Binlog_cache_storage Class Reference

Byte container that provides a storage for serializing session binlog events. More...

#include <binlog_ostream.h>

Inheritance diagram for Binlog_cache_storage:

Public Member Functions
	~Binlog_cache_storage () override
bool	open (my_off_t cache_size, my_off_t max_cache_size)
void	close ()
bool	write (const unsigned char *buffer, my_off_t length) override
	Write some bytes into the output stream. More...
bool	truncate (my_off_t offset)
	Truncates some data at the end of the binlog cache. More...
bool	reset ()
	Reset status and drop all data. More...
size_t	disk_writes () const
	Returns the count of disk writes. More...
const char *	tmp_file_name () const
	Returns the name of the temporary file. More...
bool	copy_to (Basic_ostream *ostream, bool *ostream_error=nullptr)
	Copy all data to a output stream. More...
my_off_t	length () const
	Returns data length. More...
bool	is_empty () const
	Returns true if binlog cache is empty. More...
Public Member Functions inherited from Basic_ostream
virtual	~Basic_ostream ()=default

Private Attributes
Truncatable_ostream *	m_pipeline_head = nullptr
IO_CACHE_binlog_cache_storage	m_file

Detailed Description

Byte container that provides a storage for serializing session binlog events.

This way of arranging the classes separates storage layer and binlog layer, hides the implementation detail of low level storage.

Constructor & Destructor Documentation

~Binlog_cache_storage()

Binlog_cache_storage::~Binlog_cache_storage ( )

override

Member Function Documentation

close()

void Binlog_cache_storage::close

(

)

copy_to()

bool Binlog_cache_storage::copy_to ( Basic_ostream *  ostream, bool *  ostream_error = nullptr  )

inline

Copy all data to a output stream.

This function hides the internal implementation of storage detail. So it will not disturb the callers if the implementation of Binlog_cache_storage is changed. If we add a pipeline stream in this class, then we need to change the implementation of this function. But callers are not affected.

Parameters

[out]	ostream	Where the data will be copied into
[out]	ostream_error	It will be set to true if an error happens on ostream and the pointer is not null. It is valid only when the function returns true.

Return values

false	Success
true	Error happens in either the istream or ostream.

disk_writes()

size_t Binlog_cache_storage::disk_writes ( ) const

inline

Returns the count of disk writes.

is_empty()

bool Binlog_cache_storage::is_empty ( ) const

inline

Returns true if binlog cache is empty.

length()

my_off_t Binlog_cache_storage::length ( ) const

inline

Returns data length.

open()

bool Binlog_cache_storage::open	(	my_off_t	cache_size,
		my_off_t	max_cache_size
	)

reset()

bool Binlog_cache_storage::reset ( )

inline

Reset status and drop all data.

It looks like a cache was never used after reset.

tmp_file_name()

const char * Binlog_cache_storage::tmp_file_name ( ) const

inline

Returns the name of the temporary file.

truncate()

bool Binlog_cache_storage::truncate ( my_off_t  offset )

inline

Truncates some data at the end of the binlog cache.

Parameters

[in]

offset

Where the binlog cache will be truncated to.

Return values

false	Success
true	Error

write()

bool Binlog_cache_storage::write ( const unsigned char *  buffer, my_off_t  length  )

inlineoverridevirtual

Write some bytes into the output stream.

When all data is written into the stream successfully, then it return false. Otherwise, true is returned. It will never returns false when partial data is written into the stream.

Parameters

[in]	buffer	Data to be written
[in]	length	Length of the data

Return values

false	Success.
true	Error.

Implements Basic_ostream.

Member Data Documentation

m_file

IO_CACHE_binlog_cache_storage Binlog_cache_storage::m_file

private

m_pipeline_head

Truncatable_ostream* Binlog_cache_storage::m_pipeline_head = nullptr

private

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

• sql/binlog_ostream.h
• sql/binlog_ostream.cc