diff options
Diffstat (limited to 'cpp/src/qpid/legacystore/jrnl/file_hdr.h')
| -rw-r--r-- | cpp/src/qpid/legacystore/jrnl/file_hdr.h | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/cpp/src/qpid/legacystore/jrnl/file_hdr.h b/cpp/src/qpid/legacystore/jrnl/file_hdr.h new file mode 100644 index 0000000000..db20834cbb --- /dev/null +++ b/cpp/src/qpid/legacystore/jrnl/file_hdr.h @@ -0,0 +1,211 @@ +/* + * + * 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 file_hdr.h + * + * Qpid asynchronous store plugin library + * + * File containing code for class mrg::journal::file_hdr (file + * record header), used to start a journal file. It contains some + * file metadata and information to aid journal recovery. + * + * \author Kim van der Riet + */ + +#ifndef QPID_LEGACYSTORE_JRNL_FILE_HDR_H +#define QPID_LEGACYSTORE_JRNL_FILE_HDR_H + +#include <cerrno> +#include <ctime> +#include "qpid/legacystore/jrnl/rec_hdr.h" +#include "qpid/legacystore/jrnl/jerrno.h" +#include "qpid/legacystore/jrnl/jexception.h" +#include <sstream> + +namespace mrg +{ +namespace journal +{ + +#pragma pack(1) + + /** + * \brief Struct for data common to the head of all journal files. In addition to + * the common data, this includes the record ID and offset of the first record in + * the file. + * + * This header precedes all data in journal files and occupies the first complete + * block in the file. The record ID and offset are updated on each overwrite of the + * file. + * + * File header info in binary format (48 bytes): + * <pre> + * 0 7 + * +---+---+---+---+---+---+---+---+ -+ + * | magic | v | e | flags | | + * +---+---+---+---+---+---+---+---+ | struct hdr + * | first rid in file | | + * +---+---+---+---+---+---+---+---+ -+ + * | pfid | lfid | reserved (0) | + * +---+---+---+---+---+---+---+---+ + * | fro | + * +---+---+---+---+---+---+---+---+ + * | timestamp (sec) | + * +---+---+---+---+---+---+---+---+ + * | timestamp (ns) | + * +---+---+---+---+---+---+---+---+ + * v = file version (If the format or encoding of this file changes, then this + * number should be incremented) + * e = endian flag, false (0x00) for little endian, true (0x01) for big endian + * pfid = File ID (number used in naming file) + * lfid = Logical ID (order used in circular buffer) + * fro = First record offset, offset from start of file to first record header + * </pre> + * + * Note that journal files should be transferable between 32- and 64-bit + * hardware of the same endianness, but not between hardware of opposite + * entianness without some sort of binary conversion utility. Thus buffering + * will be needed for types that change size between 32- and 64-bit compiles. + */ + struct file_hdr : rec_hdr + { + u_int16_t _pfid; ///< Physical file ID (pfid) + u_int16_t _lfid; ///< Logical file ID (lfid) + u_int32_t _res; ///< Reserved (for alignment/flags) +#if defined(JRNL_BIG_ENDIAN) && defined(JRNL_32_BIT) + u_int32_t _filler0; ///< Big-endian filler for 32-bit size_t +#endif + std::size_t _fro; ///< First record offset +#if defined(JRNL_LITTLE_ENDIAN) && defined(JRNL_32_BIT) + u_int32_t _filler0; ///< Little-endian filler for 32-bit size_t +#endif +#if defined(JRNL_BIG_ENDIAN) && defined(JRNL_32_BIT) + u_int32_t _filler1; ///< Big-endian filler for 32-bit time_t +#endif + std::time_t _ts_sec; ///< Timestamp of journal initilailization +#if defined(JRNL_LITTLE_ENDIAN) && defined(JRNL_32_BIT) + u_int32_t _filler1; ///< Little-endian filler for 32-bit time_t +#endif +#if defined(JRNL_BIG_ENDIAN) + u_int32_t _filler2; ///< Big endian filler for u_int32_t +#endif + u_int32_t _ts_nsec; ///< Timestamp of journal initilailization +#if defined(JRNL_LITTLE_ENDIAN) + u_int32_t _filler2; ///< Little-endian filler for u_int32_t +#endif + + /** + * \brief Default constructor, which sets all values to 0. + */ + inline file_hdr(): rec_hdr(), _pfid(0), _lfid(0), _res(0), +#if defined(JRNL_BIG_ENDIAN) && defined(JRNL_32_BIT) + _filler0(0), +#endif + _fro(0), +#if defined(JRNL_LITTLE_ENDIAN) && defined(JRNL_32_BIT) + _filler0(0), +#endif +#if defined(JRNL_BIG_ENDIAN) && defined(JRNL_32_BIT) + _filler1(0), +#endif + _ts_sec(0), +#if defined(JRNL_LITTLE_ENDIAN) && defined(JRNL_32_BIT) + _filler1(0), +#endif +#if defined(JRNL_BIG_ENDIAN) + _filler2(0), +#endif + _ts_nsec(0) +#if defined(JRNL_LITTLE_ENDIAN) + , _filler2(0) +#endif + {} + + /** + * \brief Convenience constructor which initializes values during construction. + */ + inline file_hdr(const u_int32_t magic, const u_int8_t version, const u_int64_t rid, + const u_int16_t pfid, const u_int16_t lfid, const std::size_t fro, + const bool owi, const bool settime = false): + rec_hdr(magic, version, rid, owi), _pfid(pfid), _lfid(lfid), _res(0), +#if defined(JRNL_BIG_ENDIAN) && defined(JRNL_32_BIT) + _filler0(0), +#endif + _fro(fro), +#if defined(JRNL_LITTLE_ENDIAN) && defined(JRNL_32_BIT) + _filler0(0), +#endif +#if defined(JRNL_BIG_ENDIAN) && defined(JRNL_32_BIT) + _filler1(0), +#endif + _ts_sec(0), +#if defined(JRNL_LITTLE_ENDIAN) && defined(JRNL_32_BIT) + _filler1(0), +#endif +#if defined(JRNL_BIG_ENDIAN) + _filler2(0), +#endif + _ts_nsec(0) +#if defined(JRNL_LITTLE_ENDIAN) + , _filler2(0) +#endif + { if (settime) set_time(); } + + /** + * \brief Gets the current time from the system clock and sets the timestamp in the struct. + */ + inline void set_time() + { + // TODO: Standardize on method for getting time that does not requrie a context switch. + timespec ts; + if (::clock_gettime(CLOCK_REALTIME, &ts)) + { + std::ostringstream oss; + oss << FORMAT_SYSERR(errno); + throw jexception(jerrno::JERR__RTCLOCK, oss.str(), "file_hdr", "set_time"); + } + _ts_sec = ts.tv_sec; + _ts_nsec = ts.tv_nsec; + } + + /** + * \brief Sets the timestamp in the struct to the provided value (in seconds and + * nanoseconds). + */ + inline void set_time(timespec& ts) + { + _ts_sec = ts.tv_sec; + _ts_nsec = ts.tv_nsec; + } + + /** + * \brief Returns the size of the header in bytes. + */ + inline static std::size_t size() { return sizeof(file_hdr); } + }; // struct file_hdr + +#pragma pack() + +} // namespace journal +} // namespace mrg + +#endif // ifndef QPID_LEGACYSTORE_JRNL_FILE_HDR_H |