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Nguyễn Thái Ngọc Duy 7d2df051d0 refs: add new ref-store api
This is not meant to cover all existing API. It adds enough to test ref
stores with the new test program test-ref-store, coming soon and to be
used by files-backend.c.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-14 03:53:25 -07:00
Nguyễn Thái Ngọc Duy 9e7ec634a1 files-backend: replace submodule_allowed check in files_downcast()
files-backend.c is unlearning submodules. Instead of having a specific
check for submodules to see what operation is allowed, files backend
now takes a set of flags at init. Each operation will check if the
required flags is present before performing.

For now we have four flags: read, write and odb access. Main ref store
has all flags, obviously, while submodule stores are read-only and have
access to odb (*).

The "main" flag stays because many functions in the backend calls
frontend ones without a ref store, so these functions always target the
main ref store. Ideally the flag should be gone after ref-store-aware
api is in place and used by backends.

(*) Submodule code needs for_each_ref. Try take REF_STORE_ODB flag
out. At least t3404 would fail. The "have access to odb" in submodule is
a bit hacky since we don't know from he whether add_submodule_odb() has
been called.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-14 03:53:18 -07:00
Nguyễn Thái Ngọc Duy 5d0bc90e5d refs: move submodule code out of files-backend.c
files-backend is now initialized with a $GIT_DIR. Converting a submodule
path to where real submodule gitdir is located is done in get_ref_store().

This gives a slight performance improvement for submodules since we
don't convert submodule path to gitdir at every backend call like
before. We pay that once at ref-store creation.

More cleanup in files_downcast() and files_assert_main_repository()
follows shortly. It's separate to keep noises from this patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:40 -07:00
Nguyễn Thái Ngọc Duy 077be78d7f refs.c: make get_main_ref_store() public and use it
get_ref_store() will soon be renamed to get_submodule_ref_store().
Together with future get_worktree_ref_store(), the three functions
provide an appropriate ref store for different operation modes. New APIs
will be added to operate directly on ref stores.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy f57f37e2e1 files-backend: remove the use of git_path()
Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
deciding what goes where (*). The end goal is to pass $GIT_DIR only. A
refs "view" of a linked worktree is a logical ref store that combines
two files backends together.

(*) Not entirely true since strbuf_git_path_submodule() still does path
translation underneath. But that's for another patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 19e02f4f46 files-backend: add and use files_ref_path()
Keep repo-related path handling in one place. This will make it easier
to add submodule/multiworktree support later.

This automatically adds the "if submodule then use the submodule version
of git_path" to other call sites too. But it does not mean those
operations are submodule-ready. Not yet.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 802de3da07 files-backend: add and use files_reflog_path()
Keep repo-related path handling in one place. This will make it easier
to add submodule/multiworktree support later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy a5c1efd693 files-backend: move "logs/" out of TMP_RENAMED_LOG
This makes reflog path building consistent, always in the form of

    strbuf_git_path(sb, "logs/%s", refname);

It reduces the mental workload a bit in the next patch when that
function call is converted.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy e9dcc3054f files-backend: convert git_path() to strbuf_git_path()
git_path() and friends are going to be killed in files-backend.c in near
future. And because there's a risk with overwriting buffer in
git_path(), let's convert them all to strbuf_git_path(). We'll have
easier time killing/converting strbuf_git_path() then because we won't
have to worry about memory management again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 0a3f07d6c0 files-backend: make sure files_rename_ref() always reach the end
This is a no-op patch. It prepares the function so that we can release
resources (to be added later in this function) before we return.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 33dfb9f3f2 files-backend: add and use files_packed_refs_path()
Keep repo-related path handling in one place. This will make it easier
to add submodule/multiworktree support later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 1eab194bf0 files-backend: delete dead code in files_init_db()
safe_create_dir() can do adjust_shared_perm() internally, and init-db
has always created 'refs' in shared mode since the beginning,
af6e277c5e (git-init-db: initialize shared repositories with --shared -
2005-12-22). So this code looks like extra adjust_shared_perm calls are
unnecessary.

And they are. But let's see why there are here in the first place.

This code was added in 6fb5acfd8f (refs: add methods to init refs db -
2016-09-04). From the diff alone this looks like a faithful refactored
code from init-db.c. But there is a subtle difference:

Between the safe_create_dir() block and adjust_shared_perm() block in
the old init-db.c, we may copy/recreate directories from the repo
template. So it makes sense that adjust_shared_perm() is re-executed
then to fix potential permission screwups.

After 6fb5acfd8f, refs dirs are created after template is copied. Nobody
will change directory permission again. So the extra adjust_shared_perm()
is redudant. Delete them.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 4f43731268 files-backend.c: delete dead code in files_ref_iterator_begin()
It's not in the diff context, but files_downcast() is called before this
check. If "refs" is NULL, we would have segfaulted before reaching the
check here. And we should never see NULL refs in backend code (frontend
should have caught it).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Nguyễn Thái Ngọc Duy 11f8457fb9 files-backend: make files_log_ref_write() static
Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
but probably never used outside refs-internal.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-27 10:23:39 -07:00
Junio C Hamano e1fae93019 Merge branch 'bc/object-id'
"uchar [40]" to "struct object_id" conversion continues.

* bc/object-id:
  wt-status: convert to struct object_id
  builtin/merge-base: convert to struct object_id
  Convert object iteration callbacks to struct object_id
  sha1_file: introduce an nth_packed_object_oid function
  refs: simplify parsing of reflog entries
  refs: convert each_reflog_ent_fn to struct object_id
  reflog-walk: convert struct reflog_info to struct object_id
  builtin/replace: convert to struct object_id
  Convert remaining callers of resolve_refdup to object_id
  builtin/merge: convert to struct object_id
  builtin/clone: convert to struct object_id
  builtin/branch: convert to struct object_id
  builtin/grep: convert to struct object_id
  builtin/fmt-merge-message: convert to struct object_id
  builtin/fast-export: convert to struct object_id
  builtin/describe: convert to struct object_id
  builtin/diff-tree: convert to struct object_id
  builtin/commit: convert to struct object_id
  hex: introduce parse_oid_hex
2017-03-17 13:50:25 -07:00
Junio C Hamano c13c783c9d Merge branch 'km/delete-ref-reflog-message'
"git update-ref -d" and other operations to delete references did
not leave any entry in HEAD's reflog when the reference being
deleted was the current branch.  This is not a problem in practice
because you do not want to delete the branch you are currently on,
but caused renaming of the current branch to something else not to
be logged in a useful way.

* km/delete-ref-reflog-message:
  branch: record creation of renamed branch in HEAD's log
  rename_ref: replace empty message in HEAD's log
  update-ref: pass reflog message to delete_ref()
  delete_ref: accept a reflog message argument
2017-02-27 13:57:18 -08:00
Junio C Hamano 466be3e1de Merge branch 'mh/submodule-hash'
Code and design clean-up for the refs API.

* mh/submodule-hash:
  read_loose_refs(): read refs using resolve_ref_recursively()
  files_ref_store::submodule: use NULL for the main repository
  base_ref_store_init(): remove submodule argument
  refs: push the submodule attribute down
  refs: store submodule ref stores in a hashmap
  register_ref_store(): new function
  refs: remove some unnecessary handling of submodule == ""
  refs: make some ref_store lookup functions private
  refs: reorder some function definitions
2017-02-27 13:57:15 -08:00
Junio C Hamano 3ad8b5bf26 Merge branch 'mh/ref-remove-empty-directory'
Deletion of a branch "foo/bar" could remove .git/refs/heads/foo
once there no longer is any other branch whose name begins with
"foo/", but we didn't do so so far.  Now we do.

