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492 commits

Author SHA1 Message Date
Junio C Hamano
ae7dd1a492 Merge branch 'dt/refs-check-refname-component-optim'
* dt/refs-check-refname-component-optim:
  refs.c: optimize check_refname_component()
2014-06-16 12:18:52 -07:00
Junio C Hamano
bb0ced7581 Merge branch 'rs/read-ref-at'
* rs/read-ref-at:
  refs.c: change read_ref_at to use the reflog iterators
2014-06-16 12:18:48 -07:00
Junio C Hamano
474df928b1 Merge branch 'jl/remote-rm-prune'
"git remote rm" and "git remote prune" can involve removing many
refs at once, which is not a very efficient thing to do when very
many refs exist in the packed-refs file.

* jl/remote-rm-prune:
  remote prune: optimize "dangling symref" check/warning
  remote: repack packed-refs once when deleting multiple refs
  remote rm: delete remote configuration as the last
2014-06-16 12:17:58 -07:00
Junio C Hamano
f7f349e138 Merge branch 'rs/reflog-exists'
* rs/reflog-exists:
  checkout.c: use ref_exists instead of file_exist
  refs.c: add new functions reflog_exists and delete_reflog
2014-06-06 11:23:04 -07:00
David Turner
dde8a902c7 refs.c: optimize check_refname_component()
In a repository with many refs, check_refname_component can be a major
contributor to the runtime of some git commands. One such command is

git rev-parse HEAD

Timings for one particular repo, with about 60k refs, almost all
packed, are:

Old: 35 ms
New: 29 ms

Many other commands which read refs are also sped up.

Signed-off-by: David Turner <dturner@twitter.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-05 15:24:50 -07:00
Ronnie Sahlberg
4207ed285f refs.c: change read_ref_at to use the reflog iterators
read_ref_at has its own parsing of the reflog file for no really good reason
so lets change this to use the existing reflog iterators. This removes one
instance where we manually unmarshall the reflog file format.

Remove the now redundant ref_msg function.

Log messages for errors are changed slightly. We no longer print the file
name for the reflog, instead we refer to it as 'Log for ref <refname>'.
This might be a minor useability regression, but I don't really think so, since
experienced users would know where the log is anyway and inexperienced users
would not know what to do about/how to repair 'Log ... has gap ...' anyway.

Adapt the t1400 test to handle the change in log messages.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-03 11:09:32 -07:00
Jens Lindström
e6bea66db6 remote prune: optimize "dangling symref" check/warning
When 'git remote prune' was used to delete many refs in a repository
with many refs, a lot of time was spent checking for (now) dangling
symbolic refs pointing to the deleted ref, since warn_dangling_symref()
was once per deleted ref to check all other refs in the repository.

Avoid this using the new warn_dangling_symrefs() function which
makes one pass over all refs and checks for all the deleted refs in
one go, after they have all been deleted.

Signed-off-by: Jens Lindström <jl@opera.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-05-27 12:30:47 -07:00
Jens Lindström
c9e768bb77 remote: repack packed-refs once when deleting multiple refs
When 'git remote rm' or 'git remote prune' were used in a repository
with many refs, and needed to delete many remote-tracking refs, a lot
of time was spent deleting those refs since for each deleted ref,
repack_without_refs() was called to rewrite packed-refs without just
that deleted ref.

To avoid this, call repack_without_refs() first to repack without all
the refs that will be deleted, before calling delete_ref() to delete
each one completely.  The call to repack_without_ref() in delete_ref()
then becomes a no-op, since packed-refs already won't contain any of
the deleted refs.

