src/java/org/apache/cassandra/db/rows/BufferCell.java - cassandra - Git at Google

 /*
  * 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.io.IOException;
 import java.nio.ByteBuffer;

 import org.apache.cassandra.config.*;
 import org.apache.cassandra.db.*;
 import org.apache.cassandra.db.context.CounterContext;
 import org.apache.cassandra.db.marshal.ByteType;
 import org.apache.cassandra.io.util.DataInputPlus;
 import org.apache.cassandra.io.util.DataOutputPlus;
 import org.apache.cassandra.utils.ByteBufferUtil;
 import org.apache.cassandra.utils.ObjectSizes;
 import org.apache.cassandra.utils.FBUtilities;
 import org.apache.cassandra.utils.memory.AbstractAllocator;

 public class BufferCell extends AbstractCell
 {
     private static final long EMPTY_SIZE = ObjectSizes.measure(new BufferCell(ColumnDefinition.regularDef("", "", "", ByteType.instance), 0L, 0, 0, ByteBufferUtil.EMPTY_BYTE_BUFFER, null));

     private final long timestamp;
     private final int ttl;
     private final int localDeletionTime;

     private final ByteBuffer value;
     private final CellPath path;

     public BufferCell(ColumnDefinition column, long timestamp, int ttl, int localDeletionTime, ByteBuffer value, CellPath path)
     {
         super(column);
         assert column.isComplex() == (path != null);
         this.timestamp = timestamp;
         this.ttl = ttl;
         this.localDeletionTime = localDeletionTime;
         this.value = value;
         this.path = path;
     }

     public static BufferCell live(CFMetaData metadata, ColumnDefinition column, long timestamp, ByteBuffer value)
     {
         return live(metadata, column, timestamp, value, null);
     }

     public static BufferCell live(CFMetaData metadata, ColumnDefinition column, long timestamp, ByteBuffer value, CellPath path)
     {
         if (metadata.params.defaultTimeToLive != NO_TTL)
             return expiring(column, timestamp, metadata.params.defaultTimeToLive, FBUtilities.nowInSeconds(), value, path);

         return new BufferCell(column, timestamp, NO_TTL, NO_DELETION_TIME, value, path);
     }

     public static BufferCell expiring(ColumnDefinition column, long timestamp, int ttl, int nowInSec, ByteBuffer value)
     {
         return expiring(column, timestamp, ttl, nowInSec, value, null);
     }

     public static BufferCell expiring(ColumnDefinition column, long timestamp, int ttl, int nowInSec, ByteBuffer value, CellPath path)
     {
         assert ttl != NO_TTL;
         return new BufferCell(column, timestamp, ttl, ExpirationDateOverflowHandling.computeLocalExpirationTime(nowInSec, ttl), value, path);
     }

     public static BufferCell tombstone(ColumnDefinition column, long timestamp, int nowInSec)
     {
         return tombstone(column, timestamp, nowInSec, null);
     }

     public static BufferCell tombstone(ColumnDefinition column, long timestamp, int nowInSec, CellPath path)
     {
         return new BufferCell(column, timestamp, NO_TTL, nowInSec, ByteBufferUtil.EMPTY_BYTE_BUFFER, path);
     }

     public boolean isCounterCell()
     {
         return !isTombstone() && column.isCounterColumn();
     }

     public boolean isLive(int nowInSec)
     {
         return localDeletionTime == NO_DELETION_TIME || (ttl != NO_TTL && nowInSec < localDeletionTime);
     }

     public boolean isTombstone()
     {
         return localDeletionTime != NO_DELETION_TIME && ttl == NO_TTL;
     }

     public boolean isExpiring()
     {
         return ttl != NO_TTL;
     }

     public long timestamp()
     {
         return timestamp;
     }

     public int ttl()
     {
         return ttl;
     }

     public int localDeletionTime()
     {
         return localDeletionTime;
     }

     public ByteBuffer value()
     {
         return value;
     }

     public CellPath path()
     {
         return path;
     }

     public Cell withUpdatedColumn(ColumnDefinition newColumn)
     {
         return new BufferCell(newColumn, timestamp, ttl, localDeletionTime, value, path);
     }

     public Cell withUpdatedValue(ByteBuffer newValue)
     {
         return new BufferCell(column, timestamp, ttl, localDeletionTime, newValue, path);
     }

