This is shorter, idiomatic, and it means the compiler does
not get confused about whether our "e" pointer is valid,
letting us drop the "e = e" hack.
Signed-off-by: NJeff King <peff@peff.net>
Reviewed-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In early days of its life, I planned to make it possible to compute
"is a commit contained in all of these other commits?" with this
function, but it turned out that no caller needed it.

Just make it take two commit objects and add a comment to say what
these two functions do.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The syntax for the use of mark references in fast-import
demands either a SP (space) or LF (end-of-line) after
a mark reference.  Fast-import does not complain when garbage
appears after a mark reference in some cases.

Factor out parsing of mark references and complain if
errant characters are found.  Also be a little more careful
when parsing "inline" and SHA1s, complaining if extra
characters appear or if the form of the dataref is unrecognized.

Buggy input can cause fast-import to produce the wrong output,
silently, without error.  This makes it difficult to track
down buggy generators of fast-import streams.  An example is
seen in the last line of this commit command:

    commit refs/heads/S2
    committer Name <name@example.com> 1112912893 -0400
    data <<COMMIT
    commit message
    COMMIT
    from :1M 100644 :103 hello.c

It is missing a newline and should be:

    [...]
    from :1
    M 100644 :103 hello.c

What fast-import does is to produce a commit with the same
contents for hello.c as in refs/heads/S2^.  What the buggy
program was expecting was the contents of blob :103.  While
the resulting commit graph looked correct, the contents in
some commits were wrong.
Signed-off-by: NPete Wyckoff <pw@padd.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

As the fast-import manual explains:

	The value of <path> must be in canonical form. That is it must
	not:
	. contain an empty directory component (e.g. foo//bar is invalid),
	. end with a directory separator (e.g. foo/ is invalid),
	. start with a directory separator (e.g. /foo is invalid),

Unfortunately the "ls" command accepts these invalid syntaxes and
responds by declaring that the indicated path is missing.  This is too
subtle and causes importers to silently misbehave; better to error out
so the operator knows what's happening.

The C, R, and M commands already error out for such paths.
Reported-by: NAndrew Sayers <andrew-git@pileofstuff.org>
Analysis-by: NDavid Barr <davidbarr@google.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>

When the chosen directory has changed since it was last written to
pack, "tree_content_get" makes a deep copy of its content to scribble
on while computing the tree name, which we forgot to free.

This leak has been present since the 'ls' command was introduced in
v1.7.5-rc0~3^2~33 (fast-import: add 'ls' command, 2010-12-02).
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>

When running t9300, valgrind (correctly) complains about an
uninitialized value in write_crash_report:

  ==2971== Use of uninitialised value of size 8
  ==2971==    at 0x4164F4: sha1_to_hex (hex.c:70)
  ==2971==    by 0x4073E4: die_nicely (fast-import.c:468)
  ==2971==    by 0x43284C: die (usage.c:86)
  ==2971==    by 0x40420D: main (fast-import.c:2731)
  ==2971==  Uninitialised value was created by a heap allocation
  ==2971==    at 0x4C29B3D: malloc (vg_replace_malloc.c:263)
  ==2971==    by 0x433645: xmalloc (wrapper.c:35)
  ==2971==    by 0x405DF5: pool_alloc (fast-import.c:619)
  ==2971==    by 0x407755: pool_calloc.constprop.14 (fast-import.c:634)
  ==2971==    by 0x403F33: main (fast-import.c:3324)

Fix this by zeroing all of the 'struct tag'.  We would only need to
zero out the 'sha1' field, but this way seems more future-proof.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

On Solaris the system headers define the "tmpfile" name, which'll
cause Git compiled with Sun Studio 12 Update 1 to whine about us
redefining the name:

