[PATCH 0/6] Refactor fetch negotiation into its own API

[Jonathan Tan <jonathantanmy@google.com>]

Both Stefan and Junio have suggested in [1] that I create a new
negotiation API first, then implement a new algorithm, and I perhaps too
optimistically said that doing it all at once should be fine. Extracting
the API turns out to be more difficult than expected. Here are the
patches that do that, without any new algorithms.

The patches include 3 patches that eliminate some minor differences
between protocol v0 and protocol v2, then 3 patches that implement the
API. I tried to write tests for all of the former 3, but could only do
so for one, because I didn't know how to construct situations that show
a difference in behavior as an effect of such a code change (or, if such
a situation is possible without custom transports). As for the latter 3,
these are refactorings with no user-visible changes, and I have tried to
write them in such a way that it is clear to a reviewer that the same
functionality and logic is present before and after, and that they are
just organized better.

Overall, these do not change much functionality, but would be a good
base for contributors (myself and even others) to experiment with
negotiation algorithms.

[1] https://public-inbox.org/git/20180521204340.260572-1-jonathantanmy@google.com/

Jonathan Tan (6):
  fetch-pack: clear marks before everything_local()
  fetch-pack: truly stop negotiation upon ACK ready
  fetch-pack: in protocol v2, enqueue commons first
  fetch-pack: make negotiation-related vars local
  fetch-pack: move common check and marking together
  fetch-pack: introduce negotiator API

 Makefile              |   2 +
 fetch-negotiator.c    |   7 ++
 fetch-negotiator.h    |  45 +++++++++
 fetch-pack.c          | 222 ++++++++++++------------------------------
 negotiator/default.c  | 173 ++++++++++++++++++++++++++++++++
 negotiator/default.h  |   8 ++
 object.h              |   3 +-
 t/t5500-fetch-pack.sh |  35 +++++++
 8 files changed, 332 insertions(+), 163 deletions(-)
 create mode 100644 fetch-negotiator.c
 create mode 100644 fetch-negotiator.h
 create mode 100644 negotiator/default.c
 create mode 100644 negotiator/default.h

-- 
2.17.0.768.g1526ddbba1.dirty