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;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Objects;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  import javax.annotation.concurrent.ThreadSafe;
  
  import com.google.common.annotations.VisibleForTesting;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.index.sai.disk.format.IndexDescriptor;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  import org.apache.cassandra.utils.Pair;
  
  /**
   * Manages per-sstable {@link SSTableContext}s for {@link StorageAttachedIndexGroup}
   */
  @ThreadSafe
  public class SSTableContextManager
  {
      private static final Logger logger = LoggerFactory.getLogger(SSTableContextManager.class);
  
      private final ConcurrentHashMap<SSTableReader, SSTableContext> sstableContexts = new ConcurrentHashMap<>();
  
      /**
       * Initialize {@link SSTableContext}s if they are not already initialized.
       *
       * @param removed SSTables being removed
       * @param added SSTables being added
       * @param validation Controls how indexes should be validated
       *
       * @return a set of contexts for SSTables with valid per-SSTable components, and a set of
       * SSTables with invalid or missing components
       */
      public Pair<Set<SSTableContext>, Set<SSTableReader>> update(Collection<SSTableReader> removed, Iterable<SSTableReader> added, IndexValidation validation)
      {
          release(removed);
  
          Set<SSTableContext> contexts = new HashSet<>();
          Set<SSTableReader> invalid = new HashSet<>();
  
          for (SSTableReader sstable : added)
          {
              if (sstable.isMarkedCompacted())
              {
                  continue;
              }
  
              IndexDescriptor indexDescriptor = IndexDescriptor.create(sstable);
  
              if (!indexDescriptor.isPerSSTableIndexBuildComplete())
              {
                  // Don't even try to validate or add the context if the completion marker is missing.
                  continue;
              }
  
              try
              {
                  // Only validate on restart or newly refreshed SSTable. Newly built files are unlikely to be corrupted.
                  if (!sstableContexts.containsKey(sstable) && !indexDescriptor.validatePerSSTableComponents(validation, true, false))
                  {
                      invalid.add(sstable);
                      removeInvalidSSTableContext(sstable);
                      continue;
                  }
                  // ConcurrentHashMap#computeIfAbsent guarantees atomicity, so {@link SSTableContext#create(SSTableReader)}}
                  // is called at most once per key.
                  contexts.add(sstableContexts.computeIfAbsent(sstable, SSTableContext::create));
              }
              catch (Throwable t)
              {
                  logger.warn(indexDescriptor.logMessage("Failed to update per-SSTable components for SSTable {}"), sstable.descriptor, t);
                  invalid.add(sstable);
                  removeInvalidSSTableContext(sstable);
              }
          }
  
          return Pair.create(contexts, invalid);
      }
  
      public void release(Collection<SSTableReader> toRelease)
      {
          toRelease.stream().map(sstableContexts::remove).filter(Objects::nonNull).forEach(SSTableContext::close);
      }
  
      /**
       * @return total number of per-sstable open files for live sstables
       */
      int openFiles()
      {
          return sstableContexts.values().stream().mapToInt(SSTableContext::openFilesPerSSTable).sum();
      }
  
      /**
       * @return total disk usage (in bytes) of all per-sstable index files
       */
      long diskUsage()
      {
          return sstableContexts.values().stream().mapToLong(SSTableContext::diskUsage).sum();
      }
  
      Set<SSTableReader> sstables()
      {
          return sstableContexts.keySet();
      }
  
      @VisibleForTesting
      public int size()
      {
          return sstableContexts.size();
      }
  
      @VisibleForTesting
      public void clear()
      {
          sstableContexts.values().forEach(SSTableContext::close);
          sstableContexts.clear();
      }
  
      @SuppressWarnings("EmptyTryBlock")
      private void removeInvalidSSTableContext(SSTableReader sstable)
      {
          try (SSTableContext ignored = sstableContexts.remove(sstable))
          {
          }
      }
  }
  