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Author SHA1 Message Date
Stefan Beller 109cd76dd3 object: add repository argument to parse_object
Add a repository argument to allow the callers of parse_object
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-29 10:43:38 -07:00
Junio C Hamano 50f08db594 Merge branch 'js/use-bug-macro'
Developer support update, by using BUG() macro instead of die() to
mark codepaths that should not happen more clearly.

* js/use-bug-macro:
  BUG_exit_code: fix sparse "symbol not declared" warning
  Convert remaining die*(BUG) messages
  Replace all die("BUG: ...") calls by BUG() ones
  run-command: use BUG() to report bugs, not die()
  test-tool: help verifying BUG() code paths
2018-05-30 14:04:07 +09:00
Junio C Hamano 2f76ebc93c Merge branch 'ma/lockfile-cleanup'
Code clean-up to adjust to a more recent lockfile API convention that
allows lockfile instances kept on the stack.

* ma/lockfile-cleanup:
  lock_file: move static locks into functions
  lock_file: make function-local locks non-static
  refs.c: do not die if locking fails in `delete_pseudoref()`
  refs.c: do not die if locking fails in `write_pseudoref()`
  t/helper/test-write-cache: clean up lock-handling
2018-05-30 14:04:05 +09:00
Martin Ågren b227586831 lock_file: make function-local locks non-static
Placing `struct lock_file`s on the stack used to be a bad idea, because
the temp- and lockfile-machinery would keep a pointer into the struct.
But after 076aa2cbd (tempfile: auto-allocate tempfiles on heap,
2017-09-05), we can safely have lockfiles on the stack. (This applies
even if a user returns early, leaving a locked lock behind.)

These `struct lock_file`s are local to their respective functions and we
can drop their staticness.

For good measure, I have inspected these sites and come to believe that
they always release the lock, with the possible exception of bailing out
using `die()` or `exit()` or by returning from a `cmd_foo()`.

As pointed out by Jeff King, it would be bad if someone held on to a
`struct lock_file *` for some reason. After some grepping, I agree with
his findings: no-one appears to be doing that.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-10 14:54:45 +09:00
Junio C Hamano 174774cd51 Merge branch 'sb/object-store-replace'
The effort to pass the repository in-core structure throughout the
API continues.  This round deals with the code that implements the
refs/replace/ mechanism.

* sb/object-store-replace:
  replace-object: allow lookup_replace_object to handle arbitrary repositories
  replace-object: allow do_lookup_replace_object to handle arbitrary repositories
  replace-object: allow prepare_replace_object to handle arbitrary repositories
  refs: allow for_each_replace_ref to handle arbitrary repositories
  refs: store the main ref store inside the repository struct
  replace-object: add repository argument to lookup_replace_object
  replace-object: add repository argument to do_lookup_replace_object
  replace-object: add repository argument to prepare_replace_object
  refs: add repository argument to for_each_replace_ref
  refs: add repository argument to get_main_ref_store
  replace-object: check_replace_refs is safe in multi repo environment
  replace-object: eliminate replace objects prepared flag
  object-store: move lookup_replace_object to replace-object.h
  replace-object: move replace_map to object store
  replace_object: use oidmap
2018-05-08 15:59:21 +09:00
Johannes Schindelin 033abf97fc Replace all die("BUG: ...") calls by BUG() ones
In d8193743e0 (usage.c: add BUG() function, 2017-05-12), a new macro
was introduced to use for reporting bugs instead of die(). It was then
subsequently used to convert one single caller in 588a538ae5
(setup_git_env: convert die("BUG") to BUG(), 2017-05-12).

The cover letter of the patch series containing this patch
(cf 20170513032414.mfrwabt4hovujde2@sigill.intra.peff.net) is not
terribly clear why only one call site was converted, or what the plan
is for other, similar calls to die() to report bugs.

Let's just convert all remaining ones in one fell swoop.

This trick was performed by this invocation:

	sed -i 's/die("BUG: /BUG("/g' $(git grep -l 'die("BUG' \*.c)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-06 19:06:13 +09:00
Stefan Beller 64a741619d refs: store the main ref store inside the repository struct
This moves the 'main_ref_store', which was a global variable in refs.c
into the repository struct.

This patch does not deal with the parts in the refs subsystem which deal
with the submodules there. A later patch needs to get rid of the submodule
exposure in the refs API, such as 'get_submodule_ref_store(path)'.

Acked-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-12 11:38:56 +09:00
Jeff King fb9c2d2703 refs: use chdir_notify to update cached relative paths
Commit f57f37e2e1 (files-backend: remove the use of
git_path(), 2017-03-26) introduced a regression when a
relative $GIT_DIR is used in a working tree:

  - when we initialize the ref backend, we make a copy of
    get_git_dir(), which may be relative

  - later, we may call setup_work_tree() and chdir to the
    root of the working tree

  - further calls to the ref code will use the stored git
    directory, but relative paths will now point to the
    wrong place

The new test in t1501 demonstrates one such instance (the
bug causes us to write the ref update to the nonsense
"relative/relative/.git").

Since setup_work_tree() now uses chdir_notify, we can just
ask it update our relative paths when necessary.

Reported-by: Rafael Ascensao <rafa.almas@gmail.com>
Helped-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-30 12:50:03 -07:00
Junio C Hamano 2b72ea0a48 Merge branch 'mr/packed-ref-store-fix'
Crash fix for a corner case where an error codepath tried to unlock
what it did not acquire lock on.

* mr/packed-ref-store-fix:
  files_initial_transaction_commit(): only unlock if locked
2018-02-13 13:39:11 -08:00
Mathias Rav 81fcb698e0 files_initial_transaction_commit(): only unlock if locked
Running git clone --single-branch --mirror -b TAGNAME previously
triggered the following error message:

	fatal: multiple updates for ref 'refs/tags/TAGNAME' not allowed.

This error condition is handled in files_initial_transaction_commit().

42c7f7ff9 ("commit_packed_refs(): remove call to `packed_refs_unlock()`", 2017-06-23)
introduced incorrect unlocking in the error path of this function,
which changes the error message to

	fatal: BUG: packed_refs_unlock() called when not locked

Move the call to packed_refs_unlock() above the "cleanup:" label
since the unlocking should only be done in the last error path.

Signed-off-by: Mathias Rav <m@git.strova.dk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-01-19 14:16:56 -08:00
Junio C Hamano 02abc6be8e Merge branch 'mh/avoid-rewriting-packed-refs' into maint
Recent update to the refs infrastructure implementation started
rewriting packed-refs file more often than before; this has been
optimized again for most trivial cases.

* mh/avoid-rewriting-packed-refs:
  files-backend: don't rewrite the `packed-refs` file unnecessarily
  t1409: check that `packed-refs` is not rewritten unnecessarily
2017-12-06 09:08:50 -08:00
Junio C Hamano a97222978a Merge branch 'mh/tidy-ref-update-flags'
Code clean-up in refs API implementation.

* mh/tidy-ref-update-flags:
  refs: update some more docs to use "oid" rather than "sha1"
  write_packed_entry(): take `object_id` arguments
  refs: rename constant `REF_ISPRUNING` to `REF_IS_PRUNING`
  refs: rename constant `REF_NODEREF` to `REF_NO_DEREF`
  refs: tidy up and adjust visibility of the `ref_update` flags
  ref_transaction_add_update(): remove a check
  ref_transaction_update(): die on disallowed flags
  prune_ref(): call `ref_transaction_add_update()` directly
  files_transaction_prepare(): don't leak flags to packed transaction
2017-11-15 12:14:29 +09:00
Junio C Hamano ffb0b5762e Merge branch 'mh/avoid-rewriting-packed-refs'
Recent update to the refs infrastructure implementation started
rewriting packed-refs file more often than before; this has been
optimized again for most trivial cases.

* mh/avoid-rewriting-packed-refs:
  files-backend: don't rewrite the `packed-refs` file unnecessarily
  t1409: check that `packed-refs` is not rewritten unnecessarily
2017-11-15 12:14:27 +09:00
Junio C Hamano e7e456f500 Merge branch 'bc/object-id'
Conversion from uchar[20] to struct object_id continues.

* bc/object-id: (25 commits)
  refs/files-backend: convert static functions to object_id
  refs: convert read_raw_ref backends to struct object_id
  refs: convert peel_object to struct object_id
  refs: convert resolve_ref_unsafe to struct object_id
  worktree: convert struct worktree to object_id
  refs: convert resolve_gitlink_ref to struct object_id
  Convert remaining callers of resolve_gitlink_ref to object_id
  sha1_file: convert index_path and index_fd to struct object_id
  refs: convert reflog_expire parameter to struct object_id
  refs: convert read_ref_at to struct object_id
  refs: convert peel_ref to struct object_id
  builtin/pack-objects: convert to struct object_id
  pack-bitmap: convert traverse_bitmap_commit_list to object_id
  refs: convert dwim_log to struct object_id
  builtin/reflog: convert remaining unsigned char uses to object_id
  refs: convert dwim_ref and expand_ref to struct object_id
  refs: convert read_ref and read_ref_full to object_id
  refs: convert resolve_refdup and refs_resolve_refdup to struct object_id
  Convert check_connected to use struct object_id
  refs: update ref transactions to use struct object_id
  ...
2017-11-06 14:24:27 +09:00
Michael Haggerty 78fb457968 refs: update some more docs to use "oid" rather than "sha1"
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:08 +09:00
Michael Haggerty acedcde76d refs: rename constant `REF_ISPRUNING` to `REF_IS_PRUNING`
Underscores are cheap, and help readability.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:08 +09:00
Michael Haggerty 91774afcc3 refs: rename constant `REF_NODEREF` to `REF_NO_DEREF`
Even after working with this code for years, I still see this constant
name as "ref node ref". Rename it to make it's meaning clearer.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:08 +09:00
Michael Haggerty 5ac95fee3d refs: tidy up and adjust visibility of the `ref_update` flags
The constants used for `ref_update::flags` were rather disorganized:

* The definitions in `refs.h` were not close to the functions that
  used them.

