Abstraction for reading a stream of blocks from a commit log file. More...

#include <CommitLogBlockStream.h>

Collaboration diagram for Hypertable::CommitLogBlockStream:

Public Member Functions
	CommitLogBlockStream (FilesystemPtr &fs)

	CommitLogBlockStream (FilesystemPtr &fs, const std::string &log_dir, const std::string &fragment)

virtual	~CommitLogBlockStream ()

void	load (const std::string &log_dir, const std::string &fragment)

void	close ()

bool	next (CommitLogBlockInfo , BlockHeaderCommitLog )

std::string &	get_fname ()

Static Public Member Functions
static bool	read_header (FilesystemPtr &fs, int32_t fd, uint32_t versionp, uint64_t next_offset)
	Reads commit log file header. More...

static void	write_header (FilesystemPtr &fs, int32_t fd)
	Writes commit log file header. More...

static uint64_t	header_size ()
	Size of header. More...

Static Public Attributes
static bool	ms_assert_on_error = true

Private Member Functions
int	load_next_valid_header (BlockHeaderCommitLog *header)

bool	archive_bad_fragment (const std::string &fname, std::string &archive_fname)

Private Attributes
FilesystemPtr	m_fs
	Pointer to filesystem. More...

std::string	m_log_dir
	Directory containing commit log fragment file. More...

std::string	m_fragment
	Fragment file name within commit log directory. More...

std::string	m_fname
	Full pathname of commit log fragment file. More...

uint32_t	m_version
	Version of commit log fragment file format. More...

int32_t	m_fd
	File descriptor. More...

uint64_t	m_cur_offset
	Current read offset within the fragment file. More...

uint64_t	m_file_length
	Length of commit log fragment file. More...

DynamicBuffer	m_block_buffer
	Buffer holding most recently loaded block. More...

Detailed Description

Abstraction for reading a stream of blocks from a commit log file.

Definition at line 62 of file CommitLogBlockStream.h.

Constructor & Destructor Documentation

CommitLogBlockStream::CommitLogBlockStream ( FilesystemPtr & fs )

Definition at line 56 of file CommitLogBlockStream.cc.

CommitLogBlockStream::CommitLogBlockStream	(	FilesystemPtr &	fs,
		const std::string &	log_dir,
		const std::string &	fragment
	)

Definition at line 61 of file CommitLogBlockStream.cc.

CommitLogBlockStream::~CommitLogBlockStream ( )

virtual

Definition at line 68 of file CommitLogBlockStream.cc.

Member Function Documentation

bool CommitLogBlockStream::archive_bad_fragment	(	const std::string &	fname,
		std::string &	archive_fname
	)

private

Definition at line 270 of file CommitLogBlockStream.cc.

void CommitLogBlockStream::close ( )

Definition at line 99 of file CommitLogBlockStream.cc.

std::string& Hypertable::CommitLogBlockStream::get_fname ( )

inline

Definition at line 75 of file CommitLogBlockStream.h.

uint64_t CommitLogBlockStream::header_size ( )

static

Size of header.

Returns: Size of header in bytes

Definition at line 217 of file CommitLogBlockStream.cc.

void CommitLogBlockStream::load	(	const std::string &	log_dir,
		const std::string &	fragment
	)

Definition at line 73 of file CommitLogBlockStream.cc.

int CommitLogBlockStream::load_next_valid_header ( BlockHeaderCommitLog * header )

private

Definition at line 223 of file CommitLogBlockStream.cc.

bool CommitLogBlockStream::next	(	CommitLogBlockInfo *	infop,
		BlockHeaderCommitLog *	header
	)

Definition at line 114 of file CommitLogBlockStream.cc.

bool CommitLogBlockStream::read_header	(	FilesystemPtr &	fs,
		int32_t	fd,
		uint32_t *	versionp,
		uint64_t *	next_offset
	)

static

Reads commit log file header.

This function assumes that fd is a valid file descriptor for a commit log file that is opened for reading and positioned at the beginning of the file. It reads the header and extracts the version number, saving it to *versionp, and sets *next_offset to the file offset immediately following the header. If the header is invalid, it implies that the file is in the original format that did not have the header. In this case, *versionp is set to zero, *next_offset is set to zero, and false is returned.

Parameters

fs	Reference to filesystem object
fd	File descriptor of newly opened commit log file
versionp	Address of variable to hold version read from header
next_offset	Address of file offset variable positioned to first byte after the header

Returns: true if valid header was encountered, false otherwise

Definition at line 183 of file CommitLogBlockStream.cc.

void CommitLogBlockStream::write_header	(	FilesystemPtr &	fs,
		int32_t	fd
	)

static

Writes commit log file header.

This function assumes that fd is a valid file descriptor for a commit log file that is opened for writing and positioned at the beginning of the file. The header that is written consists of eight bytes and has the following format:

vNNNN\f\n\0

The NNNN component consists of four ASCII digits that represent the latest version number. The formfeed+newline allows the verison number to be displayed by running the Unix more on the file, which will display the version number and then pause the output.

Parameters

fs	Reference to filesystem object
fd	File descriptor of newly opened commit log file

Definition at line 209 of file CommitLogBlockStream.cc.

Member Data Documentation

DynamicBuffer Hypertable::CommitLogBlockStream::m_block_buffer

private

Buffer holding most recently loaded block.

Definition at line 155 of file CommitLogBlockStream.h.

uint64_t Hypertable::CommitLogBlockStream::m_cur_offset

private

Current read offset within the fragment file.

Definition at line 149 of file CommitLogBlockStream.h.

int32_t Hypertable::CommitLogBlockStream::m_fd

private

File descriptor.

Definition at line 146 of file CommitLogBlockStream.h.

uint64_t Hypertable::CommitLogBlockStream::m_file_length

private

Length of commit log fragment file.

Definition at line 152 of file CommitLogBlockStream.h.

std::string Hypertable::CommitLogBlockStream::m_fname

private

Full pathname of commit log fragment file.

Definition at line 140 of file CommitLogBlockStream.h.

std::string Hypertable::CommitLogBlockStream::m_fragment

private

Fragment file name within commit log directory.

Definition at line 137 of file CommitLogBlockStream.h.

FilesystemPtr Hypertable::CommitLogBlockStream::m_fs

private

Pointer to filesystem.

Definition at line 131 of file CommitLogBlockStream.h.

std::string Hypertable::CommitLogBlockStream::m_log_dir

private

Directory containing commit log fragment file.

Definition at line 134 of file CommitLogBlockStream.h.

uint32_t Hypertable::CommitLogBlockStream::m_version

private

Version of commit log fragment file format.

Definition at line 143 of file CommitLogBlockStream.h.

bool CommitLogBlockStream::ms_assert_on_error = true

static

Definition at line 77 of file CommitLogBlockStream.h.

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

/home/doug/src/hypertable/src/cc/Hypertable/Lib/CommitLogBlockStream.h
/home/doug/src/hypertable/src/cc/Hypertable/Lib/CommitLogBlockStream.cc

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation