match_one implements an optimized pathspec match where it only uses
fnmatch if it detects glob special characters in the pattern. Unfortunately
it didn't treat \ as a special character, so attempts to escape a glob
special character would fail even though fnmatch() supports it.
Signed-off-by: NKevin Ballard <kevin@sb.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git add *" is actually fundamentally different from "git add .", and
yeah, you should generally use the latter.

The reason? The argument list is actually something different from what
you think it is. For git, it's a "pathspec", so what actualy happens is
that in *both* cases, it will really traverse the whole tree, and then
match every file it finds against the pathspec.

So think of the arguments not as a file list, but as a random bunch of
patterns to match against the files you have!

Which is why the cost is actually approximately O(n*m), where "n" is the
size of the working tree, and "m" is the number of pathspecs.

So the reason "git add ." is fast is actually that "m" in that case is
just 1 (just one trivial pattern), and then "git add *" is slow because
"m" is large (lots of complicated patterns). In both cases, 'n' is the
same (== the whole set of files in your working tree).

Anyway, here's a trivial patch that doesn't change this fundamental fact,
but that avoids doing anything *expensive* until we've done some cheap
initial tests. It may or may not help your test-case, but it's pretty
simple and it matches the other git optimizations in this area (ie
"conceptually handle the general case, but optimize the simple cases where
we can exit early")

Notice how this patch doesn' actually change the fundamental O(n^2)
behaviour, but it makes it much cheaper by generally avoiding the
expensive 'fnmatch' and 'strlen/strncmp' when they are obviously not
needed.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When git clean is run from a subdirectory it should follow the normal
policy and only remove directories if they are passed in as a pathspec,
or -d is specified.

The fix is to send len which could be shorter than ent->len because we
have stripped the trailing '/' that read_directory adds. Additionaly
match_one() was modified to allow a name[] that is not NUL terminated.
This allows us to check if the name matched the pathspec exactly
instead of recursively.
Signed-off-by: NShawn Bohrer <shawn.bohrer@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

..and start using it for directory entry traversal (ie "git status" will
not consider entries that match an existing entry case-insensitively to
be a new file)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Right now nobody uses it, but "index_name_exists()" gets a flag so
you can enable it on a case-by-case basis.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This change removes all obvious useless if-before-free tests.
E.g., it replaces code like this:

        if (some_expression)
                free (some_expression);

with the now-equivalent:

        free (some_expression);

It is equivalent not just because POSIX has required free(NULL)
to work for a long time, but simply because it has worked for
so long that no reasonable porting target fails the test.
Here's some evidence from nearly 1.5 years ago:

    http://www.winehq.org/pipermail/wine-patches/2006-October/031544.html

FYI, the change below was prepared by running the following:

  git ls-files -z | xargs -0 \
  perl -0x3b -pi -e \
    's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)\s+(free\s*\(\s*\1\s*\))/$2/s'

Note however, that it doesn't handle brace-enclosed blocks like
"if (x) { free (x); }".  But that's ok, since there were none like
that in git sources.

Beware: if you do use the above snippet, note that it can
produce syntactically invalid C code.  That happens when the
affected "if"-statement has a matching "else".
E.g., it would transform this

  if (x)
    free (x);
  else
    foo ();

into this:

  free (x);
  else
    foo ();

There were none of those here, either.

If you're interested in automating detection of the useless
tests, you might like the useless-if-before-free script in gnulib:
[it *does* detect brace-enclosed free statements, and has a --name=S
 option to make it detect free-like functions with different names]

  http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=build-aux/useless-if-before-free

Addendum:
  Remove one more (in imap-send.c), spotted by Jean-Luc Herren <jlh@gmx.ch>.
Signed-off-by: NJim Meyering <meyering@redhat.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we process "foo/" entries in gitignore files on a system
that does not have d_type member in "struct dirent", the earlier
implementation ran lstat(2) separately when matching with
entries that came from the command line, in-tree .gitignore
files, and $GIT_DIR/info/excludes file.

This optimizes it by delaying the lstat(2) call until it becomes
absolutely necessary.

The initial idea for this change was by Jeff King, but I
optimized it further to pass pointers to around.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

A pattern "foo/" in the exclude list did not match directory
"foo", but a pattern "foo" did.  This attempts to extend the
exclude mechanism so that it would while not matching a regular
file or a symbolic link "foo".  In order to differentiate a
directory and non directory, this passes down the type of path
being checked to excluded() function.

