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Diffstat (limited to 'cpp/src/qpid/legacystore/jrnl/rrfc.h')
| -rw-r--r-- | cpp/src/qpid/legacystore/jrnl/rrfc.h | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/cpp/src/qpid/legacystore/jrnl/rrfc.h b/cpp/src/qpid/legacystore/jrnl/rrfc.h new file mode 100644 index 0000000000..5066d6048a --- /dev/null +++ b/cpp/src/qpid/legacystore/jrnl/rrfc.h @@ -0,0 +1,179 @@ +/* + * + * 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 rrfc.h + * + * Qpid asynchronous store plugin library + * + * File containing code for class mrg::journal::rrfc (rotating + * file controller). See class documentation for details. + * + * \author Kim van der Riet + */ + +#ifndef QPID_LEGACYSTORE_JRNL_RRFC_H +#define QPID_LEGACYSTORE_JRNL_RRFC_H + +namespace mrg +{ +namespace journal +{ +class rrfc; +} +} + +#include "qpid/legacystore/jrnl/fcntl.h" +#include "qpid/legacystore/jrnl/rfc.h" + +namespace mrg +{ +namespace journal +{ + + /** + * \class rrfc + * \brief Read Rotating File Controller (rrfc) - Subclassed from pure virtual class rfc. Used to control the read + * pipeline in a rotating file buffer or journal. See class rfc for further details. + * + * The states that exist in this class are identical to class rfc from which it inherits, but in addition, the value + * of the read file handle _fh is also considered. The calls to set_findex also opens the file handle _fh to the + * active file for reading. Similarly, unset_findex() closes this file handle. + * + * <pre> + * is_init() is_active() + * +===+ _lpmp.is_init() == false + * +---------->| | Uninitialized: _curr_fc == 0 F F + * | +-->+===+ --+ _fh == -1 + * | | | + * | | | + * | finalize() initialize() + * | | | + * | | | + * | +-- +===+<--+ _lpmp.is_init() == true + * finalize() | | Inactive: _curr_fc == 0 T F + * | +-->+===+ --+ _fh == -1 + * | | | + * | | | + * | unset_findex() set_findex() + * | | | + * | | | + * | +-- +===+<--+ _lpmp.is_init() == true + * +---------- | | Active: _curr_fc != 0 T T + * +===+ _fh >= 0 + * </pre> + * + * In adition to the states above, class rrfc contains a validity flag. This is operated indepenedently of the state + * machine. This flag (_valid) indicates when the read buffers are valid for reading. This is not strictly a state, + * but simply a flag used to keep track of the status, and is set/unset with calls to set_valid() and set_invalid() + * respectively. + */ + class rrfc : public rfc + { + protected: + int _fh; ///< Read file handle + bool _valid; ///< Flag is true when read pages contain vailid data + + public: + rrfc(const lpmgr* lpmp); + virtual ~rrfc(); + + /** + * \brief Initialize the controller, moving from state Uninitialized to Initialized. The main function of + * initialize() is to set the number of files and the pointer to the fcntl array. + */ + inline void initialize() { rfc::initialize(); _valid = false; } + + /** + * \brief Reset the controller to Uninitialized state, usually called when the journal is stopped. Once called, + * initialize() must be called to reuse an instance. + */ + void finalize(); + + /** + * \brief Opens the file handle for reading a particular fid. Moves to state open. + */ + void set_findex(const u_int16_t fc_index); + + /** + * \brief Closes the read file handle and nulls the active fcntl pointer. Moves to state closed. + */ + void unset_findex(); + + /** + * \brief Check the state: true = open; false = closed. + */ + inline bool is_active() const { return _curr_fc != 0 && _fh >= 0; } + + /** + * \brief Sets the validity flag which indicates that the read buffers contain valid data for reading. + */ + inline void set_invalid() { _valid = false; } + + /** + * \brief Resets the validity flag wich indicates that the read buffers are no longer synchronized and cannot + * be read whithout resynchronization. + */ + inline void set_valid() { _valid = true; } + + /** + * \brief Checks the read buffer validity status: true = valid, can be read; false = invalid, synchronization + * required. + */ + inline bool is_valid() const { return _valid; } + + /** + * \brief Rotate active file controller to next file in rotating file group. + * \exception jerrno::JERR__NINIT if called before calling initialize(). + */ + iores rotate(); + + inline int fh() const { return _fh; } + + inline u_int32_t subm_cnt_dblks() const { return _curr_fc->rd_subm_cnt_dblks(); } + inline std::size_t subm_offs() const { return _curr_fc->rd_subm_offs(); } + inline u_int32_t add_subm_cnt_dblks(u_int32_t a) { return _curr_fc->add_rd_subm_cnt_dblks(a); } + + inline u_int32_t cmpl_cnt_dblks() const { return _curr_fc->rd_cmpl_cnt_dblks(); } + inline std::size_t cmpl_offs() const { return _curr_fc->rd_cmpl_offs(); } + inline u_int32_t add_cmpl_cnt_dblks(u_int32_t a) { return _curr_fc->add_rd_cmpl_cnt_dblks(a); } + + inline bool is_void() const { return _curr_fc->rd_void(); } + inline bool is_empty() const { return _curr_fc->rd_empty(); } + inline u_int32_t remaining_dblks() const { return _curr_fc->rd_remaining_dblks(); } + inline bool is_full() const { return _curr_fc->is_rd_full(); } + inline bool is_compl() const { return _curr_fc->is_rd_compl(); } + inline u_int32_t aio_outstanding_dblks() const { return _curr_fc->rd_aio_outstanding_dblks(); } + inline bool file_rotate() const { return _curr_fc->rd_file_rotate(); } + inline bool is_wr_aio_outstanding() const { return _curr_fc->wr_aio_outstanding_dblks() > 0; } + + // Debug aid + std::string status_str() const; + + protected: + void open_fh(const std::string& fn); + void close_fh(); + }; // class rrfc + +} // namespace journal +} // namespace mrg + +#endif // ifndef QPID_LEGACYSTORE_JRNL_RRFC_H |