     public Cell withUpdatedTimestampAndLocalDeletionTime(long newTimestamp, int newLocalDeletionTime)
     {
         return new BufferCell(column, newTimestamp, ttl, newLocalDeletionTime, value, path);
     }

     public Cell copy(AbstractAllocator allocator)
     {
         if (!value.hasRemaining())
             return this;

         return new BufferCell(column, timestamp, ttl, localDeletionTime, allocator.clone(value), path == null ? null : path.copy(allocator));
     }

     public Cell markCounterLocalToBeCleared()
     {
         if (!isCounterCell())
             return this;

         ByteBuffer marked = CounterContext.instance().markLocalToBeCleared(value());
         return marked == value() ? this : new BufferCell(column, timestamp, ttl, localDeletionTime, marked, path);
     }

     public Cell purge(DeletionPurger purger, int nowInSec)
     {
         if (!isLive(nowInSec))
         {
             if (purger.shouldPurge(timestamp, localDeletionTime))
                 return null;

             // We slightly hijack purging to convert expired but not purgeable columns to tombstones. The reason we do that is
             // that once a column has expired it is equivalent to a tombstone but actually using a tombstone is more compact since
             // we don't keep the column value. The reason we do it here is that 1) it's somewhat related to dealing with tombstones
             // so hopefully not too surprising and 2) we want to this and purging at the same places, so it's simpler/more efficient
             // to do both here.
             if (isExpiring())
             {
                 // Note that as long as the expiring column and the tombstone put together live longer than GC grace seconds,
                 // we'll fulfil our responsibility to repair. See discussion at
                 // http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/repair-compaction-and-tombstone-rows-td7583481.html
                 return BufferCell.tombstone(column, timestamp, localDeletionTime - ttl, path).purge(purger, nowInSec);
             }
         }
         return this;
     }

     public Cell updateAllTimestamp(long newTimestamp)
     {
         return new BufferCell(column, isTombstone() ? newTimestamp - 1 : newTimestamp, ttl, localDeletionTime, value, path);
     }

     public int dataSize()
     {
         return TypeSizes.sizeof(timestamp)
              + TypeSizes.sizeof(ttl)
              + TypeSizes.sizeof(localDeletionTime)
              + value.remaining()
              + (path == null ? 0 : path.dataSize());
     }

     public long unsharedHeapSizeExcludingData()
     {
         return EMPTY_SIZE + ObjectSizes.sizeOnHeapExcludingData(value) + (path == null ? 0 : path.unsharedHeapSizeExcludingData());
     }

     /**
      * The serialization format for cell is:
      *     [ flags ][ timestamp ][ deletion time ][    ttl    ][ path size ][ path ][ value size ][ value ]
      *     [   1b  ][ 8b (vint) ][   4b (vint)   ][ 4b (vint) ][ 4b (vint) ][  arb ][  4b (vint) ][  arb  ]
      *
      * where not all field are always present (in fact, only the [ flags ] are guaranteed to be present). The fields have the following
      * meaning:
      *   - [ flags ] is the cell flags. It is a byte for which each bit represents a flag whose meaning is explained below (*_MASK constants)
      *   - [ timestamp ] is the cell timestamp. Present unless the cell has the USE_TIMESTAMP_MASK.
      *   - [ deletion time]: the local deletion time for the cell. Present if either the cell is deleted (IS_DELETED_MASK)
      *       or it is expiring (IS_EXPIRING_MASK) but doesn't have the USE_ROW_TTL_MASK.
      *   - [ ttl ]: the ttl for the cell. Present if the row is expiring (IS_EXPIRING_MASK) but doesn't have the
      *       USE_ROW_TTL_MASK.
      *   - [ value size ] is the size of the [ value ] field. It's present unless either the cell has the HAS_EMPTY_VALUE_MASK, or the value
      *       for columns of this type have a fixed length.
      *   - [ path size ] is the size of the [ path ] field. Present iff this is the cell of a complex column.
      *   - [ value ]: the cell value, unless it has the HAS_EMPTY_VALUE_MASK.
      *   - [ path ]: the cell path if the column this is a cell of is complex.
      */
     static class Serializer implements Cell.Serializer
     {
         private final static int IS_DELETED_MASK             = 0x01; // Whether the cell is a tombstone or not.
         private final static int IS_EXPIRING_MASK            = 0x02; // Whether the cell is expiring.
         private final static int HAS_EMPTY_VALUE_MASK        = 0x04; // Wether the cell has an empty value. This will be the case for tombstone in particular.
         private final static int USE_ROW_TIMESTAMP_MASK      = 0x08; // Wether the cell has the same timestamp than the row this is a cell of.
         private final static int USE_ROW_TTL_MASK            = 0x10; // Wether the cell has the same ttl than the row this is a cell of.

