Here is a SHA1 implementation with the core written in PPC assembly.
On my 2GHz G5, it does 218MB/s, compared to 135MB/s for the openssl
version or 45MB/s for the mozilla version.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This one is about a million times simpler, and much more likely to be
correct too.

Instead of trying to match up a tree object against the index, we just
read in the tree object side-by-side into the index, and just walk the
resulting index file. This was what all the read-tree cleanups were
all getting to.

Next step: make "diff-cache" use it.

This is preparation for moving parts of it into "tree.c" to be used
as a library function.

This one includes the Mozilla SHA1 implementation sent in by Edgar Toernig.
It's dual-licenced under MPL-1.1 or GPL, so in the context of git, we
obviously use the GPL version. 

Side note: the Mozilla SHA1 implementation is about twice as fast as the
default openssl one on my G5, but the default openssl one has optimized
x86 assembly language on x86. So choose wisely.

zlib and libssl.

I'll start giving people choices here..

The old revision.h helper header isn't used any more, but I never noticed
it until I started grepping for ULONG_MAX users.

We use that to specify alternative index files, which can be useful
if you want to (for example) generate a temporary index file to do
some specific operation that you don't want to mess with your main
one with.

It defaults to the regular ".git/index" if it hasn't been specified.

This basically makes it trivial to use checkout-cache as a "export as
tree" function. Just read the desired tree into the index, and do a

	checkout-cache --prefix=export-dir/ -a

and checkout-cache will "export" the cache into the specified directory.

NOTE! The final "/" is important. The exported name is literally just
prefixed with the specified string, so you can also do something like

	checkout-cache --prefix=.merged- Makefile

to check out the currently cached copy of "Makefile" into the file
".merged-Makefile".

The rev-tree thing just happened to work. It shouldn't have.

Usage string fixes to make maintenance easier (only one instance
of a string to update not multiple copies).  I've spotted and
corrected inconsistent usage text in diff-tree while doing this.

Also diff-cache and read-tree usage text have been corrected to
match their up-to-date features.  Earlier, neither "--cached"
form of diff-cache nor "-m single-merge" form of read-tree were
described. 
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The high-level helpers seem to have forgotten what to do with sha1
names.

Updates read-tree to use read_tree_with_tree_or_commit_sha1()
function.  The command can take either tree or commit IDs with
this patch.

The change involves a slight modification of how it recurses down
the tree.  Earlier the caller only supplied SHA1 and the recurser
read the object using it, but now it is the caller's responsibility
to read the object and give it to the recurser.  This matches the
way recursive behaviour is done in other tree- related commands.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Updates ls-tree.c to use read_tree_with_tree_or_commit_sha1()
function.  The command can take either tree or commit IDs with
this patch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Updates diff-tree.c to use read_tree_with_tree_or_commit_sha1()
function.  The command can take either tree or commit IDs with this patch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Updates diff-cache.c to use read_tree_with_tree_or_commit_sha1()
function.  The end-user visible result is the same --- the command
takes either tree or commit ID.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch implements read_tree_with_tree_or_commit_sha1(),
which can be used when you are interested in reading an unpacked
raw tree data but you do not know nor care if the SHA1 you
obtained your user is a tree ID or a commit ID.  Before this
function's introduction, you would have called read_sha1_file(),
examined its type, parsed it to call read_sha1_file() again if
it is a commit, and verified that the resulting object is a
tree.  Instead, this function does that for you.  It returns
NULL if the given SHA1 is not either a tree or a commit.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use a generic rule for executables that depend only on the corresponding
.o and on $(LIB_FILE).
Signed-Off-By: NAndre Noll <maan@systemlinux.org>
Signed-Off-By: NLinus Torvalds <torvalds@osdl.org>

(Nobody should use -O3. It just makes bad inlining decisions).

This allows us to both calculate it and verify it faster.

No point in making 17,000 small writes when you can make just
a couple of hundred nice 8kB writes instead and save a lot
of time.

Avoid the compression.

Happily, convert-cache just magically fixes all errors.

And add a "convert-cache" program to convert from old-style
to new-style.

Factor mkdir calls into common safe_create_dir subroutine.
Signed-Off-By: NZach Welch <zw@superlucidity.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Normalize init-db environment variable handling, allowing the creation
of object directories with something other than DEFAULT_DB_ENVIRONMENT.
Signed-Off-By: NZach Welch <zw@superlucidity.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Consolidate comments at top of main.
Signed-Off-By: NZach Welch <zw@superlucidity.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Sometimes it's just easier to not have to look up the "commit"->"tree"
translation by hand first. It's trivial to do inside diff-tree, and
it's just being polite.

the current cache state and/or working directory.

Very useful to see what has changed since the last commit, either in
the index file or in the whole working directory.

Also very possibly very buggy. Matching the two up is not entirely
trivial.

It's still just a guess, and the result is not a real email
address anyway. If you want to, you can use COMMIT_AUTHOR_EMAIL
to correct for any git guesses.

Noted by Tony Luck.

as a set of patches and commentary.

You'd want something like this if you are tracking a git archive
in another SCM format. Notably, we want something like that for
BK users.

Noted by Aaron Straus

reading a single tree too. That should speed up a
trivial merge noticeably.

Also, don't bother reading back the tree we just wrote
when we committed a real merge. It had better be the
same one we still have..

This one just reads one tree, but picks up any matching stat information
from the old index.

old index state if the result matches.

This leaves the stat information in the result tree for any trivial
merges, which is just the way we like it.

Also exit gracefully if the HEAD pull failed, rather than use
a possibly stale MERGE_HEAD.

Yes, the "parse_commit()" already checks for this condition, but
we need to check for it in rev-tree too, so that we don't start
walking the parent chain unnecessarily.