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.util.common.worker;
  
  import static com.google.api.client.util.Base64.decodeBase64;
  import static com.google.api.client.util.Base64.encodeBase64URLSafeString;
  
  import org.apache.beam.vendor.grpc.v1p69p0.com.google.protobuf.ByteString;
  import org.apache.beam.vendor.grpc.v1p69p0.com.google.protobuf.UnsafeByteOperations;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * Represents a position of a {@code GroupingShuffleReader} as an opaque array of bytes, encoded in
   * a way such that lexicographic ordering of the bytes is consistent with the inherent ordering of
   * {@code GroupingShuffleReader} positions.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class ByteArrayShufflePosition implements Comparable<ShufflePosition>, ShufflePosition {
    private static final ByteString ZERO = ByteString.copyFrom(new byte[] {0});
    private final ByteString position;
  
    public ByteArrayShufflePosition(ByteString position) {
      this.position = position;
    }
  
    public static ByteArrayShufflePosition fromBase64(String position) {
      return ByteArrayShufflePosition.of(decodeBase64(position));
    }
  
    public static ByteArrayShufflePosition of(byte[] position) {
      if (position == null) {
        return null;
      }
      return new ByteArrayShufflePosition(UnsafeByteOperations.unsafeWrap(position));
    }
  
    public static ByteArrayShufflePosition of(ByteString position) {
      if (position == null) {
        return null;
      }
      return new ByteArrayShufflePosition(position);
    }
  
    public static byte[] getPosition(@Nullable ShufflePosition shufflePosition) {
      if (shufflePosition == null) {
        return null;
      }
      Preconditions.checkArgument(shufflePosition instanceof ByteArrayShufflePosition);
      ByteArrayShufflePosition adapter = (ByteArrayShufflePosition) shufflePosition;
      return adapter.getPosition().toByteArray();
    }
  
    public ByteString getPosition() {
      return position;
    }
  
    public String encodeBase64() {
      return encodeBase64URLSafeString(position.toByteArray());
    }
  
    /**
     * Returns the {@link ByteArrayShufflePosition} that immediately follows this one, i.e. there are
     * no possible {@link ByteArrayShufflePosition ByteArrayShufflePositions} between this and its
     * successor.
     */
    public ByteArrayShufflePosition immediateSuccessor() {
      return new ByteArrayShufflePosition(position.concat(ZERO));
    }
  
    @Override
    public boolean equals(@Nullable Object o) {
      if (this == o) {
        return true;
      }
      if (o instanceof ByteArrayShufflePosition) {
        ByteArrayShufflePosition that = (ByteArrayShufflePosition) o;
        return this.position.equals(that.position);
      }
      return false;
    }
  
    @Override
    public int hashCode() {
      return position.hashCode();
    }
  
    @Override
    public String toString() {
      return "ShufflePosition(base64:" + encodeBase64() + ")";
    }
  
    /** May only compare homogenous ByteArrayShufflePosition types. */
    @Override
    public int compareTo(ShufflePosition o) {
      if (this == o) {
        return 0;
      }
      ByteArrayShufflePosition other = (ByteArrayShufflePosition) o;
      return ByteString.unsignedLexicographicalComparator().compare(position, other.position);
    }
  }
  