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.io.sstable.format.big;
  
  import java.io.IOException;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.db.DecoratedKey;
  import org.apache.cassandra.dht.IPartitioner;
  import org.apache.cassandra.io.sstable.indexsummary.IndexSummary;
  import org.apache.cassandra.io.util.DataOutputStreamPlus;
  import org.apache.cassandra.io.util.File;
  import org.apache.cassandra.io.util.FileInputStreamPlus;
  import org.apache.cassandra.schema.TableMetadata;
  import org.apache.cassandra.utils.ByteBufferUtil;
  import org.apache.cassandra.utils.Pair;
  
  public class IndexSummaryComponent
  {
      private static final Logger logger = LoggerFactory.getLogger(IndexSummaryComponent.class);
  
      public final IndexSummary indexSummary;
      public final DecoratedKey first;
      public final DecoratedKey last;
  
      public IndexSummaryComponent(IndexSummary indexSummary, DecoratedKey first, DecoratedKey last)
      {
          this.indexSummary = indexSummary;
          this.first = first;
          this.last = last;
      }
  
      public static Pair<DecoratedKey, DecoratedKey> loadFirstAndLastKey(File summaryFile, IPartitioner partitioner) throws IOException
      {
          if (!summaryFile.exists())
          {
              if (logger.isDebugEnabled())
                  logger.debug("Index summary {} does not exist", summaryFile.absolutePath());
              return null;
          }
  
          try (FileInputStreamPlus iStream = summaryFile.newInputStream())
          {
              return new IndexSummary.IndexSummarySerializer().deserializeFirstLastKey(iStream, partitioner);
          }
      }
  
      /**
       * Load index summary, first key and last key from Summary.db file if it exists.
       * <p>
       * if loaded index summary has different index interval from current value stored in schema,
       * then Summary.db file will be deleted and need to be rebuilt.
       */
      public static IndexSummaryComponent load(File summaryFile, TableMetadata metadata) throws IOException
      {
          if (!summaryFile.exists())
          {
              if (logger.isDebugEnabled())
                  logger.debug("Index summary {} does not exist", summaryFile.absolutePath());
              return null;
          }
  
          IndexSummary summary = null;
          try (FileInputStreamPlus iStream = summaryFile.newInputStream())
          {
              summary = IndexSummary.serializer.deserialize(iStream,
                                                            metadata.partitioner,
                                                            metadata.params.minIndexInterval,
                                                            metadata.params.maxIndexInterval);
              DecoratedKey first = metadata.partitioner.decorateKey(ByteBufferUtil.readWithLength(iStream));
              DecoratedKey last = metadata.partitioner.decorateKey(ByteBufferUtil.readWithLength(iStream));
  
              return new IndexSummaryComponent(summary, first, last);
          }
          catch (IOException ex)
          {
              if (summary != null)
                  summary.close();
  
              throw new IOException(String.format("Cannot deserialize index summary from %s", summaryFile), ex);
          }
      }
  
      public static IndexSummaryComponent loadOrDeleteCorrupted(File summaryFile, TableMetadata metadata) throws IOException
      {
          try
          {
              return load(summaryFile, metadata);
          }
          catch (IOException ex)
          {
              summaryFile.deleteIfExists();
              throw ex;
          }
      }
  
      /**
       * Save index summary to Summary.db file.
       */
      public void save(File summaryFile, boolean deleteOnFailure) throws IOException
      {
          if (summaryFile.exists())
              summaryFile.delete();
  
          try (DataOutputStreamPlus oStream = summaryFile.newOutputStream(File.WriteMode.OVERWRITE))
          {
              IndexSummary.serializer.serialize(indexSummary, oStream);
              ByteBufferUtil.writeWithLength(first.getKey(), oStream);
              ByteBufferUtil.writeWithLength(last.getKey(), oStream);
          }
          catch (IOException ex)
          {
              if (deleteOnFailure)
                  summaryFile.deleteIfExists();
              throw new IOException("Failed to save index summary to " + summaryFile, ex);
          }
      }
  }
  