A downside is that the recursive directory walk may need to run
lstat(2) more often on systems whose "struct dirent" do not give
the type of the entry; earlier it did not have to do so for an
excluded path, but we now need to figure out if a path is a
directory before deciding to exclude it.  This is especially bad
because an idea similar to the earlier CE_UPTODATE optimization
to reduce number of lstat(2) calls would by definition not apply
to the codepaths involved, as (1) directories will not be
registered in the index, and (2) excluded paths will not be in
the index anyway.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This creates a hash index of every single file added to the index.
Right now that hash index isn't actually used for much: I implemented a
"cache_name_exists()" function that uses it to efficiently look up a
filename in the index without having to do the O(logn) binary search,
but quite frankly, that's not why this patch is interesting.

No, the whole and only reason to create the hash of the filenames in the
index is that by modifying the hash function, you can fairly easily do
things like making it always hash equivalent names into the same bucket.

That, in turn, means that suddenly questions like "does this name exist
in the index under an _equivalent_ name?" becomes much much cheaper.

Guiding principles behind this patch:

 - it shouldn't be too costly. In fact, my primary goal here was to
   actually speed up "git commit" with a fully populated kernel tree, by
   being faster at checking whether a file already existed in the index. I
   did succeed, but only barely:

	Best before:
		[torvalds@woody linux]$ time git commit > /dev/null
		real    0m0.255s
		user    0m0.168s
		sys     0m0.088s

	Best after:

		[torvalds@woody linux]$ time ~/git/git commit > /dev/null
		real    0m0.233s
		user    0m0.144s
		sys     0m0.088s

   so some things are actually faster (~8%).

   Caveat: that's really the best case. Other things are invariably going
   to be slightly slower, since we populate that index cache, and quite
   frankly, few things really use it to look things up.

   That said, the cost is really quite small. The worst case is probably
   doing a "git ls-files", which will do very little except puopulate the
   index, and never actually looks anything up in it, just lists it.

	Before:
		[torvalds@woody linux]$ time git ls-files > /dev/null
		real    0m0.016s
		user    0m0.016s
		sys     0m0.000s

	After:
		[torvalds@woody linux]$ time ~/git/git ls-files > /dev/null
		real    0m0.021s
		user    0m0.012s
		sys     0m0.008s

   and while the thing has really gotten relatively much slower, we're
   still talking about something almost unmeasurable (eg 5ms). And that
   really should be pretty much the worst case.

   So we lose 5ms on one "benchmark", but win 22ms on another. Pick your
   poison - this patch has the advantage that it will _likely_ speed up
   the cases that are complex and expensive more than it slows down the
   cases that are already so fast that nobody cares. But if you look at
   relative speedups/slowdowns, it doesn't look so good.

 - It should be simple and clean

   The code may be a bit subtle (the reasons I do hash removal the way I
   do etc), but it re-uses the existing hash.c files, so it really is
   fairly small and straightforward apart from a few odd details.

Now, this patch on its own doesn't really do much, but I think it's worth
looking at, if only because if done correctly, the name hashing really can
make an improvement to the whole issue of "do we have a filename that
looks like this in the index already". And at least it gets real testing
by being used even by default (ie there is a real use-case for it even
without any insane filesystems).

NOTE NOTE NOTE! The current hash is a joke. I'm ashamed of it, I'm just
not ashamed of it enough to really care. I took all the numbers out of my
nether regions - I'm sure it's good enough that it works in practice, but
the whole point was that you can make a really much fancier hash that
hashes characters not directly, but by their upper-case value or something
like that, and thus you get a case-insensitive hash, while still keeping
the name and the index itself totally case sensitive.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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>

Signed-off-by: NLi Hong <leehong@pku.edu.cn>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Operations that walk directories or trees, which potentially need to
consult the .gitignore files, used to always try to open the .gitignore
file every time they entered a new directory, even when they ended up
not needing to call excluded() function to see if a path in the
directory is ignored.  This was done by push/pop exclude_per_directory()
functions that managed the data in a stack.

