This also adds some very rudimentary support for the notion of packed
refs.  HOWEVER! At this point it isn't used to actually look up a ref
yet, only for listing them (ie "for_each_ref()" and friends see the
packed refs, but none of the other single-ref lookup routines).

Note how we keep two separate lists: one for the loose refs, and one for
the packed refs we read. That's so that we can easily keep the two apart,
and read only one set or the other (and still always make sure that the
loose refs take precedence).

[ From this, it's not actually obvious why we'd keep the two separate
  lists, but it's important to have the packed refs on their own list
  later on, when I add support for looking up a single loose one.

  For that case, we will want to read _just_ the packed refs in case the
  single-ref lookup fails, yet we may end up needing the other list at
  some point in the future, so keeping them separated is important ]
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Like xmalloc and xrealloc xstrdup dies with a useful message if
the native strdup() implementation returns NULL rather than a
valid pointer.

I just tried to use xstrdup in new code and found it to be missing.
However I expected it to be present as xmalloc and xrealloc are
already commonly used throughout the code.

[jc: removed the part that deals with last_XXX, which I am
 finding more and more dubious these days.]
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Jonas noticed some places say "if (X) free(X)" which is totally
unnecessary.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This abstracts away the size of the hash values when copying them
from memory location to memory location, much as the introduction
of hashcmp abstracted away hash value comparsion.

A few call sites were using char* rather than unsigned char* so
I added the cast rather than open hashcpy to be void*.  This is a
reasonable tradeoff as most call sites already use unsigned char*
and the existing hashcmp is also declared to be unsigned char*.

[jc: Splitted the patch to "master" part, to be followed by a
 patch for merge-recursive.c which is not in "master" yet.

 Fixed the cast in the latter hunk to combine-diff.c which was
 wrong in the original.

 Also converted ones left-over in combine-diff.c, diff-lib.c and
 upload-pack.c ]
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Introduces global inline:

	hashcmp(const unsigned char *sha1, const unsigned char *sha2)

Uses memcmp for comparison and returns the result based on the length of
the hash name (a future runtime decision).
Acked-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Most of the callers except the one in refs.c use the function to
update the index file.  Among the index writers, everybody
except write-tree dies if they cannot open it for writing.

This gives the function an extra argument, to tell it to die
when it cannot create a new file as the lockfile.

The only caller that does not have to die is write-tree, because
updating the index for the cache-tree part is optional and not
being able to do so does not affect the correctness.  I think we
do not have to be so careful and make the failure into die() the
same way as other callers, but that would be a different patch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

As Fredrik points out the current interface of has_extension() is
potentially confusing.  Its parameters include both a nul-terminated
string and a length-limited string.

This patch drops the length argument, requiring two nul-terminated
strings; all callsites are updated.  I checked that all of them indeed
provide nul-terminated strings.  Filenames need to be nul-terminated
anyway if they are to be passed to open() etc.  The performance penalty
of the additional strlen() is negligible compared to the system calls
which inevitably surround has_extension() calls.

Additionally, change has_extension() to use size_t inside instead of
int, as that is the exact type strlen() returns and memcmp() expects.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The little helper has_extension() documents through its name what we are
trying to do and makes sure we don't forget the underrun check.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Alex Riesen (raa.lkml@gmail.com) recently observed that git branch
would fail with no error message due to unexpected situations with
regards to refs.  For example, if .git/refs/heads/gu is a file but
"git branch -b refs/heads/gu/fixa HEAD" was invoked by the user
it would fail silently due to refs/heads/gu being a file and not
a directory.

This change adds a test for trying to create a ref within a directory
that is actually currently a file, and adds error printing within
the ref locking routine should the resolve operation fail.

The error printing code probably belongs at this level of the library
as other failures within the ref locking, writing and logging code
are also currently at this level of the code.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Apparently calling setup_ident() after git_config causes the
user.name and user.email values read from the config file to be
replaced with the data obtained from the host.  This means that
users who have setup their email address in user.email will instead
be writing reflog entries with their hostname.

Moving setup_ident() to before git_config in update-ref resolves
this ordering problem.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NAlp Toker <alp@atoker.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

There were a few calls to adjust_shared_perm() that were
missing:

 - init-db creates refs, refs/heads, and refs/tags before
   reading from templates that could specify sharedrepository in
   the config file;

 - updating config file created it under user's umask without
   adjusting;

 - updating refs created it under user's umask without
   adjusting;

 - switching branches created .git/HEAD under user's umask
   without adjusting.

This moves adjust_shared_perm() from sha1_file.c to path.c,
since a few SIMPLE_PROGRAM need to call repository configuration
functions which in turn need to call adjust_shared_perm().
sha1_file.c needs to link with SHA1 computation library which
is usually not linked to SIMPLE_PROGRAM.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

A few style fixes to get the code in line with the rest.

 - asterisk to make a type a pointer to something goes in front
   of the variable, not at the end of the base type.
   E.g. a pointer to an integer is "int *ip", not "int* ip".

 - open parenthesis for function parameter list, unlike
   syntactic constructs, comes immediately after the function
   name.  E.g. "if (foo) bar();" not "if(foo) bar ();".

