cql_statement.hh

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Copyright (C) 2014-present ScyllaDB
 *
 * Modified by ScyllaDB
 */

/*
 * This file is part of Scylla.
 *
 * Scylla is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Scylla 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 Scylla.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "timeout_config.hh"

namespace service {

class storage_proxy;
class query_state;
class client_state;

}

namespace cql_transport {

namespace messages {

class result_message;

}

}

namespace cql3 {

class query_processor;

class metadata;
seastar::shared_ptr<const metadata> make_empty_metadata();

class query_options;

class cql_statement {
    timeout_config_selector _timeout_config_selector;
public:
    // CQL statement text
    seastar::sstring raw_cql_statement;

    explicit cql_statement(timeout_config_selector timeout_selector) : _timeout_config_selector(timeout_selector) {}

    virtual ~cql_statement()
    { }

    timeout_config_selector get_timeout_config_selector() const { return _timeout_config_selector; }

    virtual uint32_t get_bound_terms() const = 0;

    /**
     * Perform any access verification necessary for the statement.
     *
     * @param state the current client state
     */
    virtual seastar::future<> check_access(service::storage_proxy& proxy, const service::client_state& state) const = 0;

    /**
     * Perform additional validation required by the statment.
     * To be overriden by subclasses if needed.
     *
     * @param state the current client state
     */
    virtual void validate(service::storage_proxy& proxy, const service::client_state& state) const = 0;

    /**
     * Execute the statement and return the resulting result or null if there is no result.
     *
     * @param state the current query state
     * @param options options for this query (consistency, variables, pageSize, ...)
     */
    virtual seastar::future<seastar::shared_ptr<cql_transport::messages::result_message>>
        execute(query_processor& qp, service::query_state& state, const query_options& options) const = 0;

    virtual bool depends_on_keyspace(const seastar::sstring& ks_name) const = 0;

    virtual bool depends_on_column_family(const seastar::sstring& cf_name) const = 0;

    virtual seastar::shared_ptr<const metadata> get_result_metadata() const = 0;

    virtual bool is_conditional() const {
        return false;
    }
};

class cql_statement_no_metadata : public cql_statement {
public:
    using cql_statement::cql_statement;
    virtual seastar::shared_ptr<const metadata> get_result_metadata() const override {
        return make_empty_metadata();
    }
};

// Conditional modification statements and batches
// return a result set and have metadata, while same
// statements without conditions do not.
class cql_statement_opt_metadata : public cql_statement {
protected:
    // Result set metadata, may be empty for simple updates and batches
    seastar::shared_ptr<metadata> _metadata;
public:
    using cql_statement::cql_statement;
    virtual seastar::shared_ptr<const metadata> get_result_metadata() const override {
        if (_metadata) {
            return _metadata;
        }
        return make_empty_metadata();
    }
};

}