This prepares but does not yet implement a look-ahead in the index entries
when traverse-trees.c decides to give us tree entries in an order that
does not match what is in the index.

A case where a look-ahead in the index is necessary happens when merging
branch B into branch A while the index matches the current branch A, using
a tree O as their common ancestor, and these three trees looks like this:

   O        A       B
   t                t
   t-i      t-i     t-i
   t-j      t-j
            t/1
            t/2

The traverse_trees() function gets "t", "t-i" and "t" from trees O, A and
B first, and notices that A may have a matching "t" behind "t-i" and "t-j"
(indeed it does), and tells A to give that entry instead.  After unpacking
blob "t" from tree B (as it hasn't changed since O in B and A removed it,
it will result in its removal), it descends into directory "t/".

The side that walked index in parallel to the tree traversal used to be
implemented with one pointer, o->pos, that points at the next index entry
to be processed.  When this happens, the pointer o->pos still points at
"t-i" that is the first entry.  We should be able to skip "t-i" and "t-j"
and locate "t/1" from the index while the recursive invocation of
traverse_trees() walks and match entries found there, and later come back
to process "t-i".

While that look-ahead is not implemented yet, this adds a flag bit,
CE_UNPACKED, to mark the entries in the index that has already been
processed.  o->pos pointer has been renamed to o->cache_bottom and it
points at the first entry that may still need to be processed.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

20a16eb3 (unpack_trees(): fix diff-index regression., 2008-03-10) adjusted
diff-index to the new world order since 34110cd4 (Make 'unpack_trees()'
have a separate source and destination index, 2008-03-06).  Callbacks are
expected to return anything non-negative as "success", and instead of
reporting how many index entries they have processed, they are expected to
advance o->pos themselves.  The code did so, but a stale comment was left
behind.
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>

When comparing the index and a tree, we used to read the contents of the
tree into stage #1 of the index and compared them with stage #0.  In order
not to lose sight of entries originally unmerged in the index, we hoisted
them to stage #3 before reading the tree.

Commit d1f2d7e8 (Make run_diff_index() use unpack_trees(), not read_tree(),
2008-01-19) changed all this.  These days, we instead use unpack_trees()
API to traverse the tree and compare the contents with the index, without
modifying the index at all.  There is no reason to hoist the unmerged
entries to stage #3 anymore.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Since an earlier change to diff-index by d1f2d7e8 (Make run_diff_index()
use unpack_trees(), not read_tree(), 2008-01-19), we stopped reporting an
unmerged path that does not exist in the tree, but we should.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When find-copies-harder is in effect, the diff frontends are expected to
feed all paths, not just changed paths, to the diffcore, so that copy
sources can be picked up.  In such a case, not descending into subtrees
using the cache-tree information is simply wrong.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When running "diff-index --cached" after making a change to only a small
portion of the index, there is no point unpacking unchanged subtrees into
the index recursively, only to find that all entries match anyway.  Tweak
unpack_trees() logic that is used to read in the tree object to catch the
case where the tree entry we are looking at matches the index as a whole
by looking at the cache-tree.

As an exercise, after modifying a few paths in the kernel tree, here are
a few numbers on my Athlon 64X2 3800+:

    (without patch, hot cache)
    $ /usr/bin/time git diff --cached --raw
    :100644 100644 b57e1f5... e69de29... M  Makefile
    :100644 000000 8c86b72... 0000000... D  arch/x86/Makefile
    :000000 100644 0000000... e69de29... A  arche
    0.07user 0.02system 0:00.09elapsed 102%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+0outputs (0major+9407minor)pagefaults 0swaps

    (with patch, hot cache)
    $ /usr/bin/time ../git.git/git-diff --cached --raw
    :100644 100644 b57e1f5... e69de29... M  Makefile
    :100644 000000 8c86b72... 0000000... D  arch/x86/Makefile
    :000000 100644 0000000... e69de29... A  arche
    0.02user 0.00system 0:00.02elapsed 103%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+0outputs (0major+2446minor)pagefaults 0swaps