    "pack-write.c", line 76: warning: name redefined by pragma redefine_extname declared static: tmpfile     (E_PRAGMA_REDEFINE_STATIC)
    "sha1_file.c", line 2455: warning: name redefined by pragma redefine_extname declared static: tmpfile    (E_PRAGMA_REDEFINE_STATIC)
    "fast-import.c", line 858: warning: name redefined by pragma redefine_extname declared static: tmpfile   (E_PRAGMA_REDEFINE_STATIC)
    "builtin/index-pack.c", line 175: warning: name redefined by pragma redefine_extname declared static: tmpfile    (E_PRAGMA_REDEFINE_STATIC)

Just renaming the "tmpfile" variable to "tmp_file" in the relevant
places is the easiest way to fix this.
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Change the skeleton implementation of i18n in Git to one that can show
localized strings to users for our C, Shell and Perl programs using
either GNU libintl or the Solaris gettext implementation.

This new internationalization support is enabled by default. If
gettext isn't available, or if Git is compiled with
NO_GETTEXT=YesPlease, Git falls back on its current behavior of
showing interface messages in English. When using the autoconf script
we'll auto-detect if the gettext libraries are installed and act
appropriately.

This change is somewhat large because as well as adding a C, Shell and
Perl i18n interface we're adding a lot of tests for them, and for
those tests to work we need a skeleton PO file to actually test
translations. A minimal Icelandic translation is included for this
purpose. Icelandic includes multi-byte characters which makes it easy
to test various edge cases, and it's a language I happen to
understand.

The rest of the commit message goes into detail about various
sub-parts of this commit.

= Installation

Gettext .mo files will be installed and looked for in the standard
$(prefix)/share/locale path. GIT_TEXTDOMAINDIR can also be set to
override that, but that's only intended to be used to test Git itself.

= Perl

Perl code that's to be localized should use the new Git::I18n
module. It imports a __ function into the caller's package by default.

Instead of using the high level Locale::TextDomain interface I've
opted to use the low-level (equivalent to the C interface)
Locale::Messages module, which Locale::TextDomain itself uses.

Locale::TextDomain does a lot of redundant work we don't need, and
some of it would potentially introduce bugs. It tries to set the
$TEXTDOMAIN based on package of the caller, and has its own
hardcoded paths where it'll search for messages.

I found it easier just to completely avoid it rather than try to
circumvent its behavior. In any case, this is an issue wholly
internal Git::I18N. Its guts can be changed later if that's deemed
necessary.

See <AANLkTilYD_NyIZMyj9dHtVk-ylVBfvyxpCC7982LWnVd@mail.gmail.com> for
a further elaboration on this topic.

= Shell

Shell code that's to be localized should use the git-sh-i18n
library. It's basically just a wrapper for the system's gettext.sh.

If gettext.sh isn't available we'll fall back on gettext(1) if it's
available. The latter is available without the former on Solaris,
which has its own non-GNU gettext implementation. We also need to
emulate eval_gettext() there.

If neither are present we'll use a dumb printf(1) fall-through
wrapper.

= About libcharset.h and langinfo.h

We use libcharset to query the character set of the current locale if
it's available. I.e. we'll use it instead of nl_langinfo if
HAVE_LIBCHARSET_H is set.

The GNU gettext manual recommends using langinfo.h's
nl_langinfo(CODESET) to acquire the current character set, but on
systems that have libcharset.h's locale_charset() using the latter is
either saner, or the only option on those systems.

GNU and Solaris have a nl_langinfo(CODESET), FreeBSD can use either,
but MinGW and some others need to use libcharset.h's locale_charset()
instead.

=Credits

This patch is based on work by Jeff Epler <jepler@unpythonic.net> who
did the initial Makefile / C work, and a lot of comments from the Git
mailing list, including Jonathan Nieder, Jakub Narebski, Johannes
Sixt, Erik Faye-Lund, Peter Krefting, Junio C Hamano, Thomas Rast and
others.

[jc: squashed a small Makefile fix from Ramsay]
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NRamsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It is useful to be able to rewind a check-summed file to a certain
previous state after writing data into it using sha1write() API. The
fast-import command does this after streaming a blob data to the packfile
being generated and then noticing that the same blob has already been
written, and it does this with a private code truncate_pack() that is
commented as "Yes, this is a layering violation".

