When we fall back to a standard for_each_reflog_ent() after failing to find
the nth branch switch (or if we had a short reflog) with the call to
for_each_recent_reflog_ent(), we do not need to free the memory allocated
for our strbuf's since a strbuf_reset() will be performed in
grab_nth_branch_switch() before assigning to the entry.

Plus, the strbuf_release() negates the non-zero hint we initially gave to
strbuf_init() just above these lines.
Signed-off-by: NBrandon Casey <drafnel@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These allow you to say "git checkout @{-2}" to switch to the branch two
"branch switching" ago by pretending as if you typed the name of that
branch.  As it is likely that we will be introducing more short-hands to
write the name of a branch without writing it explicitly, rename the
functions from "nth_last_branch" to more generic "branch_name", to prepare
for different semantics.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

057e7138 (Warn use of "origin" when remotes/origin/HEAD is dangling,
2009-02-08) tried to warn dangling refs/remotes/origin/HEAD only when
"origin" was used to refer to it.  There was one corner case a symref is
expected to be dangling and this warning is unwarranted: HEAD in an empty
repository.

This squelches the warning for this special case.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The previous one squelched the diagnositic message we used to issue every
time we enumerated the refs and noticed a dangling ref.  This adds the
warning back to the place where the user actually attempts to use it.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When get_sha1_basic() is passed a buffer of len 0, it should not
check if buf[len-1] is a curly bracket.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We only accept "checkout: moving from A to B" newer style reflog entries,
in order to pick up A.  There is no point computing where B begins at
after running strstr to locate " to ", nor adding 4 and then subtracting 4
from the same pointer.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This can be used to scan only the last few kilobytes of a reflog, as a
cheap optimization when the data you are looking for is likely to be
found near the end of it.  The caller is expected to fall back to the
full scan if that is not the case.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

target can be NULL when we failed to parse the message.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

To do that, Git no longer looks forward for the '@{' corresponding to the
closing '}' but backward, and dwim_ref() as well as dwim_log() learnt
about the @{-<N>} notation.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

You can have quite a many reflog entries, but you typically won't recall
which branch you were on after switching branches for more than several
times.

Instead of reading the reflog twice, this reads the branch switching event
and keeps as many entries as the user asked from the latest such entries,
which is the minimum required to be able to switch back to the branch we
were recently on.

[jc: improvements from Dscho squashed in]
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Let get_sha1() parse the @{-N} syntax, with docs and tests.

Note that while @{-1}^2, @{-2}~5 and such are supported, @{-1}@{1} is
currently not allowed.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Have the lookup only look at "interesting" checkouts, meaning those
that tell you "Already on ..." don't count even though they also cause
a reflog entry.

Let interpret_nth_last_branch() return the number of characters
parsed, so that git-checkout can verify that the branch spec was
@{-N}, not @{-1}^2 or something like that.  (The latter will be added
later.)
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Implement a shortcut @{-N} for the N-th last branch checked out, that
works by parsing the reflog for the message added by previous
git-checkout invocations.  We expand the @{-N} to the branch name, so
that you end up on an attached HEAD on that branch.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Otherwise the function sometimes fail to resolve obviously correct
refnames, because the string data pointed to by "str" argument were
reused.

The change in dwim_log does not fix anything, just optimizes away
strcpy code as the path can be created directly in the available
buffer.
Signed-off-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

As we support seconds-since-epoch in $GIT_COMMITTER_TIME we should
also support it in a reflog @{...} style notation.  We can easily
tell this part from @{nth} style notation by looking to see if the
value is unreasonably large for an @{nth} style notation.

The value 100000000 was chosen as it is already used by date.c to
disambiguate yyyymmdd format from a seconds-since-epoch time value.

A reflog with 100,000,000 record entries is also simply not valid.
Such a reflog would require at least 7.7 GB to store just the old
and new SHA-1 values.  So our randomly chosen upper limit for @{nth}
notation is "big enough".
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

f2eba66d (Enable HEAD@{...} and make it independent from the current
branch, 2007-02-03) introduced dwim_log() to handle <refname>@{...}
syntax, and as part of its processing, it checks if the ref exists by
calling refsolve_ref().  It should call it as a reader to make sure the
call returns NULL for a nonexistent ref (not as a potential writer in
which case it does not return NULL).
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In get_sha1_basic, we parse a string like

  HEAD@{10 seconds ago}:path/to/file

into its constituent ref, reflog date, and path components.
We never actually munge the string itself, but instead keep
offsets into the string with their associated lengths.

