[platform-compare-dev] Patching for eclipse updates

[Dorian Birsan <birsan@xxxxxxxxxx>]

We're looking at ways to reduce the
number of bytes being downloaded by the Update Manager for feature updates/patches,
so we'd like to see if the current eclipse compare/merge/patch technology
can be used for this. 

Here is a scenario that we'd like to
support:
We need to update a plugin that has
changed in the following ways:
- file removed
- file added
- file has one line change
- jar file has one contained .class
file change
- zip file has one contained file changed.

- we should run a "create patch"
tool that creates a patch for the above.
- the update manager should be able
to read a patch and apply it.

To minimize the download size for the
above patch, we would like to, for example, not download the entire jar
or zip, but only the actually contained files that have changed inside
them.
Also, one of the constraints is that
we cannot pre-req any of the eclipse UI plugins.
Ideally, we could re-use some of the
classes that are already there, without having to implement IRangeComparator
or other related interfaces.

I noticed that our CVS support does
not work well with patching jars/zips, so I wonder if this is because our
compare/merge technology does not support it or because of CVS limitations.

Thanks,
-Dorian