Introduce two API functions, sha1file_checkpoint(), that allows the caller
to save a state of a sha1file, and then later revert it to the saved state.
Use it to reimplement truncate_pack().
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This fixes the bug uncovered by the tests added in the previous two patches.

When an existing notes ref was loaded into the fast-import machinery, the
num_notes counter associated with that ref remained == 0, even though the
true number of notes in the loaded ref was higher. This caused a fanout
level of 0 to be used, although the actual fanout of the tree could be > 0.
Manipulating the notes tree at an incorrect fanout level causes removals to
silently fail, and modifications of existing notes to instead produce an
additional note (leaving the old object in place at a different fanout level).

This patch fixes the bug by explicitly counting the number of notes in the
notes tree whenever it looks like the num_notes counter could be wrong (when
num_notes == 0). There may be false positives (i.e. triggering the counting
when the notes tree is truly empty), but in those cases, the counting should
not take long.
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Change check_ref_format() to take a flags argument that indicates what
is acceptable in the reference name (analogous to "git
check-ref-format"'s "--allow-onelevel" and "--refspec-pattern").  This
is more convenient for callers and also fixes a failure in the test
suite (and likely elsewhere in the code) by enabling "onelevel" and
"refspec-pattern" to be allowed independently of each other.

Also rename check_ref_format() to check_refname_format() to make it
obvious that it deals with refnames rather than references themselves.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

'reset' command makes fast-import start a branch from scratch. It's name
is kept in lookup table but it's sha1 is null_sha1 (special value).
'notemodify' command can be used to add a note on branch head given it's
name. lookup_branch() is used it that case and it doesn't check for
null_sha1. So fast-import writes a note for null_sha1 object instead of
giving a error.

Add a check to deny adding a note on empty branch and add a corresponding
test.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

'reset' command makes fast-import start a branch from scratch. It's name
is kept in lookup table but it's sha1 is null_sha1 (special value).
'tag' command can be used to tag a branch by it's name. lookup_branch()
is used it that case and it doesn't check for null_sha1. So fast-import
writes a tag for null_sha1 object instead of giving a error.

Add a check to deny tagging an empty branch and add a corresponding test.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

fast-import allows to tag objects by sha1 and to query sha1 of objects
being imported. So it should allow to tag these objects, make it do so.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

fast-import allows to create an annotated tag that annotates a blob,
via mark or direct sha1 specification.

For mark it works, for sha1 it tries to read the object. It tries to
do so via read_sha1_file, and then checks the size to be at least 46.

That's weird, let's just allow to (annotated) tag any object referenced
by sha1. If the object originates from our packfile, we still fail though.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Delta base for blobs is chosen as a previously saved blob. If we
treat cat-blob's blob as a delta base for the next blob, nothing
is likely to become worse.

For fast-import stream producer like svn-fe cat-blob is used like
following:
- svn-fe reads file delta in svn format
- to apply it, svn-fe asks cat-blob 'svn delta base'
- applies 'svn delta' to the response
- produces a blob command to store the result

Currently there is no way for svn-fe to give fast-import a hint on
object delta base. While what's requested in cat-blob is most of
the time a best delta base possible. Of course, it could be not a
good delta base, but we don't know any better one anyway.

So do treat cat-blob's result as a delta base for next blob. The
profit is nice: 2x to 7x reduction in pack size AND 1.2x to 3x
time speedup due to diff_delta being faster on good deltas. git gc
--aggressive can compress it even more, by 10% to 70%, utilizing
more cpu time, real time and 3 cpu cores.

Tested on 213M and 2.7G fast-import streams, resulting packs are 22M
and 113M, import time is 7s and 60s, both streams are produced by
svn-fe, sniffed and then used as raw input for fast-import.