Cold cache numbers are very impressive, but it does not matter very much
in practice:

    (without patch, cold cache)
    $ su root sh -c 'echo 3 >/proc/sys/vm/drop_caches'
    $ /usr/bin/time git diff --cached --raw
    :100644 100644 b57e1f5... e69de29... M  Makefile
    :100644 000000 8c86b72... 0000000... D  arch/x86/Makefile
    :000000 100644 0000000... e69de29... A  arche
    0.06user 0.17system 0:10.26elapsed 2%CPU (0avgtext+0avgdata 0maxresident)k
    247032inputs+0outputs (1172major+8237minor)pagefaults 0swaps

    (with patch, cold cache)
    $ su root sh -c 'echo 3 >/proc/sys/vm/drop_caches'
    $ /usr/bin/time ../git.git/git-diff --cached --raw
    :100644 100644 b57e1f5... e69de29... M  Makefile
    :100644 000000 8c86b72... 0000000... D  arch/x86/Makefile
    :000000 100644 0000000... e69de29... A  arche
    0.02user 0.01system 0:01.01elapsed 3%CPU (0avgtext+0avgdata 0maxresident)k
    18440inputs+0outputs (79major+2369minor)pagefaults 0swaps

This of course helps "git status" as well.

    (without patch, hot cache)
    $ /usr/bin/time ../git.git/git-status >/dev/null
    0.17user 0.18system 0:00.35elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+5336outputs (0major+10970minor)pagefaults 0swaps

    (with patch, hot cache)
    $ /usr/bin/time ../git.git/git-status >/dev/null
    0.10user 0.16system 0:00.27elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+5336outputs (0major+3921minor)pagefaults 0swaps
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we ask get_stat_data() to get the mode and size of an index entry,
we can avoid the lstat() call if we have marked the index entry as being
uptodate due to earlier lstat() calls.

This avoids a lot of unnecessary lstat() calls in eg 'git checkout',
where the last phase shows the differences to the working tree
(requiring a diff), but earlier phases have already verified the index.

On the kernel repo (with a fast machine and everything cached), this
changes timings of a nul 'git checkout' from

 - Before (best of ten):

	0.14user 0.05system 0:00.19elapsed 100%CPU (0avgtext+0avgdata 0maxresident)k
	0inputs+0outputs (0major+13237minor)pagefaults 0swaps

 - After
	0.11user 0.03system 0:00.15elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
	0inputs+0outputs (0major+13235minor)pagefaults 0swaps

so it can obviously be noticeable, although equally obviously it's not a
show-stopper on this particular machine. The difference is likely larger
on slower machines, or with operating systems that don't do as good a job
of name caching.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

index_is_dirty() in builtin-revert.c checks if the index is dirty.
This patch generalizes this function to check if the index differs
from a revision, i.e. the former index_is_dirty() behavior can now be
achieved by index_differs_from("HEAD", 0).

The second argument "diff_flags" allows to set further diff option
flags like DIFF_OPT_IGNORE_SUBMODULES. See DIFF_OPT_* macros in diff.h
for a list.

index_differs_from() seems to be useful for more than builtin-revert.c,
so it is moved into diff-lib.c and also used in builtin-commit.c.

Yet to mention:

 - "rev.abbrev = 0;" can be safely removed.
   This has no impact on performance or functioning of neither
   setup_revisions() nor run_diff_index().

 - rev.pending.objects is free()d because this fixes a leak.
   (Also see 295dd2ad "Fix memory leak in traverse_commit_list")
Mentored-by: NDaniel Barkalow <barkalow@iabervon.org>
Mentored-by: NChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: NStephan Beyer <s-beyer@gmx.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Swap function argument pair (length, string) into (string, length) to
conform with the commonly used order inside the GIT source code.

