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.rows;
  
  import java.util.Comparator;
  import javax.annotation.Nonnull;
  
  import com.google.common.base.Function;
  
  import org.apache.cassandra.cache.IMeasurableMemory;
  import org.apache.cassandra.db.DeletionPurger;
  import org.apache.cassandra.db.DeletionTime;
  import org.apache.cassandra.db.Digest;
  import org.apache.cassandra.db.partitions.PartitionUpdate;
  import org.apache.cassandra.schema.ColumnMetadata;
  import org.apache.cassandra.serializers.MarshalException;
  import org.apache.cassandra.utils.btree.BTree;
  import org.apache.cassandra.utils.btree.UpdateFunction;
  import org.apache.cassandra.utils.caching.TinyThreadLocalPool;
  import org.apache.cassandra.utils.memory.Cloner;
  
  /**
   * Generic interface for the data of a given column (inside a row).
   *
   * In practice, there is only 2 implementations of this: either {@link Cell} for simple columns
   * or {@code ComplexColumnData} for complex columns.
   */
  public abstract class ColumnData implements IMeasurableMemory
  {
      public static final Comparator<ColumnData> comparator = (cd1, cd2) -> cd1.column().compareTo(cd2.column());
  
  
      /**
       * Construct an UpdateFunction for reconciling normal ColumnData
       * (i.e. not suitable for ComplexColumnDeletion sentinels, but suitable ComplexColumnData or Cell)
       *
       * @param updateF a consumer receiving all pairs of reconciled cells
       * @param activeDeletion the row or partition deletion time to use for purging
       */
      public static Reconciler reconciler(PostReconciliationFunction updateF, DeletionTime activeDeletion)
      {
          TinyThreadLocalPool.TinyPool<Reconciler> pool = Reconciler.POOL.get();
          Reconciler reconciler = pool.poll();
          if (reconciler == null)
              reconciler = new Reconciler();
          reconciler.init(updateF, activeDeletion);
          reconciler.pool = pool;
          return reconciler;
      }
  
      public static PostReconciliationFunction noOp = new PostReconciliationFunction()
      {
          @Override
          public Cell<?> merge(Cell<?> previous, Cell<?> insert)
          {
              return insert;
          }
  
          @Override
          public ColumnData insert(ColumnData insert)
          {
              return insert;
          }
  
          @Override
          public void delete(ColumnData existing)
          {
          }
  
          public void onAllocatedOnHeap(long delta)
          {
          }
      };
  
      public interface PostReconciliationFunction
      {
  
          ColumnData insert(ColumnData insert);
  
          Cell<?> merge(Cell<?> previous, Cell<?> insert);
  
          void delete(ColumnData existing);
  
          void onAllocatedOnHeap(long delta);
      }
  
      public static class Reconciler implements UpdateFunction<ColumnData, ColumnData>, AutoCloseable
      {
          private static final TinyThreadLocalPool<Reconciler> POOL = new TinyThreadLocalPool<>();
          private PostReconciliationFunction postReconcile;
          private DeletionTime activeDeletion;
          private TinyThreadLocalPool.TinyPool<Reconciler> pool;
  
          private void init(PostReconciliationFunction postReconcile, DeletionTime activeDeletion)
          {
              this.postReconcile = postReconcile;
              this.activeDeletion = activeDeletion;
          }
  
          public ColumnData merge(ColumnData existing, ColumnData update)
          {
              if (!(existing instanceof ComplexColumnData))
              {
                  Cell<?> existingCell = (Cell<?>) existing, updateCell = (Cell<?>) update;
                  Cell<?> result = Cells.reconcile(existingCell, updateCell);
  
                  return postReconcile.merge(existingCell, result);
              }
              else
              {
                  ComplexColumnData existingComplex = (ComplexColumnData) existing;
                  ComplexColumnData updateComplex = (ComplexColumnData) update;
  
                  DeletionTime existingDeletion = existingComplex.complexDeletion();
                  DeletionTime updateDeletion = updateComplex.complexDeletion();
                  DeletionTime maxComplexDeletion = existingDeletion.supersedes(updateDeletion) ? existingDeletion : updateDeletion;
  
                  Object[] existingTree = existingComplex.tree();
                  Object[] updateTree = updateComplex.tree();
  
                  Object[] cells;
  
                  try (Reconciler reconciler = reconciler(postReconcile, maxComplexDeletion))
                  {
                      if (!maxComplexDeletion.isLive())
                      {
                          if (maxComplexDeletion == existingDeletion)
                          {
                              updateTree = BTree.<ColumnData, ColumnData>transformAndFilter(updateTree, reconciler::removeShadowed);
                          }
                          else
                          {
                              Object[] retained = BTree.transformAndFilter(existingTree, reconciler::retain);
                              if (existingTree != retained)
                              {
                                  onAllocatedOnHeap(BTree.sizeOnHeapOf(retained) - BTree.sizeOnHeapOf(existingTree));
                                  existingTree = retained;
                              }
                          }
                      }
                      cells = BTree.update(existingTree, updateTree, existingComplex.column.cellComparator(), (UpdateFunction) reconciler);
                  }
                  return new ComplexColumnData(existingComplex.column, cells, maxComplexDeletion);
              }
          }
  
          @Override
          public void onAllocatedOnHeap(long heapSize)
          {
              postReconcile.onAllocatedOnHeap(heapSize);
          }
  
          @Override
          public ColumnData insert(ColumnData insert)
          {
              return postReconcile.insert(insert);
          }
  
          /**
           * Checks if the specified value  should be deleted or not.
           *
           * @param existing the existing value to check
           * @return {@code null} if the value should be removed from the BTree or the existing value if it should not.
           */
          public ColumnData retain(ColumnData existing)
          {
              return removeShadowed(existing, postReconcile);
          }
  
          private ColumnData removeShadowed(ColumnData existing)
          {
              return removeShadowed(existing, ColumnData.noOp);
          }
  
          /**
           * Checks if the specified value  should be deleted or not.
           *
           * @param existing the existing value to check
           * @return {@code null} if the value should be removed from the BTree or the existing value if it should not.
           */
          private ColumnData removeShadowed(ColumnData existing, PostReconciliationFunction recordDeletion)
          {
              if (!(existing instanceof ComplexColumnData))
              {
                  if (activeDeletion.deletes((Cell<?>) existing))
                  {
                      recordDeletion.delete(existing);
                      return null;
                  }
              }
              else
              {
                  ComplexColumnData existingComplex = (ComplexColumnData) existing;
                  if (activeDeletion.supersedes(existingComplex.complexDeletion()))
                  {
                      Object[] cells = BTree.transformAndFilter(existingComplex.tree(), (ColumnData cd) -> removeShadowed(cd, recordDeletion));
                      return BTree.isEmpty(cells) ? null : new ComplexColumnData(existingComplex.column, cells, DeletionTime.LIVE);
                  }
              }
  
              return existing;
          }
  
          public void close()
          {
              activeDeletion = null;
              postReconcile = null;
  
              TinyThreadLocalPool.TinyPool<Reconciler> tmp = pool;
              pool = null;
              tmp.offer(this);
  
          }
      }
  
      protected final ColumnMetadata column;
      protected ColumnData(ColumnMetadata column)
      {
          this.column = column;
      }
  
      /**
       * The column this is data for.
       *
       * @return the column this is a data for.
       */
      public final ColumnMetadata column() { return column; }
  
      /**
       * The size of the data hold by this {@code ColumnData}.
       *
       * @return the size used by the data of this {@code ColumnData}.
       */
      public abstract int dataSize();
  
      public abstract long unsharedHeapSizeExcludingData();
  
      public abstract long unsharedHeapSize();
  
      /**
       * Validate the column data.
       *
       * @throws MarshalException if the data is not valid.
       */
      public abstract void validate();
  
      /**
       * Validates the deletions (ttl and local deletion time) if any.
       *
       * @return true if it has any invalid deletions, false otherwise
       */
      public abstract boolean hasInvalidDeletions();
  
      /**
       * Adds the data to the provided digest.
       *
       * @param digest the {@link Digest} to add the data to.
       */
      public abstract void digest(Digest digest);
  
      public static void digest(Digest digest, ColumnData cd)
      {
          cd.digest(digest);
      }
  
      public abstract ColumnData clone(Cloner cloner);
  
      /**
       * Returns a copy of the data where all timestamps for live data have replaced by {@code newTimestamp} and
       * all deletion timestamp by {@code newTimestamp - 1}.
       *
       * This exists for the Paxos path, see {@link PartitionUpdate#updateAllTimestamp} for additional details.
       */
      public abstract ColumnData updateAllTimestamp(long newTimestamp);
  
      /**
       * @param cellToMaybeNewListPath If the cell is a list append cell a new cell path is returned generated based on the Accord executeAt timestamp
       */
      public abstract ColumnData updateTimesAndPathsForAccord(@Nonnull Function<Cell, CellPath> cellToMaybeNewListPath, long newTimestamp, long newLocalDeletionTime);
  
      /**
       * List paths are time UUIDs that increment for each item in the list and for Accord and Paxos
       * should be based on the transaction's ballot/timestamp.
       *
       * @param maybeNewPath If this cell is a list append for a non-frozen list (multi-cell) then it will be new path generated using the executeAt timestamp, otherwise it will be the existing path
       */
      public abstract ColumnData updateAllTimesWithNewCellPathForComplexColumnData(@Nonnull CellPath maybeNewPath, long newTimestamp, long newLocalDeletionTime);
  
      public abstract ColumnData markCounterLocalToBeCleared();
  
      public abstract ColumnData purge(DeletionPurger purger, long nowInSec);
      public abstract ColumnData purgeDataOlderThan(long timestamp);
  
      public abstract long maxTimestamp();
  }
  