duplicity.librsync module

Provides a high-level interface to some librsync functions

This is a python wrapper around the lower-level _librsync module, which is written in C. The goal was to use C as little as possible…

class duplicity.librsync.DeltaFile(signature, new_file)

Bases: LikeFile

File-like object which incrementally generates a librsync delta

__init__(signature, new_file)

DeltaFile initializer - call with signature and new file

Signature can either be a string or a file with read() and close() methods. New_file also only needs to have read() and close() methods. It will be closed when self is closed.

class duplicity.librsync.LikeFile(infile, need_seek=None)

Bases: object

File-like object used by SigFile, DeltaFile, and PatchFile

__init__(infile, need_seek=None)

LikeFile initializer - zero buffers, set eofs off

_add_to_inbuf()

Make sure len(self.inbuf) >= blocksize

_add_to_outbuf_once()

Add one cycle’s worth of output to self.outbuf

check_file(file, need_seek=None)

Raise type error if file doesn’t have necessary attributes

close()

Close infile

maker = None

mode = 'rb'

read(length=-1)

Build up self.outbuf, return first length bytes

class duplicity.librsync.PatchedFile(basis_file, delta_file)

Bases: LikeFile

File-like object which applies a librsync delta incrementally

__init__(basis_file, delta_file)

PatchedFile initializer - call with basis delta

Here basis_file must be a true Python file, because we may need to seek() around in it a lot, and this is done in C. delta_file only needs read() and close() methods.

class duplicity.librsync.SigFile(infile, blocksize=duplicity._librsync.RS_DEFAULT_BLOCK_LEN)

Bases: LikeFile

File-like object which incrementally generates a librsync signature

__init__(infile, blocksize=duplicity._librsync.RS_DEFAULT_BLOCK_LEN)

SigFile initializer - takes basis file

basis file only needs to have read() and close() methods. It will be closed when we come to the end of the signature.

class duplicity.librsync.SigGenerator(blocksize=duplicity._librsync.RS_DEFAULT_BLOCK_LEN)

Bases: object

Calculate signature.

Input and output is same as SigFile, but the interface is like md5 module, not filelike object

__init__(blocksize=duplicity._librsync.RS_DEFAULT_BLOCK_LEN)

Return new signature instance

getsig()

Return signature over given data

process_buffer()

Run self.buffer through sig_maker, add to self.sig_string

update(buf)

Add buf to data that signature will be calculated over

exception duplicity.librsync.librsyncError

Bases: Exception

Signifies error in internal librsync processing (bad signature, etc.)

underlying _librsync.librsyncError’s are regenerated using this class because the C-created exceptions are by default unPickleable. There is probably a way to fix this in _librsync, but this scheme was easier.