db_high_priority_service.hpp

/*
 * Copyright (C) 2018-2019 Codership Oy <info@codership.com>
 *
 * This file is part of wsrep-lib.
 *
 * Wsrep-lib 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 2 of the License, or
 * (at your option) any later version.
 *
 * Wsrep-lib 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 wsrep-lib.  If not, see <https://www.gnu.org/licenses/>.
 */

#ifndef WSREP_DB_HIGH_PRIORITY_SERVICE_HPP
#define WSREP_DB_HIGH_PRIORITY_SERVICE_HPP

#include "wsrep/high_priority_service.hpp"

namespace db
{
    class server;
    class client;
    class high_priority_service : public wsrep::high_priority_service
    {
    public:
        high_priority_service(db::server& server, db::client& client);
        int start_transaction(const wsrep::ws_handle&,
                              const wsrep::ws_meta&) override;
        int next_fragment(const wsrep::ws_meta&) override;
        const wsrep::transaction& transaction() const override;
        int adopt_transaction(const wsrep::transaction&) override;
        int apply_write_set(const wsrep::ws_meta&,
                            const wsrep::const_buffer&,
                            wsrep::mutable_buffer&) override;
        int append_fragment_and_commit(
            const wsrep::ws_handle&,
            const wsrep::ws_meta&,
            const wsrep::const_buffer&,
            int,
            const wsrep::xid&) override
        { return 0; }
        int remove_fragments(const wsrep::ws_meta&) override
        { return 0; }
        int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) override;
      int rollback(const wsrep::ws_handle&, const wsrep::ws_meta&,
                   bool skip_rollback = false) override;
        int apply_toi(const wsrep::ws_meta&, const wsrep::const_buffer&,
                      wsrep::mutable_buffer&) override;
        int apply_nbo_begin(const wsrep::ws_meta&, const wsrep::const_buffer&,
                            wsrep::mutable_buffer&)
            override;
        void adopt_apply_error(wsrep::mutable_buffer&) override;
        virtual void after_apply() override;
        void store_globals() override { }
        void reset_globals() override { }
        void switch_execution_context(wsrep::high_priority_service&) override
        { }
        int log_dummy_write_set(const wsrep::ws_handle&,
                                const wsrep::ws_meta&,
                                wsrep::mutable_buffer&) override;
        virtual bool is_replaying() const override;
        void debug_crash(const char*) override { }
    private:
        high_priority_service(const high_priority_service&);
        high_priority_service& operator=(const high_priority_service&);
        db::server& server_;
        db::client& client_;
    };

    class replayer_service : public db::high_priority_service
    {
    public:
        replayer_service(db::server& server, db::client& client)
            : db::high_priority_service(server, client)
        { }
        // After apply is empty for replayer to keep the transaction
        // context available for the client session after replaying
        // is over.
        void after_apply() override {}
        bool is_replaying() const override { return true; }
    };

}

#endif // WSREP_DB_HIGH_PRIORITY_SERVICE_HPP