src/qpid/linearstore/journal/txn_rec.cpp - qpid-cpp - Git at Google

 /*
  *
  * 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.
  *
  */

 #include "qpid/linearstore/journal/txn_rec.h"

 #include <cassert>
 #include <cstring>
 #include "qpid/linearstore/journal/Checksum.h"
 #include "qpid/linearstore/journal/jexception.h"

 namespace qpid {
 namespace linearstore {
 namespace journal {

 txn_rec::txn_rec():
         _xidp(0),
         _xid_buff(0)
 {
     ::txn_hdr_init(&_txn_hdr, 0, QLS_JRNL_VERSION, 0, 0, 0, 0);
     ::rec_tail_init(&_txn_tail, 0, 0, 0, 0);
 }

 txn_rec::~txn_rec()
 {
     clean();
 }

 void
 txn_rec::reset(const bool commitFlag, const uint64_t serial, const  uint64_t rid, const void* const xidp,
         const std::size_t xidlen)
 {
     _txn_hdr._rhdr._magic = commitFlag ? QLS_TXC_MAGIC : QLS_TXA_MAGIC;
     _txn_hdr._rhdr._serial = serial;
     _txn_hdr._rhdr._rid = rid;
     _txn_hdr._xidsize = xidlen;
     _xidp = xidp;
     _xid_buff = 0;
     _txn_tail._xmagic = ~_txn_hdr._rhdr._magic;
     _txn_tail._serial = serial;
     _txn_tail._rid = rid;
     _txn_tail._checksum = 0UL;
 }

 uint32_t
 txn_rec::encode(void* wptr, uint32_t rec_offs_dblks, uint32_t max_size_dblks, Checksum& checksum)
 {
     assert(wptr != 0);
     assert(max_size_dblks > 0);
     assert(_xidp != 0 && _txn_hdr._xidsize > 0);

