Package duplicity :: Module diffdir

Module diffdir

Functions for producing signatures and deltas of directories

Note that the main processes of this module have two parts. In the first, the signature or delta is constructed of a ROPath iterator. In the second, the ROPath iterator is put into tar block form.

Classes

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DeltaTarBlockIter
TarBlockIter that yields parts of a deltatar file

DiffDirException

DummyBlockIter
TarBlockIter that does no file reading

FileWithReadCounter
File-like object which also computes amount read as it is read

FileWithSignature
File-like object which also computes signature as it is read

SigTarBlockIter
TarBlockIter that yields blocks of a signature tar from path_iter

TarBlock
Contain information to add next file to tar

TarBlockIter
A bit like an iterator, yield tar blocks given input iterator

Functions

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DirDelta(path_iter, dirsig_fileobj_list)
Produce tarblock diff given dirsig_fileobj_list and pathiter

source code

DirDelta_WriteSig(path_iter, sig_infp_list, newsig_outfp)
Like DirDelta but also write signature into sig_fileobj

source code

DirFull(path_iter)
Return a tarblock full backup of items in path_iter

source code

DirFull_WriteSig(path_iter, sig_outfp)
Return full backup like above, but also write signature to sig_outfp

source code

DirSig(path_iter)
Alias for SigTarBlockIter below

source code

collate2iters(riter1, riter2)
Collate two iterators.

source code

combine_path_iters(path_iter_list)
Produce new iterator by combining the iterators in path_iter_list

source code

delta_iter_error_handler(exc, new_path, sig_path, sig_tar=None)
Called by get_delta_iter, report error in getting delta

source code

get_block_size(file_len)
Return a reasonable block size to use on files of length file_len

source code

get_combined_path_iter(sig_infp_list)
Return path iter combining signatures in list of open sig files

source code

get_delta_iter(new_iter, sig_iter, sig_fileobj=None)
Generate delta iter from new Path iter and sig Path iter.

source code

get_delta_path(new_path, sig_path, sigTarFile=None)
Return new delta_path which, when read, writes sig to sig_fileobj, if sigTarFile is not None

source code

log_delta_path(delta_path, new_path=None, stats=None)
Look at delta path and log delta.

source code

sigtar2path_iter(sigtarobj)
Convert signature tar file object open for reading into path iter

source code

write_block_iter(block_iter, out_obj)
Write block_iter to filename, path, or file object

source code

Variables

[hide private]

__package__ = 'duplicity'

stats = None
hash(x)

Function Details

[hide private]

DirDelta(path_iter, dirsig_fileobj_list)

source code

Produce tarblock diff given dirsig_fileobj_list and pathiter

dirsig_fileobj_list should either be a tar fileobj or a list of those, sorted so the most recent is last.

DirDelta_WriteSig(path_iter, sig_infp_list, newsig_outfp)

source code

Like DirDelta but also write signature into sig_fileobj

Like DirDelta, sig_infp_list can be a tar fileobj or a sorted list of those. A signature will only be written to newsig_outfp if it is different from (the combined) sig_infp_list.

DirFull(path_iter)

source code

Return a tarblock full backup of items in path_iter

A full backup is just a diff starting from nothing (it may be less elegant than using a standard tar file, but we can be sure that it will be easy to split up the tar and make the volumes the same sizes).

collate2iters(riter1, riter2)

source code

Collate two iterators.

The elements yielded by each iterator must be have an index variable, and this function returns pairs (elem1, elem2), (elem1, None), or (None, elem2) two elements in a pair will have the same index, and earlier indicies are yielded later than later indicies.

combine_path_iters(path_iter_list)

source code

Produce new iterator by combining the iterators in path_iter_list

This new iter will iterate every path that is in path_iter_list in order of increasing index. If multiple iterators in path_iter_list yield paths with the same index, combine_path_iters will discard all paths but the one yielded by the last path_iter.

This is used to combine signature iters, as the output will be a full up-to-date signature iter.

get_block_size(file_len)

source code

Return a reasonable block size to use on files of length file_len

If the block size is too big, deltas will be bigger than is necessary. If the block size is too small, making deltas and patching can take a really long time.

get_delta_iter(new_iter, sig_iter, sig_fileobj=None)

source code

Generate delta iter from new Path iter and sig Path iter.

For each delta path of regular file type, path.difftype with be set to "snapshot", "diff". sig_iter will probably iterate ROPaths instead of Paths.

If sig_fileobj is not None, will also write signatures to sig_fileobj.

log_delta_path(delta_path, new_path=None, stats=None)

source code

Look at delta path and log delta. Add stats if new_path is set