* Maybe constants were defined in `refs-internal.h`, making them
  visible to the whole refs module, when in fact they only made sense
  for the files backend.

* Their documentation wasn't very consistent and partly still referred
  to sha1s rather than oids.

* The numerical values followed no rational scheme

Fix all of these problems. The main functional improvement is that
some constants' visibility is now limited to `files-backend.c`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:07 +09:00
Michael Haggerty 62c72d1fd0 ref_transaction_add_update(): remove a check
We want to make `REF_ISPRUNING` internal to the files backend. For
this to be possible, `ref_transaction_add_update()` mustn't know about
it. So move the check that `REF_ISPRUNING` is only used with
`REF_NODEREF` from this function to `files_transaction_prepare()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:07 +09:00
Michael Haggerty b00f3cfa92 prune_ref(): call `ref_transaction_add_update()` directly
`prune_ref()` needs to use the `REF_ISPRUNING` flag, but we want to
make that flag private to the files backend. So instead of calling
`ref_transaction_delete()`, which is a public function and therefore
shouldn't allow the `REF_ISPRUNING` flag, change `prune_ref()` to call
`ref_transaction_add_update()`, which is private to the refs
module. (Note that we don't need any of the other services provided by
`ref_transaction_delete()`.)

This allows us to change `ref_transaction_update()` to reject the
`REF_ISPRUNING` flag. Do so by adjusting
`REF_TRANSACTION_UPDATE_ALLOWED_FLAGS`. Also add parentheses to its
definition to avoid potential future mishaps.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:07 +09:00
Michael Haggerty b0ca411051 files_transaction_prepare(): don't leak flags to packed transaction
The files backend uses `ref_update::flags` for several internal flags.
But those flags have no meaning to the packed backend. So when adding
updates for the packed-refs transaction, only use flags that make
sense to the packed backend.

`REF_NODEREF` is part of the public interface, and it's logically what
we want, so include it. In fact it is actually ignored by the packed
backend (which doesn't support symbolic references), but that's its
own business.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06 10:31:07 +09:00
Michael Haggerty 7c6bd25c7d files-backend: don't rewrite the `packed-refs` file unnecessarily
Even when we are deleting references, we needn't overwrite the
`packed-refs` file if the references that we are deleting only exist
as loose references. Implement this optimization as follows:

* Add a function `is_packed_transaction_needed()`, which checks
  whether a given packed-refs transaction actually needs to be carried
  out (i.e., it returns false if the transaction obviously wouldn't
  have any effect). This function must be called while holding the
  `packed-refs` lock to avoid races.

* Change `files_transaction_prepare()` to check whether the
  packed-refs transaction is actually needed. If not, squelch it, but
  continue holding the `packed-refs` lock until the end of the
  transaction to avoid races.

This fixes a mild regression caused by dc39e09942 (files_ref_store:
use a transaction to update packed refs, 2017-09-08). Before that
commit, unnecessary rewrites of `packed-refs` were suppressed by
`repack_without_refs()`. But the transaction-based writing introduced
by that commit didn't perform that optimization.

Note that the pre-dc39e09942 code still had to *read* the whole
`packed-refs` file to determine that the rewrite could be skipped, so
the performance for the cases that the write could be elided was
`O(N)` in the number of packed references both before and after
dc39e09942. But after that commit the constant factor increased.

This commit reimplements the optimization of eliding unnecessary
`packed-refs` rewrites. That, plus the fact that since
cfa2e29c34 (packed_ref_store: get rid of the `ref_cache` entirely,
2017-03-17) we don't necessarily have to read the whole `packed-refs`
file at all, means that deletes of one or a few loose references can
now be done with `O(n lg N)` effort, where `n` is the number of loose
references being deleted and `N` is the total number of packed
references.

This commit fixes two tests in t1409.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-30 09:45:15 +09:00
Michael Haggerty ff08e56cde Merge branch 'bc/object-id' into base 2017-10-28 09:27:15 +02:00
Junio C Hamano 4e40fb302e Merge branch 'mh/ref-locking-fix'
Transactions to update multiple references that involves a deletion
was quite broken in an error codepath and did not abort everything
correctly.

* mh/ref-locking-fix:
  files_transaction_prepare(): fix handling of ref lock failure
  t1404: add a bunch of tests of D/F conflicts
2017-10-26 12:29:23 +09:00
Michael Haggerty da5267f1b6 files_transaction_prepare(): fix handling of ref lock failure
Since dc39e09942 (files_ref_store: use a transaction to update packed
refs, 2017-09-08), failure to lock a reference has been handled
incorrectly by `files_transaction_prepare()`. If
`lock_ref_for_update()` fails in the lock-acquisition loop of that
function, it sets `ret` then breaks out of that loop. Prior to
dc39e09942, that was OK, because the only thing following the loop was
the cleanup code. But dc39e09942 added another blurb of code between
the loop and the cleanup. That blurb sometimes resets `ret` to zero,
making the cleanup code think that the locking was successful.

Specifically, whenever

* One or more reference deletions have been processed successfully in
  the lock-acquisition loop. (Processing the first such reference
  causes a packed-ref transaction to be initialized.)

* Then `lock_ref_for_update()` fails for a subsequent reference. Such
  a failure can happen for a number of reasons, such as the old SHA-1
  not being correct, lock contention, etc. This causes a `break` out
  of the lock-acquisition loop.

* The `packed-refs` lock is acquired successfully and
  `ref_transaction_prepare()` succeeds for the packed-ref transaction.
  This has the effect of resetting `ret` back to 0, and making the
  cleanup code think that lock acquisition was successful.

In that case, any reference updates that were processed prior to
breaking out of the loop would be carried out (loose and packed), but
the reference that couldn't be locked and any subsequent references
would silently be ignored.

This can easily cause data loss if, for example, the user was trying
to push a new name for an existing branch while deleting the old name.
After the push, the branch could be left unreachable, and could even
subsequently be garbage-collected.

This problem was noticed in the context of deleting one reference and
creating another in a single transaction, when the two references D/F
conflict with each other, like

    git update-ref --stdin <<EOF
    delete refs/foo
    create refs/foo/bar HEAD
    EOF

This triggers the above bug because the deletion is processed
successfully for `refs/foo`, then the D/F conflict causes
`lock_ref_for_update()` to fail when `refs/foo/bar` is processed. In
this case the transaction *should* fail, but instead it causes
`refs/foo` to be deleted without creating `refs/foo`. This could
easily result in data loss.

The fix is simple: instead of just breaking out of the loop, jump
directly to the cleanup code. This fixes some tests in t1404 that were
added in the previous commit.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-25 15:08:26 +09:00
brian m. carlson 4f01e5080c refs/files-backend: convert static functions to object_id
Convert several static functions to take pointers to struct object_id.
Change the relevant parameters to write_packed_entry to be const, as we
don't modify them.  Rename lock_ref_sha1_basic to lock_ref_oid_basic to
reflect its new argument.  Update the docstring for verify lock to
account for the new parameter name, and note additionally that the
old_oid may be NULL.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:52 +09:00
brian m. carlson 99afe91a6c refs: convert read_raw_ref backends to struct object_id
Convert the unsigned char * parameter to struct object_id * for
files_read_raw_ref and packed_read_raw_ref.  Update the documentation.
Switch from using get_sha1_hex and a hard-coded 40 to using
parse_oid_hex.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:52 +09:00
brian m. carlson 49e61479be refs: convert resolve_ref_unsafe to struct object_id
Convert resolve_ref_unsafe to take a pointer to struct object_id by
converting one remaining caller to use struct object_id, removing the
temporary NULL pointer check in expand_ref, converting the declaration
and definition, and applying the following semantic patch:

@@
expression E1, E2, E3, E4;
@@
- resolve_ref_unsafe(E1, E2, E3.hash, E4)
+ resolve_ref_unsafe(E1, E2, &E3, E4)

@@
expression E1, E2, E3, E4;
@@
- resolve_ref_unsafe(E1, E2, E3->hash, E4)
+ resolve_ref_unsafe(E1, E2, E3, E4)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:51 +09:00
brian m. carlson 0155f710b8 refs: convert reflog_expire parameter to struct object_id
reflog_expire already used struct object_id internally, but it did not
take it as a parameter.  Adjust the parameter (and the callers) to pass
a pointer to struct object_id instead of a pointer to unsigned char.
Remove the temporary inserted earlier as it is no longer required.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:51 +09:00
brian m. carlson 34c290a6fc refs: convert read_ref and read_ref_full to object_id
All but two of the call sites already have parameters using the hash
parameter of struct object_id, so convert them to take a pointer to the
struct directly.  Also convert refs_read_refs_full, the underlying
implementation.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:50 +09:00
brian m. carlson 89f3bbdd3b refs: update ref transactions to use struct object_id
Update the ref transaction code to use struct object_id.  Remove one
NULL pointer check which was previously inserted around a dereference;
since we now pass a pointer to struct object_id directly through, the
code we're calling handles this for us.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:50 +09:00
brian m. carlson 2616a5e508 refs: convert delete_ref and refs_delete_ref to struct object_id
Convert delete_ref and refs_delete_ref to take a pointer to struct
object_id.  Update the documentation accordingly, including referring to
null_oid in lowercase, as it is not a #define constant.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:50 +09:00
brian m. carlson 49e9958869 refs/files-backend: convert struct ref_to_prune to object_id
Change the member of this struct to be a struct object_id.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-16 11:05:50 +09:00
Junio C Hamano efe9d6ce33 Merge branch 'rs/resolve-ref-optional-result'
Code clean-up.

* rs/resolve-ref-optional-result:
  refs: pass NULL to resolve_refdup() if hash is not needed
  refs: pass NULL to refs_resolve_refdup() if hash is not needed
2017-10-05 13:48:19 +09:00
Junio C Hamano 1a2e1a76ec Merge branch 'mh/mmap-packed-refs'
Operations that do not touch (majority of) packed refs have been
optimized by making accesses to packed-refs file lazy; we no longer
pre-parse everything, and an access to a single ref in the
packed-refs does not touch majority of irrelevant refs, either.