         public void serialize(Cell cell, ColumnDefinition column, DataOutputPlus out, LivenessInfo rowLiveness, SerializationHeader header) throws IOException
         {
             assert cell != null;
             boolean hasValue = cell.value().hasRemaining();
             boolean isDeleted = cell.isTombstone();
             boolean isExpiring = cell.isExpiring();
             boolean useRowTimestamp = !rowLiveness.isEmpty() && cell.timestamp() == rowLiveness.timestamp();
             boolean useRowTTL = isExpiring && rowLiveness.isExpiring() && cell.ttl() == rowLiveness.ttl() && cell.localDeletionTime() == rowLiveness.localExpirationTime();
             int flags = 0;
             if (!hasValue)
                 flags |= HAS_EMPTY_VALUE_MASK;

             if (isDeleted)
                 flags |= IS_DELETED_MASK;
             else if (isExpiring)
                 flags |= IS_EXPIRING_MASK;

             if (useRowTimestamp)
                 flags |= USE_ROW_TIMESTAMP_MASK;
             if (useRowTTL)
                 flags |= USE_ROW_TTL_MASK;

             out.writeByte((byte)flags);

             if (!useRowTimestamp)
                 header.writeTimestamp(cell.timestamp(), out);

             if ((isDeleted || isExpiring) && !useRowTTL)
                 header.writeLocalDeletionTime(cell.localDeletionTime(), out);
             if (isExpiring && !useRowTTL)
                 header.writeTTL(cell.ttl(), out);

             if (column.isComplex())
                 column.cellPathSerializer().serialize(cell.path(), out);

             if (hasValue)
                 header.getType(column).writeValue(cell.value(), out);
         }

         public Cell deserialize(DataInputPlus in, LivenessInfo rowLiveness, ColumnDefinition column, SerializationHeader header, SerializationHelper helper) throws IOException
         {
             int flags = in.readUnsignedByte();
             boolean hasValue = (flags & HAS_EMPTY_VALUE_MASK) == 0;
             boolean isDeleted = (flags & IS_DELETED_MASK) != 0;
             boolean isExpiring = (flags & IS_EXPIRING_MASK) != 0;
             boolean useRowTimestamp = (flags & USE_ROW_TIMESTAMP_MASK) != 0;
             boolean useRowTTL = (flags & USE_ROW_TTL_MASK) != 0;

             long timestamp = useRowTimestamp ? rowLiveness.timestamp() : header.readTimestamp(in);

             int localDeletionTime = useRowTTL
                                   ? rowLiveness.localExpirationTime()
                                   : (isDeleted || isExpiring ? header.readLocalDeletionTime(in) : NO_DELETION_TIME);

             int ttl = useRowTTL ? rowLiveness.ttl() : (isExpiring ? header.readTTL(in) : NO_TTL);

             CellPath path = column.isComplex()
                           ? column.cellPathSerializer().deserialize(in)
                           : null;

             boolean isCounter = localDeletionTime == NO_DELETION_TIME && column.type.isCounter();

             ByteBuffer value = ByteBufferUtil.EMPTY_BYTE_BUFFER;
             if (hasValue)
             {
                 if (helper.canSkipValue(column) || (path != null && helper.canSkipValue(path)))
                 {
                     header.getType(column).skipValue(in);
                 }
                 else
                 {
                     value = header.getType(column).readValue(in, DatabaseDescriptor.getMaxValueSize());
                     if (isCounter)
                         value = helper.maybeClearCounterValue(value);
                 }
             }

             return new BufferCell(column, timestamp, ttl, localDeletionTime, value, path);
         }