     std::size_t rec_offs = rec_offs_dblks * QLS_DBLK_SIZE_BYTES;
     std::size_t rem = max_size_dblks * QLS_DBLK_SIZE_BYTES;
     std::size_t wr_cnt = 0;
     if (rec_offs_dblks) // Continuation of split dequeue record (over 2 or more pages)
     {
         if (size_dblks(rec_size()) - rec_offs_dblks > max_size_dblks) // Further split required
         {
             rec_offs -= sizeof(txn_hdr_t);
             std::size_t wsize = _txn_hdr._xidsize > rec_offs ? _txn_hdr._xidsize - rec_offs : 0;
             std::size_t wsize2 = wsize;
             if (wsize)
             {
                 if (wsize > rem)
                     wsize = rem;
                 std::memcpy(wptr, (const char*)_xidp + rec_offs, wsize);
                 wr_cnt += wsize;
                 rem -= wsize;
             }
             rec_offs -= _txn_hdr._xidsize - wsize2;
             checksum.addData((unsigned char*)wptr, wr_cnt);
             if (rem)
             {
                 _txn_tail._checksum = checksum.getChecksum();
                 wsize = sizeof(_txn_tail) > rec_offs ? sizeof(_txn_tail) - rec_offs : 0;
                 wsize2 = wsize;
                 if (wsize)
                 {
                     if (wsize > rem)
                         wsize = rem;
                     std::memcpy((char*)wptr + wr_cnt, (char*)&_txn_tail + rec_offs, wsize);
                     wr_cnt += wsize;
                     rem -= wsize;
                 }
                 rec_offs -= sizeof(_txn_tail) - wsize2;
             }
             assert(rem == 0);
             assert(rec_offs == 0);
         }
         else // No further split required
         {
             rec_offs -= sizeof(txn_hdr_t);
             std::size_t wsize = _txn_hdr._xidsize > rec_offs ? _txn_hdr._xidsize - rec_offs : 0;
             if (wsize)
             {
                 std::memcpy(wptr, (const char*)_xidp + rec_offs, wsize);
                 wr_cnt += wsize;
                 checksum.addData((unsigned char*)wptr, wr_cnt);
             }
             rec_offs -= _txn_hdr._xidsize - wsize;
             _txn_tail._checksum = checksum.getChecksum();
             wsize = sizeof(_txn_tail) > rec_offs ? sizeof(_txn_tail) - rec_offs : 0;
             if (wsize)
             {
                 std::memcpy((char*)wptr + wr_cnt, (char*)&_txn_tail + rec_offs, wsize);
                 wr_cnt += wsize;
 #ifdef QLS_CLEAN
                 std::size_t rec_offs = rec_offs_dblks * QLS_DBLK_SIZE_BYTES;
                 std::size_t dblk_rec_size = size_dblks(rec_size() - rec_offs) * QLS_DBLK_SIZE_BYTES;
                 std::memset((char*)wptr + wr_cnt, QLS_CLEAN_CHAR, dblk_rec_size - wr_cnt);
 #endif
             }
             rec_offs -= sizeof(_txn_tail) - wsize;
             assert(rec_offs == 0);
         }
     }
     else // Start at beginning of data record
     {
         // Assumption: the header will always fit into the first dblk
         std::memcpy(wptr, (void*)&_txn_hdr, sizeof(txn_hdr_t));
         wr_cnt = sizeof(txn_hdr_t);
         if (size_dblks(rec_size()) > max_size_dblks) // Split required
         {
             std::size_t wsize;
             rem -= sizeof(txn_hdr_t);
             if (rem)
             {
                 wsize = rem >= _txn_hdr._xidsize ? _txn_hdr._xidsize : rem;
                 std::memcpy((char*)wptr + wr_cnt, _xidp, wsize);
                 wr_cnt += wsize;
                 rem -= wsize;
             }
             checksum.addData((unsigned char*)wptr, wr_cnt);
             if (rem)
             {
                 _txn_tail._checksum = checksum.getChecksum();
                 wsize = rem >= sizeof(_txn_tail) ? sizeof(_txn_tail) : rem;
                 std::memcpy((char*)wptr + wr_cnt, (void*)&_txn_tail, wsize);
                 wr_cnt += wsize;
                 rem -= wsize;
             }
             assert(rem == 0);
         }
         else // No split required
         {
             std::memcpy((char*)wptr + wr_cnt, _xidp, _txn_hdr._xidsize);
             wr_cnt += _txn_hdr._xidsize;
             checksum.addData((unsigned char*)wptr, wr_cnt);
             _txn_tail._checksum = checksum.getChecksum();
             std::memcpy((char*)wptr + wr_cnt, (void*)&_txn_tail, sizeof(_txn_tail));
             wr_cnt += sizeof(_txn_tail);
 #ifdef QLS_CLEAN
             std::size_t dblk_rec_size = size_dblks(rec_size()) * QLS_DBLK_SIZE_BYTES;
             std::memset((char*)wptr + wr_cnt, QLS_CLEAN_CHAR, dblk_rec_size - wr_cnt);
 #endif
         }
     }
     return size_dblks(wr_cnt);
 }

 bool
 txn_rec::decode(::rec_hdr_t& h, std::ifstream* ifsp, std::size_t& rec_offs, const std::streampos rec_start)
 {
     if (rec_offs == 0)
     {
         // Read header, allocate for xid
         ::rec_hdr_copy(&_txn_hdr._rhdr, &h);
         ifsp->read((char*)&_txn_hdr._xidsize, sizeof(_txn_hdr._xidsize));
         rec_offs = sizeof(::txn_hdr_t);
         _xid_buff = std::malloc(_txn_hdr._xidsize);
         MALLOC_CHK(_xid_buff, "_buff", "txn_rec", "rcv_decode");
     }
     if (rec_offs < sizeof(txn_hdr_t) + _txn_hdr._xidsize)
     {
         // Read xid (or continue reading xid)
         std::size_t offs = rec_offs - sizeof(txn_hdr_t);
         ifsp->read((char*)_xid_buff + offs, _txn_hdr._xidsize - offs);
         std::size_t size_read = ifsp->gcount();
         rec_offs += size_read;
         if (size_read < _txn_hdr._xidsize - offs)
         {
             assert(ifsp->eof());
             // As we may have read past eof, turn off fail bit
             ifsp->clear(ifsp->rdstate()&(~std::ifstream::failbit));
             assert(!ifsp->fail() && !ifsp->bad());
             return false;
         }
     }
     if (rec_offs < sizeof(txn_hdr_t) + _txn_hdr._xidsize + sizeof(rec_tail_t))
     {
         // Read tail (or continue reading tail)
         std::size_t offs = rec_offs - sizeof(txn_hdr_t) - _txn_hdr._xidsize;
         ifsp->read((char*)&_txn_tail + offs, sizeof(rec_tail_t) - offs);
         std::size_t size_read = ifsp->gcount();
         rec_offs += size_read;
         if (size_read < sizeof(rec_tail_t) - offs)
         {
             assert(ifsp->eof());
             // As we may have read past eof, turn off fail bit
             ifsp->clear(ifsp->rdstate()&(~std::ifstream::failbit));
             assert(!ifsp->fail() && !ifsp->bad());
             return false;
         }
         check_rec_tail(rec_start);
     }
     ifsp->ignore(rec_size_dblks() * QLS_DBLK_SIZE_BYTES - rec_size());
     assert(!ifsp->fail() && !ifsp->bad());
     assert(_txn_hdr._xidsize > 0);
     return true;
 }