* mh/mmap-packed-refs: (21 commits)
  packed-backend.c: rename a bunch of things and update comments
  mmapped_ref_iterator: inline into `packed_ref_iterator`
  ref_cache: remove support for storing peeled values
  packed_ref_store: get rid of the `ref_cache` entirely
  ref_store: implement `refs_peel_ref()` generically
  packed_read_raw_ref(): read the reference from the mmapped buffer
  packed_ref_iterator_begin(): iterate using `mmapped_ref_iterator`
  read_packed_refs(): ensure that references are ordered when read
  packed_ref_cache: keep the `packed-refs` file mmapped if possible
  packed-backend.c: reorder some definitions
  mmapped_ref_iterator_advance(): no peeled value for broken refs
  mmapped_ref_iterator: add iterator over a packed-refs file
  packed_ref_cache: remember the file-wide peeling state
  read_packed_refs(): read references with minimal copying
  read_packed_refs(): make parsing of the header line more robust
  read_packed_refs(): only check for a header at the top of the file
  read_packed_refs(): use mmap to read the `packed-refs` file
  die_unterminated_line(), die_invalid_line(): new functions
  packed_ref_cache: add a backlink to the associated `packed_ref_store`
  prefix_ref_iterator: break when we leave the prefix
  ...
2017-10-03 15:42:50 +09:00
Junio C Hamano cb1083ca23 Merge branch 'jk/read-in-full'
Code clean-up to prevent future mistakes by copying and pasting
code that checks the result of read_in_full() function.

* jk/read-in-full:
  worktree: check the result of read_in_full()
  worktree: use xsize_t to access file size
  distinguish error versus short read from read_in_full()
  avoid looking at errno for short read_in_full() returns
  prefer "!=" when checking read_in_full() result
  notes-merge: drop dead zero-write code
  files-backend: prefer "0" for write_in_full() error check
2017-10-03 15:42:49 +09:00
Junio C Hamano 3b48045c6c Merge branch 'sd/branch-copy'
"git branch" learned "-c/-C" to create a new branch by copying an
existing one.

* sd/branch-copy:
  branch: fix "copy" to never touch HEAD
  branch: add a --copy (-c) option to go with --move (-m)
  branch: add test for -m renaming multiple config sections
  config: create a function to format section headers
2017-10-03 15:42:48 +09:00
René Scharfe 872ccb2c69 refs: pass NULL to refs_resolve_refdup() if hash is not needed
This gets us rid of a write-only variable.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-01 17:26:58 +09:00
Junio C Hamano 73ecdc606e Merge branch 'rs/resolve-ref-optional-result'
Code clean-up.

* rs/resolve-ref-optional-result:
  refs: pass NULL to resolve_ref_unsafe() if hash is not needed
  refs: pass NULL to refs_resolve_ref_unsafe() if hash is not needed
  refs: make sha1 output parameter of refs_resolve_ref_unsafe() optional
2017-09-28 14:47:56 +09:00
Jeff King 88780c37b3 files-backend: prefer "0" for write_in_full() error check
Commit 06f46f237a (avoid "write_in_full(fd, buf, len) !=
len" pattern, 2017-09-13) converted this callsite from:

  write_in_full(...) != 1

to

  write_in_full(...) < 0

But during the conflict resolution in c50424a6f0 (Merge
branch 'jk/write-in-full-fix', 2017-09-25), this morphed
into

  write_in_full(...) < 1

This behaves as we want, but we prefer to avoid modeling the
"less than length" error-check which can be subtly buggy, as
shown in efacf609c8 (config: avoid "write_in_full(fd, buf,
len) < len" pattern, 2017-09-13).

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-26 12:54:43 +09:00
Michael Haggerty ba1c052fa6 ref_store: implement `refs_peel_ref()` generically
We're about to stop storing packed refs in a `ref_cache`. That means
that the only way we have left to optimize `peel_ref()` is by checking
whether the reference being peeled is the one currently being iterated
over (in `current_ref_iter`), and if so, using `ref_iterator_peel()`.
But this can be done generically; it doesn't have to be implemented
per-backend.

So implement `refs_peel_ref()` in `refs.c` and remove the `peel_ref()`
method from the refs API.

This removes the last callers of a couple of functions, so delete
them. More cleanup to come...

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-25 18:02:46 +09:00
Junio C Hamano c50424a6f0 Merge branch 'jk/write-in-full-fix'
Many codepaths did not diagnose write failures correctly when disks
go full, due to their misuse of write_in_full() helper function,
which have been corrected.

* jk/write-in-full-fix:
  read_pack_header: handle signed/unsigned comparison in read result
  config: flip return value of store_write_*()
  notes-merge: use ssize_t for write_in_full() return value
  pkt-line: check write_in_full() errors against "< 0"
  convert less-trivial versions of "write_in_full() != len"
  avoid "write_in_full(fd, buf, len) != len" pattern
  get-tar-commit-id: check write_in_full() return against 0
  config: avoid "write_in_full(fd, buf, len) < len" pattern
2017-09-25 15:24:06 +09:00
René Scharfe e691b027b6 refs: pass NULL to refs_resolve_ref_unsafe() if hash is not needed
This allows us to get rid of two write-only variables, one of them
being a SHA1 buffer.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-24 10:18:18 +09:00
Junio C Hamano 07f0542da3 Merge branch 'mh/packed-ref-transactions'
Implement transactional update to the packed-ref representation of
references.

* mh/packed-ref-transactions:
  files_transaction_finish(): delete reflogs before references
  packed-backend: rip out some now-unused code
  files_ref_store: use a transaction to update packed refs
  t1404: demonstrate two problems with reference transactions
  files_initial_transaction_commit(): use a transaction for packed refs
  prune_refs(): also free the linked list
  files_pack_refs(): use a reference transaction to write packed refs
  packed_delete_refs(): implement method
  packed_ref_store: implement reference transactions
  struct ref_transaction: add a place for backends to store data
  packed-backend: don't adjust the reference count on lock/unlock
2017-09-19 10:47:56 +09:00
Junio C Hamano 89563ec379 Merge branch 'jk/incore-lockfile-removal'
The long-standing rule that an in-core lockfile instance, once it
is used, must not be freed, has been lifted and the lockfile and
tempfile APIs have been updated to reduce the chance of programming
errors.

* jk/incore-lockfile-removal:
  stop leaking lock structs in some simple cases
  ref_lock: stop leaking lock_files
  lockfile: update lifetime requirements in documentation
  tempfile: auto-allocate tempfiles on heap
  tempfile: remove deactivated list entries
  tempfile: use list.h for linked list
  tempfile: release deactivated strbufs instead of resetting
  tempfile: robustify cleanup handler
  tempfile: factor out deactivation
  tempfile: factor out activation
  tempfile: replace die("BUG") with BUG()
  tempfile: handle NULL tempfile pointers gracefully
  tempfile: prefer is_tempfile_active to bare access
  lockfile: do not rollback lock on failed close
  tempfile: do not delete tempfile on failed close
  always check return value of close_tempfile
  verify_signed_buffer: prefer close_tempfile() to close()
  setup_temporary_shallow: move tempfile struct into function
  setup_temporary_shallow: avoid using inactive tempfile
  write_index_as_tree: cleanup tempfile on error
2017-09-19 10:47:53 +09:00
Junio C Hamano 8a044c7f1d Merge branch 'nd/prune-in-worktree'
"git gc" and friends when multiple worktrees are used off of a
single repository did not consider the index and per-worktree refs
of other worktrees as the root for reachability traversal, making
objects that are in use only in other worktrees to be subject to
garbage collection.

* nd/prune-in-worktree:
  refs.c: reindent get_submodule_ref_store()
  refs.c: remove fallback-to-main-store code get_submodule_ref_store()
  rev-list: expose and document --single-worktree
  revision.c: --reflog add HEAD reflog from all worktrees
  files-backend: make reflog iterator go through per-worktree reflog
  revision.c: --all adds HEAD from all worktrees
  refs: remove dead for_each_*_submodule()
  refs.c: move for_each_remote_ref_submodule() to submodule.c
  revision.c: use refs_for_each*() instead of for_each_*_submodule()
  refs: add refs_head_ref()
  refs: move submodule slash stripping code to get_submodule_ref_store
  refs.c: refactor get_submodule_ref_store(), share common free block
  revision.c: --indexed-objects add objects from all worktrees
  revision.c: refactor add_index_objects_to_pending()
  refs.c: use is_dir_sep() in resolve_gitlink_ref()
  revision.h: new flag in struct rev_info wrt. worktree-related refs
2017-09-19 10:47:53 +09:00
Junio C Hamano dafbe1993e Merge branch 'ma/split-symref-update-fix'
A leakfix.

* ma/split-symref-update-fix:
  refs/files-backend: add `refname`, not "HEAD", to list
  refs/files-backend: correct return value in lock_ref_for_update
  refs/files-backend: fix memory leak in lock_ref_for_update
  refs/files-backend: add longer-scoped copy of string to list
2017-09-19 10:47:53 +09:00
Michael Haggerty 8738a8a4df ref_iterator: keep track of whether the iterator output is ordered
References are iterated over in order by refname, but reflogs are not.
Some consumers of reference iteration care about the difference. Teach
each `ref_iterator` to keep track of whether its output is ordered.

`overlay_ref_iterator` is one of the picky consumers. Add a sanity
check in `overlay_ref_iterator_begin()` to verify that its inputs are
ordered.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-14 15:19:07 +09:00
Jeff King 564bde9ae6 convert less-trivial versions of "write_in_full() != len"
The prior commit converted many sites to check the return
value of write_in_full() for negativity, rather than a
mismatch with the input length. This patch covers similar
cases, but where the return value is stored in an
intermediate variable. These should get the same treatment,
but they need to be reviewed more carefully since it would
be a bug if the return value is stored in an unsigned type
(which indeed, it is in one of the cases).