For git-fast-export produced streams there is no change as it doesn't
use cat-blob and doesn't try to reorder blobs in some smart way to
make successive deltas small.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Acked-by: NDavid Barr <davidbarr@google.com>
Acked-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It's an interesting number, how often do we try to deltify each type of
objects and how often do we succeed. So do add it to stats.

Success doesn't mean much gain in pack size though. As we allow delta to
be as big as (data.len - 20). And delta close to data.len gains nothing
compared to no delta at all even after zlib compression (delta is pretty
much the same as data, just with few modifications).

We should try to make less attempts that result in huge deltas as these
consume more cpu than trivial small deltas. Either by choosing a better
delta base or reducing delta size upper bound or doing less delta attempts
at all.

Currently, delta base for blobs is a waste literally. Each blob delta
base is chosen as a previously stored blob. Disabling deltas for blobs
doesn't increase pack size and reduce import time, or at least doesn't
increase time for all fast-import streams I've tried.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Acked-by: NDavid Barr <davidbarr@google.com>
Acked-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

To produce deltas for tree objects fast-import tracks two versions
of tree's entries - base and current one. Base version stands both
for a delta base of this tree, and for a entry inside a delta base
of a parent tree. So care should be taken to keep it in sync.

tree_content_set cuts away a whole subtree and replaces it with a
new one (or NULL for lazy load of a tree with known sha1). It
keeps a base sha1 for this subtree (needed for parent tree). And
here is the problem, 'subtree' tree root doesn't have the implied
base version entries.

Adjusting the subtree to include them would mean a deep rewrite of
subtree. Invalidating the subtree base version would mean recursive
invalidation of parents' base versions. So just mark this tree as
do-not-delta me. Abuse setuid bit for this purpose.

tree_content_replace is the same as tree_content_set except that is
is used to replace the root, so just clearing base sha1 here (instead
of setting the bit) is fine.

[di: log message]
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The documentation declares following identity format:
(<name> SP)? LT <email> GT
where name is any string without LF and LT characters.
But fast-import just accepts any string up to first GT
instead of checking the whole format, and moreover just
writes it as is to the commit object.

git-fsck checks for [^<\n]* <[^<>\n]*> format. Note that the
space is mandatory. And the space quirk is already handled via
extending the string to the left when needed.

Modify fast-import input identity format to a slightly stricter
one - deny LF, LT and GT in both <name> and <email>. And check
for it.

This is stricter then git-fsck as fsck accepts "Name> <email>"
currently, but soon fsck check will be adjusted likewise.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

fast-import format declares 'committer_name SP' to be optional in
'committer_name SP LT email GT'. But for a (commit) object SP is
obligatory while zero length committer_name is ok. git-fsck checks
that SP is present, so fast-import must prepend it if the name SP
part is omitted. It doesn't do so and thus for "LT email GT" ident
it writes a bad object.

Name cannot contain LT or GT, ident always comes after SP in fast-import.
So if ident starts with LT reuse the SP as if a valid 'SP LT email GT'
ident was passed.

This fixes a ident parsing bug for a well-formed fast-import input.
Though the parsing is still loose and can accept a ill-formed input.
Signed-off-by: NDmitry Ivankov <divanorama@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add a 'done' command that causes fast-import to stop reading from the
stream and exit.

If the new --done command line flag was passed on the command line
(or a "feature done" declaration included at the start of the stream),
make the 'done' command mandatory.  So "git fast-import --done"'s
input format will be prefix-free, making errors easier to detect when
they show up as early termination at some convenient time of the
upstream of a pipe writing to fast-import.

Another possible application of the 'done' command would to be allow a
fast-import stream that is only a small part of a larger encapsulating
stream to be easily parsed, leaving the file offset after the "done\n"
so the other application can pick up from there.  This patch does not
teach fast-import to do that --- fast-import still uses buffered input
(stdio).
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NSverre Rabbelier <srabbelier@gmail.com>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The size of objects we read from the repository and data we try to put
into the repository are represented in "unsigned long", so that on larger
architectures we can handle objects that weigh more than 4GB.