Signed-off-by: Jens Lindström <jl@opera.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-05-27 12:30:42 -07:00
Ronnie Sahlberg
4da588357a refs.c: add new functions reflog_exists and delete_reflog
Add two new functions, reflog_exists and delete_reflog, to hide the internal
reflog implementation (that they are files under .git/logs/...) from callers.
Update checkout.c to use these functions in update_refs_for_switch instead of
building pathnames and calling out to file access functions. Update reflog.c
to use these to check if the reflog exists. Now there are still many places
in reflog.c where we are still leaking the reflog storage implementation but
this at least reduces the number of such dependencies by one. Finally
change two places in refs.c itself to use the new function to check if a ref
exists or not isntead of build-path-and-stat(). Now, this is strictly not all
that important since these are in parts of refs that are implementing the
actual file storage backend but on the other hand it will not hurt either.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Acked-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-05-08 14:31:43 -07:00
Michael Haggerty
6a402338ec ref_transaction_commit(): work with transaction->updates in place
Now that we free the transaction when we are done, there is no need to
make a copy of transaction->updates before working with it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:16 -07:00
Michael Haggerty
84178db76f struct ref_update: add a type field
It used to be that ref_transaction_commit() allocated a temporary
array to hold the types of references while it is working.  Instead,
add a type field to ref_update that ref_transaction_commit() can use
as its scratch space.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:15 -07:00
Michael Haggerty
81c960e4dc struct ref_update: add a lock field
Now that we manage ref_update objects internally, we can use them to
hold some of the scratch space we need when actually carrying out the
updates.  Store the (struct ref_lock *) there.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:15 -07:00
Michael Haggerty
cb198d21d3 ref_transaction_commit(): simplify code using temporary variables
Use temporary variables in the for-loop blocks to simplify expressions
in the rest of the loop.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:15 -07:00
Michael Haggerty
88615910db struct ref_update: store refname as a FLEX_ARRAY
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:15 -07:00
Michael Haggerty
5524e2416e struct ref_update: rename field "ref_name" to "refname"
This is consistent with the usual nomenclature.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:15 -07:00
Michael Haggerty
b5c8ea2afb refs: remove API function update_refs()
It has been superseded by reference transactions.  This also means
that struct ref_update can become private.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:14 -07:00
Michael Haggerty
caa4046c4f refs: add a concept of a reference transaction
Build out the API for dealing with a bunch of reference checks and
changes within a transaction.  Define an opaque ref_transaction type
that is managed entirely within refs.c.  Introduce functions for
beginning a transaction, adding updates to a transaction, and
committing/rolling back a transaction.

This API will soon replace update_refs().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:14 -07:00
Michael Haggerty
595deb8da6 update_refs(): fix constness
The old signature of update_refs() required a
(const struct ref_update **) for its updates_orig argument.  The
"const" is presumably there to promise that the function will not
modify the contents of the structures.

But this declaration does not permit the function to be called with a
(struct ref_update **), which is perfectly legitimate.  C's type
system is not powerful enough to express what we'd like.  So remove
the first "const" from the declaration.

On the other hand, the function *can* promise not to modify the
pointers within the array that is passed to it without inconveniencing
its callers.  So add a "const" that has that effect, making the final
declaration
(struct ref_update * const *).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:11 -07:00
Michael Haggerty
f412411245 refs.h: rename the action_on_err constants
Given that these constants are only being used when updating
references, it is inappropriate to give them such generic names as
"DIE_ON_ERR".  So prefix their names with "UPDATE_REFS_".

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 12:09:11 -07:00
Junio C Hamano
006f678780 Merge branch 'sh/use-hashcpy'
* sh/use-hashcpy:
  Use hashcpy() when copying object names
2014-03-18 13:51:05 -07:00
Sun He
50546b15ed Use hashcpy() when copying object names
We invented hashcpy() to keep the abstraction of "object name"
behind it.  Use it instead of calling memcpy() with hard-coded
20-byte length when moving object names between pieces of memory.

Leave ppc/sha1.c as-is, because the function is about the SHA-1 hash
algorithm whose output is and will always be 20 bytes.

Helped-by: Michael Haggerty <mhagger@alum.mit.edu>
Helped-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Sun He <sunheehnus@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-06 14:03:12 -08:00
Nguyễn Thái Ngọc Duy
eb07894fe0 use wildmatch() directly without fnmatch() wrapper
Make it clear that we don't use fnmatch() anymore.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-20 14:15:46 -08:00
Junio C Hamano
d0956cfa8e Merge branch 'mh/safe-create-leading-directories'
Code clean-up and protection against concurrent write access to the
ref namespace.

* mh/safe-create-leading-directories:
  rename_tmp_log(): on SCLD_VANISHED, retry
  rename_tmp_log(): limit the number of remote_empty_directories() attempts
  rename_tmp_log(): handle a possible mkdir/rmdir race
  rename_ref(): extract function rename_tmp_log()
  remove_dir_recurse(): handle disappearing files and directories
  remove_dir_recurse(): tighten condition for removing unreadable dir
  lock_ref_sha1_basic(): if locking fails with ENOENT, retry
  lock_ref_sha1_basic(): on SCLD_VANISHED, retry
  safe_create_leading_directories(): add new error value SCLD_VANISHED
  cmd_init_db(): when creating directories, handle errors conservatively
  safe_create_leading_directories(): introduce enum for return values
  safe_create_leading_directories(): always restore slash at end of loop
  safe_create_leading_directories(): split on first of multiple slashes
  safe_create_leading_directories(): rename local variable
  safe_create_leading_directories(): add explicit "slash" pointer
  safe_create_leading_directories(): reduce scope of local variable
  safe_create_leading_directories(): fix format of "if" chaining
2014-01-27 10:45:33 -08:00
Junio C Hamano
9bb5287098 Merge branch 'mh/retire-ref-fetch-rules'
Code simplification.