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-14 15:17:59 +09:00
Jeff King 06f46f237a avoid "write_in_full(fd, buf, len) != len" pattern
The return value of write_in_full() is either "-1", or the
requested number of bytes[1]. If we make a partial write
before seeing an error, we still return -1, not a partial
value. This goes back to f6aa66cb95 (write_in_full: really
write in full or return error on disk full., 2007-01-11).

So checking anything except "was the return value negative"
is pointless. And there are a couple of reasons not to do
so:

  1. It can do a funny signed/unsigned comparison. If your
     "len" is signed (e.g., a size_t) then the compiler will
     promote the "-1" to its unsigned variant.

     This works out for "!= len" (unless you really were
     trying to write the maximum size_t bytes), but is a
     bug if you check "< len" (an example of which was fixed
     recently in config.c).

     We should avoid promoting the mental model that you
     need to check the length at all, so that new sites are
     not tempted to copy us.

  2. Checking for a negative value is shorter to type,
     especially when the length is an expression.

  3. Linus says so. In d34cf19b89 (Clean up write_in_full()
     users, 2007-01-11), right after the write_in_full()
     semantics were changed, he wrote:

       I really wish every "write_in_full()" user would just
       check against "<0" now, but this fixes the nasty and
       stupid ones.

     Appeals to authority aside, this makes it clear that
     writing it this way does not have an intentional
     benefit. It's a historical curiosity that we never
     bothered to clean up (and which was undoubtedly
     cargo-culted into new sites).

So let's convert these obviously-correct cases (this
includes write_str_in_full(), which is just a wrapper for
write_in_full()).

[1] A careful reader may notice there is one way that
    write_in_full() can return a different value. If we ask
    write() to write N bytes and get a return value that is
    _larger_ than N, we could return a larger total. But
    besides the fact that this would imply a totally broken
    version of write(), it would already invoke undefined
    behavior. Our internal remaining counter is an unsigned
    size_t, which means that subtracting too many byte will
    wrap it around to a very large number. So we'll instantly
    begin reading off the end of the buffer, trying to write
    gigabytes (or petabytes) of data.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-14 15:17:59 +09:00
Martin Ågren 276d0e35c0 refs/files-backend: add `refname`, not "HEAD", to list
An earlier patch rewrote `split_symref_update()` to add a copy of a
string to a string list instead of adding the original string. That was
so that the original string could be freed in a later patch, but it is
also conceptually cleaner, since now all calls to `string_list_insert()`
and `string_list_append()` add `update->refname`. --- Except a literal
"HEAD" is added in `split_head_update()`.

Restructure `split_head_update()` in the same way as the earlier patch
did for `split_symref_update()`. This does not correct any practical
problem, but makes things conceptually cleaner. The downside is a call
to `string_list_has_string()`, which should be relatively cheap.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-10 16:36:58 +09:00
Martin Ågren 3f5ef95b5e refs/files-backend: correct return value in lock_ref_for_update
In one code path we return a literal -1 and not a symbolic constant. The
value -1 would be interpreted as TRANSACTION_NAME_CONFLICT, which is
wrong. Use TRANSACTION_GENERIC_ERROR instead (that is the only other
return value we have to choose from).

Noticed-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-10 16:36:58 +09:00
Martin Ågren 851e1fbd01 refs/files-backend: fix memory leak in lock_ref_for_update
After the previous patch, none of the functions we call hold on to
`referent.buf`, so we can safely release the string buffer before
returning.

Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-10 16:36:58 +09:00
Martin Ågren c299468bd7 refs/files-backend: add longer-scoped copy of string to list
split_symref_update() receives a string-pointer `referent` and adds it
to the list of `affected_refnames`. The list simply holds on to the
pointers it is given, it does not copy the strings and it does not ever
free them. The `referent` string in split_symref_update() belongs to a
string buffer in the caller. After we return, the string will be leaked.

In the next patch, we want to properly release the string buffer in the
caller, but we can't safely do so until we've made sure that
`affected_refnames` will not be holding on to a pointer to the string.
We could configure the list to handle its own resources, but it would
mean some alloc/free-churning. The list is already handling other
strings (through other code paths) which we do not need to worry about,
and we'd be memory-churning those strings too, completely unnecessary.

Observe that split_symref_update() creates a `new_update`-object through
ref_transaction_add_update(), after which `new_update->refname` is a
copy of `referent`. The difference is, this copy will be freed, and it
will be freed *after* `affected_refnames` has been cleared.

Rearrange the handling of `referent`, so that we don't add it directly
to `affected_refnames`. Instead, first just check whether `referent`
exists in the string list, and later add `new_update->refname`.

Helped-by: Michael Haggerty <mhagger@alum.mit.edu>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-10 16:36:58 +09:00
Michael Haggerty 5e00a6c873 files_transaction_finish(): delete reflogs before references
If the deletion steps unexpectedly fail, it is less bad to leave a
reference without its reflog than it is to leave a reflog without its
reference, since the latter is an invalid repository state.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09 03:18:04 +09:00
Michael Haggerty dc39e09942 files_ref_store: use a transaction to update packed refs
When processing a `files_ref_store` transaction, it is sometimes
necessary to delete some references from the "packed-refs" file. Do
that using a reference transaction conducted against the
`packed_ref_store`.

This change further decouples `files_ref_store` from
`packed_ref_store`. It also fixes multiple problems, including the two
revealed by test cases added in the previous commit.

First, the old code didn't obtain the `packed-refs` lock until
`files_transaction_finish()`. This means that a failure to acquire the
`packed-refs` lock (e.g., due to contention with another process)
wasn't detected until it was too late (problems like this are supposed
to be detected in the "prepare" phase). The new code acquires the
`packed-refs` lock in `files_transaction_prepare()`, the same stage of
the processing when the loose reference locks are being acquired,
removing another reason why the "prepare" phase might succeed and the
"finish" phase might nevertheless fail.

Second, the old code deleted the loose version of a reference before
deleting any packed version of the same reference. This left a moment
when another process might think that the packed version of the
reference is current, which is incorrect. (Even worse, the packed
version of the reference can be arbitrarily old, and might even point
at an object that has since been garbage-collected.)

Third, if a reference deletion fails to acquire the `packed-refs` lock
altogether, then the old code might leave the repository in the
incorrect state (possibly corrupt) described in the previous
paragraph.

Now we activate the new "packed-refs" file (sans any references that
are being deleted) *before* deleting the corresponding loose
references. But we hold the "packed-refs" lock until after the loose
references have been finalized, thus preventing a simultaneous
"pack-refs" process from packing the loose version of the reference in
the time gap, which would otherwise defeat our attempt to delete it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09 03:18:04 +09:00
Michael Haggerty 1444bfe027 files_initial_transaction_commit(): use a transaction for packed refs
Use a `packed_ref_store` transaction in the implementation of
`files_initial_transaction_commit()` rather than using internal
features of the packed ref store. This further decouples
`files_ref_store` from `packed_ref_store`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09 03:18:04 +09:00
Michael Haggerty 22b09cdfad prune_refs(): also free the linked list
At least since v1.7, the elements of the `refs_to_prune` linked list
have been leaked. Fix the leak by teaching `prune_refs()` to free the
list elements as it processes them.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09 03:18:04 +09:00
Michael Haggerty 27d03d04d5 files_pack_refs(): use a reference transaction to write packed refs
Now that the packed reference store supports transactions, we can use
a transaction to write the packed versions of references that we want
to pack. This decreases the coupling between `files_ref_store` and
`packed_ref_store`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09 03:18:04 +09:00
Michael Haggerty 2fb330ca72 packed_delete_refs(): implement method
Implement `packed_delete_refs()` using a reference transaction. This
means that `files_delete_refs()` can use `refs_delete_refs()` instead
of `repack_without_refs()` to delete any packed references, decreasing
the coupling between the classes.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-09 03:18:04 +09:00
Jeff King ee4d8e455c ref_lock: stop leaking lock_files
Since the tempfile code recently relaxed the rule that
tempfile structs (and thus locks) need to hang around
forever, we no longer have to leak our lock_file structs.

In fact, we don't even need to heap-allocate them anymore,
since their lifetime can just match that of the surrounding
ref_lock (and if we forget to delete a lock, the effect is
the same as before: it will eventually go away at program
exit).

Note that there is a check in unlock_ref() to only rollback
a lock file if it has been allocated. We don't need that
check anymore; we zero the ref_lock (and thus the
lock_file), so at worst we pass a NULL pointer to
delete_tempfile(), which considers that a noop.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-06 17:19:54 +09:00
Jeff King 076aa2cbda tempfile: auto-allocate tempfiles on heap
The previous commit taught the tempfile code to give up
ownership over tempfiles that have been renamed or deleted.
That makes it possible to use a stack variable like this:

  struct tempfile t;

  create_tempfile(&t, ...);
  ...
  if (!err)
          rename_tempfile(&t, ...);
  else
          delete_tempfile(&t);

But doing it this way has a high potential for creating
memory errors. The tempfile we pass to create_tempfile()
ends up on a global linked list, and it's not safe for it to
go out of scope until we've called one of those two
deactivation functions.

Imagine that we add an early return from the function that
forgets to call delete_tempfile(). With a static or heap
tempfile variable, the worst case is that the tempfile hangs
around until the program exits (and some functions like
setup_shallow_temporary rely on this intentionally, creating
a tempfile and then leaving it for later cleanup).

But with a stack variable as above, this is a serious memory
error: the variable goes out of scope and may be filled with
garbage by the time the tempfile code looks at it.  Let's
see if we can make it harder to get this wrong.

Since many callers need to allocate arbitrary numbers of
tempfiles, we can't rely on static storage as a general
solution. So we need to turn to the heap. We could just ask
all callers to pass us a heap variable, but that puts the
burden on them to call free() at the right time.

Instead, let's have the tempfile code handle the heap
allocation _and_ the deallocation (when the tempfile is
deactivated and removed from the list).

