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From Stefan Bodewig <bode...@apache.org>
Subject Re: [compress] Pack200
Date Wed, 14 Sep 2011 15:16:26 GMT
On 2011-09-05, Stefan Bodewig wrote:

> On 2011-09-05, Emmanuel Bourg wrote:

>> That looks interesting. Does it provide a repack mode suitable for
>> signing compressed jars?

> I assume you mean

> ,----
> | Note that packing and unpacking a JAR will in general alter the bytewise
> | contents of classfiles in the JAR. This means that packing and unpacking
> | will in general invalidate any digital signatures which rely on bytewise
> | images of JAR elements. In order both to sign and to pack a JAR, you
> | must first pack and unpack the JAR to "normalize" it, then compute
> | signatures on the unpacked JAR elements, and finally repack the signed
> | JAR. Both packing steps should use precisely the same options, and the
> | segment limit may also need to be set to "-1", to prevent accidental
> | variation of segment boundaries as class file sizes change slightly.
> `----

> as in
> <http://download.oracle.com/javase/1.5.0/docs/api/java/util/jar/Pack200.Packer.html>

> I think the "normalization" step could be part of a util class inside
> the package.  Some utility method that takes a JAR, packs it and unpacks
> it again to a new jar that would then need to get signed.  Signing
> itself seems outside of compress' scope to me.

Emmanuel, is the Pack200Utils.normalize method I've just committed what
you've been looking for?

Stefan

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