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>

This makes the name hash removal function (which really just sets the
bit that disables lookups of it) available to external routines, and
makes read_cache_unmerged() use it when it drops an unmerged entry from
the index.

It's renamed to remove_index_entry(), and we drop the (unused) 'istate'
argument.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When invalidating unmerged entries in the index, we used to set
their ce_mode to 0 to note the fact that they do not matter
anymore which also made sure that later unpack_trees() call
would not reuse them.  Instead just remove them from the index.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
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>

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>

Remove remaining double close(2)'s.  i.e. close() before
commit_locked_index() or commit_lock_file().
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is a follow-up to f34f2b0b; list_tree() function is where it
first notices that the command line fed too many trees for us to
handle, so move the error exit message to there, and raise the
MAX_TREES to 8 (not that it matters very much in practice).
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

For multi-base merges, we allowed read-tree -m to take more than
three trees (the last two are our and their branches, and all the
earlier ones, typically one but potentially more, are used as the
merge base).  Unfortunately, the conversion done by commit 933bf40a
broke this.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This doesn't actually change any real code, but it changes the interface
to unpack_trees() to take an array of "struct tree_desc" entries, the same
way the tree-walk.c functions do.

The reason for this is that we would be much better off if we can do the
tree-unpacking using the generic "traverse_trees()" functionality instead
of having to the special "unpack" infrastructure.

This really is a pretty minimal diff, just to change the calling
convention. It passes all the tests, and looks sane. There were only two
users of "unpack_trees()": builtin-read-tree and merge-recursive, and I
tried to keep the changes minimal.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

read-tree is already marked with RUN_SETUP in git.c, so there is
no need to call setup_git_directory() a second time.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJakub Narebski <jnareb@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The existing code is not wrong per-se, but it started scanning the index
from a location that does not match the tree being read, and wasted
cycles.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This corrects the interface mistake of the previous one, and
gives a command line parameter to the only plumbing command that
currently needs it: "git-read-tree".

We can add the calls to set_alternate_index_output() to other
plumbing commands that update the index if/when needed.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When defined, this allows plumbing commands that update the
index (add, apply, checkout-index, merge-recursive, mv,
read-tree, rm, update-index, and write-tree) to write their
resulting index to an alternative index file while holding a
lock to the original index file.  With this, git-commit that
jumps the index does not have to make an extra copy of the index
file, and more importantly, it can do the update while holding
the lock on the index.

However, I think the interface to let an environment variable
specify the output is a mistake, as shown in the documentation.
If a curious user has the environment variable set to something
other than the file GIT_INDEX_FILE points at, almost everything
will break.  This should instead be a command line parameter to
tell these plumbing commands to write the result in the named
file, to prevent stupid mistakes.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJames Bowes <jbowes@dangerouslyinc.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This removes slightly more lines than it adds, but the real reason for
doing this is that future optimizations will require more setup of the
tree descriptor, and so we want to do it in one place.

Also renamed the "desc.buf" field to "desc.buffer" just to trigger
compiler errors for old-style manual initializations, making sure I
didn't miss anything.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This mechanically converts strncmp() to use prefixcmp(), but only when
the parameters match specific patterns, so that they can be verified
easily.  Leftover from this will be fixed in a separate step, including
idiotic conversions like

    if (!strncmp("foo", arg, 3))

  =>

    if (!(-prefixcmp(arg, "foo")))

This was done by using this script in px.perl

   #!/usr/bin/perl -i.bak -p
   if (/strncmp\(([^,]+), "([^\\"]*)", (\d+)\)/ && (length($2) == $3)) {
           s|strncmp\(([^,]+), "([^\\"]*)", (\d+)\)|prefixcmp($1, "$2")|;
   }
   if (/strncmp\("([^\\"]*)", ([^,]+), (\d+)\)/ && (length($1) == $3)) {
           s|strncmp\("([^\\"]*)", ([^,]+), (\d+)\)|(-prefixcmp($2, "$1"))|;
   }

and running:

   $ git grep -l strncmp -- '*.c' | xargs perl px.perl
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This documents the new option to read-tree that is used for the
improved "branch switching" code.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This follows up commit ed93b449 where we removed overcautious
"working file will be lost" check.

A new option "--exclude-per-directory=.gitignore" can be used to
tell the "git-read-tree" command that the user does not mind
losing contents in untracked files in the working tree, if they
need to be overwritten by a merge (either a two-way "switch
branches" merge, or a three-way merge).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This abstracts away the size of the hash values when copying them
from memory location to memory location, much as the introduction
of hashcmp abstracted away hash value comparsion.

A few call sites were using char* rather than unsigned char* so
I added the cast rather than open hashcpy to be void*.  This is a
reasonable tradeoff as most call sites already use unsigned char*
and the existing hashcmp is also declared to be unsigned char*.

[jc: Splitted the patch to "master" part, to be followed by a
 patch for merge-recursive.c which is not in "master" yet.

 Fixed the cast in the latter hunk to combine-diff.c which was
 wrong in the original.