This changes the return value of all of the creation
functions. For the cleanup functions (delete and rename),
we'll add one extra bit of safety: instead of taking a
tempfile pointer, we'll take a pointer-to-pointer and set it
to NULL after freeing the object. This makes it safe to
double-call functions like delete_tempfile(), as the second
call treats the NULL input as a noop. Several callsites
follow this pattern.

The resulting patch does have a fair bit of noise, as each
caller needs to be converted to handle:

  1. Storing a pointer instead of the struct itself.

  2. Passing the pointer instead of taking the struct
     address.

  3. Handling a "struct tempfile *" return instead of a file
     descriptor.

We could play games to make this less noisy. For example, by
defining the tempfile like this:

  struct tempfile {
	struct heap_allocated_part_of_tempfile {
                int fd;
                ...etc
        } *actual_data;
  }

Callers would continue to have a "struct tempfile", and it
would be "active" only when the inner pointer was non-NULL.
But that just makes things more awkward in the long run.
There aren't that many callers, so we can simply bite
the bullet and adjust all of them. And the compiler makes it
easy for us to find them all.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-06 17:19:54 +09:00
Jeff King 83a3069a38 lockfile: do not rollback lock on failed close
Since the lockfile code is based on the tempfile code, it
has some of the same problems, including that close_lock_file()
erases the tempfile's filename buf, making it hard for the
caller to write a good error message.

In practice this comes up less for lockfiles than for
straight tempfiles, since we usually just report the
refname. But there is at least one buggy case in
write_ref_to_lockfile(). Besides, given the coupling between
the lockfile and tempfile modules, it's less confusing if
their close() functions have the same semantics.

Just as the previous commit did for close_tempfile(), let's
teach close_lock_file() and its wrapper close_ref() not to
rollback on error. And just as before, we'll give them new
"gently" names to catch any new callers that are added.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-06 17:19:53 +09:00
Junio C Hamano f2dd90fc1c Merge branch 'mh/ref-lock-entry'
The code to acquire a lock on a reference (e.g. while accepting a
push from a client) used to immediately fail when the reference is
already locked---now it waits for a very short while and retries,
which can make it succeed if the lock holder was holding it during
a read-only operation.

* mh/ref-lock-entry:
  refs: retry acquiring reference locks for 100ms
2017-08-26 22:55:09 -07:00
Nguyễn Thái Ngọc Duy 944b4e3013 files-backend: make reflog iterator go through per-worktree reflog
refs/bisect is unfortunately per-worktree, so we need to look in
per-worktree logs/refs/bisect in addition to per-repo logs/refs. The
current iterator only goes through per-repo logs/refs.

Use merge iterator to walk two ref stores at the same time and pick
per-worktree refs from the right iterator.

PS. Note the unsorted order of for_each_reflog in the test. This is
supposed to be OK, for now. If we enforce order on for_each_reflog()
then some more work will be required.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-24 14:57:56 -07:00
Michael Haggerty 4ff0f01cb7 refs: retry acquiring reference locks for 100ms
The philosophy of reference locking has been, "if another process is
changing a reference, then whatever I'm trying to do to it will
probably fail anyway because my old-SHA-1 value is probably no longer
current". But this argument falls down if the other process has locked
the reference to do something that doesn't actually change the value
of the reference, such as `pack-refs` or `reflog expire`. There
actually *is* a decent chance that a planned reference update will
still be able to go through after the other process has released the
lock.

So when trying to lock an individual reference (e.g., when creating
"refs/heads/master.lock"), if it is already locked, then retry the
lock acquisition for approximately 100 ms before giving up. This
should eliminate some unnecessary lock conflicts without wasting a lot
of time.

Add a configuration setting, `core.filesRefLockTimeout`, to allow this
setting to be tweaked.

Note: the function `get_files_ref_lock_timeout_ms()` cannot be private
to the files backend because it is also used by `write_pseudoref()`
and `delete_pseudoref()`, which are defined in `refs.c` so that they
can be used by other reference backends.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23 10:37:21 -07:00
Junio C Hamano 44c2339e55 Merge branch 'mh/packed-ref-store'
The "ref-store" code reorganization continues.

* mh/packed-ref-store: (32 commits)
  files-backend: cheapen refname_available check when locking refs
  packed_ref_store: handle a packed-refs file that is a symlink
  read_packed_refs(): die if `packed-refs` contains bogus data
  t3210: add some tests of bogus packed-refs file contents
  repack_without_refs(): don't lock or unlock the packed refs
  commit_packed_refs(): remove call to `packed_refs_unlock()`
  clear_packed_ref_cache(): don't protest if the lock is held
  packed_refs_unlock(), packed_refs_is_locked(): new functions
  packed_refs_lock(): report errors via a `struct strbuf *err`
  packed_refs_lock(): function renamed from lock_packed_refs()
  commit_packed_refs(): use a staging file separate from the lockfile
  commit_packed_refs(): report errors rather than dying
  packed_ref_store: make class into a subclass of `ref_store`
  packed-backend: new module for handling packed references
  packed_read_raw_ref(): new function, replacing `resolve_packed_ref()`
  packed_ref_store: support iteration
  packed_peel_ref(): new function, extracted from `files_peel_ref()`
  repack_without_refs(): take a `packed_ref_store *` parameter
  get_packed_ref(): take a `packed_ref_store *` parameter
  rollback_packed_refs(): take a `packed_ref_store *` parameter
  ...
2017-08-22 10:29:16 -07:00
Michael Haggerty 8ec617c80c files-backend: cheapen refname_available check when locking refs
When locking references in preparation for updating them, we need to
check that none of the newly added references D/F conflict with
existing references (e.g., we don't allow `refs/foo` to be added if
`refs/foo/bar` already exists, or vice versa).

Prior to 524a9fdb51 (refs_verify_refname_available(): use function in
more places, 2017-04-16), conflicts with existing loose references
were checked by looking directly in the filesystem, and then conflicts
with existing packed references were checked by running
`verify_refname_available_dir()` against the packed-refs cache.

But that commit changed the final check to call
`refs_verify_refname_available()` against the *whole* files ref-store,
including both loose and packed references, with the following
comment:

> This means that those callsites now check for conflicts with all
> references rather than just packed refs, but the performance cost
> shouldn't be significant (and will be regained later).

That comment turned out to be too sanguine. User s@kazlauskas.me
reported that fetches involving a very large number of references in
neighboring directories were slowed down by that change.

The problem is that when fetching, each reference is updated
individually, within its own reference transaction. This is done
because some reference updates might succeed even though others fail.
But every time a reference update transaction is finished,
`clear_loose_ref_cache()` is called. So when it is time to update the
next reference, part of the loose ref cache has to be repopulated for
the `refs_verify_refname_available()` call. If the references are all
in neighboring directories, then the cost of repopulating the
reference cache increases with the number of references, resulting in
O(N²) effort.

The comment above also claims that the performance cost "will be
regained later". The idea was that once the packed-refs were finished
being split out into a separate ref-store, we could limit the
`refs_verify_refname_available()` call to the packed references again.
That is what we do now.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-17 14:32:23 -07:00
Michael Haggerty e5cc7d7d2b repack_without_refs(): don't lock or unlock the packed refs
Change `repack_without_refs()` to expect the packed-refs lock to be
held already, and not to release the lock before returning. Change the
callers to deal with lock management.

This change makes it possible for callers to hold the packed-refs lock
for a longer span of time, a possibility that will eventually make it
possible to fix some longstanding races.

The only semantic change here is that `repack_without_refs()` used to
forget to release the lock in the `if (!removed)` exit path. That
omission is now fixed.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-03 10:01:56 -07:00
Junio C Hamano 5c83d850d0 Merge branch 'mh/packed-ref-store-prep'
Bugfix for a topic that is (only) in 'master'.

* mh/packed-ref-store-prep:
  for_each_bisect_ref(): don't trim refnames
  lock_packed_refs(): fix cache validity check
2017-06-26 14:09:29 -07:00
Junio C Hamano 50f03c6676 Merge branch 'ab/free-and-null'
A common pattern to free a piece of memory and assign NULL to the
pointer that used to point at it has been replaced with a new
FREE_AND_NULL() macro.

* ab/free-and-null:
  *.[ch] refactoring: make use of the FREE_AND_NULL() macro
  coccinelle: make use of the "expression" FREE_AND_NULL() rule
  coccinelle: add a rule to make "expression" code use FREE_AND_NULL()
  coccinelle: make use of the "type" FREE_AND_NULL() rule
  coccinelle: add a rule to make "type" code use FREE_AND_NULL()
  git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL
2017-06-24 14:28:41 -07:00
Junio C Hamano f31d23a399 Merge branch 'bw/config-h'
Fix configuration codepath to pay proper attention to commondir
that is used in multi-worktree situation, and isolate config API
into its own header file.

* bw/config-h:
  config: don't implicitly use gitdir or commondir
  config: respect commondir
  setup: teach discover_git_directory to respect the commondir
  config: don't include config.h by default
  config: remove git_config_iter
  config: create config.h
2017-06-24 14:28:41 -07:00
Michael Haggerty 42c7f7ff96 commit_packed_refs(): remove call to `packed_refs_unlock()`
Instead, change the callers of `commit_packed_refs()` to call
`packed_refs_unlock()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:33 -07:00
Michael Haggerty c8bed835c2 packed_refs_lock(): report errors via a `struct strbuf *err`
That way the callers don't have to come up with error messages
themselves.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:33 -07:00
Michael Haggerty b7de57d8d1 packed_refs_lock(): function renamed from lock_packed_refs()
Rename `lock_packed_refs()` to `packed_refs_lock()` for consistency
with how other methods are named. Also, it's about to get some
companions.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:33 -07:00
Michael Haggerty 3478983b51 commit_packed_refs(): report errors rather than dying
Report errors via a `struct strbuf *err` rather than by calling
`die()`. To enable this goal, change `write_packed_entry()` to report
errors via a return value and `errno` rather than dying.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:33 -07:00
Michael Haggerty e0cc8ac820 packed_ref_store: make class into a subclass of `ref_store`
Add the infrastructure to make `packed_ref_store` implement
`ref_store`, at least formally (few of the methods are actually
implemented yet). Change the functions in its interface to take
`ref_store *` arguments. Change `files_ref_store` to store a pointer
to `ref_store *` and to call functions via the virtual `ref_store`
interface where possible. This also means that a few
`packed_ref_store` functions can become static.

