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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 [https://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 static org.neo4j.collection.PrimitiveLongCollections.mergeToSet;

import org.eclipse.collections.api.set.primitive.LongSet;
import org.neo4j.internal.kernel.api.KernelReadTracer;
import org.neo4j.internal.kernel.api.NodeCursor;
import org.neo4j.internal.kernel.api.NodeValueIndexCursor;
import org.neo4j.internal.kernel.api.PropertyIndexQuery;
import org.neo4j.internal.kernel.api.security.AccessMode;
import org.neo4j.internal.schema.IndexDescriptor;
import org.neo4j.kernel.api.txstate.TransactionState;
import org.neo4j.storageengine.api.PropertySelection;

class DefaultNodeValueIndexCursor extends DefaultEntityValueIndexCursor
        implements NodeValueIndexCursor {
    private final InternalCursorFactory internalCursors;
    private final boolean applyAccessModeToTxState;
    private DefaultNodeCursor securityNodeCursor;
    private DefaultPropertyCursor securityPropertyCursor;
    private int[] propertyIds;

    DefaultNodeValueIndexCursor(
            CursorPool pool,
            InternalCursorFactory internalCursors,
            boolean applyAccessModeToTxState) {
        super(pool, applyAccessModeToTxState);
        this.internalCursors = internalCursors;
        this.applyAccessModeToTxState = applyAccessModeToTxState;
    }

    /**
     * Check that the user is allowed to access all nodes and properties given by the index descriptor.
     * 
     * If the current user is allowed to traverse all labels used in this index and read the properties
     * of all nodes in the index, we can skip checking on every node we get back.
     */
    @Override
    protected boolean canAccessAllDescribedEntities(IndexDescriptor descriptor) {
        propertyIds = descriptor.schema().getPropertyIds();
        int[] labelIds = descriptor.schema().getEntityTokenIds();
        AccessMode accessMode = read.getAccessMode();

        for (int label : labelIds) {
            /*
             * If there can be nodes in the index that that are disallowed to traverse,
             * post-filtering is needed.
             */
            if (!accessMode.allowsTraverseAllNodesWithLabel(label)) {
                return false;
            }
        }

        for (int propId : propertyIds) {
            /*
             * If reading the property is denied for some label,
             * there can be property values in the index that are disallowed,
             * so post-filtering is needed.
             */
            if (accessMode.disallowsReadPropertyForSomeLabel(propId)) {
                return false;
            }

            /*
             * If reading the property is not granted for all labels of the the index,
             * there can be property values in the index that are disallowed,
             * so post-filtering is needed.
             */
            for (int label : labelIds) {
                if (!accessMode.allowsReadNodeProperty(() -> Labels.from(label), propId)) {
                    return false;
                }
            }
        }
        return true;
    }

    @Override
    void traceOnEntity(KernelReadTracer tracer, long entity) {
        tracer.onNode(entity);
    }

    @Override
    String implementationName() {
        return "NodeValueIndexCursor";
    }

    @Override
    protected final boolean canAccessEntityAndProperties(long reference) {
        ensureSecurityNodeCursor();
        readEntity(read -> read.singleNode(reference, securityNodeCursor));
        if (!securityNodeCursor.next()) {
            // This node is not visible to this security context
            return false;
        }

        int[] labels = applyAccessModeToTxState
                ? securityNodeCursor.labels().all()
                : securityNodeCursor.labelsIgnoringTxStateSetRemove().all();

        AccessMode accessMode = read.getAccessMode();
        if (accessMode.hasPropertyReadRules(propertyIds)) {
            ensureSecurityPropertyCursor();
            securityNodeCursor.properties(securityPropertyCursor, PropertySelection.selection(propertyIds));
            return securityPropertyCursor.allowed(propertyIds, labels);
        } else {
            return accessMode.allowsReadNodeProperties(() -> Labels.from(labels), propertyIds);
        }
    }

    @Override
    public void node(NodeCursor cursor) {
        readEntity(read -> read.singleNode(entityReference(), cursor));
    }

    @Override
    public long nodeReference() {
        return entityReference();
    }

    @Override
    protected LongSet removed(TransactionState txState, LongSet removedFromIndex) {
        return mergeToSet(txState.addedAndRemovedNodes().getRemoved(), removedFromIndex)
                .asUnmodifiable();
    }

    @Override
    public void release() {
        if (securityNodeCursor != null) {
            securityNodeCursor.close();
            securityNodeCursor.release();
            securityNodeCursor = null;
        }
        if (securityPropertyCursor != null) {
            securityPropertyCursor.close();
            securityPropertyCursor.release();
            securityPropertyCursor = null;
        }
    }

    @Override
    protected boolean doStoreValuePassesQueryFilter(
            long reference, PropertySelection propertySelection, PropertyIndexQuery[] query) {
        ensureSecurityNodeCursor();
        read.singleNode(reference, securityNodeCursor);
        if (securityNodeCursor.next()) {
            ensureSecurityPropertyCursor();
            securityNodeCursor.properties(securityPropertyCursor, propertySelection);
            return CursorPredicates.propertiesMatch(securityPropertyCursor, query);
        }
        return false;
    }

    private void ensureSecurityNodeCursor() {
        if (securityNodeCursor == null) {
            securityNodeCursor = internalCursors.allocateNodeCursor();
        }
    }

    private void ensureSecurityPropertyCursor() {
        if (securityPropertyCursor == null) {
            securityPropertyCursor = internalCursors.allocatePropertyCursor();
        }
    }
}