Commit Graph

13 Commits

Author SHA1 Message Date
Mike Ralphson
3ea3c215c0 Fix typos / spelling in comments
Signed-off-by: Mike Ralphson <mike@abacus.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-04-22 19:02:12 -07:00
Benjamin Kramer
8e24cbaeaf Fix various dead stores found by the clang static analyzer
http-push.c::finish_request():
  request is initialized by the for loop

index-pack.c::free_base_data():
  b is initialized by the for loop

merge-recursive.c::process_renames():
  move compare to narrower scope, and remove unused assignments to it
  remove unused variable renames2

xdiff/xdiffi.c::xdl_recs_cmp():
  remove unused variable ec

xdiff/xemit.c::xdl_emit_diff():
  xche is always overwritten

Signed-off-by: Benjamin Kramer <benny.kra@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-03-15 18:25:24 -07:00
Johannes Schindelin
92b7de93fb Implement the patience diff algorithm
The patience diff algorithm produces slightly more intuitive output
than the classic Myers algorithm, as it does not try to minimize the
number of +/- lines first, but tries to preserve the lines that are
unique.

To this end, it first determines lines that are unique in both files,
then the maximal sequence which preserves the order (relative to both
files) is extracted.

Starting from this initial set of common lines, the rest of the lines
is handled recursively, with Myers' algorithm as a fallback when
the patience algorithm fails (due to no common unique lines).

This patch includes memory leak fixes by Pierre Habouzit.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-07 13:35:44 -08:00
Brian Downing
ef2e62fe23 Allow alternate "low-level" emit function from xdl_diff
For some users (e.g. git blame), getting textual patch output is just
extra work, as they can get all the information they need from the low-
level diff structures.  Allow for an alternate low-level emit function
to be defined to allow bypassing the textual patch generation; set
xemitconf_t's emit_func member to enable this.

The (void (*)()) type is pretty ugly, but the alternative would be to
include most of the private xdiff headers in xdiff.h to get the types
required for the "proper" function prototype.  Also, a (void *) won't
work, as ANSI C doesn't allow a function pointer to be cast to an
object pointer.

Signed-off-by: Brian Downing <bdowning@lavos.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-10-25 12:09:31 -07:00
Guido Ostkamp
a777e9ca54 Remove unreachable statements
Solaris Workshop Compiler found a few unreachable statements.

Signed-off-by: Guido Ostkamp <git@ostkamp.fastmail.fm>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-15 21:23:47 -08:00
Junio C Hamano
a6080a0a44 War on whitespace
This uses "git-apply --whitespace=strip" to fix whitespace errors that have
crept in to our source files over time.  There are a few files that need
to have trailing whitespaces (most notably, test vectors).  The results
still passes the test, and build result in Documentation/ area is unchanged.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-07 00:04:01 -07:00
Johannes Schindelin
857b933e04 xdiff: add xdl_merge()
This new function implements the functionality of RCS merge, but
in-memory. It returns < 0 on error, otherwise the number of conflicts.

Finding the conflicting lines can be a very expensive task. You can
control the eagerness of this algorithm:

- a level value of 0 means that all overlapping changes are treated
  as conflicts,
- a value of 1 means that if the overlapping changes are identical,
  it is not treated as a conflict.
- If you set level to 2, overlapping changes will be analyzed, so that
  almost identical changes will not result in huge conflicts. Rather,
  only the conflicting lines will be shown inside conflict markers.

With each increasing level, the algorithm gets slower, but more accurate.
Note that the code for level 2 depends on the simple definition of
mmfile_t specific to git, and therefore it will be harder to port that
to LibXDiff.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-02 17:28:19 -08:00
Pavel Roskin
82e5a82fd7 Fix more typos, primarily in the code
The only visible change is that git-blame doesn't understand
"--compability" anymore, but it does accept "--compatibility" instead,
which is already documented.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-07-10 00:36:44 -07:00
Johannes Schindelin
0d21efa51c Teach diff about -b and -w flags
This adds -b (--ignore-space-change) and -w (--ignore-all-space) flags to
diff. The main part of the patch is teaching libxdiff about it.

[jc: renamed xdl_line_match() to xdl_recmatch() since the former is used
 for different purposes in xpatchi.c which is in the parts of the upstream
 source we do not use.]

