Smart HTTP clients may request both multi_ack_detailed and no-done in
the same request to prevent the client from needing to send a "done"
line to the server in response to a server's "ACK %s ready".

For smart HTTP, this can save 1 full HTTP RPC in the fetch exchange,
improving overall latency when incrementally updating a client that
has not diverged very far from the remote repository.

Unfortuantely this capability cannot be enabled for the traditional
bi-directional connections.  multi_ack_detailed has the client sending
more "have" lines at the same time that the server is creating the
"ACK %s ready" and writing out the PACK stream, resulting in some race
conditions and/or deadlock, depending on how the pipe buffers are
implemented.  For very small updates, a server might actually be able
to send "ACK %s ready", then the PACK, and disconnect before the
client even finishes sending its first batch of "have" lines.  This
may cause the client to fail with a broken pipe exception.  To avoid
all of these potential problems, "no-done" is restricted only to the
smart HTTP variant of the protocol.

Change-Id: Ie0d0a39320202bc096fec2e97cb58e9efd061b2d
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

When fetching from a remote peer, consider all of the refs of any
alternate repository to be reachable locally, in addition to the refs
of the local repository.  This mirrors the push protocol and may avoid
unnecessary object transfer when the local repository is empty, but
its alternate and the remote share a lot of common history.

Junio C Hamano recently proposed a similar change to C Git's fetch
client, in order to work around a performance bug I identified when
fetching between two repositories that actually shared the same
alternate repository on the local system.

Change-Id: Iffb0b70e1223901ce2caac3b87ba7e0d6634d265
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

If the client is only following the remote repository and has not
created any new non-common commits, the client will wind up sending
a "have %s" line for each tag in the repository.  For some projects
like git.git, this is 339 tags and growing, resulting in more than
16 KiB needing to be POSTed over 12 HTTP requests.

Teach UploadPack (server side) to always execute the okToGiveUp()
logic at least once per negotiation round to determine if the server
can compute a pack right now.  If it can, shove in an "ACK %s ready"
message to tell the client this and try to prevent receiving ancient
tags in future negotiation rounds.

Teach BasePackFetchConnection (client side) to honor a "ACK %s ready"
from the remote and break out of its SEND_HAVE loop once the remote
knows it can create a pack.  This avoids sending the remaining 307
tags of git.git.

These two changes together reduce the number of HTTP RPCs from 13
down to 3 in order to fetch from git.git over smart HTTP.  If either
side is missing the change, the older behavior (and its 13 RPCs)
is used.

Change-Id: I64736318fd0abf9ee5e56bd0b737707adb580b37
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

If the RevFilter doesn't actually require the commit body,
we shouldn't reparse it if the body was disposed.  This happens
often inside of UploadPack during common ancestor negotation, the
RevWalk is reset and re-run over roughly the same commit space,
but the bodies are discarded because the commit message is not
relevant to the process.

Change-Id: I87b6b6a5fb269669867047698abf718d366bd002
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

By moving the logic that parses a pack stream from the network (or
a bundle) into a type that can be constructed by an ObjectInserter,
repository implementations have a chance to inject their own logic
for storing object data received into the destination repository.

The API isn't completely generic yet, there are still quite a few
assumptions that the PackParser subclass is storing the data onto
the local filesystem as a single file.  But its about the simplest
split of IndexPack I can come up with without completely ripping
the code apart.

Change-Id: I5b167c9cc6d7a7c56d0197c62c0fd0036a83ec6c
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

These classes need to be visible if an application wants to define
its own native pack based protocol embedded within another layer,
much like we already support for smart HTTP.

Change-Id: I7e2ac3ad01d15b94d340128a395fe0b2f560ff35
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Update a number of calling sites of RevWalk to ensure the walker's
internal ObjectReader is released after the walk is no longer used.
Because the ObjectReader is likely to hold onto a native resource
like an Inflater, we don't want to leak them outside of their
useful scope.

Where possible we also try to share ObjectReaders across several
walk pools, or between a walker and a PackWriter.  This permits
the ObjectReader to actually do some caching if it felt inclined
to do so.

