status of forked zlibs in rsync and zsync

[Jonathan Underwood]

2009/10/1 Toshio Kuratomi <a.badger at gmail.com>:
> On 10/01/2009 03:10 AM, Josephine Tannhäuser wrote:
>> 2009/9/14 Adam Williamson <awilliam at redhat.com>
>>
>>> Hi, everyone. We - the QA group - have recently been researching the
>>> feasibility of using zsync to reduce the size of live image downloads.
>>> This has hit a roadblock in the form of the problem where both rsync and
>>> zsync use forked zlibs rather than linking against the system copy.
>>>
>>
>> Imho, allow zsync for fedora. If you can solve the zlib-problem of rsync,
>> the problem of zsync will be solved as well, cause the integrity of zsync in
>> fedora fails on rsync-compatibility, which needs a forked zlib.
>>
> If you want it in, do the work.  I've outlined the possibilities several
> times:
>
> A) You're a coder and want to get your hands dirty with the rsync
> protocol.  Check out how librsync manages to use the system zlib and if
> possible to do this compatibly, apply it to zsync and rsync, possible as
> a build time option.  Push the changes upstream if possible.  If it's
> impossible to apply the librsync strategy, having a good explanation of
> what librsync is doing and why it can't work for rsync/zsync would be
> great for crossing this option off the list.
>

librsync is not wire compatible with rsync, and also hasn't kept up to
date with rsync protocol changes, so it may not be as straightforward
to lift ideas from librsync.