         public long serializedSize(Cell cell, ColumnDefinition column, LivenessInfo rowLiveness, SerializationHeader header)
         {
             long size = 1; // flags
             boolean hasValue = cell.value().hasRemaining();
             boolean isDeleted = cell.isTombstone();
             boolean isExpiring = cell.isExpiring();
             boolean useRowTimestamp = !rowLiveness.isEmpty() && cell.timestamp() == rowLiveness.timestamp();
             boolean useRowTTL = isExpiring && rowLiveness.isExpiring() && cell.ttl() == rowLiveness.ttl() && cell.localDeletionTime() == rowLiveness.localExpirationTime();

             if (!useRowTimestamp)
                 size += header.timestampSerializedSize(cell.timestamp());

             if ((isDeleted || isExpiring) && !useRowTTL)
                 size += header.localDeletionTimeSerializedSize(cell.localDeletionTime());
             if (isExpiring && !useRowTTL)
                 size += header.ttlSerializedSize(cell.ttl());

             if (column.isComplex())
                 size += column.cellPathSerializer().serializedSize(cell.path());

             if (hasValue)
                 size += header.getType(column).writtenLength(cell.value());

             return size;
         }

         // Returns if the skipped cell was an actual cell (i.e. it had its presence flag).
         public boolean skip(DataInputPlus in, ColumnDefinition column, SerializationHeader header) throws IOException
         {
             int flags = in.readUnsignedByte();
             boolean hasValue = (flags & HAS_EMPTY_VALUE_MASK) == 0;
             boolean isDeleted = (flags & IS_DELETED_MASK) != 0;
             boolean isExpiring = (flags & IS_EXPIRING_MASK) != 0;
             boolean useRowTimestamp = (flags & USE_ROW_TIMESTAMP_MASK) != 0;
             boolean useRowTTL = (flags & USE_ROW_TTL_MASK) != 0;

             if (!useRowTimestamp)
                 header.skipTimestamp(in);

             if (!useRowTTL && (isDeleted || isExpiring))
                 header.skipLocalDeletionTime(in);

             if (!useRowTTL && isExpiring)
                 header.skipTTL(in);

             if (column.isComplex())
                 column.cellPathSerializer().skip(in);

             if (hasValue)
                 header.getType(column).skipValue(in);

             return true;
         }
     }
 }
	/*
	* 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.io.IOException;
	import java.nio.ByteBuffer;

	import org.apache.cassandra.config.*;
	import org.apache.cassandra.db.*;
	import org.apache.cassandra.db.context.CounterContext;
	import org.apache.cassandra.db.marshal.ByteType;
	import org.apache.cassandra.io.util.DataInputPlus;
	import org.apache.cassandra.io.util.DataOutputPlus;
	import org.apache.cassandra.utils.ByteBufferUtil;
	import org.apache.cassandra.utils.ObjectSizes;
	import org.apache.cassandra.utils.FBUtilities;
	import org.apache.cassandra.utils.memory.AbstractAllocator;

	public class BufferCell extends AbstractCell
	{
	private static final long EMPTY_SIZE = ObjectSizes.measure(new BufferCell(ColumnDefinition.regularDef("", "", "", ByteType.instance), 0L, 0, 0, ByteBufferUtil.EMPTY_BYTE_BUFFER, null));

	private final long timestamp;
	private final int ttl;
	private final int localDeletionTime;

	private final ByteBuffer value;
	private final CellPath path;

	public BufferCell(ColumnDefinition column, long timestamp, int ttl, int localDeletionTime, ByteBuffer value, CellPath path)
	{
	super(column);
	assert column.isComplex() == (path != null);
	this.timestamp = timestamp;
	this.ttl = ttl;
	this.localDeletionTime = localDeletionTime;
	this.value = value;
	this.path = path;
	}

	public static BufferCell live(CFMetaData metadata, ColumnDefinition column, long timestamp, ByteBuffer value)
	{
	return live(metadata, column, timestamp, value, null);
	}

	public static BufferCell live(CFMetaData metadata, ColumnDefinition column, long timestamp, ByteBuffer value, CellPath path)
	{
	if (metadata.params.defaultTimeToLive != NO_TTL)
	return expiring(column, timestamp, metadata.params.defaultTimeToLive, FBUtilities.nowInSeconds(), value, path);

