/*
 *
 * 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.
 *
 */

/**
 * \file fcntl.h
 *
 * Qpid asynchronous store plugin library
 *
 * File containing code for class mrg::journal::fcntl (non-logging file
 * handle), used for controlling journal log files. See class documentation for
 * details.
 *
 * \author Kim van der Riet
 */

#ifndef QPID_LEGACYSTORE_JRNL_FCNTL_H
#define QPID_LEGACYSTORE_JRNL_FCNTL_H

namespace mrg
{
namespace journal
{
class fcntl;
}
}

#include <cstddef>
#include <string>
#include "qpid/legacystore/jrnl/rcvdat.h"
#include <sys/types.h>

namespace mrg
{
namespace journal
{

    /**
    * \class fcntl
    * \brief Journal file controller. There is one instance per journal file.
    */
    class fcntl
    {
    protected:
        std::string _fname;             ///< File name
        u_int16_t _pfid;                ///< Physical file ID (file number in order of creation)
        u_int16_t _lfid;                ///< Logical file ID (ordinal number in ring store)
        const u_int32_t _ffull_dblks;   ///< File size in dblks (incl. file header)
        int _wr_fh;                     ///< Write file handle
        u_int32_t _rec_enqcnt;          ///< Count of enqueued records
        u_int32_t _rd_subm_cnt_dblks;   ///< Read file count (data blocks) for submitted AIO
        u_int32_t _rd_cmpl_cnt_dblks;   ///< Read file count (data blocks) for completed AIO
        u_int32_t _wr_subm_cnt_dblks;   ///< Write file count (data blocks) for submitted AIO
        u_int32_t _wr_cmpl_cnt_dblks;   ///< Write file count (data blocks) for completed AIO
        u_int16_t _aio_cnt;             ///< Outstanding AIO operations on this file
        bool _fhdr_wr_aio_outstanding;  ///< Outstanding file header write on this file

    public:
        // Constructors with implicit initialize() and open()
        fcntl(const std::string& fbasename, const u_int16_t pfid, const u_int16_t lfid, const u_int32_t jfsize_sblks,
                const rcvdat* const ro);
        virtual ~fcntl();

        virtual bool reset(const rcvdat* const ro = 0);
        virtual void rd_reset();
        virtual bool wr_reset(const rcvdat* const ro = 0);

        virtual int open_wr_fh();
        virtual void close_wr_fh();
        inline bool is_wr_fh_open() const { return _wr_fh >= 0; }

        inline const std::string& fname() const { return _fname; }
        inline u_int16_t pfid() const { return _pfid; }
        inline u_int16_t lfid() const { return _lfid; }
        inline void set_lfid(const u_int16_t lfid) { _lfid = lfid; }
        inline int wr_fh() const { return _wr_fh; }
        inline u_int32_t enqcnt() const { return _rec_enqcnt; }
        inline u_int32_t incr_enqcnt() { return ++_rec_enqcnt; }
        u_int32_t add_enqcnt(u_int32_t a);
        u_int32_t decr_enqcnt();
        u_int32_t subtr_enqcnt(u_int32_t s);

        inline u_int32_t rd_subm_cnt_dblks() const { return _rd_subm_cnt_dblks; }
        inline std::size_t rd_subm_offs() const { return _rd_subm_cnt_dblks * JRNL_DBLK_SIZE; }
        u_int32_t add_rd_subm_cnt_dblks(u_int32_t a);

        inline u_int32_t rd_cmpl_cnt_dblks() const { return _rd_cmpl_cnt_dblks; }
        inline std::size_t rd_cmpl_offs() const { return _rd_cmpl_cnt_dblks * JRNL_DBLK_SIZE; }
        u_int32_t add_rd_cmpl_cnt_dblks(u_int32_t a);

        inline u_int32_t wr_subm_cnt_dblks() const { return _wr_subm_cnt_dblks; }
        inline std::size_t wr_subm_offs() const { return _wr_subm_cnt_dblks * JRNL_DBLK_SIZE; }
        u_int32_t add_wr_subm_cnt_dblks(u_int32_t a);

        inline u_int32_t wr_cmpl_cnt_dblks() const { return _wr_cmpl_cnt_dblks; }
        inline std::size_t wr_cmpl_offs() const { return _wr_cmpl_cnt_dblks * JRNL_DBLK_SIZE; }
        u_int32_t add_wr_cmpl_cnt_dblks(u_int32_t a);

        inline u_int16_t aio_cnt() const { return _aio_cnt; }
        inline u_int16_t incr_aio_cnt() { return ++_aio_cnt; }
        u_int16_t decr_aio_cnt();

        inline bool wr_fhdr_aio_outstanding() { return _fhdr_wr_aio_outstanding; }
        inline void set_wr_fhdr_aio_outstanding(const bool wfao) { _fhdr_wr_aio_outstanding = wfao; }

        // Derived helper functions

        inline bool rd_void() const { return _wr_cmpl_cnt_dblks == 0; }
        inline bool rd_empty() const { return _wr_cmpl_cnt_dblks <= JRNL_SBLK_SIZE; }
        inline u_int32_t rd_remaining_dblks() const { return _wr_cmpl_cnt_dblks - _rd_subm_cnt_dblks; }
        inline bool is_rd_full() const { return _wr_cmpl_cnt_dblks == _rd_subm_cnt_dblks; }
        inline bool is_rd_compl() const { return _wr_cmpl_cnt_dblks == _rd_cmpl_cnt_dblks; }
        inline u_int32_t rd_aio_outstanding_dblks() const { return _rd_subm_cnt_dblks - _rd_cmpl_cnt_dblks; }
        inline bool rd_file_rotate() const { return is_rd_full() && is_wr_compl(); }

        inline bool wr_void() const { return _wr_subm_cnt_dblks == 0; }
        inline bool wr_empty() const { return _wr_subm_cnt_dblks <= JRNL_SBLK_SIZE; }
        inline u_int32_t wr_remaining_dblks() const { return _ffull_dblks - _wr_subm_cnt_dblks; }
        inline bool is_wr_full() const { return _ffull_dblks == _wr_subm_cnt_dblks; }
        inline bool is_wr_compl() const { return _ffull_dblks == _wr_cmpl_cnt_dblks; }
        inline u_int32_t wr_aio_outstanding_dblks() const { return _wr_subm_cnt_dblks - _wr_cmpl_cnt_dblks; }
        inline bool wr_file_rotate() const { return is_wr_full(); }

        // Debug aid
        const std::string status_str() const;

    protected:
        virtual void initialize(const std::string& fbasename, const u_int16_t pfid, const u_int16_t lfid,
                const u_int32_t jfsize_sblks, const rcvdat* const ro);

        static std::string filename(const std::string& fbasename, const u_int16_t pfid);
        void clean_file(const u_int32_t jfsize_sblks);
        void create_jfile(const u_int32_t jfsize_sblks);
    };

} // namespace journal
} // namespace mrg

#endif // ifndef QPID_LEGACYSTORE_JRNL_FCNTL_H