But the interface defined in zlib.h to communicate with inflate/deflate
limits avail_in (how many bytes of input are we calling zlib with) and
avail_out (how many bytes of output from zlib are we ready to accept)
fields effectively to 4GB by defining their type to be uInt.

In many places in our code, we allocate a large buffer (e.g. mmap'ing a
large loose object file) and tell zlib its size by assigning the size to
avail_in field of the stream, but that will truncate the high octets of
the real size. The worst part of this story is that we often pass around
z_stream (the state object used by zlib) to keep track of the number of
used bytes in input/output buffer by inspecting these two fields, which
practically limits our callchain to the same 4GB limit.

Wrap z_stream in another structure git_zstream that can express avail_in
and avail_out in unsigned long. For now, just die() when the caller gives
a size that cannot be given to a single zlib call. In later patches in the
series, we would make git_inflate() and git_deflate() internally loop to
give callers an illusion that our "improved" version of zlib interface can
operate on a buffer larger than 4GB in one go.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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

Wrap deflateInit, deflate, and deflateEnd for everybody, and the sole use
of deflateInit2 in remote-curl.c to tell the library to use gzip header
and trailer in git_deflate_init_gzip().

There is only one caller that cares about the status from deflateEnd().
Introduce git_deflate_end_gently() to let that sole caller retrieve the
status and act on it (i.e. die) for now, but we would probably want to
make inflate_end/deflate_end die when they ran out of memory and get
rid of the _gently() kind.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

While refactoring the options parser in bc3c79ae (fast-import: add
(non-)relative-marks feature, 2009-12-04), it was made too lenient
for options that take no argument, fix that.
Signed-off-by: NSverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The pack-objects command should take notice of the object file and
refrain from attempting to delta large ones, to be consistent with
the fast-import command.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fix warnings from 'make check'.

 - These files don't include 'builtin.h' causing sparse to complain that
   cmd_* isn't declared:

   builtin/clone.c:364, builtin/fetch-pack.c:797,
   builtin/fmt-merge-msg.c:34, builtin/hash-object.c:78,
   builtin/merge-index.c:69, builtin/merge-recursive.c:22
   builtin/merge-tree.c:341, builtin/mktag.c:156, builtin/notes.c:426
   builtin/notes.c:822, builtin/pack-redundant.c:596,
   builtin/pack-refs.c:10, builtin/patch-id.c:60, builtin/patch-id.c:149,
   builtin/remote.c:1512, builtin/remote-ext.c:240,
   builtin/remote-fd.c:53, builtin/reset.c:236, builtin/send-pack.c:384,
   builtin/unpack-file.c:25, builtin/var.c:75

 - These files have symbols which should be marked static since they're
   only file scope:

   submodule.c:12, diff.c:631, replace_object.c:92, submodule.c:13,
   submodule.c:14, trace.c:78, transport.c:195, transport-helper.c:79,
   unpack-trees.c:19, url.c:3, url.c:18, url.c:104, url.c:117, url.c:123,
   url.c:129, url.c:136, thread-utils.c:21, thread-utils.c:48

 - These files redeclare symbols to be different types:

   builtin/index-pack.c:210, parse-options.c:564, parse-options.c:571,
   usage.c:49, usage.c:58, usage.c:63, usage.c:72

 - These files use a literal integer 0 when they really should use a NULL
   pointer:

   daemon.c:663, fast-import.c:2942, imap-send.c:1072, notes-merge.c:362

While we're in the area, clean up some unused #includes in builtin files
(mostly exec_cmd.h).
Signed-off-by: NStephen Boyd <bebarino@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In a struct definitions, unlike functions, the prevailing style is for
the opening brace to go on the same line as the struct name, like so:

 struct foo {
	int bar;
	char *baz;
 };

Indeed, grepping for 'struct [a-z_]* {$' yields about 5 times as many
matches as 'struct [a-z_]*$'.