This is a work in progress. Some more `ref_store` methods will soon be
implemented (e.g., those having to do with reference transactions).
But some of them will never be implemented (e.g., those having to do
with symrefs or reflogs).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:33 -07:00
Michael Haggerty 67be7c5a59 packed-backend: new module for handling packed references
Now that the interface between `files_ref_store` and
`packed_ref_store` is relatively narrow, move the latter into a new
module, "refs/packed-backend.h" and "refs/packed-backend.c". It still
doesn't quite implement the `ref_store` interface, but it will soon.

This commit moves code around and adjusts its visibility, but doesn't
change anything.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty d13fa1a9ba packed_read_raw_ref(): new function, replacing `resolve_packed_ref()`
Add a new function, `packed_read_raw_ref()`, which is nearly a
`read_raw_ref_fn`. Use it in place of `resolve_packed_ref()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 38b86e81ae packed_ref_store: support iteration
Add the infrastructure to iterate over a `packed_ref_store`. It's a
lot of boilerplate, but it's all part of a campaign to make
`packed_ref_store` implement `ref_store`. In the future, this iterator
will work much differently.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 6dc6ba7092 packed_peel_ref(): new function, extracted from `files_peel_ref()`
This will later become a method of `packed_ref_store`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 0f199b1ee0 repack_without_refs(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty f3f9724940 get_packed_ref(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 38e3fe6dec rollback_packed_refs(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty cf30b3e88b commit_packed_refs(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty f512f0f32c lock_packed_refs(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty e70b70294e add_packed_ref(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty a9169f5dc2 get_packed_refs(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 8e821c38f7 get_packed_ref_cache(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 25e0c5faf2 validate_packed_ref_cache(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 9c4fe0ff95 clear_packed_ref_cache(): take a `packed_ref_store *` parameter
It only cares about the packed-refs part of the reference store.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 139c4596ad packed_ref_store: move `packed_refs_lock` member here
Move the `packed_refs_lock` member from `files_ref_store` to
`packed_ref_store`, and rename it to `lock` since it's now more
obvious what it is locking.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty e0d483970b packed_ref_store: move `packed_refs_path` here
Move `packed_refs_path` from `files_ref_store` to `packed_ref_store`,
and rename it to `path` since its meaning is clear from its new
context.

Inline `files_packed_refs_path()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty bdf55fa6b2 packed_ref_store: new struct
Start extracting the packed-refs-related data structures into a new
class, `packed_ref_store`. It doesn't yet implement `ref_store`, but
it will.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Michael Haggerty 2f10882166 add_packed_ref(): teach function to overwrite existing refs
Teach `add_packed_ref()` to overwrite an existing entry if one already
exists for the specified `refname`. This means that we can call it
from `files_pack_refs()`, thereby reducing the amount that the latter
function needs to know about the internals of packed-reference
handling.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-23 13:27:32 -07:00
Sahil Dua 52d59cc645 branch: add a --copy (-c) option to go with --move (-m)
Add the ability to --copy a branch and its reflog and configuration,
this uses the same underlying machinery as the --move (-m) option
except the reflog and configuration is copied instead of being moved.

This is useful for e.g. copying a topic branch to a new version,
e.g. work to work-2 after submitting the work topic to the list, while
preserving all the tracking info and other configuration that goes
with the branch, and unlike --move keeping the other already-submitted
branch around for reference.

Like --move, when the source branch is the currently checked out
branch the HEAD is moved to the destination branch. In the case of
--move we don't really have a choice (other than remaining on a
detached HEAD) and in order to keep the functionality consistent, we
are doing it in similar way for --copy too.

The most common usage of this feature is expected to be moving to a
new topic branch which is a copy of the current one, in that case
moving to the target branch is what the user wants, and doesn't
unexpectedly behave differently than --move would.

One outstanding caveat of this implementation is that:

    git checkout maint &&
    git checkout master &&
    git branch -c topic &&
    git checkout -

Will check out 'maint' instead of 'master'. This is because the @{-N}
feature (or its -1 shorthand "-") relies on HEAD reflogs created by
the checkout command, so in this case we'll checkout maint instead of
master, as the user might expect. What to do about that is left to a
future change.

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Sahil Dua <sahildua2305@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-18 21:47:59 -07:00
Ævar Arnfjörð Bjarmason 6a83d90207 coccinelle: make use of the "type" FREE_AND_NULL() rule
Apply the result of the just-added coccinelle rule. This manually
excludes a few occurrences, mostly things that resulted in many
FREE_AND_NULL() on one line, that'll be manually fixed in a subsequent
change.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-16 12:44:03 -07:00
Brandon Williams b2141fc1d2 config: don't include config.h by default
Stop including config.h by default in cache.h.  Instead only include
config.h in those files which require use of the config system.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-15 12:56:22 -07:00
Michael Haggerty fed6ebebf1 lock_packed_refs(): fix cache validity check
Commit 28ed9830b1 (get_packed_ref_cache(): assume "packed-refs" won't
change while locked, 2017-05-22) assumes that the "packed-refs" file
cannot change while we hold the lock. That assumption is
justified *if* the lock has been held the whole time since the
"packed-refs" file was last read.

But in `lock_packed_refs()`, we ourselves lock the "packed-refs" file
and then call `get_packed_ref_cache()` to ensure that the cache agrees
with the file. The intent is to guard against the possibility that
another process changed the "packed-refs" file the moment before we
locked it.

This check was defeated because `get_packed_ref_cache()` saw that the
file was locked, and therefore didn't do the `stat_validity_check()`
that we want.

The mistake was compounded with a misleading comment in
`lock_packed_refs()` claiming that it was doing the right thing. That
comment came from an earlier draft of the mh/packed-ref-store-prep
patch series when the commits were in a different order.

So instead:

* Extract a function `validate_packed_ref_cache()` that does the
  validity check independent of whether the lock is held.

* Change `get_packed_ref_cache()` to call the new function, but only
  if the lock *isn't* held.

* Change `lock_packed_refs()` to call the new function in any case
  before calling `get_packed_ref_cache()`.

* Fix the comment in `lock_packed_refs()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-12 10:11:36 -07:00
Michael Haggerty c1da06c6f1 create_ref_entry(): remove `check_name` option
Only one caller was using it, so move the check to that caller.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:56 +09:00
Michael Haggerty 0a0865b8f1 refs_ref_iterator_begin(): handle `GIT_REF_PARANOIA`
Instead of handling `GIT_REF_PARANOIA` in
`files_ref_iterator_begin()`, handle it in
`refs_ref_iterator_begin()`, where it will cover all reference stores.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:56 +09:00
Michael Haggerty 89c571da56 read_packed_refs(): report unexpected fopen() failures
The old code ignored any errors encountered when trying to fopen the
"packed-refs" file, treating all such failures as if the file didn't
exist. But it could be that there is some other error opening the
file (e.g., permissions problems), and we don't want to silently
ignore such problems. So report any failures that are not due to
ENOENT.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:56 +09:00
Michael Haggerty 099a912a27 read_packed_refs(): do more of the work of reading packed refs
Teach `read_packed_refs()` to also

* Allocate and initialize the new `packed_ref_cache`
* Open and close the `packed-refs` file
* Update the `validity` field of the new object

This decreases the coupling between `packed_refs_cache` and
`files_ref_store` by a little bit.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty 28ed9830b1 get_packed_ref_cache(): assume "packed-refs" won't change while locked
If we've got the "packed-refs" file locked, then it can't change;
there's no need to keep calling `stat_validity_check()` on it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty 531cc4a56d should_pack_ref(): new function, extracted from `files_pack_refs()`
Extract a function for deciding whether a reference should be packed.
It is a self-contained bit of logic, so splitting it out improves
readability.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty 2ced105cb1 ref_update_reject_duplicates(): expose function to whole refs module
It will soon have some other users.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty 30173b8851 ref_transaction_prepare(): new optional step for reference updates
In the future, compound reference stores will sometimes need to modify
references in two different reference stores at the same time, meaning
that a single logical reference transaction might have to be
implemented as two internal sub-transactions. They won't want to call
`ref_transaction_commit()` for the two sub-transactions one after the
other, because that wouldn't be atomic (the first commit could succeed
and the second one fail). Instead, they will want to prepare both
sub-transactions (i.e., obtain any necessary locks and do any
pre-checks), and only if both prepare steps succeed, then commit both
sub-transactions.

Start preparing for that day by adding a new, optional
`ref_transaction_prepare()` step to the reference transaction
sequence, which obtains the locks and does any prechecks, reporting
any errors that occur. Also add a `ref_transaction_abort()` function
that can be used to abort a sub-transaction even if it has already
been prepared.

That is on the side of the public-facing API. On the side of the
`ref_store` VTABLE, get rid of `transaction_commit` and instead add
methods `transaction_prepare`, `transaction_finish`, and
`transaction_abort`. A `ref_transaction_commit()` now basically calls
methods `transaction_prepare` then `transaction_finish`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty 8d4240d3c8 ref_transaction_commit(): check for valid `transaction->state`
Move the check that `transaction->state` is valid from
`files_transaction_commit()` to `ref_transaction_commit()`, where
other future reference backends can benefit from it as well.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty c0ca935764 files_transaction_cleanup(): new helper function
Extract the cleanup functionality from `files_transaction_commit()`
into a new function. It will soon have another caller.