Not everything was updated, we'll probably need to come back and
update even more call sites, but these are some of the biggest
offenders.  Test cases in particular aren't updated.  My plan is to
move most storage-agnostic tests onto some purely in-memory storage
solution that doesn't do compression.

Change-Id: I04087ec79faeea208b19848939898ad7172b6672
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This move isolates all of the local file specific implementation code
into a single package, where their package-private methods and support
classes are properly hidden away from the rest of the core library.

Because of the sheer number of files impacted, I have limited this
change to only the renames and the updated imports.

Change-Id: Icca4884e1a418f83f8b617d0c4c78b73d8a4bd17
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

The strings are externalized into the root resource bundles.
The resource bundles are stored under the new "resources" source
folder to get proper maven build.

Strings from tests are, in general, not externalized. Only in
cases where it was necessary to make the test pass the strings
were externalized. This was typically necessary in cases where
e.getMessage() was used in assert and the exception message was
slightly changed due to reuse of the externalized strings.

Change-Id: Ic0f29c80b9a54fcec8320d8539a3e112852a1f7b
Signed-off-by: Sasa Zivkov <sasa.zivkov@sap.com>

Any messages received on side band #2 that aren't scraped as a
progress message into our ProgressMonitor are now forwarded to a
buffer which is later included into the OperationResult object.
Application callers can use this buffer to present the additional
messages from the remote peer after the push or fetch operation
has concluded.

The smart push connections using the native send-pack/receive-pack
protocol now request side-band-64k capability if it is available
and forward any messages received through that channel onto this
message buffer.  This makes hook messages available over smart HTTP,
or even over SSH.

The SSH transport was modified to redirect the remote command's
stderr stream into the message buffer, interleaved with any data
received over side band #2.  Due to buffering between these two
different channels in the SSH channel mux itself the order of any
writes between the two cannot be ensured, but it tries to stay close.

The local fork transport was also modified to redirect the local
receive-pack's stderr into the message buffer, rather than going to
the invoking JVM's System.err.  This gives applications a chance
to log the local error messages, rather than needing to redirect
their JVM's stderr before startup.

To keep things simple, the application has to wait for the entire
operation to complete before it can see the messages.  This may
be a downside if the user is trying to debug a remote hook that is
blocking indefinitely, the user would need to abort the connection
before they can inspect the message buffer in any sort of UI built
on top of JGit.

Change-Id: Ibc215f4569e63071da5b7e5c6674ce924ae39e11
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Typically we refer to the raw InputStream (the stream without the
pkt-line headers on it) as rawIn, and the pkt-line header variant
as pckIn.  Refactor our fields to reflect that.  To ensure these
are actually the same underlying InputStream, we now create our own
PacketLineIn wrapper around the supplied raw InputStream.  Its a
very low-cost object since it has only the 4 byte length buffer.

Instead of hardcoding the header length as 5, use the constant from
SideBandOutputStream.  This makes it a bit more clear what we are
consuming, exactly here.

Change-Id: Iebd05538042913536b88c3ddc3adc3a86a841cc5
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

During fetch over http:// clients now try to take advantage of
the info/refs?service=git-upload-pack URL to determine if the
remote side will support a standard upload-pack command stream.
If so each block of 32 have lines is sent in one POST request,
prefixed by all of the 'want' lines and any previously discovered
common bases as 'have' lines.

During push over http:// clients now try to take advantage of
the info/refs?service=git-receive-pack URL to determine if the
remote side will support a standard receive-pack command stream.
If so, commands are sent along with their pack in a single HTTP
POST request.

Bug: 291002
Change-Id: I8c69b16ac15c442e1a4c3bd60b4ea1a47882b851
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

The multi_ack_detailed extension breaks out the "ACK %s continue" status
code into "ACK %s common" and "ACK %s ready" states, making it easier to
discover which objects are truely common, and which objects are simply
on a chain the server doesn't care learning about.

Change-Id: Ie8e907424cfbbba84996ca205d49eacf339f9d04
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

As discussed on the egit-dev mailing list, we prefer not to have
trailing whitespace in our source code.  Correct all currently
offending lines by trimming them.

Change-Id: I002b1d1980071084c0bc53242c8f5900970e6845
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>