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.metadata.util;
  
  import org.apache.kafka.common.message.LeaderChangeMessage;
  import org.apache.kafka.common.message.SnapshotFooterRecord;
  import org.apache.kafka.common.message.SnapshotHeaderRecord;
  import org.apache.kafka.common.protocol.ByteBufferAccessor;
  import org.apache.kafka.common.record.ControlRecordType;
  import org.apache.kafka.common.record.FileLogInputStream.FileChannelRecordBatch;
  import org.apache.kafka.common.record.FileRecords;
  import org.apache.kafka.common.record.Record;
  import org.apache.kafka.common.utils.Utils;
  import org.apache.kafka.metadata.MetadataRecordSerde;
  import org.apache.kafka.raft.Batch;
  import org.apache.kafka.server.common.ApiMessageAndVersion;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Objects;
  
  
  /**
   * Reads a log file containing KRaft record batches.
   */
  public final class BatchFileReader implements Iterator<BatchFileReader.BatchAndType>, AutoCloseable {
      private static final Logger log = LoggerFactory.getLogger(BatchFileReader.class);
  
      public static class Builder {
          private String path = null;
  
          public Builder setPath(String path) {
              this.path = Objects.requireNonNull(path);
              return this;
          }
  
          public BatchFileReader build() throws Exception {
              if (path == null) {
                  throw new RuntimeException("You must specify a path.");
              }
              FileRecords fileRecords = FileRecords.open(new File(path), false);
              try {
                  return new BatchFileReader(fileRecords);
              } catch (Throwable e) {
                  Utils.closeQuietly(fileRecords, "fileRecords");
                  throw e;
              }
          }
      }
  
      public static class BatchAndType {
          private final Batch<ApiMessageAndVersion> batch;
          private final boolean isControl;
  
          public BatchAndType(Batch<ApiMessageAndVersion> batch, boolean isControl) {
              this.batch = batch;
              this.isControl = isControl;
          }
  
          public Batch<ApiMessageAndVersion> batch() {
              return batch;
          }
  
          public boolean isControl() {
              return isControl;
          }
      }
  
      private final FileRecords fileRecords;
      private Iterator<FileChannelRecordBatch> batchIterator;
      private final MetadataRecordSerde serde;
  
      private BatchFileReader(FileRecords fileRecords) {
          this.fileRecords = fileRecords;
          this.batchIterator = fileRecords.batchIterator();
          this.serde = new MetadataRecordSerde();
      }
  
      @Override
      public boolean hasNext() {
          return this.batchIterator.hasNext();
      }
  
      @Override
      public BatchAndType next() {
          FileChannelRecordBatch input = batchIterator.next();
          if (input.isControlBatch()) {
              return nextControlBatch(input);
          } else {
              return nextDataBatch(input);
          }
      }
  
      private BatchAndType nextControlBatch(FileChannelRecordBatch input) {
          List<ApiMessageAndVersion> messages = new ArrayList<>();
          for (Record record : input) {
              try {
                  short typeId = ControlRecordType.parseTypeId(record.key());
                  ControlRecordType type = ControlRecordType.fromTypeId(typeId);
                  switch (type) {
                      case LEADER_CHANGE: {
                          LeaderChangeMessage message = new LeaderChangeMessage();
                          message.read(new ByteBufferAccessor(record.value()), (short) 0);
                          messages.add(new ApiMessageAndVersion(message, (short) 0));
                          break;
                      }
                      case SNAPSHOT_HEADER: {
                          SnapshotHeaderRecord message = new SnapshotHeaderRecord();
                          message.read(new ByteBufferAccessor(record.value()), (short) 0);
                          messages.add(new ApiMessageAndVersion(message, (short) 0));
                          break;
                      }
                      case SNAPSHOT_FOOTER: {
                          SnapshotFooterRecord message = new SnapshotFooterRecord();
                          message.read(new ByteBufferAccessor(record.value()), (short) 0);
                          messages.add(new ApiMessageAndVersion(message, (short) 0));
                          break;
                      }
                      default:
                          throw new RuntimeException("Unsupported control record type " + type + " at offset " +
                                  record.offset());
                  }
              } catch (Throwable e) {
                  throw new RuntimeException("Unable to read control record at offset " + record.offset(), e);
              }
          }
          return new BatchAndType(Batch.data(
              input.baseOffset(),
              input.partitionLeaderEpoch(),
              input.maxTimestamp(),
              input.sizeInBytes(),
              messages), true);
      }
  
      private BatchAndType nextDataBatch(FileChannelRecordBatch input) {
          List<ApiMessageAndVersion> messages = new ArrayList<>();
          for (Record record : input) {
              try {
                  ByteBufferAccessor accessor = new ByteBufferAccessor(record.value());
                  ApiMessageAndVersion messageAndVersion = serde.read(accessor, record.valueSize());
                  messages.add(messageAndVersion);
              } catch (Throwable e) {
                  throw new RuntimeException("unable to deserialize record at offset " + record.offset(), e);
              }
          }
          return new BatchAndType(Batch.data(
              input.baseOffset(),
              input.partitionLeaderEpoch(),
              input.maxTimestamp(),
              input.sizeInBytes(),
              messages), false);
      }
  
      @Override
      public void close() {
          try {
              fileRecords.closeHandlers();
          } catch (Exception e) {
              log.error("Error closing fileRecords", e);
          }
          this.batchIterator = Collections.emptyIterator();
      }
  }
  