//
// Copyright (C) 2018 Codership Oy <info@codership.com>
//

/** @file storage_service.hpp
 *
 * Abstract interface which defines required access to DBMS storage
 * service. The service is used for storing streaming replication
 * write set fragments into stable storage. The interface is used
 * from locally processing transaction context only. Corresponding
 * operations for high priority processing can be found from
 * wsrep::high_priority_service interface.
 */
#ifndef WSREP_STORAGE_SERVICE_HPP
#define WSREP_STORAGE_SERVICE_HPP

#include "transaction_id.hpp"
#include "id.hpp"
#include "buffer.hpp"

namespace wsrep
{
    // Forward declarations
    class ws_handle;
    class ws_meta;
    class transaction;

    /**
     * Storage service abstract interface.
     */
    class storage_service
    {
    public:
        virtual ~storage_service() { }
        /**
         * Start a new transaction for storage access.
         *
         * @param[out] ws_handle Write set handle for a new transaction
         *
         * @return Zero in case of success, non-zero on error.
         */
        virtual int start_transaction(const wsrep::ws_handle&) = 0;

        virtual void adopt_transaction(const wsrep::transaction&) = 0;
        /**
         * Append fragment into stable storage.
         */
        virtual int append_fragment(const wsrep::id& server_id,
                                    wsrep::transaction_id client_id,
                                    int flags,
                                    const wsrep::const_buffer& data) = 0;

        /**
         * Update fragment meta data after certification process.
         */
        virtual int update_fragment_meta(const wsrep::ws_meta&) = 0;

        /**
         * Commit the transaction.
         */
        virtual int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) = 0;

        /**
         * Roll back the transaction.
         */
        virtual int rollback(const wsrep::ws_handle&,
                             const wsrep::ws_meta&) = 0;


        virtual void store_globals() = 0;
        virtual void reset_globals() = 0;
    };
}

#endif // WSREP_STORAGE_SERVICE_HPP