[PC-BSD Pbi-dev] Delta PBIs?

Jesse Smith jessefrgsmith at yahoo.ca
Mon Aug 23 06:25:44 PDT 2010

-----Original Message-----
From: Kris Moore <kris at pcbsd.org>
To: pbi-dev at lists.pcbsd.org
Subject: Re: [PC-BSD Pbi-dev] Delta PBIs?
Date: Mon, 23 Aug 2010 09:04:34 -0400

On 08/22/2010 20:05, Jesse Smith wrote:
> I think most of the effort could be automated. Something along the line
> of.
> 1. New PBI package is made for program ABC.
> 2. The old package is moved to a folder for "old versions".
> 3. The new version is placed in the repo.
> 4. A script figured out which files are different between the two and
> creates a delta PBI file.
> 5. The client's package manager checks to see if it has package ABC
> version current -1. If it does, then it grabs the delta bundle. If it is
> further out of date, it grabs the full version.
> Of course, it always sounds easier on (virtual) paper, but I think the
> over-all logic is fairly straight forward. Ideally, the packager
> wouldn't have to do anything extra, the script would rotate out old
> packages and create the delta. (And politicians would all be honest and
> little girls would all get free ponies while I'm at it.)
> - Jesse

I think its possible for sure, I'll have to do some digging into it to
see. All the files in the new PBI will be slightly different, just from
date-n-time stamps alone, but much of the contents would be the same.
I'll have to dig around and find a way to get a binary diff / delta of
the entire PBI directory, which only copies different parts of the
binary, not the full file :)


I think that even if you just copied the files which had different
contents, it would work. I mean, copy the entire file, not just the
difference between File A-version1.0 and File A-version1.1. This could
probably be done with the diff command. Because, I assume, most of the
files in a PBI will be the same between minor versions.

diff --brief file-1.0 file-1.1

This will return TRUE if the files are identical or FALSE if the
contents is different.

So a script that compares each file might do something like

diff --brief old-version/file new-version/file || cp new-version/file

Which would transfer a copy of the new version into the delta package,
if the file has changed since the previous version.

Just thinking out loud,

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