 std::size_t
 txn_rec::get_xid(void** const xidpp)
 {
     if (!_xid_buff)
     {
         *xidpp = 0;
         return 0;
     }
     *xidpp = _xid_buff;
     return _txn_hdr._xidsize;
 }

 std::string&
 txn_rec::str(std::string& str) const
 {
     std::ostringstream oss;
     if (_txn_hdr._rhdr._magic == QLS_TXA_MAGIC)
         oss << "dtxa_rec: m=" << _txn_hdr._rhdr._magic;
     else
         oss << "dtxc_rec: m=" << _txn_hdr._rhdr._magic;
     oss << " v=" << (int)_txn_hdr._rhdr._version;
     oss << " rid=" << _txn_hdr._rhdr._rid;
     oss << " xid=\"" << _xidp << "\"";
     str.append(oss.str());
     return str;
 }

 std::size_t
 txn_rec::xid_size() const
 {
     return _txn_hdr._xidsize;
 }

 std::size_t
 txn_rec::rec_size() const
 {
     return sizeof(txn_hdr_t) + _txn_hdr._xidsize + sizeof(rec_tail_t);
 }

 void
 txn_rec::check_rec_tail(const std::streampos rec_start) const {
     Checksum checksum;
     checksum.addData((const unsigned char*)&_txn_hdr, sizeof(::txn_hdr_t));
     if (_txn_hdr._xidsize > 0) {
         checksum.addData((const unsigned char*)_xid_buff, _txn_hdr._xidsize);
     }
     uint32_t cs = checksum.getChecksum();
     uint16_t res = ::rec_tail_check(&_txn_tail, &_txn_hdr._rhdr, cs);
     if (res != 0) {
         std::stringstream oss;
         oss << std::endl << "  Record offset: 0x" << std::hex << rec_start;
         if (res & ::REC_TAIL_MAGIC_ERR_MASK) {
             oss << std::endl << "  Magic: expected 0x" << ~_txn_hdr._rhdr._magic << "; found 0x" << _txn_tail._xmagic;
         }
         if (res & ::REC_TAIL_SERIAL_ERR_MASK) {
             oss << std::endl << "  Serial: expected 0x" << _txn_hdr._rhdr._serial << "; found 0x" << _txn_tail._serial;
         }
         if (res & ::REC_TAIL_RID_ERR_MASK) {
             oss << std::endl << "  Record Id: expected 0x" << _txn_hdr._rhdr._rid << "; found 0x" << _txn_tail._rid;
         }
         if (res & ::REC_TAIL_CHECKSUM_ERR_MASK) {
             oss << std::endl << "  Checksum: expected 0x" << cs << "; found 0x" << _txn_tail._checksum;
         }
         throw jexception(jerrno::JERR_JREC_BADRECTAIL, oss.str(), "txn_rec", "check_rec_tail");
     }
 }

 void
 txn_rec::clean()
 {
     if (_xid_buff) {
         std::free(_xid_buff);
         _xid_buff = 0;
     }
 }

