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.db.compaction;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.IdentityHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  import org.apache.cassandra.io.util.File;
  
  public class ActiveCompactions implements ActiveCompactionsTracker
  {
      // a synchronized identity set of running tasks to their compaction info
      private final Set<CompactionInfo.Holder> compactions = Collections.synchronizedSet(Collections.newSetFromMap(new IdentityHashMap<>()));
  
      public List<CompactionInfo.Holder> getCompactions()
      {
          return new ArrayList<>(compactions);
      }
  
      public void beginCompaction(CompactionInfo.Holder ci)
      {
          compactions.add(ci);
      }
  
      public void finishCompaction(CompactionInfo.Holder ci)
      {
          compactions.remove(ci);
          CompactionManager.instance.getMetrics().bytesCompacted.inc(ci.getCompactionInfo().getTotal());
          CompactionManager.instance.getMetrics().totalCompactionsCompleted.mark();
      }
  
      /**
       * Get the estimated number of bytes remaining to write per sstable directory
       */
      public Map<File, Long> estimatedRemainingWriteBytes()
      {
          synchronized (compactions)
          {
              Map<File, Long> writeBytesPerSSTableDir = new HashMap<>();
              for (CompactionInfo.Holder holder : compactions)
              {
                  CompactionInfo compactionInfo = holder.getCompactionInfo();
                  List<File> directories = compactionInfo.getTargetDirectories();
                  if (directories == null || directories.isEmpty())
                      continue;
                  long remainingWriteBytesPerDataDir = compactionInfo.estimatedRemainingWriteBytes() / directories.size();
                  for (File directory : directories)
                      writeBytesPerSSTableDir.merge(directory, remainingWriteBytesPerDataDir, Long::sum);
              }
              return writeBytesPerSSTableDir;
          }
      }
  
      /**
       * Iterates over the active compactions and tries to find CompactionInfos with the given compactionType for the given sstable
       *
       * Number of entries in compactions should be small (< 10) but avoid calling in any time-sensitive context
       */
      public Collection<CompactionInfo> getCompactionsForSSTable(SSTableReader sstable, OperationType compactionType)
      {
          List<CompactionInfo> toReturn = null;
          synchronized (compactions)
          {
              for (CompactionInfo.Holder holder : compactions)
              {
                  CompactionInfo compactionInfo = holder.getCompactionInfo();
                  if (compactionInfo.getSSTables().contains(sstable) && compactionInfo.getTaskType() == compactionType)
                  {
                      if (toReturn == null)
                          toReturn = new ArrayList<>();
                      toReturn.add(compactionInfo);
                  }
              }
          }
          return toReturn;
      }
  }
  