Use the common cleanup code even on early exit if the transaction is
empty, to reduce code duplication.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:55 +09:00
Michael Haggerty 00d174489e files_ref_store: put the packed files lock directly in this struct
Instead of using a global `lock_file` instance for the main
"packed-refs" file and using a pointer in `files_ref_store` to keep
track of whether it is locked, embed the `lock_file` instance directly
in the `files_ref_store` struct and use the new
`is_lock_file_locked()` function to keep track of whether it is
locked. This keeps related data together and makes the main reference
store less of a special case.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:54 +09:00
Michael Haggerty 55c6bc37c9 files-backend: move `lock` member to `files_ref_store`
Move the `lock` member from `packed_ref_cache` to `files_ref_store`,
since at most one cache can have a locked "packed-refs" file
associated with it. Rename it to `packed_refs_lock` to make its
purpose clearer in its new home. More changes are coming here shortly.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:54 +09:00
Michael Haggerty 64da41993a ref_store: take a `msg` parameter when deleting references
Just because the files backend can't retain reflogs for deleted
references is no reason that they shouldn't be supported by the
virtual method interface. Also, `delete_ref()` and `refs_delete_ref()`
have already gained `msg` parameters. Now let's add them to
`delete_refs()` and `refs_delete_refs()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:53 +09:00
Michael Haggerty 43a2dfde76 refs: use `size_t` indexes when iterating over ref transaction updates
Eliminate any chance of integer overflow on platforms where the two
types have different sizes.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:53 +09:00
Michael Haggerty 04aea8d4df files-backend: use `die("BUG: ...")`, not `die("internal error: ...")`
The former is by far more common in our codebase.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-23 14:29:52 +09:00
Junio C Hamano ca7b2ab07d Merge branch 'bc/object-id'
* bc/object-id: (53 commits)
  object: convert parse_object* to take struct object_id
  tree: convert parse_tree_indirect to struct object_id
  sequencer: convert do_recursive_merge to struct object_id
  diff-lib: convert do_diff_cache to struct object_id
  builtin/ls-tree: convert to struct object_id
  merge: convert checkout_fast_forward to struct object_id
  sequencer: convert fast_forward_to to struct object_id
  builtin/ls-files: convert overlay_tree_on_cache to object_id
  builtin/read-tree: convert to struct object_id
  sha1_name: convert internals of peel_onion to object_id
  upload-pack: convert remaining parse_object callers to object_id
  revision: convert remaining parse_object callers to object_id
  revision: rename add_pending_sha1 to add_pending_oid
  http-push: convert process_ls_object and descendants to object_id
  refs/files-backend: convert many internals to struct object_id
  refs: convert struct ref_update to use struct object_id
  ref-filter: convert some static functions to struct object_id
  Convert struct ref_array_item to struct object_id
  Convert the verify_pack callback to struct object_id
  Convert lookup_tag to struct object_id
  ...
2017-05-23 14:29:19 +09:00
Junio C Hamano b15667bbdc Merge branch 'js/larger-timestamps'
Some platforms have ulong that is smaller than time_t, and our
historical use of ulong for timestamp would mean they cannot
represent some timestamp that the platform allows.  Invent a
separate and dedicated timestamp_t (so that we can distingiuish
timestamps and a vanilla ulongs, which along is already a good
move), and then declare uintmax_t is the type to be used as the
timestamp_t.

* js/larger-timestamps:
  archive-tar: fix a sparse 'constant too large' warning
  use uintmax_t for timestamps
  date.c: abort if the system time cannot handle one of our timestamps
  timestamp_t: a new data type for timestamps
  PRItime: introduce a new "printf format" for timestamps
  parse_timestamp(): specify explicitly where we parse timestamps
  t0006 & t5000: skip "far in the future" test when time_t is too limited
  t0006 & t5000: prepare for 64-bit timestamps
  ref-filter: avoid using `unsigned long` for catch-all data type
2017-05-16 11:51:59 +09:00
Junio C Hamano 4b44b7b1df Merge branch 'nd/worktree-kill-parse-ref'
"git gc" did not interact well with "git worktree"-managed
per-worktree refs.

* nd/worktree-kill-parse-ref:
  refs: kill set_worktree_head_symref()
  worktree.c: kill parse_ref() in favor of refs_resolve_ref_unsafe()
  refs: introduce get_worktree_ref_store()
  refs: add REFS_STORE_ALL_CAPS
  refs.c: make submodule ref store hashmap generic
  environment.c: fix potential segfault by get_git_common_dir()
2017-05-16 11:51:51 +09:00
brian m. carlson c251c83df2 object: convert parse_object* to take struct object_id
Make parse_object, parse_object_or_die, and parse_object_buffer take a
pointer to struct object_id.  Remove the temporary variables inserted
earlier, since they are no longer necessary.  Transform all of the
callers using the following semantic patch:

@@
expression E1;
@@
- parse_object(E1.hash)
+ parse_object(&E1)

@@
expression E1;
@@
- parse_object(E1->hash)
+ parse_object(E1)

@@
expression E1, E2;
@@
- parse_object_or_die(E1.hash, E2)
+ parse_object_or_die(&E1, E2)

@@
expression E1, E2;
@@
- parse_object_or_die(E1->hash, E2)
+ parse_object_or_die(E1, E2)

@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1.hash, E2, E3, E4, E5)
+ parse_object_buffer(&E1, E2, E3, E4, E5)

@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1->hash, E2, E3, E4, E5)
+ parse_object_buffer(E1, E2, E3, E4, E5)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:58 +09:00
brian m. carlson 4417df8c49 refs/files-backend: convert many internals to struct object_id
Convert many of the internals of the files backend to use struct
object_id.  Avoid converting public APIs (except one change to
refs/ref-cache.c) to limit the scope of the changes.

Convert one use of get_sha1_hex to parse_oid_hex, and rely on the fact
that a strbuf will be NUL-terminated and that parse_oid_hex will fail on
truncated input to avoid the need to check the length.

This is a requirement to convert parse_object later on.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:58 +09:00
brian m. carlson 984912989d refs: convert struct ref_update to use struct object_id
Convert struct ref_array_item to use struct object_id by changing the
definition and applying the following semantic patch, plus the standard
object_id transforms:

@@
struct ref_update E1;
@@
- E1.new_sha1
+ E1.new_oid.hash

@@
struct ref_update *E1;
@@
- E1->new_sha1
+ E1->new_oid.hash

@@
struct ref_update E1;
@@
- E1.old_sha1
+ E1.old_oid.hash

@@
struct ref_update *E1;
@@
- E1->old_sha1
+ E1->old_oid.hash

This transformation allows us to convert write_ref_to_lockfile, which is
required to convert parse_object.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:58 +09:00
brian m. carlson 4322478a49 reflog_expire: convert to struct object_id
Adjust the callback functions to take struct object_id * instead of
unsigned char *, and modify related static functions accordingly.

Introduce a temporary object_id instance into files_reflog_expire and
copy the SHA-1 value passed in.  This is necessary because the sha1
parameter can come indirectly from get_sha1.  Without the temporary, it
would require much more refactoring to be able to convert this function.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:57 +09:00
Johannes Schindelin dddbad728c timestamp_t: a new data type for timestamps
Git's source code assumes that unsigned long is at least as precise as
time_t. Which is incorrect, and causes a lot of problems, in particular
where unsigned long is only 32-bit (notably on Windows, even in 64-bit
versions).

So let's just use a more appropriate data type instead. In preparation
for this, we introduce the new `timestamp_t` data type.

By necessity, this is a very, very large patch, as it has to replace all
timestamps' data type in one go.

As we will use a data type that is not necessarily identical to `time_t`,
we need to be very careful to use `time_t` whenever we interact with the
system functions, and `timestamp_t` everywhere else.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-27 13:07:39 +09:00
Junio C Hamano 77b34eaa07 Merge branch 'mh/separate-ref-cache'
The internals of the refs API around the cached refs has been
streamlined.

* mh/separate-ref-cache:
  do_for_each_entry_in_dir(): delete function
  files_pack_refs(): use reference iteration
  commit_packed_refs(): use reference iteration
  cache_ref_iterator_begin(): make function smarter
  get_loose_ref_cache(): new function
  get_loose_ref_dir(): function renamed from get_loose_refs()
  do_for_each_entry_in_dir(): eliminate `offset` argument
  refs: handle "refs/bisect/" in `loose_fill_ref_dir()`
  ref-cache: use a callback function to fill the cache
  refs: record the ref_store in ref_cache, not ref_dir
  ref-cache: introduce a new type, ref_cache
  refs: split `ref_cache` code into separate files
  ref-cache: rename `remove_entry()` to `remove_entry_from_dir()`
  ref-cache: rename `find_ref()` to `find_ref_entry()`
  ref-cache: rename `add_ref()` to `add_ref_entry()`
  refs_verify_refname_available(): use function in more places
  refs_verify_refname_available(): implement once for all backends
  refs_ref_iterator_begin(): new function
  refs_read_raw_ref(): new function
  get_ref_dir(): don't call read_loose_refs() for "refs/bisect"
2017-04-26 15:39:13 +09:00
Nguyễn Thái Ngọc Duy d026a25657 refs: kill set_worktree_head_symref()
70999e9cec (branch -m: update all per-worktree HEADs - 2016-03-27)
added this function in order to update HEADs of all relevant
worktrees, when a branch is renamed.

It, as a public ref api, kind of breaks abstraction when it uses
internal functions of files backend. With the introduction of
refs_create_symref(), we can move back pretty close to the code before
70999e9cec, where create_symref() was used for updating HEAD.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-24 21:28:55 -07:00
Junio C Hamano f9096db54b Merge branch 'rs/misc-cppcheck-fixes'
Various small fixes.

* rs/misc-cppcheck-fixes:
  server-info: avoid calling fclose(3) twice in update_info_file()
  files_for_each_reflog_ent_reverse(): close stream and free strbuf on error
  am: close stream on error, but not stdin
2017-04-23 22:07:56 -07:00
Johannes Schindelin cb71f8bdb5 PRItime: introduce a new "printf format" for timestamps
Currently, Git's source code treats all timestamps as if they were
unsigned longs. Therefore, it is okay to write "%lu" when printing them.

There is a substantial problem with that, though: at least on Windows,
time_t is *larger* than unsigned long, and hence we will want to switch
away from the ill-specified `unsigned long` data type.

