Convert this function to use struct object_id.  Express several
hardcoded constants in terms of GIT_SHA1_HEXSZ.
Signed-off-by: Nbrian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: NJeff King <peff@peff.net>

Use struct object_id in three fields in struct ref and convert all the
necessary places that use it.
Signed-off-by: Nbrian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: NJeff King <peff@peff.net>

This patch puts the usage info strings that were not already in docopt-
like format into docopt-like format, which will be a litle easier for
end users and a lot easier for translators. Changes include:

- Placing angle brackets around fill-in-the-blank parameters
- Putting dashes in multiword parameter names
- Adding spaces to [-f|--foobar] to make [-f | --foobar]
- Replacing <foobar>* with [<foobar>...]
Signed-off-by: NAlex Henrie <alexhenrie24@gmail.com>
Reviewed-by: NMatthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Cloning from a shallow repository does not follow the "8 steps for new
.git/shallow" because if it does we need to get through step 6 for all
refs. That means commit walking down to the bottom.

Instead the rule to create .git/shallow is simpler and, more
importantly, cheap: if a shallow commit is found in the pack, it's
probably used (i.e. reachable from some refs), so we add it. Others
are dropped.

One may notice this method seems flawed by the word "probably". A
shallow commit may not be reachable from any refs at all if it's
attached to an object island (a group of objects that are not
reachable by any refs).

If that object island is not complete, a new fetch request may send
more objects to connect it to some ref. At that time, because we
incorrectly installed the shallow commit in this island, the user will
not see anything after that commit (fsck is still ok). This is not
desired.

Given that object islands are rare (C Git never sends such islands for
security reasons) and do not really harm the repository integrity, a
tradeoff is made to surprise the user occasionally but work faster
everyday.

A new option --strict could be added later that follows exactly the 8
steps. "git prune" can also learn to remove dangling objects _and_ the
shallow commits that are attached to them from .git/shallow.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

No callers pass a non-empty pointer as shallow_points at this
stage. As a result, all clients still refuse to talk to shallow
repository on the other end.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The main purpose is to trace the URL parser called by git_connect() in
connect.c

The main features of the parser can be listed as this:

- parse out host and path for URLs with a scheme (git:// file:// ssh://)
- parse host names embedded by [] correctly
- extract the port number, if present
- separate URLs like "file" (which are local)
  from URLs like "host:repo" which should use ssh

Add the new parameter "--diag-url" to "git fetch-pack", which prints
the value for protocol, host and path to stderr and exits.
Signed-off-by: NTorsten Bögershausen <tboegi@web.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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: NChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is an extension of c6807a40 (clone: open a shortcut for
connectivity check - 2013-05-26) to reduce the cost of connectivity
check at clone time, this time with smart http protocol.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The definition of "struct ref" in "cache.h", a header file so
central to the system, always confused me.  This structure is not
about the local ref used by sha1-name API to name local objects.

It is what refspecs are expanded into, after finding out what refs
the other side has, to define what refs are updated after object
transfer succeeds to what values.  It belongs to "remote.h" together
with "struct refspec".

While we are at it, also move the types and functions related to the
Git transport connection to a new header file connect.h
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Now that we can read packet data from memory as easily as a
descriptor, get_remote_heads can take either one as a
source. This will allow further refactoring in remote-curl.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Most of the callers of packet_read_line just read into a
static 1000-byte buffer (callers which handle arbitrary
binary data already use LARGE_PACKET_MAX). This works fine
in practice, because:

  1. The only variable-sized data in these lines is a ref
     name, and refs tend to be a lot shorter than 1000
     characters.

  2. When sending ref lines, git-core always limits itself
     to 1000 byte packets.

However, the only limit given in the protocol specification
in Documentation/technical/protocol-common.txt is
LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in
pack-protocol.txt, and then only describing what we write,
not as a specific limit for readers.

This patch lets us bump the 1000-byte limit to
LARGE_PACKET_MAX. Even though git-core will never write a
packet where this makes a difference, there are two good
reasons to do this:

  1. Other git implementations may have followed
     protocol-common.txt and used a larger maximum size. We
     don't bump into it in practice because it would involve
     very long ref names.

  2. We may want to increase the 1000-byte limit one day.
     Since packets are transferred before any capabilities,
     it's difficult to do this in a backwards-compatible
     way. But if we bump the size of buffer the readers can
     handle, eventually older versions of git will be
     obsolete enough that we can justify bumping the
     writers, as well. We don't have plans to do this
     anytime soon, but there is no reason not to start the
     clock ticking now.

