Like git-receive-pack, this is only partway done.

It's not working yet, but it's at the point where I want to be able to
track my changes.  The theory of operation is that this is the "remote"
side of a "git push".  It can tell us what references the remote side
has, receives out reference update commands and a pack-file, and can
execute the unpacking command.

Given a list of <pack>.idx files, this command validates the
index file and the corresponding .pack file for consistency.

This patch also uses the same validation mechanism in fsck-cache
when the --full flag is used.

During normal operation, sha1_file.c verifies that a given .idx
file matches the .pack file by comparing the SHA1 checksum
stored in .idx file and .pack file as a minimum sanity check.
We may further want to check the pack signature and version when
we map the pack, but that would be a separate patch.

Earlier, errors to map a pack file was not flagged fatal but led
to a random fatal error later.  This version explicitly die()s
when such an error is detected.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This makes it match the new delta encoding, and admittedly makes the
code easier to follow.

This also updates the PACK file version to 2, since this (and the delta
encoding change in the previous commit) are incompatible with the old
format.

Packed delta files created by git-pack-objects seems to be the
way to go, and existing "delta" object handling code has exposed
the object representation details to too many places.  Remove it
while we refactor code to come up with a proper interface in
sha1_file.c.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We want to be able to check their integrity later, and putting the
sha1-sum of the contents at the end is a good thing.  The writing
routines are generic, so we could try to re-use them for the index file,
instead of having the same logic duplicated.

Update unpack-objects to know about the extra 20 bytes at the end
of the index.

This will scan 2 or more object repositories and look for common objects, check
if they are hardlinked, and replace one with a hardlink to the other if not.

This version warns when skipping files because of size differences, and
handle more than 2 repositories automatically.
Signed-off-by: NRyan Anderson <ryan@michonline.com>
Cheered-on-by: NJeff Garzik <jgarzik@pobox.com>
Acked-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Using git-cherry, forward port local commits missing from the
new upstream head.  This also depends on "-m" flag support in
git-commit-script.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The git-cherry command helps the git-rebase script by finding
commits that have not been merged upstream.  Commits already
included in upstream are prefixed with '-' (meaning "drop from
my local pull"), while commits missing from upstream are
prefixed with '+' (meaning "add to the updated upstream").
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

So far it just reads the header and generates the list of objects.

It also sorts them by the order they are written in the pack file,
since that ends up being the same order we got them originally, and
is thus "most recent first".

This is kind of like a tar-ball for a set of objects, ready to be
shipped off to another end.  Alternatively, you could use is as a packed
representation of the object database directly, if you changed
"read_sha1_file()" to read these kinds of packs.

The latter is partiularly useful to generate a "packed history", ie you
could pack up your old history efficiently, but still have it available
(at a performance hit, of course).

I haven't actually written an unpacker yet, so the end result has not
been verified in any way yet.  I obviously always write bug-free code,
so it just has to work, no?

A "patch ID" is nothing but a SHA1 of the diff associated with a patch,
with whitespace and line numbers ignored.  As such, it's "reasonably
stable", but at the same time also reasonably unique, ie two patches
that have the same "patch ID" are almost guaranteed to be the same
thing.

IOW, you can use this thing to look for likely duplicate commits.

It's just a trivial wrapper, but it should make Jeff's kernel developer
guide to git look a bit less intimidating.

Btw, it's fun just looking at the merged git repository itself with
gitk, now that it has two "roots".

It is careful by default and refuses to overwrite old info, but if you
want to force everything to be re-read, use the "-f" flag.

Some day I'll make it take individual filenames too. Right now
it's all-or-nothing.

Fix permissions, and add trivial "reset" and "add" scripts.

The "reset" script just resets the index back to head, while the "add"
script is just a crutch for people used to do "cvs add".

It's a simple helper that depending on the arguments will either
use git-diff-files, git-diff-cache or git-diff-tree.

It's an incredibly cheesy helper that changes human-readable revision
arguments into the git-rev-list argument format.

