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.coordinator.common.runtime;
  
  import org.apache.kafka.common.KafkaException;
  import org.apache.kafka.common.TopicPartition;
  import org.apache.kafka.common.record.MemoryRecords;
  import org.apache.kafka.storage.internals.log.LogConfig;
  import org.apache.kafka.storage.internals.log.VerificationGuard;
  
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.locks.ReentrantLock;
  import java.util.stream.StreamSupport;
  
  /**
   * An in-memory partition writer.
   */
  public class InMemoryPartitionWriter implements PartitionWriter {
  
      private static class PartitionState {
          private final ReentrantLock lock = new ReentrantLock();
          private final List<Listener> listeners = new ArrayList<>();
          private final List<MemoryRecords> entries = new ArrayList<>();
          private long endOffset = 0L;
          private long committedOffset = 0L;
      }
  
      private final boolean autoCommit;
      private final Map<TopicPartition, PartitionState> partitions;
  
      public InMemoryPartitionWriter(boolean autoCommit) {
          this.autoCommit = autoCommit;
          this.partitions = new ConcurrentHashMap<>();
      }
  
      private PartitionState partitionState(
          TopicPartition tp
      ) {
          return partitions.computeIfAbsent(tp, __ -> new PartitionState());
      }
  
      @Override
      public void registerListener(
          TopicPartition tp,
          Listener listener
      ) {
          PartitionState state = partitionState(tp);
          state.lock.lock();
          try {
              state.listeners.add(listener);
          } finally {
              state.lock.unlock();
          }
      }
  
      @Override
      public void deregisterListener(
          TopicPartition tp,
          Listener listener
      ) {
          PartitionState state = partitionState(tp);
          state.lock.lock();
          try {
              state.listeners.remove(listener);
          } finally {
              state.lock.unlock();
          }
      }
  
      @Override
      public LogConfig config(TopicPartition tp) {
          return new LogConfig(Map.of());
      }
  
      @Override
      public long append(
          TopicPartition tp,
          VerificationGuard verificationGuard,
          MemoryRecords batch
      ) {
          PartitionState state = partitionState(tp);
          state.lock.lock();
          try {
              // Copy the memory records because the coordinator runtime reuse the buffer.
              ByteBuffer buffer = ByteBuffer.allocate(batch.sizeInBytes());
              batch.firstBatch().writeTo(buffer);
              buffer.flip();
              state.entries.add(MemoryRecords.readableRecords(buffer));
              // Increment the end offset.
              state.endOffset += StreamSupport.stream(batch.records().spliterator(), false).count();
              if (autoCommit) commit(tp, state.endOffset);
              return state.endOffset;
          } finally {
              state.lock.unlock();
          }
      }
  
      @Override
      public CompletableFuture<Void> deleteRecords(
          TopicPartition tp,
          long deleteBeforeOffset
      ) throws KafkaException {
          throw new RuntimeException("method not implemented");
      }
  
      @Override
      public CompletableFuture<VerificationGuard> maybeStartTransactionVerification(
          TopicPartition tp,
          String transactionalId,
          long producerId,
          short producerEpoch,
          int apiVersion
      ) throws KafkaException {
          return CompletableFuture.completedFuture(new VerificationGuard());
      }
  
      public void commit(
          TopicPartition tp,
          long offset
      ) {
          PartitionState state = partitionState(tp);
          state.lock.lock();
          try {
              state.committedOffset = offset;
              state.listeners.forEach(listener ->
                  listener.onHighWatermarkUpdated(tp, state.committedOffset));
          } finally {
              state.lock.unlock();
          }
      }
  
      public void commit(
          TopicPartition tp
      ) {
          PartitionState state = partitionState(tp);
          state.lock.lock();
          try {
              state.committedOffset = state.endOffset;
              state.listeners.forEach(listener ->
                  listener.onHighWatermarkUpdated(tp, state.committedOffset));
          } finally {
              state.lock.unlock();
          }
      }
  
      public List<MemoryRecords> entries(
          TopicPartition tp
      ) {
          PartitionState state = partitionState(tp);
          state.lock.lock();
          try {
              return Collections.unmodifiableList(state.entries);
          } finally {
              state.lock.unlock();
          }
      }
  }
  