Add built-in LFS smudge filter for local case

Adds a JGit built-in implementation of the "git lfs smudge" filter. This
filter should do the same as the one described in [1] besides that it
only supports the local case when the lfs objects are already present in
the media directory. Remote cases where download of LFS objects from an
LFS server is needed will be done in a later commit.

[1] https://github.com/github/git-lfs/blob/master/docs/man/git-lfs-smudge.1.ronn

Change-Id: I8ff661d4edd3667ef7f86f3b4fa33e568eb4c8f4

1 files changed, 5 insertions, 0 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java
index 1f37833a41..16ec1463c9 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/AddCommand.java
@@ -224,6 +224,11 @@ public class AddCommand extends GitCommand<DirCache> {
 					entry.setLength(f.getEntryLength());
 					entry.setLastModified(f.getEntryLastModified());
 					long len = f.getEntryContentLength();
+					// We read and filter the content multiple times.
+					// f.getEntryContentLength() reads and filters the input and
+					// inserter.insert(...) does it again. That's because an
+					// ObjectInserter needs to know the length before it starts
+					// inserting. TODO: Fix this by using Buffers.
 					try (InputStream in = f.openEntryStream()) {
 						ObjectId id = inserter.insert(OBJ_BLOB, len, in);
 						entry.setObjectId(id);