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.beam.runners.dataflow.worker;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkArgument;
  
  import com.google.api.services.dataflow.model.ApproximateReportedProgress;
  import com.google.api.services.dataflow.model.ApproximateSplitRequest;
  import com.google.api.services.dataflow.model.ReportedParallelism;
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.NoSuchElementException;
  import java.util.Optional;
  import org.apache.avro.Schema;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.NativeReader;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.extensions.avro.io.AvroSource;
  import org.apache.beam.sdk.extensions.avro.io.AvroSource.AvroReader;
  import org.apache.beam.sdk.io.BoundedSource;
  import org.apache.beam.sdk.io.FileSystems;
  import org.apache.beam.sdk.io.OffsetBasedSource;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.util.CoderUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A source that reads PCollections that have been materialized as Avro files. Records are read from
   * the Avro file as a series of byte arrays. The coder provided is used to deserialize each record
   * from a byte array.
   *
   * @param <T> the type of the elements read from the source
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class AvroByteReader<T> extends NativeReader<T> {
    private static final Logger LOG = LoggerFactory.getLogger(AvroByteReader.class);
  
    final long startPosition;
    final long endPosition;
    final String filename;
    final AvroSource<ByteBuffer> avroSource;
    final PipelineOptions options;
  
    final Coder<T> coder;
    private final Schema schema = Schema.create(Schema.Type.BYTES);
  
    AvroByteReader(
        String filename,
        long startPosition,
        long endPosition,
        Coder<T> coder,
        PipelineOptions options) {
      checkArgument(filename != null, "filename must not be null");
      checkArgument(coder != null, "coder must not be null");
      checkArgument(options != null, "options must not be null");
      this.filename = filename;
      this.startPosition = startPosition;
      this.endPosition = endPosition;
      this.coder = coder;
      this.options = options;
      this.avroSource =
          (AvroSource<ByteBuffer>) ((AvroSource) AvroSource.from(filename).withSchema(schema));
    }
  
    @Override
    public AvroByteFileIterator iterator() throws IOException {
      BoundedSource.BoundedReader<ByteBuffer> reader;
      if (startPosition == 0 && endPosition == Long.MAX_VALUE) {
        // Read entire file (or collection of files).
        reader = avroSource.createReader(options);
      } else {
        // Read a subrange of file.
        reader =
            avroSource
                .createForSubrangeOfFile(
                    FileSystems.matchSingleFileSpec(filename), startPosition, endPosition)
                .createReader(options);
      }
      return new AvroByteFileIterator((AvroReader<ByteBuffer>) reader);
    }
  
    class AvroByteFileIterator extends NativeReaderIterator<T> {
      private final AvroReader<ByteBuffer> reader;
      private Optional<T> current;
  
      public AvroByteFileIterator(AvroReader<ByteBuffer> reader) {
        this.reader = reader;
      }
  
      @Override
      public boolean start() throws IOException {
        if (!reader.start()) {
          current = Optional.empty();
          return false;
        }
        updateCurrent();
        return true;
      }
  
      @Override
      public boolean advance() throws IOException {
        if (!reader.advance()) {
          current = Optional.empty();
          return false;
        }
        updateCurrent();
        return true;
      }
  
      private void updateCurrent() throws IOException {
        ByteBuffer inBuffer = reader.getCurrent();
        notifyElementRead(inBuffer.remaining());
        byte[] encodedElem = new byte[inBuffer.remaining()];
        inBuffer.get(encodedElem);
        current = Optional.of(CoderUtils.decodeFromByteArray(coder, encodedElem));
      }
  
      @Override
      public T getCurrent() throws NoSuchElementException {
        return current.get();
      }
  
      @Override
      public Progress getProgress() {
        Double readerProgress = reader.getFractionConsumed();
        if (readerProgress == null) {
          return null;
        }
        ApproximateReportedProgress progress = new ApproximateReportedProgress();
        progress.setFractionConsumed(readerProgress);
        double consumedParallelism = reader.getSplitPointsConsumed();
        double remainingParallelism = reader.getSplitPointsRemaining();
        progress.setConsumedParallelism(new ReportedParallelism().setValue(consumedParallelism));
        if (remainingParallelism >= 0) {
          progress.setRemainingParallelism(new ReportedParallelism().setValue(remainingParallelism));
        }
        return SourceTranslationUtils.cloudProgressToReaderProgress(progress);
      }
  
      @Override
      public void close() throws IOException {
        reader.close();
      }
  
      @Override
      public DynamicSplitResult requestDynamicSplit(DynamicSplitRequest splitRequest) {
        ApproximateSplitRequest splitProgress =
            SourceTranslationUtils.splitRequestToApproximateSplitRequest(splitRequest);
        double splitAtFraction = splitProgress.getFractionConsumed();
        LOG.info("Received request for dynamic split at {}", splitAtFraction);
        OffsetBasedSource<ByteBuffer> residual = reader.splitAtFraction(splitAtFraction);
        if (residual == null) {
          LOG.info("Rejected split request for split at {}", splitAtFraction);
          return null;
        }
        com.google.api.services.dataflow.model.Position acceptedPosition =
            new com.google.api.services.dataflow.model.Position();
        acceptedPosition.setByteOffset(residual.getStartOffset());
        LOG.info(
            "Accepted split for position {} which resulted in a new source with byte offset {}",
            splitAtFraction,
            residual.getStartOffset());
        return new DynamicSplitResultWithPosition(
            SourceTranslationUtils.cloudPositionToReaderPosition(acceptedPosition));
      }
    }
  }
  