* mh/ref-remove-empty-directory: (23 commits)
  files_transaction_commit(): clean up empty directories
  try_remove_empty_parents(): teach to remove parents of reflogs, too
  try_remove_empty_parents(): don't trash argument contents
  try_remove_empty_parents(): rename parameter "name" -> "refname"
  delete_ref_loose(): inline function
  delete_ref_loose(): derive loose reference path from lock
  log_ref_write_1(): inline function
  log_ref_setup(): manage the name of the reflog file internally
  log_ref_write_1(): don't depend on logfile argument
  log_ref_setup(): pass the open file descriptor back to the caller
  log_ref_setup(): improve robustness against races
  log_ref_setup(): separate code for create vs non-create
  log_ref_write(): inline function
  rename_tmp_log(): improve error reporting
  rename_tmp_log(): use raceproof_create_file()
  lock_ref_sha1_basic(): use raceproof_create_file()
  lock_ref_sha1_basic(): inline constant
  raceproof_create_file(): new function
  safe_create_leading_directories(): set errno on SCLD_EXISTS
  safe_create_leading_directories_const(): preserve errno
  ...
2017-02-27 13:57:12 -08:00
brian m. carlson 43bc3b6cee refs: simplify parsing of reflog entries
The current code for reflog entries uses a lot of hard-coded constants,
making it hard to read and modify.  Use parse_oid_hex and two temporary
variables to simplify the code and reduce the use of magic constants.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-22 10:12:15 -08:00
brian m. carlson 9461d27240 refs: convert each_reflog_ent_fn to struct object_id
Make each_reflog_ent_fn take two struct object_id pointers instead of
two pointers to unsigned char.  Convert the various callbacks to use
struct object_id as well.  Also, rename fsck_handle_reflog_sha1 to
fsck_handle_reflog_oid.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-22 10:12:15 -08:00
Kyle Meyer 39ee4c6c2f branch: record creation of renamed branch in HEAD's log
Renaming the current branch adds an event to the current branch's log
and to HEAD's log.  However, the logged entries differ.  The entry in
the branch's log represents the entire renaming operation (the old and
new hash are identical), whereas the entry in HEAD's log represents
the deletion only (the new sha1 is null).

Extend replace_each_worktree_head_symref(), whose only caller is
branch_rename(), to take a reflog message argument.  This allows the
creation of the new ref to be recorded in HEAD's log.  As a result,
the renaming event is represented by two entries (a deletion and a
creation entry) in HEAD's log.

It's a bit unfortunate that the branch's log and HEAD's log now
represent the renaming event in different ways.  Given that the
renaming operation is not atomic, the two-entry form is a more
accurate representation of the operation and is more useful for
debugging purposes if a failure occurs between the deletion and
creation events.  It would make sense to move the branch's log to the
two-entry form, but this would involve changes to how the rename is
carried out and to how the update flags and reflogs are processed for
deletions, so it may not be worth the effort.

Based-on-patch-by: Jeff King <peff@peff.net>
Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-20 22:04:47 -08:00
Kyle Meyer 893dbf5ba1 rename_ref: replace empty message in HEAD's log
When the current branch is renamed, the deletion of the old ref is
recorded in HEAD's log with an empty message.  Now that delete_ref()
accepts a reflog message, provide a more descriptive message by
passing along the log message that is given to rename_ref().

The next step will be to extend HEAD's log to also include the second
part of the rename, the creation of the new branch.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-20 22:04:47 -08:00
Kyle Meyer 755b49ae96 delete_ref: accept a reflog message argument
When the current branch is renamed with 'git branch -m/-M' or deleted
with 'git update-ref -m<msg> -d', the event is recorded in HEAD's log
with an empty message.  In preparation for adding a more meaningful
message to HEAD's log in these cases, update delete_ref() to take a
message argument and pass it along to ref_transaction_delete().
Modify all callers to pass NULL for the new message argument; no
change in behavior is intended.

Note that this is relevant for HEAD's log but not for the deleted
ref's log, which is currently deleted along with the ref.  Even if it
were not, an entry for the deletion wouldn't be present in the deleted
ref's log.  files_transaction_commit() writes to the log if
REF_NEEDS_COMMIT or REF_LOG_ONLY are set, but lock_ref_for_update()
doesn't set REF_NEEDS_COMMIT for the deleted ref because REF_DELETING
is set.  In contrast, the update for HEAD has REF_LOG_ONLY set by
split_head_update(), resulting in the deletion being logged.

Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-20 22:04:47 -08:00
Michael Haggerty 3c0cb0cbae read_loose_refs(): read refs using resolve_ref_recursively()
There is no need to call read_ref_full() or resolve_gitlink_ref() from
read_loose_refs(), because we already have a ref_store object in hand.
So we can call resolve_ref_recursively() ourselves. Happily, this
unifies the code for the submodule vs. non-submodule cases.

This requires resolve_ref_recursively() to be exposed to the refs
subsystem, though not to non-refs code.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-13 15:14:15 -08:00
Michael Haggerty 9c7d772b6b files_ref_store::submodule: use NULL for the main repository
The old practice of storing the empty string in this member for the main
repository was a holdover from before 00eebe3 (refs: create a base class
"ref_store" for files_ref_store, 2016-09-04), when the submodule was
stored in a flex array at the end of `struct files_ref_store`. Storing
NULL for this case is more idiomatic and a tiny bit less code.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-10 11:13:26 -08:00
Michael Haggerty fbfd0a2915 base_ref_store_init(): remove submodule argument
This is another step towards weakening the 1:1 relationship between
ref_stores and submodules.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-10 11:13:26 -08:00
Michael Haggerty 32c597e7b2 refs: push the submodule attribute down
Push the submodule attribute down from ref_store to files_ref_store.
This is another step towards loosening the 1:1 connection between
ref_stores and submodules.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-10 11:13:26 -08:00
Junio C Hamano fafca0f72a Merge branch 'cw/log-updates-for-all-refs-really'
The "core.logAllRefUpdates" that used to be boolean has been
enhanced to take 'always' as well, to record ref updates to refs
other than the ones that are expected to be updated (i.e. branches,
remote-tracking branches and notes).

* cw/log-updates-for-all-refs-really:
  doc: add note about ignoring '--no-create-reflog'
  update-ref: add test cases for bare repository
  refs: add option core.logAllRefUpdates = always
  config: add markup to core.logAllRefUpdates doc
2017-02-03 11:25:19 -08:00
Cornelius Weig 341fb28621 refs: add option core.logAllRefUpdates = always
When core.logallrefupdates is true, we only create a new reflog for refs
that are under certain well-known hierarchies. The reason is that we
know that some hierarchies (like refs/tags) are not meant to change, and
that unknown hierarchies might not want reflogs at all (e.g., a
hypothetical refs/foo might be meant to change often and drop old
history immediately).

However, sometimes it is useful to override this decision and simply log
for all refs, because the safety and audit trail is more important than
the performance implications of keeping the log around.

This patch introduces a new "always" mode for the core.logallrefupdates
option which will log updates to everything under refs/, regardless
where in the hierarchy it is (we still will not log things like
ORIG_HEAD and FETCH_HEAD, which are known to be transient).

Based-on-patch-by: Jeff King <peff@peff.net>
Signed-off-by: Cornelius Weig <cornelius.weig@tngtech.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-31 10:01:24 -08:00
René Scharfe 8694769f3c use oidcpy() for copying hashes between instances of struct object_id
Patch generated by Coccinelle and contrib/coccinelle/object_id.cocci.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-30 14:23:42 -08:00
Michael Haggerty 446397774a files_transaction_commit(): clean up empty directories
When deleting/pruning references, remove any directories that are made
empty by the deletion of loose references or of reflogs. Otherwise such
empty directories can survive forever and accumulate over time. (Even
'pack-refs', which is smart enough to remove the parent directories of
loose references that it prunes, leaves directories that were already
empty.)

