libdar::zapette Class Reference

zapette emulate a file that is remotely controlled by slave_zapette More...

#include <zapette.hpp>

Inheritance diagram for libdar::zapette:

Collaboration diagram for libdar::zapette:

Public Member Functions
	zapette (const std::shared_ptr< user_interaction > &dialog, generic_file *input, generic_file *output, bool by_the_end)
	zapette constructor More...
	zapette (const zapette &ref)=default
	zapette (zapette &&ref) noexcept=default
zapette &	operator= (const zapette &ref)=default
zapette &	operator= (zapette &&ref) noexcept=default
virtual bool	skippable (skippability direction, const infinint &amount) override
	whether the implementation is able to skip More...
virtual bool	skip (const infinint &pos) override
	skip at the absolute position More...
virtual bool	skip_to_eof () override
	skip to the end of file
virtual bool	skip_relative (S_I x) override
	skip relatively to the current position
virtual bool	truncatable (const infinint &pos) const override
	whether the implementation is able to truncate to the given position
virtual infinint	get_position () const override
	get the current read/write position
virtual void	set_info_status (const std::string &s) override
	defines the new contextual value More...
virtual bool	is_an_old_start_end_archive () const override
	returns whether the archive is a old archive (format < 8)
virtual const label &	get_data_name () const override
	obtain the data_name of the archive (label associated with the archive's data) More...
infinint	get_first_slice_header_size () const
infinint	get_non_first_slice_header_size () const
Public Member Functions inherited from libdar::generic_file
	generic_file (gf_mode m)
	main constructor
	generic_file (const generic_file &ref)
	copy constructor
	generic_file (generic_file &&ref) noexcept
	move constructor
generic_file &	operator= (const generic_file &ref)
	assignment operator
generic_file &	operator= (generic_file &&ref) noexcept
	move operator
	~generic_file () noexcept(false)
	virtual destructor, More...
void	terminate ()
	destructor-like call, except that it is allowed to throw exceptions
bool	operator== (generic_file &ref)
bool	operator!= (generic_file &ref)
gf_mode	get_mode () const
	retreive the openning mode for this object
void	read_ahead (const infinint &amount)
void	ignore_read_ahead (bool mode)
virtual U_I	read (char *a, U_I size) override
	read data from the generic_file inherited from proto_generic_file
virtual void	write (const char *a, U_I size) override
	write data to the generic_file inherited from proto_generic_file
void	write (const std::string &arg)
	write a string to the generic_file More...
S_I	read_back (char &a)
	skip back one char, read on char and skip back one char
S_I	read_forward (char &a)
	read one char
virtual void	truncate (const infinint &pos)
	truncate file at the given offset More...
virtual void	copy_to (generic_file &ref)
	copy all data from current position to the object in argument
virtual void	copy_to (generic_file &ref, const infinint &crc_size, crc *&value)
	copy all data from the current position to the object in argument and computes a CRC value of the transmitted data More...
U_32	copy_to (generic_file &ref, U_32 size)
	small copy (up to 4GB) with CRC calculation
infinint	copy_to (generic_file &ref, infinint size)
	copy the given amount to the object in argument
bool	diff (generic_file &f, const infinint &me_read_ahead, const infinint &you_read_ahead, const infinint &crc_size, crc *&value)
	compares the contents with the object in argument More...
bool	diff (generic_file &f, const infinint &me_read_ahead, const infinint &you_read_ahead, const infinint &crc_size, crc *&value, infinint &err_offset)
void	reset_crc (const infinint &width)
	reset CRC on read or writen data More...
bool	crc_status () const
	to known whether CRC calculation is activated or not
crc *	get_crc ()
	get CRC of the transfered date since last reset More...
void	sync_write ()
	write any pending data
void	flush_read ()
	be ready to read at current position, reseting all pending data for reading, cached and in compression engine for example
Public Member Functions inherited from libdar::proto_generic_file
	proto_generic_file (const proto_generic_file &ref)=default
	copy constructor
	proto_generic_file (proto_generic_file &&ref) noexcept=default
	move constructor
proto_generic_file &	operator= (const proto_generic_file &ref)=default
	assignment operator
proto_generic_file &	operator= (proto_generic_file &&ref) noexcept=default
	move operator
virtual	~proto_generic_file () noexcept(false)
	virtual destructor More...
Public Member Functions inherited from libdar::contextual
	contextual (const contextual &ref)=default
	contextual (contextual &&ref) noexcept=default
contextual &	operator= (const contextual &ref)=default
contextual &	operator= (contextual &&ref) noexcept=default
virtual std::string	get_info_status () const
	get the current contextual value