 - "else" does not come on the same line as the closing brace of
   corresponding "if".

The style is mostly a matter of personal taste, and people may
disagree, but consistency is important.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This updates the ref locking code to use creat-rename locking
code we use for the index file, so that it can borrow the code
to clean things up upon signals and program termination.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

My earlier attempt at forcing a write for non-existant refs worked;
it forced a write for pretty much all refs.  This corrects the
condition to only force a write for refs which don't exist yet.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

If a ref is changed by http-fetch, local-fetch or ssh-fetch
record the change and the remote URL/name in the log for the ref.
This requires loading the config file to check logAllRefUpdates.

Also fixed a bug in the ref lock generation; the log file name was
not being produced right due to a bad prefix length.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Normally we try to skip writing a ref if its value hasn't changed
but in the special case that the ref doesn't exist but the new
value is going to be 0{40} then force writing the ref anyway.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Corrected the log starting time displayed in the error message
(as it was always showing the epoch due to a bad input to strtoul).

Improved the log parser so we only scan backwards towards the
'\n' from the end of the prior log; during this scan the last '>'
is remembered to improve performance (rather than scanning forward
to it).

If the log record matched is the last log record in the file only
use its new sha1 value if the date matches exactly; otherwise we
leave the passed in sha1 alone as it already contains the current
value of the ref.  This way lookups of dates later than the log
end to stick with the current ref value in case the ref was updated
without logging.

If it looks like someone changed the ref without logging it and we
are going to return the sha1 which should have been valid during
the missing period then warn the user that there might be log data
missing and thus their query result may not be accurate.  The check
isn't perfect as its just based on comparing the old and new sha1
values between the two log records but its better than not checking
at all.

Implemented test cases based on git-rev-parse for most of the
boundary conditions.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The log parser was only ever matching the last log record due to
calling strtoul on "> 1136091609" rather than " 1136091609".  Also
once a match for '@' has been found after the name of the ref there
is no point in looking for another '@' within the remaining text.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Extended sha1 expressions may now include date specifications
which indicate a point in time within the local repository's
history.  If the ref indicated to the left of '@' has a log in
$GIT_DIR/logs/<ref> then the value of the ref at the time indicated
by the specification is obtained from the ref's log.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

If config parameter core.logAllRefUpdates is true or the log
file already exists then append a line to ".git/logs/refs/<ref>"
whenever git-update-ref <ref> is executed.  Each log line contains
the following information:

  oldsha1 <SP> newsha1 <SP> committer <LF>

where committer is the current user, date, time and timezone in
the standard GIT ident format.  If the caller is unable to append
to the log file then git-update-ref will fail without updating <ref>.

An optional message may be included in the log line with the -m flag.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Created 'struct ref_lock' to contain the data necessary to perform
a ref update.  This change improves writing a ref as the file names
are generated only once (rather than twice) and supports following
symrefs (up to the maximum depth).  Further the ref_lock structure
provides room to extend the update API with ref logging.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

"git branch" uses "rev-parse --all" and becomes much too slow when
there are many tags (it scans all refs).  Use the new "--branches"
option of rev-parse to speed things up.
Signed-off-by: NSean Estabrooks <seanlkml@sympatico.ca>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When inspecting a project whose build infrastructure used to
assume that .git/HEAD is a symlink ref, core.prefersymlinkrefs
in the config file of such a project would help to bisect its
history.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
(cherry picked from 9f0bb90d commit)

When inspecting a project whose build infrastructure used to
assume that .git/HEAD is a symlink ref, core.prefersymlinkrefs
in the config file of such a project would help to bisect its
history.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

We used fprintf() to show an error message without terminating
it with LF; use error() for that.

cf. c401cb48Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

Disable USE_SYMLINK_HEAD by default.  Recommend using it only for
compatibility with older software.

Treat USE_SYMLINK_HEAD like other optional defines - check whether it's
defined, not its value.
Signed-off-by: NPavel Roskin <proski@gnu.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This reverts ee34518d commit.

This reverts 06bf6ac4 commit.

by marking '?', '*', and '[' as bad_ref_char().
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

This makes git-check-ref-format fail for "HEAD". Since the check is only
executed when creating refs, the existing symbolic ref is safe.

Otherwise these commands, most likely are pilot errors, would do
pretty funky stuff:

	git checkout -b HEAD
	git pull . other:HEAD
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Otherwise cloning a repository with hierarchical branch/tag
over http would fail.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This should force git-daemon administrator's job a bit harder
because the exact paths need to be given in the whitelist, but
at the same time makes the auditing easier.

This moves validate_symref() from refs.c to path.c, because we
need to link path.c with git-daemon for its "enter_repo()", but
we do not want to link the daemon with the rest of git libraries
and its requirements.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJunio C Hamano <junkio@cox.net>

This allows you to force git to avoid symlinks for refs. Just add
something like

	[core]
		symrefsonly = true

to .git/config.

Don´t forget to "git checkout your_branch", or it does not do anything...
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

There are filesystems out there which do not understand symlinks, even if
the OS is perfectly capable of writing them. So, do not fail right away,
but try to write a symbolic ref first. If that fails, you can die().
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>