When we call approxidate on the contents inside braces,
however, we pass just a string without a length. This means
that approxidate could sometimes look past the closing brace
and (erroneously) interpret the rest of the string as part
of the date.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

I think it would make more sense for rev~ to have the same guarantees that
rev^ has, namely to always return a commit. I would also suggest that not
giving a number would have the same effect of defaulting to 1, not 0.

Right now it's a bit illogical, but at least it's an _undocumented_
illogical behaviour.

This patch makes '^' and '~' act the same for the default count (i.e. both
default to 1), and also have the same behaviour for a count of zero.

Before (no discernible pattern):

	[torvalds@woody git]$ git rev-parse v1.5.1 v1.5.1^0 v1.5.1~0 v1.5.1^ v1.5.1~
	45354a57ee7e3e42c7137db6c94fa968c6babe8d
	89815cab
	45354a57ee7e3e42c7137db6c94fa968c6babe8d
	045f5759
	45354a57ee7e3e42c7137db6c94fa968c6babe8d

After (fairly logical):

	[torvalds@woody git]$ git rev-parse v1.5.1 v1.5.1^0 v1.5.1~0 v1.5.1^ v1.5.1~
	45354a57ee7e3e42c7137db6c94fa968c6babe8d
	89815cab
	89815cab
	045f5759
	045f5759Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The function returned NULL when no object that matches the name
was found, but that made the callers more complicated, as nobody
used that NULL return as an indication that no object with such
a name exists.  They (at least the careful ones) instead took
the full 40-hexdigit and used in such a case, and the careless
ones segfaulted.

With this "git rev-parse --short 5555555555555555555555555555555555555555"
would stop segfaulting.

This is based on Jeff King's rewrite to my RFC patch, but "missing"
logic swapped to "exists".  The final logic reads:

    For existing objects, make sure the abbreviated string uniquely
    identifies it.  Otherwise, make sure the abbreviated string is
    long enough so that it would not name any existing object.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This change removes all obvious useless if-before-free tests.
E.g., it replaces code like this:

        if (some_expression)
                free (some_expression);

with the now-equivalent:

        free (some_expression);

It is equivalent not just because POSIX has required free(NULL)
to work for a long time, but simply because it has worked for
so long that no reasonable porting target fails the test.
Here's some evidence from nearly 1.5 years ago:

    http://www.winehq.org/pipermail/wine-patches/2006-October/031544.html

FYI, the change below was prepared by running the following:

  git ls-files -z | xargs -0 \
  perl -0x3b -pi -e \
    's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)\s+(free\s*\(\s*\1\s*\))/$2/s'

Note however, that it doesn't handle brace-enclosed blocks like
"if (x) { free (x); }".  But that's ok, since there were none like
that in git sources.

Beware: if you do use the above snippet, note that it can
produce syntactically invalid C code.  That happens when the
affected "if"-statement has a matching "else".
E.g., it would transform this

  if (x)
    free (x);
  else
    foo ();

into this:

  free (x);
  else
    foo ();

There were none of those here, either.

If you're interested in automating detection of the useless
tests, you might like the useless-if-before-free script in gnulib:
[it *does* detect brace-enclosed free statements, and has a --name=S
 option to make it detect free-like functions with different names]

  http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=build-aux/useless-if-before-free

Addendum:
  Remove one more (in imap-send.c), spotted by Jean-Luc Herren <jlh@gmx.ch>.
Signed-off-by: NJim Meyering <meyering@redhat.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMartin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMartin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This helper function is the core of "$object^{type}" parser.
Now it is made available to callers outside sha1_name.c

Signed-off-by: NMartin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This converts the index explicitly on read and write to its on-disk
format, allowing the in-core format to contain more flags, and be
simpler.

In particular, the in-core format is now host-endian (as opposed to the
on-disk one that is network endian in order to be able to be shared
across machines) and as a result we can dispense with all the
htonl/ntohl on accesses to the cache_entry fields.

This will make it easier to make use of various temporary flags that do
not exist in the on-disk format.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Earlier, ':/<oneline-prefix>' would not work (i.e. die) with commands that
set save_commit_buffer = 0, such as blame, describe, pack-objects, reflog
and bundle.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We use at least two rulesets for matching abbreviated refnames with
full refnames (starting with 'refs/').  git-rev-parse and git-fetch
use slightly different rules.

