This adds the reftable library, and hooks it up as a ref backend.

At this point, I am mainly interested in feedback on the spots marked with
XXX in the Git source code.

v3

 * passes gitgitgadget CI.

Han-Wen Nienhuys (5):
  refs.h: clarify reflog iteration order
  create .git/refs in files-backend.c
  refs: document how ref_iterator_advance_fn should handle symrefs
  Add reftable library
  Reftable support for git-core

 Makefile                |   24 +-
 builtin/init-db.c       |   49 +-
 cache.h                 |    2 +
 refs.c                  |   20 +-
 refs.h                  |    5 +-
 refs/files-backend.c    |    6 +
 refs/refs-internal.h    |    6 +
 refs/reftable-backend.c |  880 +++++++++++++++++++++++++++++++
 reftable/LICENSE        |   31 ++
 reftable/README.md      |   19 +
 reftable/VERSION        |    5 +
 reftable/basics.c       |  196 +++++++
 reftable/basics.h       |   37 ++
 reftable/block.c        |  401 ++++++++++++++
 reftable/block.h        |   71 +++
 reftable/blocksource.h  |   20 +
 reftable/bytes.c        |    0
 reftable/config.h       |    1 +
 reftable/constants.h    |   27 +
 reftable/dump.c         |   97 ++++
 reftable/file.c         |   97 ++++
 reftable/iter.c         |  229 ++++++++
 reftable/iter.h         |   56 ++
 reftable/merged.c       |  286 ++++++++++
 reftable/merged.h       |   34 ++
 reftable/pq.c           |  114 ++++
 reftable/pq.h           |   34 ++
 reftable/reader.c       |  708 +++++++++++++++++++++++++
 reftable/reader.h       |   52 ++
 reftable/record.c       | 1107 +++++++++++++++++++++++++++++++++++++++
 reftable/record.h       |   79 +++
 reftable/reftable.h     |  399 ++++++++++++++
 reftable/slice.c        |  199 +++++++
 reftable/slice.h        |   39 ++
 reftable/stack.c        |  983 ++++++++++++++++++++++++++++++++++
 reftable/stack.h        |   40 ++
 reftable/system.h       |   55 ++
 reftable/tree.c         |   66 +++
 reftable/tree.h         |   24 +
 reftable/writer.c       |  623 ++++++++++++++++++++++
 reftable/writer.h       |   46 ++
 reftable/zlib-compat.c  |   92 ++++
 repository.c            |    2 +
 repository.h            |    3 +
 setup.c                 |   12 +-
 45 files changed, 7248 insertions(+), 28 deletions(-)
 create mode 100644 refs/reftable-backend.c
 create mode 100644 reftable/LICENSE
 create mode 100644 reftable/README.md
 create mode 100644 reftable/VERSION
 create mode 100644 reftable/basics.c
 create mode 100644 reftable/basics.h
 create mode 100644 reftable/block.c
 create mode 100644 reftable/block.h
 create mode 100644 reftable/blocksource.h
 create mode 100644 reftable/bytes.c
 create mode 100644 reftable/config.h
 create mode 100644 reftable/constants.h
 create mode 100644 reftable/dump.c
 create mode 100644 reftable/file.c
 create mode 100644 reftable/iter.c
 create mode 100644 reftable/iter.h
 create mode 100644 reftable/merged.c
 create mode 100644 reftable/merged.h
 create mode 100644 reftable/pq.c
 create mode 100644 reftable/pq.h
 create mode 100644 reftable/reader.c
 create mode 100644 reftable/reader.h
 create mode 100644 reftable/record.c
 create mode 100644 reftable/record.h
 create mode 100644 reftable/reftable.h
 create mode 100644 reftable/slice.c
 create mode 100644 reftable/slice.h
 create mode 100644 reftable/stack.c
 create mode 100644 reftable/stack.h
 create mode 100644 reftable/system.h
 create mode 100644 reftable/tree.c
 create mode 100644 reftable/tree.h
 create mode 100644 reftable/writer.c
 create mode 100644 reftable/writer.h
 create mode 100644 reftable/zlib-compat.c

base-commit: 5b0ca878e008e82f91300091e793427205ce3544

Submitted-As: https://lore.kernel.org/git/pull.539.v4.git.1581029756.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.539.git.1579808479.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.539.v2.git.1580134944.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.539.v3.git.1580848060.gitgitgadget@gmail.com