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Diffstat (limited to 'cpp/src/qpid/asyncStore/jrnl2/EnqueueHeader.h')
| -rw-r--r-- | cpp/src/qpid/asyncStore/jrnl2/EnqueueHeader.h | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/cpp/src/qpid/asyncStore/jrnl2/EnqueueHeader.h b/cpp/src/qpid/asyncStore/jrnl2/EnqueueHeader.h new file mode 100644 index 0000000000..4d6dc9cfed --- /dev/null +++ b/cpp/src/qpid/asyncStore/jrnl2/EnqueueHeader.h @@ -0,0 +1,219 @@ +/* + * 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 EnqueueHeader.h + * + * List of journal record structs: + * struct DequeueHeader + * struct EnqueueHeader <-- This file + * 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_EnqueueHeader_h_ +#define qpid_asyncStore_jrnl2_EnqueueHeader_h_ + +#include "EventHeader.h" + +namespace qpid { +namespace asyncStore { +namespace jrnl2 { + +#pragma pack(1) + +/** + * \brief Struct for enqueue record header. This record stores message data to the + * journal. + * + * Enqueue records record the content of messages for possible later recovery, and + * are so-called because they correspond with the event of enqueuing the record on + * a queue. + * + * In addition to the fields inherited from RecordHeader, this struct includes both the + * transaction id (xid) and data blob sizes. + * + * This header precedes the enqueued message data in journal files, and unless there is + * no xid and no data (both with 0 length), is followed by a RecordTail. + * + * Record layout in binary format (32 bytes): + * <pre> + * 0x0 0x7 + * +-----+-----+-----+-----+-----+-----+-----+-----+ -+ + * 0x00 | m_magic | v | e | m_flags | | + * +-----+-----+-----+-----+-----+-----+-----+-----+ | struct RecordHeader + * 0x08 | m_recordId | | + * +-----+-----+-----+-----+-----+-----+-----+-----+ -+ + * 0x10 | m_xidSize | + * +-----+-----+-----+-----+-----+-----+-----+-----+ + * 0x18 | m_dataSize | + * +-----+-----+-----+-----+-----+-----+-----+-----+ + * </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> + * No content (ie m_xidSize==0 AND m_dataSize==0): + * +---------+ + * | enqueue | + * | header | + * +---------+ + * <-- 32 ---> + * + * With content: + * +---------+----------------+---------------------------+--------+ + * | enqueue | XID | Data | record | + * | header | | | tail | + * +---------+----------------+---------------------------+--------+ + * <-- 32 ---><-- m_xidSize --><------ m_dataSize -------><-- 16 --> + * </pre> + */ +class EnqueueHeader : public EventHeader +{ +public: + /** + * \brief Mask for the record header flags field m_flags which is used to indicate that a record is transient + * (if the flag is set) or durable (if the flag is not set). + */ + static const uint16_t ENQ_HDR_TRANSIENT_MASK = 0x10; + + /** + * \brief Mask for the record header flags field m_flags which is used to indicate that a record is using + * external storage for its data content (if the flag is set). If the flag is not set, then the data content + * is stored in the journal itself. + */ + static const uint16_t ENQ_HDR_EXTERNAL_MASK = 0x20; + + /** + * \brief Default constructor, which sets all values to 0. + */ + EnqueueHeader(); + + /** + * \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 xidSize Size of the transaction (or distributed transaction) ID for this record + * \param dataSize Size of the opaque data block for this record + * \param overwriteIndicator Flag indicating the present value of the overwrite indicator when writing this + * record + * \param transient Flag indicating that this record is transient (ie to be discarded on recovery) + * \param external Flag indicating that this record's data is stored externally to the journal, the data portion + * of the record identifies the storage location. + */ + EnqueueHeader(const uint32_t magic, + const uint8_t version, + const uint64_t recordId, + const uint64_t xidSize, + const uint64_t dataSize, + const bool overwriteIndicator, + const bool transient = false, + const bool external = false); + + /** + * \brief Copy constructor + * + * \param eh Instance to be copied + */ + EnqueueHeader(const EnqueueHeader& eh); + + /** + * \brief Virtual destructor + */ + virtual ~EnqueueHeader(); + + /** + * \brief Return the value of the Transient flag for this record. If set, this record is ignored during + * recovery. + * + * \returns true if the Transient flag for this record is set, false otherwise. + */ + bool getTransientFlag() const; + + /** + * \brief Set the value of the Transient flag for this record. + * + * \param transient The value to be set in the transient flag. + */ + void setTransientFlag(const bool transient = true); + + /** + * \brief Return the value of the External flag for this record. If set, this record data is not within the + * journal but external to it. The data part of this record contains the location of the stored data. + * + * \returns true if the Transient flag for this record is set, false otherwise. + */ + bool getExternalFlag() const; + + /** + * \brief Set the value of the External flag for this record. + * + * \param external The value to be set in the External flag. + */ + void setExternalFlag(const bool external = true); + + /** + * \brief Return the header size of this record in bytes. + * + * \returns Size of record header in bytes. + */ + static uint64_t getHeaderSize(); + +}; + +#pragma pack() + +}}} // namespace qpid::asyncStore::jrnl2 + +#endif // qpid_asyncStore_jrnl2_EnqueueHeader_h_ |