Linus sayeth:

 Heretic people all over the world have claimed that this inconsistency
 is ...  well ...  inconsistent, but all right-thinking people know that
 (a) K&R are _right_ and (b) K&R are right.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If a pack file is small enough that its entire contents fits within
one mmap window, mmap the file and then immediately close its file
descriptor.  This reduces the number of file descriptors that are
needed to read from repositories with many tiny pack files, such
as one that has received 1000 pushes (and created 1000 small pack
files) since its last repack.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The dereference() function to peel a tree-ish and find the underlying
tree expects arithmetic to (void *) to work on byte addresses.  We
should be reading the text of objects through a char * anyway.
Noticed-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>

Remove two globals, pack_idx_default version and pack_idx_off32_limit,
and place them in a pack_idx_option structure.  Allow callers to pass
it to write_idx_file() as a parameter.

Adjust all callers to the API change.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Lazy fast-import frontend authors that want to rely on the backend to
keep track of the content of the imported trees _almost_ have what
they need in the 'cat-blob' command (v1.7.4-rc0~30^2~3, 2010-11-28).
But it is not quite enough, since

 (1) cat-blob can be used to retrieve the content of files, but
     not their mode, and

 (2) using cat-blob requires the frontend to keep track of a name
     (mark number or object id) for each blob to be retrieved

Introduce an 'ls' command to complement cat-blob and take care of the
remaining needs.  The 'ls' command finds what is at a given path
within a given tree-ish (tag, commit, or tree):

	'ls' SP <dataref> SP <path> LF

or in fast-import's active commit:

	'ls' SP <path> LF

The response is a single line sent through the cat-blob channel,
imitating ls-tree output.  So for example:

	FE> ls :1 Documentation
	gfi> 040000 tree 9e6c2b599341d28a2a375f8207507e0a2a627fe9	Documentation
	FE> ls 9e6c2b599341d28a2a375f8207507e0a2a627fe9 git-fast-import.txt
	gfi> 100644 blob 4f92954396e3f0f97e75b6838a5635b583708870	git-fast-import.txt
	FE> ls :1 RelNotes
	gfi> 120000 blob b942e499449d97aeb50c73ca2bdc1c6e6d528743	RelNotes
	FE> cat-blob b942e499449d97aeb50c73ca2bdc1c6e6d528743
	gfi> b942e499449d97aeb50c73ca2bdc1c6e6d528743 blob 32
	gfi> Documentation/RelNotes/1.7.4.txt

The most interesting parts of the reply are the first word, which is
a 6-digit octal mode (regular file, executable, symlink, directory,
or submodule), and the part from the second space to the tab, which is
a <dataref> that can be used in later cat-blob, ls, and filemodify (M)
commands to refer to the content (blob, tree, or commit) at that path.

If there is nothing there, the response is "missing some/path".

The intent is for this command to be used to read files from the
active commit, so a frontend can apply patches to them, and to copy
files and directories from previous revisions.

For example, proposed updates to svn-fe use this command in place of
its internal representation of the repository directory structure.
This simplifies the frontend a great deal and means support for
resuming an import in a separate fast-import run (i.e., incremental
import) is basically free.
Signed-off-by: NDavid Barr <david.barr@cordelta.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Improved-by: NJunio C Hamano <gitster@pobox.com>
Improved-by: NSverre Rabbelier <srabbelier@gmail.com>

Here is a 'feature' command for streams to use to require support for
the notemodify (N) command.

When the 'feature' facility was introduced (v1.7.0-rc0~95^2~4,
2009-12-04), the notes import feature was old news (v1.6.6-rc0~21^2~8,
2009-10-09) and it was not obvious it deserved to be a named feature.
But now that is clear, since all major non-git fast-import backends
lack support for it.

