Virtualization of the refs API

This is v2 of the patch series to virtualize the references API (though earlier patch series similar in spirit were submitted by Ronnie Sahlberg and David Turner). Thanks to Junio, Eric, and Ramsay for their comments about v1 [1].

Nobody pointed out any fundamental problems with v1, but this version includes the following improvements:

* In "rename_ref_available(): add docstring":

* Improve docstring as suggested by Junio.

* In "refs: create a base class "ref_store" for files_ref_store":

* Let main_ref_store and submodule_ref_stores be initialized implicitly rather than initializing them explicitly to NULL.

* Add docstrings for those two variables.

* Eliminate a temporary variable in files_downcast().

* In "resolve_gitlink_ref(): avoid memory allocation in many cases":

* Instead of keeping track of orig_len, after stripping off any trailing slashes check whether path[len - 1] is NUL.

* In "refs: add methods for reflog":

* Don't export files_reflog_iterator_begin() (suggested by Ramsay).

In addition, given that v1 was pretty old, I have rebased the patch series against the current upstream master. (The rebase was unproblematic.)

This patch series is also available from my GitHub fork [2] as branch "ref-store".

Michael

[1] http://public-inbox.org/git/[email protected]/t/
[2] https://github.com/mhagger/git

David Turner (8):
rename_ref_available(): add docstring
refs: add methods for reflog
refs: add method for initial ref transaction commit
refs: make delete_refs() virtual
refs: add methods to init refs db
refs: add method to rename refs
refs: make lock generic
refs: implement iteration over only per-worktree refs

Michael Haggerty (28):
resolve_gitlink_ref(): eliminate temporary variable
refs: rename struct ref_cache to files_ref_store
refs: create a base class "ref_store" for files_ref_store add_packed_ref(): add a files_ref_store argument get_packed_ref(): add a files_ref_store argument resolve_missing_loose_ref(): add a files_ref_store argument {lock,commit,rollback}_packed_refs(): add files_ref_store arguments
refs: reorder definitions
resolve_packed_ref(): rename function from resolve_missing_loose_ref() resolve_gitlink_packed_ref(): remove function read_raw_ref(): take a (struct ref_store *) argument resolve_ref_recursively(): new function resolve_gitlink_ref(): implement using resolve_ref_recursively() resolve_gitlink_ref(): avoid memory allocation in many cases resolve_gitlink_ref(): rename path parameter to submodule
refs: make read_raw_ref() virtual
refs: make verify_refname_available() virtual
refs: make pack_refs() virtual
refs: make create_symref() virtual
refs: make peel_ref() virtual
repack_without_refs(): add a files_ref_store argument lock_raw_ref(): add a files_ref_store argument commit_ref_update(): add a files_ref_store argument lock_ref_for_update(): add a files_ref_store argument lock_ref_sha1_basic(): add a files_ref_store argument split_symref_update(): add a files_ref_store argument files_ref_iterator_begin(): take a ref_store argument
refs: add method iterator_begin

Ronnie Sahlberg (2):
refs: add a backend method structure
refs: add a transaction_commit() method

 builtin/init-db.c    |  21 +-
 refs.c               | 309 +++++++++++++++++++++++++++-
 refs.h               |  13 +-
 refs/files-backend.c | 566 +++++++++++++++++++++++++++------------------------
 refs/refs-internal.h | 220 +++++++++++++++++---
 5 files changed, 812 insertions(+), 317 deletions(-)

2.9.3