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NodeLabelsField.java
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NodeLabelsField.java
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/*
* Copyright (c) 2002-2017 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.kernel.impl.store;
import org.neo4j.kernel.impl.store.record.DynamicRecord;
import org.neo4j.kernel.impl.store.record.NodeRecord;
/**
* Logic for parsing and constructing {@link NodeRecord#getLabelField()} and dynamic label
* records in {@link NodeRecord#getDynamicLabelRecords()} from label ids.
* <p>
* Each node has a label field of 5 bytes, where labels will be stored, if sufficient space
* (max bits required for storing each label id is considered). If not then the field will
* point to a dynamic record where the labels will be stored in the format of an array property.
* <p>
* [hhhh,bbbb][bbbb,bbbb][bbbb,bbbb][bbbb,bbbb][bbbb,bbbb]
* h: header
* - 0x0<=h<=0x7 (leaving high bit reserved): number of in-lined labels in the body
* - 0x8: body will be a pointer to first dynamic record in node-labels dynamic store
* b: body
* - 0x0<=h<=0x7 (leaving high bit reserved): bits of this many in-lined label ids
* - 0x8: pointer to node-labels store
*/
public class NodeLabelsField
{
private NodeLabelsField()
{
}
public static NodeLabels parseLabelsField( NodeRecord node )
{
long labelField = node.getLabelField();
return fieldPointsToDynamicRecordOfLabels( labelField )
? new DynamicNodeLabels( node )
: new InlineNodeLabels( node );
}
public static long[] get( NodeRecord node, NodeStore nodeStore )
{
return fieldPointsToDynamicRecordOfLabels( node.getLabelField() )
? DynamicNodeLabels.get( node, nodeStore )
: InlineNodeLabels.get( node );
}
public static long[] get( NodeRecord node, RecordCursor<DynamicRecord> dynamicLabelCursor )
{
return fieldPointsToDynamicRecordOfLabels( node.getLabelField() )
? DynamicNodeLabels.get( node, dynamicLabelCursor )
: InlineNodeLabels.get( node );
}
public static boolean fieldPointsToDynamicRecordOfLabels( long labelField )
{
return (labelField & 0x8000000000L) != 0;
}
public static long parseLabelsBody( long labelField )
{
return labelField & 0xFFFFFFFFFL;
}
/**
* @see NodeRecord
*
* @param labelField label field value from a node record
* @return the id of the dynamic record this label field points to or null if it is an inline label field
*/
public static long firstDynamicLabelRecordId( long labelField )
{
assert fieldPointsToDynamicRecordOfLabels( labelField );
return parseLabelsBody( labelField );
}
/**
* Checks so that a label id array is sane, i.e. that it's sorted and contains no duplicates.
*/
public static boolean isSane( long[] labelIds )
{
long prev = -1;
for ( long labelId : labelIds )
{
if ( labelId <= prev )
{
return false;
}
prev = labelId;
}
return true;
}
}