You can use it to do something like this:

	git-rev-list --pretty $(git-rev-parse --default HEAD "$@")

which is what git-log-script will become. Here git-rev-parse will
then allow you to use arguments like "v2.6.12-rc5.." or similar
human-readable ranges.

It's really quite stupid: "a..b" will be converted into "a" and "^b" if
"a" and "b" are valid object pointers.  And the "--default" case will be
used if nothing but flags have been seen, so that you can default to a
certain argument if there are no other ranges.

The diff-* brothers acquired a sibling, git-diff-stages.  With
an unmerged index file, you specify two stage numbers and it
shows the differences between them.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This gets the "cvs2git" program from the old git-tools
archive, and adds a nice script around it that makes it
much easier to use.

With this, you should be able to import a CVS archive
using just a simple

	git cvsimport <cvsroot> <module>

and you're done. At least it worked for my one single test.

NOTE!! This may need tweaking. It currently expects (and
verifies) that cvsps version 2.1 is installed, but you
can't actually set any of the cvsps parameters, like the
time fuzz.

This patch adds code to read a hash out of a specified file under
{GIT_DIR}/refs/, and to write such files atomically and optionally with an
compare and lock.
Signed-off-by: NDaniel Barkalow <barkalow@iabervon.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Needed for the bignum stuff used by merge-order.

This patch linearises the GIT commit history graph into merge order
which is defined by invariants specified in Documentation/git-rev-list.txt.

The linearisation produced by this patch is superior in an objective sense
to that produced by the existing git-rev-list implementation in that
the linearisation produced is guaranteed to have the minimum number of
discontinuities, where a discontinuity is defined as an adjacent pair of
commits in the output list which are not related in a direct child-parent
relationship.

With this patch a graph like this:

	a4 ---
	| \   \
	|  b4 |
	|/ |  |
	a3 |  |
	|  |  |
	a2 |  |
	|  |  c3
	|  |  |
	|  |  c2
	|  b3 |
	|  | /|
	|  b2 |
	|  |  c1
	|  | /
	|  b1
	a1 |
	|  |
	a0 |
	| /
	root

Sorts like this:

	= a4
	| c3
	| c2
	| c1
	^ b4
	| b3
	| b2
	| b1
	^ a3
	| a2
	| a1
	| a0
	= root

Instead of this:

	= a4
	| c3
	^ b4
	| a3
	^ c2
	^ b3
	^ a2
	^ b2
	^ c1
	^ a1
	^ b1
	^ a0
	= root

A test script, t/t6000-rev-list.sh, includes a test which demonstrates
that the linearisation produced by --merge-order has less discontinuities
than the linearisation produced by git-rev-list without the --merge-order
flag specified. To see this, do the following:

	cd t
	./t6000-rev-list.sh
	cd trash
	cat actual-default-order
	cat actual-merge-order

The existing behaviour of git-rev-list is preserved, by default. To obtain
the modified behaviour, specify --merge-order or --merge-order --show-breaks
on the command line.

This version of the patch has been tested on the git repository and also on the linux-2.6
repository and has reasonable performance on both - ~50-100% slower than the original algorithm.

This version of the patch has incorporated a functional equivalent of the Linus' output limiting
algorithm into the merge-order algorithm itself. This operates per the notes associated
with Linus' commit 337cb3fb.

This version has incorporated Linus' feedback regarding proposed changes to rev-list.c.
(see: [PATCH] Factor out filtering in rev-list.c)

This version has improved the way sort_first_epoch marks commits as uninteresting.

For more details about this change, refer to Documentation/git-rev-list.txt
and http://blackcubes.dyndns.org/epoch/.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Bad Linus.

The merge stuff will want it soon, and we don't want to
duplicate all the work..

In preparation for 1.0 release, this makes the command names
consistent with others in git-*-pull family.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Somebody finally came through - Jeff Garzik gets a gold
star for writing a shortlog script for git, so that I
can do nice release announcments again.

I added name translations from the current kernel history
(and git, for that matter). Hopefully it won't grow at
nearly the same rate the BK equivalent did, since 99% of
the time git records the full name already.