Also, add a note about this fact into the coding guidelines.
Signed-off-by: NKjetil Barvik <barvik@broadpark.no>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commit c40641b7, 'Optimize
symlink/directory detection' by Linus Torvalds, removed the 'char
*symcache' parameter to the has_symlink_leading_path() function.  This
made all variables currently named 'symcache' inside diff-lib.c
unnecessary.

This also let us throw away the 'struct oneway_unpack_data', and
instead directly use the 'struct rev_info *revs' member, which
was the only member left after removal of the 'symcache[] array'
member.  The 'struct oneway_unpack_data' was introduced by the
following commit:

  948dd346  "diff-files: careful when inspecting work tree items"

Impact: cleanup
        PATH_MAX bytes less memory stack usage in some cases
Signed-off-by: NKjetil Barvik <barvik@broadpark.no>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

With a new configuration "diff.mnemonicprefix", "git diff" shows the
differences between various combinations of preimage and postimage trees
with prefixes different from the standard "a/" and "b/".  Hopefully this
will make the distinction stand out for some people.

    "git diff" compares the (i)ndex and the (w)ork tree;
    "git diff HEAD" compares a (c)ommit and the (w)ork tree;
    "git diff --cached" compares a (c)ommit and the (i)ndex;
    "git-diff HEAD:file1 file2" compares an (o)bject and a (w)ork tree entity;
    "git diff --no-index a b" compares two non-git things (1) and (2).

Because these mnemonics now have meanings, they are swapped when reverse
diff is in effect and this feature is enabled.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If PATH_MAX on your system is smaller than a path stored, it may cause
buffer overflow and stack corruption in diff_addremove() and diff_change()
functions when running git-diff
Signed-off-by: NDmitry Potapov <dpotapov@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Even if "foo" and/or "bar" does not exist in index, "git diff foo bar"
should not change behaviour drastically from "git diff foo bar baz" or
"git diff foo".  A feature that "sometimes works and is handy" is an
unreliable cute hack.

"git diff foo bar" outside a git repository continues to work as a more
colourful alternative to "diff -u" as before.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is the base for making symlink detection in the middle fo a pathname
saner and (much) more efficient.

Under various loads, we want to verify that the full path leading up to a
filename is a real directory tree, and that when we successfully do an
'lstat()' on a filename, we don't get a false positive due to a symlink in
the middle of the path that git should have seen as a symlink, not as a
normal path component.

The 'has_symlink_leading_path()' function already did this, and cached
a single level of symlink information, but didn't cache the _lack_ of a
symlink, so the normal behaviour was actually the wrong way around, and we
ended up doing an 'lstat()' on each path component to check that it was a
real directory.

This caches the last detected full directory and symlink entries, and
speeds up especially deep directory structures a lot by avoiding to
lstat() all the directories leading up to each entry in the index.

[ This can - and should - probably be extended upon so that we eventually
  never do a bare 'lstat()' on any path entries at *all* when checking the
  index, but always check the full path carefully. Right now we do not
  generally check the whole path for all our normal quick index
  revalidation.

  We should also make sure that we're careful about all the invalidation,
  ie when we remove a link and replace it by a directory we should
  invalidate the symlink cache if it matches (and vice versa for the
  directory cache).

  But regardless, the basic function needs to be sane to do that. The old
  'has_symlink_leading_path()' was not capable enough - or indeed the code
  readable enough - to really do that sanely. So I'm pushing this as not
  just an optimization, but as a base for further work. ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The function is about checking for removed work tree item, so name it
accordingly to avoid future confusion.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

948dd346 (diff-index: careful when inspecting work tree items, 2008-03-30)
made the work tree check careful not to be fooled by a new directory that
exists at a place the index expects a blob.  For such a change to be a
typechange from blob to submodule, the new directory has to be a
repository.

However, if the index expects a submodule there, we should not insist the
work tree entity to be a repository --- a simple directory that is not a
full fledged repository (even an empty directory would do) should be
considered an unmodified subproject, because that is how a superproject
with a submodule is checked out sparsely by default.

