Implement LfsProtocolServlet handling the "Git LFS v1 Batch API"
protocol [1]. Add a simple file system based LFS content store and the
debug-lfs-store command to simplify testing.

Introduce a LargeFileRepository interface to enable additional storage
implementation while reusing the same protocol implementation.

At the client side we have to configure the lfs.url, specify that
we use the batch API and we don't use authentication:

  [lfs]
	  url = http://host:port/lfs
	  batch = true
  [lfs "http://host:port/lfs"]
	  access = none

the git-lfs client appends the "objects/batch" to the lfs.url.

Hard code an Authorization header in the FileLfsRepository.getAction
because then git-lfs client will skip asking for credentials. It will
just forward the Authorization header from the response to the
download/upload request.

The FileLfsServlet supports file content storage for "Large File
Storage" (LFS) server as defined by the Github LFS API [2].

- upload and download of large files is probably network bound hence use
  an asynchronous servlet for good scalability
- simple object storage in file system with 2 level fan-out
- use LockFile to protect writing large objects against multiple
  concurrent uploads of the same object
- to prevent corrupt uploads the uploaded file is rejected if its hash
  doesn't match id given in URL

The debug-lfs-store command is used to run the LfsProtocolServlet and,
optionally, the FileLfsServlet which makes it easier to setup a
local test server.

[1]
https://github.com/github/git-lfs/blob/master/docs/api/http-v1-batch.md
[2] https://github.com/github/git-lfs/tree/master/docs/api

Bug: 472961
Change-Id: I7378da5575159d2195138d799704880c5c82d5f3
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Sasa Zivkov <sasa.zivkov@sap.com>

The Large File Storage extension specified by GitHub [1] uses SHA-256 to
compute the ID of large files stored by the extension. Hence implement a
SHA-256 abstraction similar to the SHA-1 abstraction used by JGit.

[1] https://git-lfs.github.com/

Bug: 470333
Change-Id: I3a95954543c8570d73929e55f4a884b55dbf1b7a
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Allow use of ArchiveCommand without depending on the jgit command-line
tools.

To avoid complicating the process of installing and upgrading JGit,
this does not add a dependency by the org.eclipse.jgit bundle on
commons-compress.  Instead, the caller is responsible for registering
any formats they want to use by calling ArchiveCommand.registerFormat.

This patch puts functionality that requires an archiver into a
separate org.eclipse.jgit.archive bundle for people who want it.  One
can use it by calling ArchiveCommand.registerFormat directly to
register its formats or by relying on OSGi class loading to load
org.eclipse.jgit.archive.FormatActivator, which takes care of
registration automatically.

Once the appropriate formats are registered, you can make a tar or zip
from a git tree object as follows:

	ArchiveCommand cmd = git.archive();
	try {
		cmd.setTree(tree).setFormat(fmt).setOutputStream(out).call();
	} finally {
		cmd.release();
	}

Change-Id: I418e7e7d76422dc6f010d0b3b624d7bec3b20c6e

Note the the settings are slightly less restrictive for test bundles.
-Also cleanup a couple of malformed javadocs
-Update compiler warnings/errors to include default values from Juno
-We now flag diagnosed null dereference as error. We didn't do that
 earlier because of some false positives.

Change-Id: I58386d63164e65d3d8d1998da3390d99bdc7381a
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

This way we depend upon the MANIFEST.MF to define our classpath
and our build will act more like any other OSGI bundle build.

Change-Id: I9e1f1f5a0bccb0ab0e39e49b75fb400fea446619
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This new UI bundle contains the org.eclipse.jgit.awtui package,
which was moved out of the org.eclipse.jgit bundle.

org.eclipse.jgit.pgm depends on org.eclipse.jgit.ui, so we need
to update the classpath and make_jgit.sh to include it.

This move takes the awtui classes out of the Maven build, which
means we are no longer able to distribute these classes to our
downstream Maven customers.  The entire Maven package structure
needs to be overhauled so that Eclipse bundle matches 1:1 with the
Maven artifact.

Bug: https://bugs.eclipse.org/291124
Change-Id: Ibf1a9968387e3d11fdce54592f710ec4cc7f1ddb
Signed-off-by: Mykola Nikishov <mn@mn.com.ua>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>