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Neo4j kernel is a lightweight, embedded Java database designed to store data structured as graphs rather than tables. For more information, see http://neo4j.org.

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/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.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 .
 */
package org.neo4j.kernel.impl.newapi;

import org.eclipse.collections.api.iterator.LongIterator;
import org.eclipse.collections.api.set.primitive.LongSet;
import org.eclipse.collections.impl.factory.primitive.LongSets;

import org.neo4j.internal.kernel.api.NodeLabelIndexCursor;
import org.neo4j.internal.kernel.api.security.AccessMode;
import org.neo4j.io.pagecache.context.CursorContext;
import org.neo4j.kernel.api.index.IndexProgressor;
import org.neo4j.kernel.api.txstate.TransactionState;
import org.neo4j.kernel.impl.index.schema.TokenScan;

import static org.neo4j.collection.PrimitiveLongCollections.mergeToSet;

class NodeLabelIndexCursorScan extends BaseCursorScan
{
    private final LongSet removed;
    private final int label;

    NodeLabelIndexCursorScan( Read read, int label, TokenScan tokenScan )
    {
        super( tokenScan, read, () -> read.txState().nodesWithLabelChanged( label ).getAdded().toArray() );
        this.label = label;
        if ( hasChanges )
        {
            TransactionState txState = read.txState();
            this.removed = mergeToSet( txState.addedAndRemovedNodes().getRemoved(),
                    txState.nodesWithLabelChanged( label ).getRemoved() );
        }
        else
        {
            this.removed = LongSets.immutable.empty();
        }
    }

    @Override
    protected boolean scanStore( NodeLabelIndexCursor cursor, int sizeHint, LongIterator addedItems, CursorContext cursorContext, AccessMode accessMode )
    {
        DefaultNodeLabelIndexCursor indexCursor = (DefaultNodeLabelIndexCursor) cursor;
        indexCursor.setRead( read );
        IndexProgressor indexProgressor = storageScan.initializeBatch( indexCursor, sizeHint, cursorContext );

        if ( indexProgressor == IndexProgressor.EMPTY && !addedItems.hasNext() )
        {
            return false;
        }
        else
        {
            indexCursor.initialize( indexProgressor, label, addedItems, removed, accessMode );
            return true;
        }
    }
}