Introduce support for the pre-commit hook into JGit, along with the
--no-verify commit command option to bypass it when rebasing /
cherry-picking.

Change-Id: If86df98577fa56c5c03d783579c895a38bee9d18
Signed-off-by: Laurent Goubet <laurent.goubet@obeo.fr>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Bug: 361548
CQ: 6243
Change-Id: I08e1369e142bb19f42a8d7bbb5a7d062cc8533fc
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

Implemented the initial version of a cherry-pick command.
A correct error handling is missing (what happens if the
checkout fails, the cherry-pick leads to conflicts etc).
But straightforward cherry-picks works.

Change-Id: I235c0eb3a7a2d5bdfe40400f1deed06f29d746e1
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Similar to what we did with the file code, move the pack writer
into its own package so the related classes and their package
private methods are hidden from the rest of the library.

Change-Id: Ic1b5c7c8c8d266e90c910d8d68dfc8e93586854f
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Output of selected reuses is refactored to use a new ObjectReuseAsIs
interface that extends the ObjectReader.  This interface allows the
reader to control how it performs the reuse into the output stream,
but also allows it to throw an exception to request the writer to
find a different candidate representation.

The PackFile reuse code was overhauled, cleaning up the APIs so they
aren't exposed in the object loader, but instead are now a single
method on the PackFile itself.  The reuse algorithm was changed to do
a data verification pass, followed by the copy pass to the output.
This permits us to work around a corrupt object in a pack file by
seeking another copy of that object when this one is bad.

The reuse code was also optimized for the common case, where the
in-pack representation is under 16 KiB.  In these smaller cases
data is sent to the pack writer more directly, avoiding some copying.

Change-Id: I6350c2b444118305e8446ce1dfd049259832bcca
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Per CQ 3448 this is the initial contribution of the JGit project
to eclipse.org.  It is derived from the historical JGit repository
at commit 3a2dd9921c.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>