expression_parser.h

/**
 *    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 <boost/none.hpp>
#include <boost/optional/optional.hpp>
#include <boost/smart_ptr/intrusive_ptr.hpp>
#include <functional>
#include <limits>
#include <memory>

#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonelement.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/matcher/expression_leaf.h"
#include "mongo/db/matcher/expression_tree.h"
#include "mongo/db/matcher/expression_type.h"
#include "mongo/db/matcher/expression_with_placeholder.h"
#include "mongo/db/matcher/extensions_callback.h"
#include "mongo/db/matcher/extensions_callback_noop.h"
#include "mongo/db/matcher/schema/expression_internal_schema_allowed_properties.h"
#include "mongo/db/pipeline/expression.h"
#include "mongo/db/pipeline/expression_context.h"

namespace mongo {

class OperationContext;

enum class PathAcceptingKeyword {
    ALL,
    BITS_ALL_CLEAR,
    BITS_ALL_SET,
    BITS_ANY_CLEAR,
    BITS_ANY_SET,
    ELEM_MATCH,
    EQUALITY,
    EXISTS,
    GEO_INTERSECTS,
    GEO_NEAR,
    GREATER_THAN,
    GREATER_THAN_OR_EQUAL,
    INTERNAL_EXPR_EQ,
    INTERNAL_EXPR_GT,
    INTERNAL_EXPR_GTE,
    INTERNAL_EXPR_LT,
    INTERNAL_EXPR_LTE,
    INTERNAL_EQ_HASHED_KEY,
    INTERNAL_SCHEMA_ALL_ELEM_MATCH_FROM_INDEX,
    INTERNAL_SCHEMA_BIN_DATA_ENCRYPTED_TYPE,
    INTERNAL_SCHEMA_BIN_DATA_SUBTYPE,
    INTERNAL_SCHEMA_EQ,
    INTERNAL_SCHEMA_FMOD,
    INTERNAL_SCHEMA_MATCH_ARRAY_INDEX,
    INTERNAL_SCHEMA_MAX_ITEMS,
    INTERNAL_SCHEMA_MAX_LENGTH,
    INTERNAL_SCHEMA_MIN_ITEMS,
    INTERNAL_SCHEMA_MIN_LENGTH,
    INTERNAL_SCHEMA_OBJECT_MATCH,
    INTERNAL_SCHEMA_TYPE,
    INTERNAL_SCHEMA_UNIQUE_ITEMS,
    IN_EXPR,
    LESS_THAN,
    LESS_THAN_OR_EQUAL,
    MOD,
    NOT_EQUAL,
    NOT_IN,
    OPTIONS,
    REGEX,
    SIZE,
    TYPE,
    WITHIN,
};

class MatchExpressionParser {
public:
    /**
     * Features allowed in match expression parsing.
     */
    enum AllowedFeatures {
        kText = 1,
        kGeoNear = 1 << 1,
        kJavascript = 1 << 2,
        kExpr = 1 << 3,
        kJSONSchema = 1 << 4,
        kEncryptKeywords = 1 << 5,
    };
    using AllowedFeatureSet = unsigned long long;
    static constexpr AllowedFeatureSet kBanAllSpecialFeatures = 0;
    static constexpr AllowedFeatureSet kAllowAllSpecialFeatures =
        std::numeric_limits<unsigned long long>::max();
    static constexpr AllowedFeatureSet kDefaultSpecialFeatures =
        AllowedFeatures::kExpr | AllowedFeatures::kJSONSchema | AllowedFeatures::kEncryptKeywords;

    /**
     * Parses PathAcceptingKeyword from 'typeElem'. Returns 'defaultKeyword' if 'typeElem'
     * doesn't represent a known type.
     */
    static boost::optional<PathAcceptingKeyword> parsePathAcceptingKeyword(
        BSONElement typeElem, boost::optional<PathAcceptingKeyword> defaultKeyword = boost::none);

    /**
     * Caller has to maintain ownership of 'obj'.
     * The tree has views (BSONElement) into 'obj'.
     */
    static StatusWithMatchExpression parse(
        const BSONObj& obj,
        const boost::intrusive_ptr<ExpressionContext>& expCtx,
        const ExtensionsCallback& extensionsCallback = ExtensionsCallbackNoop(),
        AllowedFeatureSet allowedFeatures = kDefaultSpecialFeatures);

    /**
     * Parse the given MatchExpression and normalize the resulting tree by optimizing and then
     * sorting it. Throws if the given BSONObj fails to parse.
     */
    static std::unique_ptr<MatchExpression> parseAndNormalize(
        const BSONObj& obj,
        const boost::intrusive_ptr<ExpressionContext>& expCtx,
        const ExtensionsCallback& extensionsCallback = ExtensionsCallbackNoop(),
        AllowedFeatureSet allowedFeatures = kDefaultSpecialFeatures);
};
}  // namespace mongo