Just bumping all of the reading bufs to LARGE_PACKET_MAX
would waste memory. Instead, since most readers just read
into a temporary buffer anyway, let's provide a single
static buffer that all callers can use. We can further wrap
this detail away by having the packet_read_line wrapper just
use the buffer transparently and return a pointer to the
static storage.  That covers most of the cases, and the
remaining ones already read into their own LARGE_PACKET_MAX
buffers.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The packets sent during ref negotiation are all terminated
by newline; even though the code to chomp these newlines is
short, we end up doing it in a lot of places.

This patch teaches packet_read_line to auto-chomp the
trailing newline; this lets us get rid of a lot of inline
chomping code.

As a result, some call-sites which are not reading
line-oriented data (e.g., when reading chunks of packfiles
alongside sideband) transition away from packet_read_line to
the generic packet_read interface. This patch converts all
of the existing callsites.

Since the function signature of packet_read_line does not
change (but its behavior does), there is a possibility of
new callsites being introduced in later commits, silently
introducing an incompatibility.  However, since a later
patch in this series will change the signature, such a
commit would have to be merged directly into this commit,
not to the tip of the series; we can therefore ignore the
issue.

This is an internal cleanup and should produce no change of
behavior in the normal case. However, there is one corner
case to note. Callers of packet_read_line have never been
able to tell the difference between a flush packet ("0000")
and an empty packet ("0004"), as both cause packet_read_line
to return a length of 0. Readers treat them identically,
even though Documentation/technical/protocol-common.txt says
we must not; it also says that implementations should not
send an empty pkt-line.

By stripping out the newline before the result gets to the
caller, we will now treat the newline-only packet ("0005\n")
the same as an empty packet, which in turn gets treated like
a flush packet. In practice this doesn't matter, as neither
empty nor newline-only packets are part of git's protocols
(at least not for the line-oriented bits, and readers who
are not expecting line-oriented packets will be calling
packet_read directly, anyway). But even if we do decide to
care about the distinction later, it is orthogonal to this
patch.  The right place to tighten would be to stop treating
empty packets as flush packets, and this change does not
make doing so any harder.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Even though "git fetch" has full infrastructure to parse refspecs to
be fetched and match them against the list of refs to come up with
the final list of refs to be fetched, the list of refs that are
requested to be fetched were internally converted to a plain list of
strings at the transport layer and then passed to the underlying
fetch-pack driver.

Stop this conversion and instead pass around an array of refs.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we look up a sha1 object for reading via parse_object() =>
read_sha1_file() => read_object() callpath, we first check
packfiles, and then loose objects. If we still haven't found it, we
re-scan the list of packfiles in `objects/pack`. This final step
ensures that we can co-exist with a simultaneous repack process
which creates a new pack and then prunes the old object.

This extra re-scan usually does not have a performance impact for
two reasons:

  1. If an object is missing, then typically the re-scan will find a
     new pack, then no more misses will occur.  Or if it truly is
     missing, then our next step is usually to die().

  2. Re-scanning is cheap enough that we do not even notice.

However, these do not always hold. The assumption in (1) is that the
caller is expecting to find the object. This is usually the case,
but the call to `parse_object` in `everything_local` does not follow
this pattern. It is looking to see whether we have objects that the
remote side is advertising, not something we expect to
have. Therefore if we are fetching from a remote which has many refs
pointing to objects we do not have, we may end up re-scanning the
pack directory many times.

Even with this extra re-scanning, the impact is often not noticeable
due to (2); we just readdir() the packs directory and skip any packs
that are already loaded. However, if there are a large number of
packs, even enumerating the directory can be expensive, especially
if we do it repeatedly.

Having this many packs is a good sign the user should run `git gc`,
but it would still be nice to avoid having to scan the directory at
all.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

lock is only used by fetch_pack, so move it into that function.
Signed-off-by: NMatt Kraai <matt.kraai@amo.abbott.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

fetch_pack() is used by transport.c, part of libgit.a while it stays
in builtin/fetch-pack.c. Move it to fetch-pack.c so that we won't get
undefined reference if a program that uses libgit.a happens to pull it
in.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJeff King <peff@peff.net>

This helps removes the hack in fetch_pack() that copies my_args to args.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJeff King <peff@peff.net>

It used to be that if "--all", "--depth", and also explicit references
were sought, then the explicit references were not handled correctly
in filter_refs() because the "--all --depth" code took precedence over
the explicit reference handling, and the explicit references were
never noted as having been found.  So check for explicitly sought
references before proceeding to the "--all --depth" logic.