This makes the function check_work_tree_entity() even more careful not to
report a submodule that is not checked out as removed.  It fixes the
recently added test in t4027.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The command

  git svn clone (URL of an empty SVN repo here)

works, creates an empty git repository. I can perform the initial
commit there, but then, "git svn dcommit" says :

Use of uninitialized value in concatenation (.) or string at .../git-svn line 414.
Committing to  ...
Unable to determine upstream SVN information from HEAD history

I guess a correct management of the initial commit in git-svn would be
hard to implement, but at least, the error message can be improved.
First step is something like the patch below, and better would be for
"git svn clone" to warn that it won't be able to do much with the
cloned repo.
Acked-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This does not make any difference when running diff-files alone, but if
you internally run run_diff_files() and then run other operations further
on the index, we do not have to run lstat(2) again on entries we already
have checked.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This fixes the same breakage in diff-files.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Earlier, if you changed a staged path into a directory in the work tree,
we happily ran lstat(2) on it and found that it exists, and declared that
the user changed it to a gitlink.

This is wrong for two reasons:

 (1) It may be a directory, but it may not be a submodule, and in the
     latter case, the change we need to report is "the blob at the path
     has disappeared".  We need to check with resolve_gitlink_ref() to be
     consistent with what "git add" and "git update-index --add" does.

 (2) lstat(2) may have succeeded only because a leading component of the
     path was turned into a symbolic link that points at something that
     exists in the work tree.  In such a case, the path itself does not
     exist anymore, as far as the index is concerned.

This fixes these breakages in diff-index that the previous patch has
exposed.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When skip_unmerged option is not given, unpack_trees() should not just
skip unmerged cache entries but keep them in the result for the caller to
sort them out.

For callers other than diff-index, the incoming index should never be
unmerged, but diff-index is a special case caller.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We will always unpack into our own internal index, but we will take the
source from wherever specified, and we will optionally write the result
to a specified index (optionally, because not everybody even _wants_ any
result: the index diffing really wants to just walk the tree and index
in parallel).

This ends up removing a fair number more lines than it adds, for the
simple reason that we can now skip all the crud that tried to be
oh-so-careful about maintaining our position in the index as we were
traversing and modifying it.  Since we don't actually modify the source
index any more, we can just update the 'o->pos' pointer without worrying
about whether an index entry got removed or replaced or added to.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is just a very mechanical conversion, and makes everybody set it to
'&the_index' before calling, but at least it makes it more explicit
where we work with the index.

The next stage would be to split that index usage up into a 'source' and
a 'destination' index, so that we can unpack into a different index than
we started out from.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The internal implementation of diff-index codepath used to use non const
pointer to pass sha1 around, but it did not have to.  With this, we can
also lose the private no_sha1[] array, as we can use the public null_sha1[]
array that exists exactly for the same purpose.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Return an error from unpack_trees() instead of calling die(), and exit
with an error in read-tree, builtin-commit, and diff-lib. merge-recursive
already expected an error return from unpack_trees, so it doesn't need to
be changed. The merge function can return negative to abort.

This will be used in builtin-checkout -m.
Signed-off-by: NDaniel Barkalow <barkalow@iabervon.org>

As in run_diff_index(), we call unpack_trees() with the oneway_diff()
function in do_diff_cache() now.  This makes the function diff_cache()
obsolete.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A plain "git commit" would still run lstat() a lot more than necessary,
because wt_status_print() would cause the index to be repeatedly flushed
and re-read by wt_read_cache(), and that would cause the CE_UPTODATE bit
to be lost, resulting in the files in the index being lstat'ed three
times each.

The reason why wt-status.c ended up invalidating and re-reading the
cache multiple times was that it uses "run_diff_index()", which in turn
uses "read_tree()" to populate the index with *both* the old index and
the tree we want to compare against.

So this patch re-writes run_diff_index() to not use read_tree(), but
instead use "unpack_trees()" to diff the index to a tree.  That, in
turn, means that we don't need to modify the index itself, which then
means that we don't need to invalidate it and re-read it!