And now that files_transaction_commit() takes care of deleting the
parent directories of loose references that it prunes, we don't have to
do that in prune_ref() anymore.

This change would be unwise if the *creation* of these directories could
race with our deletion of them. But the earlier changes in this patch
series made the creation paths robust against races, so now it is safe
to tidy them up more aggressively.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty a8f0db2d99 try_remove_empty_parents(): teach to remove parents of reflogs, too
Add a new "flags" parameter that tells the function whether to remove
empty parent directories of the loose reference file, of the reflog
file, or both. The new functionality is not yet used.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 8bdaecb402 try_remove_empty_parents(): don't trash argument contents
It's bad manners and surprising and therefore error-prone.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 730e034286 try_remove_empty_parents(): rename parameter "name" -> "refname"
This is the standard nomenclature.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty ce0af24de0 delete_ref_loose(): inline function
It was hardly doing anything anymore, and had only one caller.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 0e81d016f1 delete_ref_loose(): derive loose reference path from lock
It is simpler to derive the path to the file that must be deleted from
"lock->ref_name" than from the lock_file object.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty fc31955294 log_ref_write_1(): inline function
Now files_log_ref_write() doesn't do anything beyond call
log_ref_write_1(), so inline the latter into the former.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 4533e5343b log_ref_setup(): manage the name of the reflog file internally
Instead of writing the name of the reflog file into a strbuf that is
supplied by the caller but not needed there, write it into a local
temporary buffer and remove the strbuf parameter entirely.

And while we're adjusting the function signature, reorder the arguments
to move the input parameters before the output parameters.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 87b21e05ed log_ref_write_1(): don't depend on logfile argument
It's unnecessary to pass a strbuf holding the reflog path up and down
the call stack now that it is hardly needed by the callers. Remove the
places where log_ref_write_1() uses it, in preparation for making it
internal to log_ref_setup().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty e404f459fd log_ref_setup(): pass the open file descriptor back to the caller
This function will most often be called by log_ref_write_1(), which
wants to append to the reflog file. In that case, it is silly to close
the file only for the caller to reopen it immediately. So, in the case
that the file was opened, pass the open file descriptor back to the
caller.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 1fb0c80985 log_ref_setup(): improve robustness against races
Change log_ref_setup() to use raceproof_create_file() to create the new
logfile. This makes it more robust against a race against another
process that might be trying to clean up empty directories while we are
trying to create a new logfile.

This also means that it will only call create_leading_directories() if
open() fails, which should be a net win. Even in the cases where we are
willing to create a new logfile, it will usually be the case that the
logfile already exists, or if not then that the directory containing the
logfile already exists. In such cases, we will save some work that was
previously done unconditionally.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 854bda6b4f log_ref_setup(): separate code for create vs non-create
The behavior of this function (especially how it handles errors) is
quite different depending on whether we are willing to create the reflog
vs. whether we are only trying to open an existing reflog. So separate
the code paths.

This also simplifies the next steps.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 81b1b6d4ff log_ref_write(): inline function
This function doesn't do anything beyond call files_log_ref_write(), so
replace it with the latter at its call sites.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 990c98d2bd rename_tmp_log(): improve error reporting
* Don't capitalize error strings
* Report true paths of affected files

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 6a7f363170 rename_tmp_log(): use raceproof_create_file()
Besides shortening the code, this saves an unnecessary call to
safe_create_leading_directories_const() in almost all cases.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 3b5d3c9848 lock_ref_sha1_basic(): use raceproof_create_file()
Instead of coding the retry loop inline, use raceproof_create_file() to
make lock acquisition safe against directory creation/deletion races.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty e5007a6820 lock_ref_sha1_basic(): inline constant
`lflags` is set a single time then never changed, so just inline it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:09 -08:00
Michael Haggerty 583643248a files_rename_ref(): tidy up whitespace
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-07 19:30:08 -08:00
Junio C Hamano f7300cbfdd Merge branch 'jk/ref-symlink-loop'
A stray symbolic link in $GIT_DIR/refs/ directory could make name
resolution loop forever, which has been corrected.

* jk/ref-symlink-loop:
  files_read_raw_ref: prevent infinite retry loops in general
  files_read_raw_ref: avoid infinite loop on broken symlinks
2016-10-17 13:25:20 -07:00
Jeff King e8c42cb9ce files_read_raw_ref: prevent infinite retry loops in general
Limit the number of retries to 3. That should be adequate to
prevent any races, while preventing the possibility of
infinite loops if the logic fails to handle any other
possible error modes correctly.

After the fix in the previous commit, there's no known way
to trigger an infinite loop, but I did manually verify that
this fixes the test in that commit even when the code change
is not applied.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-10 10:53:33 -07:00
Jeff King 3f7bd767ed files_read_raw_ref: avoid infinite loop on broken symlinks
Our ref resolution first runs lstat() on any path we try to
look up, because we want to treat symlinks specially (by
resolving them manually and considering them symrefs). But
if the results of `readlink` do _not_ look like a ref, we
fall through to treating it like a normal file, and just
read the contents of the linked path.

Since fcb7c76 (resolve_ref_unsafe(): close race condition
reading loose refs, 2013-06-19), that "normal file" code
path will stat() the file and if we see ENOENT, will jump
back to the lstat(), thinking we've seen inconsistent
results between the two calls. But for a symbolic ref, this
isn't a race: the lstat() found the symlink, and the stat()
is looking at the path it points to. We end up in an
infinite loop calling lstat() and stat().

We can fix this by avoiding the retry-on-inconsistent jump
when we know that we found a symlink. While we're at it,
let's add a comment explaining why the symlink case gets to
this code in the first place; without that, it is not
obvious that the correct solution isn't to avoid the stat()
code path entirely.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-10 10:53:16 -07:00
René Scharfe 9ed0d8d6e6 use QSORT
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code
base, replacing calls of qsort(3) with QSORT.  The resulting code is
shorter and supports empty arrays with NULL pointers.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-29 15:42:18 -07:00
Junio C Hamano 4322f3848a Merge branch 'mh/ref-store'
The ref-store abstraction was introduced to the refs API so that we
can plug in different backends to store references.