	return new BufferCell(column, timestamp, NO_TTL, NO_DELETION_TIME, value, path);
	}

	public static BufferCell expiring(ColumnDefinition column, long timestamp, int ttl, int nowInSec, ByteBuffer value)
	{
	return expiring(column, timestamp, ttl, nowInSec, value, null);
	}

	public static BufferCell expiring(ColumnDefinition column, long timestamp, int ttl, int nowInSec, ByteBuffer value, CellPath path)
	{
	assert ttl != NO_TTL;
	return new BufferCell(column, timestamp, ttl, ExpirationDateOverflowHandling.computeLocalExpirationTime(nowInSec, ttl), value, path);
	}

	public static BufferCell tombstone(ColumnDefinition column, long timestamp, int nowInSec)
	{
	return tombstone(column, timestamp, nowInSec, null);
	}

	public static BufferCell tombstone(ColumnDefinition column, long timestamp, int nowInSec, CellPath path)
	{
	return new BufferCell(column, timestamp, NO_TTL, nowInSec, ByteBufferUtil.EMPTY_BYTE_BUFFER, path);
	}

	public boolean isCounterCell()
	{
	return !isTombstone() && column.isCounterColumn();
	}

	public boolean isLive(int nowInSec)
	{
	return localDeletionTime == NO_DELETION_TIME \|\| (ttl != NO_TTL && nowInSec < localDeletionTime);
	}

	public boolean isTombstone()
	{
	return localDeletionTime != NO_DELETION_TIME && ttl == NO_TTL;
	}

	public boolean isExpiring()
	{
	return ttl != NO_TTL;
	}

	public long timestamp()
	{
	return timestamp;
	}

	public int ttl()
	{
	return ttl;
	}

	public int localDeletionTime()
	{
	return localDeletionTime;
	}

	public ByteBuffer value()
	{
	return value;
	}

	public CellPath path()
	{
	return path;
	}

	public Cell withUpdatedColumn(ColumnDefinition newColumn)
	{
	return new BufferCell(newColumn, timestamp, ttl, localDeletionTime, value, path);
	}

	public Cell withUpdatedValue(ByteBuffer newValue)
	{
	return new BufferCell(column, timestamp, ttl, localDeletionTime, newValue, path);
	}

	public Cell withUpdatedTimestampAndLocalDeletionTime(long newTimestamp, int newLocalDeletionTime)
	{
	return new BufferCell(column, newTimestamp, ttl, newLocalDeletionTime, value, path);
	}

	public Cell copy(AbstractAllocator allocator)
	{
	if (!value.hasRemaining())
	return this;

	return new BufferCell(column, timestamp, ttl, localDeletionTime, allocator.clone(value), path == null ? null : path.copy(allocator));
	}

	public Cell markCounterLocalToBeCleared()
	{
	if (!isCounterCell())
	return this;

	ByteBuffer marked = CounterContext.instance().markLocalToBeCleared(value());
	return marked == value() ? this : new BufferCell(column, timestamp, ttl, localDeletionTime, marked, path);
	}

	public Cell purge(DeletionPurger purger, int nowInSec)
	{
	if (!isLive(nowInSec))
	{
	if (purger.shouldPurge(timestamp, localDeletionTime))
	return null;

	// We slightly hijack purging to convert expired but not purgeable columns to tombstones. The reason we do that is
	// that once a column has expired it is equivalent to a tombstone but actually using a tombstone is more compact since
	// we don't keep the column value. The reason we do it here is that 1) it's somewhat related to dealing with tombstones
	// so hopefully not too surprising and 2) we want to this and purging at the same places, so it's simpler/more efficient
	// to do both here.
	if (isExpiring())
	{
	// Note that as long as the expiring column and the tombstone put together live longer than GC grace seconds,
	// we'll fulfil our responsibility to repair. See discussion at
	// http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/repair-compaction-and-tombstone-rows-td7583481.html
	return BufferCell.tombstone(column, timestamp, localDeletionTime - ttl, path).purge(purger, nowInSec);
	}
	}
	return this;
	}

	public Cell updateAllTimestamp(long newTimestamp)
	{
	return new BufferCell(column, isTombstone() ? newTimestamp - 1 : newTimestamp, ttl, localDeletionTime, value, path);
	}

	public int dataSize()
	{
	return TypeSizes.sizeof(timestamp)
	+ TypeSizes.sizeof(ttl)
	+ TypeSizes.sizeof(localDeletionTime)
	+ value.remaining()
	+ (path == null ? 0 : path.dataSize());
	}

	public long unsharedHeapSizeExcludingData()
	{
	return EMPTY_SIZE + ObjectSizes.sizeOnHeapExcludingData(value) + (path == null ? 0 : path.unsharedHeapSizeExcludingData());
	}