Details: on git version with this patch applied, any "feature notes"
command in the features/options section at the beginning of a stream
will be treated as a no-op.  On fast-import implementations without
the feature (and older git versions), the command instead errors out
with a message like

	This version of fast-import does not support feature notes.

So by declaring use of notes at the beginning of a stream, frontends
can avoid wasting time and other resources when the backend does not
support notes.  (This would be especially important for backends that
do not support rewinding history after a botched import.)
Improved-by: NThomas Rast <trast@student.ethz.ch>
Improved-by: NSverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Normal git processes do not allow one to build a tree with an empty
subtree entry without trying hard at it.  This is in keeping with the
general UI philosophy: git tracks content, not empty directories.

v1.7.3-rc0~75^2 (2010-06-30) changed that by making it easy to include
an empty subtree in fast-import's active commit:

	M 040000 4b825dc642cb6eb9a060e54bf8d69288fbee4904 subdir

One can trigger this by reading an empty tree (for example, the tree
corresponding to an empty root commit) and trying to move it to a
subtree.  It is better and more closely analogous to 'git read-tree
--prefix' to treat such commands as requests to remove the subtree.
Noticed-by: NDavid Barr <david.barr@cordelta.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When a frontend uses a marks file to ensure its state persists between
runs, it may represent "clean slate" when bootstrapping with "no marks
yet". In such a case, feeding the last state with --import-marks and
saving the state after the current run with --export-marks would be a
natural thing to do.

The --import-marks option however errors out when the specified marks file
doesn't exist; this makes bootstrapping a bit difficult.  The location of
the marks file becomes backend-dependent when --relative-marks is in
effect, and the frontend cannot check for the existence of the file in
such a case.

The --import-marks-if-exists option does the same thing as --import-marks
but does not flag an error if the named file does not exist yet to help
these frontends.
Helped-by: NJunio C Hamano <gitster@pobox.com>
Helped-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NRamkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The new rule: a "cat-blob" can be inserted wherever a comment is
allowed, which means at the start of any line except in the middle of
a "data" command.

This saves frontends from having to loop over everything they want to
commit in the next commit and cat-ing the necessary objects in
advance.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NDavid Barr <david.barr@cordelta.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

New objects written by fast-import are not available immediately.
Until a checkpoint has been started and finishes writing the pack
index, any new blobs will not be accessible using standard git tools.

So introduce a new way to access them: a "cat-blob" command in the
command stream requests for fast-import to print a blob to stdout or a
file descriptor specified by the argument to --cat-blob-fd.  The value
for cat-blob-fd cannot be specified in the stream because that would
be a layering violation: the decision of where to direct a stream has
to be made when fast-import is started anyway, so we might as well
make the stream format is independent of that detail.

Output uses the same format as "git cat-file --batch".

Thanks to Sverre Rabbelier and Sam Vilain for guidance in designing
the protocol.
Based-on-patch-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NDavid Barr <david.barr@cordelta.com>
Acked-by: NRamkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Check the result from strtoul to avoid accepting arguments like
--depth=-1 and --active-branches=foo,bar,baz.
Requested-by: NRamkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It can be tedious to wait for a multi-million-revision import.
Unfortunately it is hard to spy on the import because fast-import
works by continuously streaming out objects, without updating the pack
index or refs until a checkpoint command or the end of the stream.

So allow the impatient operator to request checkpoints by sending a
signal, like so:

	killall -USR1 git-fast-import

When receiving such a signal, fast-import would schedule a checkpoint
to take place after the current top-level command (usually a "commit"
or "blob" request) finishes.

Caveats: just like ordinary checkpoint commands, such requests slow
down the import.  Switching to a new pack at a suboptimal moment is
also likely to result in a less dense initial collection of packs.
That's the price.
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

More often than not, find_object is called for recently inserted objects.
Optimise for this case by inserting new entries at the start of the chain.
This doesn't affect the cost of new inserts but reduces the cost of find
and insert for existing object entries.
Signed-off-by: NDavid Barr <david.barr@cordelta.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>