So let's introduce the pseudo format "PRItime" (currently simply being
defined to "lu") to make it easier to change the data type used for
timestamps.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-23 20:19:15 -07:00
Johannes Schindelin 1aeb7e756c parse_timestamp(): specify explicitly where we parse timestamps
Currently, Git's source code represents all timestamps as `unsigned
long`. In preparation for using a more appropriate data type, let's
introduce a symbol `parse_timestamp` (currently being defined to
`strtoul`) where appropriate, so that we can later easily switch to,
say, use `strtoull()` instead.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-23 20:19:15 -07:00
René Scharfe be686f03e0 files_for_each_reflog_ent_reverse(): close stream and free strbuf on error
Exit the loop orderly through the cleanup code, instead of dashing out
with logfp still open and sb leaking.

Found with Cppcheck.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: Jeff King <peff@peff.net>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-17 17:37:10 -07:00
Michael Haggerty 50c2d8555b files_pack_refs(): use reference iteration
Use reference iteration rather than `do_for_each_entry_in_dir()` in
the definition of `files_pack_refs()`. This makes the code shorter and
easier to follow, because the logic can be inline rather than spread
between the main function and a callback function, and it removes the
need to use `pack_refs_cb_data` to preserve intermediate state.

This removes the last callers of `entry_resolves_to_object()` and
`get_loose_ref_dir()`, so delete those functions.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty 1710fbafb6 commit_packed_refs(): use reference iteration
Use reference iteration rather than do_for_each_entry_in_dir() in the
definition of commit_packed_refs().

Note that an internal consistency check that was previously done in
`write_packed_entry_fn()` is not there anymore. This is actually an
improvement:

The old error message was emitted when there is an entry in the
packed-ref cache that is not `REF_KNOWS_PEELED`, and when we attempted
to peel the reference, the result was `PEEL_INVALID`,
`PEEL_IS_SYMREF`, or `PEEL_BROKEN`. Since a packed ref cannot be a
symref, `PEEL_IS_SYMREF` and `PEEL_BROKEN` can be ruled out. So we're
left with `PEEL_INVALID`.

An entry without `REF_KNOWS_PEELED` can get into the packed-refs cache
in the following two ways:

* The reference was read from a `packed-refs` file that didn't have
  the `fully-peeled` attribute. In that case, we *don't want* to emit
  an error, because the broken value is presumably a stale value of
  the reference that is now masked by a loose version of the same
  reference (which we just don't happen to be packing this time). This
  is a perfectly legitimate situation and doesn't indicate that the
  repository is corrupt. The old code incorrectly emits an error
  message in this case. (It was probably never reported as a bug
  because this scenario is rare.)

* The reference was a loose reference that was just added to the
  packed ref cache by `files_packed_refs()` via
  `pack_if_possible_fn()` in preparation for being packed. The latter
  function refuses to pack a reference for which
  `entry_resolves_to_object()` returns false, and otherwise calls
  `peel_entry()` itself and checks the return value. So an entry added
  this way should always have `REF_KNOWS_PEELED` and shouldn't trigger
  the error message in either the old code or the new.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty 059ae35a48 cache_ref_iterator_begin(): make function smarter
Change `cache_ref_iterator_begin()` to take two new arguments:

* `prefix` -- to iterate only over references with the specified
  prefix.

* `prime_dir` -- to "prime" (i.e., pre-load) the cache before starting
  the iteration.

The new functionality makes it possible for
`files_ref_iterator_begin()` to be made more ignorant of the internals
of `ref_cache`, and `find_containing_dir()` and `prime_ref_dir()` to
be made private.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty a714b19ca8 get_loose_ref_cache(): new function
Extract a new function, `get_loose_ref_cache()`, from
get_loose_ref_dir(). The function returns the `ref_cache` for the
loose refs of a `files_ref_store`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty 86f423584b get_loose_ref_dir(): function renamed from get_loose_refs()
The new name is more analogous to `get_packed_ref_dir()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty 5c7bba77b2 do_for_each_entry_in_dir(): eliminate `offset` argument
It was never used.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty e3bf2989ca refs: handle "refs/bisect/" in `loose_fill_ref_dir()`
That "refs/bisect/" has to be handled specially when filling the
ref_cache for loose references is a peculiarity of the files backend,
and the ref-cache code shouldn't need to know about it. So move this
code to the callback function, `loose_fill_ref_dir()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty df30875987 ref-cache: use a callback function to fill the cache
It is a leveling violation for `ref_cache` to know about
`files_ref_store` or that it should call `read_loose_refs()` to lazily
fill cache directories. So instead, have its constructor take as an
argument a callback function that it should use for lazy-filling, and
change `files_ref_store` to supply a pointer to function
`read_loose_refs` (renamed to `loose_fill_ref_dir`) when creating the
ref cache for its loose refs.

This means that we can generify the type of the back-pointer in
`struct ref_cache` from `files_ref_store` to `ref_store`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty e00d1a4ff7 refs: record the ref_store in ref_cache, not ref_dir
Instead of keeping a pointer to the `ref_store` in every `ref_dir`
entry, store it once in `struct ref_cache`, and change `struct
ref_dir` to include a pointer to its containing `ref_cache` instead.
This makes it easier to add to the information that is accessible from
a `ref_dir` without increasing the size of every `ref_dir` instance.

Note that previously, every `ref_dir` pointed at the containing
`files_ref_store` regardless of whether it was a part of the loose or
packed reference cache. Now we have to be sure to initialize the
instances to point at the correct containing `ref_cache`. So change
`create_dir_entry()` to take a `ref_cache` parameter, and change its
callers to pass the correct `ref_cache` depending on the purpose of
the new `dir_entry`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty 7c22bc8a18 ref-cache: introduce a new type, ref_cache
For now, it just wraps a `ref_entry *` that points at the root of the
tree. Soon it will hold more information.

Add two new functions, `create_ref_cache()` and `free_ref_cache()`.
Make `free_ref_entry()` private.

Change files-backend to use this type to hold its caches.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:46 -07:00
Michael Haggerty 958f964691 refs: split `ref_cache` code into separate files
The `ref_cache` code is currently too tightly coupled to
`files-backend`, making the code harder to understand and making it
awkward for new code to use `ref_cache` (as we indeed have planned).
Start loosening that coupling by splitting `ref_cache` into a separate
module.

This commit moves code, adds declarations, and changes the visibility
of some functions, but doesn't change any code.

The modules are still too tightly coupled, but the situation will be
improved in subsequent commits.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:45 -07:00
Michael Haggerty 9fc3b06311 ref-cache: rename `remove_entry()` to `remove_entry_from_dir()`
This function's visibility is about to be increased, so give it a more
distinctive name.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:45 -07:00
Michael Haggerty bc1c696e89 ref-cache: rename `find_ref()` to `find_ref_entry()`
This function's visibility is about to be increased, so give it a more
distinctive name.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:45 -07:00
Michael Haggerty a3ade2baba ref-cache: rename `add_ref()` to `add_ref_entry()`
This function's visibility is about to be increased, so give it a more
distinctive name.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:45 -07:00
Michael Haggerty 524a9fdb51 refs_verify_refname_available(): use function in more places
Change `lock_raw_ref()` and `lock_ref_sha1_basic()` to use
`refs_verify_refname_available()` instead of
`verify_refname_available_dir()`. This means that those callsites now
check for conflicts with all references rather than just packed refs,
but the performance cost shouldn't be significant (and will be
regained later).

These were the last callers of `verify_refname_available_dir()`, so
also delete that (very complicated) function.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:45 -07:00
Michael Haggerty b05855b5bc refs_verify_refname_available(): implement once for all backends
It turns out that we can now implement
`refs_verify_refname_available()` based on the other virtual
functions, so there is no need for it to be defined at the backend
level. Instead, define it once in `refs.c` and remove the
`files_backend` definition.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-16 21:32:45 -07:00
Michael Haggerty 68fb02e40d get_ref_dir(): don't call read_loose_refs() for "refs/bisect"
Since references under "refs/bisect/" are per-worktree, they have to
be sought in the worktree rather than in the main repository. But
since loose references are found by traversing directories, the
reference iterator won't even get the idea to look for a
"refs/bisect/" directory in the worktree if there is not a directory
with that name in the main repository. Thus `get_ref_dir()` manually
inserts a dir_entry for "refs/bisect/" whenever it reads the entry for
"refs/".

The current code then immediately calls `read_loose_refs()` on that
directory. But since the dir_entry is created with its `incomplete`
flag set, any traversal that gets to this point will read the
directory automatically. So there is no need to call
`read_loose_refs()` explicitly; the lazy mechanism suffices.

And in fact, the attempt to `read_loose_refs()` was broken anyway.
That function needs its `dirname` argument to have a trailing `/`
character, but the invocation here was passing it "refs/bisect"
without a trailing slash. So `read_loose_refs()` would read
`$GIT_DIR/refs/bisect" correctly, but if it found an entry "foo" in
that directory, it would try to read "$GIT_DIR/refs/bisectfoo".
Normally it wouldn't find anything at that path, but the failure was
canceled out because `get_ref_dir()` *also* forgot to reset the
`REF_INCOMPLETE` bit on the dir_entry. So the read was attempted again
when it was accessed, via the lazy mechanism, and this time the read
was done correctly.

This code has been broken since it was first introduced.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-14 03:54:31 -07:00
Nguyễn Thái Ngọc Duy 2f40e95472 files-backend: avoid ref api targeting main ref store
A small step towards making files-backend work as a non-main ref store
using the newly added store-aware API.

For the record, `join` and `nm` on refs.o and files-backend.o tell me
that files-backend no longer uses functions that default to
get_main_ref_store().

I'm not yet comfortable at the idea of removing
files_assert_main_repository() (or converting REF_STORE_MAIN to
REF_STORE_WRITE). More staring and testing is required before that can
happen. Well, except peel_ref(). I'm pretty sure that function is safe.

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 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