* mh/ref-store: (38 commits)
  refs: implement iteration over only per-worktree refs
  refs: make lock generic
  refs: add method to rename refs
  refs: add methods to init refs db
  refs: make delete_refs() virtual
  refs: add method for initial ref transaction commit
  refs: add methods for reflog
  refs: add method iterator_begin
  files_ref_iterator_begin(): take a ref_store argument
  split_symref_update(): add a files_ref_store argument
  lock_ref_sha1_basic(): add a files_ref_store argument
  lock_ref_for_update(): add a files_ref_store argument
  commit_ref_update(): add a files_ref_store argument
  lock_raw_ref(): add a files_ref_store argument
  repack_without_refs(): add a files_ref_store argument
  refs: make peel_ref() virtual
  refs: make create_symref() virtual
  refs: make pack_refs() virtual
  refs: make verify_refname_available() virtual
  refs: make read_raw_ref() virtual
  ...
2016-09-19 13:47:19 -07:00
David Turner 0c09ec07d1 refs: implement iteration over only per-worktree refs
Alternate refs backends might still use files to store per-worktree
refs. So provide a way to iterate over only the per-worktree references
in a ref_store. The other backend can set up a files ref_store and
iterate using the new DO_FOR_EACH_PER_WORKTREE_ONLY flag when iterating.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
David Turner 7d61826439 refs: make lock generic
Instead of including a files-backend-specific struct ref_lock, change
the generic ref_update struct to include a void pointer that backends
can use for their own arbitrary data.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
David Turner 9b6b40d93a refs: add method to rename refs
This removes the last caller of function get_files_ref_store(), so
remove it.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
David Turner 6fb5acfd8f refs: add methods to init refs db
Alternate refs backends might not need the refs/heads directory and so
on, so we make ref db initialization part of the backend.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
David Turner a27dcf89b6 refs: make delete_refs() virtual
In the file-based backend, delete_refs has some special optimization
to deal with packed refs.  In other backends, we might be able to make
ref deletion faster by putting all deletions into a single
transaction.  So we need a special backend function for this.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
David Turner fc6814637d refs: add method for initial ref transaction commit
Signed-off-by: Ronnie Sahlberg <rsahlberg@google.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:14 -07:00
David Turner e3688bd6cf refs: add methods for reflog
In the file-based backend, the reflog piggybacks on the ref lock.
Since other backends won't have the same sort of ref lock, ref backends
must also handle reflogs.

Signed-off-by: Ronnie Sahlberg <rsahlberg@google.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 1a769003c1 refs: add method iterator_begin
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 37b6f6d5f4 files_ref_iterator_begin(): take a ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty fcc42ea0c9 split_symref_update(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 7eb27cdfe6 lock_ref_sha1_basic(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty b3bbbc5c24 lock_ref_for_update(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty f18a789250 commit_ref_update(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty f7b0a987b5 lock_raw_ref(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 0a95ac5f63 repack_without_refs(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty bd427cf27f refs: make peel_ref() virtual
For now it only supports the main reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 284689ba0f refs: make create_symref() virtual
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 8231527e15 refs: make pack_refs() virtual
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 62665823d2 refs: make verify_refname_available() virtual
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty e1e33b722c refs: make read_raw_ref() virtual
Reference backends will be able to customize this function to implement
reference reading.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 424dcc7683 resolve_gitlink_ref(): implement using resolve_ref_recursively()
resolve_ref_recursively() can handle references in arbitrary files
reference stores, so use it to resolve "gitlink" (i.e., submodule)
references. Aside from removing redundant code, this allows submodule
lookups to benefit from the much more robust code that we use for
reading non-submodule references. And, since the code is now agnostic
about reference backends, it will work for any future references
backend (so move its definition to refs.c).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:13 -07:00
Michael Haggerty 34c7ad8ffc read_raw_ref(): take a (struct ref_store *) argument
And make the function work for submodules.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty b9180c9d5d resolve_gitlink_packed_ref(): remove function
Now that resolve_packed_ref() can work with an arbitrary
files_ref_store, there is no need to have a separate
resolve_gitlink_packed_ref() function.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty 611118d06e resolve_packed_ref(): rename function from resolve_missing_loose_ref()
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty 6356c658e4 refs: reorder definitions
Move resolve_gitlink_ref() and related functions lower in the file to
avoid the need for forward declarations in the next step.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Ronnie Sahlberg 127b42a186 refs: add a transaction_commit() method
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty 49c0df6a68 {lock,commit,rollback}_packed_refs(): add files_ref_store arguments
These functions currently only work in the main repository, so add an
assert_main_repository() check to each function.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty 4308651c3c resolve_missing_loose_ref(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty f0d21efc35 get_packed_ref(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty d99825ab73 add_packed_ref(): add a files_ref_store argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty 00eebe351c refs: create a base class "ref_store" for files_ref_store
We want ref_stores to be polymorphic, so invent a base class of which
files_ref_store is a derived class. For now there is exactly one
ref_store for the main repository and one for any submodules whose
references have been accessed.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Ronnie Sahlberg 3dce444f17 refs: add a backend method structure
Add a `struct ref_storage_be` to represent types of reference stores. In
OO notation, this is the class, and will soon hold some class
methods (e.g., a factory to create new ref_store instances) and will
also serve as the vtable for ref_store instances of that type.

As yet, the backends cannot do anything.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty 65a0a8e5fa refs: rename struct ref_cache to files_ref_store
The greater goal of this patch series is to develop the concept of a
reference store, which is a place that references, their values, and
their reflogs are stored, and to virtualize the reference interface so
that different types of ref_stores can be implemented. We will then, for
example, use ref_store instances to access submodule references and
worktree references.

Currently, we keep a ref_cache for each submodule that has had its
references iterated over. It is a far cry from a ref_store, but they are
stored the way we will want to store ref_stores, and ref_stores will
eventually have to hold the reference caches. So let's treat ref_caches
as embryo ref_stores, and build them out from there.

As the first step, simply rename `ref_cache` to `files_ref_store`, and
rename some functions and attributes correspondingly.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Michael Haggerty f6e75467ca resolve_gitlink_ref(): eliminate temporary variable
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-09 15:28:12 -07:00
Jacob Keller 99b43a61f2 allow do_submodule_path to work even if submodule isn't checked out
Currently, do_submodule_path will attempt locating the .git directory by
using read_gitfile on <path>/.git. If this fails it just assumes the
<path>/.git is actually a git directory.

This is good because it allows for handling submodules which were cloned
in a regular manner first before being added to the superproject.

Unfortunately this fails if the <path> is not actually checked out any
longer, such as by removing the directory.

Fix this by checking if the directory we found is actually a gitdir. In
the case it is not, attempt to lookup the submodule configuration and
find the name of where it is stored in the .git/modules/ directory of
the superproject.

If we can't locate the submodule configuration, this might occur because
for example a submodule gitlink was added but the corresponding
.gitmodules file was not properly updated.  A die() here would not be
pleasant to the users of submodule diff formats, so instead, modify
do_submodule_path() to return an error code:

 - git_pathdup_submodule() returns NULL when we fail to find a path.
 - strbuf_git_path_submodule() propagates the error code to the caller.

Modify the callers of these functions to check the error code and fail
properly. This ensures we don't attempt to use a bad path that doesn't
match the corresponding submodule.

Because this change fixes add_submodule_odb() to work even if the
submodule is not checked out, update the wording of the submodule log
diff format to correctly display that the submodule is "not initialized"
instead of "not checked out"

Add tests to ensure this change works as expected.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-08-31 18:07:10 -07:00
Junio C Hamano 87492cb24d Merge branch 'mh/ref-iterators'
The API to iterate over all the refs (i.e. for_each_ref(), etc.)
has been revamped.

* mh/ref-iterators:
  for_each_reflog(): reimplement using iterators
  dir_iterator: new API for iterating over a directory tree
  for_each_reflog(): don't abort for bad references
  do_for_each_ref(): reimplement using reference iteration
  refs: introduce an iterator interface
  ref_resolves_to_object(): new function
  entry_resolves_to_object(): rename function from ref_resolves_to_object()
  get_ref_cache(): only create an instance if there is a submodule
  remote rm: handle symbolic refs correctly
  delete_refs(): add a flags argument
  refs: use name "prefix" consistently
  do_for_each_ref(): move docstring to the header file
  refs: remove unnecessary "extern" keywords
2016-07-25 14:13:33 -07:00
Junio C Hamano 702ebbf4e2 Merge branch 'mh/update-ref-errors'
Error handling in the codepaths that updates refs has been
improved.