 }}}
	/*
	*
	* 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.
	*
	*/

	#include "qpid/linearstore/journal/txn_rec.h"

	#include <cassert>
	#include <cstring>
	#include "qpid/linearstore/journal/Checksum.h"
	#include "qpid/linearstore/journal/jexception.h"

	namespace qpid {
	namespace linearstore {
	namespace journal {

	txn_rec::txn_rec():
	_xidp(0),
	_xid_buff(0)
	{
	::txn_hdr_init(&_txn_hdr, 0, QLS_JRNL_VERSION, 0, 0, 0, 0);
	::rec_tail_init(&_txn_tail, 0, 0, 0, 0);
	}

	txn_rec::~txn_rec()
	{
	clean();
	}

	void
	txn_rec::reset(const bool commitFlag, const uint64_t serial, const uint64_t rid, const void* const xidp,
	const std::size_t xidlen)
	{
	_txn_hdr._rhdr._magic = commitFlag ? QLS_TXC_MAGIC : QLS_TXA_MAGIC;
	_txn_hdr._rhdr._serial = serial;
	_txn_hdr._rhdr._rid = rid;
	_txn_hdr._xidsize = xidlen;
	_xidp = xidp;
	_xid_buff = 0;
	_txn_tail._xmagic = ~_txn_hdr._rhdr._magic;
	_txn_tail._serial = serial;
	_txn_tail._rid = rid;
	_txn_tail._checksum = 0UL;
	}

	uint32_t
	txn_rec::encode(void* wptr, uint32_t rec_offs_dblks, uint32_t max_size_dblks, Checksum& checksum)
	{
	assert(wptr != 0);
	assert(max_size_dblks > 0);
	assert(_xidp != 0 && _txn_hdr._xidsize > 0);

