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.partitions;
  
  import java.util.Arrays;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import org.apache.cassandra.db.DeletionInfo;
  import org.apache.cassandra.db.RegularAndStaticColumns;
  import org.apache.cassandra.db.rows.EncodingStats;
  import org.apache.cassandra.db.rows.Row;
  import org.apache.cassandra.db.rows.Rows;
  import org.apache.cassandra.utils.ObjectSizes;
  import org.apache.cassandra.utils.btree.BTree;
  
  /**
   * Holder of the content of a partition, see {@link AbstractBTreePartition}.
   * When updating a partition one holder is swapped for another atomically.
   */
  public final class BTreePartitionData
  {
      public static final BTreePartitionData EMPTY = new BTreePartitionData(RegularAndStaticColumns.NONE,
                                                                            BTree.empty(),
                                                                            DeletionInfo.LIVE,
                                                                            Rows.EMPTY_STATIC_ROW,
                                                                            EncodingStats.NO_STATS);
      public static final long UNSHARED_HEAP_SIZE = ObjectSizes.measure(EMPTY);
  
  
      final RegularAndStaticColumns columns;
      final DeletionInfo deletionInfo;
      // the btree of rows
      final Object[] tree;
      final Row staticRow;
      public final EncodingStats stats;
  
      BTreePartitionData(RegularAndStaticColumns columns,
                         Object[] tree,
                         DeletionInfo deletionInfo,
                         Row staticRow,
                         EncodingStats stats)
      {
          this.columns = columns;
          this.tree = tree;
          this.deletionInfo = deletionInfo;
          this.staticRow = staticRow == null ? Rows.EMPTY_STATIC_ROW : staticRow;
          this.stats = stats;
      }
  
      BTreePartitionData withColumns(RegularAndStaticColumns columns)
      {
          return new BTreePartitionData(columns, this.tree, this.deletionInfo, this.staticRow, this.stats);
      }
  
      @VisibleForTesting
      public static BTreePartitionData unsafeGetEmpty()
      {
          return EMPTY;
      }
  
      @VisibleForTesting
      public static BTreePartitionData unsafeConstruct(RegularAndStaticColumns columns,
                                                       Object[] tree,
                                                       DeletionInfo deletionInfo,
                                                       Row staticRow,
                                                       EncodingStats stats)
      {
          return new BTreePartitionData(columns, tree, deletionInfo, staticRow, stats);
      }
  
      @VisibleForTesting
      public static void unsafeInvalidate(AtomicBTreePartition partition)
      {
          BTreePartitionData holder = partition.unsafeGetHolder();
          if (!BTree.isEmpty(holder.tree))
          {
              partition.unsafeSetHolder(unsafeConstruct(holder.columns,
                                                        Arrays.copyOf(holder.tree, holder.tree.length),
                                                        holder.deletionInfo,
                                                        holder.staticRow,
                                                        holder.stats));
          }
      }
  }
  