* mh/update-ref-errors:
  lock_ref_for_update(): avoid a symref resolution
  lock_ref_for_update(): make error handling more uniform
  t1404: add more tests of update-ref error handling
  t1404: document function test_update_rejected
  t1404: remove "prefix" argument to test_update_rejected
  t1404: rename file to t1404-update-ref-errors.sh
2016-07-25 14:13:33 -07:00
Junio C Hamano 6b34ce90a7 Merge branch 'mh/split-under-lock'
Further preparatory work on the refs API before the pluggable
backend series can land.

* mh/split-under-lock: (33 commits)
  lock_ref_sha1_basic(): only handle REF_NODEREF mode
  commit_ref_update(): remove the flags parameter
  lock_ref_for_update(): don't resolve symrefs
  lock_ref_for_update(): don't re-read non-symbolic references
  refs: resolve symbolic refs first
  ref_transaction_update(): check refname_is_safe() at a minimum
  unlock_ref(): move definition higher in the file
  lock_ref_for_update(): new function
  add_update(): initialize the whole ref_update
  verify_refname_available(): adjust constness in declaration
  refs: don't dereference on rename
  refs: allow log-only updates
  delete_branches(): use resolve_refdup()
  ref_transaction_commit(): correctly report close_ref() failure
  ref_transaction_create(): disallow recursive pruning
  refs: make error messages more consistent
  lock_ref_sha1_basic(): remove unneeded local variable
  read_raw_ref(): move docstring to header file
  read_raw_ref(): improve docstring
  read_raw_ref(): rename symref argument to referent
  ...
2016-07-25 14:13:32 -07:00
brian m. carlson c368dde924 coccinelle: apply object_id Coccinelle transformations
Apply the set of semantic patches from contrib/coccinelle to convert
some leftover places using struct object_id's hash member to instead
use the wrapper functions that take struct object_id natively.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-28 11:39:02 -07:00
Michael Haggerty 841caad903 lock_ref_for_update(): avoid a symref resolution
If we're overwriting a symref with a SHA-1, we need to resolve the value
of the symref (1) to check against update->old_sha1 and (2) to write to
its reflog. However, we've already read the symref itself and know its
referent. So there is no need to read the symref's value through the
symref; we can read the referent directly.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:49:00 -07:00
Michael Haggerty e3f510393c lock_ref_for_update(): make error handling more uniform
To aid the effort, extract a new function, check_old_oid(), and use it
in the two places where the read value of the reference has to be
checked against update->old_sha1.

Update tests to reflect the improvements.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:49:00 -07:00
Michael Haggerty 2880d16f09 for_each_reflog(): reimplement using iterators
Allow references with reflogs to be iterated over using a ref_iterator.
The latter is implemented as a files_reflog_iterator, which in turn uses
dir_iterator to read the "logs" directory.

Note that reflog iteration doesn't correctly handle per-worktree
reflogs (either before or after this patch).

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:21 -07:00
Michael Haggerty d24b21e9fc for_each_reflog(): don't abort for bad references
If there is a file under "$GIT_DIR/logs" with no corresponding
reference, the old code was emitting an error message, aborting the
reflog iteration, and returning -1. But

* None of the callers was checking the exit value

* The callers all want to find all legitimate reflogs (sometimes for the
  purpose of determining object reachability!) and wouldn't benefit from
  a truncated iteration anyway.

So instead, emit an error message and skip the "broken" reflog, but
continue with the iteration.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:20 -07:00
Michael Haggerty 4c4de89573 do_for_each_ref(): reimplement using reference iteration
Use the reference iterator interface to implement do_for_each_ref().
Delete a bunch of code supporting the old for_each_ref() implementation.
And now that do_for_each_ref() is generic code (it is no longer tied to
the files backend), move it to refs.c.

The implementation is via a new function, do_for_each_ref_iterator(),
which takes a reference iterator as argument and calls a callback
function for each of the references in the iterator.

This change requires the current_ref performance hack for peel_ref() to
be implemented via ref_iterator_peel() rather than peel_entry() because
we don't have a ref_entry handy (it is hidden under three layers:
file_ref_iterator, merge_ref_iterator, and cache_ref_iterator). So:

* do_for_each_ref_iterator() records the active iterator in
  current_ref_iter while it is running.

* peel_ref() checks whether current_ref_iter is pointing at the
  requested reference. If so, it asks the iterator to peel the
  reference (which it can do efficiently via its "peel" virtual
  function). For extra safety, we do the optimization only if the
  refname *addresses* are the same, not only if the refname *strings*
  are the same, to forestall possible mixups between refnames that come
  from different ref_iterators.

Please note that this optimization of peel_ref() is only available when
iterating via do_for_each_ref_iterator() (including all of the
for_each_ref() functions, which call it indirectly). It would be
complicated to implement a similar optimization when iterating directly
using a reference iterator, because multiple reference iterators can be
in use at the same time, with interleaved calls to
ref_iterator_advance(). (In fact we do exactly that in
merge_ref_iterator.)

But that is not necessary. peel_ref() is only called while iterating
over references. Callers who iterate using the for_each_ref() functions
benefit from the optimization described above. Callers who iterate using
reference iterators directly have access to the ref_iterator, so they
can call ref_iterator_peel() themselves to get an analogous optimization
in a more straightforward manner.

If we rewrite all callers to use the reference iteration API, then we
can remove the current_ref_iter hack permanently.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:20 -07:00
Michael Haggerty 3bc581b940 refs: introduce an iterator interface
Currently, the API for iterating over references is via a family of
for_each_ref()-type functions that invoke a callback function for each
selected reference. All of these eventually call do_for_each_ref(),
which knows how to do one thing: iterate in parallel through two
ref_caches, one for loose and one for packed refs, giving loose
references precedence over packed refs. This is rather complicated code,
and is quite specialized to the files backend. It also requires callers
to encapsulate their work into a callback function, which often means
that they have to define and use a "cb_data" struct to manage their
context.

The current design is already bursting at the seams, and will become
even more awkward in the upcoming world of multiple reference storage
backends:

* Per-worktree vs. shared references are currently handled via a kludge
  in git_path() rather than iterating over each part of the reference
  namespace separately and merging the results. This kludge will cease
  to work when we have multiple reference storage backends.

* The current scheme is inflexible. What if we sometimes want to bypass
  the ref_cache, or use it only for packed or only for loose refs? What
  if we want to store symbolic refs in one type of storage backend and
  non-symbolic ones in another?

In the future, each reference backend will need to define its own way of
iterating over references. The crux of the problem with the current
design is that it is impossible to compose for_each_ref()-style
iterations, because the flow of control is owned by the for_each_ref()
function. There is nothing that a caller can do but iterate through all
references in a single burst, so there is no way for it to interleave
references from multiple backends and present the result to the rest of
the world as a single compound backend.

This commit introduces a new iteration primitive for references: a
ref_iterator. A ref_iterator is a polymorphic object that a reference
storage backend can be asked to instantiate. There are three functions
that can be applied to a ref_iterator:

* ref_iterator_advance(): move to the next reference in the iteration
* ref_iterator_abort(): end the iteration before it is exhausted
* ref_iterator_peel(): peel the reference currently being looked at

Iterating using a ref_iterator leaves the flow of control in the hands
of the caller, which means that ref_iterators from multiple
sources (e.g., loose and packed refs) can be composed and presented to
the world as a single compound ref_iterator.

It also means that the backend code for implementing reference iteration
will sometimes be more complicated. For example, the
cache_ref_iterator (which iterates over a ref_cache) can't use the C
stack to recurse; instead, it must manage its own stack internally as
explicit data structures. There is also a lot of boilerplate connected
with object-oriented programming in C.

Eventually, end-user callers will be able to be written in a more
natural way—managing their own flow of control rather than having to
work via callbacks. Since there will only be a few reference backends
but there are many consumers of this API, this is a good tradeoff.