 Also converted ones left-over in combine-diff.c, diff-lib.c and
 upload-pack.c ]
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

[jc: I needed to hand merge the changes to the updated codebase,
 so the result needs to be checked.]
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Most of the callers except the one in refs.c use the function to
update the index file.  Among the index writers, everybody
except write-tree dies if they cannot open it for writing.

This gives the function an extra argument, to tell it to die
when it cannot create a new file as the lockfile.

The only caller that does not have to die is write-tree, because
updating the index for the cache-tree part is optional and not
being able to do so does not affect the correctness.  I think we
do not have to be so careful and make the failure into die() the
same way as other callers, but that would be a different patch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Recent changes to built-ins broke committing from subdirectory,
because the unused parameter "prefix" shadowed a global variable.

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

This will allow merge-recursive to use the read-tree functionality
without exec()ing git-read-tree.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Basically, the options are passed by a struct unpack_trees_options now.
That's all.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This changes the calling convention of built-in commands and
passes the "prefix" (i.e. pathname of $PWD relative to the
project root level) down to them.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When path foo/bar existed in the working tree, checkout -f to switch to
a branch that has a file foo silently did a wrong thing.  It failed to
remove the directory foo, did not check out the file foo, and the worst
of all it did not report any errors.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

In a handful places, we use C99 structure and array
initializers, which some compilers do not support.

This can be handy when you are trying to compile GIT on a
Solaris system that has an older C compiler, for example.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Empty initializers for structures are not allowed in ANSI C99. This patch
removes such an initializer from `builtin-read-tree.c'. Since the struct was
static (and is therefore implicitely initialized to zero anyway) it wasn't
actually needed.
Signed-off-by: NFlorian Forster <octo@verplant.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The framework to create lockfiles that are removed at exit is
first used to reliably write the index file, but it is
applicable to other things, so stop calling it "cache_file".

This also rewords a few remaining error message that called the
index file "cache file".
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Anton Blanchard spotted that watching checkout stage of a clone
on a slow terminal takes ages because it forgot to clear the
"once a second happened" flag, so instead of updates the
percentage output for every file it checks out after the first
second has passed.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

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

The earlier "git reset --hard" simplification stopped removing
leftover working tree files from a failed automerge, when
switching back to the HEAD version that does not have the
paths.

This patch, instead of removing the unmerged paths from the
index, drops them down to stage#0 but marks them with mode=0
(the same "to be deleted" marker we internally use for paths
deleted by the merge).  one_way_merge() function and the
functions it calls already know what to do with them -- if the
tree we are reading has the path the working tree file is
overwritten, and if it doesn't the working tree file is
removed.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds a "tree_entry()" function that combines the common operation of
doing a "tree_entry_extract()" + "update_tree_entry()".

It also has a simplified calling convention, designed for simple loops
that traverse over a whole tree: the arguments are pointers to the tree
descriptor and a name_entry structure to fill in, and it returns a boolean
"true" if there was an entry left to be gotten in the tree.

This allows tree traversal with

	struct tree_desc desc;
	struct name_entry entry;

	desc.buf = tree->buffer;
	desc.size = tree->size;
	while (tree_entry(&desc, &entry) {
		... use "entry.{path, sha1, mode, pathlen}" ...
	}

which is not only shorter than writing it out in full, it's hopefully less
error prone too.

[ It's actually a tad faster too - we don't need to recalculate the entry
  pathlength in both extract and update, but need to do it only once.
  Also, some callers can avoid doing a "strlen()" on the result, since
  it's returned as part of the name_entry structure.

  However, by now we're talking just 1% speedup on "git-rev-list --objects
  --all", and we're definitely at the point where tree walking is no
  longer the issue any more. ]

NOTE! Not everybody wants to use this new helper function, since some of
the tree walkers very much on purpose do the descriptor update separately
from the entry extraction. So the "extract + update" sequence still
remains as the core sequence, this is just a simplified interface.

We should probably add a silly two-line inline helper function for
initializing the descriptor from the "struct tree" too, just to cut down
on the noise from that common "desc" initializer.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

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

The old tree_entry_list is dead, long live the unified single tree
parser.

Yes, we now still have a compatibility function to create a bogus
tree_entry_list in builtin-read-tree.c, but that is now entirely local
to that very messy piece of code.

I'd love to clean read-tree.c up too, but I'm too scared right now, so
the best I can do is to just contain the damage, and try to make sure
that no new users of the tree_entry_list sprout up by not having it as
an exported interface any more.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Instead, just use the tree buffer directly, and use the tree-walk
infrastructure to walk the buffers instead of the tree-entry list.

The tree-entry list is inefficient, and generates tons of small
allocations for no good reason. The tree-walk infrastructure is
generally no harder to use than following a linked list, and allows
us to do most tree parsing in-place.

Some programs still use the old tree-entry lists, and are a bit
painful to convert without major surgery. For them we have a helper
function that creates a temporary tree-entry list on demand.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Use the raw tree walker instead.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>