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.index.sai.disk;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.db.PartitionPosition;
  import org.apache.cassandra.dht.AbstractBounds;
  import org.apache.cassandra.exceptions.QueryCancelledException;
  import org.apache.cassandra.index.sai.QueryContext;
  import org.apache.cassandra.index.sai.memory.MemtableIndex;
  import org.apache.cassandra.index.sai.plan.Expression;
  import org.apache.cassandra.index.sai.iterators.KeyRangeIterator;
  import org.apache.cassandra.index.sai.iterators.KeyRangeUnionIterator;
  import org.apache.cassandra.index.sai.plan.QueryViewBuilder;
  import org.apache.cassandra.index.sai.utils.PrimaryKey;
  import org.apache.cassandra.io.util.FileUtils;
  import org.apache.cassandra.utils.Throwables;
  
  public class IndexSearchResultIterator extends KeyRangeIterator
  {
      private static final Logger logger = LoggerFactory.getLogger(IndexSearchResultIterator.class);
  
      private final KeyRangeIterator union;
  
      private IndexSearchResultIterator(KeyRangeIterator union, Runnable onClose)
      {
          super(union.getMinimum(), union.getMaximum(), union.getMaxKeys(), onClose);
          this.union = union;
      }
  
      /**
       * Builds a new {@link IndexSearchResultIterator} that wraps a {@link KeyRangeUnionIterator} over the
       * results of searching the {@link QueryViewBuilder.QueryExpressionView}.
       */
      public static IndexSearchResultIterator build(QueryViewBuilder.QueryExpressionView queryView,
                                                    AbstractBounds<PartitionPosition> keyRange,
                                                    QueryContext queryContext,
                                                    boolean includeMemtables,
                                                    Runnable onClose)
      {
          return build(queryView.expression, queryView.memtableIndexes, queryView.sstableIndexes, keyRange, queryContext, includeMemtables, onClose);
      }
  
      /**
       * Builds a new {@link IndexSearchResultIterator} that wraps a {@link KeyRangeUnionIterator} over the
       * results of searching the {@link org.apache.cassandra.index.sai.memory.MemtableIndex}es and the {@link SSTableIndex}es.
       */
      public static IndexSearchResultIterator build(Expression expression,
                                                    Collection<MemtableIndex> memtableIndexes,
                                                    Collection<SSTableIndex> sstableIndexes,
                                                    AbstractBounds<PartitionPosition> keyRange,
                                                    QueryContext queryContext,
                                                    boolean includeMemtables,
                                                    Runnable onClose)
      {
          int size = sstableIndexes.size() + (includeMemtables ? memtableIndexes.size() : 0);
          List<KeyRangeIterator> subIterators = new ArrayList<>(size);
  
          if (includeMemtables)
          {
              for (MemtableIndex memtableIndex : memtableIndexes)
              {
                  KeyRangeIterator memtableIterator = memtableIndex.search(queryContext, expression, keyRange);
                  subIterators.add(memtableIterator);
              }
          }
  
          for (SSTableIndex sstableIndex : sstableIndexes)
          {
              try
              {
                  queryContext.checkpoint();
                  queryContext.sstablesHit++;
  
                  if (sstableIndex.isReleased())
                      throw new IllegalStateException(sstableIndex.getIndexIdentifier().logMessage("Index was released from the view during the query"));
  
                  List<KeyRangeIterator> indexIterators = sstableIndex.search(expression, keyRange, queryContext);
  
                  if (!indexIterators.isEmpty())
                      subIterators.addAll(indexIterators);
              }
              catch (Throwable e)
              {
                  if (!(e instanceof QueryCancelledException))
                      logger.debug(sstableIndex.getIndexIdentifier().logMessage(String.format("Failed search an index %s, aborting query.", sstableIndex.getSSTable())), e);
  
                  throw Throwables.cleaned(e);
              }
          }
  
          KeyRangeIterator union = KeyRangeUnionIterator.build(subIterators, () -> {});
          return new IndexSearchResultIterator(union, onClose);
      }
  
      public static IndexSearchResultIterator build(List<KeyRangeIterator> sstableIntersections,
                                                    List<KeyRangeIterator> memtableResults,
                                                    Set<SSTableIndex> referencedIndexes,
                                                    QueryContext queryContext,
                                                    Runnable onClose)
      {
          queryContext.sstablesHit += referencedIndexes
                                      .stream()
                                      .map(SSTableIndex::getSSTable).collect(Collectors.toSet()).size();
          queryContext.checkpoint();
          KeyRangeIterator union = KeyRangeUnionIterator.builder(sstableIntersections.size() + 1, () -> {})
                                                        .add(sstableIntersections)
                                                        .add(memtableResults)
                                                        .build();
          return new IndexSearchResultIterator(union, onClose);
      }
  
      protected PrimaryKey computeNext()
      {
          return union.hasNext() ? union.next() : endOfData();
      }
  
      protected void performSkipTo(PrimaryKey nextKey)
      {
          union.skipTo(nextKey);
      }
  
      @Override
      public void close()
      {
          super.close();
          FileUtils.closeQuietly(union);
      }
  }
  