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.repair.asymmetric;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.collect.Sets;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.dht.Range;
  import org.apache.cassandra.dht.RingPosition;
  import org.apache.cassandra.dht.Token;
  
  public class RangeDenormalizer
  {
      private static final Logger logger = LoggerFactory.getLogger(RangeDenormalizer.class);
  
      /**
       * "Denormalizes" (kind of the opposite of what Range.normalize does) the ranges in the keys of {{incoming}}
       *
       * It makes sure that if there is an intersection between {{range}} and some of the ranges in {{incoming.keySet()}}
       * we know that all intersections are keys in the updated {{incoming}}
       */
      public static Set<Range<Token>> denormalize(Range<Token> range, RangeMap<StreamFromOptions> incoming)
      {
          logger.trace("Denormalizing range={} incoming={}", range, incoming);
          Set<Map.Entry<Range<Token>, StreamFromOptions>> existingOverlappingRanges = incoming.removeIntersecting(range);
  
          Set<Range<Token>> intersections = intersection(existingOverlappingRanges, range);
          Set<Range<Token>> newExisting = Sets.union(subtractFromAllRanges(existingOverlappingRanges, range), intersections);
          Set<Range<Token>> newInput = Sets.union(subtractAll(existingOverlappingRanges, range), intersections);
          for (Range<Token> r : newExisting)
          {
              for (Map.Entry<Range<Token>, StreamFromOptions> entry : existingOverlappingRanges)
              {
                  if (r.intersects(entry.getKey()))
                      incoming.put(r, entry.getValue().copy(r));
              }
          }
          if (logger.isTraceEnabled())
          {
              logger.trace("denormalized {} to {}", range, newInput);
              logger.trace("denormalized incoming to {}", incoming);
          }
          return newInput;
      }
  
      /**
       * Subtract the given range from all the input ranges.
       *
       * for example:
       * ranges = [(0, 10], (20, 30]]
       * and range = (8, 22]
       *
       * the result should be [(0, 8], (22, 30]]
       *
       */
      @VisibleForTesting
      static Set<Range<Token>> subtractFromAllRanges(Collection<Map.Entry<Range<Token>, StreamFromOptions>> ranges, Range<Token> range)
      {
          Set<Range<Token>> result = new HashSet<>();
          for (Map.Entry<Range<Token>, ?> r : ranges)
              result.addAll(r.getKey().subtract(range)); // subtract can return two ranges if we remove the middle part
          return result;
      }
  
      /**
       * Returns all intersections between the ranges in ranges and the given range
       */
      private static Set<Range<Token>> intersection(Set<Map.Entry<Range<Token>, StreamFromOptions>> ranges, Range<Token> range)
      {
          Set<Range<Token>> result = new HashSet<>();
          for (Map.Entry<Range<Token>, StreamFromOptions> r : ranges)
              result.addAll(range.intersectionWith(r.getKey()));
          return result;
      }
  
      /**
       * copied from Range - need to iterate over the map entries
       */
      public static Set<Range<Token>> subtractAll(Collection<Map.Entry<Range<Token>, StreamFromOptions>> ranges, Range<Token> toSubtract)
      {
          Set<Range<Token>> result = new HashSet<>();
          result.add(toSubtract);
          for(Map.Entry<Range<Token>, StreamFromOptions> range : ranges)
          {
              result = substractAllFromToken(result, range.getKey());
          }
  
          return result;
      }
  
      private static <T extends RingPosition<T>> Set<Range<T>> substractAllFromToken(Set<Range<T>> ranges, Range<T> subtract)
      {
          Set<Range<T>> result = new HashSet<>();
          for(Range<T> range : ranges)
          {
              result.addAll(range.subtract(subtract));
          }
  
          return result;
      }
  }
  