	/**
	* The serialization format for cell is:
	* [ flags ][ timestamp ][ deletion time ][ ttl ][ path size ][ path ][ value size ][ value ]
	* [ 1b ][ 8b (vint) ][ 4b (vint) ][ 4b (vint) ][ 4b (vint) ][ arb ][ 4b (vint) ][ arb ]
	*
	* where not all field are always present (in fact, only the [ flags ] are guaranteed to be present). The fields have the following
	* meaning:
	* - [ flags ] is the cell flags. It is a byte for which each bit represents a flag whose meaning is explained below (*_MASK constants)
	* - [ timestamp ] is the cell timestamp. Present unless the cell has the USE_TIMESTAMP_MASK.
	* - [ deletion time]: the local deletion time for the cell. Present if either the cell is deleted (IS_DELETED_MASK)
	* or it is expiring (IS_EXPIRING_MASK) but doesn't have the USE_ROW_TTL_MASK.
	* - [ ttl ]: the ttl for the cell. Present if the row is expiring (IS_EXPIRING_MASK) but doesn't have the
	* USE_ROW_TTL_MASK.
	* - [ value size ] is the size of the [ value ] field. It's present unless either the cell has the HAS_EMPTY_VALUE_MASK, or the value
	* for columns of this type have a fixed length.
	* - [ path size ] is the size of the [ path ] field. Present iff this is the cell of a complex column.
	* - [ value ]: the cell value, unless it has the HAS_EMPTY_VALUE_MASK.
	* - [ path ]: the cell path if the column this is a cell of is complex.
	*/
	static class Serializer implements Cell.Serializer
	{
	private final static int IS_DELETED_MASK = 0x01; // Whether the cell is a tombstone or not.
	private final static int IS_EXPIRING_MASK = 0x02; // Whether the cell is expiring.
	private final static int HAS_EMPTY_VALUE_MASK = 0x04; // Wether the cell has an empty value. This will be the case for tombstone in particular.
	private final static int USE_ROW_TIMESTAMP_MASK = 0x08; // Wether the cell has the same timestamp than the row this is a cell of.
	private final static int USE_ROW_TTL_MASK = 0x10; // Wether the cell has the same ttl than the row this is a cell of.

	public void serialize(Cell cell, ColumnDefinition column, DataOutputPlus out, LivenessInfo rowLiveness, SerializationHeader header) throws IOException
	{
	assert cell != null;
	boolean hasValue = cell.value().hasRemaining();
	boolean isDeleted = cell.isTombstone();
	boolean isExpiring = cell.isExpiring();
	boolean useRowTimestamp = !rowLiveness.isEmpty() && cell.timestamp() == rowLiveness.timestamp();
	boolean useRowTTL = isExpiring && rowLiveness.isExpiring() && cell.ttl() == rowLiveness.ttl() && cell.localDeletionTime() == rowLiveness.localExpirationTime();
	int flags = 0;
	if (!hasValue)
	flags \|= HAS_EMPTY_VALUE_MASK;

	if (isDeleted)
	flags \|= IS_DELETED_MASK;
	else if (isExpiring)
	flags \|= IS_EXPIRING_MASK;

	if (useRowTimestamp)
	flags \|= USE_ROW_TIMESTAMP_MASK;
	if (useRowTTL)
	flags \|= USE_ROW_TTL_MASK;

	out.writeByte((byte)flags);

	if (!useRowTimestamp)
	header.writeTimestamp(cell.timestamp(), out);

	if ((isDeleted \|\| isExpiring) && !useRowTTL)
	header.writeLocalDeletionTime(cell.localDeletionTime(), out);
	if (isExpiring && !useRowTTL)
	header.writeTTL(cell.ttl(), out);

	if (column.isComplex())
	column.cellPathSerializer().serialize(cell.path(), out);

