Cpl::Persistent::MirroredChunk Class Reference

This concrete class implements the Chunk interface by storing two copies of the Record's data. More...

Detailed Description

This concrete class implements the Chunk interface by storing two copies of the Record's data.

This ensures that if power fails during a write operation to persistent media - there will also be a good 'previous' copy of the data available.

#include <MirroredChunk.h>

Inheritance diagram for Cpl::Persistent::MirroredChunk:

Collaboration diagram for Cpl::Persistent::MirroredChunk:

Public Member Functions
	MirroredChunk (RegionMedia &regionA, RegionMedia &regionB)
	Constructor.
void	start (Cpl::Dm::MailboxServer &myMbox) noexcept
	See Cpl::Persistent::Chunk.
void	stop () noexcept
	See Cpl::Persistent::Chunk.
bool	loadData (Payload &dstHandler, size_t index=0) noexcept
	See Cpl::Persistent::Chunk.
bool	updateData (Payload &srcHandler, size_t index=0, bool invalidate=false) noexcept
	See Cpl::Persistent::Chunk.
size_t	getMetadataLength () const noexcept
	See Cpl::Persistent::Chunk.
Public Member Functions inherited from Cpl::Persistent::Chunk
virtual	~Chunk ()
	Virtual destructor.

Static Public Attributes
static constexpr size_t	FRAME_OFFSET_DATA_LEN = sizeof(uint64_t)
	Length of the data.
static constexpr size_t	FRAME_OFFSET_DATA = sizeof( size_t ) + FRAME_OFFSET_DATA_LEN
	Start of data (aka overhead length)
static constexpr size_t	CRC_SIZE = sizeof( uint32_t )
	The size of the CRC.
static constexpr size_t	FRAME_OVERHEAD = FRAME_OFFSET_DATA + CRC_SIZE
	Total overhead size.

Protected Member Functions
virtual uint64_t	getTransactionId (RegionMedia &region, size_t &dataLen, size_t index=0)
	Helper method. If the region is 'corrupt' a transaction ID of zero is returned.
virtual bool	pushToRecord (Payload &dstHandler)
	Helper method. Encapsulates pushing data to the record.
virtual size_t	pullFromRecord (Payload &srcHandler)
	Helper method. Encapsulates retrieving data from the record. Returns the length of the data.
virtual void	reset ()
	Helper method. Encapsulates actions that occur when there is NO VALID data.

Protected Attributes
RegionMedia &	m_regionA
	Region/Media for copy A.
RegionMedia &	m_regionB
	Region/Media for copy B.
uint64_t	m_transId
	Current Transaction ID (the larger the value - the newer the data)
size_t	m_dataLen
	Data Length for the region.
RegionMedia *	m_currentRegion
	Pointer to the current region (i.e. newest read/written region)

Constructor & Destructor Documentation

MirroredChunk()

Cpl::Persistent::MirroredChunk::MirroredChunk	(	RegionMedia &	regionA,
		RegionMedia &	regionB
	)

Constructor.

Member Function Documentation

getMetadataLength()

size_t Cpl::Persistent::MirroredChunk::getMetadataLength ( ) const

virtualnoexcept

See Cpl::Persistent::Chunk.

Implements Cpl::Persistent::Chunk.

getTransactionId()

virtual uint64_t Cpl::Persistent::MirroredChunk::getTransactionId ( RegionMedia &  region, size_t &  dataLen, size_t  index = 0  )

protectedvirtual

Helper method. If the region is 'corrupt' a transaction ID of zero is returned.

loadData()

bool Cpl::Persistent::MirroredChunk::loadData ( Payload &  dstHandler, size_t  index = 0  )

virtualnoexcept

See Cpl::Persistent::Chunk.

Implements Cpl::Persistent::Chunk.

pullFromRecord()

virtual size_t Cpl::Persistent::MirroredChunk::pullFromRecord ( Payload &  srcHandler )

protectedvirtual

Helper method. Encapsulates retrieving data from the record. Returns the length of the data.

pushToRecord()

virtual bool Cpl::Persistent::MirroredChunk::pushToRecord ( Payload &  dstHandler )

protectedvirtual

Helper method. Encapsulates pushing data to the record.

reset()

virtual void Cpl::Persistent::MirroredChunk::reset ( )

protectedvirtual

Helper method. Encapsulates actions that occur when there is NO VALID data.

start()

void Cpl::Persistent::MirroredChunk::start ( Cpl::Dm::MailboxServer &  myMbox )

virtualnoexcept

See Cpl::Persistent::Chunk.

Implements Cpl::Persistent::Chunk.

stop()

void Cpl::Persistent::MirroredChunk::stop ( )

virtualnoexcept

See Cpl::Persistent::Chunk.

Implements Cpl::Persistent::Chunk.

updateData()

bool Cpl::Persistent::MirroredChunk::updateData ( Payload &  srcHandler, size_t  index = 0, bool  invalidate = false  )

virtualnoexcept

See Cpl::Persistent::Chunk.

Implements Cpl::Persistent::Chunk.

Member Data Documentation

CRC_SIZE

constexpr size_t Cpl::Persistent::MirroredChunk::CRC_SIZE = sizeof( uint32_t )

staticconstexpr

The size of the CRC.

FRAME_OFFSET_DATA

constexpr size_t Cpl::Persistent::MirroredChunk::FRAME_OFFSET_DATA = sizeof( size_t ) + FRAME_OFFSET_DATA_LEN

staticconstexpr

Start of data (aka overhead length)

FRAME_OFFSET_DATA_LEN

constexpr size_t Cpl::Persistent::MirroredChunk::FRAME_OFFSET_DATA_LEN = sizeof(uint64_t)

staticconstexpr

Length of the data.

FRAME_OVERHEAD

constexpr size_t Cpl::Persistent::MirroredChunk::FRAME_OVERHEAD = FRAME_OFFSET_DATA + CRC_SIZE

staticconstexpr

Total overhead size.

m_currentRegion

RegionMedia* Cpl::Persistent::MirroredChunk::m_currentRegion

protected

Pointer to the current region (i.e. newest read/written region)

m_dataLen

size_t Cpl::Persistent::MirroredChunk::m_dataLen

protected

Data Length for the region.

m_regionA

RegionMedia& Cpl::Persistent::MirroredChunk::m_regionA

protected

Region/Media for copy A.

m_regionB

RegionMedia& Cpl::Persistent::MirroredChunk::m_regionB

protected

Region/Media for copy B.

m_transId

uint64_t Cpl::Persistent::MirroredChunk::m_transId

protected

Current Transaction ID (the larger the value - the newer the data)

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The documentation for this class was generated from the following file:

• Cpl/Persistent/MirroredChunk.h