This, together with the lstat() optimizations, means that "git commit"
on the kernel tree really only needs to lstat() the index entries once.
That noticeably cuts down on the cached timings.

Best time before:

	[torvalds@woody linux]$ time git commit > /dev/null
	real    0m0.399s
	user    0m0.232s
	sys     0m0.164s

Best time after:

	[torvalds@woody linux]$ time git commit > /dev/null
	real    0m0.254s
	user    0m0.140s
	sys     0m0.112s

so it's a noticeable improvement in addition to being a nice conceptual
cleanup (it's really not that pretty that "run_diff_index()" dirties the
index!)

Doing an "strace -c" on it also shows that as it cuts the number of
lstat() calls by two thirds, it goes from being lstat()-limited to being
limited by getdents() (which is the readdir system call):

Before:
	% time     seconds  usecs/call     calls    errors syscall
	------ ----------- ----------- --------- --------- ----------------
	 60.69    0.000704           0     69230        31 lstat
	 23.62    0.000274           0      5522           getdents
	  8.36    0.000097           0      5508      2638 open
	  2.59    0.000030           0      2869           close
	  2.50    0.000029           0       274           write
	  1.47    0.000017           0      2844           fstat

After:
	% time     seconds  usecs/call     calls    errors syscall
	------ ----------- ----------- --------- --------- ----------------
	 45.17    0.000276           0      5522           getdents
	 26.51    0.000162           0     23112        31 lstat
	 19.80    0.000121           0      5503      2638 open
	  4.91    0.000030           0      2864           close
	  1.48    0.000020           0       274           write
	  1.34    0.000018           0      2844           fstat
	...

It passes the test-suite for me, but this is another of one of those
really core functions, and certainly pretty subtle, so..

NOTE! The Linux lstat() system call is really quite cheap when everything
is cached, so the fact that this is quite noticeable on Linux is likely to
mean that it is *much* more noticeable on other operating systems. I bet
you'll see a much bigger performance improvement from this on Windows in
particular.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This converts the index explicitly on read and write to its on-disk
format, allowing the in-core format to contain more flags, and be
simpler.

In particular, the in-core format is now host-endian (as opposed to the
on-disk one that is network endian in order to be able to be shared
across machines) and as a result we can dispense with all the
htonl/ntohl on accesses to the cache_entry fields.

This will make it easier to make use of various temporary flags that do
not exist in the on-disk format.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Using the helper function to test for absolute paths makes porting easier.
Signed-off-by: NSteffen Prohaska <prohaska@zib.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

reverse_diff was a bit-value in disguise, it's merged in the flags now.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Earlier in commit 0781b8a9
(add_file_to_index: skip rehashing if the cached stat already
matches), add_file_to_index() were taught not to re-add the path
if it already matches the index.

The change meant well, but was not executed quite right.  It
used ie_modified() to see if the file on the work tree is really
different from the index, and skipped adding the contents if the
function says "not modified".

This was wrong.  There are three possible comparison results
between the index and the file in the work tree:

 - with lstat(2) we _know_ they are different.  E.g. if the
   length or the owner in the cached stat information is
   different from the length we just obtained from lstat(2), we
   can tell the file is modified without looking at the actual
   contents.

 - with lstat(2) we _know_ they are the same.  The same length,
   the same owner, the same everything (but this has a twist, as
   described below).

 - we cannot tell from lstat(2) information alone and need to go
   to the filesystem to actually compare.

The last case arises from what we call 'racy git' situation,
that can be caused with this sequence:

    $ echo hello >file
    $ git add file
    $ echo aeiou >file ;# the same length

If the second "echo" is done within the same filesystem
timestamp granularity as the first "echo", then the timestamp
recorded by "git add" and the timestamp we get from lstat(2)
will be the same, and we can mistakenly say the file is not
modified.  The path is called 'racily clean'.  We need to
reliably detect racily clean paths are in fact modified.