More importantly, we gain composability, and especially the possibility
of writing interchangeable parts that can work with any ref_iterator.

For example, merge_ref_iterator implements a generic way of merging the
contents of any two ref_iterators. It is used to merge loose + packed
refs as part of the implementation of the files_ref_iterator. But it
will also be possible to use it to merge other pairs of reference
sources (e.g., per-worktree vs. shared refs).

Another example is prefix_ref_iterator, which can be used to trim a
prefix off the front of reference names before presenting them to the
caller (e.g., "refs/heads/master" -> "master").

In this patch, we introduce the iterator abstraction and many utilities,
and implement a reference iterator for the files ref storage backend.
(I've written several other obvious utilities, for example a generic way
to filter references being iterated over. These will probably be useful
in the future. But they are not needed for this patch series, so I am
not including them at this time.)

In a moment we will rewrite do_for_each_ref() to work via reference
iterators (allowing some special-purpose code to be discarded), and do
something similar for reflogs. In future patch series, we will expose
the ref_iterator abstraction in the public refs API so that callers can
use it directly.

Implementation note: I tried abstracting this a layer further to allow
generic iterators (over arbitrary types of objects) and generic
utilities like a generic merge_iterator. But the implementation in C was
very cumbersome, involving (in my opinion) too much boilerplate and too
much unsafe casting, some of which would have had to be done on the
caller side. However, I did put a few iterator-related constants in a
top-level header file, iterator.h, as they will be useful in a moment to
implement iteration over directory trees and possibly other types of
iterators in the future.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:20 -07:00
Michael Haggerty a873924483 ref_resolves_to_object(): new function
Extract new function ref_resolves_to_object() from
entry_resolves_to_object(). It can be used even if there is no ref_entry
at hand.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:19 -07:00
Michael Haggerty ffeef64231 entry_resolves_to_object(): rename function from ref_resolves_to_object()
Free up the old name for a more general purpose.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:19 -07:00
Michael Haggerty 2eed2780f0 get_ref_cache(): only create an instance if there is a submodule
If there is not a nonbare repository where a submodule is supposedly
located, then don't instantiate a ref_cache for it.

The analogous check can be removed from resolve_gitlink_ref().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:19 -07:00
Michael Haggerty c5f04dddb6 delete_refs(): add a flags argument
This will be useful for passing REF_NODEREF through.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:18 -07:00
Michael Haggerty 4633a846f5 refs: use name "prefix" consistently
In the context of the for_each_ref() functions, call the prefix that
references must start with "prefix". (In some places it was called
"base".) This is clearer, and also prevents confusion with another
planned use of the word "base".

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:18 -07:00
Michael Haggerty 067622b0e8 do_for_each_ref(): move docstring to the header file
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:17 -07:00
Michael Haggerty 7a418f3a17 lock_ref_sha1_basic(): only handle REF_NODEREF mode
Now lock_ref_sha1_basic() is only called with flags==REF_NODEREF. So we
don't have to handle other cases anymore.

This enables several simplifications, the most interesting of which come
from the fact that ref_lock::orig_ref_name is now always the same as
ref_lock::ref_name:

* Remove ref_lock::orig_ref_name
* Remove local variable orig_refname from lock_ref_sha1_basic()
* ref_name can be initialize once and its value reused
* commit_ref_update() never has to write to the reflog for
  lock->orig_ref_name

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:50 +02:00
Michael Haggerty 5d9b2de4ef commit_ref_update(): remove the flags parameter
commit_ref_update() is now only called with flags=0. So remove the flags
parameter entirely.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:50 +02:00
Michael Haggerty 6e30b2f652 lock_ref_for_update(): don't resolve symrefs
If a transaction includes a non-NODEREF update to a symbolic reference,
we don't have to look it up in lock_ref_for_update(). The reference will
be dereferenced anyway when the split-off update is processed.

This change requires that we store a backpointer from the split-off
update to its parent update, for two reasons:

* We still want to report the original reference name in error messages.
  So if an error occurs when checking the split-off update's old_sha1,
  walk the parent_update pointers back to find the original reference
  name, and report that one.

* We still need to write the old_sha1 of the symref to its reflog. So
  after we read the split-off update's reference value, walk the
  parent_update pointers back and fill in their old_sha1 fields.

Aside from eliminating unnecessary reads, this change fixes a
subtle (though not very serious) race condition: in the old code, the
old_sha1 of the symref was resolved before the reference that it pointed
at was locked. So it was possible that the old_sha1 value logged to the
symref's reflog could be wrong if another process changed the downstream
reference before it was locked.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:50 +02:00
Michael Haggerty 8169d0d06a lock_ref_for_update(): don't re-read non-symbolic references
Before the previous patch, our first read of the reference happened
before the reference was locked, so we couldn't trust its value and had
to read it again. But now that our first read of the reference happens
after acquiring the lock, there is no need to read it a second time. So
move the read_ref_full() call into the (update->type & REF_ISSYMREF)
block.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:50 +02:00
Michael Haggerty 92b1551b1d refs: resolve symbolic refs first
Before committing ref updates, split symbolic ref updates into two
parts: an update to the underlying ref, and a log-only update to the
symbolic ref. This ensures that both references are locked correctly
during the transaction, including while their reflogs are updated.

Similarly, if the reference pointed to by HEAD is modified directly, add
a separate log-only update to HEAD, rather than leaving the job of
updating HEAD's reflog to commit_ref_update(). This change ensures that
HEAD is locked correctly while its reflog is being modified, as well as
being cheaper (HEAD only needs to be resolved once).

This makes use of a new function, lock_raw_ref(), which is analogous to
read_raw_ref(), but acquires a lock on the reference before reading it.

This change still has two problems:

* There are redundant read_ref_full() reference lookups.

* It is still possible to get incorrect reflogs for symbolic references
  if there is a concurrent update by another process, since the old_oid
  of a symref is determined before the lock on the pointed-to ref is
  held.

Both problems will soon be fixed.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>

WIP
2016-06-13 11:23:50 +02:00
Michael Haggerty 8415d24746 unlock_ref(): move definition higher in the file
This avoids the need for a forward declaration in the next patch.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty 165056b2fc lock_ref_for_update(): new function
Extract a new function, lock_ref_for_update(), from
ref_transaction_commit().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty 3a8af7be8f verify_refname_available(): adjust constness in declaration
The two string_list arguments can be const.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
David Turner 12fd3496d1 refs: don't dereference on rename
When renaming refs, don't dereference either the origin or the destination
before renaming.

The origin does not need to be dereferenced because it is presently
forbidden to rename symbolic refs.

Not dereferencing the destination fixes a bug where renaming on top of
a broken symref would use the pointed-to ref name for the moved
reflog.

Add a test for the reflog bug.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
David Turner d99aa884df refs: allow log-only updates
The refs infrastructure learns about log-only ref updates, which only
update the reflog.  Later, we will use this to separate symbolic
reference resolution from ref updating.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty 5a563d4ad1 ref_transaction_commit(): correctly report close_ref() failure
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty c52ce248d6 ref_transaction_create(): disallow recursive pruning
It is nonsensical (and a little bit dangerous) to use REF_ISPRUNING
without REF_NODEREF. Forbid it explicitly. Change the one REF_ISPRUNING
caller to pass REF_NODEREF too.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty 0568c8e9dc refs: make error messages more consistent
* Always start error messages with a lower-case letter.