This changes the directory walking API to remove the need to call these
two functions.  Instead, the directory walk data structure caches the
data used by excluded() function the last time, and lazily reuses it as
much as possible.  Among the data the last check used, the ones from
deeper directories that the path we are checking is outside are
discarded, data from the common leading directories are reused, and then
the directories between the common directory and the directory the path
being checked is in are checked for .gitignore file.  This is very
similar to the way gitattributes are handled.

This API change also fixes "ls-files -c -i", which called excluded()
without setting up the gitignore data via the old push/pop functions.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Replace handcrafted reallocation with ALLOC_GROW().
Reindent "file_exists()" helper function.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This function is used to see if a path given by the user does exist
on the filesystem.  A symbolic link that does not point anywhere does
exist but running stat() on it would yield an error, and it incorrectly
said it does not exist.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In "dir_struct", each exclusion element in the exclusion stack records a
base string (pointer to the beginning with length) so that we can tell
where it came from, but this pointer is just pointing at the parameter
that is given by the caller to the push_exclude_per_directory()
function.

While read_directory_recursive() runs, calls to excluded() makes use
the data in the exclusion elements, including this base string.  The
caller of read_directory_recursive() is not supposed to free the
buffer it gave to push_exclude_per_directory() earlier, until it
returns.

The test case Bruce Stephens gave in the mailing list discussion
was simplified and added to the t3700 test.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There are inconsistencies in the way commands currently handle
the core.excludesfile configuration variable.  The problem is
the variable is too new to be noticed by anything other than
git-add and git-status.

 * git-ls-files does not notice any of the "ignore" files by
   default, as it predates the standardized set of ignore files.
   The calling scripts established the convention to use
   .git/info/exclude, .gitignore, and later core.excludesfile.

 * git-add and git-status know about it because they call
   add_excludes_from_file() directly with their own notion of
   which standard set of ignore files to use.  This is just a
   stupid duplication of code that need to be updated every time
   the definition of the standard set of ignore files is
   changed.

 * git-read-tree takes --exclude-per-directory=<gitignore>,
   not because the flexibility was needed.  Again, this was
   because the option predates the standardization of the ignore
   files.

 * git-merge-recursive uses hardcoded per-directory .gitignore
   and nothing else.  git-clean (scripted version) does not
   honor core.* because its call to underlying ls-files does not
   know about it.  git-clean in C (parked in 'pu') doesn't either.

We probably could change git-ls-files to use the standard set
when no excludes are specified on the command line and ignore
processing was asked, or something like that, but that will be a
change in semantics and might break people's scripts in a subtle
way.  I am somewhat reluctant to make such a change.

On the other hand, I think it makes perfect sense to fix
git-read-tree, git-merge-recursive and git-clean to follow the
same rule as other commands.  I do not think of a valid use case
to give an exclude-per-directory that is nonstandard to
read-tree command, outside a "negative" test in the t1004 test
script.

This patch is the first step to untangle this mess.

The next step would be to teach read-tree, merge-recursive and
clean (in C) to use setup_standard_excludes().
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In "dir_struct", each exclusion element in the exclusion stack records a
base string (pointer to the beginning with length) so that we can tell
where it came from, but this pointer is just pointing at the parameter
that is given by the caller to the push_exclude_per_directory()
function.

While read_directory_recursive() runs, calls to excluded() makes use
the data in the exclusion elements, including this base string.  The
caller of read_directory_recursive() is not supposed to free the
buffer it gave to push_exclude_per_directory() earlier, until it
returns.

The test case Bruce Stephens gave in the mailing list discussion
was simplified and added to the t3700 test.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There are inconsistencies in the way commands currently handle
the core.excludesfile configuration variable.  The problem is
the variable is too new to be noticed by anything other than
git-add and git-status.

 * git-ls-files does not notice any of the "ignore" files by
   default, as it predates the standardized set of ignore files.
   The calling scripts established the convention to use
   .git/info/exclude, .gitignore, and later core.excludesfile.

 * git-add and git-status know about it because they call
   add_excludes_from_file() directly with their own notion of
   which standard set of ignore files to use.  This is just a
   stupid duplication of code that need to be updated every time
   the definition of the standard set of ignore files is
   changed.

 * git-read-tree takes --exclude-per-directory=<gitignore>,
   not because the flexibility was needed.  Again, this was
   because the option predates the standardization of the ignore
   files.

 * git-merge-recursive uses hardcoded per-directory .gitignore
   and nothing else.  git-clean (scripted version) does not
   honor core.* because its call to underlying ls-files does not
   know about it.  git-clean in C (parked in 'pu') doesn't either.