Protected Member Functions
virtual void	inherited_read_ahead (const infinint &amount) override
	tells the object that several calls to read() will follow to probably obtain at least the given amount of data More...
virtual U_I	inherited_read (char *a, U_I size) override
	implementation of read() operation More...
virtual void	inherited_write (const char *a, U_I size) override
	implementation of the write() operation More...
virtual void	inherited_truncate (const infinint &pos) override
	truncate file at the give offset More...
virtual void	inherited_sync_write () override
	write down any pending data More...
virtual void	inherited_flush_read () override
	reset internal engine, flush caches in order to read the data at current position More...
virtual void	inherited_terminate () override
	destructor-like call, except that it is allowed to throw exceptions More...
Protected Member Functions inherited from libdar::generic_file
void	set_mode (gf_mode x)
bool	is_terminated () const
Protected Member Functions inherited from libdar::mem_ui
user_interaction &	get_ui () const
	get access to the user_interaction object More...
std::shared_ptr< user_interaction >	get_pointer () const
	get access to the shared_ptr pointing to the user_interaction
	mem_ui (const std::shared_ptr< user_interaction > &dialog)
	constructor More...
	mem_ui (const mem_ui &ref)=default
	the copy constructor More...
	mem_ui (mem_ui &&ref) noexcept=default
	the move constructor
mem_ui &	operator= (const mem_ui &ref)=default
	assignement operator More...
mem_ui &	operator= (mem_ui &&ref) noexcept=default
	move operator
virtual	~mem_ui () noexcept(false)
	destructor More...

Private Member Functions
void	make_transfert (U_16 size, const infinint &offset, char *data, const std::string &info, S_I &lu, infinint &arg) const
	wrapped formatted method to communicate with the slave_zapette located behind the pair of pipes (= tuyau) More...

Private Attributes
generic_file *	in
generic_file *	out
infinint	position
infinint	file_size
char	serial_counter

Additional Inherited Members
Public Types inherited from libdar::generic_file
enum	skippability { skip_backward , skip_forward }

Detailed Description

zapette emulate a file that is remotely controlled by slave_zapette

class zapette sends order to slave_zapette through a a first pipe and receive informations or data in return from a second pipe from slave_zapette

Definition at line 56 of file zapette.hpp.

Constructor & Destructor Documentation

zapette()

libdar::zapette::zapette	(	const std::shared_ptr< user_interaction > &	dialog,
		generic_file *	input,
		generic_file *	output,
		bool	by_the_end
	)

zapette constructor

Parameters

[in]	dialog	is used to return status information to the user
[in]	input	is the pipe (see class tuyau) from which is received the information or data
[in]	output	is used to send orders to slave_zapette
[in]	by_the_end	if true dar will try to open the archive starting from the end else it will try starting from the first bytes

Member Function Documentation

get_data_name()

virtual const label& libdar::zapette::get_data_name ( ) const

overridevirtual

obtain the data_name of the archive (label associated with the archive's data)

Note

label are conserved with dar_xform and archive isolation, but are not with archive merging or archive creation (full or differential backup)

Implements libdar::contextual.

get_first_slice_header_size()

infinint libdar::zapette::get_first_slice_header_size

(

)

const

get the first slice header

Note

may return 0 if the slice header is not known

get_non_first_slice_header_size()

infinint libdar::zapette::get_non_first_slice_header_size

(

)

const

get the non first slice header

Note

may return 0 if the slice header is not known

inherited_flush_read()

virtual void libdar::zapette::inherited_flush_read ( )

inlineoverrideprotectedvirtual

reset internal engine, flush caches in order to read the data at current position

Note

when the object relies on external object or system object to fetch the data from for reading, when a call to (inherited_)flush_read() occurs, the current object must not assume that any previously read data is still valid if it has internal buffers or the like and it should flush them asap. This call must not propagate the flush_read to any other gneric_file object it could rely on

Implements libdar::generic_file.

Definition at line 102 of file zapette.hpp.

inherited_read()

virtual U_I libdar::zapette::inherited_read ( char *  a, U_I  size  )

overrideprotectedvirtual

implementation of read() operation

Parameters

[in,out]	a	where to put the data to read
[in]	size	says how much data to read

Returns

the exact amount of data read and put into 'a'

Note

read as much byte as requested, up to end of file stays blocked if not enough data is available and EOF not yet met. May return less data than requested only if EOF as been reached. in other worlds, EOF is reached when returned data is stricly less than the requested data Any problem shall be reported by throwing an exception.