* Always enclose reference names in single quotes.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty bcb497d0f8 lock_ref_sha1_basic(): remove unneeded local variable
resolve_ref_unsafe() can cope with being called with NULL passed to its
flags argument. So lock_ref_sha1_basic() can just hand its own type
parameter through.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty cf596442c6 read_raw_ref(): move docstring to header file
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty bb462b0028 read_raw_ref(): improve docstring
Among other things, document the (important!) requirement that input
refname be checked for safety before calling this function.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty 92b380931e read_raw_ref(): rename symref argument to referent
After all, it doesn't hold the symbolic reference, but rather the
reference referred to.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty fa96ea1b88 read_raw_ref(): clear *type at start of function
This is more convenient and less error-prone for callers.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty 3a0b6b9aba read_raw_ref(): rename flags argument to type
This will hopefully reduce confusion with the "flags" arguments that are
used in many functions in this module as an input parameter to choose
how the function should operate.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:49 +02:00
Michael Haggerty efe472813d ref_transaction_commit(): remove local variables n and updates
These microoptimizations don't make a significant difference in speed.
And they cause problems if somebody ever wants to modify the function to
add updates to a transaction as part of processing it, as will happen
shortly.

Make the same changes in initial_ref_transaction_commit().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-06-13 11:23:26 +02:00
Michael Haggerty e711b1af2e rename_ref(): remove unneeded local variable
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-05-05 16:37:30 +02:00
Michael Haggerty 76fc394d50 commit_ref_update(): write error message to *err, not stderr
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-05-05 16:37:30 +02:00
Michael Haggerty e167a5673e read_raw_ref(): don't get confused by an empty directory
Even if there is an empty directory where we look for the loose version
of a reference, check for a packed reference before giving up. This
fixes the failing test that was introduced two commits ago.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-05-05 16:37:04 +02:00
Michael Haggerty 5387c0d883 commit_ref(): if there is an empty dir in the way, delete it
Part of the bug revealed in the last commit is that resolve_ref_unsafe()
incorrectly returns EISDIR if it finds a directory in the place where it
is looking for a loose reference, even if the corresponding packed
reference exists. lock_ref_sha1_basic() notices the bogus EISDIR, and
use it as an indication that it should call remove_empty_directories()
and call resolve_ref_unsafe() again.

But resolve_ref_unsafe() shouldn't report EISDIR in this case. If we
would simply make that change, then remove_empty_directories() wouldn't
get called anymore, and the empty directory would get in the way when
commit_ref() calls commit_lock_file() to rename the lockfile into place.

So instead of relying on lock_ref_sha1_basic() to delete empty
directories, teach commit_ref(), just before calling commit_lock_file(),
to check whether a directory is in the way, and if so, try to delete it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
2016-05-05 16:31:17 +02:00
Junio C Hamano edc2f715bd Merge branch 'dt/pre-refs-backend'
Code restructuring around the "refs" area to prepare for pluggable
refs backends.

* dt/pre-refs-backend: (24 commits)
  refs: on symref reflog expire, lock symref not referrent
  refs: move resolve_ref_unsafe into common code
  show_head_ref(): check the result of resolve_ref_namespace()
  check_aliased_update(): check that dst_name is non-NULL
  checkout_paths(): remove unneeded flag variable
  cmd_merge(): remove unneeded flag variable
  fsck_head_link(): remove unneeded flag variable
  read_raw_ref(): change flags parameter to unsigned int
  files-backend: inline resolve_ref_1() into resolve_ref_unsafe()
  read_raw_ref(): manage own scratch space
  files-backend: break out ref reading
  resolve_ref_1(): eliminate local variable "bad_name"
  resolve_ref_1(): reorder code
  resolve_ref_1(): eliminate local variable
  resolve_ref_unsafe(): ensure flags is always set
  resolve_ref_unsafe(): use for loop to count up to MAXDEPTH
  resolve_missing_loose_ref(): simplify semantics
  t1430: improve test coverage of deletion of badly-named refs
  t1430: test for-each-ref in the presence of badly-named refs
  t1430: don't rely on symbolic-ref for creating broken symrefs
  ...
2016-04-25 15:17:15 -07:00
David Turner 41d796ed5c refs: on symref reflog expire, lock symref not referrent
When locking a symbolic ref to expire a reflog, lock the symbolic
ref (using REF_NODEREF) instead of its referent.

Add a test for this.

Signed-off-by: David Turner <dturner@twopensource.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:46 -07:00
David Turner 2d0663b216 refs: move resolve_ref_unsafe into common code
Now that resolve_ref_unsafe's only interaction with the backend is
through read_raw_ref, we can move it into the common code. Later,
we'll replace read_raw_ref with a backend function.

Signed-off-by: David Turner <dturner@twopensource.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:41 -07:00
Michael Haggerty 89e8238965 read_raw_ref(): change flags parameter to unsigned int
read_raw_ref() is going to be part of the vtable for reference backends,
so clean up its interface to use "unsigned int flags" rather than "int
flags". Its caller still uses signed int for its flags arguments. But
changing that would touch a lot of code, so leave it for now.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:31 -07:00
Michael Haggerty 8c346fb1d7 files-backend: inline resolve_ref_1() into resolve_ref_unsafe()
resolve_ref_unsafe() wasn't doing anything useful anymore.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:29 -07:00
Michael Haggerty 42a38cf788 read_raw_ref(): manage own scratch space
Instead of creating scratch space in resolve_ref_unsafe() and passing
it down through resolve_ref_1 to read_raw_ref(), teach read_raw_ref()
to manage its own scratch space. This reduces coupling across the
functions at the cost of some extra allocations.

Also, when read_raw_ref() is implemented for different reference
backends, the other implementations might have different scratch
space requirements.

Note that we now preserve errno across the calls to strbuf_release(),
which calls free() and can thus theoretically overwrite errno.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:26 -07:00
David Turner 7048653a73 files-backend: break out ref reading
Refactor resolve_ref_1 in terms of a new function read_raw_ref, which
is responsible for reading ref data from the ref storage.

Later, we will make read_raw_ref a pluggable backend function, and make
resolve_ref_unsafe common.

Signed-off-by: David Turner <dturner@twopensource.com>
Helped-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:24 -07:00
Michael Haggerty afbe782fa3 resolve_ref_1(): eliminate local variable "bad_name"
We can use (*flags & REF_BAD_NAME) for that purpose.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:22 -07:00
Michael Haggerty e6702e570b resolve_ref_1(): reorder code
There is no need to adjust *flags if we're just about to fail.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:21 -07:00
Michael Haggerty 90c28ae11c resolve_ref_1(): eliminate local variable
In place of `buf`, use `refname`, which is anyway a better description
of what is being pointed at.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:19 -07:00
Michael Haggerty a70a93b794 resolve_ref_unsafe(): ensure flags is always set
If the caller passes flags==NULL, then set it to point at a local
scratch variable. This removes the need for a lot of "if (flags)"
guards in resolve_ref_1() and resolve_missing_loose_ref().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:17 -07:00
Michael Haggerty 37da4227b2 resolve_ref_unsafe(): use for loop to count up to MAXDEPTH
The loop's there anyway; we might as well use it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:15 -07:00
Michael Haggerty 419c6f4c76 resolve_missing_loose_ref(): simplify semantics
Make resolve_missing_loose_ref() only responsible for looking up a
packed reference, without worrying about whether we want to read or
write the reference and without setting errno on failure. Move the other
logic to the caller.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:35:13 -07:00
David Turner 937705901b refs: move for_each_*ref* functions into common code
Make do_for_each_ref take a submodule as an argument instead of a
ref_cache.  Since all for_each_*ref* functions are defined in terms of
do_for_each_ref, we can then move them into the common code.

