Support LFS protocol and a file system based LFS storage

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>

1 files changed, 6 insertions, 0 deletions

diff --git a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
index b4b1261b37..544e234e3a 100644
--- a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
+++ b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
@@ -125,6 +125,7 @@ metaVar_remoteName=name
 metaVar_revision=REVISION
 metaVar_seconds=SECONDS
 metaVar_service=SERVICE
+metaVar_lfsStorage=STORAGE
 metaVar_treeish=tree-ish
 metaVar_uriish=uri-ish
 metaVar_url=URL
@@ -218,6 +219,10 @@ usage_DisplayTheVersionOfJgit=Display the version of jgit
 usage_Gc=Cleanup unnecessary files and optimize the local repository
 usage_Glog=View commit history as a graph
 usage_IndexPack=Build pack index file for an existing packed archive
+usage_LFSDirectory=Directory to store large objects
+usage_LFSPort=Server http port
+usage_LFSRunStore=fs: store lfs objects in file system
+usage_LFSStoreUrl=URL of the LFS store
 usage_LongFormat=Always output the long format
 usage_LsRemote=List references in a remote repository
 usage_lsRemoteHeads=Show only refs starting with refs/heads
@@ -347,6 +352,7 @@ usage_resetReference=Reset to given reference name
 usage_resetHard=Resets the index and working tree
 usage_resetSoft=Resets without touching the index file nor the working tree
 usage_resetMixed=Resets the index but not the working tree
+usage_runLfsStore=Run LFS Store in a given directory
 usage_setTheGitRepositoryToOperateOn=set the git repository to operate on
 usage_show=display one commit
 usage_showRefNamesMatchingCommits=Show ref names matching commits