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 java.util.ArrayList;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.TreeMap;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.ByteArrayShufflePosition;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.ShuffleEntry;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.ShuffleEntryReader;
  import org.apache.beam.runners.dataflow.worker.util.common.worker.ShufflePosition;
  import org.apache.beam.sdk.util.common.Reiterator;
  import org.apache.beam.vendor.grpc.v1p69p0.com.google.protobuf.ByteString;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /** A fake implementation of a ShuffleEntryReader, for testing. */
  public class TestShuffleReader implements ShuffleEntryReader {
    // Sorts by secondary key where an empty secondary key sorts before all other secondary keys.
    static final Comparator<ByteString> SHUFFLE_KEY_COMPARATOR =
        (o1, o2) -> {
          if (o1 == o2) {
            return 0;
          }
          if (o1 == null) {
            return -1;
          }
          if (o2 == null) {
            return 1;
          }
          return ByteString.unsignedLexicographicalComparator().compare(o1, o2);
        };
  
    final TreeMap<ByteString, TreeMap<ByteString, List<ShuffleEntry>>> records =
        new TreeMap<>(SHUFFLE_KEY_COMPARATOR);
    boolean closed = false;
  
    public TestShuffleReader() {}
  
    public void addEntry(String key, String secondaryKey, String value) {
      addEntry(
          new ShuffleEntry(
              ByteString.copyFromUtf8(key),
              ByteString.copyFromUtf8(secondaryKey),
              ByteString.copyFromUtf8(value)));
    }
  
    public void addEntry(ShuffleEntry entry) {
      TreeMap<ByteString, List<ShuffleEntry>> valuesBySecondaryKey = records.get(entry.getKey());
      if (valuesBySecondaryKey == null) {
        valuesBySecondaryKey = new TreeMap<>(SHUFFLE_KEY_COMPARATOR);
        records.put(entry.getKey(), valuesBySecondaryKey);
      }
      List<ShuffleEntry> values = valuesBySecondaryKey.get(entry.getSecondaryKey());
      if (values == null) {
        values = new ArrayList<>();
        valuesBySecondaryKey.put(entry.getSecondaryKey(), values);
      }
      values.add(entry);
    }
  
    public Iterator<ShuffleEntry> read() {
      return read((ByteString) null, null);
    }
  
    private ByteString toByteString(ShufflePosition pos) {
      byte[] posBytes = ByteArrayShufflePosition.getPosition(pos);
      if (posBytes == null) {
        return null;
      }
      return ByteString.copyFrom(posBytes);
    }
  
    @Override
    public Reiterator<ShuffleEntry> read(
        @Nullable ShufflePosition startPosition, @Nullable ShufflePosition endPosition) {
      if (closed) {
        throw new RuntimeException("Cannot read from a closed reader.");
      }
      return read(toByteString(startPosition), toByteString(endPosition));
    }
  
    public Reiterator<ShuffleEntry> read(@Nullable String startKey, @Nullable String endKey) {
      return read(
          startKey == null ? null : ByteString.copyFromUtf8(startKey),
          endKey == null ? null : ByteString.copyFromUtf8(endKey));
    }
  
    public Reiterator<ShuffleEntry> read(@Nullable ByteString startKey, @Nullable ByteString endKey) {
      List<ShuffleEntry> res = new ArrayList<>();
      for (ByteString key : records.keySet()) {
        if ((startKey == null || SHUFFLE_KEY_COMPARATOR.compare(startKey, key) <= 0)
            && (endKey == null || SHUFFLE_KEY_COMPARATOR.compare(key, endKey) < 0)) {
          TreeMap<ByteString, List<ShuffleEntry>> entriesBySecondaryKey = records.get(key);
          for (Map.Entry<ByteString, List<ShuffleEntry>> entries : entriesBySecondaryKey.entrySet()) {
            res.addAll(entries.getValue());
          }
        }
      }
      return new ListReiterator<>(res);
    }
  
    @Override
    public void close() {
      closed = true;
    }
  
    public boolean isClosed() {
      return closed;
    }
  
    private static class ListReiterator<T> implements Reiterator<T> {
      private final List<T> items;
      private int lastReturnedIndex = -1;
  
      private ListReiterator(List<T> items) {
        this.items = items;
      }
  
      @Override
      public Reiterator<T> copy() {
        ListReiterator<T> res = new ListReiterator<>(items);
        res.lastReturnedIndex = this.lastReturnedIndex;
        return res;
      }
  
      @Override
      public boolean hasNext() {
        return lastReturnedIndex < items.size() - 1;
      }
  
      @Override
      public T next() {
        if (!hasNext()) {
          throw new NoSuchElementException();
        }
        lastReturnedIndex++;
        return items.get(lastReturnedIndex);
      }
  
      @Override
      public void remove() {
        throw new UnsupportedOperationException();
      }
    }
  }
  