Usage: just do

        git-rev-list --pretty HEAD ^LAST_HEAD | git-shortlog

or, in fact, use any of the other tools (git-diff-tree,
git-whatchanged etc) that use the default "pretty" commit format.

The "git" script is just shorthand: "git xyz <args>" will just execute
"git-xyz-script <args>", which is useful for people used to the CVS
naming convention. So "git log" will run the new git-log-script, which
is just a wrapper around the new pretty-printing git-rev-list.

Cheesy.

A new diffcore filter diffcore-order is introduced.  This takes
a text file each of whose line is a shell glob pattern.  Patches
that match a glob pattern on an earlier line in the file are
output before patches that match a later line, and patches that
do not match any glob pattern are output last.

A typical orderfile for git project probably should look like
this:

    README
    Makefile
    Documentation
    *.h
    *.c
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is meant to make raw git not hugely less usable than something
like raw CVS. I want to make a 1.0 release of the plumbing, and the
actual commit part was just too intimidating.

A new diffcore transformation, diffcore-break.c, is introduced.

When the -B flag is given, a patch that represents a complete
rewrite is broken into a deletion followed by a creation.  This
makes it easier to review such a complete rewrite patch.

The -B flag takes the same syntax as the -M and -C flags to
specify the minimum amount of non-source material the resulting
file needs to have to be considered a complete rewrite, and
defaults to 99% if not specified.

As the new test t4008-diff-break-rewrite.sh demonstrates, if a
file is a complete rewrite, it is broken into a delete/create
pair, which can further be subjected to the usual rename
detection if -M or -C is used.  For example, if file0 gets
completely rewritten to make it as if it were rather based on
file1 which itself disappeared, the following happens:

    The original change looks like this:

	file0     --> file0' (quite different from file0)
	file1     --> /dev/null

    After diffcore-break runs, it would become this:

	file0     --> /dev/null
	/dev/null --> file0'
	file1     --> /dev/null

    Then diffcore-rename matches them up:

	file1     --> file0'

The internal score values are finer grained now.  Earlier
maximum of 10000 has been raised to 60000; there is no user
visible changes but there is no reason to waste available bits.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The second round similarity estimator simply used the size of
the xdelta itself to estimate the extent of damage.  This patch
keeps that logic to detect big insertions to terminate the check
early, but otherwise looks at the generated delta in order to
estimate the extent of edit more accurately.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This applies git patches (and old-style unified diffs)
in the index, rather than doing it in the working directory.

That allows for a lot more flexibility, and means that if a
patch fails, we aren't going to mess up the working directory.

NOTE! This is just the first cut at it, and right now it only
parses the incoming patch, it doesn't actually apply it yet.

Thomas Glanzmann points out that it doesn't work well with different
clients accessing the repository over NFS - they have different views
on what the "device" for the filesystem is.

Of course, other filesystems may not even have stable inode numbers.
But we don't care. At least for now.

Signed-off-by: NThomas Glanzmann <sithglan@stud.uni-erlangen.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This allows you to just fetch stuff first, inspect it, and then
resolve the merge separately if everything looks good.

This moves the path selection logic from individual programs to a new
diffcore transformer (diff-tree still needs to have its own for
performance reasons).  Also the header printing code in diff-tree was
tweaked not to produce anything when pickaxe is in effect and there is
nothing interesting to report.  An interesting example is the following
in the GIT archive itself:

    $ git-whatchanged -p -C -S'or something in a real script'
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

(Or, if somebody disagrees, we should have a "make distclean").

This steals the "pickaxe" feature from JIT and make it available
to the bare Plumbing layer.  From the command line, the user
gives a string he is intersted in.

Using the diff-core infrastructure previously introduced, it
filters the differences to limit the output only to the diffs
between <src> and <dst> where the string appears only in one but
not in the other.  For example:

 $ ./git-rev-list HEAD | ./git-diff-tree -Sdiff-tree-helper --stdin -M

would show the diffs that touch the string "diff-tree-helper".

In real software-archaeologist application, you would typically
look for a few to several lines of code and see where that code
came from.

The "pickaxe" module runs after "rename/copy detection" module,
so it even crosses the file rename boundary, as the above
example demonstrates.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>