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-23 17:35:27 -07:00
Davide Libenzi
295ba2fb89 xdiff: post-process hunks to make them consistent. 2006-04-13 16:48:45 -07:00
Marco Roeland
0ed49a3ed9 xdiff/xdiffi.c: fix warnings about possibly uninitialized variables
Compiling this module gave the following warnings (some double dutch!):

xdiff/xdiffi.c: In functie 'xdl_recs_cmp':
xdiff/xdiffi.c:298: let op: 'spl.i1' may be used uninitialized in this function
xdiff/xdiffi.c:298: let op: 'spl.i2' may be used uninitialized in this function
xdiff/xdiffi.c:219: let op: 'fbest1' may be used uninitialized in this function
xdiff/xdiffi.c:219: let op: 'bbest1' may be used uninitialized in this function

A superficial tracking of their usage, without deeper knowledge about the
algorithm, indeed confirms that there are code paths on which these
variables will be used uninitialized. In practice these code paths might never
be reached, but then these fixes will not change the algorithm. If these
code paths are ever reached we now at least have a predictable outcome. And
should the very small performance impact of these initializations be
noticeable, then they should at least be replaced by comments why certain
code paths will never be reached.

Some extra initializations in this patch now fix the warnings.
2006-04-08 23:35:22 -07:00
Davide Libenzi
ca557afff9 Clean-up trivially redundant diff.
Also corrects the line numbers in unified output when using
zero lines context.
2006-04-04 00:11:09 -07:00
Linus Torvalds
3443546f6e Use a *real* built-in diff generator
This uses a simplified libxdiff setup to generate unified diffs _without_
doing  fork/execve of GNU "diff".

This has several huge advantages, for example:

Before:

	[torvalds@g5 linux]$ time git diff v2.6.16.. > /dev/null

	real    0m24.818s
	user    0m13.332s
	sys     0m8.664s

After:

	[torvalds@g5 linux]$ time git diff v2.6.16.. > /dev/null

	real    0m4.563s
	user    0m2.944s
	sys     0m1.580s

and the fact that this should be a lot more portable (ie we can ignore all
the issues with doing fork/execve under Windows).

Perhaps even more importantly, this allows us to do diffs without actually
ever writing out the git file contents to a temporary file (and without
any of the shell quoting issues on filenames etc etc).

NOTE! THIS PATCH DOES NOT DO THAT OPTIMIZATION YET! I was lazy, and the
current "diff-core" code actually will always write the temp-files,
because it used to be something that you simply had to do. So this current
one actually writes a temp-file like before, and then reads it into memory
again just to do the diff. Stupid.

But if this basic infrastructure is accepted, we can start switching over
diff-core to not write temp-files, which should speed things up even
further, especially when doing big tree-to-tree diffs.

Now, in the interest of full disclosure, I should also point out a few
downsides:

 - the libxdiff algorithm is different, and I bet GNU diff has gotten a
   lot more testing. And the thing is, generating a diff is not an exact
   science - you can get two different diffs (and you will), and they can
   both be perfectly valid. So it's not possible to "validate" the
   libxdiff output by just comparing it against GNU diff.

 - GNU diff does some nice eye-candy, like trying to figure out what the
   last function was, and adding that information to the "@@ .." line.
   libxdiff doesn't do that.

 - The libxdiff thing has some known deficiencies. In particular, it gets
   the "\No newline at end of file" case wrong. So this is currently for
   the experimental branch only. I hope Davide will help fix it.

That said, I think the huge performance advantage, and the fact that it
integrates better is definitely worth it. But it should go into a
development branch at least due to the missing newline issue.

Technical note: this is based on libxdiff-0.17, but I did some surgery to
get rid of the extraneous fat - stuff that git doesn't need, and seriously
cutting down on mmfile_t, which had much more capabilities than the diff
algorithm either needed or used. In this version, "mmfile_t" is just a
trivial <pointer,length> tuple.

That said, I tried to keep the differences to simple removals, so that you
can do a diff between this and the libxdiff origin, and you'll basically
see just things getting deleted. Even the mmfile_t simplifications are
left in a state where the diffs should be readable.

Apologies to Davide, whom I'd love to get feedback on this all from (I
wrote my own "fill_mmfile()" for the new simpler mmfile_t format: the old
complex format had a helper function for that, but I did my surgery with
the goal in mind that eventually we _should_ just do

	mmfile_t mf;

	buf = read_sha1_file(sha1, type, &size);
	mf->ptr = buf;
	mf->size = size;
	.. use "mf" directly ..

which was really a nightmare with the old "helpful" mmfile_t, and really
is that easy with the new cut-down interfaces).

[ Btw, as any hawk-eye can see from the diff, this was actually generated
  with itself, so it is "self-hosting". That's about all the testing it
  has gotten, along with the above kernel diff, which eye-balls correctly,
  but shows the newline issue when you double-check it with "git-apply" ]

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-25 16:49:58 -08:00