We probably could change git-ls-files to use the standard set
when no excludes are specified on the command line and ignore
processing was asked, or something like that, but that will be a
change in semantics and might break people's scripts in a subtle
way.  I am somewhat reluctant to make such a change.

On the other hand, I think it makes perfect sense to fix
git-read-tree, git-merge-recursive and git-clean to follow the
same rule as other commands.  I do not think of a valid use case
to give an exclude-per-directory that is nonstandard to
read-tree command, outside a "negative" test in the t1004 test
script.

This patch is the first step to untangle this mess.

The next step would be to teach read-tree, merge-recursive and
clean (in C) to use setup_standard_excludes().
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Try to avoid a lot of work scanning for excluded files,
by caching some more information when setting up the exclusion
data structure.

Speeds up 'git runstatus' on a repository containing the Qt sources by 30% and
reduces the amount of instructions executed (as measured by valgrind) by a
factor of 2.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

On Fri, 19 Oct 2007, Todd T. Fries wrote:
> If DT_UNKNOWN exists, then we have to do a stat() of some form to
> find out the right type.

That happened in the case of a pathname that was ignored, and we did
not ask for "dir->show_ignored". That test used to be *together*
with the "DTYPE(de) != DT_DIR", but splitting the two tests up
means that we can do that (common) test before we even bother to
calculate the real dtype.

Of course, that optimization only matters for systems that don't
have, or don't fill in DTYPE properly.

I also clarified the real relationship between "exclude" and
"dir->show_ignored". It used to do

	if (exclude != dir->show_ignored) {
		..

which wasn't exactly obvious, because it triggers for two different
cases:

 - the path is marked excluded, but we are not interested in ignored
   files: ignore it

 - the path is *not* excluded, but we *are* interested in ignored
   files: ignore it unless it's a directory, in which case we might
   have ignored files inside the directory and need to recurse
   into it).

so this splits them into those two cases, since the first case
doesn't even care about the type.

I also made a the DT_UNKNOWN case a separate helper function,
and added some commentary to the cases.

		Linus
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

There was a function called remove_empty_dir_recursive() buried
in refs.c.  Expose a slightly enhanced version in dir.h: it can now
optionally remove a non-empty directory.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The comment did not make a good case why it makes sense.
Clarify, and remove stale comment about the caller being lazy.
The behaviour on NULL input is pretty much intentional.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The function get_relative_cwd() works just as getcwd(), only that it
takes an absolute path as additional parameter, returning the prefix
of the current working directory relative to the given path.  If the
cwd is no subdirectory of the given path, it returns NULL.

is_inside_dir() is just a trivial wrapper over get_relative_cwd().
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

ALLOC_GROW now expects the 'nr' argument to be "how much you
want" and not "how much you have". This fixes all cases
where we weren't previously adding anything to the 'nr'.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Previously, the code would always set up the excludes, and then manually
pick through the pathspec we were given, assuming that non-added but
existing paths were just ignored. This was mostly correct, but would
erroneously mark a totally empty directory as 'ignored'.

Instead, we now use the collect_ignored option of dir_struct, which
unambiguously tells us whether a path was ignored. This simplifies the
code, and means empty directories are now just not mentioned at all.

Furthermore, we now conditionally ask dir_struct to respect excludes,
depending on whether the '-f' flag has been set. This means we don't have
to pick through the result, checking for an 'ignored' flag; ignored entries
were either added or not in the first place.

We can safely get rid of the special 'ignored' flags to dir_entry, which
were not used anywhere else.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJonas Fonseca <fonseca@diku.dk>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When set, this option will cause read_directory to keep
track of which entries were ignored. While this shouldn't
effect functionality in most cases, it can make warning
messages to the user much more useful.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is in preparation for keeping two entry lists in the
dir object.

This patch adds and uses the ALLOC_GROW() macro, which
implements the commonly used idiom of growing a dynamic
array using the alloc_nr function (not just in dir.c, but
everywhere).

