Teach UploadPack to take a provider of URIs corresponding to cached
packs. When fetching, if the client supports the packfile-uri feature,
and if such a cached pack were to be streamed, instead send the
corresponding URI.

This packfile-uri feature is implemented in the jt/fetch-cdn-offload
branch of Git. There is interest in this feature [1], but it is not yet
merged.

[1] https://public-inbox.org/git/cover.1552073690.git.jonathantanmy@google.com/

Change-Id: I9a32dae131c9c56ad2ff4a8a9638ae3b5e44dc15
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>

Allow the client to specify "sideband-all" in a fetch v2 request,
indicating that the whole response is to be multiplexed (with a sideband
indicator on every non-flush and non-delim pkt) instead of only the
packfile being multiplexed. This allows, for example, progress messages
to be sent at any point in the response.

This implements the "sideband-all" feature documented in
Documentation/technical/protocol-v2.txt in Git.

Change-Id: I3e7f21c88ff0982b1b7ebb09c9ad6c742c4483c8
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>

This increases type-safety and is ground work for support of the
"tree:<depth>" filter.

Change-Id: Id19eacdcdaddb9132064c642f6d554b1060efe9f
Signed-off-by: Matthew DeVore <matvore@gmail.com>

The visibility change was merged after 5.3 release. The @since line
is wrong.

Fixing it in a new commit looks like the easiest way forward.

Change-Id: I6f72a9e684e99a4440cda1eb532c22b4b7bbdea5
Signed-off-by: Ivan Frade <ifrade@google.com>

There are valid cases where a hook, invoked by ProtocolV2Hook
and probably implemented in a different package, is interested
in knowing the wanted refs in the request.

Increase visibility to public in the wanted-ref method.

Change-Id: I5da085ac7af4c396c1cb85e630f40a57fc70b33e
Signed-off-by: Ivan Frade <ifrade@google.com>

ProtocolV2Parser explains:

  // TODO(ifrade): This validation should be done after the
  // protocol parsing. It is not a protocol problem asking for an
  // unexisting ref and we wouldn't need the ref database here.

Do so.  This way all ref database accesses are in one place, in the
UploadPack class.

No user-visible change intended --- this is just to make the code
easier to manipulate.

Change-Id: I68e87dff7b9a63ccc169bd0836e8e8baaf5d1048
Signed-off-by: Jonathan Nieder <jrn@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

UploadPack.getPeerUserAgent() doesn't produce the expected results for
protocol v2 requests. In v2, the agent reported in the request (in an
"agent=" line) is not in the clientCapabilities but in a field on its
own. This makes getPeerUserAgent default to the transport user agent.

Making "agent" a shared property between protocol v0/v1 and v2 fixes the
problem, simplifies the function and harmonizes the implementation
between protocol versions.

In a follow up commit the "agent" will be identified on parsing time,
instead of taking it from the client capabilities.

Change-Id: Idf9825ec4e0b81a1458c8e3701f3e28aafd8a32a
Signed-off-by: Ivan Frade <ifrade@google.com>

In protocol v2, a command request can be followed by server options
(lines like "agent=<>" and "server-option=<>"), but current code
doesn't accept those lines.

Advertise the "server-option" capability, parse the lines and add
them to the request objects.

Other code in JGit can see this options and act accordingly via the
protocol v2 hooks.

This should not require any change in the client side.

Change-Id: If3946390f9cc02d29644b6ca52534b6f757bda9f
Signed-off-by: Ivan Frade <ifrade@google.com>

These properties are protocol v2 specific, but they have clear default
no-op values and having them in the common superclass simplifies client
code.

Move properties deepenSince and deepenNotRefs up to FetchRequest. In
FetchV0Request, they are initialized with their no-op values (0 for
deepenSince and empty list for deepenNotRefs)

Change-Id: I9d46a6dfbe29ebd794b5a6482033cdc70d411a23
Signed-off-by: Ivan Frade <ifrade@google.com>

Mark reference fields as final, annotate constructor parameters and
getters as @NonNull when appropiate and assert the incoming references
are non-null.

Change-Id: I0ef9a513a99313bf461fe9629ce6cc8b409bdedb
Signed-off-by: Ivan Frade <ifrade@google.com>

Some code apply to both, v1 and v2 requests, so it should receive
just a request instance.

Move all common fields to an abstract superclass that can be passed
to "version neutral" functions.

Change-Id: I47c22fb12065bc93767f78175e2b36cc43ccb5c5
Signed-off-by: Ivan Frade <ifrade@google.com>

In FetchV0Request, the fields "wantsIds" and "options" are called
"wantIds" and "clientCapabilities". Those names describe them better.

Rename FetchV2Request fields to follow fetch v0. This will make easier
to extract a superclass later.

Take also the chance to polish the javadoc.

Change-Id: Ia17dbbab8084f39cc529fef9ca5c65e189073767
Signed-off-by: Ivan Frade <ifrade@google.com>

This fetch parameter is called deepen-since in the protocol.  Call it
the same thing in the request object to make the code easier to reason
about.

This doesn't touch UploadPack#shallowSince, which is likely to be
eliminated altogether in a later patch anyway.

Change-Id: I8ef34bc7ad12fae3a9057ae951367cc024e1a1cb
Suggested-by: Ivan Frade <ifrade@google.com>
Signed-off-by: Jonathan Nieder <jrn@google.com>

There is an extra 'd' in deependNotRefs.  Noticed during code review.

Change-Id: I93d8d7951fe5c351b62e23bdf5bad0ebd631017d
Signed-off-by: Jonathan Nieder <jrn@google.com>

Make "doneReceived" a member of the fetch request. It indicates if the
"done" line has been received (so it makes sense there) and makes all
the code after the parsing depend only on the request.

Rename "shallowExcludeRefs" to "deepenNot". Those refs come in
"deepen-not" lines in the protocol, and this name makes clearer the
intention.

Change-Id: I7bec65de04930277266491d278de7c3af7d8cbe6
Signed-off-by: Ivan Frade <ifrade@google.com>

This makes it symmetrical with ls-refs operation and gives the
instantiator of UploadPack the chance to run some code after parsing
the protocol and before any actual work for the fetch starts.

Request and Builder methods keep the naming in the original code to
make this change just about request encapsulation and hook invocation.
They are package-private for now to allow further improvements.

Change-Id: I5ad585c914d3a5f23b11c8251803faa224beffb4
Signed-off-by: Ivan Frade <ifrade@google.com>