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/*
*
* 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
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