Binlog_encryption_istream Class Reference

Seekable_istream with decryption feature. More...

#include <binlog_istream.h>

Inheritance diagram for Binlog_encryption_istream:

Public Member Functions
	~Binlog_encryption_istream () override
bool	open (std::unique_ptr< Basic_seekable_istream > down_istream, Binlog_read_error *binlog_read_error)
	Initialize the context used in the decryption stream. More...
void	close ()
	Closes the stream. More...
ssize_t	read (unsigned char *buffer, size_t length) override
	Read some bytes from the input stream. More...
bool	seek (my_off_t offset) override
	Puts the read position to a given offset. More...
my_off_t	length () override
	The total length of the stream. More...
Public Member Functions inherited from Basic_seekable_istream
	~Basic_seekable_istream () override=default
Public Member Functions inherited from Basic_istream
virtual	~Basic_istream ()=default

Private Attributes
std::unique_ptr< Stream_cipher >	m_decryptor
std::unique_ptr< Basic_seekable_istream >	m_down_istream

Detailed Description

Seekable_istream with decryption feature.

It can be setup into an stream pipeline. In the pipeline, it decrypts the data from down stream and then feeds the decrypted data into up stream.

Constructor & Destructor Documentation

~Binlog_encryption_istream()

Binlog_encryption_istream::~Binlog_encryption_istream ( )

override

Member Function Documentation

close()

void Binlog_encryption_istream::close

(

)

Closes the stream.

It also closes the down stream and the decryptor.

length()

my_off_t Binlog_encryption_istream::length ( )

overridevirtual

The total length of the stream.

Implements Basic_seekable_istream.

open()

bool Binlog_encryption_istream::open	(	std::unique_ptr< Basic_seekable_istream >	down_istream,
		Binlog_read_error *	binlog_read_error
	)

Initialize the context used in the decryption stream.

Parameters

[in]	down_istream	The down stream where the encrypted data is stored.
[in]	binlog_read_error	Binlog_encryption_istream doesn't own a Binlog_read_error. So the caller should provide one to it. When error happens, the error type will be set into 'binlog_read_error'.

Return values

false	Succeed.
true	Error.

read()

ssize_t Binlog_encryption_istream::read ( unsigned char *  buffer, size_t  length  )

overridevirtual

Read some bytes from the input stream.

It should read exact 'length' bytes unless error happens or it reaches the end of the stream. It should block when reaching the end of a pipe that is not closed.

Parameters

[out]	buffer	Where data will be put in.
[in]	length	The number of bytes that you want to read. length should not be larger than max long.

Returns

Return values fall into three cases:

Return values

'length'	Read 'length' bytes successfully
>=0	Reach EOF, return the number of bytes actually read. It is between 0 and length-1.
-1	Error.

Implements Basic_istream.

seek()

bool Binlog_encryption_istream::seek ( my_off_t  offset )

overridevirtual

Puts the read position to a given offset.

The offset counts from the beginning of the stream. In case an implementing class transforms the data in a way that does not preserve positions, the offset here will be relative to the bytes that are read out from the stream, not relative to the bytes in lower layer storage.

it is allowed for a subclass to return success even if the position is greater than the size of the file. Error may be returned by the next read for this case. Users should call length() if they need to check that the position is within bounds.

Parameters

[in]

offset

Where the read position will be.

Return values

false	Success
true	Error

Implements Basic_seekable_istream.

Member Data Documentation

m_decryptor

std::unique_ptr<Stream_cipher> Binlog_encryption_istream::m_decryptor

private

m_down_istream

std::unique_ptr<Basic_seekable_istream> Binlog_encryption_istream::m_down_istream

private

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

• sql/binlog_istream.h
• sql/binlog_istream.cc