Implements libdar::generic_file.

inherited_read_ahead()

virtual void libdar::zapette::inherited_read_ahead ( const infinint &  amount )

inlineoverrideprotectedvirtual

tells the object that several calls to read() will follow to probably obtain at least the given amount of data

Parameters

[in]

amount

is the maximum expected amount of data that is known to be read

Note

this call may be implemented as a do-nothing call, its presence is only to allow optimization when possible, like in multi-threaded environment

Implements libdar::generic_file.

Definition at line 97 of file zapette.hpp.

inherited_sync_write()

virtual void libdar::zapette::inherited_sync_write ( )

inlineoverrideprotectedvirtual

write down any pending data

Note

called after sanity checks from generic_file::sync_write() this method's role is to write down any data pending for writing in the current object it has not to be propagated to other gneric_file object this object could rely on

Implements libdar::generic_file.

Definition at line 101 of file zapette.hpp.

inherited_terminate()

virtual void libdar::zapette::inherited_terminate ( )

overrideprotectedvirtual

destructor-like call, except that it is allowed to throw exceptions

Note

this method must never be called directly but using terminate() instead, generic_file class manages it to never be called more than once

Implements libdar::generic_file.

inherited_truncate()

virtual void libdar::zapette::inherited_truncate ( const infinint &  pos )

inlineoverrideprotectedvirtual

truncate file at the give offset

Note

if pos is greater than the current file size, this call may do nothing (not even enlarging the file)

this call should always fail on a read-only generic_file

implementation must throw exception if truncate is not possible for other reason than read/write access mode

Implements libdar::generic_file.

Definition at line 100 of file zapette.hpp.

inherited_write()

virtual void libdar::zapette::inherited_write ( const char *  a, U_I  size  )

overrideprotectedvirtual

implementation of the write() operation

Parameters

[in]	a	what data to write
[in]	size	amount of data to write

Note

must either write all data or report an error by throwing an exception

Implements libdar::generic_file.

make_transfert()

void libdar::zapette::make_transfert ( U_16  size, const infinint &  offset, char *  data, const std::string &  info, S_I &  lu, infinint &  arg  ) const

private

wrapped formatted method to communicate with the slave_zapette located behind the pair of pipes (= tuyau)

Parameters

[in]	size	is the size of the amount of data we want the zapette to send us
[in]	offset	is the byte offset of the portion of the data we want
[in,out]	data	is the location where to return the requested data
[in]	info	the new contextual string to set to the slave_zapette.
[out]	lu	the amount of byte wrote to '*data'
[out]	arg	infinint value return for special order (see note below).

Note

with default parameters, this method permits the caller to get a portion of data from the remote slave_zapette. In addition, it let the caller change the 'contextual' status of the remote object. if size is set to REQUEST_SPECIAL_ORDER, the offset is used to transmit a special order to the remote slave_zapette. Defined order are for example REQUEST_OFFSET_END_TRANSMIT , REQUEST_OFFSET_GET_FILESIZE, and so on (see at the beginning of zapette.cpp file for more). Each of these order may expect a returned value which may be an integer (provided by the "arg" argument of this call) a boolean value (provided by the "arg" argument where 0 means false and 1 means true) or a char * (first byte to put the answer to is given by 'data' and allocated space for the reply must be given through 'lu' which at return gives the effective length of the returned string

set_info_status()

virtual void libdar::zapette::set_info_status ( const std::string &  s )

overridevirtual

defines the new contextual value

Note

inherited class may redefine this call but but must call the parent method to set the value contextual:set_info_status()

Reimplemented from libdar::contextual.

skip()

virtual bool libdar::zapette::skip ( const infinint &  pos )

overridevirtual

skip at the absolute position

Parameters

[in]

pos

the offset in byte where next read/write operation must start

Returns

true if operation was successfull and false if the requested position is not valid (after end of file)

Note

if requested position is not valid the reading/writing cursor must be set to the closest valid position

Implements libdar::generic_file.

skippable()

virtual bool libdar::zapette::skippable ( skippability  direction, const infinint &  amount  )

inlineoverridevirtual

whether the implementation is able to skip

Note

the capability to skip does not mean that skip_relative() or skip() will succeed, but rather that the inherited class implementation does not by construction forbid the requested skip (like inherited class providing a generic_file interface of an anonymous pipe for example)

Implements libdar::generic_file.

Definition at line 74 of file zapette.hpp.

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

• zapette.hpp