* mh/retire-ref-fetch-rules:
  refname_match(): always use the rules in ref_rev_parse_rules
2014-01-27 10:44:07 -08:00
Michael Haggerty
08f555cb82 rename_tmp_log(): on SCLD_VANISHED, retry
If safe_create_leading_directories() fails because a file along the
path unexpectedly vanished, try again from the beginning.  Try at most
4 times.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-21 13:47:28 -08:00
Michael Haggerty
f1e9e9a4db rename_tmp_log(): limit the number of remote_empty_directories() attempts
This doesn't seem to be a likely error, but we've got the counter
anyway, so we might as well use it for an added bit of safety.

Please note that the first call to rename() is optimistic, and it is
normal for it to fail if there is a directory in the way.  So bump the
total number of allowed attempts to 4, to be sure that we can still
have at least 3 retries in the case of a race.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-21 13:47:24 -08:00
Michael Haggerty
ae4a283e3b rename_tmp_log(): handle a possible mkdir/rmdir race
If a directory vanishes while renaming the temporary reflog file,
retry (up to 3 times).  This could happen if another process deletes
the directory created by safe_create_leading_directories() just before
we rename the file into the directory.

As far as I can tell, this race could not occur internal to git.  The
only time that a directory under $GIT_DIR/logs is deleted is if room
has to be made for a log file for a reference with the same name;
for example, in the following sequence:

    git branch foo/bar    # Creates file .git/logs/refs/heads/foo/bar
    git branch -d foo/bar # Deletes file but leaves .git/logs/refs/heads/foo/
    git branch foo        # Deletes .git/logs/refs/heads/foo/

But the only reason the last command deletes the directory is because
it wants to create a file with the same name.  So if another process
(e.g.,

    git branch foo/baz

) wants to create that directory, one of the two is doomed to failure
anyway because of a D/F conflict.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-21 13:47:13 -08:00
Michael Haggerty
fa59ae7971 rename_ref(): extract function rename_tmp_log()
It's about to become a bit more complex.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-21 13:46:59 -08:00
Michael Haggerty
e5c223e98b lock_ref_sha1_basic(): if locking fails with ENOENT, retry
If hold_lock_file_for_update() fails with errno==ENOENT, it might be
because somebody else (for example, a pack-refs process) has just
deleted one of the lockfile's ancestor directories.  So if this
condition is detected, try again (up to 3 times).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-21 13:46:30 -08:00
Michael Haggerty
c4c61c763e lock_ref_sha1_basic(): on SCLD_VANISHED, retry
If safe_create_leading_directories() fails because a file along the
path unexpectedly vanished, try again (up to 3 times).

This can occur if another process is deleting directories at the same
time as we are trying to make them.  For example, "git pack-refs
--all" tries to delete the loose refs and any empty directories that
are left behind.  If a pack-refs process is running, then it might
delete a directory that we need to put a new loose reference in.

If safe_create_leading_directories() thinks this might have happened,
then take its advice and try again (maximum three attempts).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-21 13:46:07 -08:00
Michael Haggerty
54457fe509 refname_match(): always use the rules in ref_rev_parse_rules
We used to use two separate rules for the normal ref resolution
dwimming and dwimming done to decide which remote ref to grab.  The
third parameter to refname_match() selected which rules to use.

When these two rules were harmonized in

    2011-11-04 dd621df9cd refs DWIMmery: use the same rule for both "git fetch" and others

, ref_fetch_rules was #defined to avoid potential breakages for
in-flight topics.

