[PATCH v4 00/20] refs backend

Changes to this version: re-rolled on top of pu as-of 9db66d9f1aa.

Bug fixes include: For submodules: memory leaks; segfault on bad config. (thanks to Peff) In symref splitting: check that would always succeed (thanks to Peff) A bogus double-declaration of a var (thanks to Ramsay Jones) Two memory leaks (thanks to Thomas Gummerer) An unused var (thanks to Duy Nguyen)

Other improvements are:
Strings prepped for 18n (thanks to Duy Nguyen)
Cleaner submodule handling (thanks to Peff)
Whitelisting instead of blacklisting in git-new-workdir (thanks to
  Thomas Gummerer)
Allow older gits to recognize lmdb-backend git repos (thanks to Duy Nguyen)
Tab completion and cleaner commit messages (thanks SZEDER Gábor)
Removed some #ifdefs, moving all backend setup to one place (thanks to Duy
Nguyen)

Thanks to all for reviews.

David Turner (18):
  refs: add do_for_each_per_worktree_ref
  refs: add methods for reflog
  refs: add method for initial ref transaction commit
  refs: add method for delete_refs
  refs: add methods to init refs db
  refs: add method to rename refs
  refs: make lock generic
  refs: move duplicate check to common code
  refs: allow log-only updates
  refs: resolve symbolic refs first
  refs: always handle non-normal refs in files backend
  init: allow alternate ref strorage to be set for new repos
  refs: check submodules ref storage config
  clone: allow ref storage backend to be set for clone
  svn: learn ref-storage argument
  refs: add register_ref_storage_backends()
  refs: add LMDB refs storage backend
  refs: tests for lmdb backend

Ronnie Sahlberg (3):
  refs: add a backend method structure with transaction functions
  refs: add methods for misc ref operations
  refs: add methods for the ref iterators

 .gitignore                                     |    1 +
 Documentation/config.txt                       |    7 +
 Documentation/git-clone.txt                    |    6 +
 Documentation/git-init-db.txt                  |    2 +-
 Documentation/git-init.txt                     |    7 +-
 Documentation/technical/refs-lmdb-backend.txt  |   52 +
 Documentation/technical/repository-version.txt |    5 +
 Makefile                                       |   12 +
 builtin/clone.c                                |    5 +
 builtin/init-db.c                              |   57 +-
 builtin/submodule--helper.c                    |    2 +-
 cache.h                                        |    2 +
 config.c                                       |   25 +
 configure.ac                                   |   33 +
 contrib/completion/git-completion.bash         |    6 +-
 contrib/workdir/git-new-workdir                |    3 +
 git-submodule.sh                               |   13 +
 git-svn.perl                                   |    6 +-
 path.c                                         |   29 +-
 refs.c                                         |  486 +++++-
 refs.h                                         |   21 +
 refs/files-backend.c                           |  404 ++---
 refs/lmdb-backend.c                            | 2052 ++++++++++++++++++++++++
 refs/refs-internal.h                           |  128 +-
 setup.c                                        |   23 +-
 t/t0001-init.sh                                |   25 +
 t/t1460-refs-lmdb-backend.sh                   | 1109 +++++++++++++
 t/t1470-refs-lmdb-backend-reflog.sh            |  359 +++++
 t/t1480-refs-lmdb-submodule.sh                 |   85 +
 t/test-lib.sh                                  |    1 +
 test-refs-lmdb-backend.c                       |   64 +
 transport.c                                    |    7 +-
 32 files changed, 4825 insertions(+), 212 deletions(-)
 create mode 100644 Documentation/technical/refs-lmdb-backend.txt
 create mode 100644 refs/lmdb-backend.c
 create mode 100755 t/t1460-refs-lmdb-backend.sh
 create mode 100755 t/t1470-refs-lmdb-backend-reflog.sh
 create mode 100755 t/t1480-refs-lmdb-submodule.sh
 create mode 100644 test-refs-lmdb-backend.c