	std::size_t rec_offs = rec_offs_dblks * QLS_DBLK_SIZE_BYTES;
	std::size_t rem = max_size_dblks * QLS_DBLK_SIZE_BYTES;
	std::size_t wr_cnt = 0;
	if (rec_offs_dblks) // Continuation of split dequeue record (over 2 or more pages)
	{
	if (size_dblks(rec_size()) - rec_offs_dblks > max_size_dblks) // Further split required
	{
	rec_offs -= sizeof(txn_hdr_t);
	std::size_t wsize = _txn_hdr._xidsize > rec_offs ? _txn_hdr._xidsize - rec_offs : 0;
	std::size_t wsize2 = wsize;
	if (wsize)
	{
	if (wsize > rem)
	wsize = rem;
	std::memcpy(wptr, (const char*)_xidp + rec_offs, wsize);
	wr_cnt += wsize;
	rem -= wsize;
	}
	rec_offs -= _txn_hdr._xidsize - wsize2;
	checksum.addData((unsigned char*)wptr, wr_cnt);
	if (rem)
	{
	_txn_tail._checksum = checksum.getChecksum();
	wsize = sizeof(_txn_tail) > rec_offs ? sizeof(_txn_tail) - rec_offs : 0;
	wsize2 = wsize;
	if (wsize)
	{
	if (wsize > rem)
	wsize = rem;
	std::memcpy((char)wptr + wr_cnt, (char)&_txn_tail + rec_offs, wsize);
	wr_cnt += wsize;
	rem -= wsize;
	}
	rec_offs -= sizeof(_txn_tail) - wsize2;
	}
	assert(rem == 0);
	assert(rec_offs == 0);
	}
	else // No further split required
	{
	rec_offs -= sizeof(txn_hdr_t);
	std::size_t wsize = _txn_hdr._xidsize > rec_offs ? _txn_hdr._xidsize - rec_offs : 0;
	if (wsize)
	{
	std::memcpy(wptr, (const char*)_xidp + rec_offs, wsize);
	wr_cnt += wsize;
	checksum.addData((unsigned char*)wptr, wr_cnt);
	}
	rec_offs -= _txn_hdr._xidsize - wsize;
	_txn_tail._checksum = checksum.getChecksum();
	wsize = sizeof(_txn_tail) > rec_offs ? sizeof(_txn_tail) - rec_offs : 0;
	if (wsize)
	{
	std::memcpy((char)wptr + wr_cnt, (char)&_txn_tail + rec_offs, wsize);
	wr_cnt += wsize;
	#ifdef QLS_CLEAN
	std::size_t rec_offs = rec_offs_dblks * QLS_DBLK_SIZE_BYTES;
	std::size_t dblk_rec_size = size_dblks(rec_size() - rec_offs) * QLS_DBLK_SIZE_BYTES;
	std::memset((char*)wptr + wr_cnt, QLS_CLEAN_CHAR, dblk_rec_size - wr_cnt);
	#endif
	}
	rec_offs -= sizeof(_txn_tail) - wsize;
	assert(rec_offs == 0);
	}
	}
	else // Start at beginning of data record
	{
	// Assumption: the header will always fit into the first dblk
	std::memcpy(wptr, (void*)&_txn_hdr, sizeof(txn_hdr_t));
	wr_cnt = sizeof(txn_hdr_t);
	if (size_dblks(rec_size()) > max_size_dblks) // Split required
	{
	std::size_t wsize;
	rem -= sizeof(txn_hdr_t);
	if (rem)
	{
	wsize = rem >= _txn_hdr._xidsize ? _txn_hdr._xidsize : rem;
	std::memcpy((char*)wptr + wr_cnt, _xidp, wsize);
	wr_cnt += wsize;
	rem -= wsize;
	}
	checksum.addData((unsigned char*)wptr, wr_cnt);
	if (rem)
	{
	_txn_tail._checksum = checksum.getChecksum();
	wsize = rem >= sizeof(_txn_tail) ? sizeof(_txn_tail) : rem;
	std::memcpy((char)wptr + wr_cnt, (void)&_txn_tail, wsize);
	wr_cnt += wsize;
	rem -= wsize;
	}
	assert(rem == 0);
	}
	else // No split required
	{
	std::memcpy((char*)wptr + wr_cnt, _xidp, _txn_hdr._xidsize);
	wr_cnt += _txn_hdr._xidsize;
	checksum.addData((unsigned char*)wptr, wr_cnt);
	_txn_tail._checksum = checksum.getChecksum();
	std::memcpy((char)wptr + wr_cnt, (void)&_txn_tail, sizeof(_txn_tail));
	wr_cnt += sizeof(_txn_tail);
	#ifdef QLS_CLEAN
	std::size_t dblk_rec_size = size_dblks(rec_size()) * QLS_DBLK_SIZE_BYTES;
	std::memset((char*)wptr + wr_cnt, QLS_CLEAN_CHAR, dblk_rec_size - wr_cnt);
	#endif
	}
	}
	return size_dblks(wr_cnt);
	}

	bool
	txn_rec::decode(::rec_hdr_t& h, std::ifstream* ifsp, std::size_t& rec_offs, const std::streampos rec_start)
	{
	if (rec_offs == 0)
	{
	// Read header, allocate for xid
	::rec_hdr_copy(&_txn_hdr._rhdr, &h);
	ifsp->read((char*)&_txn_hdr._xidsize, sizeof(_txn_hdr._xidsize));
	rec_offs = sizeof(::txn_hdr_t);
	_xid_buff = std::malloc(_txn_hdr._xidsize);
	MALLOC_CHK(_xid_buff, "_buff", "txn_rec", "rcv_decode");
	}
	if (rec_offs < sizeof(txn_hdr_t) + _txn_hdr._xidsize)
	{
	// Read xid (or continue reading xid)
	std::size_t offs = rec_offs - sizeof(txn_hdr_t);
	ifsp->read((char*)_xid_buff + offs, _txn_hdr._xidsize - offs);
	std::size_t size_read = ifsp->gcount();
	rec_offs += size_read;
	if (size_read < _txn_hdr._xidsize - offs)
	{
	assert(ifsp->eof());
	// As we may have read past eof, turn off fail bit
	ifsp->clear(ifsp->rdstate()&(~std::ifstream::failbit));
	assert(!ifsp->fail() && !ifsp->bad());
	return false;
	}
	}
	if (rec_offs < sizeof(txn_hdr_t) + _txn_hdr._xidsize + sizeof(rec_tail_t))
	{
	// Read tail (or continue reading tail)
	std::size_t offs = rec_offs - sizeof(txn_hdr_t) - _txn_hdr._xidsize;
	ifsp->read((char*)&_txn_tail + offs, sizeof(rec_tail_t) - offs);
	std::size_t size_read = ifsp->gcount();
	rec_offs += size_read;
	if (size_read < sizeof(rec_tail_t) - offs)
	{
	assert(ifsp->eof());
	// As we may have read past eof, turn off fail bit
	ifsp->clear(ifsp->rdstate()&(~std::ifstream::failbit));
	assert(!ifsp->fail() && !ifsp->bad());
	return false;
	}
	check_rec_tail(rec_start);
	}
	ifsp->ignore(rec_size_dblks() * QLS_DBLK_SIZE_BYTES - rec_size());
	assert(!ifsp->fail() && !ifsp->bad());
	assert(_txn_hdr._xidsize > 0);
	return true;
	}