It is now safe to remove the backwards-compatibility code, so remove
refname_match()'s third parameter, make ref_rev_parse_rules private to
refs.c, and remove ref_fetch_rules entirely.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-14 13:58:06 -08:00
Junio C Hamano
540cc75f38 Merge branch 'mh/shorten-unambigous-ref'
* mh/shorten-unambigous-ref:
  shorten_unambiguous_ref(): tighten up pointer arithmetic
  gen_scanf_fmt(): delete function and use snprintf() instead
  shorten_unambiguous_ref(): introduce a new local variable
2014-01-13 11:34:08 -08:00
Michael Haggerty
7902fe03f9 shorten_unambiguous_ref(): tighten up pointer arithmetic
As long as we're being pathologically stingy with mallocs, we might as
well do the math right and save 6 (!) bytes.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-09 15:02:36 -08:00
Michael Haggerty
4346663a14 gen_scanf_fmt(): delete function and use snprintf() instead
To replace "%.*s" with "%s", all we have to do is use snprintf()
to interpolate "%s" into the pattern.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-09 14:56:06 -08:00
Michael Haggerty
84d5633f98 shorten_unambiguous_ref(): introduce a new local variable
When filling the scanf_fmts array, use a separate variable to keep
track of the offset to avoid clobbering total_len (which we will need
in the next commit).

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-09 14:52:44 -08:00
Christian Couder
5955654823 replace {pre,suf}fixcmp() with {starts,ends}_with()
Leaving only the function definitions and declarations so that any
new topic in flight can still make use of the old functions, replace
existing uses of the prefixcmp() and suffixcmp() with new API
functions.

The change can be recreated by mechanically applying this:

    $ git grep -l -e prefixcmp -e suffixcmp -- \*.c |
      grep -v strbuf\\.c |
      xargs perl -pi -e '
        s|!prefixcmp\(|starts_with\(|g;
        s|prefixcmp\(|!starts_with\(|g;
        s|!suffixcmp\(|ends_with\(|g;
        s|suffixcmp\(|!ends_with\(|g;
      '

on the result of preparatory changes in this series.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-05 14:13:21 -08:00
Junio C Hamano
e0fd1e3841 Merge branch 'sb/refs-code-cleanup'
* sb/refs-code-cleanup:
  cache: remove unused function 'have_git_dir'
  refs: remove unused function invalidate_ref_cache
2013-11-01 07:38:58 -07:00
Junio C Hamano
149a8134a7 Merge branch 'jk/refs-c-squelch-gcc'
* jk/refs-c-squelch-gcc:
  silence gcc array-bounds warning
2013-10-30 12:11:04 -07:00
Stefan Beller
746593bdca refs: remove unused function invalidate_ref_cache
The function 'invalidate_ref_cache' was introduced in 79c7ca5 (2011-10-17,
invalidate_ref_cache(): rename function from invalidate_cached_refs())
by a rename and elevated to be publicly usable in 8be8bde (2011-10-17,
invalidate_ref_cache(): expose this function in the refs API)

However it is not used anymore, as 8bf90dc (2011-10-17, write_ref_sha1():
only invalidate the loose ref cache) and (much) later 506a760 (2013-04-22,
refs: change how packed refs are deleted) removed any calls to this
function. So it seems as if we don't need that function any more,
good bye!

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Acked-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-28 08:55:56 -07:00
Jeff King
a4165851e7 silence gcc array-bounds warning
In shorten_unambiguous_ref, we build and cache a reverse-map of the
rev-parse rules like this:

  static char **scanf_fmts;
  static int nr_rules;
  if (!nr_rules) {
	  for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
		  ... generate scanf_fmts ...
  }

where ref_rev_parse_rules is terminated with a NULL pointer.
Compiling with "gcc -O2 -Wall" does not cause any problems, but
compiling with "-O3 -Wall" generates:

  $ make CFLAGS='-O3 -Wall' refs.o
  refs.c: In function ‘shorten_unambiguous_ref’:
  refs.c:3379:29: warning: array subscript is above array bounds [-Warray-bounds]
     for (; ref_rev_parse_rules[nr_rules]; nr_rules++)

Curiously, we can silence this by explicitly nr_rules to 0
in the beginning of the loop, even though the compiler
should be able to tell that we follow this code path only
when nr_rules is already 0.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-24 15:41:56 -07:00
Ramsay Jones
ce1e846207 refs.c: spell NULL pointer as NULL
A call to update_ref_lock() passes '0' to the 'int *type_p' parameter.
Noticed by sparse.  ("Using plain integer as NULL pointer")

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2013-10-14 16:10:50 -07:00
Junio C Hamano
f406140baa Merge branch 'fc/at-head'
Instead of typing four capital letters "HEAD", you can say "@" now,
e.g. "git log @".

* fc/at-head:
  Add new @ shortcut for HEAD
  sha1-name: pass len argument to interpret_branch_name()
2013-09-20 12:38:10 -07:00
Junio C Hamano
9a86b89941 Merge branch 'bk/refs-multi-update'
Give "update-refs" a "--stdin" option to read multiple update
requests and perform them in an all-or-none fashion.

