/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    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
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#pragma once

#include "mongo/db/query/canonical_query.h"

namespace mongo {

/**
 * Returns true if the query predicate involves a negation of an EQ, LTE, or GTE comparison to
 * 'null'.
 */
bool isQueryNegatingEqualToNull(const mongo::MatchExpression* tree);


namespace canonical_query_encoder {
/**
 * Encode the given CanonicalQuery into a string representation which represents the shape of the
 * query. This is done by encoding the match, projection and sort and stripping the values from the
 * match. Two queries with the same shape may not necessarily be able to use the same plan, so the
 * plan cache has to add information to discriminate between queries with the same shape.
 */
CanonicalQuery::QueryShapeString encode(const CanonicalQuery& cq);

/**
 * Encode the given CanonicalQuery into a string representation which represents the shape of the
 * query for SBE plans. This is done by encoding the match, projection, sort and the FindCommand.
 * Two queries with the same shape may not necessarily be able to use the same plan, so the
 * plan cache has to add information to discriminate between queries with the same shape.
 */
CanonicalQuery::QueryShapeString encodeSBE(const CanonicalQuery& cq);

/**
 * Returns a hash of the given key (produced from either a QueryShapeString or a PlanCacheKey).
 */
uint32_t computeHash(StringData key);
}  // namespace canonical_query_encoder
}  // namespace mongo