Later, we can simply make do_for_each_ref into a backend function.

Signed-off-by: David Turner <dturner@twopensource.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:34:55 -07:00
David Turner 2bf68ed5aa refs: move head_ref{,_submodule} to the common code
These don't use any backend-specific functions.  These were previously
defined in terms of the do_head_ref helper function, but since they
are otherwise identical, we don't need that function.

Signed-off-by: David Turner <dturner@twopensource.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-10 11:34:41 -07:00
Kazuki Yamaguchi 18eb3a9ce7 set_worktree_head_symref(): fix error message
Emit an informative error when failed to hold lock of HEAD.

2233066e (refs: add a new function set_worktree_head_symref,
2016-03-27) added set_worktree_head_symref(), but this is missing a
call to unable_to_lock_message() after hold_lock_file_for_update()
fails, so it emits an empty error message:

  % git branch -m oldname newname
  error:
  error: HEAD of working tree /path/to/wt is not updated
  fatal: Branch renamed to newname, but HEAD is not updated!

Thanks to Eric Sunshine for pointing this out.

Signed-off-by: Kazuki Yamaguchi <k@rhe.jp>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-08 10:26:23 -07:00
Kazuki Yamaguchi 2233066e77 refs: add a new function set_worktree_head_symref
Add a new function set_worktree_head_symref, to update HEAD symref for
the specified worktree.

To update HEAD of a linked working tree,
create_symref("worktrees/$work_tree/HEAD", "refs/heads/$branch", msg)
could be used. However when it comes to updating HEAD of the main
working tree, it is unusable because it uses $GIT_DIR for
worktree-specific symrefs (HEAD).

The new function takes git_dir (real directory) as an argument, and
updates HEAD of the working tree. This function will be used when
renaming a branch.

Signed-off-by: Kazuki Yamaguchi <k@rhe.jp>
Acked-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-04 12:57:21 -07:00
Junio C Hamano 11529ecec9 Merge branch 'jk/tighten-alloc'
Update various codepaths to avoid manually-counted malloc().

* jk/tighten-alloc: (22 commits)
  ewah: convert to REALLOC_ARRAY, etc
  convert ewah/bitmap code to use xmalloc
  diff_populate_gitlink: use a strbuf
  transport_anonymize_url: use xstrfmt
  git-compat-util: drop mempcpy compat code
  sequencer: simplify memory allocation of get_message
  test-path-utils: fix normalize_path_copy output buffer size
  fetch-pack: simplify add_sought_entry
  fast-import: simplify allocation in start_packfile
  write_untracked_extension: use FLEX_ALLOC helper
  prepare_{git,shell}_cmd: use argv_array
  use st_add and st_mult for allocation size computation
  convert trivial cases to FLEX_ARRAY macros
  use xmallocz to avoid size arithmetic
  convert trivial cases to ALLOC_ARRAY
  convert manual allocations to argv_array
  argv-array: add detach function
  add helpers for allocating flex-array structs
  harden REALLOC_ARRAY and xcalloc against size_t overflow
  tree-diff: catch integer overflow in combine_diff_path allocation
  ...
2016-02-26 13:37:16 -08:00
Jeff King 96ffc06f72 convert trivial cases to FLEX_ARRAY macros
Using FLEX_ARRAY macros reduces the amount of manual
computation size we have to do. It also ensures we don't
overflow size_t, and it makes sure we write the same number
of bytes that we allocated.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00
Junio C Hamano ad25723e69 Merge branch 'jk/ref-cache-non-repository-optim'
The underlying machinery used by "ls-files -o" and other commands
have been taught not to create empty submodule ref cache for a
directory that is not a submodule.  This removes a ton of wasted
CPU cycles.

* jk/ref-cache-non-repository-optim:
  resolve_gitlink_ref: ignore non-repository paths
  clean: make is_git_repository a public function
2016-02-03 14:16:07 -08:00
Jeff King a2d5156c2b resolve_gitlink_ref: ignore non-repository paths
When we want to look up a submodule ref, we use
get_ref_cache(path) to find or auto-create its ref cache.
But if we feed a path that isn't actually a git repository,
we blindly create the ref cache, and then may die deeper in
the code when we try to access it. This is a problem because
many callers speculatively feed us a path that looks vaguely
like a repository, and expect us to tell them when it is
not.

This patch teaches resolve_gitlink_ref to reject
non-repository paths without creating a ref_cache. This
avoids the die(), and also performs better if you have a
large number of these faux-submodule directories (because
the ref_cache lookup is linear, under the assumption that
there won't be a large number of submodules).

To accomplish this, we also break get_ref_cache into two
pieces: the lookup and auto-creation (the latter is lumped
into create_ref_cache). This lets us first cheaply ask our
cache "is it a submodule we know about?" If so, we can avoid
repeating our filesystem lookup. So lookups of real
submodules are not penalized; they examine the submodule's
.git directory only once.

The test in t3000 demonstrates a case where this improves
correctness (we used to just die). The new perf case in
p7300 shows off the speed improvement in an admittedly
pathological repository:

Test                  HEAD^               HEAD
----------------------------------------------------------------
7300.4: ls-files -o   66.97(66.15+0.87)   0.33(0.08+0.24) -99.5%

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-25 11:42:13 -08:00
Jeff King 2859dcd4c8 lock_ref_sha1_basic: handle REF_NODEREF with invalid refs
We sometimes call lock_ref_sha1_basic with REF_NODEREF
to operate directly on a symbolic ref. This is used, for
example, to move to a detached HEAD, or when updating
the contents of HEAD via checkout or symbolic-ref.

However, the first step of the function is to resolve the
refname to get the "old" sha1, and we do so without telling
resolve_ref_unsafe() that we are only interested in the
symref. As a result, we may detect a problem there not with
the symref itself, but with something it points to.

The real-world example I found (and what is used in the test
suite) is a HEAD pointing to a ref that cannot exist,
because it would cause a directory/file conflict with other
existing refs.  This situation is somewhat broken, of
course, as trying to _commit_ on that HEAD would fail. But
it's not explicitly forbidden, and we should be able to move
away from it. However, neither "git checkout" nor "git
symbolic-ref" can do so. We try to take the lock on HEAD,
which is pointing to a non-existent ref. We bail from
resolve_ref_unsafe() with errno set to EISDIR, and the lock
code thinks we are attempting to create a d/f conflict.

Of course we're not. The problem is that the lock code has
no idea what level we were at when we got EISDIR, so trying
to diagnose or remove empty directories for HEAD is not
useful.

To make things even more complicated, we only get EISDIR in
the loose-ref case. If the refs are packed, the resolution
may "succeed", giving us the pointed-to ref in "refname",
but a null oid. Later, we say "ah, the null oid means we are
creating; let's make sure there is room for it", but
mistakenly check against the _resolved_ refname, not the
original.

We can fix this by making two tweaks:

  1. Call resolve_ref_unsafe() with RESOLVE_REF_NO_RECURSE
     when REF_NODEREF is set. This means any errors
     we get will be from the orig_refname, and we can act
     accordingly.

     We already do this in the REF_DELETING case, but we
     should do it for update, too.

  2. If we do get a "refname" return from
     resolve_ref_unsafe(), even with RESOLVE_REF_NO_RECURSE
     it may be the name of the ref pointed-to by a symref.
     We already normalize this back to orig_refname before
     taking the lockfile, but we need to do so before the
     null_oid check.

While we're rearranging the REF_NODEREF handling, we can
also bump the initialization of lflags to the top of the
function, where we are setting up other flags. This saves us
from having yet another conditional block on REF_NODEREF
just to set it later.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-13 09:05:42 -08:00