SyncFileIO Class Reference

Helper class for doing synchronous file IO. More...

#include <os0file.h>

Public Member Functions
	SyncFileIO (os_file_t fh, void *buf, ulint n, os_offset_t offset)
	Constructor. More...
	~SyncFileIO ()=default
	Destructor. More...
ssize_t	execute (const IORequest &request)
	Do the read/write. More...
dberr_t	execute_with_retry (const IORequest &request, const size_t max_retries=NUM_RETRIES_ON_PARTIAL_IO)
	Do the read/write with retry. More...
void	advance (ssize_t n_bytes)
	Move the read/write offset up to where the partial IO succeeded. More...

Private Attributes
os_file_t	m_fh
	Open file handle. More...
void *	m_buf
	Buffer to read/write. More...
ssize_t	m_n
	Number of bytes to read/write. More...
os_offset_t	m_offset
	Offset from where to read/write. More...
const size_t	m_orig_bytes
	The total number of bytes to be read/written. More...

Detailed Description

Helper class for doing synchronous file IO.

Currently, the objective is to hide the OS specific code, so that the higher level functions aren't peppered with "#ifdef". Makes the code flow difficult to follow.

Constructor & Destructor Documentation

SyncFileIO()

SyncFileIO::SyncFileIO ( os_file_t  fh, void *  buf, ulint  n, os_offset_t  offset  )

inline

Constructor.

Parameters

[in]	fh	File handle
[in,out]	buf	Buffer to read/write
[in]	n	Number of bytes to read/write
[in]	offset	Offset where to read or write

~SyncFileIO()

SyncFileIO::~SyncFileIO ( )

default

Destructor.

Member Function Documentation

advance()

void SyncFileIO::advance ( ssize_t  n_bytes )

inline

Move the read/write offset up to where the partial IO succeeded.

Parameters

[in]

n_bytes

The number of bytes to advance

execute()

ssize_t SyncFileIO::execute

(

const IORequest &

request

)

Do the read/write.

Parameters

[in]

request

The IO context and type

Returns

the number of bytes read/written or negative value on error

execute_with_retry()

dberr_t SyncFileIO::execute_with_retry	(	const IORequest &	request,
		const size_t	max_retries = NUM_RETRIES_ON_PARTIAL_IO
	)

Do the read/write with retry.

Parameters

[in]	request	The IO context and type
[in]	max_retries	the maximum number of retries on partial i/o.

Returns

DB_SUCCESS on success, an error code on failure.

Member Data Documentation

m_buf

void* SyncFileIO::m_buf

private

Buffer to read/write.

m_fh

os_file_t SyncFileIO::m_fh

private

Open file handle.

m_n

ssize_t SyncFileIO::m_n

private

Number of bytes to read/write.

m_offset

os_offset_t SyncFileIO::m_offset

private

Offset from where to read/write.

m_orig_bytes

const size_t SyncFileIO::m_orig_bytes

private

The total number of bytes to be read/written.

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

• storage/innobase/include/os0file.h
• storage/innobase/os/os0file.cc