	if (hasValue)
	header.getType(column).writeValue(cell.value(), out);
	}

	public Cell deserialize(DataInputPlus in, LivenessInfo rowLiveness, ColumnDefinition column, SerializationHeader header, SerializationHelper helper) throws IOException
	{
	int flags = in.readUnsignedByte();
	boolean hasValue = (flags & HAS_EMPTY_VALUE_MASK) == 0;
	boolean isDeleted = (flags & IS_DELETED_MASK) != 0;
	boolean isExpiring = (flags & IS_EXPIRING_MASK) != 0;
	boolean useRowTimestamp = (flags & USE_ROW_TIMESTAMP_MASK) != 0;
	boolean useRowTTL = (flags & USE_ROW_TTL_MASK) != 0;

	long timestamp = useRowTimestamp ? rowLiveness.timestamp() : header.readTimestamp(in);

	int localDeletionTime = useRowTTL
	? rowLiveness.localExpirationTime()
	: (isDeleted \|\| isExpiring ? header.readLocalDeletionTime(in) : NO_DELETION_TIME);

	int ttl = useRowTTL ? rowLiveness.ttl() : (isExpiring ? header.readTTL(in) : NO_TTL);

	CellPath path = column.isComplex()
	? column.cellPathSerializer().deserialize(in)
	: null;

	boolean isCounter = localDeletionTime == NO_DELETION_TIME && column.type.isCounter();

	ByteBuffer value = ByteBufferUtil.EMPTY_BYTE_BUFFER;
	if (hasValue)
	{
	if (helper.canSkipValue(column) \|\| (path != null && helper.canSkipValue(path)))
	{
	header.getType(column).skipValue(in);
	}
	else
	{
	value = header.getType(column).readValue(in, DatabaseDescriptor.getMaxValueSize());
	if (isCounter)
	value = helper.maybeClearCounterValue(value);
	}
	}

	return new BufferCell(column, timestamp, ttl, localDeletionTime, value, path);
	}

	public long serializedSize(Cell cell, ColumnDefinition column, LivenessInfo rowLiveness, SerializationHeader header)
	{
	long size = 1; // flags
	boolean hasValue = cell.value().hasRemaining();
	boolean isDeleted = cell.isTombstone();
	boolean isExpiring = cell.isExpiring();
	boolean useRowTimestamp = !rowLiveness.isEmpty() && cell.timestamp() == rowLiveness.timestamp();
	boolean useRowTTL = isExpiring && rowLiveness.isExpiring() && cell.ttl() == rowLiveness.ttl() && cell.localDeletionTime() == rowLiveness.localExpirationTime();

	if (!useRowTimestamp)
	size += header.timestampSerializedSize(cell.timestamp());

	if ((isDeleted \|\| isExpiring) && !useRowTTL)
	size += header.localDeletionTimeSerializedSize(cell.localDeletionTime());
	if (isExpiring && !useRowTTL)
	size += header.ttlSerializedSize(cell.ttl());

	if (column.isComplex())
	size += column.cellPathSerializer().serializedSize(cell.path());

	if (hasValue)
	size += header.getType(column).writtenLength(cell.value());

	return size;
	}

	// Returns if the skipped cell was an actual cell (i.e. it had its presence flag).
	public boolean skip(DataInputPlus in, ColumnDefinition column, SerializationHeader header) throws IOException
	{
	int flags = in.readUnsignedByte();
	boolean hasValue = (flags & HAS_EMPTY_VALUE_MASK) == 0;
	boolean isDeleted = (flags & IS_DELETED_MASK) != 0;
	boolean isExpiring = (flags & IS_EXPIRING_MASK) != 0;
	boolean useRowTimestamp = (flags & USE_ROW_TIMESTAMP_MASK) != 0;
	boolean useRowTTL = (flags & USE_ROW_TTL_MASK) != 0;

	if (!useRowTimestamp)
	header.skipTimestamp(in);

	if (!useRowTTL && (isDeleted \|\| isExpiring))
	header.skipLocalDeletionTime(in);

	if (!useRowTTL && isExpiring)
	header.skipTTL(in);

	if (column.isComplex())
	column.cellPathSerializer().skip(in);

	if (hasValue)
	header.getType(column).skipValue(in);

	return true;
	}
	}
	}