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.cassandra.io.util;
  
  import java.nio.ByteBuffer;
  import java.util.Optional;
  
  public class ChecksummedSequentialWriter extends SequentialWriter
  {
      private static final SequentialWriterOption CRC_WRITER_OPTION = SequentialWriterOption.newBuilder()
                                                                                            .bufferSize(8 * 1024)
                                                                                            .build();
  
      private final SequentialWriter crcWriter;
      private final ChecksumWriter crcMetadata;
      private final Optional<File> digestFile;
  
      public ChecksummedSequentialWriter(File file, File crcPath, File digestFile, SequentialWriterOption option)
      {
          super(file, option);
          crcWriter = new SequentialWriter(crcPath, CRC_WRITER_OPTION);
          crcMetadata = new ChecksumWriter(crcWriter);
          crcMetadata.writeChunkSize(buffer.capacity());
          this.digestFile = Optional.ofNullable(digestFile);
      }
  
      @Override
      protected void flushData()
      {
          super.flushData();
          ByteBuffer toAppend = buffer.duplicate();
          toAppend.position(0);
          toAppend.limit(buffer.position());
          crcMetadata.appendDirect(toAppend, false);
      }
  
      protected class TransactionalProxy extends SequentialWriter.TransactionalProxy
      {
          @Override
          protected Throwable doCommit(Throwable accumulate)
          {
              return super.doCommit(crcWriter.commit(accumulate));
          }
  
          @Override
          protected Throwable doAbort(Throwable accumulate)
          {
              return super.doAbort(crcWriter.abort(accumulate));
          }
  
          @Override
          protected void doPrepare()
          {
              syncInternal();
              digestFile.ifPresent(crcMetadata::writeFullChecksum);
              crcWriter.prepareToCommit();
          }
      }
  
      @Override
      protected SequentialWriter.TransactionalProxy txnProxy()
      {
          return new TransactionalProxy();
      }
  }
  