This fixes two test cases in t5500.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Set the final value at initialization rather than initializing it then
sometimes changing it.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This fixes a test in t5500.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This simplifies the logic without changing the behavior.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Simplify flow within loop: first decide whether to keep the reference,
then keep/free it.  This makes it clearer that each ref has exactly
two possible destinies, and removes duplication of the code for
appending the reference to the linked list.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Instead of temporarily storing matched refs to temporary array
"return_refs", simply append them to newlist as we go.  This changes
the order of references in newlist to strictly sorted if "--all" and
"--depth" and named references are all specified, but that usage is
broken anyway (see the last two tests in t5500).

This changes the last test in t5500 from segfaulting into just
emitting a spurious error (this will be fixed in a moment).
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Remove any references that are available from the remote from the
sought list (rather than overwriting their names with NUL characters,
as previously).  Mark matching entries by writing a non-NULL pointer
to string_list_item::util during the iteration, then use
filter_string_list() later to filter out the entries that have been
marked.

Document this aspect of fetch_pack() in a comment in the header file.
(More documentation is obviously still needed.)
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

fetch_pack() removes duplicates from the "sought" list, thereby
shrinking the list.  But previously, the caller was not informed about
the shrinkage.  This would cause a spurious error message to be
emitted by cmd_fetch_pack() if "git fetch-pack" is called with
duplicate refnames.

Instead, remove duplicates using string_list_remove_duplicates(),
which adjusts sought->nr to reflect the new length of the list.

The last test of t5500 inexplicably *required* "git fetch-pack" to
fail when fetching a list of references that contains duplicates;
i.e., it insisted on the buggy behavior.  So change the test to expect
the correct behavior.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Once a match has been found at sought_pos, the entry is zeroed and no
future attempts will match that entry.  So increment sought_pos to
avoid checking against the zeroed-out entry during the next iteration.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Instead of juggling <nr_heads,heads> (sometimes called
<nr_match,match>), pass around the list of references to be sought in
a single string_list variable called "sought".  Future commits will
make more use of string_list functionality.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fetch-pack's verbose mode is more of a debugging mode (and
in fact takes two "-v" arguments to trigger via the
porcelain layer). Let's mention the server version as
another possible item of interest.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In the same spirit as the previous fix, stop asking for thin-pack, no-progress
and include-tag capabilities when the other end does not claim to support them.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commit ff5effdf taught both clients and servers of the git protocol
to send an "agent" capability that just advertises their version for
statistics and debugging purposes.  The protocol-capabilities.txt
document however indicates that the client's advertisement is
actually a response, and should never include capabilities not
mentioned in the server's advertisement.

Adding the unconditional advertisement in the server programs was
OK, then, but the clients broke the protocol.  The server
implementation of git-core itself does not care, but at least one
does: the Google Code git server (or any server using Dulwich), will
hang up with an internal error upon seeing an unknown capability.

Instead, each client must record whether we saw an agent string from
the server, and respond with its agent only if the server mentioned
it first.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Instead of having the client advertise a particular version
number in the git protocol, we have managed extensions and
backwards compatibility by having clients and servers
advertise capabilities that they support. This is far more
robust than having each side consult a table of
known versions, and provides sufficient information for the
protocol interaction to complete.

However, it does not allow servers to keep statistics on
which client versions are being used. This information is
not necessary to complete the network request (the
capabilities provide enough information for that), but it
may be helpful to conduct a general survey of client
versions in use.

We already send the client version in the user-agent header
for http requests; adding it here allows us to gather
similar statistics for non-http requests.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commit 44359685 started sorting heads fed to fetch-pack so
that later commits could use more optimized algorithms;
commit 7db8d537 switched the remove_duplicates function to
such an algorithm.

Of course, the sorting is more effective if you do it
_before_ the algorithm in question.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We have a list of refs that we want to compare against the
"match" array. The current code searches the match list
linearly, giving quadratic behavior over the number of refs
when you want to fetch all of them.

Instead, we can compare the lists as we go, giving us linear
behavior.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Having the list sorted means we can avoid some quadratic
algorithms when comparing lists.

These should typically be sorted already, but they do come
from the remote, so let's be extra careful. Our ref-sorting
implementation does a mergesort, so we do not have to care
about performance degrading in the common case that the list
is already sorted.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We remove duplicate entries from the list of refs we are
fed in fetch-pack. The original algorithm is quadratic over
the number of refs, but since the list is now guaranteed to
be sorted, we can do it in linear time.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There's no reason to preserve the incoming order of the
heads we're requested to fetch. By having them sorted, we
can replace some of the quadratic algorithms with linear
ones.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The old code cast away the constness of the strings passed to the
function in argument argv[], which could result in their being
modified by filter_refs().  Fix by copying reference names from argv
and putting them into our own array (similarly to how refnames passed
to stdin were already handled).
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>