When describing more than one, we need to clear the commit marks
before handling the next one, but most of the time we are
running it for only one commit, and in such a case this clearing
phase is totally unnecessary.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The main loop was prepared to take more than one revs, but the actual
naming logic wad not (it used pop_most_recent_commit while forgetting
that the commit marks stay after it's done).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

ISO C99 (and GCC 3.x or later) lets you write a flexible array
at the end of a structure, like this:

	struct frotz {
		int xyzzy;
		char nitfol[]; /* more */
	};

GCC 2.95 and 2.96 let you to do this with "char nitfol[0]";
unfortunately this is not allowed by ISO C90.

This declares such construct like this:

	struct frotz {
		int xyzzy;
		char nitfol[FLEX_ARRAY]; /* more */
	};

and git-compat-util.h defines FLEX_ARRAY to 0 for gcc 2.95 and
empty for others.

If you are using a C90 C compiler, you should be able
to override this with CFLAGS=-DFLEX_ARRAY=1 from the
command line of "make".
Signed-off-by: NJunio C Hamano <junkio@cox.net>

dietlibc versions of malloc, calloc and realloc all return NULL if
they're told to allocate 0 bytes, causes the x* wrappers to die().

There are several more places where these calls could end up asking
for 0 bytes, too...

Maybe simply not die()-ing in the x* wrappers if 0/NULL is returned
when the requested size is zero is a safer and easier way to go.
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

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

Store pointers to referenced objects in a variable sized array instead
of linked list.  This cuts down memory usage of utilities which use
object references; e.g., git-fsck-objects --full on the git.git
repository consumes about 2 MB of memory tracked by Massif instead of
7 MB before the change.  Object refs are still the biggest consumer of
memory (57%), but the malloc overhead for a single block instead of a
linked list is substantially smaller.
Signed-off-by: NSergey Vlasov <vsu@altlinux.ru>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This fixes git-rev-list so that when there are multiple branches, we still
sort the heads in proper approximate date order even when sorting the
output topologically.

This makes things like

	gitk --all -d

work sanely and show the branches in date order (where "date order" is
obviously modified by the paren-child dependency requirements of the
topological sort).

The trivial fix is to just build the "work" list in date order rather than
inserting the new work entries at the beginning.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

git log without --pretty showed author and author-date, while
with --pretty=full showed author and committer but no dates.
The new formatting option, --pretty=fuller, shows both name and
timestamp for author and committer.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

One caller of deref_tag() was not careful enough to make sure
what deref_tag() returned was not NULL (i.e. we found a tag
object that points at an object we do not have).  Fix it, and
warn about refs that point at such an incomplete tag where
needed.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Do our own ctype.h, just to get the sane semantics: we want
locale-independence, _and_ we want the right signed behaviour. Plus we
only use a very small subset of ctype.h anyway (isspace, isalpha,
isdigit and isalnum).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

As pointed out on the list, git-rev-list can use a lot of memory.

One low-hanging fruit is to free the commit buffer for commits that we
parse. By default, parse_commit() will save away the buffer, since a lot
of cases do want it, and re-reading it continually would be unnecessary.
However, in many cases the buffer isn't actually necessary and saving it
just wastes memory.

We could just free the buffer ourselves, but especially in git-rev-list,
we actually end up using the helper functions that automatically add
parent commits to the commit lists, so we don't actually control the
commit parsing directly.

Instead, just make this behaviour of "parse_commit()" a global flag.
Maybe this is a bit tasteless, but it's very simple, and it makes a
noticable difference in memory usage.

Before the change:

	[torvalds@g5 linux]$ /usr/bin/time git-rev-list v2.6.12..HEAD > /dev/null
	0.26user 0.02system 0:00.28elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
	0inputs+0outputs (0major+3714minor)pagefaults 0swaps

after the change:

	[torvalds@g5 linux]$ /usr/bin/time git-rev-list v2.6.12..HEAD > /dev/null
	0.26user 0.00system 0:00.27elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
	0inputs+0outputs (0major+2433minor)pagefaults 0swaps

note how the minor faults have decreased from 3714 pages to 2433 pages.
That's all due to the fewer anonymous pages allocated to hold the comment
buffers and their metadata.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

... found by compiling them with gcc 2.95.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This reverts 6c5f9baa commit, whose
change breaks gcc-2.95.

Not that I ignore portability to compilers that are properly C99, but
keeping compilation with GCC working is more important, at least for
now.  We would probably end up declaring with "name[1]" and teach the
allocator to subtract one if we really aimed for portability, but that
is left for later rounds.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

C99 denotes variable-sized members with [], not [0].
Signed-off-by: NJason Riedy <ejr@cs.berkeley.edu>

The 'git show-branches' command turns out to be reasonably useful,
but painfully slow.  So rewrite it in C, using ideas from merge-base
while enhancing it a bit more.

 - Unlike show-branches, it can take --heads (show me all my
   heads), --tags (show me all my tags), or --all (both).

 - It can take --more=<number> to show beyond the merge-base.

 - It shows the short name for each commit in the extended SHA1
   syntax.

 - It can find merge-base for more than two heads.

Examples:

    $ git show-branch --more=6 HEAD

    is almost the same as "git log --pretty=oneline --max-count=6".

