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.sasi.conf.view;
  
  import java.nio.ByteBuffer;
  import java.util.*;
  import java.util.stream.Collectors;
  
  import org.apache.cassandra.index.sasi.SSTableIndex;
  import org.apache.cassandra.index.sasi.conf.ColumnIndex;
  import org.apache.cassandra.index.sasi.plan.Expression;
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.db.marshal.AsciiType;
  import org.apache.cassandra.db.marshal.UTF8Type;
  import org.apache.cassandra.io.sstable.Descriptor;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  import org.apache.cassandra.utils.Interval;
  import org.apache.cassandra.utils.IntervalTree;
  
  import com.google.common.collect.Iterables;
  
  public class View implements Iterable<SSTableIndex>
  {
      private final Map<Descriptor, SSTableIndex> view;
  
      private final TermTree termTree;
      private final AbstractType<?> keyValidator;
      private final IntervalTree<Key, SSTableIndex, Interval<Key, SSTableIndex>> keyIntervalTree;
  
      public View(ColumnIndex index, Set<SSTableIndex> indexes)
      {
          this(index, Collections.<SSTableIndex>emptyList(), Collections.<SSTableReader>emptyList(), indexes);
      }
  
      public View(ColumnIndex index,
                  Collection<SSTableIndex> currentView,
                  Collection<SSTableReader> oldSSTables,
                  Set<SSTableIndex> newIndexes)
      {
          Map<Descriptor, SSTableIndex> newView = new HashMap<>();
  
          AbstractType<?> validator = index.getValidator();
          TermTree.Builder termTreeBuilder = (validator instanceof AsciiType || validator instanceof UTF8Type)
                                              ? new PrefixTermTree.Builder(index.getMode().mode, validator)
                                              : new RangeTermTree.Builder(index.getMode().mode, validator);
  
          List<Interval<Key, SSTableIndex>> keyIntervals = new ArrayList<>();
          // Ensure oldSSTables and newIndexes are disjoint (in index redistribution case the intersection can be non-empty).
          // also favor newIndexes over currentView in case an SSTable has been re-opened (also occurs during redistribution)
          // See CASSANDRA-14055
          Collection<SSTableReader> toRemove = new HashSet<>(oldSSTables);
          toRemove.removeAll(newIndexes.stream().map(SSTableIndex::getSSTable).collect(Collectors.toSet()));
          for (SSTableIndex sstableIndex : Iterables.concat(newIndexes, currentView))
          {
              SSTableReader sstable = sstableIndex.getSSTable();
              if (toRemove.contains(sstable) || sstable.isMarkedCompacted() || newView.containsKey(sstable.descriptor))
              {
                  sstableIndex.release();
                  continue;
              }
  
              newView.put(sstable.descriptor, sstableIndex);
  
              termTreeBuilder.add(sstableIndex);
              keyIntervals.add(Interval.create(new Key(sstableIndex.minKey(), index.keyValidator()),
                                               new Key(sstableIndex.maxKey(), index.keyValidator()),
                                               sstableIndex));
          }
  
          this.view = newView;
          this.termTree = termTreeBuilder.build();
          this.keyValidator = index.keyValidator();
          this.keyIntervalTree = IntervalTree.build(keyIntervals);
  
          if (keyIntervalTree.intervalCount() != termTree.intervalCount())
              throw new IllegalStateException(String.format("mismatched sizes for intervals tree for keys vs terms: %d != %d", keyIntervalTree.intervalCount(), termTree.intervalCount()));
      }
  
      public Set<SSTableIndex> match(Expression expression)
      {
          return termTree.search(expression);
      }
  
      public List<SSTableIndex> match(ByteBuffer minKey, ByteBuffer maxKey)
      {
          return keyIntervalTree.search(Interval.create(new Key(minKey, keyValidator), new Key(maxKey, keyValidator), (SSTableIndex) null));
      }
  
      public Iterator<SSTableIndex> iterator()
      {
          return view.values().iterator();
      }
  
      public Collection<SSTableIndex> getIndexes()
      {
          return view.values();
      }
  
      /**
       * This is required since IntervalTree doesn't support custom Comparator
       * implementations and relied on items to be comparable which "raw" keys are not.
       */
      private static class Key implements Comparable<Key>
      {
          private final ByteBuffer key;
          private final AbstractType<?> comparator;
  
          public Key(ByteBuffer key, AbstractType<?> comparator)
          {
              this.key = key;
              this.comparator = comparator;
          }
  
          public int compareTo(Key o)
          {
              return comparator.compare(key, o.key);
          }
      }
  }
  