This commit introduces a new function refname_match
(const char *abbrev_name, const char *full_name, const char **rules).

abbrev_name is expanded using the rules and matched against full_name.
If a match is found the function returns true.  rules is a NULL-terminate
list of format patterns with "%.*s", for example:

    const char *ref_rev_parse_rules[] = {
               "%.*s",
               "refs/%.*s",
               "refs/tags/%.*s",
               "refs/heads/%.*s",
               "refs/remotes/%.*s",
               "refs/remotes/%.*s/HEAD",
               NULL
    };

Asterisks are included in the format strings because this is the form
required in sha1_name.c.  Sharing the list with the functions there is
a good idea to avoid duplicating the rules.  Hopefully this
facilitates unified matching rules in the future.

This commit makes the rules used by rev-parse for resolving refs to
sha1s available for string comparison.  Before this change, the rules
were buried in get_sha1*() and dwim_ref().

A follow-up commit will refactor the rules used by fetch.

refname_match() will be used for matching refspecs in git-send-pack.

Thanks to Daniel Barkalow <barkalow@iabervon.org> for pointing
out that ref_matches_abbrev in remote.c solves a similar problem
and care should be taken to avoid confusion.
Signed-off-by: NSteffen Prohaska <prohaska@zib.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These days, show_date() takes a date_mode parameter to specify
the output format, and a separate specialized function for dates
in E-mails does not make much sense anymore.

This retires show_rfc2822_date() function and make it just
another date output format.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

find_short_packed_object was not loading the pack index files.
Teach it to do so.
Signed-off-by: NJames Bowes <jbowes@dangerouslyinc.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Not every input value passed to get_sha1 is an abbreviated SHA-1.
Its actually quite common for refs to be passed and for those
refs to resolve to full SHA-1s, in which case we may not need to
initialize the alternate object database list in this process.

I'm relocating the call to prepare_alt_odb closer to the code
that actually needs it to maintain the fix first introduced by
Junio in 99a19b43 (to avoid ambiguous SHA-1 abbreviations from
being accepted).  This allows us to avoid the alt_odb list setup
if we won't actually need it.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

get_sha1_with_mode basically behaves as get_sha1. It has an additional
parameter for storing the mode of the object.

If the mode can not be determined, it stores S_IFINVALID.
Signed-off-by: NMartin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The coming index format change doesn't allow for the number of objects
to be determined from the size of the index file directly.  Instead, Let's
initialize a field in the packed_git structure with the object count when
the index is validated since the count is always known at that point.

While at it let's reorder some struct packed_git fields to avoid padding
due to needed 64-bit alignment for some of them.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Let's avoid the open coded pack index reference in pack-object and use
nth_packed_object_sha1() instead.  This will help encapsulating index
format differences in one place.

And while at it there is no reason to copy SHA1's over and over while a
direct pointer to it in the index will do just fine.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Acked-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

What the function wants to return is not if we saw any return
from pop_most_recent_commit(), but if we found what was asked
for.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

a try, but all I could get was a segfault.  It was dereferencing a NULL
commit list.  Fix below.  With it, this example now works:

    $ mkdir .j; cd .j; touch f
    $ git-init; git-add f; git-commit -mc f; echo x >f; git-commit -md f
    $ git-diff -p :/c :/d
    diff --git a/f b/f
    index e69de29..587be6b 100644
    --- a/f
    +++ b/f
    @@ -0,0 +1 @@
    +x
Signed-off-by: NJim Meyering <jim@meyering.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

As we permit up to 2^32-1 objects in a single packfile we cannot
use a signed int to represent the object offset within a packfile,
after 2^31-1 objects we will start seeing negative indexes and
error out or compute bad addresses within the mmap'd index.

This is a minor cleanup that does not introduce any significant
logic changes.  It is roach free.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

To name a commit, you can now say

	$ git rev-parse ':/Initial revision of "git"'

and it will return the hash of the youngest commit whose
commit message (the oneline) begins with the given prefix.

For future extension, a leading exclamation mark is treated
specially: if you want to match a commit message starting with
a '!', just repeat the exclamation mark. So, to match a commit
which starts with '!Hello World', use

	$ git show ':/!!Hello World'
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When refs/remotes/gfi/master and refs/remotes/gfi/HEAD exist,
and the latter is a symref that points at the former, dwim_ref()
resolves string "gfi" to "refs/remotes/gfi/master" as expected,
but dwim_log() does not understand "gfi@{1.day}" and needs to be
told "gfi/master@{1.day}".  This is confusing.
Signed-off-by: NJunio C Hamano <junkio@cox.net>