messages
      KRAFT_VERSION((short) 5),
      KRAFT_VOTERS((short) 6),
  
      // UNKNOWN is used to indicate a control type which the client is not aware of and should be ignored
      UNKNOWN((short) -1);
  
      private static final Logger log = LoggerFactory.getLogger(ControlRecordType.class);
  
      static final short CURRENT_CONTROL_RECORD_KEY_VERSION = 0;
      static final int CURRENT_CONTROL_RECORD_KEY_SIZE = 4;
      private static final Schema CONTROL_RECORD_KEY_SCHEMA_VERSION_V0 = new Schema(
              new Field("version", Type.INT16),
              new Field("type", Type.INT16));
  
      private final short type;
  
      ControlRecordType(short type) {
          this.type = type;
      }
  
      public short type() {
          return type;
      }
  
      public Struct recordKey() {
          if (this == UNKNOWN)
              throw new IllegalArgumentException("Cannot serialize UNKNOWN control record type");
  
          Struct struct = new Struct(CONTROL_RECORD_KEY_SCHEMA_VERSION_V0);
          struct.set("version", CURRENT_CONTROL_RECORD_KEY_VERSION);
          struct.set("type", type);
          return struct;
      }
  
      public static short parseTypeId(ByteBuffer key) {
          if (key.remaining() < CURRENT_CONTROL_RECORD_KEY_SIZE)
              throw new InvalidRecordException("Invalid value size found for end control record key. Must have " +
                      "at least " + CURRENT_CONTROL_RECORD_KEY_SIZE + " bytes, but found only " + key.remaining());
  
          short version = key.getShort(0);
          if (version < 0)
              throw new InvalidRecordException("Invalid version found for control record: " + version +
                      ". May indicate data corruption");
  
          if (version != CURRENT_CONTROL_RECORD_KEY_VERSION)
              log.debug("Received unknown control record key version {}. Parsing as version {}", version,
                      CURRENT_CONTROL_RECORD_KEY_VERSION);
          return key.getShort(2);
      }
  
      public static ControlRecordType fromTypeId(short typeId) {
          switch (typeId) {
              case 0:
                  return ABORT;
              case 1:
                  return COMMIT;
              case 2:
                  return LEADER_CHANGE;
              case 3:
                  return SNAPSHOT_HEADER;
              case 4:
                  return SNAPSHOT_FOOTER;
              case 5:
                  return KRAFT_VERSION;
              case 6:
                  return KRAFT_VOTERS;
  
              default:
                  return UNKNOWN;
          }
      }
  
      public static ControlRecordType parse(ByteBuffer key) {
          return fromTypeId(parseTypeId(key));
      }
  }
  