To solve this problem, when we write out the index, we mark the
index entry that has the same timestamp as the index file itself
(that is the time from the point of view of the filesystem) to
tell any later code that does the lstat(2) comparison not to
trust the cached stat info, and ie_modified() then actually goes
to the filesystem to compare the contents for such a path.

That's all good, but it should not be used for this "git add"
optimization, as the goal of "git add" is to actually update the
path in the index and make it stat-clean.  With the false
optimization, we did _not_ cause any data loss (after all, what
we failed to do was only to update the cached stat information),
but it made the following sequence leave the file stat dirty:

    $ echo hello >file
    $ git add file
    $ echo hello >file ;# the same contents
    $ git add file

The solution is not to use ie_modified() which goes to the
filesystem to see if it is really clean, but instead use
ie_match_stat() with "assume racily clean paths are dirty"
option, to force re-adding of such a path.

There was another problem with "git add -u".  The codepath
shares the same issue when adding the paths that are found to be
modified, but in addition, it asked "git diff-files" machinery
run_diff_files() function (which is "git diff-files") to list
the paths that are modified.  But "git diff-files" machinery
uses the same ie_modified() call so that it does not report
racily clean _and_ actually clean paths as modified, which is
not what we want.

The patch allows the callers of run_diff_files() to pass the
same "assume racily clean paths are dirty" option, and makes
"git-add -u" codepath to use that option, to discover and re-add
racily clean _and_ actually clean paths.

We could further optimize on top of this patch to differentiate
the case where the path really needs re-adding (i.e. the content
of the racily clean entry was indeed different) and the case
where only the cached stat information needs to be refreshed
(i.e. the racily clean entry was actually clean), but I do not
think it is worth it.

This patch applies to maint and all the way up.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

ce_match_stat() can be told:

 (1) to ignore CE_VALID bit (used under "assume unchanged" mode)
     and perform the stat comparison anyway;

 (2) not to perform the contents comparison for racily clean
     entries and report mismatch of cached stat information;

using its "option" parameter.  Give them symbolic constants.

Similarly, run_diff_files() can be told not to report anything
on removed paths.  Also give it a symbolic constant for that.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Code inspection by Linus found this.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we compare two non-tracked files, or explicitly
specify --no-index, the suggestion to run git-status
is not helpful.

The patch adds a new diff_options bitfield member, no_index, that
is used instead of the special value of -2 of the rev_info field
max_count to indicate that the index is not to be used.  This makes
it possible to pass that flag down to diffcore_skip_stat_unmatch(),
which only has one diff_options parameter.

This could even become a cleanup if we removed all assignments of
max_count to a value of -2 (viz. replacement of a magic value with
a self-documenting field name) but I didn't dare to do that so late
in the rc game..

The no_index bit, if set, then tells diffcore_skip_stat_unmatch()
to not account for any skipped stat-mismatches, which avoids the
suggestion to run git-status.
Signed-off-by: NRene Scharfe <rene.scharfe@lsfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The static function read_directory in diff-lib.c is only ever called
with struct path_list lists with .strdup_paths turned on, i.e.
path_list_insert will strdup the paths for us (again).  Let's take
advantage of that and stop doing it twice.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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: NJunio C Hamano <gitster@pobox.com>

git-diff -- a/ b/ always defaulted to --no-index, primarily
because the function is_in_index() was implemented quite
incorrectly.

Noticed by Patrick Maaß and Simon Schubert independently,
initial patch was provided by Patrick but I fixed it
differently.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The diff helpers used to do the magic mode canonicalization and all the
other special mode handling by hand ("trust executable bit" and "has
symlink support" handling).

That's bogus. Use "ce_mode_from_stat()" that does this all for us.

This is also going to be required when we add support for links to other
git repositories.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This teaches git-diff-files, git-diff-index and git-diff-tree
backends to exit early under --quiet option.
Signed-off-by: NJunio C Hamano <junkio@cox.net>