* bk/refs-multi-update:
  update-ref: add test cases covering --stdin signature
  update-ref: support multiple simultaneous updates
  refs: add update_refs for multiple simultaneous updates
  refs: add function to repack without multiple refs
  refs: factor delete_ref loose ref step into a helper
  refs: factor update_ref steps into helpers
  refs: report ref type from lock_any_ref_for_update
  reset: rename update_refs to reset_refs
2013-09-20 12:36:12 -07:00
Felipe Contreras
9ba89f484e Add new @ shortcut for HEAD
Typing 'HEAD' is tedious, especially when we can use '@' instead.

The reason for choosing '@' is that it follows naturally from the
ref@op syntax (e.g. HEAD@{u}), except we have no ref, and no
operation, and when we don't have those, it makes sens to assume
'HEAD'.

So now we can use 'git show @~1', and all that goody goodness.

Until now '@' was a valid name, but it conflicts with this idea, so
let's make it invalid. Probably very few people, if any, used this name.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-09-12 14:39:34 -07:00
Junio C Hamano
2233ad4534 Merge branch 'jc/push-cas'
Allow a safer "rewind of the remote tip" push than blind "--force",
by requiring that the overwritten remote ref to be unchanged since
the new history to replace it was prepared.

The machinery is more or less ready.  The "--force" option is again
the big red button to override any safety, thanks to J6t's sanity
(the original round allowed --lockref to defeat --force).

The logic to choose the default implemented here is fragile
(e.g. "git fetch" after seeing a failure will update the
remote-tracking branch and will make the next "push" pass,
defeating the safety pretty easily).  It is suitable only for the
simplest workflows, and it may hurt users more than it helps them.

* jc/push-cas:
  push: teach --force-with-lease to smart-http transport
  send-pack: fix parsing of --force-with-lease option
  t5540/5541: smart-http does not support "--force-with-lease"
  t5533: test "push --force-with-lease"
  push --force-with-lease: tie it all together
  push --force-with-lease: implement logic to populate old_sha1_expect[]
  remote.c: add command line option parser for "--force-with-lease"
  builtin/push.c: use OPT_BOOL, not OPT_BOOLEAN
  cache.h: move remote/connect API out of it
2013-09-09 14:30:29 -07:00
Brad King
98aee92d5c refs: add update_refs for multiple simultaneous updates
Add 'struct ref_update' to encode the information needed to update or
delete a ref (name, new sha1, optional old sha1, no-deref flag).  Add
function 'update_refs' accepting an array of updates to perform.  First
sort the input array to order locks consistently everywhere and reject
multiple updates to the same ref.  Then acquire locks on all refs with
verified old values.  Then update or delete all refs accordingly.  Fail
if any one lock cannot be obtained or any one old value does not match.

Though the refs themselves cannot be modified together in a single
atomic transaction, this function does enable some useful semantics.
For example, a caller may create a new branch starting from the head of
another branch and rewind the original branch at the same time.  This
transfers ownership of commits between branches without risk of losing
commits added to the original branch by a concurrent process, or risk of
a concurrent process creating the new branch first.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-09-04 11:10:28 -07:00
Brad King
61cee0dbac refs: add function to repack without multiple refs
Generalize repack_without_ref as repack_without_refs to support a list
of refs and implement the former in terms of the latter.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-09-04 11:09:55 -07:00
Brad King
2ddb5d170a refs: factor delete_ref loose ref step into a helper
Factor loose ref deletion into helper function delete_ref_loose to allow
later use elsewhere.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-09-04 11:09:09 -07:00
Brad King
4738a33338 refs: factor update_ref steps into helpers
Factor the lock and write steps and error handling into helper functions
update_ref_lock and update_ref_write to allow later use elsewhere.
Expose lock_any_ref_for_update's type_p to update_ref_lock callers.

While at it, drop "static" from the local "lock" variable as it is not
necessary to keep across invocations.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-09-04 11:08:36 -07:00
Felipe Contreras
cf99a761d3 sha1-name: pass len argument to interpret_branch_name()
This is useful to make sure we don't step outside the boundaries of what
we are interpreting at the moment. For example while interpreting
foobar@{u}~1, the job of interpret_branch_name() ends right before ~1,
but there's no way to figure that out inside the function, unless the
len argument is passed.

So let's do that.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-09-03 11:33:00 -07:00