	std::size_t
	txn_rec::get_xid(void** const xidpp)
	{
	if (!_xid_buff)
	{
	*xidpp = 0;
	return 0;
	}
	*xidpp = _xid_buff;
	return _txn_hdr._xidsize;
	}

	std::string&
	txn_rec::str(std::string& str) const
	{
	std::ostringstream oss;
	if (_txn_hdr._rhdr._magic == QLS_TXA_MAGIC)
	oss << "dtxa_rec: m=" << _txn_hdr._rhdr._magic;
	else
	oss << "dtxc_rec: m=" << _txn_hdr._rhdr._magic;
	oss << " v=" << (int)_txn_hdr._rhdr._version;
	oss << " rid=" << _txn_hdr._rhdr._rid;
	oss << " xid=\"" << _xidp << "\"";
	str.append(oss.str());
	return str;
	}

	std::size_t
	txn_rec::xid_size() const
	{
	return _txn_hdr._xidsize;
	}

	std::size_t
	txn_rec::rec_size() const
	{
	return sizeof(txn_hdr_t) + _txn_hdr._xidsize + sizeof(rec_tail_t);
	}

	void
	txn_rec::check_rec_tail(const std::streampos rec_start) const {
	Checksum checksum;
	checksum.addData((const unsigned char*)&_txn_hdr, sizeof(::txn_hdr_t));
	if (_txn_hdr._xidsize > 0) {
	checksum.addData((const unsigned char*)_xid_buff, _txn_hdr._xidsize);
	}
	uint32_t cs = checksum.getChecksum();
	uint16_t res = ::rec_tail_check(&_txn_tail, &_txn_hdr._rhdr, cs);
	if (res != 0) {
	std::stringstream oss;
	oss << std::endl << " Record offset: 0x" << std::hex << rec_start;
	if (res & ::REC_TAIL_MAGIC_ERR_MASK) {
	oss << std::endl << " Magic: expected 0x" << ~_txn_hdr._rhdr._magic << "; found 0x" << _txn_tail._xmagic;
	}
	if (res & ::REC_TAIL_SERIAL_ERR_MASK) {
	oss << std::endl << " Serial: expected 0x" << _txn_hdr._rhdr._serial << "; found 0x" << _txn_tail._serial;
	}
	if (res & ::REC_TAIL_RID_ERR_MASK) {
	oss << std::endl << " Record Id: expected 0x" << _txn_hdr._rhdr._rid << "; found 0x" << _txn_tail._rid;
	}
	if (res & ::REC_TAIL_CHECKSUM_ERR_MASK) {
	oss << std::endl << " Checksum: expected 0x" << cs << "; found 0x" << _txn_tail._checksum;
	}
	throw jexception(jerrno::JERR_JREC_BADRECTAIL, oss.str(), "txn_rec", "check_rec_tail");
	}
	}

	void
	txn_rec::clean()
	{
	if (_xid_buff) {
	std::free(_xid_buff);
	_xid_buff = 0;
	}
	}

	}}}