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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 DequeueHeader.h
*
* List of journal record structs:
* struct DequeueHeader <-- This file
* struct EnqueueHeader
* struct EventHeader
* struct FileHeader
* struct RecordHeader
* struct RecordTail
* struct TransactionHeader
*
* Overview of journal record structs:
*
* <pre>
* +------------+ +--------------+
* | RecordTail | | RecordHeader |
* +------------+ | (abstract) |
* +--------------+
* ^
* |
* +----------------+---------+-------+-------------------+
* | | | |
* +------------+ +-------------+ +---------------+ +-------------------+
* | FileHeader | | EventHeader | | DequeueHeader | | TransactionHeader |
* +------------+ +-------------+ +---------------+ +-------------------+
* ^
* |
* +---------------+
* | EnqueueHeader |
* +---------------+
* </pre>
*/
#ifndef qpid_asyncStore_jrnl2_DequeueHeader_h_
#define qpid_asyncStore_jrnl2_DequeueHeader_h_
#include "qpid/asyncStore/jrnl2/RecordHeader.h"
namespace qpid {
namespace asyncStore {
namespace jrnl2 {
#pragma pack(1)
/**
* \brief Struct for dequeue record header. This record marks a previous enqueue as
* logically deleted.
*
* The dequeue record conceptually marks a previous enqueue record as dequeued,
* or logically deleted. This is achieved by recording the record ID (rid) of
* the enqueue record being deleted in the m_dequeueRecordId field. Note that this
* rid is distinct from the rid assigned to the dequeue record itself in m_recordId.
*
* Dequeue records do not carry data. However, if it is transactional (and thus has
* a transaction ID (xid), then this record will be terminated by a RecordTail struct.
* If, on the other hand, this record is non-transactional, then the rec_tail
* is absent.
*
* Note that this record had its own rid distinct from the rid of the record it is dequeuing.
* The rid field below is the rid of the dequeue record itself; the deq-rid field is the rid of a
* previous enqueue record being dequeued by this record.
*
* Record layout in binary format (32 bytes):
* <pre>
* 0x0 0x7
* +-----+-----+-----+-----+-----+-----+-----+-----+ -+
* 0x00 | m_magic | v | e | m_flags | |
* +-----+-----+-----+-----+-----+-----+-----+-----+ | struct RecordHeader
* 0x08 | m_recordId | |
* +-----+-----+-----+-----+-----+-----+-----+-----+ -+
* 0x10 | m_dequeuedRecordId |
* +-----+-----+-----+-----+-----+-----+-----+-----+
* 0x18 | m_xidSize |
* +-----+-----+-----+-----+-----+-----+-----+-----+
* </pre>
* <table>
* <tr>
* <td>v</td>
* <td>file version [ <code>_version</code> ] (If the format or encoding of
* this file changes, then this number should be incremented)</td>
* </tr>
* <tr>
* <td>e</td>
* <td>endian flag [ <code>_bigEndianFlag</code> ], <b>false</b> (0x00) for
* little endian, <b>true</b> (0x01) for big endian</td>
* </tr>
* </table>
* <pre>
* Non-transactional:
* +---------+
* | dequeue |
* | header |
* +---------+
* <-- 32 --->
*
* Transactional:
* +---------+------------------------+--------+
* | dequeue | XID | record |
* | header | | tail |
* +---------+------------------------+--------+
* <-- 32 ---><----- m_xidSize ------><-- 16 -->
* </pre>
*/
class DequeueHeader : public RecordHeader
{
public:
uint64_t m_dequeuedRecordId; ///< Record ID of dequeued record
uint64_t m_xidSize; ///< XID size
/**
* \brief Mask for the record header flags field m_flags which is used in dequeue records in the Transaction
* Prepared List (TPL) to indicate that a closed transaction resulted in a commit (if the flag is set)
* or an abort (if the flag is not set).
*/
static const uint16_t DEQ_HDR_TPL_COMMIT_ON_TXN_COMPL_MASK = 0x10;
/**
* \brief Default constructor, which sets all values to 0.
*/
DequeueHeader();
/**
* \brief Convenience constructor which initializes values during construction.
*
* \param magic The magic for this record
* \param version Version of this record
* \param recordId Record identifier for this record
* \param dequeuedRecordId Record identifier of the record being dequeued by this record
* \param xidSize Size of the transaction (or distributed transaction) ID for this record
* \param overwriteIndicator Flag indicating the present value of the overwrite indicator when writing this
* record
* \param tplCommitOnTxnComplFlag
*/
DequeueHeader(const uint32_t magic,
const uint8_t version,
const uint64_t recordId,
const uint64_t dequeuedRecordId,
const uint64_t xidSize,
const bool overwriteIndicator,
const bool tplCommitOnTxnComplFlag = false);
/**
* \brief Copy constructor
*
* \param dh Instance to be copied
*/
DequeueHeader(const DequeueHeader& dh);
/**
* \brief Virtual destructor
*/
virtual ~DequeueHeader();
/**
* \brief Convenience copy method.
*/
void copy(const DequeueHeader& dh);
/**
* \brief Reset this record to default values (mostly 0)
*/
void reset();
/**
* \brief Return the value of the tplCommitOnTxnComplFlag for this record. This flag is used only within the
* TPL, and if set, indicates that the transaction was closed using a commit. If not set, the transaction was
* closed using an abort. This is used during recovery of the transactions in the store.
*
* \returns \b true if the tplCommitOnTxnComplFlag flag for this record is set, \b false otherwise.
*/
bool getTplCommitOnTxnComplFlag() const;
/**
* \brief Set the value of the tplCommitOnTxnComplFlag for this record. This is only used in the TPL, and is
* ignored elsewhere.
*
* \param commitOnTxnCompl The value to be set in the tplCommitOnTxnComplFlag. If \b true, the transaction was
* closed with a commit; if \b false, with an abort.
*/
void setTplCommitOnTxnComplFlag(const bool commitOnTxnCompl);
/**
* \brief Return the header size of this record in bytes.
*
* \returns Size of record header in bytes.
*/
static uint64_t getHeaderSize();
/**
* \brief Return the body (xid and data) size of this record in bytes.
*
* \returns Size of record body in bytes.
*/
uint64_t getBodySize() const;
/**
* \brief Return total size of this record in bytes, being in the case of the dequeue record the size of the
* header, the size of the body (xid only) and the size of the tail.
*
* \returns Total size of record in bytes.
*/
uint64_t getRecordSize() const;
};
#pragma pack()
}}} // namespace qpid::asyncStore::jrnl2
#endif // qpid_asyncStore_jrnl2_DequeueHeader_h_
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