    $ git show-branch --merge-base master mhf misc

    finds the merge base of the three given heads.

    $ git show-branch master mhf misc

    shows logs from the top of these three branch heads, up to their
    common ancestor commit is shown.

    $ git show-branch --all --more=10

    is poor-man's gitk, showing all the tags and heads, and
    going back 10 commits beyond the merge base of those refs.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This introduces --pretty=oneline to git-rev-tree and
git-rev-list commands to show only the first line of the commit
message, without frills. 
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Again I left the v2.6.11-tree tag behind.  My bad.

This commit makes sure that we do not barf when pushing a ref
that is a non-commitish tag.  You can update a remote ref under
the following conditions:

 * You can always use --force.
 * Creating a brand new ref is OK.
 * If the remote ref is exactly the same as what you are
   pushing, it is OK (nothing is pushed).
 * You can replace a commitish with another commitish which is a
   descendant of it, if you can verify the ancestry between them;
   this and the above means you have to have what you are replacing.
 * Otherwise you cannot update; you need to use --force.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Introduce a new file $GIT_DIR/info/grafts (or $GIT_GRAFT_FILE)
which is a list of "fake commit parent records".  Each line of
this file is a commit ID, followed by parent commit IDs, all
40-byte hex SHA1 separated by a single SP in between.  The
records override the parent information we would normally read
from the commit objects, allowing both adding "fake" parents
(i.e. grafting), and pretending as if a commit is not a child of
some of its real parents (i.e. cauterizing).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This was brought on by a bad tree of Thomas Gleixner, where some bogus
commit objects weren't warned about properly
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When we allow a tag object in place of a commit object, we only
dereferenced the given tag once, which causes a tag that points at a tag
that points at a commit to be rejected.  Instead, dereference tag
repeatedly until we get a non-tag.

This patch makes change to two functions:

 - commit.c::lookup_commit_reference() is used by merge-base,
   rev-tree and rev-parse to convert user supplied SHA1 to that of
   a commit.
 - rev-list uses its own get_commit_reference() to do the same.

Dereferencing tags this way helps both of these uses.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This introduces an in-place topological sort procedure to commit.c.

Given a list of commits, sort_in_topological_order() will perform an in-place
topological sort of that list.

The invariant that applies to the resulting list is:

       a reachable from b => ord(b) < ord(a)

This invariant is weaker than the --merge-order invariant, but is cheaper
to calculate (assuming the list has been identified) and will serve any
purpose where only a minimal topological order guarantee is required.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Same argument order, same return type.  This allows us to use a function
pointer to choose one over the other.

Also move the common implementation of parsing the --pretty argument
format into commit.c rather than having duplicates in diff-tree.c and
rev-list.c.

We used to keep the parents in reverse order in the commit_list.  Most
users don't care, but it's wrong, and the next commit does care.

Otherwise the "git log" information doesn't tell enough to make sense of
a merge.

I'll need to add some parent information for regular entries too, I
think, but the merge is more important.

Make 'sha1' parameters const where possible
Signed-off-by: NJason McMullan <jason.mcmullan@timesys.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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>

You can ask to print out "raw" format (full headers, full body),
"medium" format (author and date, full body) or "short" format
(author only, condensed body).

Use "git-rev-list --pretty=short HEAD | less -S" for an example.

It's really just the header printign function from diff-tree.c,
and it's usable for other things too.

This is useful for when we want to insert the next one after
this new one, for example.

object.

A fair number of the users potentially want to look at the
commit objects more closely, and if you worry about memory
leaking in certain applications, you can always do a

	free(commit->buffer);
	commit->buffer = NULL;

by hand after parsing them.

Add <limits.h> to the include files handled by "cache.h", and remove
extraneous #include directives from various .c files. The rule is that
"cache.h" gets all the basic stuff, so that we'll have as few system
dependencies as possible.

This adds knowledge of delta objects to fsck-cache and various object
parsing code.  A new switch to git-fsck-cache is provided to display the
maximum delta depth found in a repository.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It's pretty much the same as "lookup_commit()", but it will take
tags too, and look up the commit (if any) associated with them.

It turns out that parse_object() is loading and decompressing given
object to free it just before calling the specific object parsing
function which does mmap and decompress the same object again. This
patch introduces the ability to parse specific objects directly from a
memory buffer.

Without this patch, running git-fsck-cache on the kernel repositorytake:

	real    0m13.006s
	user    0m11.421s
	sys     0m1.218s

With this patch applied:

	real    0m8.060s
	user    0m7.071s
	sys     0m0.710s

The performance increase is significant, and this is kind of a
prerequisite for sane delta object support with fsck.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes memory leaks in parse_object() and related functions;
these leaks were very noticeable when running git-fsck-cache.
Signed-off-by: NSergey Vlasov <vsu@altlinux.ru>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Introduce xmalloc and xrealloc to die gracefully with a descriptive
message when out of memory, rather than taking a SIGSEGV. 

Signed-off-by: Christopher Li<chrislgit@chrisli.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

That would SIGSEGV.

The type doesn't come from the parsing, the type also has to match the usage.

Otherwise we can have objects without a type, which is not good.