We also move creation of a dir_entry to dir_entry_new.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Unify naming of plumbing dirlink/gitlink concept:

git ls-files -z '*.[ch]' |
xargs -0 perl -pi -e 's/dirlink/gitlink/g;' -e 's/DIRLNK/GITLINK/g;'
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This makes "git-ls-files --others --directory --ignored" behave
as documented and consequently also fixes "git-clean -d -X".
Previously, git-clean would remove non-excluded directories
even when using the -X option.
Signed-off-by: NMichael Spang <mspang@uwaterloo.ca>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The function common_prefix() is used to find the common subdirectory of
a couple of pathnames. When checking if the next pathname matches up with
the prefix, it incorrectly checked the whole path, not just the prefix
(including the slash). Thus, the expensive part of the loop was executed
always.

The other bug is more serious: if the first and the last pathname in the
list have a longer common prefix than the common prefix for _all_ pathnames
in the list, the longer one would be chosen. This bug was probably hidden
by the fact that bash's wildcard expansion sorts the results, and the code
just so happens to work with sorted input.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When "show_other_directories" is set, that implies that we are looking
for untracked files, which obviously means that we should ignore
directories that are marked as gitlinks in the index.

This fixes "git status" in a superproject, that would otherwise always
report that subprojects were "Untracked files:"
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This is the promised cleaned-up version of teaching directory traversal
(ie the "read_directory()" logic) about subprojects. That makes "git add"
understand to add/update subprojects.

It now knows to look at the index file to see if a directory is marked as
a subproject, and use that as information as whether it should be recursed
into or not.

It also generally cleans up the handling of directory entries when
traversing the working tree, by splitting up the decision-making process
into small functions of their own, and adding a fair number of comments.

Finally, it teaches "add_file_to_cache()" that directory names can have
slashes at the end, since the directory traversal adds them to make the
difference between a file and a directory clear (it always did that, but
my previous too-ugly-to-apply subproject patch had a totally different
path for subproject directories and avoided the slash for that case).
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This just makes sure that when we do a read_directory(), we check
that the filename fits in the buffer we allocated (with a bit of
slop)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The way things are set up, you can now pass a "pathspec" to the
"read_directory()" function. If you pass NULL, it acts exactly
like it used to do (read everything). If you pass a non-NULL
pointer, it will simplify it into a "these are the prefixes
without any special characters", and stop any readdir() early if
the path in question doesn't match any of the prefixes.

NOTE! This does *not* obviate the need for the caller to do the *exact*
pathspec match later. It's a first-level filter on "read_directory()", but
it does not do the full pathspec thing. Maybe it should. But in the
meantime, builtin-add.c really does need to do first

	read_directory(dir, .., pathspec);
	if (pathspec)
		prune_directory(dir, pathspec, baselen);

ie the "prune_directory()" part will do the *exact* pathspec pruning,
while the "read_directory()" will use the pathspec just to do some quick
high-level pruning of the directories it will recurse into.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Some systems have sizeof(off_t) == 8 while sizeof(size_t) == 4.
This implies that we are able to access and work on files whose
maximum length is around 2^63-1 bytes, but we can only malloc or
mmap somewhat less than 2^32-1 bytes of memory.

On such a system an implicit conversion of off_t to size_t can cause
the size_t to wrap, resulting in unexpected and exciting behavior.
Right now we are working around all gcc warnings generated by the
-Wshorten-64-to-32 option by passing the off_t through xsize_t().

In the future we should make xsize_t on such problematic platforms
detect the wrapping and die if such a file is accessed.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

We have a number of badly checked read() calls.  Often we are
expecting read() to read exactly the size we requested or fail, this
fails to handle interrupts or short reads.  Add a read_in_full()
providing those semantics.  Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xread().
Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When '*.ig' is ignored, and you have two files f.ig and d.ig/foo
in the working tree,

	$ git add .

correctly ignored f.ig but failed to ignore d.ig/foo.  This was
caused by a thinko in an earlier commit 4888c534, when we tried
to allow adding otherwise ignored files.

After reverting that commit, this takes a much simpler approach.
When we have an unmatched pathspec that talks about an existing
pathname, we know it is an ignored path the user tried to add,
so we include it in the set of paths directory walker returned.

This does not let you say "git add -f D" on an ignored directory
D and add everything under D.  People can submit a patch to
further allow it if they want to, but I think it is a saner
behaviour to require explicit paths to be spelled out in such a
case.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This reverts commit 4888c534.

This teaches the internal read_directory() routine to return
both interesting and ignored pathnames.
Signed-off-by: NJunio C Hamano <junkio@cox.net>